Firsekibart as a Prophylactic Treatment for Acute Gout Flare in Participants Initiating Urate-Lowering Therapy: A Phase 2, Randomized, Open-Label, Multicenter, Active-Controlled Trial

Objective: To evaluate the efficacy and safety of firsekibart versus colchicine for prophylaxis against acute gout flares in participants initiating urate-lowering therapy (ULT). Methods: In this randomized, multicenter, open-label, active-controlled, phase 2 trial, participants were randomized (1:1:1) to receive a single subcutaneous injection of firsekibart 100 mg or 200 mg or oral colchicine 0.5 mg/day for 12 weeks. ULT was initiated at baseline or within 1 week before screening. The primary endpoint was the mean number of acute gout flares per participant over 12 weeks. Results: A total of 162 participants received firsekibart 100 mg (n = 55), 200 mg (n = 52), or colchicine (n = 55). Baseline characteristics were comparable between groups. No flares were observed in the firsekibart 200 mg group within 12 weeks. The adjusted mean number of acute gout flares per participant was 0.02 with firsekibart 100 mg and 0.34 with colchicine, with a rate ratio of 0.05 (95% confidence interval 0.01-0.43; P = 0.0060). Both treatment groups receiving firsekibart (at either dose) had a lower proportion of patients with at least one acute gout flare than the colchicine group. Firsekibart had a favorable safety profile, with no treatment-emergent adverse events (AEs) leading to treatment discontinuation/study withdrawal, no treatment-related serious AEs, and no deaths. Conclusion: Firsekibart provided superior prophylaxis against acute gout flares compared with colchicine in patients initiating ULT, with a favorable tolerability profile, supporting its potential as a treatment option for patients with gout initiating ULT.