CHICAGO—Patients with metastatic renal cell carcinoma (mRCC) prefer pazopanib over sunitinib because the former is associated with a better quality of life (QOL) and less fatigue, according to study findings presented at the American Society for Clinical Oncology 2012 annual meeting.

In a double-blind, randomized crossover study, 168 mRCC patients were randomized to pazopanib for 10 weeks followed by a two-week break and then sunitinib for 10 weeks, or vice versa.  In the primary analysis of 114 patients, 70% preferred pazopanib, 22% preferred sunitinib, and 8% had no preference. The differences were statistically significant. The most common reasons that patients gave for preferring pazopanib were better QOL and less fatigue. In addition, patients on pazopanib had fewer dose reductions than those taking sunitinib (13% vs. 20%) as well as fewer treatment interruptions (6% vs. 12%).

“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,” said lead investigator Bernard J. Escudier, MD, of the Institut Gustave Roussy, Villejuif, France. Study findings provide “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.”

How patients feel when they take a drug over many months is not reflected in traditional adverse event reporting, he said. Patient-reported outcomes like these, however, are being added to traditional efficacy outcomes to better understand the clinical relevance of differences in toxicity between therapies. In this current environment, mRCC patients may take therapies for several years. QOL differences between two therapies may appear relatively modest to physicians, but can be perceived very differently by patients who may have to take therapies for many months or years.

Physician preference was not as strong as patient preference: 60% preferred pazopanib, 21% preferred sunitinib, and 21% had no preference.  The study was funded by GlaxoSmithKline, the maker of pazopanib, and involved several European, U.K., and U.S. cancer centers.

“Drugs with relatively similar safety profile can be perceived very differently by patients, and the difference observed in this study is more than any expectation we had before embarking into this study,” Dr. Escudier told Renal & Urology News. “This difference will be important to explain to patients with kidney cancer when they could receive both drugs. Patient preference should become a major endpoint to consider in oncology, especially with development of chronic therapy and by consequence of chronic toxicities. The grading system used in oncology today is more accurate to describe acute toxicity that low-grade chronic toxicity. As an example, having fatigue or nausea three days a month is very different than having continuous fatigue or nausea, even if grade of toxicity is lower.”

Urologist Robert G. Uzzo, MD, FACS, Chairman of the Department of Surgery at Fox Chase Cancer Center in Philadelphia, said the study findings are novel. As mRCC becomes more of a chronic condition instead of a terminal illness, patient preferences will become a bigger concern for physicians, Dr. Uzzo said.

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