Heart Failure

The investigational, next-generation cardiac myosin inhibitor aficamten (previously CK-274, Cytokinetics) continues to show promise as a potential treatment for hypertrophic cardiomyopathy (HCM).

Today, the company announced positive topline results from cohort 3 of the REDWOOD-HCM phase 2 clinical trial, which included 13 patients with symptomatic obstructive HCM and a resting or post-Valsalva left ventricular outflow tract pressure gradient (LVOT-G) of 50 mm Hg or greater whose background therapy included disopyramide.

Treatment with aficamten led to substantial reductions in the average resting LVOT-G, as well as the post-Valsalva LVOT-G (defined as resting gradient less than 30 mm Hg and post-Valsalva gradient less than 50 mm Hg), the company reported.

These “clinically relevant” decreases in pressure gradients were achieved with only modest decreases in average left ventricular ejection fraction (LVEF), the company said. 

In no patient did LVEF fall below the prespecified safety threshold of 50%.

New York Heart Association (NYHA) functional class was improved in most patients.

The safety and tolerability of aficamten in cohort 3 were consistent with previous experience in the REDWOOD-HCM trial, with no treatment interruptions and no serious treatment-related adverse events.

The pharmacokinetic data from cohort 3 are similar to those observed in REDWOOD-HCM cohorts 1 and 2, which included HCM patients taking background medications exclusive of disopyramide, as reported previously by this news organization.

“We are encouraged by the clinically relevant reductions in the LVOT gradient observed in these medically refractory patients and are pleased with the safety profile of aficamten when administered in combination with disopyramide,” Fady Malik, MD, PhD, Cytokinetics’ executive vice president of research and development, said in a news release.

“These results represent the first report of patients with obstructive HCM treated with a combination of a cardiac myosin inhibitor and disopyramide and support our plan to include this patient population in SEQUOIA-HCM, our phase 3 trial, which is important, given these patients have exhausted other available medical therapies,” Dr. Malik said.

The results from cohort 3 of the REDWOOD-HCM trial will be presented at the upcoming American College of Cardiology Annual Meeting in April.

A version of this article first appeared on Medscape.com.

The investigational, next-generation cardiac myosin inhibitor aficamten (previously CK-274, Cytokinetics) continues to show promise as a potential treatment for hypertrophic cardiomyopathy (HCM).

Today, the company announced positive topline results from cohort 3 of the REDWOOD-HCM phase 2 clinical trial, which included 13 patients with symptomatic obstructive HCM and a resting or post-Valsalva left ventricular outflow tract pressure gradient (LVOT-G) of 50 mm Hg or greater whose background therapy included disopyramide.

Treatment with aficamten led to substantial reductions in the average resting LVOT-G, as well as the post-Valsalva LVOT-G (defined as resting gradient less than 30 mm Hg and post-Valsalva gradient less than 50 mm Hg), the company reported.

These “clinically relevant” decreases in pressure gradients were achieved with only modest decreases in average left ventricular ejection fraction (LVEF), the company said. 

In no patient did LVEF fall below the prespecified safety threshold of 50%.

New York Heart Association (NYHA) functional class was improved in most patients.

The safety and tolerability of aficamten in cohort 3 were consistent with previous experience in the REDWOOD-HCM trial, with no treatment interruptions and no serious treatment-related adverse events.

The pharmacokinetic data from cohort 3 are similar to those observed in REDWOOD-HCM cohorts 1 and 2, which included HCM patients taking background medications exclusive of disopyramide, as reported previously by this news organization.

“We are encouraged by the clinically relevant reductions in the LVOT gradient observed in these medically refractory patients and are pleased with the safety profile of aficamten when administered in combination with disopyramide,” Fady Malik, MD, PhD, Cytokinetics’ executive vice president of research and development, said in a news release.

“These results represent the first report of patients with obstructive HCM treated with a combination of a cardiac myosin inhibitor and disopyramide and support our plan to include this patient population in SEQUOIA-HCM, our phase 3 trial, which is important, given these patients have exhausted other available medical therapies,” Dr. Malik said.

The results from cohort 3 of the REDWOOD-HCM trial will be presented at the upcoming American College of Cardiology Annual Meeting in April.

A version of this article first appeared on Medscape.com.

The investigational, next-generation cardiac myosin inhibitor aficamten (previously CK-274, Cytokinetics) continues to show promise as a potential treatment for hypertrophic cardiomyopathy (HCM).

Today, the company announced positive topline results from cohort 3 of the REDWOOD-HCM phase 2 clinical trial, which included 13 patients with symptomatic obstructive HCM and a resting or post-Valsalva left ventricular outflow tract pressure gradient (LVOT-G) of 50 mm Hg or greater whose background therapy included disopyramide.

Treatment with aficamten led to substantial reductions in the average resting LVOT-G, as well as the post-Valsalva LVOT-G (defined as resting gradient less than 30 mm Hg and post-Valsalva gradient less than 50 mm Hg), the company reported.

These “clinically relevant” decreases in pressure gradients were achieved with only modest decreases in average left ventricular ejection fraction (LVEF), the company said. 

In no patient did LVEF fall below the prespecified safety threshold of 50%.

New York Heart Association (NYHA) functional class was improved in most patients.

The safety and tolerability of aficamten in cohort 3 were consistent with previous experience in the REDWOOD-HCM trial, with no treatment interruptions and no serious treatment-related adverse events.

The pharmacokinetic data from cohort 3 are similar to those observed in REDWOOD-HCM cohorts 1 and 2, which included HCM patients taking background medications exclusive of disopyramide, as reported previously by this news organization.

“We are encouraged by the clinically relevant reductions in the LVOT gradient observed in these medically refractory patients and are pleased with the safety profile of aficamten when administered in combination with disopyramide,” Fady Malik, MD, PhD, Cytokinetics’ executive vice president of research and development, said in a news release.

“These results represent the first report of patients with obstructive HCM treated with a combination of a cardiac myosin inhibitor and disopyramide and support our plan to include this patient population in SEQUOIA-HCM, our phase 3 trial, which is important, given these patients have exhausted other available medical therapies,” Dr. Malik said.

The results from cohort 3 of the REDWOOD-HCM trial will be presented at the upcoming American College of Cardiology Annual Meeting in April.

A version of this article first appeared on Medscape.com.

Why some COVID-19 vaccines seem occasionally to cause a distinctive form of myocarditis, and why adolescent boys and young men appear most vulnerable, remain a mystery. But the entity’s prevalence, nuances of presentation, and likely clinical course have come into sharper view after recent additions to the literature.  

Two new publications all but confirm that the rare cases of myocarditis closely following vaccination against SARS-CoV-2, primarily with one of the mRNA-based vaccines from Pfizer-BioNTech and Moderna, is a clinically different creature from myocarditis physicians were likely to see before the pandemic.

A third report unveils rates of hospitalization for myocarditis linked to Pfizer-BioNTech vaccination in the 12- to 15-year age group, based on active surveillance across Israel. Of note, the rates were lower than corresponding numbers among the country’s 16- to 19-year-olds published in late 2021 by the same authors.
 

No link with CoronaVac

A case-control study covering almost the entire population of Hong Kong from February to August 2021 confirms a slight but significant excess risk for myocarditis and, to a lesser degree, pericarditis, after injections of the Pfizer-BioNTech vaccine. As consistently reported from other studies, the risks were highest in adolescent and young adult males and after a second dose.

The study estimated an overall carditis incidence of 5.7 cases per million doses of Pfizer-BioNTech, for a risk 3.5 times that in the unvaccinated Hong Kong population. Carditis rates after a first dose were about 2.5 per million and 10 per million after a second dose.

Hong Kong launched its public SARS-CoV-2 immunization program in late February 2021 with the Chinese-made CoronaVac (Sinovac) inactivated-virus vaccine, and introduced the mRNA-based alternative several weeks later. By August 2021, the vaccines had reached about 3.3 million people in the region – 49% of the Hong Kong population at least 12 years of age.

In a novel finding, there were no excesses in carditis cases after CoronaVac vaccination. The difference between vaccines likely isn’t caused by chance, because three-fourths of the carditis-associated Pfizer-BioNTech injections arose within a week, whereas “71% of cases following the use of CoronaVac occurred more than 30 days after vaccination,” senior author Ian Chi Kei Wong, PhD, University of Hong Kong, said in an interview.

“This onset distribution for cases having received CoronaVac demonstrates that it is highly unlikely the carditis cases are related to the vaccine,” he said. And that “plausibly implies a specific underlying mechanism between vaccination and carditis that may only be applicable to mRNA vaccines.”

That inference is in line with case reports and other research, including large population-based studies from Israel and Denmark, although a recent study from the United Kingdom hinted at a potential excess myocarditis risk associated with the adenovirus-based AstraZeneca-Oxford vaccine.

The Hong Kong study identified 160 patients age 12 or older with a first diagnosis of carditis during February to August 2021, in electronic health records covering nearly the entire region.

“We used laboratory test results of troponin levels to further eliminate unlikely cases of carditis,” Dr. Wong said. The health records were linked to a “population-based vaccination record” maintained by the government’s department of health.

About 10 control patients from among all hospitalized patients without carditis were matched by age, sex, and admission date to each of the 160 carditis cases. About 83% of cases and 92% of the controls were unvaccinated.

Among those who received the Pfizer-BioNTech vaccine, representing 12.5% of cases and 4.2% of controls, the estimated carditis incidence was 0.57 per 100,000 doses. For those who received CoronaVac, representing 4.4% of cases and 3.9% of controls, it was 0.31 per 100,000 doses.

In adjusted analysis, the odds ratios for carditis among Pfizer-BioNTech vaccine recipients, compared with unvaccinated controls, were 3.57 (95% confidence interval, 1.93-6.60) overall, 4.68 (95% CI, 2.25-9.71) for males, 2.22 (95% CI, 0.57-8.69) for females, 2.41 (95% CI, 1.18-4.90) for ages 18 and older, and 13.8 (95% CI, 2.86-110.4) for ages 12-17

Myocarditis accounted for most of the excess cases, with an overall OR of 9.29 (95% CI, 3.94-21.9). The OR reached only 1.06 (95% CI, 0.35-3.22) for pericarditis alone.

The case-control study is noteworthy for its design, which contrasts with the many recent case series and passive or active surveillance studies, and even the more robust population-based studies of vaccine-related myocarditis, observed Dongngan Truong, MD, University of Utah and Primary Children’s Hospital, both in Salt Lake City, who wasn’t part of the study.

Among its strengths, she said in an interview, are its linkage of comprehensive hospital and vaccination data sets for two different vaccines; and that it corroborates other research suggesting there is “something in particular about mRNA vaccination that seems to be associated with the development of myocarditis.”

Active surveillance in Israel

In an October 2021 report based on an Israeli Ministry of Health database covering up to May 2021, rates of myocarditis arising within 21 days of a second Pfizer-BioNTech dose in 16- to 19-year-olds reached about 1 per 6,637 males and 1 per 99,853 females. Those numbers compared with 1 per 26,000 males and 1 per 218,000 females across all age groups.

Now authors led by Dror Mevorach, MD, Hadassah Medical Center, Jerusalem, have published corresponding numbers from the same data base for myocarditis associated with the same vaccine in males and females aged 12-15.  

Their research covers 404,407 people in that age group who received a first dose of the mRNA-based vaccine and 326,463 who received the second dose from June to October, 2021. Only 18 cases of myocarditis were observed within 21 days of either dose.

The estimated rates for males were 0.56 cases per 100,000 after a first dose and 8.09 cases per 100,000 after a second dose.

For females, the estimates were 0 cases per 100,000 after a first dose and 0.69 cases per 100,000 after a second dose.

“The pattern observed, mainly following the second vaccination in males, suggests causality,” the group wrote.
 

Leveraging passive surveillance reports

Another new report adds a twist to updated numbers from the U.S. Vaccine Adverse Event Reporting System (VAERS).

Prevalences derived from the passive-surveillance data base, known for including case records of inconsistent quality or completeness, are considered especially prone to reporting bias, the authors acknowledged.

The current analysis, however, plunges deep into VAERS-reported cases of presumed SARS-CoV-2 vaccine-associated myocarditis to help clarify “more of the characteristics of the patients and some of the treatments and short-term outcomes,” Matthew E. Oster, MD, MPH, said in an interview.

Dr. Oster, from the Centers for Disease Control and Prevention and Emory University, Atlanta, is lead author on the study’s Jan. 25, 2022, publication in JAMA.

The group reviewed charts and interviewed involved clinicians to adjudicate and document presentations, therapies, and the clinical course of cases reported as SARS-CoV-2 vaccine–associated myocarditis from December 2020 to August 2021. Out of the nearly 2000 reports, which were limited to patients younger than 30, the group identified 1,626 likely cases of such myocarditis arising within 7 days of a second mRNA vaccine dose.

The confirmed cases consistently represented higher prevalences than expected compared with prepandemic myocarditis claims data for both sexes and across age groups spanning 12-29 years.

For example, rates were highest for adolescent males – about 106 and 71 cases per million second doses of the Pfizer-BioNTech vaccine in those aged 16-17 and 12-16, respectively, for example. They were lowest for women aged 25-29, at 2.23 cases per million second Pfizer-BioNTech doses; the highest rate among females was about 11 per million for the 16-17 age group.

The observed rates, Dr. Oster said, represent an update to VAERS numbers published June 2021 in Morbidity and Mortality Weekly Report covering cases through June 2021.

“Overall, the general risk of having myocarditis from the vaccines is still extremely low. Even in the highest risk groups, it is still extremely low, and still lower than the risk of having cardiac complications from COVID,” he noted.
 

How do patients fare clinically?

From their chart reviews and interviews with case clinicians, Dr. Oster said, “we started to learn quickly that this is really a different type of myocarditis.”

For example, its onset, typically within a few days of the potential immunologic cause, was more rapid than in viral myocarditis, and its symptoms resolved faster, the report notes. Clinical presentations tended to be less severe, treatments not as intensive, and outcomes not as serious, compared with “the kind of typical viral myocarditis that most of the providers were used to taking care of in the past,” he said. “The pattern for these cases was very consistent.”

The study covered VAERS reports of suspected myocarditis arising within a week of first dose of a mRNA-based vaccine from the United States launch of public vaccination in December 2020 to August 2021, the CDC-based group reported. By then, more than 192 million people in the country had received either the Pfizer-BioNTech (age 12 or older) or Moderna (age 18 or older) vaccines.

Of the 1,991 reports of myocarditis, including 391 also involving pericarditis, 1,626 met the study’s definition for myocarditis on adjudication; about 82% of the latter cases were in males.

Based on the investigators’ review of charts and clinician interviews connected with 826 cases that met their definition of myocarditis in patients younger than 30, 89% reported “chest pain, pressure, or discomfort” and 30% reported dyspnea or shortness of breath. Troponin levels were elevated in 98%, 72% of patients who underwent electrocardiography showed abnormalities, and 12% of those with echocardiography had left ventricular ejection fractions less than 50%.

About 96% were hospitalized, and presenting symptoms resolved by discharge in 87% of those with available data, the group noted. Among patients with data on in-hospital therapy, they wrote, NSAIDs were the most common therapy, in 87%.

‘Mild and self-limiting’

The case-control study from Hong Kong didn’t specifically examine patients’ treatment and clinical course, but it does portray their vaccine-associated myocarditis as contrasting with more familiar viral myocarditis.

Patients with “typical” myocarditis tend to be “overall much sicker than what we’re seeing with myocarditis following vaccination,” Dr. Truong agreed. None of the 20 patients with myocarditis after Pfizer-BioNTech vaccination in Hong Kong were admitted to the intensive care unit. That, she added, suggests none required extracorporeal membrane oxygenation or vasoactive support, often necessary in viral myocarditis. “And they had shorter hospital stays.”

In contrast, Dr. Wong noted, 14 of the study’s unvaccinated patients required ICU admission; 12 of them died during the follow-up period. None with vaccine-related carditis died during the study’s follow-up. “We also showed that cases following [Pfizer-BioNTech] vaccination were all mild and self-limiting.”

Dr. Truong largely agreed that SARS-CoV-2 vaccine myocarditis and most myocarditis seen before the pandemic can be viewed as distinct clinical entities, “at least in the short term. I think we do need to follow these patients to look at more long-term outcomes, because at this point I don’t think we know the long-term implications. But at least in the short term, it seems like these patients are different, are much less sick, and recover pretty quickly overall.”

Dr. Oster emphasized that the many and varied acute and long-term hazards from contracting COVID-19 far outweigh any risk for myocarditis from vaccination. But for individuals who were hit with myocarditis soon after their first mRNA vaccine dose, who have already established their susceptibility, he and his colleagues would recommend that they “consider alternatives and not get the vaccine again.”

Dr. Oster reported no relevant financial relationships. Dr. Wong and colleagues did not report any relevant disclosures. Dr. Truong has previously disclosed serving as a consultant to Pfizer.

A version of this article first appeared on Medscape.com.

Why some COVID-19 vaccines seem occasionally to cause a distinctive form of myocarditis, and why adolescent boys and young men appear most vulnerable, remain a mystery. But the entity’s prevalence, nuances of presentation, and likely clinical course have come into sharper view after recent additions to the literature.  

Two new publications all but confirm that the rare cases of myocarditis closely following vaccination against SARS-CoV-2, primarily with one of the mRNA-based vaccines from Pfizer-BioNTech and Moderna, is a clinically different creature from myocarditis physicians were likely to see before the pandemic.

A third report unveils rates of hospitalization for myocarditis linked to Pfizer-BioNTech vaccination in the 12- to 15-year age group, based on active surveillance across Israel. Of note, the rates were lower than corresponding numbers among the country’s 16- to 19-year-olds published in late 2021 by the same authors.
 

No link with CoronaVac

A case-control study covering almost the entire population of Hong Kong from February to August 2021 confirms a slight but significant excess risk for myocarditis and, to a lesser degree, pericarditis, after injections of the Pfizer-BioNTech vaccine. As consistently reported from other studies, the risks were highest in adolescent and young adult males and after a second dose.

The study estimated an overall carditis incidence of 5.7 cases per million doses of Pfizer-BioNTech, for a risk 3.5 times that in the unvaccinated Hong Kong population. Carditis rates after a first dose were about 2.5 per million and 10 per million after a second dose.

Hong Kong launched its public SARS-CoV-2 immunization program in late February 2021 with the Chinese-made CoronaVac (Sinovac) inactivated-virus vaccine, and introduced the mRNA-based alternative several weeks later. By August 2021, the vaccines had reached about 3.3 million people in the region – 49% of the Hong Kong population at least 12 years of age.

In a novel finding, there were no excesses in carditis cases after CoronaVac vaccination. The difference between vaccines likely isn’t caused by chance, because three-fourths of the carditis-associated Pfizer-BioNTech injections arose within a week, whereas “71% of cases following the use of CoronaVac occurred more than 30 days after vaccination,” senior author Ian Chi Kei Wong, PhD, University of Hong Kong, said in an interview.

“This onset distribution for cases having received CoronaVac demonstrates that it is highly unlikely the carditis cases are related to the vaccine,” he said. And that “plausibly implies a specific underlying mechanism between vaccination and carditis that may only be applicable to mRNA vaccines.”

