SINOMAB BIO-B (03681): The first patient in China with atopic dermatitis completes Phase 2 clinical trial of SM17 treatment.

SINOMAB BIO-B (03681) announced that the Phase 2 clinical trial of SM17 for the treatment of atopic dermatitis was successfully completed with the first patient dosed in China on March 31, 2026. This Phase 2 study is a multicenter randomized double-blind, placebo-controlled clinical trial aimed at evaluating the efficacy and safety of the subcutaneous formulation of SM17 in approximately 210 patients with moderate to severe atopic dermatitis. Patients will be randomly divided into 5 groups in a 1:1:1:1:1 ratio and receive different doses of SM17 or placebo subcutaneous treatment. The primary endpoint is the percentage change in eczema area and severity index (EASI) from baseline at week 16, with secondary endpoints (including other efficacy endpoints such as the proportion of subjects achieving EASI50, EASI75, EASI90, IGA0/1, the occurrence rate of treatment-emergent adverse events (TEAE) defined safety endpoint, as well as pharmacokinetic (PK) characteristics, pharmacodynamic (PD) characteristics and immunogenicity) to be evaluated at week 16 and other time points during the study period until week 24. SM17 is a novel, global first-in-class humanized IgG4-k monoclonal antibody designed to regulate type 2 inflammatory responses by targeting interleukin 25 (IL-25, a sentinel molecule that plays a central role in type 2 immunity). by binding to the IL-25 receptor (IL-17RB) on type 2 innate lymphoid cells (ILC2s) and Th2 cells, inhibiting IL-25-mediated signaling and downstream inflammatory cytokines, including interleukins IL-4, IL-5, IL-13. IL-25 is a key cellular factor of the crucial "sentinel" cytokine class, that has been linked to the pathogenesis of various inflammatory and immune diseases such as atopic dermatitis, asthma, and inflammatory bowel disease (IBD). Despite advances in targeted therapy, such chronic inflammatory and immune-mediated diseases still pose a heavy disease burden, including persistent symptoms, progressive tissue damage, and severely impaired quality of life. Current treatment options, although effective for many patients, are often limited by safety issues, poor compliance, and failure of some patients to achieve lasting relief. These unmet medical needs underscore the continued demand in the market for novel treatment options with better convenience, good safety and differentiated efficacy. On April 7, 2025, the company announced positive top-line results of the Phase 1b study of SM17 in Chinese patients with moderate to severe atopic dermatitis. The main data after 12 weeks of unblinding showed that in the high-dose group, 91.7% of patients achieved itch relief (NRS-4), 75% achieved skin lesion healing (EASI 75), and 41.7% achieved complete or nearly complete clearance of atopic dermatitis signs (IGA 0/1). These results demonstrate the competitive advantage of SM17 as a potential first biologic agent with dual effects of relieving itching and repairing skin in atopic dermatitis. On March 27, 2026, the company announced ideal top-line results from a Phase 1 bridging study of the route conversion of SM17 administration: healthy subjects who received subcutaneous formulation showed good tolerability and safety, and the pharmacokinetic characteristics of the subcutaneous formulation supported a smooth transition of the administration route. The company believes that upstream therapies targeting Th2 inflammatory cytokine pathways (such as IL-25 receptor) will have broad effects on skin inflammation, indicating that SM17 has great potential in atopic dermatitis treatment as a safer and more effective and differentiated therapeutic option.