Treatment with bimekizumab beneficial in psoriatic arthritis

The IL-17A/IL-17F blocker bimekizumab showed marked superiority in the primary and all ranked secondary endpoints of the phase 3 BE OPTIMAL trial as a PsA therapy.

3 study arms were set up for the 16-week double blind phase

Prof. Iain McInnes (Glasgow University, UK) presented the late-breaking phase 3 results of the BE OPTIMAL study (NCT03895203) assessing bimekizumab in PsA patients who did never before receive biologics1. The trial enrolled 852 adult patients with at least 1 active PsA lesion and/or diagnosis of psoriasis. As may be expected in a trial for PsA, the baseline features of the cohort included a mean age around 49, under 50% men, and just under 60% on concomitant methotrexate. Also, about 50% of the participants had a body surface area affected by psoriasis of ≥3%.

The 16-week double-blind phase consisted of 3 study arms, in which participants were treated with placebo (n=281), bimekizumab 160 mg every 4 weeks (n=431), or adalimumab 40 mg every 2 weeks (n=140) in a reference arm. After week 16 followed an active treatment-blind period in which placebo participants were switched to bimekizumab until week 52. Prof. McInnes underlined that the study was neither designed nor powered for a head-to-head comparison of bimekizumab with adalimumab. The primary endpoint was the ACR50 response at week 16, and the results of an interim analysis at week 24 were also presented.

Bimekizumab: well tolerated except for more frequent fungal infections

The study was positive, with statistically significant more participants in the bimekizumab arm achieving ACR50 over placebo recipients at week 16: 43.9% versus 10.0% (P<0.001; odds ratio vs placebo 7.1). The respective findings for ACR20 and ACR 70 were 62.2% vs 23.8% and 24.4% vs 4.3%. “Through week 24, those responses were maintained and consistent, and the placebo patients who crossed over to bimekizumab rapidly recovered rates of response to be broadly similar to those patients, who had already achieved response by week 16,” Prof. McInnes further stated.

As for the ranked secondary outcomes, Prof. McInnes highlighted that bimekizumab was significantly superior to placebo when it came to skin amelioration at week 16 with rates of 61.3% versus 2.9% (P<0.001) reaching a Psoriasis Area and Severity Index (PASI)90 and 47.5% versus 2.1% reaching PASI100 (nominal P<0.001). Bimekizumab also significantly outperformed placebo in the achievement of minimal disease activity and inhibition of structural progression.

The safety evaluation revealed no unexpected findings. “I want to point out fungal infections, which occurred more frequently in the recipients of bimekizumab than adalimumab,” Prof. McInnes added. Overall, bimekizumab was deemed well tolerated. 

1. McInnes I, et al. Bimekizumab in bDMARD-naïve patients with psoriatic arthritis: 24-week efficacy & safety from BE OPTIMAL, a phase 3, multicentre, randomised, placebo-controlled, active reference study. LB0001, EULAR 2022, 1–4 June, Copenhagen, Denmark.