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

Background: 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. Methods: 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. Results: 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). Conclusions: 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.