Abstract
OBJECTIVE: This prospective, post-marketing study collected sunitinib safety and efficacy data in Japanese patients with unresectable/metastatic renal cell carcinoma. Retrospective analysis investigated adverse events as potential sunitinib efficacy biomarkers. METHODS: Patients administered sunitinib, after its release, were registered until reaching a pre-specified number of cases. Primary starting dose was 50 mg/day orally on a 4-weeks-on and 2-weeks-off schedule. Physicians completed investigation forms at 6-week intervals for 24 weeks. Associations between baseline characteristics and adverse events were analyzed by Cox proportional hazards model and compared by χ(2) test. The log-rank test compared survival in subpopulations based on selected factors. RESULTS: Of note, 1689 patients receiving sunitinib were registered between June 2008 and November 2009. Most of them were males (75%), aged <65 years (56%), and had Eastern Cooperative Oncology Group performance status 0/1 (90%), metastatic disease (88%) and previous systemic therapy (66%). Grade ≥ 3 adverse events occurred in 70%, with reduced platelet count the most common (34%). Characteristics significantly associated with Grade ≥ 3 adverse events were female sex, age ≥ 55 years, Eastern Cooperative Oncology Group performance status ≥ 2, history of several medical conditions and prior treatment. Objective response rate was 22%. Median progression-free survival was 22.7 weeks. Median overall survival was not reached; however, 24-week overall survival rate was 84%. Improved overall survival was associated with higher relative dose intensity during the first 6 weeks and specific adverse events: hypertension, hand-foot syndrome, hypothyroidism, leukopenia and thrombocytopenia. CONCLUSIONS: Sunitinib demonstrated acceptable safety and useful efficacy in Japanese patients with unresectable/metastatic renal cell carcinoma. Potential biomarkers associated with greater efficacy were relative dose intensity and specific adverse events.