Overall survival and good tolerability of long-term use of sorafenib after cytokine treatment: final results of a phase II trial of sorafenib in Japanese patients with metastatic renal cell carcinoma.

Unlabelled: What's known on the subject? and What does the study add? Interim result of this study had shown promising efficacy, with response rate of 14.7% and median PFS of 7.4 months, and good tolerability of sorafenib in previously-treated Japanese patients with metastatic RCC. Final result of the study adds: (1) the median overall survival of 25.3 months, which is longer than that in the global phase III study TARGET; (2) the response rate which elevated to 19.4% because of 6 late responders achieved after 9.2 months or longer of SD period; (3) lack of either unknown adverse events nor cumulative toxicity in the long-term use of sorafenib.

Objective: • To explore the long-term efficacy and safety of sorafenib in Japanese patients with metastatic renal cell carcinoma (RCC) in a phase II trial.

Patients And Methods: • In all, 131 Japanese patients with metastatic RCC who had received nephrectomy and failed at least one cytokine-containing systemic therapy received continuous sorafenib 400 mg twice daily, and the efficacy and safety parameters were evaluated in these patients, including objective response rate, progression-free survival and overall survival.

Results: • Of the total, 129 patients were valid for intention-to-treat analyses and 131 patients were valid for safety analyses. • Twenty-five patients (19.4%) had confirmed partial response and 87 patients (67.4%) had stable disease as best overall response. The 25 patients included six late-responders who achieved response after 9.2 months or longer of stable disease. The objective response rate and disease control rate were 19.4% and 73.6%, respectively. • The median overall survival and median progression-free survival were 25.3 and 7.9 months, respectively. • Safety profile was consistent with those previously reported, with hand-foot skin reaction (58.0%), lipase elevation (57.3%) and diarrhoea (42.7%) as the most frequently observed drug-related adverse events. Neither unknown adverse event nor cumulative toxicity was observed over the long-term use of sorafenib. • Despite the dose discontinuation/interruption/reduction, the mean and median relative dose intensities were 86.4% and 97.4%, respectively.

Conclusion: • The final results of this trial showed that long-term use of sorafenib after cytokine treatment was well tolerated and provided new efficacy data, including late-response events and favourable overall survival in Japanese patients with metastatic RCC.