Iressa Shows Promise in Breast Cancer

A drug formerly approved as a second-line treatment for lung cancer, enhanced the effectivenss of hormonal therapy for the treatment of specific types of metastatic breast cancer, according to Cancer Wise. (Source: M.D. Anderson Cancer Center).

Iressa® was involved in a Phase II clinical trial and results were found to be surprising, representing the first positive study for the drug in the disease, according to a press release.

"The randomized study enrolled 93 women from 30 centers across the United States and Latin America, with M.D. Anderson enrolling 20 patients," stated press materials. "All of the women were newly diagnosed with metastatic breast cancer, with tumors that were hormone receptor positive and HER2-negative."

Patients in the study received daily doses of either Arimidex® and Iressa or Arimidex and a placebo. Arimidex is an aromatase inhibitor, a class of drugs that binds to and inhibits aromatse, the protein that helps produce estrogen, according to cancerwise.org.

Women who received Arimidex and Irressa experienced progression-free survival of 14.5 months, compared to 8.2 months in the women who received Arimidex with Iressa, the site stated. Of the women taking the combination, 47 percent had stable disease for more than 24 weeks and 49 percent showed a clinical benefit. Of the women taking Arimidex alone 22 percent had stable disease for over 24 weeks and 34 percent showed a clinical benefit, according to statistics.

Iressa, a once-a-day tablet, was the first in a new class of anti-cancer drugs known as epidermal growth factor receptor tyrosine kinase inhibitors to become commercially available, according to the M.D. Anderson Cancer Center.

"However, in 2005, after a large international study resulted in negative findings and numerous negative side effects, the drug's labeling was altered by the FDA," the release stated. "During this period, Iressa was being tested in clinical trials in a number of cancer types, including breast cancer."