Agent shows promise in slowing papillary kidney cancer

The first phase II study to investigate the use of the targeted therapy everolimus (Afinitor) for the initial treatment of advanced papillary kidney cancer has shown that it is successful in slowing or preventing the spread of the disease.

“Our results showed that for 59% of patients who received everolimus as their first-line treatment, their disease did not get worse and remained stable,” said co-author Bernard Escudier, MD, of the Institut Gustave Roussy in Villejuif, France. “These findings are important and indicate that more than half of these cancer patients are getting some kind of benefit from everolimus treatment.”

Study results were reported at the 2013 European Cancer Congress in Amsterdam, the Netherlands.

Dr. Escudier and colleagues from France, Germany, Italy, Spain, Poland, and the United Kingdom recruited 92 patients into the RAPTOR (RAD001 in Advanced Papillary Tumor Program in Europe) study, which started in July 2009. The patients, who had never received systemic treatment, were instructed to take the drug orally, once a day, at a dose of 10 mg for as long as they could tolerate it.

Of the 92 enrolled patients, 83 were included in an intent-to-treat (ITT) analysis and 63 were included in a per-protocol (PP) analysis. All of the 92 enrolled patients were included in the safety analysis. Tissue samples were analyzed by pathologists in the local hospitals to check whether or not the cancer had metastasized, and the samples were also checked centrally by an independent, expert group of pathologists.

According to the PP analysis carried out by the local investigators, disease was stable and had not progressed after 6 months in 59% of patients, while the central review confirmed this in 35% of patients. The local investigators found that the time that elapsed before the cancer spread or worsened (progression-free survival) was 7.8 months, while the central pathology review found it was 3.9 months. At least half of the patients were alive at 20 months.

Everolimus, also known as RAD001, is an oral inhibitor of mTOR (mammalian target of rapamycin). It is FDA approved to treat patients with advanced renal cell carcinoma whose disease has progressed on or after treatment with VEGF-targeted therapy.

“As far as we know, this study is unique as it was the first study of an mTOR inhibitor to only include patients with advanced papillary kidney cancer and diagnosis was also confirmed by an independent group of pathologists experienced in the classification of kidney cancer to prevent any tumors being classified incorrectly,” Dr. Escudier said.

“Everolimus represents another interesting treatment option for advanced papillary kidney cancer patients as it seems to extend their survival and time without the disease progressing.”

Adverse side effects were generally well tolerated and included weakness, tiredness, and anemia. Twenty-seven percent of patients discontinued everolimus due to these side effects.

The research was funded by Novartis Pharmaceuticals.

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