Treatment of regorafenib in patients with metastatic or unresectable gastrointestinal stromal tumor after failure of imatinib and sunitinib

Imatinib mesylate has dramatically improved the survival with unresectable or metastatic GIST, whereas many patients subsequently develop imatinib resistance. Followed by sunitinib, regorafenib has been approved since 2013 in Japan. We aimed to assess efficacy and safety of regorafenib in GIST patients in clinical setting. The study was conducted between August 2013 and April 2016, among 11 patients with GIST treated by regorafenib. The median treatment duration was 8.4 months. The median progression-free survival (PFS) was 7.4 months. Nine patients experienced at least one Grade 3 or 4 toxicity from regorafenib. The most common Grade 3 toxicity was hand-and-foot skin reactions (4 of 11; 36.4%), followed by hypertension (3 of 11; 27.3%). Dose reduction was required in 8 patients. Although dose modifications due to toxicities were very common, some patients achieved long PFS with regorafenib treatment.