Avapritinib for the Treatment of CKIT or PDGFRA Mutation-Positive Locally Advanced or Metastatic Malignant Solid Tumors

This study tests avapritinib — a targeted drug — in people with advanced or metastatic solid tumors that carry specific genetic mutations in genes called CKIT or PDGFRA. These mutations are found in various cancers including melanoma, breast cancer, lung cancer, and others. Participants may be 12 years or older. **You may be eligible if...** - You are 12 years or older - You have a locally advanced or metastatic solid tumor with a CKIT or PDGFRA gene mutation - You have already received appropriate standard treatments that didn't work or aren't available - You are in reasonably good health overall **You may NOT be eligible if...** - Your cancer does not have a CKIT or PDGFRA mutation - You have not yet tried available standard therapies - You have significant heart, liver, or kidney problems Talk to your doctor to see if this trial is right for you.