(HealthDay) -- Long-term medication side effects such as fatigue can be key for patients deciding which cancer drug to take, new research suggests.
In the study, people with advanced kidney cancer preferred pazopanib (Votrient) over sunitinib (Sutent), according to a randomized controlled trial funded by the makers of pazopanib.
Although doctors may not see a big difference between the two U.S. Food and Drug Administration-approved drugs for the long-term treatment of kidney cancer that has metastasized (spread to other organs), researchers from France found that patients felt Votrient left them less fatigued and with a better quality of life, according to the study.
"While we expected patients would prefer one drug over the other, due to the known toxicity profiles, we didn't expect this great a preference," lead study author Dr. Bernard Escudier, a physician at the Institut Gustave Roussy, said in a news release. "This is an excellent method to report the way patients are feeling about the toxicity of drugs. It's an important reminder that low-grade toxicities patients experience may not seem bad, but if you are experiencing the toxicity over a long time, it has an effect on your quality of life."
Typically, reports of adverse events associated with drugs don't include how patients feel overall when they take a drug over many months, he added.
In the study, researchers randomly assigned 168 patients with metastatic kidney cancer to receive either Votrient or Sutent for 10 weeks. After a two-week break, the prescriptions were reversed for another 10 weeks. Neither patients nor physicians knew who was getting which drug.
About 70 percent of patients preferred Votrient, while 22 percent of patients chose Sutent and 8 percent had no preference.
About 60 percent of physicians preferred Votrient, while 21 percent opted for Sutent and 21 percent had no preference. Researchers said that physicians may not be placing as much significance on quality of life differences between the two drugs.
GlaxoSmithKline, the company that makes Votrient, funded the study, which was expected to be presented Saturday at the American Society of Clinical Oncology annual meeting, in Chicago.
Pfizer, the maker of Sutent, issued a statement on the findings on Friday.
"It is important to consider the limitations of this trial design," the drug maker said. The study involved a "small randomized phase 2 trial [and] was based on patient perceived tolerability without complete evaluation of efficacy, a key consideration in the treatment of metastatic cancer patients. Therefore, one cannot establish a full understanding of the comparative risk/benefit profile of SutentR (sunitinib malate) from this study," Pfizer said.
The company also noted that, "through experience in clinical practice and trials, physicians are continuously learning how to optimize the treatment of advanced [kidney cancer] to improve the management of this devastating disease and ensure patients continue to get maximum benefit from Sutent."
Because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.
Explore further: FDA panel backs Pfizer drug for kidney cancer
More information: The U.S. National Cancer Institute provides more information on kidney cancer.