Overall Survival and Updated Results from a Phase II Study of Sunitinib in Japanese Patients with Metastatic Renal Cell Carcinoma

BACKGROUND: In a phase II, open-label, multicentre Japanese study, sunitinib demonstrated antitumour activity and acceptable tolerability in metastatic renal cell carcinoma patients. Final survival analyses and updated results are reported. METHODS: Fifty-one Japanese patients with a clear-cell component of metastatic renal cell carcinoma (25 treatment-naïve; 26 cytokine-refractory) received sunitinib 50 mg orally, once daily (Schedule 4/2). Overall and progression-free survivals were estimated by the Kaplan-Meier method. Objective response rate (per Response Evaluation Criteria in Solid Tumours) and safety were assessed with an updated follow-up. RESULTS: First-line and pretreated patients received a median 6.0 and 9.5 treatment cycles, respectively. Investigator-assessed, end-of-study objective response rate was 52.0, 53.8 and 52.9% in first-line, pretreated and overall intent-to-treat populations, respectively. The median progression-free survival was 12.2 and 10.6 months in first-line and pretreated patients, respectively. Fourteen patients per group died (56 and 54%), and the median overall survival was 33.1 and 32.5 months, respectively. The most common treatment-related Grade 3 or 4 adverse events and laboratory abnormalities were fatigue (24%), hand-foot syndrome (18%), decreased platelet count (55%), decreased neutrophil count (53%) and increased lipase (49%). No Grade 5 treatment-related adverse events occurred. Forty patients (78%) required dose reduction, and 13 (25%) discontinued, due to treatment-related adverse events. CONCLUSIONS: With the median overall survival benefit exceeding 2.5 years, and acceptable tolerability, in first-line and pretreated Japanese metastatic renal cell carcinoma patients with Eastern Cooperative Oncology Group performance status 0/1, sunitinib showed a favourable risk/benefit profile, similar to Western studies. However, there was a trend towards greater efficacy and more haematological adverse events in Japanese patients.