SSGJ-608 in moderate-to-severe plaque PsO: Phase III trial results

Results from a phase III, multicenter, randomized, double-blind, placebo-controlled trial (NCT05536726) evaluating SSGJ-608, an interleukin (IL)-17-targeted monoclonal antibody, in adults with moderate-to-severe plaque psoriasis (PsO) were published in the American Journal of Clinical Dermatology by Han et al. Patients were randomized 2:2:1 to receive subcutaneous (SC) SSGJ-608 80 mg every 2 weeks (Q2W) after a starting dose of 160 mg at Week 0 (608A group; n = 184), SSGJ-608 160 mg Q4W (608B group; n = 183), or placebo (n = 91). At Week 12, group 608A received SSGJ-608 80 mg Q4W, group 608B received SSGJ-608 160 mg Q8W, and patients receiving placebo were reallocated 1:1 to group 608A or 608B. The primary endpoints were the proportion of patients attaining ≥75% reduction in Psoriasis Area and Severity Index (PASI75) and the proportion of patients attaining a static Physician’s Global Assessment (sPGA) score of 0 or 1 at Week 12. 

Key data: At Week 12, PASI75 was attained by 95.1%, 93.4%, and 8.8% of patients in the 608A, 608B, and placebo groups, respectively. In the 608A, 608B, and placebo groups, an sPGA score of 0 or 1 was attained by 76.1%, 67.2%, and 1.1% of patients, respectively. At Week 52, PASI75 and an sPGA score of 0 or 1 were maintained by 93.7% and 89.3% of patients in the 608A group, respectively, and by 93.6% and 89.4% of patients in the 608B group, respectively. At Week 12, treatment-emergent adverse events (TEAEs) were reported in 71.2%, 74.3%, and 64.8% of patients in the 608A, 608B, and placebo groups, respectively, with serious adverse events (SAEs) in 1.6%, 1.1%, and 4.4% of patients, respectively. At Week 60, 94.6% and 93.4% of patients in the 608A and 608B groups experienced TEAEs. The most common TEAEs were upper respiratory tract infection (URTI), hypertriglyceridemia, and hyperuricemia. 

Key learning: In a phase III trial, SSGJ-608 demonstrated rapid, robust, and durable skin clearance through 52 weeks in patients with moderate-to-severe plaque PsO across dosing regimens, with a well-tolerated safety profile consistent with other IL-17 inhibitors. These findings support further evaluation of SSGJ-608 as a treatment option for patients with moderate-to-severe plaque PsO.