Efficacy and Safety of GR1802 in Patients With Moderate‐to‐Severe Atopic Dermatitis: A Multicenter, Randomized, Double‐Blind, Placebo‐Controlled Phase 2 Trial

Background: GR1802 is a newly developed, fully humanized monoclonal antibody targeting the interleukin‐4 receptor alpha (IL‐4Rα) subunit, which is a component common to both the IL‐4 and IL‐13 receptor complexes. Objectives: Our objective was to assess the efficacy of GR1802 in adult patients presenting with moderate‐to‐severe atopic dermatitis. Methods: In this clinical trial, patients with moderate‐to‐severe atopic dermatitis were randomly assigned to receive either 300 mg GR1802, 150 mg GR1802, or a placebo every 2 weeks for 16 weeks. Primary endpoints were the Eczema Area and Severity Index (EASI‐75) response rates at Week 16. Secondary efficacy outcomes included responders at various evaluation points from baseline to study end: IGA 0/1 with ≥ 2‐point improvement; EASI‐75, EASI‐90, and EASI‐50; and ≥ 3‐ or ≥ 4‐point improvements in weekly average daily PP‐NRS score. Safety was evaluated throughout the study. Results: From August 2022 to February 2023, 120 patients were randomized to receive either GR1802 150 mg ( n = 40), GR1802 300 mg ( n = 40), or placebo ( n = 40), with 107 completing the study. GR1802 demonstrated a higher proportion of patients achieving EASI‐75 at Week 16 compared with the placebo group, and the observed differences in EASI‐75 response rates were 39.1% (GR1802 300 mg vs. placebo, 95% CI 20.0–58.2, p = 0.0002) and 19.4% (GR1802 150 mg vs. placebo, 95% CI −0.8–39.7, p = 0.0740). The GR1802 300 mg group also showed greater efficacy on secondary endpoints compared to the GR1802 150 mg group. Serious adverse events occurred in 10% of placebo patients, 2.5% of the GR1802 150 mg group, and none in the GR1802 300 mg group. Treatment‐emergent AEs occurred in 75.0% of the GR1802 150 mg group, 82.5% of the GR1802 300 mg group, and 85.0% of the placebo group. Conclusions: GR1802 was well tolerated and effective in moderate‐to‐severe AD patients, showing a dose–response trend at 150–300 mg. Trial Registration: Chinese Registry of Clinical Trials: ChiCTR2100051917