Long-Term Safety with Bimekizumab in axSpA and PsA

An integrated, pooled long-term safety analysis of bimekizumab 160 mg every 4 weeks is reported in adults with axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA), using a July 2023 data cut from six phase IIb/III clinical studies. The report describes 848 patients with axSpA contributing 2513.8 patient-years of exposure and 1409 patients with PsA contributing 3655.9 patient-years. Safety outcomes are summarized as exposure-adjusted incidence rates per 100 patient-years (EAIR/100 PY).

The study reports overall treatment-emergent adverse event (TEAE) incidence (EAIR/100 PY) of 129.6 in axSpA and 126.9 in PsA, with TEAE EAIRs described as similar between indications. The most frequently reported TEAEs were SARS-CoV-2 (COVID-19) infection (EAIR/100 PY 9.9 in axSpA and 9.9 in PsA), nasopharyngitis (8.4 in axSpA and 6.8 in PsA), and upper respiratory tract infection (5.0 in axSpA and 5.7 in PsA). Discontinuations due to TEAEs are described as infrequent (EAIR/100 PY 2.4 in axSpA and 2.9 in PsA).

These same events—SARS-CoV-2 (COVID-19) infection, nasopharyngitis, and upper respiratory tract infection—are also listed among the most frequent TEAEs in the abstract.

For infection-focused events, the abstract reports oral candidiasis EAIR/100 PY of 3.5 in the axSpA cohort and 3.8 in the PsA cohort. The authors characterize most oral candidiasis cases as mild or moderate, and note that few events led to study discontinuation (EAIR/100 PY 0.2 in axSpA and 0.3 in PsA). Serious opportunistic infections are described as infrequent (EAIR/100 PY 0 in axSpA and 0.1 in PsA), and the abstract adds that no active tuberculosis was observed. In the abstract, oral candidiasis was reported (EAIR/100 PY 3.5 in axSpA and 3.8 in PsA), and serious opportunistic infections were described as infrequent.

Hepatic events are summarized in exposure-adjusted terms, with EAIR/100 PY of 5.3 in axSpA and 5.0 in PsA. The study also reports that EAIRs for several adjudicated outcomes were low, including definite/probable inflammatory bowel disease, uveitis, major adverse cardiovascular events, and suicidal ideation/behaviour. EAIRs were low for adjudicated definite/probable inflammatory bowel disease, uveitis, major adverse cardiovascular events, and suicidal ideation/behaviour.

In the conclusion, the authors state that TEAE EAIRs were similar between axSpA and PsA and that no new safety signals were identified, and they report that bimekizumab demonstrated tolerability up to five years, with phase III follow-up described as up to two years.