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CStone Submits Ayvakit for Approval in Taiwan for PDGFRA Exon 18-Mutated Stomach Cancer

NEW YORK – CStone Pharmaceuticals said on Friday that it submitted a new drug application for its precision cancer drug avapritinib (Ayvakit) to the Taiwan Food and Drug Administration.

The drugmaker is advancing avapritinib as a treatment for patients with unresectable or metastatic gastrointestinal stromal tumors harboring a PDGFRA exon 18 mutation, including PDGFRA D842V. The US Food and Drug Administration in January approved the drug for this same indication.

Blueprint Medicines discovered avapritinib, a PDGFRA and KIT inhibitor. CStone and Blueprint have an exclusive collaboration and licensing agreement to develop and commercialize the drug in Mainland China, Hong Kong, Macau, and Taiwan.

Clinical data submitted to the TFDA showed that 84 percent of advanced GIST patients with PDGFRA exon 18 mutations, including PDGFRA D842V, experienced tumor shrinkage on avapritinib. The median duration of response was not reached at the time of data collection, and 61 percent of patients responded for more than six months.

Around 90 percent of GIST patients have mutations in KIT and PDGFRA. Most GIST patients don't respond to chemotherapy and radiotherapy.

"GIST is a rare tumor type, and PDGFRA D842V mutant GIST is resistant to currently approved therapies in greater China," CStone CEO Frank Jiang said in a statement, adding that in addition to Taiwan, the company will submit an NDA for the same indication in mainland China in the first half of this year.