Efficacy and Safety of Recibokibart, an Interleukin-36 Receptor Antibody, in Generalized Pustular Psoriasis: A Phase 2 Randomized Trial

Why clinicians should know about it

• Picked for Dermatology (paper of the day, 5 September 2026): Phase 2 RCT of IL‑36R antibody in generalized pustular psoriasis

Abstract

BACKGROUND: Generalized pustular psoriasis (GPP) is a rare, severe inflammatory skin disease characterized by acute flares. Recibokibart is a humanized IgG1 monoclonal antibody targeting the interleukin-36 (IL-36) receptor. In a phase 1b open-label study, a single intravenous dose of recibokibart was associated with an acceptable safety profile and rapid improvements in pustulation, overall skin disease severity, and systemic inflammatory markers through 12 weeks. OBJECTIVES: This study aimed to evaluate the efficacy and safety of recibokibart in patients with acute flares of GPP. METHODS: In this multicenter, randomized, double-blind, placebo-controlled phase 2 trial conducted in China, patients with moderate-to-severe acute GPP were randomly assigned in a 2:1 ratio to receive a single intravenous dose of recibokibart (1050 mg) or placebo at day 1. Patients with persistent disease activity at day 8 were eligible to receive open-label recibokibart, and patients with recurrent flares after achieving a Generalized Pustular Psoriasis Physician Global Assessment (GPPGA) total score of 0 or 1 could receive an additional open-label dose. The primary efficacy endpoint was the proportion of patients who achieved a GPPGA pustulation sub-score of 0 or 1 at week 1 (day 8). RESULTS: A total of 33 patients were randomized (recibokibart, n=22; placebo, n=11). At week 1 (day 8), the primary endpoint of achieving a GPPGA pustulation sub-score of 0 or 1 was met by 86.4% of patients in the recibokibart group versus 9.1% in the placebo group (between-group difference, 77.3%; 95% CI, 42.5-88.9; P<0.0001). At week 1 (day 8), greater improvements were observed with recibokibart across key secondary endpoints, including achievement of a GPPGA total score of 0 or 1 (63.6% vs. 0%), complete pustule clearance (54.5% vs. 0%), and mean percentage change from baseline in GPPASI (-59.3% vs. 0%). By week 4, 72.7% of patients treated with recibokibart achieved GPPASI 75. Clinical improvements were observed as early as 24 hours after treatment and were maintained through week 12, although assessments after day 8 included patients who received open-label treatment. The most frequently reported adverse events with recibokibart included hypoproteinemia, hypertriglyceridemia, hyperlipidemia, and pruritus. CONCLUSIONS: A single intravenous dose of recibokibart resulted in rapid improvement in pustular and overall skin disease severity in patients with acute GPP flares, with an acceptable safety profile.

Abstract as published, via PubMed.