TUESDAY, April 26, 2005 (HealthDay News) -- The news that two trials of the breast cancer drug Herceptin were halted early due to promising results was hailed by experts as a major advance in the treatment of a particularly aggressive form of the disease.
Genentech Inc., the manufacturer, and the National Cancer Institute (NCI), which sponsored the trials, announced late Monday that the drug had successfully prolonged life and dramatically decreased recurrence rates for women with early-stage HER-2 positive breast cancer.
"This turns someone who had a poor prognosis into someone who has a good prognosis," said Dr. Jo Anne Zujewski, the head of breast cancer therapeutics in the clinical investigations branch of the Cancer Treatment Evaluation Program at the NCI. "It basically eliminates the negative prognostic factor for this type of cancer."
"This is very important news," added Dr. Jay Brooks, chairman of hematology/oncology at the Ochsner Clinic Foundation in Baton Rouge, La. The Ochsner Clinic had several patients enrolled in the trials.
Patients with early stage HER-2 positive breast cancer who were given Herceptin in combination with chemotherapy had a 52 percent decrease in their risk for a recurrence compared with patients who received chemotherapy without the drug. All the patients had also undergone surgery to remove the malignancy.
"It's very striking. We don't often see 52 percent," Zujewski said. "Undoubtedly, there will be a group of women for which this will be a good idea."
HER-2 positive breast cancers produce too much of the HER-2 protein, which stands for human epidermal growth factor receptor 2 and is found on the surface of the cells. These tumors tend to grow faster and are more likely to recur than tumors that are HER-2 negative. "It's one of the most aggressive tumors," Zujewski said.
About 40,000 to 50,000 of the 200,000 women who develop breast cancer annually in the United States have HER-2 positive tumors.
"This is a major advance for those women," Brooks said.
Herceptin, also known as trastuzumab, is a targeted therapeutic antibody, meaning it has a specific mechanism of action, and is already approved for metastatic breast cancer. The drug, however, can have serious side effects, including cardiac failure.
Previously, women with this type of breast cancer typically underwent surgery, radiation and chemotherapy.
The women in these trials had early stage, invasive breast cancer, meaning the cancer cells had moved beyond the breast duct and had the potential to travel to other areas of the body, Zujewski explained. In many cases, the cancer had already reached the lymph nodes.
In order to make their decision, the Data Monitoring Committees overseeing the trials analyzed data on 3,300 patients. This analysis revealed the 52 percent decrease in disease recurrence in patients who received Herceptin plus chemotherapy, a "highly statistically significant" number.
The specific results will be presented at the annual meeting of the American Society of Clinical Oncology on May 16.
Herceptin was approved in 1998 to treat metastatic breast cancer. Colleen Wilson, associate director of product communications at Genentech, said that the company "plans to obtain data from the cooperative groups and share it with the FDA to discuss a potential filing for Herceptin in HER2-positive, adjuvant breast cancer."
"My sense is that because it's been approved for metastatic breast cancer, some people will use it off label before the FDA reviews it," Zujewski said. "If the FDA approves it [for the new application], it will get even more widespread use."
For now, Zujewski added, physicians will "have to do sort of an individual patient risk-benefit analysis."
For the future, the drug may hold the promise of more than just a treatment. "We would rather prevent a recurrence than treat it when it comes," Zujewski said. 'When we prevent recurrences, we have the real potential for a cure. That's why this is so exciting."
The findings also offer hope beyond breast cancer. "This proves the principle that we can enhance our chemotherapy regimens for specific populations with targeted agents,"' Zujewski said. "It goes beyond breast cancer. It's a major advance in a major disease."
The National Cancer Institute has more on Herceptin.