That inference is in line with case reports and other research, including large population-based studies from Israel and Denmark, although a recent study from the United Kingdom hinted at a potential excess myocarditis risk associated with the adenovirus-based AstraZeneca-Oxford vaccine.

The Hong Kong study identified 160 patients age 12 or older with a first diagnosis of carditis during February to August 2021, in electronic health records covering nearly the entire region.

“We used laboratory test results of troponin levels to further eliminate unlikely cases of carditis,” Dr. Wong said. The health records were linked to a “population-based vaccination record” maintained by the government’s department of health.

About 10 control patients from among all hospitalized patients without carditis were matched by age, sex, and admission date to each of the 160 carditis cases. About 83% of cases and 92% of the controls were unvaccinated.

Among those who received the Pfizer-BioNTech vaccine, representing 12.5% of cases and 4.2% of controls, the estimated carditis incidence was 0.57 per 100,000 doses. For those who received CoronaVac, representing 4.4% of cases and 3.9% of controls, it was 0.31 per 100,000 doses.

In adjusted analysis, the odds ratios for carditis among Pfizer-BioNTech vaccine recipients, compared with unvaccinated controls, were 3.57 (95% confidence interval, 1.93-6.60) overall, 4.68 (95% CI, 2.25-9.71) for males, 2.22 (95% CI, 0.57-8.69) for females, 2.41 (95% CI, 1.18-4.90) for ages 18 and older, and 13.8 (95% CI, 2.86-110.4) for ages 12-17

Myocarditis accounted for most of the excess cases, with an overall OR of 9.29 (95% CI, 3.94-21.9). The OR reached only 1.06 (95% CI, 0.35-3.22) for pericarditis alone.

The case-control study is noteworthy for its design, which contrasts with the many recent case series and passive or active surveillance studies, and even the more robust population-based studies of vaccine-related myocarditis, observed Dongngan Truong, MD, University of Utah and Primary Children’s Hospital, both in Salt Lake City, who wasn’t part of the study.

Among its strengths, she said in an interview, are its linkage of comprehensive hospital and vaccination data sets for two different vaccines; and that it corroborates other research suggesting there is “something in particular about mRNA vaccination that seems to be associated with the development of myocarditis.”

Active surveillance in Israel

In an October 2021 report based on an Israeli Ministry of Health database covering up to May 2021, rates of myocarditis arising within 21 days of a second Pfizer-BioNTech dose in 16- to 19-year-olds reached about 1 per 6,637 males and 1 per 99,853 females. Those numbers compared with 1 per 26,000 males and 1 per 218,000 females across all age groups.

Now authors led by Dror Mevorach, MD, Hadassah Medical Center, Jerusalem, have published corresponding numbers from the same data base for myocarditis associated with the same vaccine in males and females aged 12-15.  

Their research covers 404,407 people in that age group who received a first dose of the mRNA-based vaccine and 326,463 who received the second dose from June to October, 2021. Only 18 cases of myocarditis were observed within 21 days of either dose.

The estimated rates for males were 0.56 cases per 100,000 after a first dose and 8.09 cases per 100,000 after a second dose.

For females, the estimates were 0 cases per 100,000 after a first dose and 0.69 cases per 100,000 after a second dose.

“The pattern observed, mainly following the second vaccination in males, suggests causality,” the group wrote.
 

Leveraging passive surveillance reports

Another new report adds a twist to updated numbers from the U.S. Vaccine Adverse Event Reporting System (VAERS).

Prevalences derived from the passive-surveillance data base, known for including case records of inconsistent quality or completeness, are considered especially prone to reporting bias, the authors acknowledged.

The current analysis, however, plunges deep into VAERS-reported cases of presumed SARS-CoV-2 vaccine-associated myocarditis to help clarify “more of the characteristics of the patients and some of the treatments and short-term outcomes,” Matthew E. Oster, MD, MPH, said in an interview.

Dr. Oster, from the Centers for Disease Control and Prevention and Emory University, Atlanta, is lead author on the study’s Jan. 25, 2022, publication in JAMA.

The group reviewed charts and interviewed involved clinicians to adjudicate and document presentations, therapies, and the clinical course of cases reported as SARS-CoV-2 vaccine–associated myocarditis from December 2020 to August 2021. Out of the nearly 2000 reports, which were limited to patients younger than 30, the group identified 1,626 likely cases of such myocarditis arising within 7 days of a second mRNA vaccine dose.

The confirmed cases consistently represented higher prevalences than expected compared with prepandemic myocarditis claims data for both sexes and across age groups spanning 12-29 years.

For example, rates were highest for adolescent males – about 106 and 71 cases per million second doses of the Pfizer-BioNTech vaccine in those aged 16-17 and 12-16, respectively, for example. They were lowest for women aged 25-29, at 2.23 cases per million second Pfizer-BioNTech doses; the highest rate among females was about 11 per million for the 16-17 age group.

The observed rates, Dr. Oster said, represent an update to VAERS numbers published June 2021 in Morbidity and Mortality Weekly Report covering cases through June 2021.

“Overall, the general risk of having myocarditis from the vaccines is still extremely low. Even in the highest risk groups, it is still extremely low, and still lower than the risk of having cardiac complications from COVID,” he noted.
 

How do patients fare clinically?

From their chart reviews and interviews with case clinicians, Dr. Oster said, “we started to learn quickly that this is really a different type of myocarditis.”

For example, its onset, typically within a few days of the potential immunologic cause, was more rapid than in viral myocarditis, and its symptoms resolved faster, the report notes. Clinical presentations tended to be less severe, treatments not as intensive, and outcomes not as serious, compared with “the kind of typical viral myocarditis that most of the providers were used to taking care of in the past,” he said. “The pattern for these cases was very consistent.”

The study covered VAERS reports of suspected myocarditis arising within a week of first dose of a mRNA-based vaccine from the United States launch of public vaccination in December 2020 to August 2021, the CDC-based group reported. By then, more than 192 million people in the country had received either the Pfizer-BioNTech (age 12 or older) or Moderna (age 18 or older) vaccines.

Of the 1,991 reports of myocarditis, including 391 also involving pericarditis, 1,626 met the study’s definition for myocarditis on adjudication; about 82% of the latter cases were in males.

Based on the investigators’ review of charts and clinician interviews connected with 826 cases that met their definition of myocarditis in patients younger than 30, 89% reported “chest pain, pressure, or discomfort” and 30% reported dyspnea or shortness of breath. Troponin levels were elevated in 98%, 72% of patients who underwent electrocardiography showed abnormalities, and 12% of those with echocardiography had left ventricular ejection fractions less than 50%.

About 96% were hospitalized, and presenting symptoms resolved by discharge in 87% of those with available data, the group noted. Among patients with data on in-hospital therapy, they wrote, NSAIDs were the most common therapy, in 87%.

‘Mild and self-limiting’

The case-control study from Hong Kong didn’t specifically examine patients’ treatment and clinical course, but it does portray their vaccine-associated myocarditis as contrasting with more familiar viral myocarditis.

Patients with “typical” myocarditis tend to be “overall much sicker than what we’re seeing with myocarditis following vaccination,” Dr. Truong agreed. None of the 20 patients with myocarditis after Pfizer-BioNTech vaccination in Hong Kong were admitted to the intensive care unit. That, she added, suggests none required extracorporeal membrane oxygenation or vasoactive support, often necessary in viral myocarditis. “And they had shorter hospital stays.”

In contrast, Dr. Wong noted, 14 of the study’s unvaccinated patients required ICU admission; 12 of them died during the follow-up period. None with vaccine-related carditis died during the study’s follow-up. “We also showed that cases following [Pfizer-BioNTech] vaccination were all mild and self-limiting.”

Dr. Truong largely agreed that SARS-CoV-2 vaccine myocarditis and most myocarditis seen before the pandemic can be viewed as distinct clinical entities, “at least in the short term. I think we do need to follow these patients to look at more long-term outcomes, because at this point I don’t think we know the long-term implications. But at least in the short term, it seems like these patients are different, are much less sick, and recover pretty quickly overall.”

Dr. Oster emphasized that the many and varied acute and long-term hazards from contracting COVID-19 far outweigh any risk for myocarditis from vaccination. But for individuals who were hit with myocarditis soon after their first mRNA vaccine dose, who have already established their susceptibility, he and his colleagues would recommend that they “consider alternatives and not get the vaccine again.”

Dr. Oster reported no relevant financial relationships. Dr. Wong and colleagues did not report any relevant disclosures. Dr. Truong has previously disclosed serving as a consultant to Pfizer.

A version of this article first appeared on Medscape.com.

Why some COVID-19 vaccines seem occasionally to cause a distinctive form of myocarditis, and why adolescent boys and young men appear most vulnerable, remain a mystery. But the entity’s prevalence, nuances of presentation, and likely clinical course have come into sharper view after recent additions to the literature.  

Two new publications all but confirm that the rare cases of myocarditis closely following vaccination against SARS-CoV-2, primarily with one of the mRNA-based vaccines from Pfizer-BioNTech and Moderna, is a clinically different creature from myocarditis physicians were likely to see before the pandemic.

A third report unveils rates of hospitalization for myocarditis linked to Pfizer-BioNTech vaccination in the 12- to 15-year age group, based on active surveillance across Israel. Of note, the rates were lower than corresponding numbers among the country’s 16- to 19-year-olds published in late 2021 by the same authors.
 

No link with CoronaVac

A case-control study covering almost the entire population of Hong Kong from February to August 2021 confirms a slight but significant excess risk for myocarditis and, to a lesser degree, pericarditis, after injections of the Pfizer-BioNTech vaccine. As consistently reported from other studies, the risks were highest in adolescent and young adult males and after a second dose.

The study estimated an overall carditis incidence of 5.7 cases per million doses of Pfizer-BioNTech, for a risk 3.5 times that in the unvaccinated Hong Kong population. Carditis rates after a first dose were about 2.5 per million and 10 per million after a second dose.

Hong Kong launched its public SARS-CoV-2 immunization program in late February 2021 with the Chinese-made CoronaVac (Sinovac) inactivated-virus vaccine, and introduced the mRNA-based alternative several weeks later. By August 2021, the vaccines had reached about 3.3 million people in the region – 49% of the Hong Kong population at least 12 years of age.

In a novel finding, there were no excesses in carditis cases after CoronaVac vaccination. The difference between vaccines likely isn’t caused by chance, because three-fourths of the carditis-associated Pfizer-BioNTech injections arose within a week, whereas “71% of cases following the use of CoronaVac occurred more than 30 days after vaccination,” senior author Ian Chi Kei Wong, PhD, University of Hong Kong, said in an interview.

“This onset distribution for cases having received CoronaVac demonstrates that it is highly unlikely the carditis cases are related to the vaccine,” he said. And that “plausibly implies a specific underlying mechanism between vaccination and carditis that may only be applicable to mRNA vaccines.”

That inference is in line with case reports and other research, including large population-based studies from Israel and Denmark, although a recent study from the United Kingdom hinted at a potential excess myocarditis risk associated with the adenovirus-based AstraZeneca-Oxford vaccine.

The Hong Kong study identified 160 patients age 12 or older with a first diagnosis of carditis during February to August 2021, in electronic health records covering nearly the entire region.

“We used laboratory test results of troponin levels to further eliminate unlikely cases of carditis,” Dr. Wong said. The health records were linked to a “population-based vaccination record” maintained by the government’s department of health.

About 10 control patients from among all hospitalized patients without carditis were matched by age, sex, and admission date to each of the 160 carditis cases. About 83% of cases and 92% of the controls were unvaccinated.

Among those who received the Pfizer-BioNTech vaccine, representing 12.5% of cases and 4.2% of controls, the estimated carditis incidence was 0.57 per 100,000 doses. For those who received CoronaVac, representing 4.4% of cases and 3.9% of controls, it was 0.31 per 100,000 doses.

In adjusted analysis, the odds ratios for carditis among Pfizer-BioNTech vaccine recipients, compared with unvaccinated controls, were 3.57 (95% confidence interval, 1.93-6.60) overall, 4.68 (95% CI, 2.25-9.71) for males, 2.22 (95% CI, 0.57-8.69) for females, 2.41 (95% CI, 1.18-4.90) for ages 18 and older, and 13.8 (95% CI, 2.86-110.4) for ages 12-17

Myocarditis accounted for most of the excess cases, with an overall OR of 9.29 (95% CI, 3.94-21.9). The OR reached only 1.06 (95% CI, 0.35-3.22) for pericarditis alone.

The case-control study is noteworthy for its design, which contrasts with the many recent case series and passive or active surveillance studies, and even the more robust population-based studies of vaccine-related myocarditis, observed Dongngan Truong, MD, University of Utah and Primary Children’s Hospital, both in Salt Lake City, who wasn’t part of the study.

Among its strengths, she said in an interview, are its linkage of comprehensive hospital and vaccination data sets for two different vaccines; and that it corroborates other research suggesting there is “something in particular about mRNA vaccination that seems to be associated with the development of myocarditis.”

Active surveillance in Israel

In an October 2021 report based on an Israeli Ministry of Health database covering up to May 2021, rates of myocarditis arising within 21 days of a second Pfizer-BioNTech dose in 16- to 19-year-olds reached about 1 per 6,637 males and 1 per 99,853 females. Those numbers compared with 1 per 26,000 males and 1 per 218,000 females across all age groups.

Now authors led by Dror Mevorach, MD, Hadassah Medical Center, Jerusalem, have published corresponding numbers from the same data base for myocarditis associated with the same vaccine in males and females aged 12-15.  

Their research covers 404,407 people in that age group who received a first dose of the mRNA-based vaccine and 326,463 who received the second dose from June to October, 2021. Only 18 cases of myocarditis were observed within 21 days of either dose.

The estimated rates for males were 0.56 cases per 100,000 after a first dose and 8.09 cases per 100,000 after a second dose.

For females, the estimates were 0 cases per 100,000 after a first dose and 0.69 cases per 100,000 after a second dose.

“The pattern observed, mainly following the second vaccination in males, suggests causality,” the group wrote.
 

Leveraging passive surveillance reports

Another new report adds a twist to updated numbers from the U.S. Vaccine Adverse Event Reporting System (VAERS).

Prevalences derived from the passive-surveillance data base, known for including case records of inconsistent quality or completeness, are considered especially prone to reporting bias, the authors acknowledged.

The current analysis, however, plunges deep into VAERS-reported cases of presumed SARS-CoV-2 vaccine-associated myocarditis to help clarify “more of the characteristics of the patients and some of the treatments and short-term outcomes,” Matthew E. Oster, MD, MPH, said in an interview.

Dr. Oster, from the Centers for Disease Control and Prevention and Emory University, Atlanta, is lead author on the study’s Jan. 25, 2022, publication in JAMA.

The group reviewed charts and interviewed involved clinicians to adjudicate and document presentations, therapies, and the clinical course of cases reported as SARS-CoV-2 vaccine–associated myocarditis from December 2020 to August 2021. Out of the nearly 2000 reports, which were limited to patients younger than 30, the group identified 1,626 likely cases of such myocarditis arising within 7 days of a second mRNA vaccine dose.

The confirmed cases consistently represented higher prevalences than expected compared with prepandemic myocarditis claims data for both sexes and across age groups spanning 12-29 years.

For example, rates were highest for adolescent males – about 106 and 71 cases per million second doses of the Pfizer-BioNTech vaccine in those aged 16-17 and 12-16, respectively, for example. They were lowest for women aged 25-29, at 2.23 cases per million second Pfizer-BioNTech doses; the highest rate among females was about 11 per million for the 16-17 age group.

The observed rates, Dr. Oster said, represent an update to VAERS numbers published June 2021 in Morbidity and Mortality Weekly Report covering cases through June 2021.

“Overall, the general risk of having myocarditis from the vaccines is still extremely low. Even in the highest risk groups, it is still extremely low, and still lower than the risk of having cardiac complications from COVID,” he noted.
 

How do patients fare clinically?

From their chart reviews and interviews with case clinicians, Dr. Oster said, “we started to learn quickly that this is really a different type of myocarditis.”

For example, its onset, typically within a few days of the potential immunologic cause, was more rapid than in viral myocarditis, and its symptoms resolved faster, the report notes. Clinical presentations tended to be less severe, treatments not as intensive, and outcomes not as serious, compared with “the kind of typical viral myocarditis that most of the providers were used to taking care of in the past,” he said. “The pattern for these cases was very consistent.”

The study covered VAERS reports of suspected myocarditis arising within a week of first dose of a mRNA-based vaccine from the United States launch of public vaccination in December 2020 to August 2021, the CDC-based group reported. By then, more than 192 million people in the country had received either the Pfizer-BioNTech (age 12 or older) or Moderna (age 18 or older) vaccines.

Of the 1,991 reports of myocarditis, including 391 also involving pericarditis, 1,626 met the study’s definition for myocarditis on adjudication; about 82% of the latter cases were in males.

Based on the investigators’ review of charts and clinician interviews connected with 826 cases that met their definition of myocarditis in patients younger than 30, 89% reported “chest pain, pressure, or discomfort” and 30% reported dyspnea or shortness of breath. Troponin levels were elevated in 98%, 72% of patients who underwent electrocardiography showed abnormalities, and 12% of those with echocardiography had left ventricular ejection fractions less than 50%.

About 96% were hospitalized, and presenting symptoms resolved by discharge in 87% of those with available data, the group noted. Among patients with data on in-hospital therapy, they wrote, NSAIDs were the most common therapy, in 87%.

‘Mild and self-limiting’

The case-control study from Hong Kong didn’t specifically examine patients’ treatment and clinical course, but it does portray their vaccine-associated myocarditis as contrasting with more familiar viral myocarditis.

Patients with “typical” myocarditis tend to be “overall much sicker than what we’re seeing with myocarditis following vaccination,” Dr. Truong agreed. None of the 20 patients with myocarditis after Pfizer-BioNTech vaccination in Hong Kong were admitted to the intensive care unit. That, she added, suggests none required extracorporeal membrane oxygenation or vasoactive support, often necessary in viral myocarditis. “And they had shorter hospital stays.”

In contrast, Dr. Wong noted, 14 of the study’s unvaccinated patients required ICU admission; 12 of them died during the follow-up period. None with vaccine-related carditis died during the study’s follow-up. “We also showed that cases following [Pfizer-BioNTech] vaccination were all mild and self-limiting.”

Dr. Truong largely agreed that SARS-CoV-2 vaccine myocarditis and most myocarditis seen before the pandemic can be viewed as distinct clinical entities, “at least in the short term. I think we do need to follow these patients to look at more long-term outcomes, because at this point I don’t think we know the long-term implications. But at least in the short term, it seems like these patients are different, are much less sick, and recover pretty quickly overall.”

Dr. Oster emphasized that the many and varied acute and long-term hazards from contracting COVID-19 far outweigh any risk for myocarditis from vaccination. But for individuals who were hit with myocarditis soon after their first mRNA vaccine dose, who have already established their susceptibility, he and his colleagues would recommend that they “consider alternatives and not get the vaccine again.”

Dr. Oster reported no relevant financial relationships. Dr. Wong and colleagues did not report any relevant disclosures. Dr. Truong has previously disclosed serving as a consultant to Pfizer.

A version of this article first appeared on Medscape.com.

