Avapritinib in advanced gastrointestinal stromal tumor: case series and review of the literature from a tertiary care center in India

The therapeutic landscape in advanced gastrointestinal stromal tumor has evolved. Avapritinib and ripretinib have now been approved by the US FDA for platelet-derived growth factor alpha D842V-mutant and refractory gastrointestinal stromal tumor patients, respectively. Here we report five patients who have been on avapritinib under an expanded access program. Response assessment was available for four patients – a partial response in two patients and stable disease in one, while one patient had progressive disease. Though preliminary results of the VOYAGER trial have shown less activity of avapritinib and no significant difference in progression-free survival when compared with regorafenib, avapritinib may show some clinical benefit in a subset of patients refractory to approved therapies. We share our experience of five cases, with clinical benefit in three. We believe avapritinib should be further evaluated in clinical trials. The new therapeutic options, avapritinib and ripretinib, alongside the molecular landscape of driver mutations in gastrointestinal stromal tumor present an opportunity for personalized treatment. We report five cases of advanced and refractory gastrointestinal stromal tumor who received avapritinib under an expanded access program. Two patients had a partial response; one each had a stable and progressive disease. Response was not available for one patient. In the VOYAGER trial, avapritinib failed the primary end point but showed clinical activity and hence avapritinib merits further evaluation. Our experience with avapritinib supports further testing of this drug.