Pericardial late gadolinium enhancement and time to recurrence: a substudy from RHAPSODY, a phase 3 clinical trial of rilonacept in recurrent pericarditis.

Aims: In this protocol-predefined substudy of the RHAPSODY trial, the primary aim was to assess whether pericardial late gadolinium enhancement (LGE) was associated with time to pericarditis recurrence.

Methods and results: RHAPSODY was a Phase 3 double-blind, placebo-controlled, randomized-withdrawal trial that demonstrated the efficacy of rilonacept in recurrent pericarditis (RP). Patients with a history of multiple RP and an active recurrence were enrolled and had the option to participate in a cardiac magnetic resonance (CMR) imaging substudy. CMRs were interpreted by a blinded independent core laboratory with prespecified criteria to define pericardial LGE. Compared to patients with trace or mild pericardial LGE (n = 9), patients with moderate or severe pericardial LGE (n = 16) generally had a higher number of recurrent episodes per year (5.3 vs. 3.9) and a higher mean CRP level (3.6 vs. 1.1 mg/dL). Overall, 10/14 (71.4%) who received a placebo had a recurrence compared to 0/11 (0%) who received rilonacept. In patients randomized to placebo who had moderate or severe pericardial LGE, the median time to recurrence was 4.2 weeks compared to 10.7 weeks in patients who had trace or mild pericardial LGE. At the conclusion of the event-driven randomized-withdrawal period, among patients receiving a placebo, 5/7 (71.4%) with trace or mild pericardial LGE and 5/7 (71.4%) with moderate or severe pericardial LGE had a recurrence.

Conclusions: Among patients with multiple RP, these preliminary findings support the concept of pericardial LGE as an imaging biomarker that may inform the duration of treatment and risk of recurrence with cessation of therapy and larger studies should be considered.

Clinicaltrialsgov identifier: NCT03737110.