Efficacy of Cabozantinib in Patients With Advanced Renal Cell Carcinoma With Bone Metastasis Assessed by Modified MD Anderson Criteria: An Open-Label Phase 2 Study.

OBJECTIVES

Cabozantinib treatment is associated with improved survival in renal cell carcinoma (RCC) patients with bone metastasis. We evaluated the direct effects of cabozantinib on bone metastasis in advanced RCC (aRCC).

METHODS

In this multicenter, open-label study, adult Japanese aRCC patients with bone metastasis received oral cabozantinib 60 mg once daily until drug discontinuation/data cut-off. The primary endpoint was the objective response rate (ORR) of bone target lesions (modified MD Anderson criteria) evaluated by an independent radiology committee. Secondary endpoints were overall survival (OS), disease control rate (DCR) of bone lesions, progression-free survival (PFS), symptomatic skeletal events (SSEs), bone-specific PFS, and safety. Exploratory endpoints were changes in bone turnover, plasma biomarkers, and health-related quality of life (HRQoL).

RESULTS

Thirty-one patients were enrolled (median age, 70.0 years; 64.5% men). The ORR of bone target lesions was 6.5% (90% CI 1.2-18.9), DCR was 90.3% (90% CI 76.8-97.3), and the median change in bone target lesion size was -5.2% (range-42.8 to 19.2). Median PFS was 11.9 months (95% CI 5.7-not evaluable), median OS was 24.9 months (95% CI 19.1-not evaluable), and three patients reported SSEs. Bone-specific PFS remained > 60% among patients who were evaluable during follow-up. Levels of bone-turnover markers generally decreased; no trends were observed in plasma biomarkers. EQ-5D-5L index values remained generally stable. Common adverse events were palmar-plantar erythrodysesthesia syndrome (54.8%), malaise (45.2%), diarrhea, abnormal hepatic function (32.3%), and hypertension (32.3%).

CONCLUSIONS

Most aRCC patients showed favorable disease control following cabozantinib treatment. No new safety issues were observed.

TRIAL REGISTRATION: Japan Registry of Clinical Trials (JRCT), registration no. jRCTs031210220.