Efficacy and safety of regorafenib in Japanese patients with advanced gastrointestinal stromal tumors.

Background: Regorafenib is an oral multi-kinase inhibitor that has been established as third-line treatment for patients after the failure of imatinib and sunitinib. However, since clinical data of regorafenib in the Japanese population are still lacking, the management of regorafenib is mainly based on the clinical experience of each oncologist. The aim of this study was to evaluate the efficacy and safety of regorafenib in a Japanese population.

Methods: Thirty-three patients treated with regorafenib for metastatic and recurrent gastrointestinal stromal tumors were retrospectively enrolled. This study investigated the anti-tumor effect, including overall survival, progression-free survival, and safety, which was evaluated based on the incidence of adverse events.

Results: The median overall survival of patients treated with regorafenib was 23.8 months and the 1-year overall survival rate was 80.0%, the median progression-free survival was 7.1 months and the 1-year progression-free survival rate was 40.2%. The responses to regorafenib were partial response in 3 cases (9.1%), stable disease in 17 (51.5%), progressive disease in 10 (30.3%), and non-evaluable in 3 (9.1%). The disease control rate was 54.0%. Treatment-related adverse events were reported in all patients, with the most common being hand-foot syndrome (72.7%), followed by liver damage (36.4%) and diarrhea (27.3%), and six patients (20.0%) were discontinued due to adverse events.

Conclusion: This is the first report of Japanese patients with gastrointestinal stromal tumors treated with regorafenib. Regorafenib showed efficacy and a manageable safety profile in Japanese patients with advanced gastrointestinal stromal tumors, which was comparable with previous studies.