NEW YORK – CStone Pharmaceuticals said on Thursday that its new drug application of avapritinib (Ayvakit) for PDGFRA exon 18-mutated metastatic or unresectable gastrointestinal stromal tumors was accepted by China's National Medical Products Administration.
Avapritinib is an inhibitor of KIT and PDGFRA mutant kinases that was developed by Blueprint Medicines. The drug is already approved in the US for the treatment of GIST patients with PDGFRA exon 18 mutations.
Suzhou, China-based CStone and Blueprint have an exclusive collaboration and licensing agreement for the development and commercialization of the drug in Mainland China, Hong Kong, Macau, and Taiwan. In late March, CStone submitted avapritinib for approval to the Taiwan Food and Drug Administration in the same molecularly defined indication.
Results from the Phase I NAVIGATOR trial supported the drug's application in China. The data showed that patients with PDGFRA exon 18-mutated GIST had an overall response rate of 86 percent. As of the data cutoff in November 2018, the median duration of response was not reached in this group.
"The current treatment approach for GIST in China is mainly based on sequential tyrosine kinase inhibitors, but the approved TKIs only offer limited efficacy in patients with PDGFRA D842V mutations," CStone CMO Jason Yang said in a statement. "The bridging study in China has yielded results consistent with those from the global NAVIGATOR study, and I hope patients with advanced GIST who are in urgent need for new treatment options will benefit from this precision therapy in the near future."
Around 90 percent of GIST patients have mutations in KIT and PDGFRA, and most GIST patients don't respond to chemotherapy and radiotherapy.