Bimekizumab versus Secukinumab in Plaque Psoriasis

BACKGROUND: Bimekizumab is a monoclonal IgG1 antibody that selectively inhibits both interleukin-17A and interleukin-17F. The efficacy and safety of bimekizumab as compared with secukinumab, which selectively inhibits interleukin-17A alone, in patients with moderate-to-severe plaque psoriasis have not been extensively examined. METHODS: In this phase 3b trial, we randomly assigned patients with moderate-to-severe plaque psoriasis, in a 1:1 ratio, to receive bimekizumab subcutaneously at a dose of 320 mg every 4 weeks or secukinumab subcutaneously at a dose of 300 mg weekly to week 4, followed by every 4 weeks to week 48. At week 16, patients receiving bimekizumab underwent rerandomization, in a 1:2 ratio, to receive maintenance dosing every 4 weeks or every 8 weeks to week 48. The primary end point was 100% reduction from baseline in the Psoriasis Area and Severity Index (PASI) score at week 16. The primary analysis was first tested for the noninferiority of bimekizumab to secukinumab at a margin of -10 percentage points and then tested for superiority. RESULTS: A total of 1005 patients were screened and 743 were enrolled; 373 patients were assigned to receive bimekizumab and 370 to receive secukinumab. At week 16, a total of 230 patients (61.7%) in the bimekizumab group and 181 (48.9%) in the secukinumab group had a 100% reduction from baseline in the PASI score (PASI 100) (adjusted risk difference, 12.7 percentage points; 95% confidence interval [CI], 5.8 to 19.6); bimekizumab was shown to be noninferior and superior to secukinumab (P<0.001 for noninferiority and superiority). At week 48, a total of 250 patients (67.0%) treated with bimekizumab had a PASI 100 response, as compared with 171 patients (46.2%) treated with secukinumab (adjusted risk difference, 20.9 percentage points; 95% CI, 14.1 to 27.7; P<0.001). At the week 4 time point, 265 patients (71.0%) in the bimekizumab group had 75% or greater reduction from baseline in the PASI score, as compared with 175 patients (47.3%) in the secukinumab group (adjusted risk difference, 23.7; 95% CI, 17.0 to 30.4; P<0.001). Oral candidiasis occurred more often with bimekizumab (72 patients, 19.3%) than with secukinumab (11 patients, 3.0%). CONCLUSIONS: In patients with moderate-to-severe psoriasis, treatment with bimekizumab resulted in greater skin clearance than treatment with secukinumab over 16 and 48 weeks but was associated with oral candidiasis (predominantly mild or moderate as recorded by the investigator). Longer and larger trials are required to determine the comparative effect and risks of interleukin-17 inhibitors in psoriasis. (Funded by UCB Pharma; BE RADIANT ClinicalTrials.gov number, NCT03536884.).