Background/Purpose: Bimekizumab (BKZ), a monoclonal IgG1 antibody that selectively inhibits interleukin (IL)‑17F in addition to IL‑17A, has demonstrated sustained efficacy to 3 years (yrs) in phase 3 clinical trials of patients (pts) with PsA, psoriasis, or axial spondyloarthritis (axSpA).1–4 The Group for Research and Assessment of Psoriasis and PsA (GRAPPA)‑based treatment recommendations focus on six core domains and the PsA‑related conditions‍ uveitis and IBD.5 Here, long-term BKZ efficacy is shown across GRAPPA domains up to 3 yrs, corresponding to an additional 1 yr of BKZ treatment, from phase 3 trials in PsA and axSpA.

Methods: Included pts were randomized to subcutaneous BKZ 160 mg or placebo (PBO) every 4 weeks (wks; Q4W) in BE OPTIMAL (NCT03895203; biologic DMARD [bDMARD]‑naïve pts with PsA), BE COMPLETE (NCT03896581; pts with PsA with inadequate response or intolerance to TNF inhibitors [TNFi‑IR]), BE MOBILE 1 (NCT03928704; non‑radiographic axSpA) and BE MOBILE 2 (NCT03928743; radiographic axSpA, i.e., AS). From Wk 16, all PBO-randomized pts received BKZ 160 mg Q4W. Wk 52/16 BE OPTIMAL/BE COMPLETE completers were eligible for BE VITAL open-label extension (OLE; NCT04009499); BE MOBILE 1 and 2 Wk 52 completers could enter BE MOVING (OLE; NCT04436640).Outcomes reported by GRAPPA domain (Table) to Yr 3 (Wk 160/156 BE OPTIMAL/BE COMPLETE) in PsA; uveitis and IBD reported to Wk 156 (BE OPTIMAL/BE COMPLETE). We report axial domain outcomes in axSpA to assess BKZ efficacy in axial disease, in accordance with GRAPPA recommendations,5 to Wk 164 (BE MOBILE 1/2). Missing data imputed using modified non‑responder and multiple imputation (mNRI; MI) for binary and continuous outcomes, and reported using observed case (OC).

Results: Wk 160/156/164 completion was similar across all trials (BE OPTIMAL: 546/712 [76.7%], BE COMPLETE: 299/400 [74.8%], BE MOBILE 1: 175/254 [68.9%], BE MOBILE 2: 247/332 [74.4%]). Baseline demographics and disease characteristics were previously reported.6–8For the majority of GRAPPA domains, 1-yr improvements were sustained to 3 yrs across all studies. Individual domain responses were consistent between bDMARD‑naïve and TNFi-IR pts (Figure). Improvements in axial outcomes were sustained to 3 yrs in BE MOBILE 1 and 2 (Table, Figure). Exposure-adjusted incidence rates per 100 pt-yrs for uveitis and definite or probable adjudicated IBD to Wk 156 were 0.2 (95% confidence interval 0.1, 0.6) and 0.3 (0.1, 0.7) in BE OPTIMAL and 0 and 0.1 (0.0, 0.6) in BE COMPLETE, respectively.

Conclusion: BKZ treatment resulted in sustained and consistent improvements across GRAPPA domains from 1 to 3 yrs in both bDMARD‑naïve and TNFi‑IR pts with PsA, with low rates of IBD and uveitis reported. Results from studies in pts across the full disease spectrum of axSpA further support BKZ efficacy in the axial domain and suggest BKZ efficacy for axial disease in PsA.8 References: 1. Gossec L. Ann Rheum Dis 2025:In press; 2. McInnes IB. Ann Rheum Dis 2025:In press; 3. Warren RB. Br J Dermatol 2025;00:1–12; 4. Baraliakos X. Ann Rheum Dis 2025:In press; 5. Coates LC. Nat Rev Rheumatol 2022;18:465–79; 6. Ritchlin CT. Ann Rheum Dis 2023;82:1404–14; 7. Coates LC. RMD Open 2024;10:e003855; 8. van der Heijde D. Ann Rheum Dis 2023;82:515–26.

Table. Efficacy outcomes at baseline, Year 1, and Year 3 from BE OPTIMAL, BE COMPLETE, and both BE MOBILE 1 and BE MOBILE 2 by GRAPPA domain (mNRI, NRI, MI, OC)

Figure. GRAPPA individual domain response and change from baseline at Year 1 and Year 3 from BE OPTIMAL, BE COMPLETE, and pooled BE MOBILE 1 and BE MOBILE 2 (MI, mNRI, NRI, OC)

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/sustained-efficacy-up-to-3-years-with-bimekizumab-treatment-across-grappa-core-domains-in-patients-with-psoriatic-arthritis-long-term-results-from-two-phase-3-trials/