Comparing cabozantinib (C) treatment for a cohort of patients with metastatic clear cell (ccRCC) and variant histology renal cell carcinoma (vhRCC): A retrospective study.

Abstract

702 Background: Both the randomized METEOR and CABOSUN studies in ccRCC found substantial benefit for patients receiving (C). We have previously reported (C) to have significant activity in vhRCC. To date no comparative data exists in evaluating the utility of (C) in ccRCC and vhRCC. Methods: This is a retrospective study of patients with ccRCC and vhRCC who received (C) at a single center from 1/2014-9/2017. Data tabulated included baseline characteristics, toxicity, dose reductions, time on (C) and survival data. A blinded radiologist assessed the radiographic response using RECIST v1.1. Cox regression analysis of time to treatment failure (TTF) in ccRCC and vhRCC was performed, adjusting for age, gender, IMDC score, neutrophil to lymphocyte ratio (NLR), prior TKI treatment, and number of metastatic sites. Statistical analysis were performed using SPSS 23.0. Results:Time to treatment failure was significantly longer in vhRCC compared with ccRCC (16.1 vs 7.64 months, HR 0.42, 95%CI 0.22-0.79, p = 0.007). This difference persisted in the adjusted Cox regression model (HR 0.36, 95% CI 0.15-0.85, p = 0.02). Conclusions: In this retrospective comparative analysis of C treated vhRCC and ccRCC patients, C was found to have substantial activity in both cohorts of patients. The IMDC score was important to predict outcome. Both heavily pretreated patients with ccRCC and those with vhRCC appeared to have substantial benefit.[Table: see text]