Targeted Drugs Slow Kidney Cancer
Drugs That Target a Tumor's Blood Supply May Help Treat Advanced Kidney Cancer
The Sunitinib Findings
The newly reported sunitinib trial included 750 previously untreated patients with advanced kidney cancer. About half of the patients were treated with a standard course of the oral drug and about half received a standard course of interferon alfa.
Researchers reported that the median time it took tumors to grow, known as disease-free progression, was more than twice as long in the sunitinib-treated patients than in those treated with interferon -- 11 months vs. five months.
And 31% of the patients on the newer drug had improvements from treatment -- as seen on radiologic imaging -- compared with just 6% of the interferon-treated patients. As a group, the sunitinib patients also reported significantly better overall quality of life than the patients treated with interferon.
Researcher Robert J. Motzer, MD, of New York's Memorial Sloan-Kettering Cancer Center, tells WebMD that it is still not clear if treatment with sunitinib keeps patients alive longer, but he adds that there is good reason to believe that it does.
"You would expect that more than a doubling in disease-free survival would translate into longer overall survival, but we can't say that yet," he says.
The Sorafenib Study
Unlike the patients in Motzer's trial, those in the sorafenib study had already been treated, mostly with either interferon alfa or interleukin-2. All were considered treatment resistant.
Half of the 903 study participants received sorafenib and the other half received placebo.
Compared with placebo-treated patients, patients treated with sorafenib also had longer median progression-free survival (5.5 months vs. 2.8 months), and a higher response rate (10% vs. 2%).
There was a greater incidence of toxic side effects in the sorafenib-treated patients. The most commonly reported toxicities were diarrhea, rash, fatigue, and unpleasant skin reactions in the hands and feet. Serious adverse events included heart problems in 12 patients and hypertension.
In the study by Motzer and colleagues, just under a third of patients reduced their dosage of the antiangiogenesis drug due to these toxicities.
Motzer says the next step for researchers is to determine if responses improve when sunitinib, sorafenib, and similar therapies are given in combination.
"For many years, kidney cancer has been considered to be among the most treatment-resistant cancers," he says. "In the past there has been little hope for success with any treatment, but these drugs are changing that."