There’s overall agreement that iron deficiency is prevalent and portends a worse prognosis in patients with heart failure (HF), regardless of ejection fraction or anemia. What remains unclear, however, is which of the many definitions of iron deficiency most closely aligns with adverse outcomes.

Iron deficiency (ID) differs in chronic inflammatory conditions, such as chronic HF, and is defined in international guidelines as a ferritin less than 100 ng/mL or ferritin 100-299 ng/mL with a transferrin saturation (TSAT) less than 20%.

copyrightSaipg/iStockphoto

A new study examining four definitions of ID in more than 4,000 patients with HF revealed that TSAT and serum iron – but not guideline criteria – were independently associated with higher 5-year all-cause mortality, regardless of HF phenotype.

“The standard definition, the society guideline definition of iron deficiency, simply isn’t related to outcome at all. The lines for mortality are, more or less, superimposed,” senior author Andrew L. Clark, MD, Hull (England) University Teaching Hospital NHS Trust, told this news organization.

“So we do think, therefore, there’s a need for a rethink as to what constitutes a definition of iron definition in people with heart failure.”

The results were published in the Journal of the American College of Cardiology.

Previous studies have shown that guideline-defined ID is an independent predictor of mortality in chronic HF, but others have questioned its diagnostic and prognostic utility. A 2018 study using bone marrow iron staining as the gold standard showed that a TSAT of 19.8% or less or serum iron of 13 mcmol/L or less, but not ferritin, identified HF patients at the highest risk for death.

A 2016 report from the Hull LifeLab cohort also showed that the highest quintiles of ferritin had the worst all-cause and cardiovascular (CV) mortality.

Commenting on the new results, Maria Rosa Costanzo, MD, Midwest Cardiovascular Institute, Naperville, Ill., said “the first clinical implication is that we should not use these guidelines to define iron deficiency.

“The fundamental problem with the definition is that ferritin is not a good marker of iron deficiency because ferritin is an inflammatory marker,” she said. “So you could have high ferritin and still have iron deficiency because heart failure, like many other diseases, is an inflammatory state.”

In the present analysis of 4,422 patients referred to the Hull LifeLab clinic between 2001 and 2019, iron deficiency was defined using international guideline criteria, ferritin less than 100 ng/mL, TSAT less than 20%, and serum iron 13 mcmol/L or less.

In line with previous studies, the prevalence of ID was high, ranging from 44% to 68%, depending on the definition. ID was more common in women and in those with more severe symptoms, anemia, or preserved ejection fraction.

Overall, 5-year mortality was 34.5% (median follow-up, 49 months). Unadjusted mortality was lowest for patients with a serum ferritin less than 100 ng/mL and a TSAT greater than 20% and was highest for those with serum ferritin above 100 ng/mL with a TSAT less than 20%.

Serum iron levels and TSAT were highly correlated with each other (r = 0.92; P < .001). “Serum iron is almost entirely transferrin bound, and therefore a close association between serious iron and TSAT is not surprising,” noted the authors, led by Gabriele Masini, MD, University of Brescia (Italy).

After multivariate adjustment, TSAT less than 20% (hazard ratio, 1.27; P < .001) and serum iron of 13 mcmol/L or less (HR, 1.37; P < .001) were associated with greater all-cause mortality but not with CV mortality.

Serum ferritin less than 100 ng/mL tended to be associated with lower adjusted all-cause mortality (HR, 0.91; P = .09), whereas ferritin greater than 300 ng/mL was associated with lower all-cause (HR, 0.69, P < .001) and CV mortality (HR, 0.78; P = .048).

No association was found for guideline ID criteria and all-cause or CV mortality. Among patients fulfilling guideline ID criteria with a TSAT less than 20% and a ferritin 100 to 299 ng/mL, the adjusted hazard ratio for 5-year mortality was 1.82.
 

A ‘new iron age’

Although 3,011 (68%) patients met the guideline definition of ID, 32% of these patients had a TSAT of 20% or greater and serum iron above 13 mcmol/L, noted Dr. Costanzo.

“In other words, 30% of the patients do not have true iron deficiency,” she said. “If these patients are enrolled in trials of treatment for iron deficiency, they may spuriously reduce the efficacy of treatment.”

Intravenous iron has been shown to improve exercise capacity and quality of life in iron-deficient patients with HF in a series of trials, including FAIR-HF, CONFIRM-HF, and EFFECT-HF, and to reduce HF hospitalizations by 21% in the recent AFFIRM-AF trial.

Although from a single center, Dr. Clark said their findings are robust and hoped they spur a reanalysis of the data from older intravenous iron trials, as well as the IRONMAN trial expected later this year in patients with TSAT less than 20% or ferritin less than 100 ng/L.

“I would very much like to encourage industry to take our study and run with it a little bit and see if we can actually persuade them to rerun studies, maybe even very small-scale studies with a couple hundred patients, to see what the signal is using our definition of iron deficiency and seeing if we get a more striking immediate consequence from IV iron treatment as a result,” he said. “Because we think that we’ve now been able to define a group of patients whose iron deficiency is giving them a very poor prognosis and they, therefore, have much more to gain.”

In an accompanying editorial, Dr. Costanzo and coauthor James Januzzi, MD, of Massachusetts General Hospital and Harvard Medical School, both in Boston, also called for further research into better ID definitions and treatments.

“Diagnostically, soluble transferrin receptor levels may have the strongest correlation with the gold standard of bone marrow iron deficit, whereas new treatments, such as blockade of hepcidin, a key modulator of iron absorption and distribution, may emerge as an effective treatment for both absolute and functional ID,” they wrote.

“Ultimately, the study by Masini et al. places us squarely in a new iron age and underscores the great need for more investigation of the pathophysiology, clinical consequences, and treatment of iron deficiency in all patients with HF,” Dr. Costanzo and Dr. Januzzi concluded.

Dr. Masini reported having no relevant financial relationships. Dr. Januzzi is supported by the Hutter Family Professorship; is a trustee of the American College of Cardiology; is a board member of Imbria Pharmaceuticals; has received grant support from Abbott Diagnostics, Applied Therapeutics, Innolife, and Novartis; has received consulting income from Abbott Diagnostics, Boehringer Ingelheim, Janssen, Novartis, and Roche Diagnostics; and participates in clinical endpoint committees/data safety monitoring boards for AbbVie, Siemens, Takeda, and Vifor. Dr. Costanzo is a member of the board of directors for Nuwellis; is a consultant for Boehringer Ingelheim, V-Wave, and Nuwellis; and has received grant support from Novartis, Bayer, V-Wave, Nuwellis, and Abbott.

A version of this article first appeared on Medscape.com.

There’s overall agreement that iron deficiency is prevalent and portends a worse prognosis in patients with heart failure (HF), regardless of ejection fraction or anemia. What remains unclear, however, is which of the many definitions of iron deficiency most closely aligns with adverse outcomes.

Iron deficiency (ID) differs in chronic inflammatory conditions, such as chronic HF, and is defined in international guidelines as a ferritin less than 100 ng/mL or ferritin 100-299 ng/mL with a transferrin saturation (TSAT) less than 20%.

copyrightSaipg/iStockphoto

A new study examining four definitions of ID in more than 4,000 patients with HF revealed that TSAT and serum iron – but not guideline criteria – were independently associated with higher 5-year all-cause mortality, regardless of HF phenotype.

“The standard definition, the society guideline definition of iron deficiency, simply isn’t related to outcome at all. The lines for mortality are, more or less, superimposed,” senior author Andrew L. Clark, MD, Hull (England) University Teaching Hospital NHS Trust, told this news organization.

“So we do think, therefore, there’s a need for a rethink as to what constitutes a definition of iron definition in people with heart failure.”

The results were published in the Journal of the American College of Cardiology.

Previous studies have shown that guideline-defined ID is an independent predictor of mortality in chronic HF, but others have questioned its diagnostic and prognostic utility. A 2018 study using bone marrow iron staining as the gold standard showed that a TSAT of 19.8% or less or serum iron of 13 mcmol/L or less, but not ferritin, identified HF patients at the highest risk for death.

A 2016 report from the Hull LifeLab cohort also showed that the highest quintiles of ferritin had the worst all-cause and cardiovascular (CV) mortality.

Commenting on the new results, Maria Rosa Costanzo, MD, Midwest Cardiovascular Institute, Naperville, Ill., said “the first clinical implication is that we should not use these guidelines to define iron deficiency.

“The fundamental problem with the definition is that ferritin is not a good marker of iron deficiency because ferritin is an inflammatory marker,” she said. “So you could have high ferritin and still have iron deficiency because heart failure, like many other diseases, is an inflammatory state.”

In the present analysis of 4,422 patients referred to the Hull LifeLab clinic between 2001 and 2019, iron deficiency was defined using international guideline criteria, ferritin less than 100 ng/mL, TSAT less than 20%, and serum iron 13 mcmol/L or less.

In line with previous studies, the prevalence of ID was high, ranging from 44% to 68%, depending on the definition. ID was more common in women and in those with more severe symptoms, anemia, or preserved ejection fraction.

Overall, 5-year mortality was 34.5% (median follow-up, 49 months). Unadjusted mortality was lowest for patients with a serum ferritin less than 100 ng/mL and a TSAT greater than 20% and was highest for those with serum ferritin above 100 ng/mL with a TSAT less than 20%.

Serum iron levels and TSAT were highly correlated with each other (r = 0.92; P < .001). “Serum iron is almost entirely transferrin bound, and therefore a close association between serious iron and TSAT is not surprising,” noted the authors, led by Gabriele Masini, MD, University of Brescia (Italy).

After multivariate adjustment, TSAT less than 20% (hazard ratio, 1.27; P < .001) and serum iron of 13 mcmol/L or less (HR, 1.37; P < .001) were associated with greater all-cause mortality but not with CV mortality.

Serum ferritin less than 100 ng/mL tended to be associated with lower adjusted all-cause mortality (HR, 0.91; P = .09), whereas ferritin greater than 300 ng/mL was associated with lower all-cause (HR, 0.69, P < .001) and CV mortality (HR, 0.78; P = .048).

No association was found for guideline ID criteria and all-cause or CV mortality. Among patients fulfilling guideline ID criteria with a TSAT less than 20% and a ferritin 100 to 299 ng/mL, the adjusted hazard ratio for 5-year mortality was 1.82.
 

A ‘new iron age’

Although 3,011 (68%) patients met the guideline definition of ID, 32% of these patients had a TSAT of 20% or greater and serum iron above 13 mcmol/L, noted Dr. Costanzo.

“In other words, 30% of the patients do not have true iron deficiency,” she said. “If these patients are enrolled in trials of treatment for iron deficiency, they may spuriously reduce the efficacy of treatment.”

Intravenous iron has been shown to improve exercise capacity and quality of life in iron-deficient patients with HF in a series of trials, including FAIR-HF, CONFIRM-HF, and EFFECT-HF, and to reduce HF hospitalizations by 21% in the recent AFFIRM-AF trial.

Although from a single center, Dr. Clark said their findings are robust and hoped they spur a reanalysis of the data from older intravenous iron trials, as well as the IRONMAN trial expected later this year in patients with TSAT less than 20% or ferritin less than 100 ng/L.

“I would very much like to encourage industry to take our study and run with it a little bit and see if we can actually persuade them to rerun studies, maybe even very small-scale studies with a couple hundred patients, to see what the signal is using our definition of iron deficiency and seeing if we get a more striking immediate consequence from IV iron treatment as a result,” he said. “Because we think that we’ve now been able to define a group of patients whose iron deficiency is giving them a very poor prognosis and they, therefore, have much more to gain.”

In an accompanying editorial, Dr. Costanzo and coauthor James Januzzi, MD, of Massachusetts General Hospital and Harvard Medical School, both in Boston, also called for further research into better ID definitions and treatments.

“Diagnostically, soluble transferrin receptor levels may have the strongest correlation with the gold standard of bone marrow iron deficit, whereas new treatments, such as blockade of hepcidin, a key modulator of iron absorption and distribution, may emerge as an effective treatment for both absolute and functional ID,” they wrote.

“Ultimately, the study by Masini et al. places us squarely in a new iron age and underscores the great need for more investigation of the pathophysiology, clinical consequences, and treatment of iron deficiency in all patients with HF,” Dr. Costanzo and Dr. Januzzi concluded.

Dr. Masini reported having no relevant financial relationships. Dr. Januzzi is supported by the Hutter Family Professorship; is a trustee of the American College of Cardiology; is a board member of Imbria Pharmaceuticals; has received grant support from Abbott Diagnostics, Applied Therapeutics, Innolife, and Novartis; has received consulting income from Abbott Diagnostics, Boehringer Ingelheim, Janssen, Novartis, and Roche Diagnostics; and participates in clinical endpoint committees/data safety monitoring boards for AbbVie, Siemens, Takeda, and Vifor. Dr. Costanzo is a member of the board of directors for Nuwellis; is a consultant for Boehringer Ingelheim, V-Wave, and Nuwellis; and has received grant support from Novartis, Bayer, V-Wave, Nuwellis, and Abbott.

A version of this article first appeared on Medscape.com.

There’s overall agreement that iron deficiency is prevalent and portends a worse prognosis in patients with heart failure (HF), regardless of ejection fraction or anemia. What remains unclear, however, is which of the many definitions of iron deficiency most closely aligns with adverse outcomes.

Iron deficiency (ID) differs in chronic inflammatory conditions, such as chronic HF, and is defined in international guidelines as a ferritin less than 100 ng/mL or ferritin 100-299 ng/mL with a transferrin saturation (TSAT) less than 20%.

copyrightSaipg/iStockphoto

A new study examining four definitions of ID in more than 4,000 patients with HF revealed that TSAT and serum iron – but not guideline criteria – were independently associated with higher 5-year all-cause mortality, regardless of HF phenotype.

“The standard definition, the society guideline definition of iron deficiency, simply isn’t related to outcome at all. The lines for mortality are, more or less, superimposed,” senior author Andrew L. Clark, MD, Hull (England) University Teaching Hospital NHS Trust, told this news organization.

“So we do think, therefore, there’s a need for a rethink as to what constitutes a definition of iron definition in people with heart failure.”

The results were published in the Journal of the American College of Cardiology.

Previous studies have shown that guideline-defined ID is an independent predictor of mortality in chronic HF, but others have questioned its diagnostic and prognostic utility. A 2018 study using bone marrow iron staining as the gold standard showed that a TSAT of 19.8% or less or serum iron of 13 mcmol/L or less, but not ferritin, identified HF patients at the highest risk for death.

A 2016 report from the Hull LifeLab cohort also showed that the highest quintiles of ferritin had the worst all-cause and cardiovascular (CV) mortality.

Commenting on the new results, Maria Rosa Costanzo, MD, Midwest Cardiovascular Institute, Naperville, Ill., said “the first clinical implication is that we should not use these guidelines to define iron deficiency.

“The fundamental problem with the definition is that ferritin is not a good marker of iron deficiency because ferritin is an inflammatory marker,” she said. “So you could have high ferritin and still have iron deficiency because heart failure, like many other diseases, is an inflammatory state.”

In the present analysis of 4,422 patients referred to the Hull LifeLab clinic between 2001 and 2019, iron deficiency was defined using international guideline criteria, ferritin less than 100 ng/mL, TSAT less than 20%, and serum iron 13 mcmol/L or less.

In line with previous studies, the prevalence of ID was high, ranging from 44% to 68%, depending on the definition. ID was more common in women and in those with more severe symptoms, anemia, or preserved ejection fraction.

Overall, 5-year mortality was 34.5% (median follow-up, 49 months). Unadjusted mortality was lowest for patients with a serum ferritin less than 100 ng/mL and a TSAT greater than 20% and was highest for those with serum ferritin above 100 ng/mL with a TSAT less than 20%.

Serum iron levels and TSAT were highly correlated with each other (r = 0.92; P < .001). “Serum iron is almost entirely transferrin bound, and therefore a close association between serious iron and TSAT is not surprising,” noted the authors, led by Gabriele Masini, MD, University of Brescia (Italy).

After multivariate adjustment, TSAT less than 20% (hazard ratio, 1.27; P < .001) and serum iron of 13 mcmol/L or less (HR, 1.37; P < .001) were associated with greater all-cause mortality but not with CV mortality.

Serum ferritin less than 100 ng/mL tended to be associated with lower adjusted all-cause mortality (HR, 0.91; P = .09), whereas ferritin greater than 300 ng/mL was associated with lower all-cause (HR, 0.69, P < .001) and CV mortality (HR, 0.78; P = .048).

No association was found for guideline ID criteria and all-cause or CV mortality. Among patients fulfilling guideline ID criteria with a TSAT less than 20% and a ferritin 100 to 299 ng/mL, the adjusted hazard ratio for 5-year mortality was 1.82.
 

A ‘new iron age’

Although 3,011 (68%) patients met the guideline definition of ID, 32% of these patients had a TSAT of 20% or greater and serum iron above 13 mcmol/L, noted Dr. Costanzo.

“In other words, 30% of the patients do not have true iron deficiency,” she said. “If these patients are enrolled in trials of treatment for iron deficiency, they may spuriously reduce the efficacy of treatment.”

Intravenous iron has been shown to improve exercise capacity and quality of life in iron-deficient patients with HF in a series of trials, including FAIR-HF, CONFIRM-HF, and EFFECT-HF, and to reduce HF hospitalizations by 21% in the recent AFFIRM-AF trial.

Although from a single center, Dr. Clark said their findings are robust and hoped they spur a reanalysis of the data from older intravenous iron trials, as well as the IRONMAN trial expected later this year in patients with TSAT less than 20% or ferritin less than 100 ng/L.

“I would very much like to encourage industry to take our study and run with it a little bit and see if we can actually persuade them to rerun studies, maybe even very small-scale studies with a couple hundred patients, to see what the signal is using our definition of iron deficiency and seeing if we get a more striking immediate consequence from IV iron treatment as a result,” he said. “Because we think that we’ve now been able to define a group of patients whose iron deficiency is giving them a very poor prognosis and they, therefore, have much more to gain.”

In an accompanying editorial, Dr. Costanzo and coauthor James Januzzi, MD, of Massachusetts General Hospital and Harvard Medical School, both in Boston, also called for further research into better ID definitions and treatments.

“Diagnostically, soluble transferrin receptor levels may have the strongest correlation with the gold standard of bone marrow iron deficit, whereas new treatments, such as blockade of hepcidin, a key modulator of iron absorption and distribution, may emerge as an effective treatment for both absolute and functional ID,” they wrote.

“Ultimately, the study by Masini et al. places us squarely in a new iron age and underscores the great need for more investigation of the pathophysiology, clinical consequences, and treatment of iron deficiency in all patients with HF,” Dr. Costanzo and Dr. Januzzi concluded.

Dr. Masini reported having no relevant financial relationships. Dr. Januzzi is supported by the Hutter Family Professorship; is a trustee of the American College of Cardiology; is a board member of Imbria Pharmaceuticals; has received grant support from Abbott Diagnostics, Applied Therapeutics, Innolife, and Novartis; has received consulting income from Abbott Diagnostics, Boehringer Ingelheim, Janssen, Novartis, and Roche Diagnostics; and participates in clinical endpoint committees/data safety monitoring boards for AbbVie, Siemens, Takeda, and Vifor. Dr. Costanzo is a member of the board of directors for Nuwellis; is a consultant for Boehringer Ingelheim, V-Wave, and Nuwellis; and has received grant support from Novartis, Bayer, V-Wave, Nuwellis, and Abbott.

