Bimekizumab shows promise across the spectrum of axial spondyloarthritis

The BE MOBILE 1*** and BE MOBILE 2*** cohorts consisted of 254 patients with active nr-axSpA (mean age 39.4 years, 54.3 percent male) and 332 patients with active AS (mean age 40.4 years, 73.2 percent male), respectively. Participants were randomized to receive either subcutaneous bimekizumab 160 mg Q4W (BE MOBILE 1: n=128; BE MOBILE 2: n=221) or placebo (BE MOBILE 1: n=126; BE MOBILE 2: n=111) for a 16-week double-blind period followed by a 36-week maintenance period. At week 16, all placebo recipients were switched over to bimekizumab 160 mg Q4W. [EULAR 2022, abstracts POS0939 and OP0019]

A significantly higher percentage of patients treated with bimekizumab achieved an ASAS40 response at week 16 compared with placebo in both the BE MOBILE 1 (47.7 percent vs 21.4 percent; p<0.001) and BE MOBILE 2 studies (44.8 percent vs 22.5 percent; p<0.001).

By week 24, the ASAS40 response rates were further increased to 52.3 percent (BE MOBILE 1) and 53.8 percent (BE MOBILE 2) among those initially assigned to bimekizumab.

An increase in ASAS40 response rates was also observed among those who were switched from placebo to bimekizumab in both studies (46.8 percent [BE MOBILE 1] and 56.8 percent [BE MOBILE 2]).

The benefit of bimekizumab was consistent regardless of prior exposure to tumour necrosis factor (TNF) inhibitors, with a higher ASAS40 response rate at week 16 observed with bimekizumab than with placebo across both TNFi-naïve (BE MOBILE 1: 46.6 percent vs 22.9 percent; BE MOBILE 2: 45.7 percent vs 23.4 percent) and TNFi-experienced subgroups (BE MOBILE 1: 60.0 percent vs 11.8 percent; BE MOBILE 2: 40.5 percent vs 17.6 percent).

In an exploratory analysis, more than half of the bimekizumab-treated patients who were initially randomized to bimekizumab achieved a low disease activity, as indicated by an ASDAS⁺ of <2.1, at week 24 in both studies.

Treatment-emergent adverse events occurred in 62.5 percent (BE MOBILE 1) and 54.3 percent (BE MOBILE 2) of the patients in the bimekizumab group and 56.2 percent (BE MOBILE 1) and 43.2 percent (BE MOBILE 2) in the placebo group.

Upper respiratory tract infection (17 events) and nasopharyngitis (21 events) were the most common AEs with bimekizumab in the BE MOBILE 1 and BE MOBILE 2 studies, respectively. No deaths or adjudicated major adverse cardiovascular events were reported in either treatment group in both studies.

Overall, both BE MOBILE 1 and BE MOBILE 2 studies met their primary and all secondary endpoints at week 16.

In both studies, the dual inhibition of IL-17F in addition to IL-17A with bimekizumab in patients with active nr-axSpA or AS resulted in rapid and clinically meaningful improvements of key signs and symptoms of disease and reduction of disease activity, said Dr Xenofon Baraliakos from Ruhr-University Bochum, Rheumazentrum Ruhrgebiet Herne, Bochum, Germany, who presented the BE MOBILE 1 study,  and Dr Désirée van der Heijde from the Leiden University Medical Center, Leiden, Netherlands, who presented the BE MOBILE 2 study.

The treatment effects of bimekizumab were very similar between the nr-axSpA and AS cohorts, van der Heijde highlighted.

“[Our] findings, in combination with the phase III results of bimekizumab in active AS, demonstrate the consistency of bimekizumab across the axSpA disease spectrum,” noted Baraliakos.

“The [overall] safety profile was consistent with prior studies, with no new new safety signals observed,” they added.

*ASAS40: Assessment of SpondyloArthritis International Society 40 percent response

**also known as radiographic axial spondyloarthritis (r-axSpA)

***BE MOBILE 1: A study to evaluate the efficacy and safety of bimekizumab in subjects with active nonradiographic axial spondyloarthritis; BE MOBILE 2: A study to evaluate the efficacy and safety of bimekizumab in subjects with active ankylosing spondylitis

⁺ASDAS: Ankylosing Spondylitis Disease Activity Score