CStone’s CS2015 antibody debuts at international medical conference

CStone Pharmaceuticals announced the international debut of its autoimmune and inflammation pipeline asset, CS2015 (OX40L/TSLP bispecific antibody), at the 2025 Annual Scientific Meeting of the American College of Allergy, Asthma and Immunology (ACAAI). This marked the first public presentation of CS2015 at an international academic conference, where it was featured as an ePoster and an on-site oral presentation. The full abstract and ePoster content are now available on the ACAAI website.

CS2015, featuring an asymmetric molecular design, simultaneously targets OX40L and TSLP, two clinically validated critical regulators of type 2 inflammation. The molecule demonstrated potent inhibition of OX40L/OX40 and TSLP/TSLPR downstream signaling, with blocking activities comparable to benchmark antibodies, achieving single or sub-nanomolar IC50s. Furthermore, CS2015 exhibited superb pharmacokinetic (PK) profiles in Non-Human Primates (NHP), with a mean half-life of 21 days via subcutaneous administration and 25.7 days intravenously, supporting long-term dosing intervals and demonstrating outstanding bioavailability.

The drug also showed robust inhibition of inflammatory responses, reducing inflammatory cytokines from primary CD4+ T cells stimulated by TSLP/OX40L and suppressing TSLP-induced TARC (CCL17) release in human monocytes and PBMCs. Early signs of efficacy were observed in Atopic Dermatitis models, where CS2015 rapidly reduced skin lesion severity, decreased immune cell infiltration, and lessened itch events. CStone plans to advance CS2015 for various Th2 cell-mediated inflammation diseases, including Atopic Dermatitis, asthma, and chronic obstructive pulmonary disease.