A version of this article first appeared on Medscape.com.

As inclisiran, a first-in-class LDL-cholesterol lowering drug, enters the U.S. market following Food and Drug Administration approval in December 2021, several issues muddy how popular inclisiran will be in actual practice. That’s despite stellar phase 3 trial evidence for safety, tolerability, and a potent lipid-lowering effect.

The active ingredient of inclisiran (Leqvio) is a small interfering RNA (siRNA) molecule that shuts down production of the PCSK9 (proprotein convertase subtilisin/kexin type 9) protein, an enzyme that’s made and functions primarily in the liver and degrades cellular receptors for LDL cholesterol. Inhibiting PCSK9 production means LDL-cholesterol receptors accumulate and boost the ability of liver cells to pull more LDL cholesterol out of blood.

PCSK9 inhibition is the most potent LDL-cholesterol lowering method now available, and it works well in patients who have maxed out LDL reduction by diet and statin treatment. The siRNA of inclisiran is tweaked to target the molecule to the surface of liver cells following subcutaneous injection. Other modifications of the siRNA give it stability that allows twice-a-year dosing, although patients receive a third injection during their first year to hasten a maximum treatment effect.

Inclisiran’s FDA approval relied on results from three pivotal trials that together enrolled 3,660 patients with either atherosclerotic cardiovascular disease (ASCVD), ASCVD risk equivalents, or heterozygous familial hypercholesterolemia (HeFH), and LDL-cholesterol levels of at least 70 mg/dL in those with established ASCVD, or at least 100 mg/dL in other patients. (HeFH and ASCVD are the drug’s approved indications.) Pooled data from the three trials showed that inclisiran was safe and well tolerated during 18 months and produced an average LDL-cholesterol reduction after 510 days (1.4 years) of about 51% compared to baseline after correction for placebo effects (J Am Coll Cardiol. 2021 Mar 9;77 [9]:1182-93).

These data showed inclisiran was about as safe and effective for reducing LDL-cholesterol as agents from another class of PCSK9 inhibitors that rely on injected antibodies to inactivate PCSK9. Two agents from this class, alirocumab (Praluent) and evolocumab (Repatha), both came on the U.S. market in 2015. Although their performance in routine practice during the ensuing 6-plus years has been as safe and effective as what they showed in their respective registration trials, they have faced a rocky uptake road that’s been primarily hindered by the hefty price tag that both drugs carry.
 

Prior-authorization blues

When they first came out, evolocumab and alirocumab were burdened by annual drug costs of roughly $14,000, a fact that led to widespread prior-authorization and copay barriers set up by U.S. insurers. Although these barriers gradually lessened over time, in part aided by a substantial price cut for both drugs that led to annual drug costs more in the range of $6,000/year, they remain relatively pricey and are still not easy to start in patients because of prior-authorization requirements, said clinicians.

Recent penetration of the older PCSK9 inhibitors into eligible U.S. patients “is only about 1%-2%, based on the latest data,” said Michael H. Davidson, MD, a lipid specialist and director of Preventive Cardiology at the University of Chicago.

“We have these great, effective drugs, but they haven’t really made an impact over the past 5 years,” because of very limited uptake, a situation Dr. Davidson called “very disappointing,” during an interview.

Given this recent history, inclisiran, another expensive PCSK9 inhibitor, may face similar coverage pushback as it hits the U.S. market with a retail price, announced by its manufacturer Novartis, of $3,250/dose. This means that patients who start the drug and receive their initial dose, a second dose after 3 months, and then additional doses every 6 months, rack up a drug cost of close to $10,000 the first year on the drug and $6,500 each subsequent year.

This treatment schedule highlights the major logistical difference that distinguishes inclisiran from the antibody-based PCSK9 inhibitors, which are given by repeated subcutaneous injection every 2 or 4 weeks, usually with patients self-injecting the drugs at home. The less-frequent dosing schedule for inclisiran prompted the drug’s developers to schedule injections by a clinician in an office setting in the pivotal trials, which led to labeling for inclisiran that specifies administration only by a health care professional.
 

The ‘buy-and-bill’ coverage model

This difference in drug administration between inclisiran and the antibody-based PCSK9 inhibitors set up Novartis to promote insurance reimbursement for inclisiran using a “buy-and-bill” paradigm that was first developed for oncology drugs and which may provide a loophole around the prior-authorization roadblocks that hindered early uptake of the antibody-based PCSK9 inhibitors.

It’s also an approach that has made U.S. clinicians unsure how it will play out in practice. Infrequent inclisiran dosing may also boost patient compliance.

“Adherence is the greatest challenge in preventive cardiology, and thus inclisiran has the potential to be a game changer,” commented Christie M. Ballantyne, MD, professor and chief of cardiology at Baylor College of Medicine, Houston.

“Will it be easier for physicians to write a prescription and for patients to get the medication without a demanding and frustrating prior-authorization process?” he wondered during an interview. “I’m waiting to see how this unfolds, especially in systems where pharmacy is not fully integrated with the outpatient setting. In some ways, this is as big of an experiment as was development of the drug,” Dr. Ballantyne said.

Although the prior-authorization hoops for evolocumab and alirocumab have become easier to jump through, “most physicians don’t have the resources to handle it and don’t bother,” noted Dr. Davidson, and he’s concerned that infrastructure challenges will also hamper the buy-and-bill strategy for inclisiran.

He also expressed skepticism that the prior-authorization barrier will disappear. “Payers don’t want to open a large population to a very expensive drug without some gatekeeping,” he said, while acknowledging that in late January 2022 he did not yet have personal experience administering inclisiran or navigating its insurance reimbursement.
 

Boosting patient compliance

Dr. Davidson agreed that the prospect for enhanced patient compliance with inclisiran was intriguing and had already drawn the interest of some of his patients.

“There is a lot of appeal” to a treatment that’s only given once every 6 months, he said. “Compliance is a major issue, and this is less work for patients.”

“The biggest possible attraction of inclisiran is that it is given twice a year, but whether this plays out as anticipated in the real world need to be seen,” cautioned Vijay Nambi, MD, a cardiologist at the Michael E. DeBakey VA Hospital, Houston, and at Baylor College of Medicine who has written about inclisiran. He noted that while two doses a year is “on paper very attractive,” this scheme opens the door to missed or delayed appointments because of vacations, other patient travel, or events like a pandemic.

“The biggest pro for inclisiran is the dosing schedule,” said Chandni Bardolia, PharmD, a drug information specialist at Tabula Rasa Healthcare, Moorestown, N.J., who has analyzed and written about inclisiran and other lipid-lowering medications. “Twice yearly dosing following initiation will be a huge benefit to improve adherence and reduce the number of injections.”

However, inclisiran’s attractive dosing schedule as well as its safety and potent efficacy do not tell the whole story, she highlighted in an interview.

Inclisiran’s clinical evidence still cooking

“I see inclisiran as a last-line drug, mainly because the current alternatives have more safety and efficacy data,” Dr. Bardolia said.

Inclisiran’s “cost and the fact that there are other agents with clinical outcome data already available [alirocumab and evolocumab] means inclisiran is not a first-line agent after statins,” agreed Dr. Nambi.

The FDA based its inclisiran approval entirely on the drug’s demonstrated safety and LDL-lowering efficacy. The cardiovascular outcomes trial for inclisiran, ORION-4, with about 15,000 enrolled patients, started in 2018 and remains in progress with full results expected in 2026.

The lack of clinical outcomes data for inclisiran is a major limitation, said Neil J. Stone, MD, a cardiologist and professor at Northwestern University, Chicago, and vice chair of the panel that wrote the most recent cholesterol guideline for the American College of Cardiology and American Heart Association.

“My greatest concern is the lack of outcome trial data. That’s very important,” Dr. Stone said in an interview.

But others minimize this limitation given the overwhelming evidence that links lower levels of LDL-cholesterol to reduced clinical events.

Most clinicians “support lower LDL as a surrogate” for reduced clinical events, “just like blood pressure and hemoglobin A1c,” noted Dr. Davidson, although he conceded that a “substantial minority wants to wait to see inclisiran’s outcome benefits.”
 

It’s all about price

While opinions are mixed on the need for clinical outcomes data, experts are more uniform in seeing drug prices that run to several thousands per year as the main uptake issue.

“We need to look at the cost-efficacy with inclisiran, and we need benefit data to determine this,” said Dr. Stone.

“Outcomes data are central to characterizing value. I imagine that costs will impact adoption and dissemination” of inclisiran, commented Paul L. Hess, MD, a cardiologist at the Rocky Mountain Regional VA Medical Center, Denver.

Patient interest in less frequent dosing will be important for driving use, but “ultimately cost will be the most important driving factor,” for inclisiran uptake, commented Robert H. Eckel, MD, an endocrinologist affiliated with the University of Colorado School of Medicine, Aurora.

Dr. Davidson has ties to New Amsterdam Pharma and Amgen, which markets evolocumab (Repatha). Dr. Ballantyne is a consultant to numerous companies, including Amgen and Regeneron, which market alirocumab (Praluent). Dr. Nambi has been a site investigator for studies sponsored by Amgen, and by Merck, which markets the LDL-cholesterol drug ezetimibe (Zetia) and is developing an oral PCSK9 inhibitor (he said that the views he expressed are his own and don’t represent that of the department of Veterans Affairs or Baylor.) Dr. Bardolia had no disclosures beyond her employment at Tabula Rasa Healthcare. Dr. Stone, Dr. Hess, and Dr. Eckel had no relevant disclosures.


 

As inclisiran, a first-in-class LDL-cholesterol lowering drug, enters the U.S. market following Food and Drug Administration approval in December 2021, several issues muddy how popular inclisiran will be in actual practice. That’s despite stellar phase 3 trial evidence for safety, tolerability, and a potent lipid-lowering effect.

The active ingredient of inclisiran (Leqvio) is a small interfering RNA (siRNA) molecule that shuts down production of the PCSK9 (proprotein convertase subtilisin/kexin type 9) protein, an enzyme that’s made and functions primarily in the liver and degrades cellular receptors for LDL cholesterol. Inhibiting PCSK9 production means LDL-cholesterol receptors accumulate and boost the ability of liver cells to pull more LDL cholesterol out of blood.

PCSK9 inhibition is the most potent LDL-cholesterol lowering method now available, and it works well in patients who have maxed out LDL reduction by diet and statin treatment. The siRNA of inclisiran is tweaked to target the molecule to the surface of liver cells following subcutaneous injection. Other modifications of the siRNA give it stability that allows twice-a-year dosing, although patients receive a third injection during their first year to hasten a maximum treatment effect.

Inclisiran’s FDA approval relied on results from three pivotal trials that together enrolled 3,660 patients with either atherosclerotic cardiovascular disease (ASCVD), ASCVD risk equivalents, or heterozygous familial hypercholesterolemia (HeFH), and LDL-cholesterol levels of at least 70 mg/dL in those with established ASCVD, or at least 100 mg/dL in other patients. (HeFH and ASCVD are the drug’s approved indications.) Pooled data from the three trials showed that inclisiran was safe and well tolerated during 18 months and produced an average LDL-cholesterol reduction after 510 days (1.4 years) of about 51% compared to baseline after correction for placebo effects (J Am Coll Cardiol. 2021 Mar 9;77 [9]:1182-93).

These data showed inclisiran was about as safe and effective for reducing LDL-cholesterol as agents from another class of PCSK9 inhibitors that rely on injected antibodies to inactivate PCSK9. Two agents from this class, alirocumab (Praluent) and evolocumab (Repatha), both came on the U.S. market in 2015. Although their performance in routine practice during the ensuing 6-plus years has been as safe and effective as what they showed in their respective registration trials, they have faced a rocky uptake road that’s been primarily hindered by the hefty price tag that both drugs carry.
 

Prior-authorization blues

When they first came out, evolocumab and alirocumab were burdened by annual drug costs of roughly $14,000, a fact that led to widespread prior-authorization and copay barriers set up by U.S. insurers. Although these barriers gradually lessened over time, in part aided by a substantial price cut for both drugs that led to annual drug costs more in the range of $6,000/year, they remain relatively pricey and are still not easy to start in patients because of prior-authorization requirements, said clinicians.

Recent penetration of the older PCSK9 inhibitors into eligible U.S. patients “is only about 1%-2%, based on the latest data,” said Michael H. Davidson, MD, a lipid specialist and director of Preventive Cardiology at the University of Chicago.

“We have these great, effective drugs, but they haven’t really made an impact over the past 5 years,” because of very limited uptake, a situation Dr. Davidson called “very disappointing,” during an interview.

Given this recent history, inclisiran, another expensive PCSK9 inhibitor, may face similar coverage pushback as it hits the U.S. market with a retail price, announced by its manufacturer Novartis, of $3,250/dose. This means that patients who start the drug and receive their initial dose, a second dose after 3 months, and then additional doses every 6 months, rack up a drug cost of close to $10,000 the first year on the drug and $6,500 each subsequent year.

This treatment schedule highlights the major logistical difference that distinguishes inclisiran from the antibody-based PCSK9 inhibitors, which are given by repeated subcutaneous injection every 2 or 4 weeks, usually with patients self-injecting the drugs at home. The less-frequent dosing schedule for inclisiran prompted the drug’s developers to schedule injections by a clinician in an office setting in the pivotal trials, which led to labeling for inclisiran that specifies administration only by a health care professional.
 

The ‘buy-and-bill’ coverage model

This difference in drug administration between inclisiran and the antibody-based PCSK9 inhibitors set up Novartis to promote insurance reimbursement for inclisiran using a “buy-and-bill” paradigm that was first developed for oncology drugs and which may provide a loophole around the prior-authorization roadblocks that hindered early uptake of the antibody-based PCSK9 inhibitors.

It’s also an approach that has made U.S. clinicians unsure how it will play out in practice. Infrequent inclisiran dosing may also boost patient compliance.

“Adherence is the greatest challenge in preventive cardiology, and thus inclisiran has the potential to be a game changer,” commented Christie M. Ballantyne, MD, professor and chief of cardiology at Baylor College of Medicine, Houston.

“Will it be easier for physicians to write a prescription and for patients to get the medication without a demanding and frustrating prior-authorization process?” he wondered during an interview. “I’m waiting to see how this unfolds, especially in systems where pharmacy is not fully integrated with the outpatient setting. In some ways, this is as big of an experiment as was development of the drug,” Dr. Ballantyne said.

Although the prior-authorization hoops for evolocumab and alirocumab have become easier to jump through, “most physicians don’t have the resources to handle it and don’t bother,” noted Dr. Davidson, and he’s concerned that infrastructure challenges will also hamper the buy-and-bill strategy for inclisiran.

He also expressed skepticism that the prior-authorization barrier will disappear. “Payers don’t want to open a large population to a very expensive drug without some gatekeeping,” he said, while acknowledging that in late January 2022 he did not yet have personal experience administering inclisiran or navigating its insurance reimbursement.
 

Boosting patient compliance

Dr. Davidson agreed that the prospect for enhanced patient compliance with inclisiran was intriguing and had already drawn the interest of some of his patients.

“There is a lot of appeal” to a treatment that’s only given once every 6 months, he said. “Compliance is a major issue, and this is less work for patients.”

“The biggest possible attraction of inclisiran is that it is given twice a year, but whether this plays out as anticipated in the real world need to be seen,” cautioned Vijay Nambi, MD, a cardiologist at the Michael E. DeBakey VA Hospital, Houston, and at Baylor College of Medicine who has written about inclisiran. He noted that while two doses a year is “on paper very attractive,” this scheme opens the door to missed or delayed appointments because of vacations, other patient travel, or events like a pandemic.

“The biggest pro for inclisiran is the dosing schedule,” said Chandni Bardolia, PharmD, a drug information specialist at Tabula Rasa Healthcare, Moorestown, N.J., who has analyzed and written about inclisiran and other lipid-lowering medications. “Twice yearly dosing following initiation will be a huge benefit to improve adherence and reduce the number of injections.”

However, inclisiran’s attractive dosing schedule as well as its safety and potent efficacy do not tell the whole story, she highlighted in an interview.

Inclisiran’s clinical evidence still cooking

“I see inclisiran as a last-line drug, mainly because the current alternatives have more safety and efficacy data,” Dr. Bardolia said.

Inclisiran’s “cost and the fact that there are other agents with clinical outcome data already available [alirocumab and evolocumab] means inclisiran is not a first-line agent after statins,” agreed Dr. Nambi.

The FDA based its inclisiran approval entirely on the drug’s demonstrated safety and LDL-lowering efficacy. The cardiovascular outcomes trial for inclisiran, ORION-4, with about 15,000 enrolled patients, started in 2018 and remains in progress with full results expected in 2026.

The lack of clinical outcomes data for inclisiran is a major limitation, said Neil J. Stone, MD, a cardiologist and professor at Northwestern University, Chicago, and vice chair of the panel that wrote the most recent cholesterol guideline for the American College of Cardiology and American Heart Association.

“My greatest concern is the lack of outcome trial data. That’s very important,” Dr. Stone said in an interview.

But others minimize this limitation given the overwhelming evidence that links lower levels of LDL-cholesterol to reduced clinical events.

Most clinicians “support lower LDL as a surrogate” for reduced clinical events, “just like blood pressure and hemoglobin A1c,” noted Dr. Davidson, although he conceded that a “substantial minority wants to wait to see inclisiran’s outcome benefits.”
 

It’s all about price

While opinions are mixed on the need for clinical outcomes data, experts are more uniform in seeing drug prices that run to several thousands per year as the main uptake issue.

“We need to look at the cost-efficacy with inclisiran, and we need benefit data to determine this,” said Dr. Stone.

“Outcomes data are central to characterizing value. I imagine that costs will impact adoption and dissemination” of inclisiran, commented Paul L. Hess, MD, a cardiologist at the Rocky Mountain Regional VA Medical Center, Denver.

Patient interest in less frequent dosing will be important for driving use, but “ultimately cost will be the most important driving factor,” for inclisiran uptake, commented Robert H. Eckel, MD, an endocrinologist affiliated with the University of Colorado School of Medicine, Aurora.

Dr. Davidson has ties to New Amsterdam Pharma and Amgen, which markets evolocumab (Repatha). Dr. Ballantyne is a consultant to numerous companies, including Amgen and Regeneron, which market alirocumab (Praluent). Dr. Nambi has been a site investigator for studies sponsored by Amgen, and by Merck, which markets the LDL-cholesterol drug ezetimibe (Zetia) and is developing an oral PCSK9 inhibitor (he said that the views he expressed are his own and don’t represent that of the department of Veterans Affairs or Baylor.) Dr. Bardolia had no disclosures beyond her employment at Tabula Rasa Healthcare. Dr. Stone, Dr. Hess, and Dr. Eckel had no relevant disclosures.


 

As inclisiran, a first-in-class LDL-cholesterol lowering drug, enters the U.S. market following Food and Drug Administration approval in December 2021, several issues muddy how popular inclisiran will be in actual practice. That’s despite stellar phase 3 trial evidence for safety, tolerability, and a potent lipid-lowering effect.

