Targeted Kidney Cancer Drugs Show Promise

Therapies extend survival for the most advanced cases

SUNDAY, June 4, 2006 (HealthDay News) -- The treatment of kidney cancer, a notoriously difficult disease to overcome, is moving into a new era, oncologists reported Sunday.

Results of two phase III trials of targeted therapies, presented at the annual meeting of the American Society of Clinical Oncology (ASCO) in Atlanta, showed significant improvements for patients with advanced forms of the malignancy.

"These drugs and more which are in development really do hold promise for longer survival for people with kidney cancer," said Dr. Gary R. Hudes, director of the genitourinary malignancy program at Fox Chase Cancer Center in Philadelphia. "It's been a refractory disease. Even two to three years ago, there weren't many options for these patients."

Hudes was lead author of one trial that found an investigational drug named temsirolimus used as first-line treatment improved survival for advanced kidney cancer patients.

"We are absolutely entering a new era," added Dr. Robert J. Motzer, attending physician at Memorial Sloan-Kettering Cancer Center in New York City and lead author of the second trial. "These drugs are resulting in a complete shift towards targeted therapies."

Temsirolimus targets mTOR, a protein that regulates cell growth and angiogenesis, the growth of blood vessels that supply tumors.

More than 600 patients were randomized to receive temsirolimus, or the standard treatment, interferon, or a combination of the two. All participants had kidney cancer that had spread to other parts of the body and had such a poor prognosis they would not qualify for most other clinical trials.

"That's what makes this study different," Hudes said. "This was a much sicker group of patients. They had the most adverse features of the disease."

Overall survival in the temsirolimus group was 10.9 months, compared to 7.3 months in the interferon group and 8.4 months in the combination group. Progression-free survival was 3.7 months in the temsirolimus group and in the combination group and 1.9 months in the interferon group.

Typically, such patients, who comprise 20 percent of all those with metastatic kidney cancer, live only six months or less.

"We were able to improve survival by almost 50 percent," Hudes said. "We think this is worthy of attention and worthy of further development in other people with kidney cancer."

The study was funded by Wyeth Pharmaceuticals, which makes the drug.

A second study found that Sutent (sunitinib), a pill already approved for both advanced kidney cancer and a rare type of stomach cancer, increased survival for people with metastatic renal cell carcinoma, the most common type of kidney cancer.

The international Phase III trial involved 750 patients with advanced clear cell carcinoma (representing about 90 percent of all renal cell cancers) who had not undergone chemotherapy, although some had had surgery.

Patients on Sutent had progression-free survival of 47.3 weeks versus 24.9 weeks for those on interferon in what was the first head-to-head comparison of the two drugs.

"There was a substantial improvement in progression-free survival and quality of life," Motzer said. "It should be offered as a first-line treatment. It's an option, and it's available to patients."

On Saturday, other researchers at the meeting reported that Sutent shrank tumors or prevented disease progression in about half the test patients with advanced non-small cell lung cancer who were not responding to standard therapy.

FDA approval of the drug was based on separate Phase II trials of people for whom chemotherapy had failed. The drug is made by Pfizer, which funded the current study.

Yet a third Phase III trial showed that the addition of the chemotherapy agent Taxotere (docetaxel) to the standard initial chemotherapy for head and neck cancer reduced the risk of death by 30 percent. Overall survival at three years was 62.1 percent for those in the Taxotere group versus 48.1 percent for those in the control group.

More information

Visit the National Cancer Institute for more on kidney cancer.

SOURCES: Gary R. Hudes, M.D., director, genitourinary malignancy program, Fox Chase Cancer Center, Philadelphia; Robert J. Motzer, M.D., attending physician, Memorial Sloan-Kettering Cancer Center, New York City; June 4, 2006, presentations, American Society of Clinical Oncology, Atlanta
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