Bimekizumab Clinical Efficacy Up to 2 Years Across Patients with Psoriatic Arthritis and Varying Baseline Joint Involvement: Results from a Post Hoc Analysis of 2 Pooled Phase 3 Studies

Objectives To assess bimekizumab (BKZ) efficacy in subgroups of patients with psoriatic arthritis (PsA) with varying baseline (BL) joint involvement over up to 2 years. Methods Post hoc analysis assessed subcutaneous BKZ 160mg every 4 weeks (wks; Q4W) in patients with PsA and varying BL joint involvement. Patients were grouped by BL swollen joint count (SJC) based on quartiles: SJC ≤5, 6-≤7, 8-≤12, >12. Due to few patients with BL SJC 3/4, patients with SJC 5 were included in first quartile; quartile sizes vary. Patients were pooled from BE OPTIMAL ( NCT03895203 ; biologic DMARD [bDMARD]-naïve) and BE COMPLETE ( NCT03896581 ; TNF inhibitor inadequate response/intolerance [TNFi-IR]). Unequal trial sizes (BE OPTIMAL 431 BKZ, 281 PBO; BE COMPLETE 267 BKZ, 133 PBO) yielded unequal quartile proportions. Both trials required ≥3 tender and swollen joints and had 16-wk double-blind, placebo (PBO)-controlled periods. Completers of BE OPTIMAL Wk52 or BE COMPLETE Wk16 could enter BE VITAL ( NCT04009499 ; open-label extension), with all patients receiving BKZ. BE OPTIMAL included a reference arm (adalimumab 40mg Q2W); data not reported due to small patient numbers in SJC quartiles. Outcomes reported: ACR ≥50% improvement, Psoriasis Area and Severity Index 100% improvement, minimal disease activity, SJC=0, Pain visual analog scale ≥50/70% improvement from BL, Health Assessment Questionnaire - Disability Index minimal clinically important difference (≥0.35 decrease from BL in patients with BL score ≥0.35). Data were pooled across trials and reported by randomization group at Wk16, Year 1 (Wk52), and Year 2 (Wk104/100 from BE OPTIMAL/BE COMPLETE). Results At BL, SJC distributions were: ≤5 (n=370), 6-≤7 (n=215), 8-≤12 (n=275), >12 (n=252). At Wk16, BKZ-treated patients demonstrated numerically greater improvements in joint, skin, composite, and patient-reported outcomes vs PBO, across patients with varying BL joint involvement. For all domains assessed, improvements were sustained to 2 years in BKZ-randomized patients, with robust efficacy across patients with varying BL joint involvement (Figure 1); (patient-reported outcome data not shown). For patients who switched from PBO to BKZ at Wk16, improvements in efficacy similar to BKZ-randomized patients with varying BL joint involvement were reported to Year 1 and sustained to Year 2. Figure 1. (A) ACR50, (B) PASI100, (C) MDA, and (D) SJC=0 responders at Week 16, Year 1, and Year 2, reported by baseline joint involvement (NRI, OC) Conclusion In patients with PsA and varying BL joint involvement, BKZ treatment demonstrated greater improvements vs PBO across disease domains at Wk16, and improvements were sustained to 2 years. Efficacy was robust across all groups of patients with varying BL joint involvement, reflecting the broader range of patients seen in clinical practice.