Salvage treatment of AOSD-associated macrophage activation syndrome with bariticinib following conventional immunosuppressive therapy.

Abstract

Objectives: Adult-onset Still's disease (AOSD)-associated macrophage activation syndrome (MAS) is a highly inflammatory condition. Currently, the main treatment method for AOSD-associated MAS is high-dose glucocorticoid shock therapy, but the effect is not satisfactory, and new therapeutic methods or drugs are urgently needed. The aim of this study was to evaluate the efficacy and safety of salvage baricitinib therapy for AOSD-associated MAS following conventional immunosuppressive therapy.

Method: Data from nine patients with MAS treated in the Department of Infection and the Department of Rheumatology, First Affiliated Hospital of Soochow University, from January 2020 to December 2022, were retrospective analysed. Salvage therapy with baricitinib was administered, with an initial dose of 8 mg/day. The patients' clinical symptoms and MAS indices (blood counts and triglyceride, fibrinogen, lactate dehydrogenase, sCD25, and Fer levels) were observed. After a complete response was achieved, the baricitinib dose was gradually reduced to 2-4 mg/day and maintained.

Results: The MAS blood test results of all nine patients improved to varying degrees within 1 week post-treatment. The MAS indices gradually returned to normal approximately 8 weeks after discharge; at the 12-month outpatient follow-up, seven patients did not develop MAS again, but two patients (patients 5 and 9) had MAS recurrence. The follow-up period ended with salvage treatment with emapalumab.

Conclusions: Baricitinib can effectively inhibit the inflammatory response and improve outcomes in the treatment of MAS secondary to rheumatic immunity-related diseases; moreover, this drug treatment is safe. Our study provides a new strategy for MAS salvage therapy. Key Points • Bariticinib may be a palliative treatment option for recurrent/refractory MAS.