Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the GI tract. The second most common type of GIST is driven by oncogenic mutations in PDGFRA, of which there are 50+ different kinase domain mutations reported. 82% of these occur in the kinase activation loop (AL), with the majority being a single point mutation, D842V. PDGFRA-D842V is notoriously resistant to conventional tyrosine kinase inhibitors approved for GIST, including imatinib. However, it isn't known how GIST with other PDGFRA AL mutations, which include numerous complex indels, would clinically respond to imatinib.