CStone Pharmaceuticals announced that the detailed registrational data of selective RET inhibitor GAVRETO? (pralsetinib) for the treatment of Chinese patients with advanced or metastatic RET-mutant medullary thyroid cancer (MTC) in the ARROW study, a global phase 1/2 clinical study, has been presented during a late breaking oral abstract session at the 90th Annual Meeting of the American Thyroid Association (ATA) 2021. Primary efficacy results showed GAVRETO had broad and durable anti-tumor activity in the Chinese patients with advanced or metastatic RET-mutant MTC, consistent with the data previously reported in the global ARROW study. The safety profile was manageable, with no new safety signals detected. Discovered by CStone's partner Blueprint Medicines, GAVRETO is the first selective RET inhibitor in China approved for the treatment of adults with local advanced or metastatic RET fusion-positive NSCLC after platinum-based chemotherapy. CStone has an exclusive collaboration and license agreement with Blueprint Medicines for the development and commercialization of GAVRETO in Greater China, which encompasses Mainland China, Hong Kong, Macau and Taiwan. Efficacy: GAVRETO showed robust and durable anti-tumor activity in Chinese patients with advanced or metastatic RET-mutant MTC who require systemic therapy- The confirmed ORR of 26 RET-mutant MTC patients with measurable disease at baseline was 73.1%, including 3 with complete response (CR) and 16 with partial responses (PR); the disease control rate (DCR) reached 84.6%. Responses were observed regardless of RET mutation genotype. Among the 19 patients with confirmed response, the median DOR was not reached, and the 9-month DOR rate was 100%. Calcitonin and carcinoembryonic antigen (CEA) levels were substantially reduced. Safety: GAVRETO was well tolerated and had a generally manageable safety profile- GAVRETO was well-tolerated. The overall safety in Chinese patients was generally manageable, with no new safety signals detected.