According to a new multicenter study, the drug sunitinib malate (Sutent) is more effective than the current standard cytokine treatment given as initial therapy for patients with metastatic renal cell carcinoma. The study was presented at the annual American Society of Clinical Oncology meeting in Atlanta.

"This drug has shown more activity as a single agent against advanced kidney cancer than any other drug I've studied in the past 15 years," said the study's lead author, Robert J. Motzer, MD, a medical oncologist at Memorial Sloan-Kettering Cancer Center. "I continue to be encouraged by its effectiveness in treating patients with this aggressive disease," said Dr. Motzer, who is a leader in the treatment of kidney cancer and conducted the earliest clinical trials on sunitinib (initially referred to as SU11248).

First-Line Efficacy

Interferon-alpha is one of the standard treatments for advanced kidney cancer, but only about 15% of patients respond to this immunotherapy. Sunitinib targets receptors on kidney cancer cells that may play a role in tumor growth and the development of blood vessels that feed a tumor. Previous clinical trials, also led by Dr. Motzer, showed that sunitinib caused some renal cell cancers to shrink, but this study is the first to demonstrate its effectiveness as a first-line therapy compared with standard cytokine therapy.

The randomized trial included 750 patients over age 60, half of whom were treated with a 6-week cycle of sunitinib and half of whom were treated with a 6-week cycle of the current treatment standard, interferon-alpha. The primary end point of the trial was a comparison of progression-free survival between sunitinib and interferon-alpha as assessed by independent third-party review. The median progression-free survival for treatment with sunitinib was 11 months, compared with 5 months following treatment with interferon-alpha. This outcome was statistically significant and met the trial's primary end point. In addition, 31% of the patients in the sunitinib arm of the study experienced substantial tumor shrinkage compared with 6% of the patients receiving standard treatment.

Advanced Lung Cancer

Results of another multicenter study presented at the Atlanta ASCO meeting indicate that sunitinib may also be effective for patients with recurrent and advanced lung cancer. Principal Investigator Dr. Mark A. Socinski, associate professor of medicine at the University of North Carolina at Chapel Hill and a clinical faculty member of the UNC Lineberger Comprehensive Cancer Center said the activity data on sunitinib appear "very similar" to that of other currently approved agents for non-small-cell lung cancer (NSCLC).

"As a single-agent, this drug worked in a difficult group of patients whose advanced disease had been previously treated with other chemotherapies and whose options were limited," Dr. Socinski said. According to the UNC thoracic oncologist, among 63 patients treated in this phase II trial, there were 6 confirmed partial responses, with disease stabilized in an additional 27. He said data as to length of survival "are still pending."

Sunitinib treatment involved an oral dose of 50 mg/d for 4 weeks followed by 2 weeks off treatment. Adverse effects of the drug included fatigue, nausea, vomiting, abdominal pain, and high blood pressure. Two patients developed a pulmonary hemorrhage and one a cerebral hemorrhage.