CaboPoint: a Phase II study of cabozantinib as second-line treatment in patients with metastatic renal cell carcinoma

Cabozantinib is an inhibitor of multiple tyrosine kinases, including AXL, MET and VEGF receptors. Here, we describe the rationale and design for the Phase II CaboPoint trial (ClinicalTrials.gov identifier: NCT03945773), which will evaluate the efficacy and safety of cabozantinib as a second-line treatment in patients with unresectable, locally advanced or metastatic renal cell carcinoma whose disease has progressed despite checkpoint inhibitor therapy. Patients will be recruited into two cohorts: prior ipilimumab plus nivolumab (cohort A) or prior checkpoint inhibitor-VEGF-targeted therapy (cohort B). All patients will receive once-daily oral cabozantinib 60 mg for up to 18 months. The primary end point is objective response rate. Secondary end points include overall survival, progression-free survival and safety. Lay abstract: Most patients diagnosed with kidney cancer have a type of tumor called renal cell carcinoma (RCC). Most cases of RCC are described as 'clear cell' because the tumor cells appear clear when viewed under a microscope. Cabozantinib is an oral treatment approved for use in some patients with advanced RCC, including those with clear cell disease. Cabozantinib slows RCC progression by targeting pathways that help tumors grow, including inhibition of VEGF. The ongoing CaboPoint study will assess the efficacy and safety of cabozantinib in patients with clear cell RCC that has progressed despite previous anticancer treatment involving an immune checkpoint inhibitor (CPI). CPI therapy helps the body to detect tumors and to launch its own anticancer response. Patients included in CaboPoint must be adults with clear cell RCC that is not suitable for surgery and has either spread within the kidney or to other organs, despite previous CPI-based therapy. In total, 250 patients will be recruited: 125 who received previous combination CPI treatment (ipilimumab plus nivolumab; Group A) and 125 who received previous CPI treatment plus anti-VEGF therapy (Group B). Patients will start cabozantinib at a dose of 60 mg/day and continue treatment for up to 18 months. The main outcome to be studied will be the number of patients with a reduction in tumor size (objective response rate). The length of time patients live with their disease, the effect of treatment on symptoms and patient safety will also be evaluated.