"When you go after a specific target in a patient's tumor, the treatment is likely to be more effective and less toxic," said Schiff.
The tumors in question – nearly 25 percent of all breast cancers – have high levels of HER-2. While the HER-2 makes the tumors more aggressive, it also provides a target against which new drugs can act.
Previously, treatment for patients with HER-2 positive tumors was less effective.
"Now we have effective treatment, and survival is markedly improved," said Dr. Grazia Arpino, lead investigator of the study and a postdoctoral fellow at BCM.
"These tumors are initially highly sensitive to a drug known as trastuzumab or Herceptin, one of the drugs used in combination in the mouse study and which is approved by the FDA (U.S. Food and Drug Administration) for treatment," said Schiff.
However, the tumor is wily and can sometimes escape the drug's effects, resulting in resistance. Adding two other experimental drugs – gefitinib and pertuzumab -- that inhibit HER-2 in different ways can more completely block the growth signals in the tumor, causing it to die.
In one of the tumors studied in this report, blocking the stimulatory effects of estrogen on the tumor was also necessary for optimal treatment, said Schiff. Completely blocking the HER pathway is critical, she said. Leaving out just one of the three drugs was much less effective.
A clinical study using drug combinations in newly diagnosed patients with HER-2 positive breast cancer will start soon under the direction of physicians at BCM's Breast Center, said Osborne.
"We are very excited to see if our laboratory results can be translated to patients with the more aggressive types of breast cancer," he said.
Others who participated in the research include Carolina Gutierrez, Heidi Weiss and Mothaffar Rimawi of BCM, Suleiman Massarweh, now of the University of Kentucky, Lavina Bharwani now of Johns Hopkins Singapore International Medical Center in China, and Sabino De Placido of Universita di Napoli Federico of Naples, Italy.
Funding for this research comes from the National Institutes of Health, The Jacqueline Seroussi Memorial Foundation for Cancer Research and the Susan G. Komen for the Cure (previously Susan G. Komen Breast Cancer) Foundation. |
