Anakinra in pediatric acute fulminant myocarditis

Acute fulminant myocarditis in children is associated with elevated mortality and morbidity with few advances in its medical management. In adults with acute myocarditis, activation of the inflammasome through the production of pro-inflammatory mediators such IL-1β, IL-18 is widely recognized. Here we report a preliminary experience of children treated with IL-1 receptor antagonist associated with rapid myocardial function recovery. A retrospective case series of children admitted to the Pediatric Intensive Care Unit of Bicêtre Hospital (AP–HP Paris Saclay University) between April 2020 and January 2023 with acute myocarditis. Children were treated with subcutaneous Anakinra (an IL-1 receptor antagonist). Patients’ characteristics, and outcome are reported. Of twenty-four children admitted with acute fulminant myocarditis, fifteen were treated with sub-cutaneous anakinra. Twelve children had SARS-CoV-2 post-infective myocarditis associated with multisystem inflammatory syndrome in children (MIS-C), one child had Parvovirus B19 myocarditis, one child had idiopathic encephalomyelitis and myocarditis and one child had idiopathic myocarditis. Nine of fifteen children were in cardiogenic shock and needed vasopressor drugs, one required central extracorporeal membrane oxygenation (ECMO). Only three of the fifteen children had ventricular arrhythmia, one evolving toward malignant ventricular fibrillation. In all treated patients, a rapid (< 24 h) improvement in myocardial function was observed with concomitant decrease in myocardial enzymes. All patients survived with full myocardial recovery except from one who had a heart transplantation (Figure 1). In this pilot study, use of IL-1 receptor antagonist in the initial treatment of acute fulminant myocarditis in children seems to be associated with rapid stabilization and recovery.