Zosia Chustecka

June 02, 2012

June 2, 2012 (Chicago, Illinois) — In an innovative trial that focused on how patients felt on treatment, the majority of patients with metastatic kidney cancer preferred pazopanib (Votrient, GlaxoSmithKline) over sunitinib (Sutent, Pfizer).

"This was surprising," said lead author Bernard Escudier, MD, from the Institut Gustave Roussy in Villejuif, France. "We never expected such a big difference in patient preference."

The trial involved 168 patients who took one of the drugs for 10 weeks and then the other for 10 weeks. They were then asked which drug they preferred.

Of the 126 who completed the questionnaire, 70% said they preferred pazopanib, 22% said they preferred sunitinib, and 8% expressed no preference. The main reasons cited were better overall quality of life and less fatigue, but patients also reported less change in food taste, less soreness in the mouth/throat, and less foot and mouth syndrome with pazopanib.

The treating physicians showed a similar preference, with 61% preferring pazopanib, 22% preferring sunitinib, and 17% expressing no preference.

Dr. Escudier also noted that were fewer dose reductions with pazopanib than with sunitinib (13% vs 20%), and that fewer patients discontinued because of adverse events. In the first 10-week period of the trial, 18% discontinued sunitinib and 14% discontinued pazopanib; in the second 10-week period, 31% discontinued sunitinib and 15% discontinued pazopanib.

Patient Preference Is a New Factor

Patient preference is a new factor to take into consideration when choosing which drug to prescribe, said Dr. Escudier. There are now 7 drugs approved for first-line use in metastatic kidney cancer, so "we have a luxury of choice," he said. "But no drug is outstanding, so which drug should we choose?"

The results were highlighted at a press conference held here at the 2012 Annual Meeting of the American Society of Clinical Oncology. One journalist asked whether these results can be believed, considering that the study was sponsored by GlaxoSmithKline, the manufacturer of pazopanib. Press conference moderator Carol Aghajanian, MD, chief of the gynecologic medical oncology service at the Memorial Sloan-Kettering Center in New York City, emphasized that this was a randomized controlled double-blind clinical trial in which neither the patients nor their physicians knew who was taking which drug.

However, when discussing the trial after its presentation, Tim Eisen, MD, from the University of Cambridge, United Kingdom, noted the "strong concordance" between patient preference and physician preference. "I question how blinded the physicians were in this setting," he said.

Dr. Aghajanian said that she thinks these results will influence clinical practice. "People will listen," she said; patients will hear about these results and might ask for a specific drug.

Comments From Competitor

However, the trial was criticized by Pfizer, the manufacturer of sunitinib, for being short term (assessment was at 22 weeks) and for not taking into account long-term efficacy.

Robin Wiltshire, MB CHB, global medical affairs head for sunitinib at Pfizer, said that sunitinib has the best efficacy data in metastatic kidney cancer, and that its overall survival beyond 2 years has not been seen with any of the other new drugs. "These efficacy results have yet to be paralleled," he told Medscape Medical News.

Sunitinib is a clear market leader in the field of metastatic kidney cancer, Dr. Wiltshire said. It holds about 50% to 70% of the market share for first-line use, and more than 100,000 patients have been treated so far.

Perhaps this explains some of the rationale behind the trial that focuses on patient preference — it gives the manufacturer of pazopanib a claim to fame in a crowded marketplace, into which it made a late entry.

When pazopanib was approved for use in metastatic kidney cancer by the US Food and Drug Administration in 2009, it was the sixth drug to be approved for this indication.

Dr. Escudier said that this study of patient preferences used response rate as a measure of efficacy at 22 weeks, which was similar for the 2 drugs. "In our hands, the 2 drugs have been similarly effective in this patient population," he said. There have not been any studies directly comparing the 2 agents, although such a study, known as COMPARZ, is currently in progress; it is also sponsored by GlaxoSmithKline, he noted.

After the presentation at the meeting, one delegate pointed out that in this small trial of patient preferences, there was a difference in progression-free survival at 22 weeks between the 2 drugs. Dr. Escudier acknowledged that there was a small numerical difference in progression-free survival favoring sunitinib, but he repeated that the real comparison of efficacy is the ongoing COMPARZ trial. He said he will wait until those results come out before making firm recommendations. In the meantime, if patients ask him which drug to choose, he will refer to the patient preference data and recommend pazopanib, he said.

Dr. Eisen said the trial had "a novel design with an internal control for an abstract concept that is hard to measure." However, he cautioned that these results on patient preference should only serve as an "adjunct" to comparative data on efficacy.

The trial was sponsored by GlaxoSmithKline. Dr. Escudier reports serving in a consultant or advisory role for GlaxoSmithKline, AVEO Pharmaceuticals, Novartis, Bayer, and Pfizer.

2012 Annual Meeting of the American Society of Clinical Oncology (ASCO): Abstract CRA4502. Presented June 2, 2012.

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