Comparison of sunitinib (su) versus temsirolimus (tem) in patients (pts) with poor-risk metastatic renal cell carcinoma (prmRCC)

539 Background: Based on a single phase 3 study, the mTOR inhibitor tem was approved as 1st line therapy for prmRCC. However, in daily practice, prmRCC pts are often treated with the VEGFR and PDGFR inhibitor su. We aimed to compare the clinical effectiveness of su vs tem in prmRCC pts. Methods: We performed an international multicenter retrospective study of pts with prmRCC (HENG criteria), who were treated in 8 centers across 2 different countries. 31 pts were treated with 1st line tem. Each tem treated pt was individually matched with a 1st line su treated pt, by clinicopathologic factors. The effect of tx type (tem vs su) on clinical benefit, progression free survival (PFS) and overall survival (OS), was tested using a chi-square test and partial likelihood test from cox model. Furthermore, univariate and multivariate analyses of association between clinicopathologic factors and tx type (tem vs su), and outcome were performed using the entire pt cohort (n=62). Results: The groups were matched by age (median 65), gender (male 68%), prior nephrectomy (58%), renal cell carcinoma histology (clear cell 81%), smoking status (active in 35%), use of angiotensin system inhibitors (42%), and pre-tx neutrophil to lymphocyte ratio >3 (58%). In tem vs su treated pts, clinical benefit (partial response + stable disease) was 61% (n=19) (partial response 6%, n=2) vs 71% (n=22) (partial response 29%, n=9) (p=0.62). Median PFS was 5 vs 8 mos (p=0.08), and median OS 9 vs 17 mos (p=0.03). In multivariate analyses of the entire pt cohort (n=62), su tx was independently associated with OS (HR 0.6, p=0.001). Conclusions: In prmRCC patient, the VEGFR inhibitor su may be associated with an improved outcome vs the mTOR inhibitor tem.