The active ingredient of inclisiran (Leqvio) is a small interfering RNA (siRNA) molecule that shuts down production of the PCSK9 (proprotein convertase subtilisin/kexin type 9) protein, an enzyme that’s made and functions primarily in the liver and degrades cellular receptors for LDL cholesterol. Inhibiting PCSK9 production means LDL-cholesterol receptors accumulate and boost the ability of liver cells to pull more LDL cholesterol out of blood.

PCSK9 inhibition is the most potent LDL-cholesterol lowering method now available, and it works well in patients who have maxed out LDL reduction by diet and statin treatment. The siRNA of inclisiran is tweaked to target the molecule to the surface of liver cells following subcutaneous injection. Other modifications of the siRNA give it stability that allows twice-a-year dosing, although patients receive a third injection during their first year to hasten a maximum treatment effect.

Inclisiran’s FDA approval relied on results from three pivotal trials that together enrolled 3,660 patients with either atherosclerotic cardiovascular disease (ASCVD), ASCVD risk equivalents, or heterozygous familial hypercholesterolemia (HeFH), and LDL-cholesterol levels of at least 70 mg/dL in those with established ASCVD, or at least 100 mg/dL in other patients. (HeFH and ASCVD are the drug’s approved indications.) Pooled data from the three trials showed that inclisiran was safe and well tolerated during 18 months and produced an average LDL-cholesterol reduction after 510 days (1.4 years) of about 51% compared to baseline after correction for placebo effects (J Am Coll Cardiol. 2021 Mar 9;77 [9]:1182-93).

These data showed inclisiran was about as safe and effective for reducing LDL-cholesterol as agents from another class of PCSK9 inhibitors that rely on injected antibodies to inactivate PCSK9. Two agents from this class, alirocumab (Praluent) and evolocumab (Repatha), both came on the U.S. market in 2015. Although their performance in routine practice during the ensuing 6-plus years has been as safe and effective as what they showed in their respective registration trials, they have faced a rocky uptake road that’s been primarily hindered by the hefty price tag that both drugs carry.
 

Prior-authorization blues

When they first came out, evolocumab and alirocumab were burdened by annual drug costs of roughly $14,000, a fact that led to widespread prior-authorization and copay barriers set up by U.S. insurers. Although these barriers gradually lessened over time, in part aided by a substantial price cut for both drugs that led to annual drug costs more in the range of $6,000/year, they remain relatively pricey and are still not easy to start in patients because of prior-authorization requirements, said clinicians.

Recent penetration of the older PCSK9 inhibitors into eligible U.S. patients “is only about 1%-2%, based on the latest data,” said Michael H. Davidson, MD, a lipid specialist and director of Preventive Cardiology at the University of Chicago.

“We have these great, effective drugs, but they haven’t really made an impact over the past 5 years,” because of very limited uptake, a situation Dr. Davidson called “very disappointing,” during an interview.

Given this recent history, inclisiran, another expensive PCSK9 inhibitor, may face similar coverage pushback as it hits the U.S. market with a retail price, announced by its manufacturer Novartis, of $3,250/dose. This means that patients who start the drug and receive their initial dose, a second dose after 3 months, and then additional doses every 6 months, rack up a drug cost of close to $10,000 the first year on the drug and $6,500 each subsequent year.

This treatment schedule highlights the major logistical difference that distinguishes inclisiran from the antibody-based PCSK9 inhibitors, which are given by repeated subcutaneous injection every 2 or 4 weeks, usually with patients self-injecting the drugs at home. The less-frequent dosing schedule for inclisiran prompted the drug’s developers to schedule injections by a clinician in an office setting in the pivotal trials, which led to labeling for inclisiran that specifies administration only by a health care professional.
 

The ‘buy-and-bill’ coverage model

This difference in drug administration between inclisiran and the antibody-based PCSK9 inhibitors set up Novartis to promote insurance reimbursement for inclisiran using a “buy-and-bill” paradigm that was first developed for oncology drugs and which may provide a loophole around the prior-authorization roadblocks that hindered early uptake of the antibody-based PCSK9 inhibitors.

It’s also an approach that has made U.S. clinicians unsure how it will play out in practice. Infrequent inclisiran dosing may also boost patient compliance.

“Adherence is the greatest challenge in preventive cardiology, and thus inclisiran has the potential to be a game changer,” commented Christie M. Ballantyne, MD, professor and chief of cardiology at Baylor College of Medicine, Houston.

“Will it be easier for physicians to write a prescription and for patients to get the medication without a demanding and frustrating prior-authorization process?” he wondered during an interview. “I’m waiting to see how this unfolds, especially in systems where pharmacy is not fully integrated with the outpatient setting. In some ways, this is as big of an experiment as was development of the drug,” Dr. Ballantyne said.

Although the prior-authorization hoops for evolocumab and alirocumab have become easier to jump through, “most physicians don’t have the resources to handle it and don’t bother,” noted Dr. Davidson, and he’s concerned that infrastructure challenges will also hamper the buy-and-bill strategy for inclisiran.

He also expressed skepticism that the prior-authorization barrier will disappear. “Payers don’t want to open a large population to a very expensive drug without some gatekeeping,” he said, while acknowledging that in late January 2022 he did not yet have personal experience administering inclisiran or navigating its insurance reimbursement.
 

Boosting patient compliance

Dr. Davidson agreed that the prospect for enhanced patient compliance with inclisiran was intriguing and had already drawn the interest of some of his patients.

“There is a lot of appeal” to a treatment that’s only given once every 6 months, he said. “Compliance is a major issue, and this is less work for patients.”

“The biggest possible attraction of inclisiran is that it is given twice a year, but whether this plays out as anticipated in the real world need to be seen,” cautioned Vijay Nambi, MD, a cardiologist at the Michael E. DeBakey VA Hospital, Houston, and at Baylor College of Medicine who has written about inclisiran. He noted that while two doses a year is “on paper very attractive,” this scheme opens the door to missed or delayed appointments because of vacations, other patient travel, or events like a pandemic.

“The biggest pro for inclisiran is the dosing schedule,” said Chandni Bardolia, PharmD, a drug information specialist at Tabula Rasa Healthcare, Moorestown, N.J., who has analyzed and written about inclisiran and other lipid-lowering medications. “Twice yearly dosing following initiation will be a huge benefit to improve adherence and reduce the number of injections.”

However, inclisiran’s attractive dosing schedule as well as its safety and potent efficacy do not tell the whole story, she highlighted in an interview.

Inclisiran’s clinical evidence still cooking

“I see inclisiran as a last-line drug, mainly because the current alternatives have more safety and efficacy data,” Dr. Bardolia said.

Inclisiran’s “cost and the fact that there are other agents with clinical outcome data already available [alirocumab and evolocumab] means inclisiran is not a first-line agent after statins,” agreed Dr. Nambi.

The FDA based its inclisiran approval entirely on the drug’s demonstrated safety and LDL-lowering efficacy. The cardiovascular outcomes trial for inclisiran, ORION-4, with about 15,000 enrolled patients, started in 2018 and remains in progress with full results expected in 2026.

The lack of clinical outcomes data for inclisiran is a major limitation, said Neil J. Stone, MD, a cardiologist and professor at Northwestern University, Chicago, and vice chair of the panel that wrote the most recent cholesterol guideline for the American College of Cardiology and American Heart Association.

“My greatest concern is the lack of outcome trial data. That’s very important,” Dr. Stone said in an interview.

But others minimize this limitation given the overwhelming evidence that links lower levels of LDL-cholesterol to reduced clinical events.

Most clinicians “support lower LDL as a surrogate” for reduced clinical events, “just like blood pressure and hemoglobin A1c,” noted Dr. Davidson, although he conceded that a “substantial minority wants to wait to see inclisiran’s outcome benefits.”
 

It’s all about price

While opinions are mixed on the need for clinical outcomes data, experts are more uniform in seeing drug prices that run to several thousands per year as the main uptake issue.

“We need to look at the cost-efficacy with inclisiran, and we need benefit data to determine this,” said Dr. Stone.

“Outcomes data are central to characterizing value. I imagine that costs will impact adoption and dissemination” of inclisiran, commented Paul L. Hess, MD, a cardiologist at the Rocky Mountain Regional VA Medical Center, Denver.

Patient interest in less frequent dosing will be important for driving use, but “ultimately cost will be the most important driving factor,” for inclisiran uptake, commented Robert H. Eckel, MD, an endocrinologist affiliated with the University of Colorado School of Medicine, Aurora.

Dr. Davidson has ties to New Amsterdam Pharma and Amgen, which markets evolocumab (Repatha). Dr. Ballantyne is a consultant to numerous companies, including Amgen and Regeneron, which market alirocumab (Praluent). Dr. Nambi has been a site investigator for studies sponsored by Amgen, and by Merck, which markets the LDL-cholesterol drug ezetimibe (Zetia) and is developing an oral PCSK9 inhibitor (he said that the views he expressed are his own and don’t represent that of the department of Veterans Affairs or Baylor.) Dr. Bardolia had no disclosures beyond her employment at Tabula Rasa Healthcare. Dr. Stone, Dr. Hess, and Dr. Eckel had no relevant disclosures.


 

The widely held notion that consuming small to moderate amounts of alcohol is good for cardiovascular health is not supported by the data, the World Heart Federation says in a new policy brief.

In fact, the evidence is clear that any level of drinking can contribute to loss of a healthy life, the organization says.

“Over the past several decades, the prevalence of cardiovascular disease has nearly doubled, and alcohol has played a major role in the incidence of much of it,” the WHF said in the brief.

“The portrayal of alcohol as necessary for a vibrant social life has diverted attention from the harms of alcohol use, as have the frequent and widely publicized claims that moderate drinking, such as a glass of red wine a day, can offer protection against cardiovascular disease,” Monika Arora, PhD, member of the WHF advocacy committee and coauthor of the brief, said in a news release.

“These claims are at best misinformed and at worst an attempt by the alcohol industry to mislead the public about the danger of their product,” Dr. Arora added.

The WHF conclusions follow a report in the Lancet based on the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), which found that there is no safe level of alcohol consumption.

In 2019, nearly 2.4 million deaths were attributed to alcohol, accounting for 4.3% of all deaths globally and 12.6% of deaths in men 15 to 49 years of age.

Even small amounts of alcohol have been shown to raise the risk for cardiovascular disease, including coronary disease, stroke, heart failure, hypertensive heart disease, cardiomyopathy, atrial fibrillation, and aneurysm, the WHF notes.

Studies that claim otherwise are largely based on purely observational research, which fails to account for relevant cofactors, the organization writes.

Based on their summary of the evidence to date, there is no reliable correlation between moderate alcohol consumption and a lower risk for cardiovascular disease.

Alcohol use is also a “major avoidable risk factor” for cancer, digestive diseases, intentional and unintentional injuries, and several infectious diseases, the WHF says.

Alcohol use also has significant economic and social costs, which include costs to individuals and health systems, productivity losses, as well as the increased risk for violence, homelessness, and criminal activity.

The WHF policy brief calls for “urgent and decisive action” to tackle the unprecedented rise in alcohol-related death and disability worldwide.

Recommended actions include boosting restrictions on alcohol availability; advancing and enforcing drinking and driving countermeasures; increasing access to screening, brief interventions, and treatment for alcohol use disorder; enforcing bans on alcohol advertising; establishing a uniform minimum legal drinking age; and mandating health warnings on alcohol products.

A version of this article first appeared on Medscape.com.

The widely held notion that consuming small to moderate amounts of alcohol is good for cardiovascular health is not supported by the data, the World Heart Federation says in a new policy brief.

In fact, the evidence is clear that any level of drinking can contribute to loss of a healthy life, the organization says.

“Over the past several decades, the prevalence of cardiovascular disease has nearly doubled, and alcohol has played a major role in the incidence of much of it,” the WHF said in the brief.

“The portrayal of alcohol as necessary for a vibrant social life has diverted attention from the harms of alcohol use, as have the frequent and widely publicized claims that moderate drinking, such as a glass of red wine a day, can offer protection against cardiovascular disease,” Monika Arora, PhD, member of the WHF advocacy committee and coauthor of the brief, said in a news release.

“These claims are at best misinformed and at worst an attempt by the alcohol industry to mislead the public about the danger of their product,” Dr. Arora added.

The WHF conclusions follow a report in the Lancet based on the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), which found that there is no safe level of alcohol consumption.

In 2019, nearly 2.4 million deaths were attributed to alcohol, accounting for 4.3% of all deaths globally and 12.6% of deaths in men 15 to 49 years of age.

Even small amounts of alcohol have been shown to raise the risk for cardiovascular disease, including coronary disease, stroke, heart failure, hypertensive heart disease, cardiomyopathy, atrial fibrillation, and aneurysm, the WHF notes.

Studies that claim otherwise are largely based on purely observational research, which fails to account for relevant cofactors, the organization writes.

Based on their summary of the evidence to date, there is no reliable correlation between moderate alcohol consumption and a lower risk for cardiovascular disease.

Alcohol use is also a “major avoidable risk factor” for cancer, digestive diseases, intentional and unintentional injuries, and several infectious diseases, the WHF says.

Alcohol use also has significant economic and social costs, which include costs to individuals and health systems, productivity losses, as well as the increased risk for violence, homelessness, and criminal activity.

The WHF policy brief calls for “urgent and decisive action” to tackle the unprecedented rise in alcohol-related death and disability worldwide.

Recommended actions include boosting restrictions on alcohol availability; advancing and enforcing drinking and driving countermeasures; increasing access to screening, brief interventions, and treatment for alcohol use disorder; enforcing bans on alcohol advertising; establishing a uniform minimum legal drinking age; and mandating health warnings on alcohol products.

A version of this article first appeared on Medscape.com.

The widely held notion that consuming small to moderate amounts of alcohol is good for cardiovascular health is not supported by the data, the World Heart Federation says in a new policy brief.

In fact, the evidence is clear that any level of drinking can contribute to loss of a healthy life, the organization says.

“Over the past several decades, the prevalence of cardiovascular disease has nearly doubled, and alcohol has played a major role in the incidence of much of it,” the WHF said in the brief.

“The portrayal of alcohol as necessary for a vibrant social life has diverted attention from the harms of alcohol use, as have the frequent and widely publicized claims that moderate drinking, such as a glass of red wine a day, can offer protection against cardiovascular disease,” Monika Arora, PhD, member of the WHF advocacy committee and coauthor of the brief, said in a news release.

“These claims are at best misinformed and at worst an attempt by the alcohol industry to mislead the public about the danger of their product,” Dr. Arora added.

The WHF conclusions follow a report in the Lancet based on the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), which found that there is no safe level of alcohol consumption.

In 2019, nearly 2.4 million deaths were attributed to alcohol, accounting for 4.3% of all deaths globally and 12.6% of deaths in men 15 to 49 years of age.

Even small amounts of alcohol have been shown to raise the risk for cardiovascular disease, including coronary disease, stroke, heart failure, hypertensive heart disease, cardiomyopathy, atrial fibrillation, and aneurysm, the WHF notes.

Studies that claim otherwise are largely based on purely observational research, which fails to account for relevant cofactors, the organization writes.

Based on their summary of the evidence to date, there is no reliable correlation between moderate alcohol consumption and a lower risk for cardiovascular disease.

Alcohol use is also a “major avoidable risk factor” for cancer, digestive diseases, intentional and unintentional injuries, and several infectious diseases, the WHF says.

Alcohol use also has significant economic and social costs, which include costs to individuals and health systems, productivity losses, as well as the increased risk for violence, homelessness, and criminal activity.

The WHF policy brief calls for “urgent and decisive action” to tackle the unprecedented rise in alcohol-related death and disability worldwide.

Recommended actions include boosting restrictions on alcohol availability; advancing and enforcing drinking and driving countermeasures; increasing access to screening, brief interventions, and treatment for alcohol use disorder; enforcing bans on alcohol advertising; establishing a uniform minimum legal drinking age; and mandating health warnings on alcohol products.

A version of this article first appeared on Medscape.com.

Therapeutic inertia regarding intensification of blood pressure treatment has been shown to be more of an issue in Black patients, but this was not the case in the SPRINT trial, which involved a strict standardized approach to blood pressure management, a new analysis shows.

Ingram Publishing/ThinkStock

“Overall, we found that therapeutic inertia was similar in different races in the SPRINT trial. We did not see disparities that have been reported in previous observational studies,” lead author, Alexander Zheutlin, MD, University of Utah School of Medicine, Salt Lake City, told this news organization.

“These results show that a well-resourced approach in which a standardized approach to blood pressure measurement and treatment intensification is followed can overcome the racial disparity that is seen in therapeutic inertia and the treatment of blood pressure,” he added.

The study was published online in JAMA Network Open on Jan. 10.

The authors explain that hypertension remains a leading modifiable cause of racial disparities in cardiovascular disease. Despite similar treatment rates and increased availability of safe, effective, and affordable antihypertensive medications, blood pressure control rates among Black and Hispanic adults remain significantly lower than among White adults in the United States, and one of the factors contributing to this is thought to be therapeutic inertia – the phenomenon of clinicians not initiating or up-titrating clinically indicated therapy in the setting of unmet treatment goals.

The current analysis of the SPRINT trial was conducted to investigate whether racial and ethnic differences in therapeutic inertia in hypertension were present when blood pressure care was standardized and protocolized.

The landmark SPRINT trial compared intensive (<120 mm Hg) with standard (<140 mm Hg) systolic blood pressure treatment goals in adults 50 years and older at high risk for cardiovascular disease. The present analysis was restricted to participant visits with measured blood pressure above the target goal and included 4,141 patients in the standard group and 4,415 patients in the intensive group.

Results showed that the overall prevalence of therapeutic inertia – defined as no antihypertensive medication intensification at each study visit where the blood pressure was above target goal – was either similar or lower for Black and Hispanic participants than for White participants. This pattern was observed whether participants were randomized to the standard or intensive treatment group.

“These findings support the idea that a standardized approach to blood pressure management, as implemented in SPRINT, may help ensure equitable care is provided to all patients and could reduce the contribution of therapeutic inertia to disparities in uncontrolled blood pressure,” the authors say.

They point out that therapeutic inertia has been identified as a key clinician-level barrier to blood pressure control and is estimated to be present in more than 80% of clinic visits in community practice, whereas in the current analysis of the SPRINT trial, therapeutic inertia was present in 50% to 60% of participant visits with uncontrolled blood pressure.

“In SPRINT, blood pressure had to be measured at defined intervals with a specific method, and there were clear instructions on intensifying treatment if blood pressure was above a certain goal,” Dr. Zheutlin noted. “Our results show that within such strict confines, therapeutic inertia does not seem to be different between different racial groups. This suggests that we could make better gains in blood pressure control and more equitable treatment if we adopted a standardized approach to hypertension management.”

He added: “Many guidelines have been published on when to start treatment and the targets for blood pressure, but there is a lot of variation in how we turn these guidelines into protocols. We need to bring in more consistent protocols on blood pressure measurement and intensification and ensure they are followed. In practice, if the BP is 5 or 10 mm Hg above target, a clinician may defer a decision to intensify treatment and intensification never gets done. But if there was a strict protocol to follow, there would be less chance of this happening.”
 

