© 2005-2012 American Society of Clinical Oncology (ASCO). All rights reserved worldwide.
Two new drugs, sunitinib (Sutent) and temsirolimus (CCI-779), benefit patients with advanced renal cell carcinoma, a common type of kidney cancer, according to two different clinical trials. Advanced kidney cancer is hard to treat and there is no effective chemotherapy for it. The standard treatment is interferon-a (Roferon) or interleukin-2 or aldesleukin (Proleukin), but these drugs only work in a small number of patients and are associated with serious side effects.
Sunitinib is a pill given by mouth, and temsirolimus is a drug that is given intravenously (through a vein). Both drugs block angiogenesis (the process of new blood vessel formation) in different ways. Angiogenesis is necessary for kidney cancer to grow and spread.
In the first study, 375 patients with advanced kidney cancer received sunitinib, and 375 patients received interferon-a. Most patients had surgery to remove the tumor or diseased kidney, and none received prior chemotherapy. Researchers found that the cancer did not worsen after 47 weeks in the patients receiving sunitinib, compared with 25 weeks in the patients receiving interferon-a. In addition, the tumors shrank in nearly a quarter of the patients receiving sunitinib, compared with 5% of the patients receiving interferon-a.
"As a result of this trial, we believe that sunitinib will become a new standard of care for advanced renal cell cancer," said Robert J. Motzer, MD, Attending Physician at Memorial Sloan-Kettering Cancer Center in New York City and the study's lead author. Dr. Motzer added that the side effects included fatigue and reduced blood counts. The second study evaluated temsirolimus as the initial treatment for high-risk patients with advanced kidney cancer. All patients had a poor prognosis (chance of recovery), based on a standard set of criteria, such as the spread of cancer to multiple places in the body. Typically, these high-risk patients live less than six months.
Of the 626 patients enrolled in the study, 207 received interferon-a, 209 received temsirolimus, and 210 received both therapies. The patients receiving temsirolimus survived the longest (11 months), compared with the patients receiving interferon-a (7 months) or the combination of these drugs (8 months).
The most common side effect was asthenia (weakness and fatigue), which was not as common for patients receiving temsirolimus. Because of how temsirolimus works, it had other side effects, such as rashes and increased blood glucose levels, which were mild and easily controlled.
"Until just a few years ago there were no promising drugs for kidney cancer. Now there are two that have recently been approved by the U.S. Food and Drug Administration (FDA), and several more that are looking very good in clinical trials," said Gary R. Hudes, MD, Director of the Genitourinary Malignancy Program at Fox Chase Cancer Center in Philadelphia and the study's lead author. "Temsirolimus is the first of these new drugs to show an overall survival advantage for kidney cancer. In addition, this was the first study for patients whose cancer was so advanced they would not qualify for most other clinical trials."
What This Means For Patients
Both of these studies provide treatment options for advanced kidney cancer. The sunitinib study shows that it slowed cancer growth and shrank tumors. The temsirolimus study finds that it helps high-risk patients live longer and has few side effects.
It is not yet known whether sunitinib extends the lives of patients with this cancer. The FDA approved sunitinib in January 2006 for advanced kidney cancer. The researchers plan to compare the differences in fatigue (extreme tiredness) and quality of life between the two groups of patients. Temsirolimus is not approved by the FDA, which means that it is only available as part of a clinical trial.