New Drug Outperforms Standard Treatment for Kidney Cancer

A newly-approved kidney cancer drug was seen to outperform the first-line treatment for the disease in a phase 2 clinical trial.

Patients with metastatic kidney cancer taking cabozantinib had a longer time to progression compared with patients taking sunitinib (Sutent), a drug that has been the first-line treatment for the disease for a decade.

Trial data also showed that treatment with cabozantinib decreased the mortality risk by 20%, according to a study published by the Journal of Clinical Oncology.

“These results are very relevant to our practice and our kidney cancer patients -- they may change the standard,” said lead author Toni K. Choueiri. “The results also demonstrate that studies sponsored by the National Cancer Institute can accrue rapidly and yield highly relevant results to the field.”

Metastatic clear cell renal cell carcinoma is typically incurable, and can affect multiple organs. The investigators identified factors that classify patients as good, intermediate, or poor risk regarding their prospective treatment outcomes.

The study included 157 patients with metastatic disease. Of the treatment-naïve patients, 81% were considered to be intermediate risk, and 19% were poor risk. In 36% of the patients included in the trial, the cancer had metastasized to the bone, which is a contributing factor to a poor outcome.

Currently, the most effective treatment options for patients with metastatic kidney cancer target vascular endothelial growth factor (VEGF) and its receptors. These drugs are able to inhibit blood supply to the tumors in order to slow their growth or shrink them.

Both sunitinib and cabozantinib are VEGF inhibitors, and cabozantinib also blocks MET and AXL oncogenes that are involved in resistance to this class of drugs.

The clinical trial, A031203 CABOSUN, is comparing cabozantinib versus sunitinib as a first-line treatment for these patients. Cabozantinib recently received approval in the United States earlier this year as a second-line treatment for patients with advanced kidney cancer.

The primary endpoint of the trial is progression-free survival, which was an average of 8.2 months for patients taking cabozantinib, and 5.6 months for those taking sunitinib. Cabozantinib also reduced disease progression or death by 34% compared with sunitinib, the investigators reported.

They also discovered that 46% of patients taking cabozantinib had a complete or partial response to the treatment, compared with 18% of those taking sunitinib.

Preliminary findings suggest that cabozantinib was associated with a 20% decrease in mortality risk, according to the study. The safety profiles of both drugs were comparable to other VEGF inhibitors.

These findings suggest that cabozantinib may provide a superior first-line treatment option for patients with metastatic kidney cancer, and may improve survival among these patients.