Bimekizumab Demonstrated Early and Sustained Efficacy Regardless of Baseline Characteristics in Patients with Active Psoriatic Arthritis: Pooled Post Hoc Results Up to 1-Year from Two Phase 3 Studies

Objectives To assess the impact of baseline (BL) characteristics on bimekizumab (BKZ) efficacy in patients with psoriatic arthritis (PsA) at Week (Wk)16 vs placebo (PBO) and through 1 year. Methods Pooled post hoc analysis was conducted for data from BE OPTIMAL ( NCT03895203 ; biologic DMARD [bDMARD]-naïve) and BE COMPLETE ( NCT03896581 ; TNF inhibitor inadequate response/intolerance [TNFi-IR]). Both studies assessed subcutaneous BKZ 160 mg every 4 wks in patients with PsA and were PBO-controlled to Wk16, then PBO patients switched to BKZ (PBO/BKZ). BE COMPLETE Wk16 completers could enter BE VITAL ( NCT04009499 ; open-label extension), in which all patients received BKZ. Efficacy outcomes are reported by BL patient characteristic subgroups. Efficacy outcomes included ≥50% improvement from BL in ACR response criteria (ACR50), the composite outcome minimal disease activity (MDA), complete resolution of swollen joint count (SJC=0), and 100% improvement from BL in Psoriasis Area and Severity Index (PASI100; in patients with BL psoriasis ≥3% body surface area). Data are reported by randomization group at Wk16; for the BKZ Total group (PBO/BKZ and BKZ-randomized) at Wk52. The association of BKZ-treated vs PBO patients achieving Wk16 response overall and for each subgroup was estimated via odds ratios using logistic regression with factors for treatment, study, region, subgroup, and treatment by subgroup interaction (subgroup and interaction excluded in the overall). All p values are nominal and generated for the treatment by subgroup interaction term; missing data used non-responder imputation. Results Of the 1,112 patients randomized to PBO (n=414) or BKZ (n=698), 1,073 (96.5%) completed Wk16 and 1,002 (90.1%) completed Wk52. Overall BL demographics and disease characteristics were generally similar between treatment groups. Achievement of ACR50, MDA, SJC=0, and PASI100 responses were greater with BKZ vs PBO within all patient subgroups at Wk16, with consistent efficacy responses with BKZ treatment for most patient subgroups. Younger patients (<45 years) treated with BKZ were significantly more likely than older patients (≥45 years) to achieve ACR50 (p=0.001), MDA (p=0.006), and SJC=0 (p=0.035) at Wk16. Males were significantly more likely than females to attain ACR50 (p<0.001). Improved efficacy responses with BKZ treatment were sustained or increased from Wk16 to Wk52 across all subgroups (Figure 1); (SJC=0 and PASI100 data not shown). Figure 1. ACR50 and MDA response rates at Week 16 and Week 52 by baselines demographics and disease characteristics (NRI) Conclusion BKZ demonstrated durable and greater improvements in clinical joint, skin, and composite outcomes measures vs PBO at Wk16, which were sustained to 1 year, regardless of patient demographics and clinical presentation at BL.