Retrospective analyses of patient characteristics having predictive impact on survival under everolimus

Everolimus is the standard second-line therapy for patients with metastatic renal cell carcinoma (mRCC). We evaluated whether the response to first-line therapy with a tyrosine kinase inhibitor (TKI) has predictive impact on the progression-free survival (PFS) and overall survival (OS) under everolimus. In addition, patient characteristics were evaluated for their predictive impact on the response under everolimus.

42 patients with mRCC treated with everolimus (RAD001) within a clinical trial were analyzed. Prior to everolimus, every patient had received at least 1 TKI therapy. Another TKI for second line was given to 15 patients. PFS and OS were estimated according to the Kaplan-Meier method and compared with the log-rank test.

Median PFS during everolimus therapy was 5.2 months (range 1.3-17.8). 27 patients (64%) achieved stable disease (SD) or partial remission (PR). Patients with a beneficial PFS under first-line TKI achieved a better OS after start of everolimus treatment (p = 0.05) and so did TKI responders (p = 0.04). A reduced OS was associated with liver metastases (p = 0.04) and high tumor burden (p = 0.01).

A beneficial outcome under prior TKI therapy is predictive for a superior survival in patients treated with everolimus, while high tumor burden and liver metastases impair the OS.