SINOMAB BIO-B (03681) announced that on February 24, 2026, the Investigational New Drug (IND) application for its first-in-class (FIC) therapeutic product SM17, intended for the treatment of patients with inflammatory bowel disease (IBD), was approved by China's National Medical Products Administration (NMPA). This IND approval marks a significant milestone in expanding the therapeutic scope of SM17 from atopic dermatitis (AD) to IBD, encompassing chronic and debilitating conditions such as Crohn's disease (CD) and ulcerative colitis (UC), which represent areas of significant unmet medical need. The company has completed follow-up for a Phase I bridging study in healthy volunteers using a subcutaneous formulation of SM17. The resulting research data will be used to support the direct progression into Phase II clinical development for the IBD indication. SM17 is a novel, first-in-class, humanized IgG4-k monoclonal antibody designed to modulate type 2 inflammatory responses by targeting the interleukin-25 (IL-25) receptor, a core "alarmin" molecule in type 2 immunity. By binding to the IL-25 receptor (IL17RB) on the surface of type 2 innate lymphoid cells (ILC2s) and Th2 cells, SM17 inhibits IL-25-mediated signaling and downregulates downstream inflammatory cytokines, including interleukin-4, interleukin-5, and interleukin-13. This mechanism positions SM17 as a promising therapeutic candidate for UC, where IL-25 has been demonstrated to play a pro-inflammatory role. Furthermore, SM17 may offer benefits for CD by regulating Th17-related inflammation and exerting potential anti-fibrotic effects, which could help improve transmural inflammatory complications in CD, such as intestinal strictures and fistulas. This multi-mechanistic profile distinguishes SM17 from existing single-pathway therapies, offering a novel treatment option for patients with refractory or complex disease phenotypes. Concurrent with the IND advancement, SM17 is currently completing a bridging study to transition from an intravenous to a subcutaneous formulation, with completion expected as early as the first quarter of this year. The company anticipates initiating a Phase II clinical trial for AD as early as the second quarter of this year. The company believes that expanding the indication of SM17 from AD to IBD represents a significant opportunity to address unmet medical needs in an area of substantial clinical and commercial value. The company further believes that a therapeutic strategy targeting upstream regulators of the type 2 inflammatory pathway, such as the IL-25 receptor, supports the potential for SM17 to become a differentiated, safer, and effective treatment option for both AD and IBD.