Abstract
Objective To evaluate long-term safety and efficacy of dazukibart, a novel anti-interferon beta monoclonal antibody, in adults with moderate-to-severe dermatomyositis (DM).
Methods Participants from two cohorts of DM (skin-predominant, SP and muscle-predominant, MP), completing a 24-week phase 2, double-blind study, were enrolled into a 52-week phase 2b, open-label extension (OLE) study, with a 16-week follow-up post treatment (combined study: 92 weeks). Pooled skin-analysis set included all SP and MP DM (with baseline CDASI-A [Cutaneous Dermatomyositis Disease Area and Severity Index-Activity]≥ 14) participants. Primary endpoint was incidence of treatment-emergent adverse events (TEAEs; weeks 24-92). Key secondary endpoints were change in CDASI-A and Total Improvement Score (TIS) (weeks 0-92).
Results Participants who received ≥ 1 dose of dazukibart (600 mg) during the OLE study (n = 9 [SP], 15[MP], 16[pooled skin-analysis set]) were analyzed (median age- 49.5 years; 83% females; 96% White). Treatment-related TEAEs were mild (55%), moderate (38%), or severe (7%), with no treatment-related serious adverse events or treatment discontinuations. At week 76, CDASI-A scores improved, with median change from baseline of −24.0 (range −33 to −12; SP), −9.0 (range −32 to 1; MP), and −23.5 (range −33 to −12; pooled skin-analysis set). In the MP cohort, TIS (65.0 [range 2.5 to 9.5]) and associated core set measures (including patient-reported outcomes) improved at week 76. Overall, the observed improvements (slight reduction) in outcomes persisted during the 16-week post-treatment follow-up.
Conclusion The safety and efficacy profiles of dazukibart observed at 24 weeks were sustained through 92 weeks.
