SINOMAB BIO-B (03681) announced that on December 11, 2025, a new Investigational New Drug (IND) application for SM17 targeting inflammatory bowel disease (IBD) was submitted to and accepted by the Center for Drug Evaluation (CDE) of China's National Medical Products Administration (NMPA). Upon approval of this IND, the company's completed or ongoing Phase 1 clinical trial data from healthy volunteers can directly support advancing the IBD indication to Phase 2 clinical development.
This IND marks a significant milestone in expanding SM17's therapeutic scope from atopic dermatitis (AD) to IBD, covering chronic and debilitating conditions such as Crohn's disease (CD) and ulcerative colitis (UC), which have substantial unmet medical needs.
SM17 is a novel, first-in-class humanized IgG4-k monoclonal antibody designed to modulate type II inflammatory responses by targeting interleukin-25 (IL-25) receptor, a core "alarmin" molecule in type II immunity. By binding to IL-25 receptors (IL-17RB) on type 2 innate lymphoid cells (ILC2s) and Th2 cells, SM17 blocks IL-25-induced signaling cascades, thereby inhibiting downstream cytokines IL-4, IL-5, and IL-13. This mechanism positions SM17 as a promising candidate for treating UC, where IL-25 exerts pro-inflammatory effects.
Additionally, SM17 offers dual potential benefits in CD: regulating Th17-driven inflammation while exerting anti-fibrotic effects, which may help alleviate complications like intestinal strictures and fistulas. This multi-mechanistic profile distinguishes SM17 from existing single-pathway therapies, providing a novel treatment option for refractory or complex phenotypes.
IL-25 is a key cytokine implicated in the pathological changes of IBD, including CD and UC. These chronic inflammatory bowel diseases stem from dysfunctional immune responses to normally harmless commensal bacteria, categorized into Th1-, Th2-, or Th17-driven pathways, each associated with specific cytokine profiles.
IBD patients often experience severe diarrhea, abdominal pain, rectal bleeding, and weight loss, with late-stage complications including fistulas, intestinal strictures, and even colectomy. Beyond physical burdens, IBD's recurrent nature significantly impairs quality of life, accompanied by high rates of anxiety, depression, and reduced work capacity. Global annual costs for IBD management exceed $34 billion.
Current therapies—including TNF blockers, anti-integrin drugs, and IL-12/23 inhibitors—fail to address 20%–50% of patients due to primary non-response or secondary loss of response within 1–2 years, particularly in fistulizing CD or extensive intestinal lesions. This challenge arises from IBD's highly heterogeneous pathological pathways, where targeting a single cytokine proves insufficient across patient subgroups. Moreover, the lack of anti-fibrotic activity in existing therapies allows persistent tissue remodeling in complex cases. Long-term use also raises safety concerns, including infection and malignancy risks.
SM17 is currently undergoing bridging clinical trials for formulation conversion, expected to conclude by late February next year, with Phase 2 trials for AD anticipated by mid-2026. The company views SM17's expansion from AD to IBD as a critical opportunity to address unmet needs in this clinically and commercially significant field. Targeting upstream Th2 inflammatory pathways (e.g., IL-25 receptor) may offer broad efficacy in skin inflammation, underscoring SM17's potential as a safer, more effective, and differentiated therapy for AD.
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