Intravenous anakinra for the treatment of haemophagocytic lymphohistiocytosis/macrophage activation syndrome: A systematic review.

BACKGROUND: Haemophagocytic lymphohistiocytosis (HLH) or macrophage activation syndrome (MAS) has a potentially high mortality rate. Anakinra, an interleukin-1 receptor antagonist, is now recommended early in HLH/MAS, with intravenous (IV) use proposed in critically unwell patients. This systematic review establishes the literature relating to IV anakinra in secondary HLH/MAS (sHLH/MAS). METHODS: We screened Embase, PubMed, and Medline, including all reports of IV anakinra for HLH or MAS. We extracted age, HLH/MAS trigger, continuous infusion or bolus dosing, and survival. RESULTS: Twenty-nine case reports/series identified 87 patients (median age 22 years, range 22 months to 84 years), all with sHLH. Amongst identifiable triggers, 43% were systemic infection, 33% rheumatological, 9% oncological. Children had predominantly a rheumatological trigger (48%), whilst adults were more commonly infection-driven (50%). Overall, rheumatologically triggered disease showed greater survival (83.3%), particularly compared with oncological triggers (42.9%). Children had a greater survival, particularly under 10 years (83%, vs. adults, 63%). CONCLUSIONS: Despite IV anakinra recipients likely to be critically unwell, this cohort had similar disease triggers and survival compared to large historical cohorts, and enhances awareness of age and trigger-specific survival patterns. IV anakinra had a wide therapeutic dosing range and tolerability, regardless of trigger, demonstrating substantial utility in severe sHLH/MAS.