US-based biopharmaceutical company Exelixis has demonstrated improvement in progression-free survival (PFS) with cabozantinib compared to sunitinib in patients with advanced intermediate or poor risk renal cell carcinoma (RCC) during Phase ll trial CABOSUN.
Sunitinib is an oral, small-molecule, multi-targeted receptor tyrosine kinase (RTK) inhibitor that was approved by the US Food and Drug Administration (FDA) to treat RCC, which is a type of kidney cancer.
CABOSUN is a randomised, open-label, active-controlled Phase ll trial that enrolled 150 patients with advanced RCC who were not treated previously.
During the trial, patients were randomised 1:1 to receive 60mg of cabozantinib once daily or 50mg of sunitinib once per day, four weeks on followed by two weeks off.
The trial’s primary endpoint is achieving PFS, which is defined as time from randomisation to disease progression or death, whichever occurs first.
CABOSUN’s secondary endpoints included overall survival and objective response rate.
The safety data in the cabozantinib-treated arm of the trial were found to be consistent with those observed in previous trials in patients with advanced RCC.
The Alliance for Clinical Trials in Oncology under Exelixis’ partnership with US’s National Cancer Institute’s Cancer Therapy Evaluation Programme (NCI-CTEP) is carrying out the Phase II trial.
CABOSUN study chair and Dana-Farber Cancer Institute’s Lank Centre for Genitourinary Oncology clinical director Dr Toni Choueiri said: "The positive outcome of CABOSUN is extremely exciting, as it marks the very first time that a therapy has shown a progression-free survival benefit compared to standard of care first-line treatment sunitinib for patients with previously untreated advanced renal cell carcinoma.
"Based on these findings, cabozantinib may have the potential to become a new gold standard for previously untreated patients following their diagnosis with advanced kidney cancer."
Exelixis is currently working with clinical advisors on the development plan for cabozantinib in future clinical trials to treat other genitourinary malignancies.