P181 Long-term safety and tolerability of bimekizumab treatment across phase 2b and phase 3 studies in patients with axial spondyloarthritis or psoriatic arthritis: 3-year update from the phase 3 studies

Abstract Background/Aims Previous analyses of phase (Ph)2b/3 safety data (data cut-off: July 2023) demonstrated bimekizumab (BKZ) was generally well tolerated in patients with axial spondyloarthritis (axSpA; exposure: 2,513.8 patient-years PY) or psoriatic arthritis (PsA; exposure: 3,655.9PY) long-term (∼2 years). Here, updated safety analyses, including a 3rd year of BKZ exposure from ongoing Ph3 open-label extensions (OLEs), are presented. Methods Safety data reported for two pools, comprising one Ph2b and two Ph3 studies and OLEs, in axSpA (non-radiographic and radiographic) and PsA patients, respectively. Exposure-adjusted incidence rates (EAIR)/100PY and n (%) are reported for treatment-emergent adverse events (TEAEs; classified using MedDRA v19.0) among patients who received ≥1 dose BKZ 160 mg every four weeks (Q4W) in any treatment period. Data reported to data-cuts of September 2024 (axSpA)/August 2024 (PsA) in BE MOVING and BE VITAL OLEs (corresponding with ≥156 weeks total Ph3 study participation). Results AxSpA and PsA safety pools included 848 (2,748.9PY) and 1,409 patients (4264.7PY), respectively. Comparison of safety data with previous analyses did not indicate increase in EAIRs of the majority of TEAEs; some TEAEs EAIRs decreased with longer BKZ exposure, including Candida infections. Most frequent TEAEs were SARS-CoV-2 (COVID-19) infection, nasopharyngitis and upper respiratory tract infection (Table). Safety topics of interest are reported (Table). EAIR/100PY of serious infections: 1.4 (axSpA), 1.2 (PsA). EAIR/100PY of fungal infections: 8.1 (axSpA), 7.1 (PsA). Most fungal infections were mucocutaneous and mild/moderate in severity; oral candidiasis was most common. Permanent BKZ discontinuation due to oral candidiasis was infrequent (axSpA: 0.2/100PY; PsA: 0.3/100PY). No systemic fungal infections reported. No active tuberculosis, histoplasmosis, coccidioidomycosis or blastomycosis reported. EAIR/100PY of hepatic events: 4.9 (axSpA), 4.6 (PsA); most were transient liver enzyme abnormalities (Table; no confirmed cases of Hy’s law). EAIR/100PY for adjudicated definite/probable IBD: 0.7 (axSpA), 0.2 (PsA). EAIR/100PY for uveitis: 1.2 (axSpA), 0.1 (PsA). Suicidal ideation/behaviour rates were low; no cases of completed suicide (Table). Other safety topics of interest rates shown in the Table. No additional deaths since previous data-cut (Table). Conclusion With an additional year of exposure, BKZ’s long-term safety in axSpA and PsA remained consistent with prior analyses; no new safety signals/concerns. Disclosure P.J. Mease: Consultancies; AbbVie, Acelyrin, Amgen, BMS, Century, Cullinan, Eli Lilly, Inmagene, Johnson AbbVie, Amgen, Eli Lilly, Johnson AbbVie, Acelyrin, Amgen, BMS, Eli Lilly, Johnson AbbVie, Biocad, Eli Lilly, Gilead, GSK, MSD, MoonLake Immunotherapeutics, Novartis, Pfizer, Samsung Bioepis, UCB. Member of speakers’ bureau; AbbVie, BMS, Eli Lilly, MSD, Novartis, Pfizer, UCB. Grants/research support; AbbVie, Eli Lilly, MSD, Novartis, Pfizer. R. Bajracharya: Shareholder/stock ownership; UCB. Other; Employee of UCB. B. Ink: Shareholder/stock ownership; AbbVie, GSK, UCB. Other; Employee of UCB. M. Manente: Shareholder/stock ownership; UCB. Other; Employee of UCB. L. Peterson: Shareholder/stock ownership; UCB. Other; Employee of UCB. K. White: Shareholder/stock ownership; UCB. Other; Employee of UCB. P. Nash: Consultancies; AbbVie, AstraZeneca, BMS, Janssen, Lilly, Novartis, Pfizer, Servatus, UCB, Xencor. Member of speakers’ bureau; AbbVie, AstraZeneca, BMS, Janssen, Lilly, Novartis, Pfizer, UCB. Grants/research support; AbbVie, Amgen, AstraZeneca, BMS, Janssen, Eli Lilly, Novartis, Pfizer, Servatus, UCB, Xencor. L.S. Gensler: Consultancies; Acelyrin, Eli Lilly, Janssen, Novartis, Pfizer, UCB. Grants/research support; UCB (paid to institution).