UCB announced new three-year data from Phase 3 trials demonstrating that bimekizumab, a dual inhibitor of IL-17A and IL-17F, showed sustained control of inflammation and deep efficacy in patients living with psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA). The data were presented at EULAR 2025 in Barcelona, Spain.
Sustained Efficacy in Psoriatic Arthritis
In patients with active PsA, results from BE OPTIMAL, BE COMPLETE and their open-label extension, BE VITAL, showed that bimekizumab delivered sustained efficacy across multiple stringent clinical endpoints for up to three years. At three years, 59.5% and 59.1% of bDMARD-naïve and TNFi-IR patients, respectively, achieved elimination of swollen joints (SJC=0).
"A primary treatment goal in psoriatic arthritis is sustained control of inflammation to help prevent long-term, irreversible structural damage and to improve quality of life," said Professor Laure Gossec from the Sorbonne University Hospital, Paris, France. "These bimekizumab data are notable for their consistency across treatment-naïve and experienced patients, with elimination of swollen joints in nearly sixty percent of patients and approximately half reaching minimal disease activity (MDA) at three years – both strong clinical responses that suggest real control of inflammation in PsA."
Complete skin clearance, measured by Psoriasis Area and Severity Index (PASI)100 was maintained to three years by 61.9% and 67.5% of bDMARD-naïve and TNFi-IR patients, respectively. Minimal disease activity (MDA), a comprehensive and clinically meaningful endpoint, was sustained to three years by 52.9% and 48.8% of bDMARD-naïve and TNFi-IR patients, respectively.
Durable Responses in Axial Spondyloarthritis
Across patients with nr-axSpA and r-axSpA, data from two Phase 3 studies, BE MOBILE 1 and 2, and their combined open-label extension, BE MOVING, bimekizumab treatment demonstrated sustained clinical responses up to three years. Achievement of ASAS40 was sustained to three years by 60.4% and 60.1% of nr-axSpA and r-axSpA patients, respectively, while 61.8% and 59.9% of nr-axSpA and r-axSpA patients, respectively, maintained Axial Spondyloarthritis Disease Activity Score (ASDAS) low disease activity (LDA <2.1) through three years.
"Long-term data, showing that patients living with axSpA can maintain high levels of clinical response, are invaluable for informed treatment decisions. It's particularly compelling to see sustained responses with bimekizumab treatment at three years with stringent outcome measures like ASAS40 and low disease activity," said Professor Xenofon Baraliakos from the Rheumazentrum Ruhrgebiet Herne, Ruhr University Bochum, Bochum, Germany.
Comprehensive Safety Profile
A comprehensive safety analysis of bimekizumab demonstrated good long-term tolerability and consistent safety outcomes in patients with axSpA and PsA, according to pooled data from six integrated phase IIb/III clinical studies. The analysis encompassed 848 axSpA patients (2034.4 patient-years of exposure) and 1407 PsA patients (2590.8 patient-years) who received bimekizumab 160 mg every 4 weeks.
Treatment-emergent adverse events (TEAEs) occurred at comparable rates between the two populations, with exposure-adjusted incidence rates per 100 patient-years (EAIR/100 PY) of 136.9 and 139.6 for axSpA and PsA patients, respectively. Study discontinuation rates due to TEAEs remained low across both groups (2.7/100 PY in axSpA; 3.1/100 PY in PsA).
The most frequently reported adverse events included SARS-CoV-2 infection (axSpA: 7.8/100 PY; PsA: 8.8/100 PY), nasopharyngitis (axSpA: 8.2/100 PY; PsA: 7.7/100 PY), and upper respiratory tract infection (axSpA: 5.0/100 PY; PsA: 5.6/100 PY). Oral candidiasis occurred at rates of 3.7/100 PY in axSpA and 4.2/100 PY in PsA patients, with most cases being mild to moderate in severity.
Clinical Significance and Future Directions
"Psoriatic arthritis and axial spondyloarthritis are serious, chronic inflammatory diseases that can have a great impact in the daily lives of patients and their families. The data presented at EULAR reinforce the role of bimekizumab to deliver deep, consistent and sustained outcomes across a spectrum of PsA and axSpA," said Donatello Crocetta, Chief Medical Officer, UCB.
Bimekizumab is a humanized monoclonal IgG1 antibody that selectively inhibits both IL-17F and IL-17A, key pro-inflammatory cytokines involved in inflammation and new bone formation. Unlike IL-17A-specific inhibitors, bimekizumab targets and neutralizes IL-17F/F, IL-17A/A, and IL-17A/F, offering a broader approach to modulating the inflammatory response.
UCB presented 14 abstracts on PsA and axSpA at EULAR 2025, complementing other presentations in systemic lupus erythematosus and osteoporosis. These data, together with ongoing clinical research including the head-to-head Phase 3 BE BOLD trial in psoriatic arthritis, underscore UCB's commitment to advancing innovation in rheumatology.
