- To assess clinical benefit of ponatinib in patients with KIT or PDGFRA mutant GIST defined as clinical benefit rate (CBR), which is the composite of complete response (CR), partial response (PR) and stable disease (SD) at ≥16 weeks after start of treatment per modified response evaluation criteria in solid tumors (modified RECIST 1.1 [Demetri et al., 2013]) as a measure of disease control