CStone Pharmaceuticals announced that the new drug application (NDA) of first-in-class precision therapy AYVAKIT ® (avapritinib) has been approved in Hong Kong, China for the treatment of adult patients with unresectable or metastatic gastrointestinal stromal tumor (GIST) harboring a PDGFRA D842V mutation. The drug is the first precision therapy approved in Hong Kong, China for the treatment of patients with PDGFRA D842V mutant GIST. Discovered by CStone's partner Blueprint Medicines, AYVAKIT is a potent, selective and orally available inhibitor of KIT and PDGFRA mutant kinases. CStone has an exclusive collaboration and license agreement with Blueprint Medicines for the development and commercialization of AYVAKIT and certain other drug candidates in Mainland China, Hong Kong, Macau and Taiwan. Blueprint Medicines retains development and commercial rights for AYVAKIT in the rest of the world.