medwireNews: The monoclonal immunoglobulin G1 antibody bimekizumab is both well tolerated and efficacious in individuals with axial spondyloarthritis (axSpA) for up to 2 years after initiation, show results from the open-label extension (OLE) of the 12-month BE MOBILE 1 and 2 trials.
Rates of treatment-emergent adverse events (TEAEs) after 104 weeks of subcutaneous bimekizumab 160 mg given every 4 weeks for non-radiographic (nr)-axSpA and r-axSpA were similar to, or lower than, those reported after 52 weeks, report Xenofon Baraliakos, from Ruhr-University Bochum in Germany, and colleagues.
A similar trend emerged for rates of infection, including serious (eg, appendicitis) and non-serious (eg, fungal) events, plus efficacy outcomes including the proportion of patients who met the Assessment of SpondyloArthritis International Society 40% (ASAS40) criteria, and the number who had a low disease activity status after bimekizumab treatment.
“Patients with nr-axSpA and r-axSpA share similar clinical presentations and disease burden, facing significant impacts on physical functioning and health-related quality of life […] due to chronic inflammatory back pain, stiffness and extra-articular manifestations, including enthesitis and peripheral arthritis,” write Baraliakos et al in Rheumatology.
The team investigated whether the previously demonstrated safety and efficacy profile of bimekizumab in BE MOBILE 1 and 2 would extend to 2 years in the 456 individuals with nr-axSpA (n=189) and r-axSpA (n=267) who joined the OLE.
Bimekizumab inhibits the cytokines interleukin (IL)-17A and IL-17F that are both overexpressed in axSpA pathology, explain the researchers, whereas earlier IL-17 inhibitors (eg, secukinumab and ixekizumab) have only targeted IL-17A.
The current findings show that individuals experienced comparable rates of TEAEs in weeks 52–104 of bimekizumab treatment as they did in weeks 0–52, at 70.8% and 78.6%, respectively. Rates for severe TEAEs were also better in the OLE phase than the primary phase (3.1 vs 4.3%), as were rates of serious TEAEs (5.4 vs 5.6%) and TEAEs leading to discontinuation (1.5 vs 4.2%), and there were no deaths during either period.
The most common TEAEs included SARS-CoV-2 infection, reported by 6.1% of participants over weeks 0–52 and 20.8% over weeks 52–104, with the second year of the study coinciding with the COVID-19 pandemic.
In addition, there were comparable or better rates of nasopharyngitis during weeks 52–104 than during weeks 0–52 (9.7 vs 10.6%), and this was also true for oral candidiasis (4.8 vs 7.3%), upper respiratory tract infection (4.6 vs 8.2%), headache (2.5 vs 5.7%), and diarrhea (1.7 vs 5.2%).
After 104 weeks of bimekizumab treatment, over half (51.9%) of individuals had achieved ASAS40 – defined as an improvement of at least 40% in at least three of the four axSpA domains of spinal pain, inflammation, patient global assessment, and function – as had 59.2% of participants in the initial BE MOBILE studies.
Overall, 98.8% of participants had high or very high Axial Spondyloarthritis Disease Activity scores (ASDAS) of at least 2.1 points at baseline. The key recommended treatment target for axSpA, a low ASDAS activity score (<2.1 points), was achieved by 59.3% of individuals at week 52 and 62.5% at week 104, while ASDAS inactive disease status (<1.3 points) was achieved by 27.2% and 31.5%, respectively.
“These results add to previous reports of rapid improvements in clinical efficacy outcomes to Week 16 with bimekizumab and sustained efficacy from Week 16 through 1 year,” write Baraliakos and co-authors.
In addition, 47.8% of patients with a Maastricht Ankylosing Spondylitis Enthesitis score above 0 points at baseline had a total resolution of enthesitis by week 104 of treatment. And the majority of patients had sustained magnetic resonance imaging (MRI) remission at week 104 – including 57.1% of nr-axSpa patients assessed using the MRI Spondyloarthritis Research Consortium of Canada sacroiliac joint score and 64.9% of r-axSpA patients assessed with the MRI Berlin spine score.
“[B]imekizumab treatment demonstrated a favourable long-term safety profile over 2 years,” remark the researchers.
They conclude: “The consistent safety profile and long-term maintenance of clinical response provide robust evidence supporting bimekizumab as an important treatment option for patients with axSpA.”
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