Cabozantinib versus sunitinib for previously untreated patients with advanced renal cell carcinoma (RCC) of intermediate or poor risk: Subgroup analysis of progression-free survival (PFS) and objective response rate (ORR) in the Alliance A031203 CABOSUN trial.

Abstract

582 Background: The randomized phase 2 CABOSUN trial (NCT01835158) compared cabozantinib (C) with sunitinib (S) as initial systemic therapy in patients (pts) with RCC of intermediate or poor risk. Compared with S, C improved both PFS and ORR as assessed by independent radiology review committee (IRC). Median PFS per IRC was 8.6 mo for C vs 5.3 mo for S (HR 0.48, 95% CI 0.31-0.74 two-sided p = 0.0008), and ORR per IRC was 20% vs 9%. Methods: 157 patients were randomized 1:1 to receive C (60 mg qd) or S (50 mg qd, 4 weeks on/2 weeks off) stratified by International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk group and the presence of bone metastases. Subgroup analyses of PFS per IRC and ORR per IRC are presented based on stratification factors, age, sex, baseline ECOG status, and MET tumor expression by immunohistochemistry. The primary endpoint was investigator-assessed PFS. PFS and ORR were evaluated by IRC in a post-hoc analysis. Results: 45% of pts were ≥65 years, 78% were male, 54% were ECOG 1 or 2, 19% were poor risk, and 36% had bone metastases. MET status was determined in 131 pts; of these 47% were MET positive. The HR for PFS per IRC favored C over S across all subgroups analyzed (Table). Subgroups with poor prognostic characteristics (poor risk, ECOG 1 or 2, presence of bone metastases) had shorter median PFS for both C and S. Odds ratios for ORR also favored C over S, with the highest C ORR in the MET positive subgroup (34% C vs 10% S). Conclusions: C was associated with improved PFS and ORR compared with S in previously untreated pts with advanced RCC irrespective of baseline characteristics. Clinical trial information: NCT01835158. [Table: see text]