Therapeutic inertia still high

In an accompanying commentary, Matthew Rivara, MD, Nisha Bansal, MD, and Bessie Young, MD, University of Washington, Seattle, say the current SPRINT analysis has broad implications for reducing racial and ethnic disparities in achievement of evidence-based treatment targets in the general population.

“In hypertension management, standardized protocols for medication adjustments may limit clinician practice heterogeneity to ultimately reduce differences in blood pressure control among racial and ethnic minority populations,” they write. But they add that such protocols must be implemented thoughtfully to incorporate individualized clinical assessment and clinician-patient shared decision-making.

Dr. Rivara et al. point out that the rates of therapeutic inertia in SPRINT, while lower than community-based estimates, were still very high. They suggest reasons for this could include clinician concerns about medication efficacy, adverse effects, and patient mistrust of medical professionals. Outside the clinical trial environment, additional considerations may include prescription drug and laboratory test costs, pharmacy access, and competing demands during busy clinic visits.

To address these challenges, they say that clinicians need education on current clinical practice guidelines, managing complications of intensified antihypertensive therapies, and shared decisionmaking, including culturally sensitive collaborative care. Similarly, care systems must support patients on how to address concerns about treatments.

Finally, further research is needed to better define the specific factors associated with therapeutic inertia to allow tailored interventions to overcome this inertia.

“In designing and performing such research, it is vital that investigators engage with racial and ethnic minority groups to better explore the intersection of race, ethnicity, therapeutic decision-making, trust, and shared decisionmaking,” they add.

The SPRINT trial was funded with federal funds from the National Institutes of Health. Dr. Zheutlin reported receiving grants from the NIH during the conduct of the study.

A version of this article first appeared on Medscape.com.

Therapeutic inertia regarding intensification of blood pressure treatment has been shown to be more of an issue in Black patients, but this was not the case in the SPRINT trial, which involved a strict standardized approach to blood pressure management, a new analysis shows.

Ingram Publishing/ThinkStock

“Overall, we found that therapeutic inertia was similar in different races in the SPRINT trial. We did not see disparities that have been reported in previous observational studies,” lead author, Alexander Zheutlin, MD, University of Utah School of Medicine, Salt Lake City, told this news organization.

“These results show that a well-resourced approach in which a standardized approach to blood pressure measurement and treatment intensification is followed can overcome the racial disparity that is seen in therapeutic inertia and the treatment of blood pressure,” he added.

The study was published online in JAMA Network Open on Jan. 10.

The authors explain that hypertension remains a leading modifiable cause of racial disparities in cardiovascular disease. Despite similar treatment rates and increased availability of safe, effective, and affordable antihypertensive medications, blood pressure control rates among Black and Hispanic adults remain significantly lower than among White adults in the United States, and one of the factors contributing to this is thought to be therapeutic inertia – the phenomenon of clinicians not initiating or up-titrating clinically indicated therapy in the setting of unmet treatment goals.

The current analysis of the SPRINT trial was conducted to investigate whether racial and ethnic differences in therapeutic inertia in hypertension were present when blood pressure care was standardized and protocolized.

The landmark SPRINT trial compared intensive (<120 mm Hg) with standard (<140 mm Hg) systolic blood pressure treatment goals in adults 50 years and older at high risk for cardiovascular disease. The present analysis was restricted to participant visits with measured blood pressure above the target goal and included 4,141 patients in the standard group and 4,415 patients in the intensive group.

Results showed that the overall prevalence of therapeutic inertia – defined as no antihypertensive medication intensification at each study visit where the blood pressure was above target goal – was either similar or lower for Black and Hispanic participants than for White participants. This pattern was observed whether participants were randomized to the standard or intensive treatment group.

“These findings support the idea that a standardized approach to blood pressure management, as implemented in SPRINT, may help ensure equitable care is provided to all patients and could reduce the contribution of therapeutic inertia to disparities in uncontrolled blood pressure,” the authors say.

They point out that therapeutic inertia has been identified as a key clinician-level barrier to blood pressure control and is estimated to be present in more than 80% of clinic visits in community practice, whereas in the current analysis of the SPRINT trial, therapeutic inertia was present in 50% to 60% of participant visits with uncontrolled blood pressure.

“In SPRINT, blood pressure had to be measured at defined intervals with a specific method, and there were clear instructions on intensifying treatment if blood pressure was above a certain goal,” Dr. Zheutlin noted. “Our results show that within such strict confines, therapeutic inertia does not seem to be different between different racial groups. This suggests that we could make better gains in blood pressure control and more equitable treatment if we adopted a standardized approach to hypertension management.”

He added: “Many guidelines have been published on when to start treatment and the targets for blood pressure, but there is a lot of variation in how we turn these guidelines into protocols. We need to bring in more consistent protocols on blood pressure measurement and intensification and ensure they are followed. In practice, if the BP is 5 or 10 mm Hg above target, a clinician may defer a decision to intensify treatment and intensification never gets done. But if there was a strict protocol to follow, there would be less chance of this happening.”
 

Therapeutic inertia still high

In an accompanying commentary, Matthew Rivara, MD, Nisha Bansal, MD, and Bessie Young, MD, University of Washington, Seattle, say the current SPRINT analysis has broad implications for reducing racial and ethnic disparities in achievement of evidence-based treatment targets in the general population.

“In hypertension management, standardized protocols for medication adjustments may limit clinician practice heterogeneity to ultimately reduce differences in blood pressure control among racial and ethnic minority populations,” they write. But they add that such protocols must be implemented thoughtfully to incorporate individualized clinical assessment and clinician-patient shared decision-making.

Dr. Rivara et al. point out that the rates of therapeutic inertia in SPRINT, while lower than community-based estimates, were still very high. They suggest reasons for this could include clinician concerns about medication efficacy, adverse effects, and patient mistrust of medical professionals. Outside the clinical trial environment, additional considerations may include prescription drug and laboratory test costs, pharmacy access, and competing demands during busy clinic visits.

To address these challenges, they say that clinicians need education on current clinical practice guidelines, managing complications of intensified antihypertensive therapies, and shared decisionmaking, including culturally sensitive collaborative care. Similarly, care systems must support patients on how to address concerns about treatments.

Finally, further research is needed to better define the specific factors associated with therapeutic inertia to allow tailored interventions to overcome this inertia.

“In designing and performing such research, it is vital that investigators engage with racial and ethnic minority groups to better explore the intersection of race, ethnicity, therapeutic decision-making, trust, and shared decisionmaking,” they add.

The SPRINT trial was funded with federal funds from the National Institutes of Health. Dr. Zheutlin reported receiving grants from the NIH during the conduct of the study.

A version of this article first appeared on Medscape.com.

Therapeutic inertia regarding intensification of blood pressure treatment has been shown to be more of an issue in Black patients, but this was not the case in the SPRINT trial, which involved a strict standardized approach to blood pressure management, a new analysis shows.

Ingram Publishing/ThinkStock

“Overall, we found that therapeutic inertia was similar in different races in the SPRINT trial. We did not see disparities that have been reported in previous observational studies,” lead author, Alexander Zheutlin, MD, University of Utah School of Medicine, Salt Lake City, told this news organization.

“These results show that a well-resourced approach in which a standardized approach to blood pressure measurement and treatment intensification is followed can overcome the racial disparity that is seen in therapeutic inertia and the treatment of blood pressure,” he added.

The study was published online in JAMA Network Open on Jan. 10.

The authors explain that hypertension remains a leading modifiable cause of racial disparities in cardiovascular disease. Despite similar treatment rates and increased availability of safe, effective, and affordable antihypertensive medications, blood pressure control rates among Black and Hispanic adults remain significantly lower than among White adults in the United States, and one of the factors contributing to this is thought to be therapeutic inertia – the phenomenon of clinicians not initiating or up-titrating clinically indicated therapy in the setting of unmet treatment goals.

The current analysis of the SPRINT trial was conducted to investigate whether racial and ethnic differences in therapeutic inertia in hypertension were present when blood pressure care was standardized and protocolized.

The landmark SPRINT trial compared intensive (<120 mm Hg) with standard (<140 mm Hg) systolic blood pressure treatment goals in adults 50 years and older at high risk for cardiovascular disease. The present analysis was restricted to participant visits with measured blood pressure above the target goal and included 4,141 patients in the standard group and 4,415 patients in the intensive group.

Results showed that the overall prevalence of therapeutic inertia – defined as no antihypertensive medication intensification at each study visit where the blood pressure was above target goal – was either similar or lower for Black and Hispanic participants than for White participants. This pattern was observed whether participants were randomized to the standard or intensive treatment group.

“These findings support the idea that a standardized approach to blood pressure management, as implemented in SPRINT, may help ensure equitable care is provided to all patients and could reduce the contribution of therapeutic inertia to disparities in uncontrolled blood pressure,” the authors say.

They point out that therapeutic inertia has been identified as a key clinician-level barrier to blood pressure control and is estimated to be present in more than 80% of clinic visits in community practice, whereas in the current analysis of the SPRINT trial, therapeutic inertia was present in 50% to 60% of participant visits with uncontrolled blood pressure.

“In SPRINT, blood pressure had to be measured at defined intervals with a specific method, and there were clear instructions on intensifying treatment if blood pressure was above a certain goal,” Dr. Zheutlin noted. “Our results show that within such strict confines, therapeutic inertia does not seem to be different between different racial groups. This suggests that we could make better gains in blood pressure control and more equitable treatment if we adopted a standardized approach to hypertension management.”

He added: “Many guidelines have been published on when to start treatment and the targets for blood pressure, but there is a lot of variation in how we turn these guidelines into protocols. We need to bring in more consistent protocols on blood pressure measurement and intensification and ensure they are followed. In practice, if the BP is 5 or 10 mm Hg above target, a clinician may defer a decision to intensify treatment and intensification never gets done. But if there was a strict protocol to follow, there would be less chance of this happening.”
 

Therapeutic inertia still high

In an accompanying commentary, Matthew Rivara, MD, Nisha Bansal, MD, and Bessie Young, MD, University of Washington, Seattle, say the current SPRINT analysis has broad implications for reducing racial and ethnic disparities in achievement of evidence-based treatment targets in the general population.

“In hypertension management, standardized protocols for medication adjustments may limit clinician practice heterogeneity to ultimately reduce differences in blood pressure control among racial and ethnic minority populations,” they write. But they add that such protocols must be implemented thoughtfully to incorporate individualized clinical assessment and clinician-patient shared decision-making.

Dr. Rivara et al. point out that the rates of therapeutic inertia in SPRINT, while lower than community-based estimates, were still very high. They suggest reasons for this could include clinician concerns about medication efficacy, adverse effects, and patient mistrust of medical professionals. Outside the clinical trial environment, additional considerations may include prescription drug and laboratory test costs, pharmacy access, and competing demands during busy clinic visits.

To address these challenges, they say that clinicians need education on current clinical practice guidelines, managing complications of intensified antihypertensive therapies, and shared decisionmaking, including culturally sensitive collaborative care. Similarly, care systems must support patients on how to address concerns about treatments.

Finally, further research is needed to better define the specific factors associated with therapeutic inertia to allow tailored interventions to overcome this inertia.

“In designing and performing such research, it is vital that investigators engage with racial and ethnic minority groups to better explore the intersection of race, ethnicity, therapeutic decision-making, trust, and shared decisionmaking,” they add.

The SPRINT trial was funded with federal funds from the National Institutes of Health. Dr. Zheutlin reported receiving grants from the NIH during the conduct of the study.

A version of this article first appeared on Medscape.com.

Myocardial inflammation is present in a small proportion of patients who have recovered from relatively mild cases of COVID-19 infection, a new study shows.

“Our findings suggest that even in patients who have had relatively mild cases of COVID-19, some will have inflammatory changes to the heart, and these changes can be present without any cardiac symptoms,” senior author, Paaladinesh Thavendiranathan, MD, University of Toronto, told this news organization.

Floaria Bicher/iStock/Getty Images Plus

A version of this article first appeared on Medscape.com.

Myocardial inflammation is present in a small proportion of patients who have recovered from relatively mild cases of COVID-19 infection, a new study shows.

“Our findings suggest that even in patients who have had relatively mild cases of COVID-19, some will have inflammatory changes to the heart, and these changes can be present without any cardiac symptoms,” senior author, Paaladinesh Thavendiranathan, MD, University of Toronto, told this news organization.

Floaria Bicher/iStock/Getty Images Plus

A version of this article first appeared on Medscape.com.

Myocardial inflammation is present in a small proportion of patients who have recovered from relatively mild cases of COVID-19 infection, a new study shows.

“Our findings suggest that even in patients who have had relatively mild cases of COVID-19, some will have inflammatory changes to the heart, and these changes can be present without any cardiac symptoms,” senior author, Paaladinesh Thavendiranathan, MD, University of Toronto, told this news organization.

Floaria Bicher/iStock/Getty Images Plus

A version of this article first appeared on Medscape.com.

Scientific achievements usually raise big new questions, and the remarkable surgery that took place on Jan. 7, when Maryland resident David Bennett was transplanted with a genetically modified heart from a pig, has been no different.

The 57-year-old with end-stage heart failure had been repeatedly turned down for a standard transplant and was judged a poor candidate for a ventricular assist device. Now his new heart is beating soundly and apparently accepted by his immune system as Mr. Bennett, his physicians at the University of Maryland where the procedure took place, and indeed the world set out on a journey with far more unknowns than knowns.

University of Maryland Medical Center

“I think even just a couple of years ago, people felt that xenotransplantation for the heart and other organs was still a long way off. And it seems like it’s started to move very quickly,” Larry A. Allen, MD, University of Colorado, Aurora, said in an interview.

Demand for donor hearts far outstrips supply, and despite advances in the development of ventricular assist pumps and artificial hearts, “there are still significant limitations to them in terms of clotting, stroke, and infection. We’ve seen the use of those devices plateau,” Dr. Allen said. “So, the concept of a nonhuman source of organs is exciting and very much in need, if people can get it to work.”

“I really credit the surgeons at the University of Maryland for courageous clinical work and a brilliant scientific innovation,” Clyde W. Yancy, MD, MSc, Northwestern University, Chicago, said in an interview. “But it’s always in the implementation that we have to hold our breath.” Heart xenotransplantation is an old idea that “has never before been successful,” he said. And standard heart transplantation has set a high bar, with a 1-year survival of about 90% and low 1-year risk for rejection. Whether the new procedure can meet that standard is unknown, as is its potential for complications, such as chronic rejection or cancers due to long-term immunosuppression. Those are “major questions requiring more time and careful follow-up.”

‘Still a nascent technology’

“This is an exciting and courageous step forward in heart transplantation, and kudos to the team at the University of Maryland,” said Mandeep R. Mehra, MD, Brigham and Woman’s Hospital, Boston. But “there are many challenges here.”

University of Maryland Medical Center

The procedure’s 10 gene modifications were reportedly aimed at preventing hyperacute rejection of the heart and its excessive growth after transplantation, and making the organ less immunogenic, Dr. Mehra said in an interview. But even if those goals are met, could the same changes potentially impede the heart’s adaptation to human physiology, such as during ambulation or stress?

That kind of adaptation may become important. For example, Dr. Mehra observed, normally a pig heart “provides flow in a four-footed configuration, and pig temperature is inherently higher than humans by several degrees, so it will be functioning in a relatively hypothermic environment.”

Transplantation remains the gold standard for patients with advanced heart failure despite modern medical and device therapy, Dr. Allen agreed. But “if we can raise pig hearts that provide the organ, and it can be implanted with a surgery that’s been done for 50 years, and rejection can be managed with gene editing and tailored immunosuppression, then it’s not hard to think about this very rapidly replacing a lot of what we do in the advanced heart failure and transplantation world.”

Certainly, it would be a major advance if the gene editing technique successfully improves the heart’s immunologic compatibility, Dr. Yancy noted. But do we have enough genomic knowledge to select gene deletions and insertions in the safest way for a successful outcome? “We have to appreciate that this is still a nascent technology, and we should be careful that there might be consequences that we haven’t anticipated.”

For example, he said, the xenotransplantation and gene-modifying techniques should be explored in a range of patients, including older and younger people, women and men, and people of different ethnicities and races.

“There may be some differences based on ancestry, based on gender, based on aging, that will influence the way in which these engineered donor hearts are experienced clinically,” Dr. Yancy said.

The xenotransplantation technique’s potential impact on health equity should also be considered, as it “almost assuredly will be a very expensive technology that will be utilized in a very select population,” he noted. “We need to have a really wide lens to think about all of the potential ramifications.”
 

‘This field needs to evolve’

Dr. Mehra also flagged the procedure’s potential cost should it become mainstream. Perhaps that would promote dialogue on how to primarily use it “after legitimately exhausting all available options, such as total artificial heart support.”

It might also teach the field to take greater advantage of the many donated hearts discarded as suboptimal. “The general usage rate for offered organs is around a third,” despite opportunities to expand use of those that are “less than perfect,” Dr. Mehra said. “I think that the field will grow with the community focusing on reduced discards of current available heart organs, and not necessarily grow because of the availability of ‘xeno-organs.’ ”

“This field needs to evolve because we’re actively transplanting patients today. But in my mind, the real future is to have such a sufficient understanding of the biology of left ventricular dysfunction that transplantation is a rare event,” Dr. Yancy proposed.

“I’m not certain that heart transplantation per se is the endgame. I think the avoidance of transplantation is the real endgame,” he said. “This may be controversial, but my vision of the future is not one where we have a supply of animals that we can use for transplantation. My vision of the future is that heart transplantation becomes obsolete.”

A version of this article first appeared on Medscape.com.

Scientific achievements usually raise big new questions, and the remarkable surgery that took place on Jan. 7, when Maryland resident David Bennett was transplanted with a genetically modified heart from a pig, has been no different.

The 57-year-old with end-stage heart failure had been repeatedly turned down for a standard transplant and was judged a poor candidate for a ventricular assist device. Now his new heart is beating soundly and apparently accepted by his immune system as Mr. Bennett, his physicians at the University of Maryland where the procedure took place, and indeed the world set out on a journey with far more unknowns than knowns.

University of Maryland Medical Center

“I think even just a couple of years ago, people felt that xenotransplantation for the heart and other organs was still a long way off. And it seems like it’s started to move very quickly,” Larry A. Allen, MD, University of Colorado, Aurora, said in an interview.

Demand for donor hearts far outstrips supply, and despite advances in the development of ventricular assist pumps and artificial hearts, “there are still significant limitations to them in terms of clotting, stroke, and infection. We’ve seen the use of those devices plateau,” Dr. Allen said. “So, the concept of a nonhuman source of organs is exciting and very much in need, if people can get it to work.”

“I really credit the surgeons at the University of Maryland for courageous clinical work and a brilliant scientific innovation,” Clyde W. Yancy, MD, MSc, Northwestern University, Chicago, said in an interview. “But it’s always in the implementation that we have to hold our breath.” Heart xenotransplantation is an old idea that “has never before been successful,” he said. And standard heart transplantation has set a high bar, with a 1-year survival of about 90% and low 1-year risk for rejection. Whether the new procedure can meet that standard is unknown, as is its potential for complications, such as chronic rejection or cancers due to long-term immunosuppression. Those are “major questions requiring more time and careful follow-up.”

