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Sutent Shows Promise in Metastatic Breast Cancer
By Marilynn Larkin
Sutent (sunitinib), an oral drug already approved to treat advanced kidney cancer and a rare digestive system tumor, now shows some efficacy in advanced breast cancer, according to a study published in the Journal of Clinical Oncology (April). Sutent is an angiogenesis inhibitor, thought to work by preventing a tumor from getting the oxygen and nutrients it needs to grow by blocking the formation of new blood vessels.
“The whole area of angiogenesis is really taking off in breast cancer,” says Harold Burstein, MD, PhD, of the Dana-Farber Cancer Institute, lead author of the study. “Several anti-angiogenesis drugs are being studied, sunitinib among them.” Sutent is in a class of drugs called receptor tyrosine kinase (RTK) inhibitors. It prevents certain growth factors necessary for angiogenesis from signaling that a tumor needs more blood vessels to survive and grow. Thus, it effectively cuts off the blood supply to the cancer and stops tumor cells from reproducing.
In the study 64 women with metastatic breast cancer who had been pretreated with other drugs were given 50 mg of Sutent once daily for four weeks, then were off treatment for two weeks. Seven patients had a partial response, resulting in an overall response rate of 11 percent. “Truthfully, this is a reasonable response rate for most single-agent chemotherapies in this population,” Burstein says. The drug was “reasonably well tolerated,” he adds, noting that fatigue was the most common side effect reported with Sutent.
Sutent is now being tested in four phase 3 and three phase 2 trials in various settings, to evaluate its safety and efficacy both as a single agent and in combination with first-line therapies to treat locally advanced and metastatic breast disease.
“What we’re really seeing is the second generation of anti-angiogenesis work in breast cancer,” Burstein explains. “With the first generation of trials, it seemed like these drugs would be valuable. Now we want to see how they compare with each other, how to integrate them and how to choose the best.” More information on the trials, which are currently recruiting patients, can be found at clinicaltrials.gov or suntrials.com.
