Efficacy and Safety of Regorafenib in Korean Patients with Advanced Gastrointestinal Stromal Tumor after Failure of Imatinib and Sunitinib: A Multicenter Study Based on the Management Access Program

PURPOSE The aim of this study was to confirm the efficacy and safety of regorafenib for advanced gastrointestinal stromal tumors (GISTs) reported in the GRID phase III trial in Korean patients. MATERIALS AND METHODS Fifty-seven Korean patientswith advanced GISTwho experienced both imatinib and sunitinib failure were enrolled in the management access program between December 2012 and November 2013 and treated with regorafenib (160 mg orally once daily in a 3 weeks on/1 week off). RESULTS None of the patients achieved a complete or partial response while 25 patients (44%) showed stable disease for ≥ 12 weeks. With a median follow-up of 12.7 months (range, 0.2 to 27.6 months), the median progression-free survival and overall survival were 4.5 months (95% confidence interval [CI], 3.8 to 5.3) and 12.9 months (95% CI, 8.1 to 17.7), respectively. Interestingly, 15 patients (26%) experienced an exacerbation of their cancer-related symptoms (abdominal pain in eight and abdominal distension in five) during the rest period for regorafenib, but all were ameliorated upon the resumption of regorafenib. The most common grade 3 or 4 adverse event was a hand-foot skin reaction (25%). The regorafenib dose was reduced in 44 patients (77%) due to toxicity, which manifested mainly as a hand-foot skin reaction (n=31). CONCLUSION This study confirmed the efficacy and safety of regorafenib for advanced GIST after imatinib and sunitinib failure in Korean patients. Considering the exacerbation of the cancer-related symptoms observed during the rest periods, further exploration of the continuous dosing schedule of regorafenib is warranted in future clinical trials.