FRIDAY, Dec. 10, 2010 (HealthDay News) -- Combinations of targeted therapies for an especially aggressive type of breast cancer could potentially usher the majority of affected patients into remission, researchers at a major breast cancer meeting said Friday.
Presenting results from three trials at the annual San Antonio Breast Cancer Symposium, scientists explained that administering two or more drugs designed to treat HER2-positive tumors resulted in much higher remission rates than doses of any one drug or standard chemotherapy alone.
Given to patients several weeks before cancer surgery, with or without chemotherapy, the medications often shrank tumors dramatically or eradicated them altogether, the researchers said.
HER2-positive cancer is receptive to a protein called human epidermal growth factor receptor 2, which promotes the growth of malignant cells. Drugs that specifically target HER2 cells -- including Herceptin, Tykerb and pertuzumab -- have been proven effective on these types of tumors, which tend to be more aggressive than other breast cancers.
"I think it's a very exciting era, because we've gone from a very lethal era . . . to a point where we might be able to cure this disease," said Dr. Neil Spector, a professor of medicine at Duke University Medical Center, who moderated the symposium session.
Using Tykerb and Herceptin combined with chemotherapy before surgery, researchers followed 2,500 women with early breast cancer at 85 facilities throughout Germany. About half of these patients achieved remission before surgery, said Dr. Michael Untch, head of the multidisciplinary breast cancer department at Helios Clinic in Berlin.
"In a majority of these patients, we could do breast-conserving surgery where previously they were candidates for mastectomy," Untch said.
The team will continue following the patients to see if remission at surgery affects their outcome.
Another study showed the combination of pertuzumab and Herceptin, when given with the chemotherapy drug docetaxel, eradicated 46 percent of tumors, 50 percent more than the results achieved without pertuzumab. Also, 17 percent of tumors were eradicated by combining the two targeted drugs and skipping chemotherapy, the researchers said.
"Our study is the only one that has tested the hypothesis that [pertuzumab and Herceptin] could work without chemotherapy in these women," said lead researcher Dr. Luca Gianni, director of medical oncology at the Fondazione IRCCS Istituto Nationale Tumori Fondazione IRCCS Istituto di Milano in Italy.
The third study, which included 455 patients followed at 99 sites for nearly two years, indicated that a combination of Tykerb, Herceptin and the chemotherapy drug Taxol improved tumor response rates significantly more than any of the drugs alone.
The mix led to a 51 percent remission rate, compared to 29 percent for a single therapy, said lead researcher Dr. Jose Baselga, chief of the division of hematology and oncology and associate director of the Massachusetts General Hospital Cancer Center.
"With these new therapies, we could easily go to curing over 90 percent of these patients, which is remarkable since this was the most lethal kind of breast cancer 10 years ago," said Baselga.
"This is a very fast advancement of new therapies," Untch agreed.
Researchers countered negative side effects of the drugs, which included diarrhea, liver function abnormalities, skin disorders and a low white blood cell count, by lowering patients' dosages or administering additional medications to alleviate specific symptoms.
Describing targeted therapies as a "HER2 blockade," Spector said if cost was not an issue, he would use all three drugs on HER2-positive breast cancer patients.
Discussing the high cost of treatment at the session, the researchers noted that spending more money on faster-acting, more effective treatments could save other treatment expenditures down the line.
"I do think we need to be creative in the ways we [run through] this data to make things more affordable," Spector said.
Because this study was presented at a medical meeting, the findings should be viewed as preliminary until they are published in a peer-reviewed journal.
To learn more about surgical options for breast cancer, visit the American Cancer Society.