Anakinra for recurrent pericarditis: a retrospective evaluation of long-term effectiveness, initiation timing and tapering.

IL-1 antagonists have emerged as an effective treatment for refractory or GC-dependent recurrent pericarditis (RP). This study aims to describe long-term efficacy and safety of anakinra in anakinra-treated RP patients and retrospectively explore the effect of early anakinra initiation and the risk of recurrence upon tapering. This is a retrospective study, based on medical records. The main outcome was any recurrence ("flare") after anakinra initiation. Twenty patients (14 males, 6 females) were included with a median (IQR) disease duration of 48 (24) months, and 4 (2) recurrences prior to anakinra initiation. The median (IQR) age at pericarditis onset was 50 (31) years. Sixteen were on GC (mean (SD) prednisolone dose 17.7 (12.3) mg). Anakinra was initiated after a median (IQR) time of 11.5 (11.5) months from the first episode of acute pericarditis. Nineteen achieved remission on anakinra. Twelve achieved GC withdrawal while 4 remained on low-dose prednisolone (mean [SD] dose 3 mg [1]). Nine patients proceeded to tapering of anakinra after a median (IQR) of 8 (16) months on standard dosage and 7 patients remained on extended-interval administration at the end of the follow-up period. Flares occurred in 3/9 patients with a history of ≤ 3 pericarditis recurrences before anakinra initiation versus 4/11 with > 3 recurrences [exploratory univariable OR 1.14, (CI 0.13-11.13)] and in 2/5 patients treated early (< 6 months following diagnosis) versus 5/15 in the late-treated group (≥ 6 months) [exploratory univariable OR 0.76 (CI 0.06-11.94)]. Annualized recurrence rates were lower after anakinra initiation [median (IQR) recurrences 0 (0.26) versus 5.33 (4.68)]. In exploratory logistic regression analyses, neither early/late anakinra initiation, number of pre-anakinra recurrences, nor tapering was significantly associated with the outcome. The analyses' findings should be interpreted with caution, given the limited sample size, the wide confidence intervals and the potential lack of statistical power to detect existing associations. In this cohort of RP patients, anakinra was associated with favorable clinical outcomes, allowing for GC sparing and achieving lower recurrence rates after initiation compared with the pre-treatment period. The sustained disease control observed supports its long-term use, either at full dose or with careful tapering. Exploratory comparisons for potential existing associations with flares were limited by small sample size. To determine the ideal treatment duration and tapering strategies, larger prospective controlled studies are required.