A novel therapy for an unusual problem: IL-1 receptor antagonist for recurrent post-transplant pericarditis

Novel Pharmacotherapies for Recurrent Pericarditis: Current Options in 2020

Abstract

Recent advances have shown impressive results by anti-interleukin 1 (IL-1) agents in refractory idiopathic recurrent pericarditis.

Purpose of Review

We critically discuss the current state of the art of therapy of relapsing pericarditis, with a focus on new pharmacological approaches and on specific clinical settings such as pregnancy, pediatric patients, and secondary forms of relapsing pericarditis.

Recent Findings

Antagonism of the IL-1 is highly effective in idiopathic recurrent pericarditis with autoinflammatory features. Currently, available anti-IL-1 agents are anakinra and canakinumab. Rilonacept is another IL-1 antagonist, currently studied in the phase-3 clinical trial RHAPSODY. Available data suggest similar efficacy and safety profiles of these three agents, although only anakinra has been tested in randomized clinical trials. These agents have slightly different pharmacological properties, being canakinumab a specific IL-1ß antagonist while anakinra and rilonacept are unselective IL-1α and IL-1ß blockers. To date, there is no evidence that specificity against IL-1ß affects safety and efficacy in patients with relapsing pericarditis, although it has been proposed that unspecific blockage might be useful in severe disease.

Summary

Anakinra is the first anti-IL-1 agent with well-documented efficacy and safety in adult and pediatric patients with idiopathic relapsing pericarditis. Other anti-IL-1 agents are currently under study. Future research should clarify the optimal duration of therapy and tapering schedule of treatment with these agents. Moreover, biomarkers would be required to understand which patients will benefit from early administration of IL-1 blockers due to refractoriness to conventional therapy and which others will suffer from recurrences during the tapering of these agents. Lastly, future studies should focus on the subjects with the autoimmune or the pauci-inflammatory phenotype of idiopathic refractory pericarditis.

The autoinflammatory side of recurrent pericarditis: Enlightening the pathogenesis for a more rational treatment

Recurrent pericarditis (RP) is a troublesome and debilitating complication of acute pericarditis. Although the etiopathogenesis of this condition remains unknown, an intricate overlap of autoimmune and autoinflammatory pathways has been hypothesized to explain its beginning and recurrence over time. The majority of cases are defined as "idiopathic", reflecting our awkwardness to unravel the intimate mechanisms of RP. Given the possible occurrence of anti-nuclear, anti-heart and anti-intercalated disk antibodies as well as the association with peculiar human leukocyte antigen haplotypes, an autoimmune contribution has been claimed to specify the nature of RP. However, the most innovative pathogenic scenario of RP has been conferred to the innate immune system, mainly involving neutrophils and macrophages that produce a large amount of interleukin (IL)-1 via inflammasome activation. The clinical resemblance of RP with autoinflammatory diseases that may be marked by symptomatic serositis, high fevers and strikingly increased inflammatory parameters further suggests a similar inflammasome-mediated pathogenesis. Aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) remain the mainstay of therapy in RP, whereas colchicine is recommended on top of standard anti-inflammatory therapy, due to its role in inhibiting the IL-1 converting enzyme (caspase 1) within the inflammasome as well as the release of additional pro-inflammatory mediators and reactive oxygen species. With regard to treatment of RP refractory to NSAIDs and colchicine, blockade of IL-1 is the most relevant advance achieved in the last decade: the outstanding effect of the short-acting IL-1 receptor antagonist anakinra has been first recognized in the pediatric population, giving a proof of its practical feasibility. Over a more recent time, a growing experience with anakinra deriving from both large and small studies has further confirmed that RP might be regarded as an IL-1-mediated disease. This review aims to provide a contemporary insight into the mechanisms leading to RP as well as into the most recent literature data showing the beneficial approach originating from IL-1 blockade in this intriguing disorder.