The U.S. Food and Drug Administration (FDA) has approved UCB's Bimzelx (bimekizumab-bkzx) for the treatment of adults with active psoriatic arthritis (PsA), active non-radiographic axial spondyloarthritis (nr-axSpA) with objective signs of inflammation, and active ankylosing spondylitis (AS). This approval marks a significant advancement in the treatment of these chronic inflammatory conditions, offering a novel approach by selectively inhibiting both interleukin 17A (IL-17A) and interleukin 17F (IL-17F).
Clinical Efficacy in Psoriatic Arthritis
The approval for psoriatic arthritis was supported by data from the Phase 3 BE OPTIMAL and BE COMPLETE studies. The BE OPTIMAL study involved biologic-naïve patients, while the BE COMPLETE study focused on patients with inadequate response or intolerance to TNF inhibitors (TNFi-IR). Key findings include:
- ACR50 Response: In both bDMARD-naive and TNFi-IR patients, approximately 44% of those receiving bimekizumab achieved an ACR50 response at Week 16, compared to 10% and 7% in the placebo groups, respectively (p<0.0001).
- Minimal Disease Activity (MDA): At Week 16, 45% and 44% of bimekizumab-treated patients in the bDMARD-naive and TNFi-IR groups, respectively, achieved MDA, versus 13% and 6% in the placebo groups (p<0.0001).
- Complete Skin Clearance (PASI100): Among patients with baseline psoriasis affecting ≥3% of body surface area, 47% and 59% in the bDMARD-naive and TNFi-IR groups, respectively, achieved complete skin clearance (PASI100) at Week 16, compared to 2% and 5% in the placebo groups.
These clinical responses were generally sustained to Week 52, demonstrating the long-term efficacy of bimekizumab in treating psoriatic arthritis.
Axial Spondyloarthritis Data
The approvals for nr-axSpA and AS were based on data from the Phase 3 BE MOBILE 1 and BE MOBILE 2 studies, respectively. Key results include:
- ASAS40 Response: In the nr-axSpA and AS populations, 47.7% and 44.8% of patients receiving bimekizumab achieved an ASAS40 response at Week 16, compared to 21.4% and 22.5% receiving placebo (p<0.001).
- Low Disease Activity: Low disease activity (ASDAS <2.1) was achieved at Week 16 by 46.2% of patients with nr-axSpA and 44.9% of patients with AS, versus 20.6% and 17.5% in the placebo groups.
These responses were also sustained to Week 52, with consistent outcomes across both TNFi-naïve and TNFi-inadequate responder populations. Furthermore, sustained reduction of objective inflammatory signs in both sacroiliac joints and the spine was observed via MRI at Weeks 16 and 52.
Dosing and Administration
The FDA recommends a dosage of 160 mg of bimekizumab administered via subcutaneous injection every four weeks for adult patients with active PsA, active nr-axSpA with objective signs of inflammation, and active AS. For PsA patients with co-existent moderate to severe plaque psoriasis, the dosage and administration are the same as for patients with moderate to severe plaque psoriasis.
Safety Profile
The most common adverse reactions (≥2%) in PsA patients include upper respiratory tract infections, oral candidiasis, headache, diarrhea, and urinary tract infection. In nr-axSpA, common adverse reactions include upper respiratory tract infections, oral candidiasis, headache, diarrhea, cough, fatigue, musculoskeletal pain, myalgia, tonsillitis, transaminase increase, and urinary tract infection. For AS, the most common adverse reactions include upper respiratory tract infections, oral candidiasis, headache, diarrhea, injection site pain, rash, and vulvovaginal mycotic infection.
Clinical Perspective
According to Joseph F. Merola, MD, MMSc, Professor, Dermatologist, Rheumatologist, and Investigator, BE OPTIMAL and BE COMPLETE, the consistent clinical response in patients who had a previous inadequate response to TNF inhibitors, and in patients who were new to biologics, suggests that bimekizumab has the potential to be an important new treatment option for adults with psoriatic arthritis.
Atul Deodhar, MD, Professor of Medicine and Medical Director of rheumatology clinics at Oregon Health & Science University, noted that the U.S. rheumatology community welcomes the approval of bimekizumab for use across the entire spectrum of axial spondyloarthritis, especially given the limited number of approved options currently available to treat both non-radiographic axial spondyloarthritis and ankylosing spondylitis.
With these approvals, bimekizumab offers a new, differentiated treatment option for rheumatology and dermatology communities, providing renewed hope for relief from the symptoms and health impacts of PsA and axSpA.
