FDA Approves Bimekizumab for Three Rheumatologic Conditions

The US Food and Drug Administration has approved bimekizumab-bkzx (Bimzelx; UCB) for adult patients with active psoriatic arthritis (PsA), active nonradiographic axial spondyloarthritis (nr-axSpA) with objective signs of inflammation, and active ankylosing spondylitis (AS).

The drug, an interleukin (IL)-17A and IL-17F inhibitor, was first approved in October 2023 for treatment of moderate to severe plaque psoriasis in adults who are candidates for systemic therapy or phototherapy.

“In psoriatic arthritis and across the spectrum of axSpA, clinical study results and real-world experience outside the US have highlighted that Bimzelx can help patients achieve high thresholds of clinical response that are rapid in onset and sustained up to 2 years,” said Emmanuel Caeymaex, executive vice president, head of patient impact, and chief commercial officer of UCB in a press release. 

The recommended dosage of bimekizumab for adult patients with active PsA, nr-axSpA, or AS is 160 mg by subcutaneous injection every 4 weeks. For patients with PsA and coexistent moderate to severe plaque psoriasis, the dosage is the same as for patients with plaque psoriasis. The dosing for plaque psoriasis is to administer 320 mg (two 160-mg injections) by subcutaneous injection at weeks 0, 4, 8, 12, and 16, then every 8 weeks thereafter. For patients weighing ≥ 120 kg, consider a dose of 320 mg every 4 weeks after week 16.

PsA Clinical Trials

The approval for PsA was based on data from two phase 3 clinical trials, including 852 participants naive to biologics (BE OPTIMAL) and 400 participants with inadequate response to treatment with one or two tumor necrosis factor (TNF) inhibitors (BE COMPLETE). Both studies met their primary endpoint, 50% improvement in American College of Rheumatology 50 response criteria (ACR50) at 16 weeks, as well as ranked secondary endpoints. Secondary endpoints included minimal disease activity (MDA) and PASI 100 (complete skin clearance) at week 16.

At 16 weeks:

• About 44% of both the biologic-naive (189 of 431) and TNF inhibitor–resistant (116 of 267) groups receiving bimekizumab achieved ACR50 response, compared with 10% (28 of 281) and 7% (9 of 133) receiving placebo, respectively.
• About 45% of all patients treated with bimekizumab achieved MDA.
• Nearly 60% of TNF inhibitor–resistant patients had complete skin clearance.

These responses generally were sustained for 1 year. The most common adverse reactions are upper respiratory tract infections, oral candidiasis, headache, diarrhea, and urinary tract infection.

NR-axSpA and AS Clinical Trials

The approval for active nr-axSpA and active AS was based on data from two clinical studies, BE MOBILE 1 (nr-axSpA) and BE MOBILE 2 (AS). Both studies met their primary endpoint, 40% improvement in Assessment of SpondyloArthritis International Society response criteria (ASAS40) at 16 weeks.

Key findings included:

• In nr-axSpA patients, 47.7% (61 of 128) receiving bimekizumab achieved ASAS40 at week 16, compared with 21.4% (27 of 126) receiving placebo.
• In AS patients, 44.8% (99 of 221) in the bimekizumab group achieved ASAS40 response at week 16 vs 22.5% (25 of 111) receiving placebo.
• At 1 year in both groups, 60% treated with bimekizumab achieved an Ankylosing Spondylitis Disease Activity Score < 2.1.

In nr-axSpA, the most common adverse reactions are upper respiratory tract infections, oral candidiasis, headache, diarrhea, cough, fatigue, musculoskeletal pain, myalgia, tonsillitis, increase in transaminase, and urinary tract infection. In AS, the most common adverse reactions are upper respiratory tract infections, oral candidiasis, headache, diarrhea, injection-site pain, rash, and vulvovaginal mycotic infection.

Bimekizumab was approved by the European Commission for the same rheumatologic indications in June 2023.

Bimekizumab is currently available to eligible patients in the United States, according to the press release.