ATLANTA -- For decades, it has been one of cancer's great mysteries: Why do about 4 percent of kidney tumors spontaneously disappear?
Doctors believed that if the immune system were defeating the cancer, treatments to boost it might help the others, but that hasn't worked very well. Now, three new drugs are displacing the immune system theory and attacking the disease in different ways.
An experimental drug,
Today, fresh results are expected on a third drug, Nexavar, which is made by
``Until just a few years ago, there were no promising drugs for kidney cancer," said Dr. Gary Hudes of Fox Chase Cancer Center in Philadelphia, who led the study on the Wyeth drug.
There still is no cure, ``but these drugs can control the disease for a significant amount of time" and may offer more benefit when given earlier in the course of the disease, he said.
The drugs were discussed yesterday at a meeting in Atlanta of the American Society of Clinical Oncology.
About 39,000 new cases of kidney cancer and 12,800 deaths from it are expected in the United States this year. Smoking is the top risk factor. About one-third of cases spread throughout the body, a situation currently incurable.
Temsirolimus is part of a new generation of cancer drugs that, unlike chemotherapy, attack cancer in more precise ways.
This drug is the first to target mTOR, a signaling chemical that controls cell growth and the formation of blood vessels that nourish tumors.
Patients who received the drug lived about 11 months versus about seven months for those given interferon, an immune system treatment.
Fatigue and severe side effects were more common in those receiving interferon. Mild anemia, rash, and mouth sores were more common with the novel drug ``but easily manageable," Hudes said.
In the other study, Sutent, which targets different cell signals, delayed the growth of cancer for 11 months compared with five months for those given interferon, said Dr. Robert Motzer of Memorial Sloan-Kettering Cancer Center in New York.
High blood pressure, diarrhea, and fatigue occurred in 5 to 8 percent on the new drug.
In other news at the conference yesterday, researchers said Sutent also showed promise in a small mid-stage trial as a treatment for the most common form of lung cancer.
Its effectiveness was comparable to that seen in earlier mid-stage trials of
``Both of these agents seem able to stablize tumors and prevent them from growing," said Johnson, who did not conduct the Sutent trial but helped explain its findings.
Material from Reuters was included in this report.