The open-label extension of the BE-MOBILE studies has shown that bimekizumab delivers long-term safety and efficacy in patients with axial spondyloarthritis.

The study, published in The Journal of Rheumatology [link here], adds to the growing evidence for the dual IL-17A and IL-17F inhibitor across the full disease spectrum of axSpA and other immune-mediated inflammatory diseases.

As reported recently in the limbic [link here], bimekizumab has also demonstrated sustained high levels of efficacy and tolerability out to 3 years in patients with psoriatic arthritis.

The BE-MOBILE 1 and 2 studies enrolled patients with non-radiographic and radiographic axSpA respectively into bimekizumab or placebo treatment arms for 16‑weeks followed by a 36-week active-treatment maintenance period.

Early RCT results were published in 2023 [link here] and 2-year results from the open-label extension in which all patients received bimekizumab were published in 2025 [link here].

Now, after the 52-week RCTs and 112-week extension, it reports that bimekizumab demonstrated sustained clinical efficacy and inflammation control over 3 years.

Improvements observed between baseline and week 104 were generally sustained to week 164 across disease activity, physical function, spinal mobility, spinal pain, morning stiffness, fatigue and HRQoL outcomes, it said.

“This pattern of improvement was observed consistently across patients with nr-axSpA and r-axSpA.”

Among efficacy outcomes at week 164:

• ASDAS low disease activity was achieved by 57% of patients and ASDAS inactive disease by 28.7%
• 52.2% of patients with baseline enthesitis (MASES >0) achieved total resolution of enthesitis
• 59.7% of patients with baseline swollen joint count >0 achieved total resolution of peripheral arthritis
• 59.4% of patients with nr-axSpA and baseline SPARCC score of the SIJ ≥2 achieved MRI remission
• 77.8% of patients with r-axSpA and baseline MRI Berlin spine score >2 achieved MRI remission.

Regarding overall safety, the most frequently reported TEAEs were COVID-19 (34.0%), nasopharyngitis (24.2%), upper respiratory tract infection (15.3%), oral candidiasis (11.5%) and diarrhoea (8.5%).

Serious TEAEs affected 13.2% of patients and 7.3% had TEAEs leading to treatment discontinuation. No deaths were reported over 3 years.

In pre-specified safety topics of interest, no major adverse cardiovascular events or active tuberculosis were reported following 3 years of bimekizumab exposure. Rates of neutropenia and malignancies were also low and the majority of fungal infections were mild to moderate mucocutaneous infections such as oral candidiasis.

“No new safety signals were observed over 3 years of bimekizumab treatment, in line with previous observations on the long-term safety profile of bimekizumab from the phase 2b BE AGILE trial and its OLE in r-axSpA, as well as other phase 3 trials in psoriatic arthritis, psoriasis and hidradenitis suppurativa,” it said.

The investigators concluded that bimekizumab was a durable long-term treatment option for patients with nr-axSpA and r-axSpA with a positive benefit-risk profile.