Prospective comparison of sorafenib and sunitinib for second-line treatment of cytokine-refractory kidney cancer patients.

OBJECTIVES: It was the aim of this study to investigate the clinical differences between the tyrosine kinase inhibitors (TKIs) sorafenib and sunitinib as second-line treatment for cytokine-refractory kidney cancer patients.

METHODS: Twenty consecutive patients received continuous treatment of oral sorafenib at a dose of 400 mg twice daily in 6-week cycles. Sunitinib was administered to the remaining 20 patients at 50 mg once daily in repeated 6-week cycles consisting of daily therapy for 4 weeks, followed by a 2-week off-treatment period. We correlated best treatment responses and progression-free survival (PFS) with either TKI treatment. Adverse events were evaluated and differences were compared between both treatment groups.

RESULTS: In the sorafenib group, 2 (10%) patients showed a partial response (PR) and 4 (20%) patients had progressive disease (PD) versus 6 (30%) PRs and 3 (15%) PDs in the sunitinib group, respectively (p = 0.195). The median PFS was 6.4 months for sorafenib and 7.4 months for sunitinib (p = 0.969). In contrast to gender, age and the number of prior cytokine therapy cycles, the Eastern Cooperative Oncology Group performance status (p = 0.024) and the Memorial Sloan-Kettering Cancer Center risk groups for second-line treatments (p = 0.015) were independent predictive parameters of PFS. Gastrointestinal symptoms were found to occur with greater frequency in the sunitinib group (p = 0.03).

CONCLUSIONS: Both TKIs showed comparable clinical benefits. The Eastern Cooperative Oncology Group performance status and the Memorial Sloan-Kettering Cancer Center risk groups can help determine which patients might benefit from alternative drug treatments.