AUSTIN, Texas, Sept. 26 (UPI) -- A pair of drugs have overshadowed the use of standard therapies after new clinical trials suggest they work better for advanced kidney cancer.
The two treatments -- nivolumab and cabozantinib -- each successfully prolonged the survival of renal-cell cancer patients during separate studies both published in the New England Journal of Medicine.
Nivolumab, an existing drug sold as Opdivo, resulted in a 27 percent decreased risk of death during a clinical trial involving 821 patients in an advanced stage of kidney cancer. The therapy belongs to a group of drugs called immune checkpoint inhibitors, which enhance the body's natural defenses against cancer cells. Under the name Opdivo, the drug is already used to treat lung cancer and advanced skin cancer.
The nivolumab study was reportedly halted before its scheduled completion due to its overwhelming effectiveness in prolonging patients' lives and its much higher tumor response rate. Patients given the standard treatment, everolimus, were then treated with novolumab instead for ethical reasons. Compared to the standard survival rate of 19.6 months with everolimus, patients treated with nivolumab during the clinical trials experienced a rate increase to 25 months.
The second drug, cabozantinib, was also tested against everolimus. While nivolumab was tested for overall survival, cabozantinib was tested for length of survival without progression of the cancer. It too proved more successful against the disease and resulted in a 42 percent decrease in patients' risk of progression or death. Cabozantinib belongs to another group of drugs -- tyrosine kinase inhibitors -- which block the growth of cancer cells and tumors. Cabozantinib is sold as Cometriq and is generally used for the treatment of thyroid cancer.
The trial involved a smaller group of 658 renal-cell cancer patients and half were treated with cabozantinib. Researchers concluded cabozantinib increased patients' average survival rate from 3.8 months with the standard drug everolimus to 7.4 months.
According to an editorial published in New England Journal of Medicine, the benefits of the newly tested drugs compared to the standard therapy is "unequivocal," but pose new questions regarding their long-term effectiveness. The percentage of patients who reached complete remission were extremely low -- for cabozantinib, 0 percent of patients reached full remission; for nivolumab, 1 percent did.
Because of the low rates, and lack of effectiveness in curing the disease, the Journal says more experiments need to be done in terms of combining the drugs with pre-existing kidney cancer treatments.
"We have two new drugs that are very promising, and this is not a small increment," Dr. Toni K. Choueri, an oncologist who worked on both studies, told the New York Times.
"Maybe they're not curative, but patients will likely live longer and be around for their families and have more options, with the goal always, of course, the cure," he said. "Maybe the goal for now is to keep people around long enough to find the cure."
