On April 23, 2020 CStone Pharmaceuticals reported that the China National Medical Products Administration (NMPA) has accepted the New Drug Application (NDA) of the precision therapy avapritinib for two indications, one for the treatment of adults with unresectable or metastatic GIST harboring a platelet-derived growth factor receptor alpha (PDGFRA) exon 18 mutation, including PDGFRA D842V mutations; the other for the treatment of adults with unresectable or metastatic fourth-line GIST (Press release, CStone Pharmaceauticals, APR 23, 2020, View Source [SID1234556527]). Developed by CStone’s partner Blueprint Medicines, avapritinib is an investigational, orally available, potent and selective inhibitor of KIT and PDGFRA mutant kinases. This is the first time CStone has submitted an NDA to the NMPA and marks another milestone in the Company’s transition toward commercialization.

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

                  Schedule Your 30 min Free Demo!

With an annual incidence rate of 1-1.5 per 100,000, there are approximately 14,000 to 21,000 new cases of GIST in China every year1, and around 90% of these cases are associated with dysregulated cell growth due to mutations in KIT or PDGFRA tyrosine kinases. In January 2020, avapritinib was approved by the U.S. Food and Drug Administration (FDA) for the treatment of adults with unresectable or metastatic GIST harboring a PDGFRA exon 18 mutation, including PDGFRA D842V mutations, and became the first precision medicine approved for the treatment of GIST harboring a PDGFRA exon 18 mutation in the United States.

"In just three months after avapritinib was approved by the U.S. FDA, CStone has submitted NDAs for this drug candidate in Taiwan and mainland China, which we hope will soon make this first-in-class precision therapy candidate accessible to patients with advanced GIST in Greater China," said Dr. Frank Jiang, Chairman and CEO of CStone. "As CStone continues to accelerate its transition toward commercialization, we plan to submit several NDAs in China across multiple indications for our lead assets in the next few months."

"Avapritinib has demonstrated outstanding antitumor activity and a well-tolerated safety profile in advanced PDGFRA exon 18 mutant GIST and fourth-line GIST. Due to the very limited benefits from approved treatment options in these two groups of GIST patients, there is an urgent unmet clinical need for new therapies," said Lin Shen, M.D., Professor and Director of Department of Gastrointestinal Oncology, Vice President of Peking University Cancer Hospital and Institute, and the principal investigator for the bridging study of avapritinib in GIST in China. "As a physician, I hope avapritinib will soon be available in our clinical practice for the treatment of advanced GIST."

Results from the Phase I NAVIGATOR study of avapritinib in PDGFRA exon 18 mutant GIST and fourth-line GIST were presented at the Connective Tissue Oncology Society Annual Meeting in November 2019. As of the data cutoff date of November 16, 2018:

43 patients with PDGFRA exon 18 mutant GIST and 111 patients with fourth-line GIST were treated at a starting dose of 300 or 400 mg once daily and evaluable for response assessments.
In patients with PDGFRA Exon 18 mutant GIST, the overall response rate (ORR) was 86% with one response pending confirmation, and the median duration of response (DOR) was not reached.
In patients with fourth-line GIST, the ORR was 22% with one response pending confirmation, and the median DOR was 10.2 months.

The Phase I/II bridging study conducted by CStone in patients with advanced GIST in China has produced encouraging preliminary results demonstrating avapritinib was well-tolerated, and safety and pharmacokinetic profiles were consistent with those previously reported for the global NAVIGATOR study.

"The current treatment approach for GIST in China is mainly based on sequential tyrosine kinase inhibitors (TKIs), but the approved TKIs only offer limited efficacy2 in patients with PDGFRA D842V mutations. Moreover, Chinese patients with fourth-line GIST face challenges on multiple fronts, including drug-resistant mutations and a lack of effective treatment options," said Dr. Jason Yang, Chief Medical Officer of CStone. "I am pleased that 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."

CStone Pharmaceuticals and Blueprint Medicines have an exclusive collaboration and license agreement for the development and commercialization of avapritinib and certain other drug candidates in mainland China, Hong Kong, Macau and Taiwan. Blueprint Medicines retains development and commercial rights for these licensed products in the rest of the world.