Purpose: Sunitinib and sorafenib are novel tyrosine kinase inhibitors (TKIs) that have shown significant clinical activity in metastatic clear cell renal cell carcinoma (RCC). The activity of sunitinib and sorafenib in non-clear cell histologies has not been evaluated.
Patients and methods: Clinical features at study entry and treatment outcomes were evaluated in patients with metastatic papillary RCC (PRCC) and chromophobe RCC (ChRCC) who received either sunitinib or sorafenib as their initial TKI treatment in five US and French institutions. Response rate and survival were documented. Fisher's exact test was used for categoric variables, and the Kaplan-Meier method was used to estimate survival.
Results: Fifty-three patients were included. The number of patients with papillary and chromophobe histologies was 41 (77%) and 12 (23%), respectively. Response rate, progression-free survival (PFS) time, and overall survival time for the entire cohort were 10%, 8.6 months, and 19.6 months, respectively. Three (25%) of 12 ChRCC patients achieved a response (two patients treated with sorafenib and one treated with sunitinib), and PFS was 10.6 months. Two (4.8%) of 41 PRCC patients achieved a response (both patients were treated with sunitinib). PFS for the whole cohort was 7.6 months. Sunitinib-treated PRCC patients had a PFS of 11.9 months compared with 5.1 months for sorafenib-treated patients (P < .001).
Conclusion: Patients with PRCC and ChRCC may have prolonged PFS from sunitinib and sorafenib, although clinical responses remain overall low in PRCC. Additional prospective trials with these agents in non-clear cell RCC will further clarify their use in the future.