‘Still a nascent technology’

“This is an exciting and courageous step forward in heart transplantation, and kudos to the team at the University of Maryland,” said Mandeep R. Mehra, MD, Brigham and Woman’s Hospital, Boston. But “there are many challenges here.”

University of Maryland Medical Center

The procedure’s 10 gene modifications were reportedly aimed at preventing hyperacute rejection of the heart and its excessive growth after transplantation, and making the organ less immunogenic, Dr. Mehra said in an interview. But even if those goals are met, could the same changes potentially impede the heart’s adaptation to human physiology, such as during ambulation or stress?

That kind of adaptation may become important. For example, Dr. Mehra observed, normally a pig heart “provides flow in a four-footed configuration, and pig temperature is inherently higher than humans by several degrees, so it will be functioning in a relatively hypothermic environment.”

Transplantation remains the gold standard for patients with advanced heart failure despite modern medical and device therapy, Dr. Allen agreed. But “if we can raise pig hearts that provide the organ, and it can be implanted with a surgery that’s been done for 50 years, and rejection can be managed with gene editing and tailored immunosuppression, then it’s not hard to think about this very rapidly replacing a lot of what we do in the advanced heart failure and transplantation world.”

Certainly, it would be a major advance if the gene editing technique successfully improves the heart’s immunologic compatibility, Dr. Yancy noted. But do we have enough genomic knowledge to select gene deletions and insertions in the safest way for a successful outcome? “We have to appreciate that this is still a nascent technology, and we should be careful that there might be consequences that we haven’t anticipated.”

For example, he said, the xenotransplantation and gene-modifying techniques should be explored in a range of patients, including older and younger people, women and men, and people of different ethnicities and races.

“There may be some differences based on ancestry, based on gender, based on aging, that will influence the way in which these engineered donor hearts are experienced clinically,” Dr. Yancy said.

The xenotransplantation technique’s potential impact on health equity should also be considered, as it “almost assuredly will be a very expensive technology that will be utilized in a very select population,” he noted. “We need to have a really wide lens to think about all of the potential ramifications.”
 

‘This field needs to evolve’

Dr. Mehra also flagged the procedure’s potential cost should it become mainstream. Perhaps that would promote dialogue on how to primarily use it “after legitimately exhausting all available options, such as total artificial heart support.”

It might also teach the field to take greater advantage of the many donated hearts discarded as suboptimal. “The general usage rate for offered organs is around a third,” despite opportunities to expand use of those that are “less than perfect,” Dr. Mehra said. “I think that the field will grow with the community focusing on reduced discards of current available heart organs, and not necessarily grow because of the availability of ‘xeno-organs.’ ”

“This field needs to evolve because we’re actively transplanting patients today. But in my mind, the real future is to have such a sufficient understanding of the biology of left ventricular dysfunction that transplantation is a rare event,” Dr. Yancy proposed.

“I’m not certain that heart transplantation per se is the endgame. I think the avoidance of transplantation is the real endgame,” he said. “This may be controversial, but my vision of the future is not one where we have a supply of animals that we can use for transplantation. My vision of the future is that heart transplantation becomes obsolete.”

A version of this article first appeared on Medscape.com.

Scientific achievements usually raise big new questions, and the remarkable surgery that took place on Jan. 7, when Maryland resident David Bennett was transplanted with a genetically modified heart from a pig, has been no different.

The 57-year-old with end-stage heart failure had been repeatedly turned down for a standard transplant and was judged a poor candidate for a ventricular assist device. Now his new heart is beating soundly and apparently accepted by his immune system as Mr. Bennett, his physicians at the University of Maryland where the procedure took place, and indeed the world set out on a journey with far more unknowns than knowns.

University of Maryland Medical Center

“I think even just a couple of years ago, people felt that xenotransplantation for the heart and other organs was still a long way off. And it seems like it’s started to move very quickly,” Larry A. Allen, MD, University of Colorado, Aurora, said in an interview.

Demand for donor hearts far outstrips supply, and despite advances in the development of ventricular assist pumps and artificial hearts, “there are still significant limitations to them in terms of clotting, stroke, and infection. We’ve seen the use of those devices plateau,” Dr. Allen said. “So, the concept of a nonhuman source of organs is exciting and very much in need, if people can get it to work.”

“I really credit the surgeons at the University of Maryland for courageous clinical work and a brilliant scientific innovation,” Clyde W. Yancy, MD, MSc, Northwestern University, Chicago, said in an interview. “But it’s always in the implementation that we have to hold our breath.” Heart xenotransplantation is an old idea that “has never before been successful,” he said. And standard heart transplantation has set a high bar, with a 1-year survival of about 90% and low 1-year risk for rejection. Whether the new procedure can meet that standard is unknown, as is its potential for complications, such as chronic rejection or cancers due to long-term immunosuppression. Those are “major questions requiring more time and careful follow-up.”

‘Still a nascent technology’

“This is an exciting and courageous step forward in heart transplantation, and kudos to the team at the University of Maryland,” said Mandeep R. Mehra, MD, Brigham and Woman’s Hospital, Boston. But “there are many challenges here.”

University of Maryland Medical Center

The procedure’s 10 gene modifications were reportedly aimed at preventing hyperacute rejection of the heart and its excessive growth after transplantation, and making the organ less immunogenic, Dr. Mehra said in an interview. But even if those goals are met, could the same changes potentially impede the heart’s adaptation to human physiology, such as during ambulation or stress?

That kind of adaptation may become important. For example, Dr. Mehra observed, normally a pig heart “provides flow in a four-footed configuration, and pig temperature is inherently higher than humans by several degrees, so it will be functioning in a relatively hypothermic environment.”

Transplantation remains the gold standard for patients with advanced heart failure despite modern medical and device therapy, Dr. Allen agreed. But “if we can raise pig hearts that provide the organ, and it can be implanted with a surgery that’s been done for 50 years, and rejection can be managed with gene editing and tailored immunosuppression, then it’s not hard to think about this very rapidly replacing a lot of what we do in the advanced heart failure and transplantation world.”

Certainly, it would be a major advance if the gene editing technique successfully improves the heart’s immunologic compatibility, Dr. Yancy noted. But do we have enough genomic knowledge to select gene deletions and insertions in the safest way for a successful outcome? “We have to appreciate that this is still a nascent technology, and we should be careful that there might be consequences that we haven’t anticipated.”

For example, he said, the xenotransplantation and gene-modifying techniques should be explored in a range of patients, including older and younger people, women and men, and people of different ethnicities and races.

“There may be some differences based on ancestry, based on gender, based on aging, that will influence the way in which these engineered donor hearts are experienced clinically,” Dr. Yancy said.

The xenotransplantation technique’s potential impact on health equity should also be considered, as it “almost assuredly will be a very expensive technology that will be utilized in a very select population,” he noted. “We need to have a really wide lens to think about all of the potential ramifications.”
 

‘This field needs to evolve’

Dr. Mehra also flagged the procedure’s potential cost should it become mainstream. Perhaps that would promote dialogue on how to primarily use it “after legitimately exhausting all available options, such as total artificial heart support.”

It might also teach the field to take greater advantage of the many donated hearts discarded as suboptimal. “The general usage rate for offered organs is around a third,” despite opportunities to expand use of those that are “less than perfect,” Dr. Mehra said. “I think that the field will grow with the community focusing on reduced discards of current available heart organs, and not necessarily grow because of the availability of ‘xeno-organs.’ ”

“This field needs to evolve because we’re actively transplanting patients today. But in my mind, the real future is to have such a sufficient understanding of the biology of left ventricular dysfunction that transplantation is a rare event,” Dr. Yancy proposed.

“I’m not certain that heart transplantation per se is the endgame. I think the avoidance of transplantation is the real endgame,” he said. “This may be controversial, but my vision of the future is not one where we have a supply of animals that we can use for transplantation. My vision of the future is that heart transplantation becomes obsolete.”

A version of this article first appeared on Medscape.com.

A genetically modified pig heart has been successfully transplanted into a 57-year-old man who had no other treatment options but is “doing well” 3 days after the procedure, officials at the University of Maryland Medical Center (UMMC), Baltimore, announced Jan. 10.

“This organ transplant demonstrated for the first time that a genetically modified animal heart can function like a human heart without immediate rejection by the body,” they said.

Three genes associated with antibody-mediated rejection had been knocked out in the pig supplying the transplanted heart, and six human genes associated with immune acceptance of the organ had been inserted into the pig’s genome, notes a UMMC press release.

University of Maryland Medical Center

A version of this article first appeared on Medscape.com.

A genetically modified pig heart has been successfully transplanted into a 57-year-old man who had no other treatment options but is “doing well” 3 days after the procedure, officials at the University of Maryland Medical Center (UMMC), Baltimore, announced Jan. 10.

“This organ transplant demonstrated for the first time that a genetically modified animal heart can function like a human heart without immediate rejection by the body,” they said.

Three genes associated with antibody-mediated rejection had been knocked out in the pig supplying the transplanted heart, and six human genes associated with immune acceptance of the organ had been inserted into the pig’s genome, notes a UMMC press release.

University of Maryland Medical Center

A version of this article first appeared on Medscape.com.

A genetically modified pig heart has been successfully transplanted into a 57-year-old man who had no other treatment options but is “doing well” 3 days after the procedure, officials at the University of Maryland Medical Center (UMMC), Baltimore, announced Jan. 10.

“This organ transplant demonstrated for the first time that a genetically modified animal heart can function like a human heart without immediate rejection by the body,” they said.

Three genes associated with antibody-mediated rejection had been knocked out in the pig supplying the transplanted heart, and six human genes associated with immune acceptance of the organ had been inserted into the pig’s genome, notes a UMMC press release.

University of Maryland Medical Center

A version of this article first appeared on Medscape.com.

The risk of myocarditis after immunization with mRNA-based vaccines against SARS-CoV-2 raised concerns when it came to light in early 2021. But as report after report showed such cases to be rare and usually mild and self-limited, focus has turned to the “how and why.”  

The mechanism linking the BNT162b2 (Pfizer-BioNTech) and especially mRNA-1273 (Moderna) vaccines to the occurrence of myocarditis is unclear for now, but one potential driver may be tied to a peculiarity that became apparent early: It occurs overwhelmingly in younger males, from 16 to perhaps 40 or 50 years of age. Excess risk has not been consistently seen among women, girls, and older men.

peterschreiber_media/iStock/Getty Images

That observation has led to speculation that higher testosterone levels in adolescent boys and young men may somehow promote the adverse vaccine effect, whereas greater levels of estrogen among girls and women in the same age range may be cardioprotective.
 

Unlikely, brief, and ‘benign’

“Most of the myocarditis is benign, by which I mean that maybe the patients are admitted due to chest pain, but without reduction in ventricular function,” Enrico Ammirati, MD, PhD, a myocarditis expert at De Gasperis Cardio Center and Transplant Center, Niguarda Hospital, Milan, said in an interview.

In a Nov. 14 address on this topic at the annual scientific sessions of the American Heart Association, Dror Mevorach, MD, described the typical case presentation as “mild” and one that clears in fairly short order based on resolution of “clinical symptoms, inflammatory markers and troponin decline, EKG normalization, echo normalization, and a relatively short length of hospital stay.”

Dr. Mevorach, of Hadassah Hebrew University Medical Center, Jerusalem, subsequently published the findings in a report in the New England Journal of Medicine that described 136 confirmed myocarditis cases among more than 5 million people in Israel immunized with the Pfizer-BioNTech vaccine. Myocarditis was considered “mild” in 129 cases, or 95%.

And the risk is tiny, compared with myocarditis from infection by SARS-CoV-2, not to mention the possibility of nasty clinical COVID-19 complications such as pneumonia and pulmonary embolism, Dr. Mevorach observed.

Many other reports agree that the incidence is minimal, especially given the rewards of vaccination. In a separate NEJM publication in September 2021 – from Noam Barda, MD, Clalit (Israel) Research Institute, and colleagues on 1.7 million people in that country, about half unvaccinated and half given the Pfizer-BioNTech vaccine – there were an estimated 2.7 cases of  myocarditis per 100,000 vaccinated persons. There were also 11 cases of myocarditis per 100,000 persons who were positive for SARS-CoV-2 infection.

And in a recent case series of vaccinated people aged 16 or older, the myocarditis rate after a first or second Pfizer-BioNTech or Moderna injection was estimated at 1 or fewer per 100,000. The corresponding estimate was 4 such cases per 100,000 after a positive SARS-CoV-2 test among the same population, notes a report published Dec.14, 2021, in Nature Medicine.

In general, “the risk of any kind of cardiac injury is vastly lower with a vaccine than it is with the actual viral infection,” Leslie T. Cooper Jr., MD, a myocarditis expert and clinical trialist at the Mayo Clinic, Jacksonville, Fla., said in an interview. With the mRNA-based vaccines, “we do not have any conceivable danger signal that would outweigh the benefit of vaccination.”
 

Males of a certain age

Evidence that such myocarditis predominates in young adult men and adolescent boys, especially following a second vaccine dose, is remarkably consistent.

The risk was elevated only among mRNA-based vaccine recipients who were younger than 40 in the recent Nature Medicine analysis. Among that group, estimates after a second dose numbered fewer than 1 case per 100,000 for Pfizer-BioNTech and 1.5 per 100,000 for Moderna.

In a third analysis from Israel – also in NEJM, from Guy Witberg, MD, Rabin Medical Center, Petah Tikva, and colleagues, based on 2.5 million people aged 16 and older with at least one Pfizer-BioNTech injection – 2.1 cases per 100,000 were estimated overall, but the number rose to 10.7 per 100,000 among those aged 16-29 years.

In Dr. Mevorach’s NEJM report, estimates after a second Pfizer-BioNTech vaccine dose were 1 per 26,000 males versus 1 in 218,000 females, compared with 1 myocarditis case in 10,857 persons among “the general unvaccinated population.”

Most recipients of a first vaccine dose were younger than 50, and 16- to 29-year-olds accounted for most who completed two doses, noted Dr. Mevorach. Younger males bore the brunt of any myocarditis: the estimated prevalence after a second dose among males aged 16-19 was 1 per 6,637, compared with 1 per 99,853 females in the same age range, the group reported.

In the BMJ report, based on about 5 million people 12 years of age or older in Denmark, the estimated rates of myocarditis or pericarditis associated with Moderna immunization were 2 per 100,000 among women but 6.3 per 100,000 for men. The incidence and sex difference was much lower among those getting the Pfizer-BioNTech vaccine: 1.3 per 100,000 and 1.5 per 100,000 in women and men, respectively.
 

Sex hormones may be key

The predominance of vaccine-associated myocarditis among adolescent and young adult males is probably more about the myocarditis itself than the vaccines, observed Biykem Bozkurt, MD, PhD, who has been studying COVID-related myocarditis at Baylor College of Medicine, Houston.

Male sex historically is associated in both epidemiologic studies and experimental models with a greater propensity for most any form of myocarditis, Dr. Bozkurt said in an interview. Given that males aged 16-19 or so appear to be at highest risk of myocarditis as a complication of SARS-CoV-2 vaccination, the mechanism may well be related to sex hormones.  

“Therefore, testosterone is implicated as a player in their higher risk of inflammation and injury and lack of adaptive response in terms of healing, and in terms of prevention of injury,” Dr. Bozkurt said. For its part, estrogen inhibits proinflammatory processes and, in particular, “blunts cell-mediated immune responses.”

“We don’t know the mechanism, but a theory that attributes a protective role to estrogen, or a risk associated with testosterone, is reasonable. It makes sense, at least based on epidemiological data,” Dr. Ammirati agreed. Still, “we do not have any direct evidence in human beings.”

Sex-associated differences in experimental myocarditis have been reported in the journals for at least 70 years, but “the testosterone literature and the estrogen literature have not been evaluated in detail in vaccine-associated myocarditis,” Dr. Cooper said.

Most myocarditis in the laboratory is viral, Dr. Cooper observed, and “the links between testosterone, viruses, and inflammation have been pretty well worked out, I would say, if you’re a mouse. If you’re a human, I think it’s still a bit uncertain.”

Were it to apply in humans, greater testosterone levels might independently promote myocarditis, “and if estrogen is cardioprotective, it would be another mechanism,” Dr. Cooper said. “That would translate to slight male predominance in most kinds of myocarditis.”

In males, compared with females, “the heart can be more vulnerable to events such as arrhythmias or to immune-mediated phenomena. So, probably there is also higher vulnerability to myocarditis in men,” Dr. Ammirati noted.

Male predominance in vaccine-related myocarditis is provocative, so it’s worth considering whether testosterone is part of the mechanism as well as the possibility of estrogen cardioprotection, Dr. Ammirati said. But given limitations of the animal models, “we don’t really have robust data to support any part of that.”

Although myocarditis is in some way immune mediated, “and hormones can modulate the response,” the mechanism has to be more than just sex hormones, he said. “They probably cannot explain the specificity for the heart. It’s not a systemic response, it’s an organ-specific response.”
 

Modulation of immune responses

Details about the immune processes underlying mRNA-vaccine myocarditis, hormone modulated or not, have been elusive. The complication doesn’t resemble serum sickness, nor does it seem to be a reaction to infection by other cardiotropic viruses, such as coxsackie virus B, a cause of viral myocarditis, Dr. Bozkurt said. The latter had been a compelling possibility because such hypersensitivity to smallpox vaccination is well recognized.

“We don’t know the mechanism, that’s the short answer. But there are many hypotheses,” she said. One candidate widely proposed in the literature: autoantibodies driven by molecular mimicry between the SARS-CoV-2 spike protein targeted by the mRNA vaccines and a structurally similar myocardial protein, possibly alpha-myosin, noted Dr. Bozkurt and colleagues in a recent publication.

But elevations in specific “antiheart antibodies” have not been documented in recipients of the two mRNA-based vaccines, said Dr. Cooper. “So, I would say that – although molecular mimicry is a well-established mechanism of, for example, rheumatic carditis after a streptococcal A infection – that has not been demonstrated yet for COVID-19 mRNA vaccination–related myocarditis.”

“We probably won’t know, ever, with a huge level of certainty, the exact mechanisms,” Dr. Cooper added. There is no animal model for vaccine-induced myocarditis, and “We’re still talking very, very small numbers of patients. The vast majority of them recover,” and so don’t generally provide mechanistic clues.  
 

Prospects for younger children

Vaccination against SARS-CoV-2 has now been authorized by the Centers for Disease Control and Prevention for kids as young as 5-11 years, using the Pfizer-BioNTech vaccine. Experience so far suggests the immunization is safe in that age group with negligible risk of myocarditis or other complications. But with prospects of possible authorization in children younger than 5, should myocarditis be a concern for them?

Probably not, if the complication is driven primarily by sex hormones, Dr. Cooper proposed. “One would predict that before puberty you would have a lower – much, much lower – rate of myocarditis in males than you would in the 16- to 19-year-old range, and that it would be roughly equal to females.” Dr. Ammirati and Dr. Bozkurt largely agreed.

It remains to be seen whether the vaccine-related myocarditis risk applies to children younger than 12, “but I doubt it. I think it’s going to be puberty-related,” Dr. Bozkurt said. Still, “I don’t want to hypothesize without data.”

