FDA approves the first targeted therapy to treat a rare mutation in patients with gastrointestinal stromal tumors

FDA approved on Thursday avapritinib (Ayvakit—Blueprint Medicines) for the treatment of adults with unresectable or metastatic gastrointestinal stromal tumor (GIST) harboring a platelet-derived growth factor receptor alpha (PDGFRA) exon 18 mutation.

FDA approved on Thursday avapritinib (Ayvakit—Blueprint Medicines) for the treatment of adults with unresectable or metastatic gastrointestinal stromal tumor (GIST) harboring a platelet-derived growth factor receptor alpha (PDGFRA) exon 18 mutation. The approval includes GIST that includes a PDGFRA D842V mutation, the most common exon 18 mutation. "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," said Richard Pazdur, MD, director of FDA's Oncology Center of Excellence and acting director of the Office of Oncologic Diseases in the agency's Center for Drug Evaluation and Research. "Clinical trials showed a high response rate with almost 85% of patients experiencing tumor shrinkage with this targeted drug." FDA approved avapritinib, a kinase inhibitor, based on the findings from a clinical trial involving 43 patients with GIST harboring a PDGFRA exon 18 mutation. Common adverse effects for patients taking the drug included edema, nausea, fatigue/asthenia, cognitive impairment, vomiting, decreased appetite, diarrhea, hair color changes, increased lacrimation, abdominal pain, constipation, rash, and dizziness. FDA noted that avapritinib can cause intracranial hemorrhage and can also cause central nervous system effects, including cognitive impairment, dizziness, sleep disorders, mood disorders, speech disorders and hallucinations.