Efficacy and Safety of SSGJ-608 in Moderate-to-Severe Plaque Psoriasis: A Pivotal Multicenter, Double-Blind, Placebo-Controlled, Randomized, Phase III Clinical Trial

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• Picked for Dermatology (top studies of the week, 23 August 2026): Phase III trial of SSGJ-608 in moderate-to-severe psoriasis

Abstract

BACKGROUND: SSGJ-608 is a recombinant, humanized, immunoglobulin G1 monoclonal antibody that targets human interleukin-17A with high specificity and high affinity. OBJECTIVE: We aimed to evaluate the efficacy and safety of SSGJ-608 in patients with moderate-to-severe psoriasis in China. METHODS: Adult patients aged 18 years or older with moderate-to-severe plaque psoriasis were randomly assigned (2:2:1) to receive subcutaneous injections of placebo (placebo group), 80 mg of SSGJ-608 every 2 weeks after a starting dose of 160 mg at week 0 (608A group), or 160 mg of SSGJ-608 every 4 weeks (608B group). At week 12, patients in the 608A group received SSGJ-608 80 mg every 4 weeks, patients in the 608B group received SSGJ-608 160 mg every 8 weeks, and patients in the placebo group were re-allocated (1:1) to either the 608A or 608B group to receive 608 80 mg every 4 weeks (with an additional 160-mg loading dose of SSGJ-608 at week 12) or 160 mg every 8 weeks. All patients received treatment until week 48. The primary endpoints were a ≥75% improvement from baseline in the Psoriasis Area and Severity Index score (PASI75) and a static Physicians Global Assessment score of 0/1 (sPGA 0/1) at week 12. RESULTS: A total of 458 patients were randomly assigned to either the 608A group (n = 184), the 608B group (n = 183), or the placebo group (n = 91). At week 12, compared with those in the placebo group, a greater proportion of patients in the 608A group and in the 608B group achieved the primary endpoints of PASI75 (95.1% vs 93.4% vs 8.8%) and sPGA of 0 or 1 (76.1% vs 67.2% vs 1.1%). At week 52, PASI75 was maintained by 93.7% in the 608A group and 93.6% in the 608B group, sPGA of 0 or 1 was maintained by 89.3% in the 608A group and 89.4% in the 608B group, PASI90 was maintained by 92.6% in the 608A group and 92.5% in the 608B group, respectively. Both treatment groups demonstrated a favorable safety profile, with no increase in risk observed with longer drug exposure. CONCLUSIONS: SSGJ-608 showed rapid and robust clinical response at week 12 and through week 52, and was well tolerated in Chinese patients with moderate-to-severe plaque psoriasis. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifiers: NCT05536726.

Abstract as published, via PubMed.