A version of this article first appeared on Medscape.com.

The risk of myocarditis after immunization with mRNA-based vaccines against SARS-CoV-2 raised concerns when it came to light in early 2021. But as report after report showed such cases to be rare and usually mild and self-limited, focus has turned to the “how and why.”  

The mechanism linking the BNT162b2 (Pfizer-BioNTech) and especially mRNA-1273 (Moderna) vaccines to the occurrence of myocarditis is unclear for now, but one potential driver may be tied to a peculiarity that became apparent early: It occurs overwhelmingly in younger males, from 16 to perhaps 40 or 50 years of age. Excess risk has not been consistently seen among women, girls, and older men.

peterschreiber_media/iStock/Getty Images

That observation has led to speculation that higher testosterone levels in adolescent boys and young men may somehow promote the adverse vaccine effect, whereas greater levels of estrogen among girls and women in the same age range may be cardioprotective.
 

Unlikely, brief, and ‘benign’

“Most of the myocarditis is benign, by which I mean that maybe the patients are admitted due to chest pain, but without reduction in ventricular function,” Enrico Ammirati, MD, PhD, a myocarditis expert at De Gasperis Cardio Center and Transplant Center, Niguarda Hospital, Milan, said in an interview.

In a Nov. 14 address on this topic at the annual scientific sessions of the American Heart Association, Dror Mevorach, MD, described the typical case presentation as “mild” and one that clears in fairly short order based on resolution of “clinical symptoms, inflammatory markers and troponin decline, EKG normalization, echo normalization, and a relatively short length of hospital stay.”

Dr. Mevorach, of Hadassah Hebrew University Medical Center, Jerusalem, subsequently published the findings in a report in the New England Journal of Medicine that described 136 confirmed myocarditis cases among more than 5 million people in Israel immunized with the Pfizer-BioNTech vaccine. Myocarditis was considered “mild” in 129 cases, or 95%.

And the risk is tiny, compared with myocarditis from infection by SARS-CoV-2, not to mention the possibility of nasty clinical COVID-19 complications such as pneumonia and pulmonary embolism, Dr. Mevorach observed.

Many other reports agree that the incidence is minimal, especially given the rewards of vaccination. In a separate NEJM publication in September 2021 – from Noam Barda, MD, Clalit (Israel) Research Institute, and colleagues on 1.7 million people in that country, about half unvaccinated and half given the Pfizer-BioNTech vaccine – there were an estimated 2.7 cases of  myocarditis per 100,000 vaccinated persons. There were also 11 cases of myocarditis per 100,000 persons who were positive for SARS-CoV-2 infection.

And in a recent case series of vaccinated people aged 16 or older, the myocarditis rate after a first or second Pfizer-BioNTech or Moderna injection was estimated at 1 or fewer per 100,000. The corresponding estimate was 4 such cases per 100,000 after a positive SARS-CoV-2 test among the same population, notes a report published Dec.14, 2021, in Nature Medicine.

In general, “the risk of any kind of cardiac injury is vastly lower with a vaccine than it is with the actual viral infection,” Leslie T. Cooper Jr., MD, a myocarditis expert and clinical trialist at the Mayo Clinic, Jacksonville, Fla., said in an interview. With the mRNA-based vaccines, “we do not have any conceivable danger signal that would outweigh the benefit of vaccination.”
 

Males of a certain age

Evidence that such myocarditis predominates in young adult men and adolescent boys, especially following a second vaccine dose, is remarkably consistent.

The risk was elevated only among mRNA-based vaccine recipients who were younger than 40 in the recent Nature Medicine analysis. Among that group, estimates after a second dose numbered fewer than 1 case per 100,000 for Pfizer-BioNTech and 1.5 per 100,000 for Moderna.

In a third analysis from Israel – also in NEJM, from Guy Witberg, MD, Rabin Medical Center, Petah Tikva, and colleagues, based on 2.5 million people aged 16 and older with at least one Pfizer-BioNTech injection – 2.1 cases per 100,000 were estimated overall, but the number rose to 10.7 per 100,000 among those aged 16-29 years.

In Dr. Mevorach’s NEJM report, estimates after a second Pfizer-BioNTech vaccine dose were 1 per 26,000 males versus 1 in 218,000 females, compared with 1 myocarditis case in 10,857 persons among “the general unvaccinated population.”

Most recipients of a first vaccine dose were younger than 50, and 16- to 29-year-olds accounted for most who completed two doses, noted Dr. Mevorach. Younger males bore the brunt of any myocarditis: the estimated prevalence after a second dose among males aged 16-19 was 1 per 6,637, compared with 1 per 99,853 females in the same age range, the group reported.

In the BMJ report, based on about 5 million people 12 years of age or older in Denmark, the estimated rates of myocarditis or pericarditis associated with Moderna immunization were 2 per 100,000 among women but 6.3 per 100,000 for men. The incidence and sex difference was much lower among those getting the Pfizer-BioNTech vaccine: 1.3 per 100,000 and 1.5 per 100,000 in women and men, respectively.
 

Sex hormones may be key

The predominance of vaccine-associated myocarditis among adolescent and young adult males is probably more about the myocarditis itself than the vaccines, observed Biykem Bozkurt, MD, PhD, who has been studying COVID-related myocarditis at Baylor College of Medicine, Houston.

Male sex historically is associated in both epidemiologic studies and experimental models with a greater propensity for most any form of myocarditis, Dr. Bozkurt said in an interview. Given that males aged 16-19 or so appear to be at highest risk of myocarditis as a complication of SARS-CoV-2 vaccination, the mechanism may well be related to sex hormones.  

“Therefore, testosterone is implicated as a player in their higher risk of inflammation and injury and lack of adaptive response in terms of healing, and in terms of prevention of injury,” Dr. Bozkurt said. For its part, estrogen inhibits proinflammatory processes and, in particular, “blunts cell-mediated immune responses.”

“We don’t know the mechanism, but a theory that attributes a protective role to estrogen, or a risk associated with testosterone, is reasonable. It makes sense, at least based on epidemiological data,” Dr. Ammirati agreed. Still, “we do not have any direct evidence in human beings.”

Sex-associated differences in experimental myocarditis have been reported in the journals for at least 70 years, but “the testosterone literature and the estrogen literature have not been evaluated in detail in vaccine-associated myocarditis,” Dr. Cooper said.

Most myocarditis in the laboratory is viral, Dr. Cooper observed, and “the links between testosterone, viruses, and inflammation have been pretty well worked out, I would say, if you’re a mouse. If you’re a human, I think it’s still a bit uncertain.”

Were it to apply in humans, greater testosterone levels might independently promote myocarditis, “and if estrogen is cardioprotective, it would be another mechanism,” Dr. Cooper said. “That would translate to slight male predominance in most kinds of myocarditis.”

In males, compared with females, “the heart can be more vulnerable to events such as arrhythmias or to immune-mediated phenomena. So, probably there is also higher vulnerability to myocarditis in men,” Dr. Ammirati noted.

Male predominance in vaccine-related myocarditis is provocative, so it’s worth considering whether testosterone is part of the mechanism as well as the possibility of estrogen cardioprotection, Dr. Ammirati said. But given limitations of the animal models, “we don’t really have robust data to support any part of that.”

Although myocarditis is in some way immune mediated, “and hormones can modulate the response,” the mechanism has to be more than just sex hormones, he said. “They probably cannot explain the specificity for the heart. It’s not a systemic response, it’s an organ-specific response.”
 

Modulation of immune responses

Details about the immune processes underlying mRNA-vaccine myocarditis, hormone modulated or not, have been elusive. The complication doesn’t resemble serum sickness, nor does it seem to be a reaction to infection by other cardiotropic viruses, such as coxsackie virus B, a cause of viral myocarditis, Dr. Bozkurt said. The latter had been a compelling possibility because such hypersensitivity to smallpox vaccination is well recognized.

“We don’t know the mechanism, that’s the short answer. But there are many hypotheses,” she said. One candidate widely proposed in the literature: autoantibodies driven by molecular mimicry between the SARS-CoV-2 spike protein targeted by the mRNA vaccines and a structurally similar myocardial protein, possibly alpha-myosin, noted Dr. Bozkurt and colleagues in a recent publication.

But elevations in specific “antiheart antibodies” have not been documented in recipients of the two mRNA-based vaccines, said Dr. Cooper. “So, I would say that – although molecular mimicry is a well-established mechanism of, for example, rheumatic carditis after a streptococcal A infection – that has not been demonstrated yet for COVID-19 mRNA vaccination–related myocarditis.”

“We probably won’t know, ever, with a huge level of certainty, the exact mechanisms,” Dr. Cooper added. There is no animal model for vaccine-induced myocarditis, and “We’re still talking very, very small numbers of patients. The vast majority of them recover,” and so don’t generally provide mechanistic clues.  
 

Prospects for younger children

Vaccination against SARS-CoV-2 has now been authorized by the Centers for Disease Control and Prevention for kids as young as 5-11 years, using the Pfizer-BioNTech vaccine. Experience so far suggests the immunization is safe in that age group with negligible risk of myocarditis or other complications. But with prospects of possible authorization in children younger than 5, should myocarditis be a concern for them?

Probably not, if the complication is driven primarily by sex hormones, Dr. Cooper proposed. “One would predict that before puberty you would have a lower – much, much lower – rate of myocarditis in males than you would in the 16- to 19-year-old range, and that it would be roughly equal to females.” Dr. Ammirati and Dr. Bozkurt largely agreed.

It remains to be seen whether the vaccine-related myocarditis risk applies to children younger than 12, “but I doubt it. I think it’s going to be puberty-related,” Dr. Bozkurt said. Still, “I don’t want to hypothesize without data.”

A version of this article first appeared on Medscape.com.

The risk of myocarditis after immunization with mRNA-based vaccines against SARS-CoV-2 raised concerns when it came to light in early 2021. But as report after report showed such cases to be rare and usually mild and self-limited, focus has turned to the “how and why.”  

The mechanism linking the BNT162b2 (Pfizer-BioNTech) and especially mRNA-1273 (Moderna) vaccines to the occurrence of myocarditis is unclear for now, but one potential driver may be tied to a peculiarity that became apparent early: It occurs overwhelmingly in younger males, from 16 to perhaps 40 or 50 years of age. Excess risk has not been consistently seen among women, girls, and older men.

peterschreiber_media/iStock/Getty Images

That observation has led to speculation that higher testosterone levels in adolescent boys and young men may somehow promote the adverse vaccine effect, whereas greater levels of estrogen among girls and women in the same age range may be cardioprotective.
 

Unlikely, brief, and ‘benign’

“Most of the myocarditis is benign, by which I mean that maybe the patients are admitted due to chest pain, but without reduction in ventricular function,” Enrico Ammirati, MD, PhD, a myocarditis expert at De Gasperis Cardio Center and Transplant Center, Niguarda Hospital, Milan, said in an interview.

In a Nov. 14 address on this topic at the annual scientific sessions of the American Heart Association, Dror Mevorach, MD, described the typical case presentation as “mild” and one that clears in fairly short order based on resolution of “clinical symptoms, inflammatory markers and troponin decline, EKG normalization, echo normalization, and a relatively short length of hospital stay.”

Dr. Mevorach, of Hadassah Hebrew University Medical Center, Jerusalem, subsequently published the findings in a report in the New England Journal of Medicine that described 136 confirmed myocarditis cases among more than 5 million people in Israel immunized with the Pfizer-BioNTech vaccine. Myocarditis was considered “mild” in 129 cases, or 95%.

And the risk is tiny, compared with myocarditis from infection by SARS-CoV-2, not to mention the possibility of nasty clinical COVID-19 complications such as pneumonia and pulmonary embolism, Dr. Mevorach observed.

Many other reports agree that the incidence is minimal, especially given the rewards of vaccination. In a separate NEJM publication in September 2021 – from Noam Barda, MD, Clalit (Israel) Research Institute, and colleagues on 1.7 million people in that country, about half unvaccinated and half given the Pfizer-BioNTech vaccine – there were an estimated 2.7 cases of  myocarditis per 100,000 vaccinated persons. There were also 11 cases of myocarditis per 100,000 persons who were positive for SARS-CoV-2 infection.

And in a recent case series of vaccinated people aged 16 or older, the myocarditis rate after a first or second Pfizer-BioNTech or Moderna injection was estimated at 1 or fewer per 100,000. The corresponding estimate was 4 such cases per 100,000 after a positive SARS-CoV-2 test among the same population, notes a report published Dec.14, 2021, in Nature Medicine.

In general, “the risk of any kind of cardiac injury is vastly lower with a vaccine than it is with the actual viral infection,” Leslie T. Cooper Jr., MD, a myocarditis expert and clinical trialist at the Mayo Clinic, Jacksonville, Fla., said in an interview. With the mRNA-based vaccines, “we do not have any conceivable danger signal that would outweigh the benefit of vaccination.”
 

Males of a certain age

Evidence that such myocarditis predominates in young adult men and adolescent boys, especially following a second vaccine dose, is remarkably consistent.

The risk was elevated only among mRNA-based vaccine recipients who were younger than 40 in the recent Nature Medicine analysis. Among that group, estimates after a second dose numbered fewer than 1 case per 100,000 for Pfizer-BioNTech and 1.5 per 100,000 for Moderna.

In a third analysis from Israel – also in NEJM, from Guy Witberg, MD, Rabin Medical Center, Petah Tikva, and colleagues, based on 2.5 million people aged 16 and older with at least one Pfizer-BioNTech injection – 2.1 cases per 100,000 were estimated overall, but the number rose to 10.7 per 100,000 among those aged 16-29 years.

In Dr. Mevorach’s NEJM report, estimates after a second Pfizer-BioNTech vaccine dose were 1 per 26,000 males versus 1 in 218,000 females, compared with 1 myocarditis case in 10,857 persons among “the general unvaccinated population.”

Most recipients of a first vaccine dose were younger than 50, and 16- to 29-year-olds accounted for most who completed two doses, noted Dr. Mevorach. Younger males bore the brunt of any myocarditis: the estimated prevalence after a second dose among males aged 16-19 was 1 per 6,637, compared with 1 per 99,853 females in the same age range, the group reported.

In the BMJ report, based on about 5 million people 12 years of age or older in Denmark, the estimated rates of myocarditis or pericarditis associated with Moderna immunization were 2 per 100,000 among women but 6.3 per 100,000 for men. The incidence and sex difference was much lower among those getting the Pfizer-BioNTech vaccine: 1.3 per 100,000 and 1.5 per 100,000 in women and men, respectively.
 

Sex hormones may be key

The predominance of vaccine-associated myocarditis among adolescent and young adult males is probably more about the myocarditis itself than the vaccines, observed Biykem Bozkurt, MD, PhD, who has been studying COVID-related myocarditis at Baylor College of Medicine, Houston.

Male sex historically is associated in both epidemiologic studies and experimental models with a greater propensity for most any form of myocarditis, Dr. Bozkurt said in an interview. Given that males aged 16-19 or so appear to be at highest risk of myocarditis as a complication of SARS-CoV-2 vaccination, the mechanism may well be related to sex hormones.  

“Therefore, testosterone is implicated as a player in their higher risk of inflammation and injury and lack of adaptive response in terms of healing, and in terms of prevention of injury,” Dr. Bozkurt said. For its part, estrogen inhibits proinflammatory processes and, in particular, “blunts cell-mediated immune responses.”

“We don’t know the mechanism, but a theory that attributes a protective role to estrogen, or a risk associated with testosterone, is reasonable. It makes sense, at least based on epidemiological data,” Dr. Ammirati agreed. Still, “we do not have any direct evidence in human beings.”

Sex-associated differences in experimental myocarditis have been reported in the journals for at least 70 years, but “the testosterone literature and the estrogen literature have not been evaluated in detail in vaccine-associated myocarditis,” Dr. Cooper said.

Most myocarditis in the laboratory is viral, Dr. Cooper observed, and “the links between testosterone, viruses, and inflammation have been pretty well worked out, I would say, if you’re a mouse. If you’re a human, I think it’s still a bit uncertain.”

Were it to apply in humans, greater testosterone levels might independently promote myocarditis, “and if estrogen is cardioprotective, it would be another mechanism,” Dr. Cooper said. “That would translate to slight male predominance in most kinds of myocarditis.”

In males, compared with females, “the heart can be more vulnerable to events such as arrhythmias or to immune-mediated phenomena. So, probably there is also higher vulnerability to myocarditis in men,” Dr. Ammirati noted.

Male predominance in vaccine-related myocarditis is provocative, so it’s worth considering whether testosterone is part of the mechanism as well as the possibility of estrogen cardioprotection, Dr. Ammirati said. But given limitations of the animal models, “we don’t really have robust data to support any part of that.”

Although myocarditis is in some way immune mediated, “and hormones can modulate the response,” the mechanism has to be more than just sex hormones, he said. “They probably cannot explain the specificity for the heart. It’s not a systemic response, it’s an organ-specific response.”
 

Modulation of immune responses

Details about the immune processes underlying mRNA-vaccine myocarditis, hormone modulated or not, have been elusive. The complication doesn’t resemble serum sickness, nor does it seem to be a reaction to infection by other cardiotropic viruses, such as coxsackie virus B, a cause of viral myocarditis, Dr. Bozkurt said. The latter had been a compelling possibility because such hypersensitivity to smallpox vaccination is well recognized.

“We don’t know the mechanism, that’s the short answer. But there are many hypotheses,” she said. One candidate widely proposed in the literature: autoantibodies driven by molecular mimicry between the SARS-CoV-2 spike protein targeted by the mRNA vaccines and a structurally similar myocardial protein, possibly alpha-myosin, noted Dr. Bozkurt and colleagues in a recent publication.

But elevations in specific “antiheart antibodies” have not been documented in recipients of the two mRNA-based vaccines, said Dr. Cooper. “So, I would say that – although molecular mimicry is a well-established mechanism of, for example, rheumatic carditis after a streptococcal A infection – that has not been demonstrated yet for COVID-19 mRNA vaccination–related myocarditis.”

“We probably won’t know, ever, with a huge level of certainty, the exact mechanisms,” Dr. Cooper added. There is no animal model for vaccine-induced myocarditis, and “We’re still talking very, very small numbers of patients. The vast majority of them recover,” and so don’t generally provide mechanistic clues.  
 

Prospects for younger children

Vaccination against SARS-CoV-2 has now been authorized by the Centers for Disease Control and Prevention for kids as young as 5-11 years, using the Pfizer-BioNTech vaccine. Experience so far suggests the immunization is safe in that age group with negligible risk of myocarditis or other complications. But with prospects of possible authorization in children younger than 5, should myocarditis be a concern for them?

Probably not, if the complication is driven primarily by sex hormones, Dr. Cooper proposed. “One would predict that before puberty you would have a lower – much, much lower – rate of myocarditis in males than you would in the 16- to 19-year-old range, and that it would be roughly equal to females.” Dr. Ammirati and Dr. Bozkurt largely agreed.

It remains to be seen whether the vaccine-related myocarditis risk applies to children younger than 12, “but I doubt it. I think it’s going to be puberty-related,” Dr. Bozkurt said. Still, “I don’t want to hypothesize without data.”

A version of this article first appeared on Medscape.com.