Ruishi Biopharmaceutical

Reistone Biopharma (Ruishi Biopharmaceutical) was a clinical-stage biopharmaceutical company founded in 2018 and headquartered in Shanghai, China, with additional operations in Beijing and Boston. The company specialized in developing innovative therapies for autoimmune and inflammatory diseases, primarily focusing on small molecule inhibitors. Its lead asset, ivarmacitinib (SHR0302), is a highly selective Janus kinase 1 (JAK1) inhibitor that reached Phase 3 clinical trials for multiple indications, including atopic dermatitis, ulcerative colitis, and alopecia areata. Other notable programs in its pipeline included RSS0343, a DPP-1 inhibitor for respiratory diseases, and RSS0393, a PDE4 inhibitor for dermatological conditions. Reistone was incubated and majority-owned by Jiangsu Hengrui Pharmaceuticals, which provided the initial licenses for its core assets. In September 2023, Jiangsu Hengrui reportedly dissolved Reistone Biopharma and re-absorbed its pipeline and operations into the parent company's internal R&D structure.