Phase IV Study of Sunitinib in Chinese Patients with Imatinib-Resistant or Imatinib-Intolerant Gastrointestinal Stromal Tumors

Abstract

Introduction Sunitinib is approved in China for treatment of gastrointestinal stromal tumors (GIST), after disease progression on, or intolerance to, imatinib. However, available data from prospective clinical trials on its efficacy and safety in Chinese patients is limited. Our objective is to determine the efficacy and safety of sunitinib in Chinese patients with imatinib-resistant/intolerant GIST. Methods An open-label, single-arm, multicenter, phase IV study was performed in Chinese patients with imatinib-resistant/intolerant GIST. Sunitinib was administered orally in 6-week cycles of 4 weeks on-treatment (50 mg once daily) and 2 weeks off-treatment. The primary endpoint was progression-free survival (PFS). Tumors were assessed every 6 weeks for the first 24 weeks and every 12 weeks thereafter. Responses were evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.0. Results A total of 60 patients were enrolled, of whom 59 were treated with sunitinib. All patients were Asian, and mean age was 55.1 years. Median PFS was 46.4 weeks (95% CI 33.6–53.1). An objective response (complete or partial) was observed in 11/58 (19%) patients. Median overall survival was 111.3 weeks (95% CI 75.4–167.1), median time to tumor progression was 47.3 weeks (95% CI 34.1–59.3), and median time to tumor response was 22.6 weeks (95% CI 10.4–57.3). The most common adverse events included leukopenia, fatigue, hand-foot syndrome, and neutropenia. No new safety concerns were identified. Conclusions This study confirms that sunitinib is active and well tolerated in Chinese patients with imatinib-resistant/intolerant GIST. ClinicalTrials.gov identifier NCT00793871. Funding Pfizer Inc, USA.