Targeted Treatment for Gastrointestinal Stromal Tumors
The FDA has approved a molecularly targeted treatment for certain patients with this form of soft tissue sarcoma.
The U.S. Food and Drug Administration has approved a new treatment for certain patients with gastrointestinal stromal tumor (GIST), a common form of soft tissue sarcoma. On January 9, 2020, the FDA approved avapritinib (Ayvakit) for treating certain patients with gastrointestinal stromal tumor (GIST).
GISTs can arise anywhere along the gastrointestinal tract but most commonly in the stomach or small intestine. Most cases of GIST are fueled by mutations in either the KIT gene or the PDGFRA gene. According to the National Cancer Institute, there are around 3,300 to 6,000 new GIST cases per year in the United States.
While GISTs driven by most KIT and many PDGFRA mutations are responsive to treatment with the molecularly targeted therapeutic imatinib (Gleevec), those caused by mutations in a region of the PDGFRA gene called exon 18 mutation are not responsive to imatinib. That finding was highlighted in research published in the Clinical Cancer Research, a journal of the American Association for Cancer Research (AACR).
Avapritinib is a molecularly targeted therapeutic that can block the effects of PDGFRA exon 18 mutations. It was approved specifically for treating adults with unresectable or metastatic GISTs fueled by a PDGFRA exon 18 mutation, including D842V mutations.
As noted in a recent Clinical Cancer Research paper, avapritinib is being tested in several other clinical trials as a treatment for a wider array of GISTs and other types of cancer, so we will likely hear more about this molecularly targeted therapeutic in the future.