No Benefit of Anti-inflammatory Strategy in Acute Myocarditis

September 06, 2023

AMSTERDAM — A short course of the interleukin-1 receptor antagonist, anakinra, appeared safe but did not reduce complications of acute myocarditis in the ARAMIS trial.

The trial was presented at the European Society of Cardiology (ESC) Congress 2023 held recently in Amsterdam, the Netherlands.

Lead investigator, Mathieu Kerneis, MD, Pitie Salpetriere APHP University Hospital, Paris, France, said this was the largest randomized controlled trial of patients with acute myocarditis and probably the first ever study in the acute setting of myocarditis patients diagnosed with cardiac magnetic resonance (CMR) imaging, not on biopsy, who are mostly at low risk for events.

He suggested that one of the reasons for the neutral result could have been the low-risk population involved and the low complication rate. "We enrolled an all-comer acute myocarditis population diagnosed with CMR, who were mostly at a low risk of complications," he noted.

"I don't think the story of anti-inflammatory drugs in acute myocarditis is over. This is just the beginning. This was the first trial, and it was just a phase 2 trial. We need further randomized trials to explore the potential benefit of an anti-inflammatory strategy in acute myocarditis patients at higher risk of complications. In addition, larger studies are needed to evaluate prolonged anti-inflammatory strategies in acute myocarditis patients at low-to-moderate risk of complications," Kerneis concluded.

"It is very challenging to do a trial in high-risk patients with myocarditis as these patients are quite rare," he added.

Inflammation of the Myocardium

Kerneis explained that acute myocarditis is an inflammation of the myocardium that can cause permanent damage to the heart muscle and lead to myocardial infarction, stroke, heart failure, arrhythmias, and death. The condition can occur in individuals of all ages but is most frequent in young people. There is no specific treatment, but patients are generally treated with beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and sometimes steroids.

Anakinra is an interleukin-1 receptor antagonist that works by targeting the interleukin-1β innate immune pathway. Anakinra is used for the treatment of rheumatoid arthritis and has shown efficacy in pericarditis. Kerneis noted that there have been several case reports of successful treatment with anakinra in acute myocarditis.

The ARAMIS trial — conducted at six academic centers in France — was the first randomized study to evaluate inhibition of the interleukin-1β innate immune pathway in myocarditis patients. The trial enrolled 120 hospitalized, symptomatic patients with chest pain, increased cardiac troponin, and acute myocarditis diagnosed using CMR. More than half had had a recent bacterial or viral infection.

Patients were randomized within 72 hours of hospital admission to a daily subcutaneous dose of anakinra 100 mg or placebo until hospital discharge. Patients in both groups received standard-of-care treatments, including an ACE inhibitor, for at least 1 month. Consistent with prior data, the median age of participants was 28 years and 90% were men.

The primary endpoint was the number of days free of myocarditis complications (heart failure requiring hospitalization, chest pain requiring medication, left ventricular ejection fraction less than 50%, and ventricular arrhythmias) within 28 days postdischarge.

There was no significant difference in this endpoint between the two arms, with a median of 30 days for anakinra versus 31 days for placebo.

Overall, the rate of the composite endpoint of myocarditis complications occurred in 13.7% of patients, and there was a numerical reduction in the number of patients with these myocarditis complications with anakinra — six patients (10.5%) in the anakinra group versus 10 patients (16.5%) in the placebo group (odds ratio, 0.59; 95% confidence interval, 0.19 - 1.78). This was driven by fewer patients with chest pain requiring new medication (two patients versus six patients).

The safety endpoint was the number of serious adverse events within 28 days postdischarge. This endpoint occurred in seven patients (12.1%) in the anakinra arm and six patients (10.2%) in the placebo arm, with no significant difference between groups. Cases of severe infection within 28 days postdischarge were reported in both arms.

Low-risk Population

Designated discussant of the study at the ESC Hotline session, Enrico Ammirati, MD, PhD, University of Milano-Bicocca, Monza, Italy, said that patients involved in ARAMIS fit the profile of acute myocarditis and that the CMR diagnosis was positive in all the patients enrolled.

Ammirati agreed with Kerneis that the neutral results of the study were probably caused by the low-risk population. "If we look at retrospective registries, at 30 days there are zero cardiac deaths or heart transplants at 30 days in patients with a low-risk presentation."

"The ARAMIS trial has shown the feasibility of conducting studies in the setting of acute myocarditis, and even if the primary endpoint was neutral, some important data are still missing, such as change in ejection fraction and troponin levels," he noted.

"In terms of future perspective, we are moving to assessing efficacy of anakinra or other immunosuppressive drugs from acute low risk patients to higher risk patients with heart failure and severe dysfunction," he said.  

Ammirati is the lead investigator of another ongoing study in such a higher-risk population; the MYTHS trial is investigating the use of intravenous steroids in patients with suspected acute myocarditis complicated by acute heart failure or cardiogenic shock, and an ejection fraction below 41%.

"So, we will have more results on the best treatment in this higher risk group of patients," he concluded.

European Society of Cardiology (ESC) Congress 2023. Presented August 28.

The ARAMIS Trial was an academic study funded by the French Health Ministry and coordinated by the ACTION Group. Kerneis reports having received consulting fees from Kiniksa, Sanofi, and Bayer, and holds a patent for use of abatacept in i mmune checkpoint inhibitor (ICI) -induced myocarditis.

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