Keymed Biosciences Inc. announced that the long-term efficacy and safety data of a Phase III clinical trial (NCT05265923) of stapokibart injection in patients with moderate-to-severe atopic dermatitis (AD) has been released by way of oral presentation at the European Academy of Allergy and Clinical Immunology (EAACI) Congress 2024. This multicenter, randomized, double-blind, placebo-controlled phase III trial was designed to assess the efficacy, safety, pharmacokinetics, pharmacodynamics, and immunogenicity of stapokibart in patients with moderate-to-severe AD. During the double-blind treatment period, a total of 500 adult patients with moderate-to-severe AD were randomized 1:1 to receive stapokibart 300 mg (loading dose: 600 mg) or placebo every two weeks for 16 weeks.

In the subsequent 36-week maintenance treatment period, patients in the stapokibart group continued the same dose, and patients switching from placebo to stapokibart received stapokibart 300 mg (loading dose: 600 mg) every 2 weeks. Concomitant use of topical medications for AD treatment was permitted during the maintenance treatment period. The co-primary endpoints of this trial were the proportions of patients achieving 75% improvement from baseline in Eczema Area and Severity Index score (EASI-75) and an Investigator's Global Assessment (IGA) score of 0/1 with a 2 point reduction from baseline at week 16.

Other efficacy measures included EASI score, IGA score, and Peak Pruritus Numerical Rating Scale (PP-NRS), etc. A total of 476 patients entered the maintenance treatment period, with 238 in each group. At week 52, EASI-75 was achieved in 92.5% of patients continuing stapokibart and 88.7% of those switching from placebo to stapokibart, IGA score of 0/1 with a 2-point reduction was achieved in 67.3% and 64.2%, respectively; a 4-point reduction in weekly average of daily PP-NRS was achieved in 67.3% and 60.5%, respectively.

Long-term treatment with stapokibart continuously improved AD symptoms and quality of life of patients with moderate-to-severe AD. Only 1 patient (0.9%) relapsed during the maintenance period. In terms of safety, stapokibart was well-tolerated, and its safety profile over 52 weeks was consistent with the initial 16-week double-blind period, with no new safety signals identified.

Overall, long-term treatment with stapokibart demonstrated sustained efficacy and favorable safety profile in adult patients with moderate-to-severe AD, and no new safety signals were observed.