CStone Pharmaceuticals announced that the Company has entered into an agreement with Jiangsu Hengrui Pharmaceuticals Co., Ltd. to grant the exclusive promotion rights of precision therapy AYVAKIT® (avapritinib tablets) in mainland China to Hengrui. Except for promotion, CStone retains all rights to AYVAKIT® in mainland China, including rights to development, registration, manufacturing and distribution, etc. Key Highlights With CStone's outstanding clinical development capability, AYVAKIT® has become the first precision therapy approved in China for adults with unresectable or metastatic gastrointestinal stromal tumors (GIST) harboring the PDGFRA exon 18 mutation, including the PDGFRA D842V mutation, which helps address unmet medical needs for this patient population.

AYVAKIT® has also been listed under the National Reimbursement Drug List (NRDL) in China. With Hengrui's extensive and robust commercial infrastructure, this partnership is expected to further maximize the commercial potential of AYVAKIT®. Under the terms of the agreement, CStone will receive an upfront payment of RMB 35 million and will continue to book sales revenue from AYVAKIT® in mainland China in its financial reports, and Hengrui will charge CStone a service fee.

AYVAKIT®, a potent, selective and orally available inhibitor of KIT and PDGFRA mutant kinases, was approved by the National Medical Products Administration of China (NMPA) in March 2021 for the treatment of adults with unresectable or metastatic GIST harboring the PDGFRA exon 18 mutation, including PDGFRA D842V mutations. The manufacturing localization registration application for AYVAKIT® (300mg) was approved by the NMPA in June 2024 and domestic supply is expected to be available by the end of 2024 or early 2025. As part of its commercialization efforts in Greater China, CStone has advanced the clinical implementation of precision medicine approaches through physician engagement and education, as well as the standardization of diagnosis and treatment.

AYVAKIT® is now included in the NRDL, making it more accessible and affordable. It has also been recommended by multiple domestic and international guidelines, including the 2023 CSCO Guidelines for Gastrointestinal Stromal Tumor Diagnosis and Treatment, the 2022 Clinical Practice Guidelines for the Pathological Diagnosis of Gastrointestinal Stromal Tumors, the Chinese Guidelines for the Diagnosis and Treatment of Systemic Mastocytosis, the 2023 NCCN Guidelines for Gastrointestinal Stromal Tumors, and the 2023 NCCN Guidelines for Systemic Mastocytosis. AYVAKIT® was discovered by CStone's partner Blueprint Medicines.

In 2018, CStone entered into an exclusive collaboration and license agreement with Blueprint Medicines for the development and commercialization of AYVAKIT® in the Greater China Region, including mainland China, Hong Kong, Macau and Taiwan.