Efficacy and safety of ixekizumab in a randomized, double-blinded, placebo-controlled phase IIIb study of patients with moderate-to-severe genital psoriasis.

Background: Genital psoriasis (GenPs) is a common, debilitating and difficult-to-treat manifestation of plaque psoriasis. However, few controlled, interventional studies of GenPs exist.

Objectives: To determine the efficacy of ixekizumab vs. placebo in patients with moderate-to-severe GenPs with ≥ 1% involved body surface area (BSA).

Methods: Patients with moderate-to-severe GenPs, defined as a baseline static Physician's Global Assessment of Genitalia (sPGA-G) score of ≥ 3, with BSA ≥ 1% were randomized 1 : 1 to receive placebo (n = 74) or the recommended dosing of ixekizumab (n = 75). Major outcomes included the percentage of patients achieving 0 or 1 scores on the sPGA-G (primary end point), overall sPGA, GenPs Sexual Frequency Questionnaire (GenPs-SFQ) item 2, and ≥ 3-point improvement from baseline on the GenPs itch numerical rating scale.

Results: At week 12, ixekizumab was superior to placebo for sPGA-G 0/1 (73% vs. 8%, P < 0·001), overall sPGA 0/1 (73% vs. 3%, P < 0·001), GenPs-SFQ item 2 score of 0 or 1 (78% vs. 21%, P < 0·001) and genital itch (60% vs. 8%, P < 0·001). No candidiasis was reported, no deaths occurred and one (1%) serious adverse event was reported in a patient receiving placebo.

Conclusions: Ixekizumab was superior to placebo for the treatment of moderate-to-severe GenPs with BSA ≥ 1%. The safety profile of ixekizumab was consistent with previous studies in moderate-to-severe plaque psoriasis.