Bimekizumab in patients with active psoriatic arthritis: results from a 48-week, randomised, double-blind, placebo-controlled, dose-ranging phase 2b trial

SPS commentary:

The study reported that at 12 weeks, compared with placebo, significantly more patients in 16 mg (OR 4.2 [95% CI 1.1–15.2]; p=0.032), 160 mg (8.1 [2.3–28.7]; p=0.0012), and 160 mg (with loading dose; (9.7 [2.7–34.3]; p=0.0004) groups achieved an ACR50 response.

 

According to a commentary, interpretation of the results of this trial is not straightforward because a hierarchy of sequential pairwise comparisons starting with the highest dose (320mg) versus placebo for ACR50 response at week 12 was predefined, and, by contrast with the significant efficacy results with the 320mg dose in other studies, response in the 320 mg group did not differ significantly from that in the placebo group at 12 weeks (odds ratio 3.7 [95% CI 1.0–13.7]; p=0.051). It considers that all further outcomes was considered exploratory, and formal conclusions were not drawn about them, therefore p values obtained from significance testing of all subsequent doses and secondary endpoints were judged to be nominal only. It adds that perhaps because of the small number of patients followed up for 48 weeks, no new IL17 inhibitor safety signals were reported, and the number needed to harm per serious adverse event was 22. It notes bimekizumab will move forward to a phase 3 clinical trial to clarify the optimal dose and the necessity for a loading dose, to further characterise efficacy in all domains of psoriatic arthritis, to capture imaging data, and to further define safety. It concludes that for now, the superiority of dual inhibition of IL17A and IL17F over inhibition of IL17A alone remains to be confirmed.