Abbate, Antonio

BACKGROUND: No large registries of patients with acute eosinophilic myocarditis (EM) are available. However, EM is perceived as a cardiac disease with high mortality, affecting mainly young and middle-aged adults according to small series and case reports. Awareness of the clinical presentation, associated systemic conditions, treatments, and outcomes of this uncommon condition is an unmet need. METHODS: In this international, multicenter, retrospective cohort study, 53 centers screened 193 patients with histologically proven acute EM between 1992 and 2023. After the exclusion of patients with insufficient data (n=10), symptoms lasting >30 days (n=19), or histological diagnosis not confirmed after review (n=8), 156 patients were included. RESULTS: Median age at presentation was 48 years (first to third quartile, 34–59 years) with male predominance (67.3%), and only 2 were pediatric cases (≤16 years of age; 1.3%). The main signs and symptoms at presentation were dyspnea (75.6%), fever (61.3%), and chest pain (53.2%). Unexpectedly, peripheral eosinophilia was reported in only 57.4% of cases, with a median cell count of 630 eosinophils/μL. The median left ventricular ejection fraction at presentation was 32% (first to third quartile, 25%–48%). The disorders most frequently associated with EM were eosinophilic granulomatosis with polyangiitis (22.4% of cases) and hypersensitivity forms (14.1%). Idiopathic/undefined forms accounted for 44.9% of cases, and miscellaneous causes accounted for 18.6%. In-hospital death or need for heart transplantation (HTx) occurred in 23 patients (14.7%; 22 deaths and 1 HTx), despite 43.6% being treated with temporary mechanical circulatory support and 92.9% being treated with immunosuppressive agents. Estimated rates of death or HTx at 1 and 3 years were 19.0% and 23.8%. Increased age, decreased left ventricular ejection fraction on admission, and no immunosuppressive therapy during hospitalization were independent predictors of death or HTx. A nonsignificant higher occurrence of deaths or HTx was observed in the hypersensitivity form (46.1%) compared with the eosinophilic granulomatosis with polyangiitis–associated form (13.1%) at 3 years ( P =0.15). CONCLUSIONS: Acute EM can often present without peripheral eosinophilia, and rates of in-hospital and midterm mortality or HTx are high. Endomyocardial biopsy is required to reach the final diagnosis of EM because relying on peripheral eosinophilia can lead to missing diagnosis. In-hospital immunosuppression is associated with HTx-free survival, although tailored immunosuppressive therapies are needed to improve outcomes. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT06447935.

Abstract Background Recurrent pericarditis (RP) predominantly shows features consistent with IL-1-mediated chronic autoinflammatory disease (1-4). A recent analysis suggested that supplementing anakinra with colchicine incrementally reduced pericarditis recurrence vs. anakinra alone (5). Rilonacept (a weekly IL-1α and IL-1β cytokine trap with 6-week washout) prevents engagement with IL-1 receptor, inhibiting both IL-1α and IL-1β activity (6). The Phase 3 trial RHAPSODY demonstrated rilonacept efficacy in two independent analyses: Randomized Withdrawal (RW) and Long-Term Extension (LTE) periods (7,8). Purpose Assess long-term recurrence-free persistence with rilonacept as monotherapy in pts with RP during the combined RW and LTE periods of RHAPSODY. Methods Post-hoc analysis. Freedom from recurrence on rilonacept monotherapy was quantified using the Kaplan-Meier (KM) method from RW start (if randomized to rilonacept) or from initiation of bailout rilonacept (if randomized to placebo) until the end of treatment. Prespecified recurrence adjudication criteria were pericarditis pain (numerical rating scale [NRS]) ≥4 plus C-reactive protein (CRP) ≥1 mg/dL. Per RHAPSODY protocol, background therapies were discontinued during the Run-In Period before randomization. In pts treated with rilonacept, concomitant colchicine was not added during the RW period. In the LTE, 6.8% (5/74) of pts added colchicine: one for 2 days of chest pain without CRP elevation, 4 in the absence of chest pain, CRP elevation, or recurrence; these 5 pts were censored in the KM curve at 6 days after last rilonacept dose or at colchicine initiation (whichever was first). One additional pt added colchicine prophylactically before an intentional rilonacept treatment interruption for elective cardiac surgery and experienced a recurrence after this interruption; this pt was not censored from the recurrence-free persistence analysis at colchicine initiation in order to capture this event. Results 74 pts (mean [SD] age 43.9 [15.7] years, 83.8% idiopathic pericarditis, mean [SD] disease duration 2.5 [3.2] years) were analyzed over three years. Rilonacept was well tolerated. Recurrence-free persistence was 95.9% (n=71/74) while receiving rilonacept as monotherapy (Figure 1). The three observed adjudicated recurrences were each associated with temporary interruptions of 1-3 doses of rilonacept. Conclusions Rilonacept as monotherapy provided recurrence-free persistence over the three-year trial duration when used continuously without interruption; pericarditis recurrences occurred only after interruptions. These findings support evidence-based use of rilonacept as monotherapy, minimizing the need for adjunctive treatments and reducing polypharmacy in long-term RP management. Further investigations are warranted to address how to assess pts as candidates for long-term treatment with rilonacept and when to cease rilonacept treatment.