Inebilizumab treatment in Japanese patients with IgG4-related disease: A subgroup analysis of a randomized, double-blind, placebo-controlled, phase 3 trial (MITIGATE).

Abstract

Objectives: This subgroup analysis of the MITIGATE study aimed to evaluate whether the efficacy and safety of inebilizumab in Japanese patients with IgG4-related disease are consistent with those observed in the overall trial population.

Methods: MITIGATE was a randomized, double-blind, placebo-controlled, phase 3 study conducted in 22 countries, and this subgroup analysis included the Japanese patients enrolled in that trial.

Results: In total, 27 Japanese patients (inebilizumab, N = 20; placebo, N = 7) were included in this subgroup analysis. The organs most frequently affected were the submandibular gland (66.7%), lacrimal gland (59.3%), and pancreas (51.9%). Despite the discontinuation of glucocorticoids within 8 weeks of study initiation, there were no adjudication committee-determined flares requiring treatment in the inebilizumab group. Flares were observed in four patients (57.1%) in the placebo group, with a median time to the first flare of 246.0 days. Inebilizumab reduced the annualized flare rate, increased flare-free complete remission, and lowered glucocorticoid use. Safety profiles were similar between treatment groups; most treatment-emergent adverse events were non-serious.

Conclusions: Inebilizumab reduced flare risk and glucocorticoid exposure, and it was well tolerated in Japanese patients with IgG4-related disease, which is consistent with the overall MITIGATE results.

Trial registration: NCT04540497.