Journal of Clinical and Aesthetic Dermatology • Hot Topics in Psoriasis February 2024 • Research Summary—Bimekizumab Efficacy And Safety In Patients With Moderate-To-Severe Plaque Psoriasis: Two-Year Interim Results From The Open-Label Extension Of The Randomized BE RADIANT Phase IIIb Trial

Interleukin (IL)-17A and IL-17F contribute to plaque psoriasis. The monoclonal immunoglobulin G1 (IgG1) antibody bimekizumab selectively inhibits both IL-17A and IL-17F, and Phase III clinical trials have demonstrated its efficacy in treating moderate-to-severe plaque psoriasis. Data from Year 1 of the BE RADIANT trial showed that bimekizumab had superior efficacy compared to secukinumab, an IL-17A inhibitor, over 48 weeks. In this study, Strober et al1 reported interim results from the open-label extension (OLE) of the BE RADIANT trial. Their findings are summarized below.

Patients who completed the 48-week double-blinded period, which consisted of a 16-week initial treatment period and 32- week maintenance period, of the Phase IIIb, multicenter BE RADIANT trial were eligible to enroll in the OLE. Patients were initially randomized to receive bimekizumab 320mg every four weeks or secukinumab 300mg weekly for four weeks, then every four weeks thereafter. Patients in the bimekizumab group were rerandomized to receive treatment every four or eight weeks at Week 16 until Week 48; however, following a protocol amendment, all patients treated with bimekizumab received treatment every eight weeks, starting at their next scheduled visit or after Week 64. Patients in the secukinumab group switched to bimekizumab at Week 48, the start of the OLE. The OLE extended to Week 144; interim analysis was conducted at Week 96.

A total of 336 of 373 patients (90.1%) in the bimekizumab group and 318 of 370 (85.9%) in the secukinumab group enrolled in the OLE. In the continuous bimekizumab treatment group, the proportion of patients who achieved 100-percent reduction in Psoriasis Area and Severity Index score (PASI100) from Week 48 (74.8%) to Week 96 (70.8%) was maintained. Achievement of PASI100 was similar for patients who received treatment every four weeks and those treated every eight weeks. Among those who switched from secukinumab to bimekizumab, rates of PASI100 increased from 52.8 percent at Week 48 to 76.6 percent at Week 96.

Investigator’s Global Assessment (IGA) 0/1 (clear/almost clear skin) was reached by 94 percent of patients in the continuous bimekizumab group at Week 48; this rate was similar at Week 96, with 90.9 percent of patients achieving IGA 0/1. Rates of IGA 0/1 were similar among patients treated every four weeks and those treated every eight weeks. Additionally, the proportion of patients who achieved IGA 0/1 in the secukinumab/bimekizumab group rose slightly from Week 48 (85.1%) to Week 96 (90.7%).

In the continuous bimekizumab group, 88.9 and 86.9 percent of patients achieved affected body surface area (BSA) of one percent or less at Week 48 and 96, respectively, with similar trends among patients treated every four weeks and those treated every eight weeks. Rates of affected BSA of one percent or less increased from 75.9 percent at Week 48 to 87.4 percent at Week 96 among patients who switched from secukinumab to bimekizumab.

At Week 48, the proportion of patients with Dermatology Life Quality Index (DLQI) scores of 0/1, indicating no effect of psoriasis on quality of life, was higher in the continuous bimekizumab treatment group, at 87.4 percent, compared to the secukinumab/bimekizumab group, at 80.7 percent. Results were maintained for both groups at Week 96 (86.3% and 81.5%, respectively).

In Year 2 of the BE RADIANT trial, the exposure-adjusted incidence rate (EAIR) of any treatment-emergent adverse event (TEAE) was 131.6 per 100 person-years in the continuous bimekizumab group and 158.7 per 100 personyears in the secukinumab/bimekizumab group. Overall, EAIRs for any TEAE in Year 2 were lower than in Year 1. The EAIRs for serious adverse events were similar in both groups, at 5.0 and 5.3 per 100 person-years for the continuous bimekizumab and secukinumab/bimekizumab groups, respectively.

Nasopharyngitis, oral candidiasis, and urinary tract infection were the most common TEAEs across both groups. Among patients treated with continuous bimekizumab, the EAIRs for nasopharyngitis, oral candidiasis, and urinary tract infection were 11.8, 7.8, and 4.5 per 100 person-years, respectively; for those who switched from secukinumab to bimekizumab, EAIRs were 12.1, 12.2, and 5.7 per 100 personyears, respectively. The rates of nasopharyngitis were lower in Year 2, compared to Year 1. Concerning TEAEs of interest, the most common in both treatment groups were fungal infections, Candida infections, and oral candidiasis. The EAIRs of TEAEs of interest were generally lower in Year 2, compared to Year 1.

One limitation of this study was the limited racial diversity, as most participants were White. Additionally, the onset of the COVID-19 pandemic might have affected data. Confounding factors, such as social isolation, lockdowns, and wearing masks, might have affected AE rates, especially for respiratory AEs.

The findings of this interim analysis demonstrated the treatment with bimekizumab over 96 weeks was safe and effective in patients with moderate-to-severe plaque psoriasis. Safety data for bimekizumab were consistent with the known safety profile. Furthermore, patients who switched from secukinumab to bimekizumab experienced treatment improvements, indicating that bimekizumab was more effective than secukinumab. This finding also suggests that switching from another anti-IL-17 biologic to bimekizumab is effective and well tolerated among patients with moderate-to-severe plaque psoriasis.