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Herceptin Helps Reduce Deaths from Advanced Breast Cancer (dateline March 21, 2001)

When combined with standard chemotherapy, the drug Herceptin (generic name, trastuzumab) significantly increases the chances of survival for some women with advanced breast cancer, according to a newly published study. Approximately 25% to 30% of advanced (metastatic) breast cancer patients carry extra copies of the HER2 gene (also written HER2/neu), which usually signals aggressive cancers. Herceptin targets this cancer and results in fewer deaths from breast cancer. However, Herceptin does increase the risk of serious heart problems, and patients need to be monitored by physicians for potential complications.

In the study, Dennis J. Slamon, MD, PhD and his colleagues randomly assigned 469 advanced breast cancer patients to receive standard chemotherapy alone or chemotherapy with Herceptin. All of the patients had tested positive for HER2 gene overexpression and thus were candidates for Herceptin. Depending on the patients’ previous treatment, the chemotherapy regimens given in the trial were:

  1. AC regimen: an anthracycline—either Adriamycin (generic name, doxorubicin) or Ellence (generic name, epirubicin)—and Cytoxan (generic name, cyclophospamide) with or without Herceptin
  2. Taxol (generic name, paclitaxel) with or without Herceptin

After one year, Dr. Slamon and his colleagues observed fewer deaths among the women who took Herceptin: only 22% of the women who took Herceptin died after one year compared with 33% of the women who did not take Herceptin.

"The study by Slamon et al. is a landmark trial…. This is the beginning of an important new era in cancer treatment since many more targeted therapies are now undergoing clinical evaluation," wrote Elizabeth A. Eisenhauer, MD, in an accompanying editorial in The New England Journal of Medicine. The average survival time was also greater among the women who took Herceptin: 25 months compared to 20 months among the women who did not take Herceptin.

While the results of the study show that Herceptin can be beneficial for women with advanced breast cancer, the researchers did find that serious heart problems (cardiotoxicity) can also occur. Cardiac dysfunction occurred in 27% of the women on Herceptin who also took the AC chemotherapy regimen, and in 8% of the women who took Herceptin with Taxol. "Although the cardiotoxicity was potentially severe and, in some cases, life-threatening, the symptoms generally improved with standard medical management," wrote Dr. Slamon and his colleagues. Thus, patients who take Herceptin should be monitored by physicians for heart problems.

The most common side effects of Herceptin include:

  • Fever and chills
  • Weakness
  • Nausea or vomiting

In rare cases, women may have serious adverse reactions to Herceptin, including allergic shock and respiratory distress. These reactions were not observed in clinical trials prior to drug approval by the U.S. Food and Drug Administration (FDA) in 1998, but warning labels have been amended since then to include these possible effects. Herceptin is currently FDA approved to treat advanced (metastatic) breast cancer patients who carry extra copies of the HER2 gene. While Herceptin has been approved to be used in conjunction with Taxol, it is not approved for use with the AC chemotherapy regimen outside of clinical trials. Researchers are currently planning four large clinical trials to determine whether Herceptin is helpful for early-stage breast cancers. The trials will enroll more than 10,000 patients at 800 sites worldwide.

Metastatic breast cancer is the most advanced form of breast cancer, in which cancer cells have spread out of the breast to invade other areas of the body, such as the bone, liver or lung. The approach to treating advanced breast cancer focuses largely on relieving cancer symptoms and extending survival time. Promising new research, including this most recent study with Herceptin, is giving advanced breast cancer patients more treatment options.

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