By Fineline Cube 
Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (HKG: 6990) announced on July 23, 2025, that its partner Windward Bio has officially commenced the global Phase II clinical study (POLARIS trial) for SKB378/WIN378 in the treatment of asthma. This trial aims to assess the drug’s efficacy, safety, and dosing regimen, with preliminary data expected in mid-2026.
Drug Mechanism and Profile
SKB378/WIN378 is a novel, engineered recombinant fully human anti-TSLP monoclonal antibody. It features an extended half-life and silenced effector function, enabling subcutaneous administration. By binding to the TSLP ligand with high affinity, it blocks inflammatory signaling pathways, offering potential benefits in immune-related diseases such as asthma and COPD.
Clinical Development Progress
The drug has completed Phase I clinical studies, demonstrating good safety, low anti-drug antibody incidence, and pharmacokinetic properties supporting long-acting dosing. In January 2025, it received IND approval from China’s National Medical Products Administration (NMPA) for COPD treatment. Kelun-Biotech plans to advance related studies, including for COPD, in 2026.
Collaboration and Licensing
Initially co-developed by Kelun-Biotech and Harbour BioMed, SKB378/WIN378’s global rights (excluding Greater China and certain Asian countries) were exclusively licensed to Windward Bio in January 2025. Windward Bio, a clinical-stage biotech company established in early 2025, has secured $200 million in Series A financing.-Fineline Info & Tech