Bimekizumab Meets Primary and Secondary Endpoints for Treating Axial Spondyloarthritis

Today, UCB announced that they achieved all primary and ranked secondary endpoints from the Phase 3 BE MOBILE 1 study, which evaluated safety and efficacy of the dual interleukin 17A (IL-17A) and IL-17F inhibitor, bimekizumab, in adult patients with non-radiographic axial spondyloarthritis (nr-axSpA).

“Today’s positive findings from the Phase 3 BE MOBILE 1 study provide clear evidence supporting bimekizumab in the treatment of nr-axSpA, and suggest that targeting IL-17F in addition to IL-17A may be a promising treatment approach for this painful, chronic rheumatic condition that often starts in young adulthood,” Stated Atul Deodhar, MD, MRCP. Deodhar is Professor of Medicine, Division of Arthritis and Rheumatic Diseases, at Oregon Health and Science University.

The Study

BE MOBILE 1, a randomized, multicenter, double-blind, placebo-controlled, clinical trial, is the first study to determine safety and efficacy of bimekizumab in this patient population. It is the second Phase 3 study UCB conducted to analyze the drug across the axial spondyloarthritis spectrum. The first study, which focused on ankylosing spondylitis, also supported the clinical potential of bimekizumab to improve patient outcomes for those with axSpA.

Eligible patients met Assessment of SpondyloArthritis International Society (ASAS) classification criteria, had no radiographic sacroiliitis, and experienced inflammatory back pain for 3 or more months. Inflammation was determined via magnetic resonance imaging (MRI) and/or an elevated C-reactive protein (CRP).

Primary Endpoint

The primary endpoint was a significant and clinically meaningful improvement in the percentage of patients who attained the Assessment of SpondyloArthritis International Society 40 (ASAS40) by week 16 when compared with those receiving placebo. ASAS40 assesses physical function, spinal pain, inflammation, and disease activity.

Secondary Endpoints

Other endpoints included improvements in the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), which measured signs and symptoms of nr-axSpA, ASAS partial remission (PR), the nocturnal spinal pain score, and Ankylosing Spondylitis Disease Activity Score (ASDAS) Major Improvement (MI).

Safety

No new safety concerns were reported, and results were consistent with previous safety data.

The 52-week study is ongoing. Bimekizumab is not yet approved for treating nr-axSpA or ankylosing spondylitis. UCB plans to submit regulatory applications for the drug in axSpA in both the United States and European Union later in 2022.

About AxSpA

AxSpA affects the spine and joints surrounding the pelvis and lower spine, which results in fatigue, stiffness, and back pain that often improves with exercise, but not with rest. Other symptoms may include enthesitis, dactylitis, peripheral arthritis, psoriasis, acute anterior uveitis, and inflammatory bowel disease. Roughly half of patients with axSpA have nr-axSpA, defined as the absence of structural damage to the sacroiliac joints. While axSpA is more commonly diagnosed in men, nr-axSpA is seen more frequently in women.