The Food and Drug Administration has approved avapritinib (Ayvakit) for the treatment of adults with unresectable or metastatic gastrointestinal stromal tumors (GIST) with a platelet-derived growth factor receptor–alpha (PDGFRA) exon 18 mutation.
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Approval was based on results from a clinical trial of 43 patients with PDGFRA exon 18 mutations, including 38 patients with a PDGFRA D842V mutation, who received 300 mg avapritinib once daily, the FDA said in a statement.
The overall response rate was 84% (7% with complete response, 77% with partial response); the response rate in patients with a D842V mutation was 89% (8% with complete response, 82% with partial response). Median response duration was not reached, but 61% of patients had a response lasting longer than 6 months.
The most common adverse events associated with avapritinib include edema, nausea, fatigue/asthenia, cognitive impairment, vomiting, decreased appetite, diarrhea, hair color changes, increased lacrimation, abdominal pain, constipation, rash, and dizziness. The drug also can cause intracranial hemorrhage and have effects on the central nervous system.
“GIST harboring a PDGFRA exon 18 mutation do not respond to standard therapies for GIST. However, today’s approval provides patients with the first drug specifically approved for GIST harboring this mutation,” Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Oncologic Diseases in the Center for Drug Evaluation and Research, said in the statement.