BSI-502

BSI-502 is a humanized anti-TSLP and anti-IL-4R bispecific antibody designed to block upstream TSLP receptor signaling and downstream IL-4R activation, thereby suppressing this primary pro-inflammatory pathway. BSI-502 has received IND approval in the United States, and Aclaris initiated the clinical trial in the second quarter of 2025 (2Q 2025). Aclaris holds the exclusive rights for this project outside of the Greater China region, while CTTQ and Biosion jointly retain the development and commercialization rights within Greater China.