Short Course of Herceptin May Limit Heart Damage

Article date: February 24, 2006

Survival Benefit Seen With Just 9 Weeks of Treatment

Summary: Doctors from Finland confirm that early use of the drug Herceptin (trastuzumab) can keep breast cancer from returning in women whose tumors contain the protein HER2/neu. And they may have found a way to give the drug that prevents heart damage, a worrisome complication of treatment. Their results, first presented at a breast cancer conference in 2005, are now published in the New England Journal of Medicine.

Why it's important: Earlier studies of Herceptin found that some women who got the drug developed heart damage. In this study, the researchers were able to avoid that side effect by changing the way the drug is given. This paper is also another piece of evidence that confirms Herceptin's effectiveness when given to women with early-stage disease. Right now, the drug is only approved for use in women with breast cancer that has come back after treatment. Doctors in the US can prescribe it for women with early disease despite that fact, but the same is not true in many other countries. Many national health care systems overseas are reluctant to pay the high costs of Herceptin for early breast cancer treatment until they have convincing proof that it works in this situation.

What's already known: About 25%-30%f all breast cancers contain too much of a protein called HER2/neu. It is thought to be responsible in part for the cancer's growth, and tumors containing HER2/neu grow faster and are more likely to spread. Herceptin attacks this protein. Recently, several teams of doctors have shown that Herceptin given after surgery will slow the recurrence rate of HER2/neu-containing cancers and prolong women's lives. One problem has been that the drug also attacks similar substances in the heart and causes heart damage in some of the women.

How this study was done: This was a large study that tested different forms of chemotherapy to prevent recurrence in more than 1,000 women who had surgery for breast cancer. HER2/neu was found in the cancers of 232 of these women. Half (116) were given one of the chemotherapy regimens along with Herceptin and the other half received just the chemotherapy without Herceptin. The investigators were very careful with the way they gave the Herceptin. Previous studies have given the drug weekly for 1 year, often along with the chemotherapy, which in itself often contained drugs that can damage the heart. But in this study, the Herceptin was given for only 9 weeks, and before any heart-damaging chemotherapy.

What was found: Three years after surgery, women who received Herceptin were about 60% less likely to have suffered a recurrence of their cancer and about 60% less likely to die. The reduced death rate wasn't statistically significant, although it was close. Women on Herceptin did have a statistically significant drop in recurrences, though. Just as important was that these results were achieved without any heart damage. At the end of the study, women who received Herceptin had just as good heart function as women who didn't get the drug.

The bottom line: This is another study that shows the benefit of Herceptin for women with early-stage HER2/neu-containing breast cancer. The major new information from this research is that heart damage may be avoidable by not giving the Herceptin along with heart-damaging chemotherapy and giving the drug for only 9 weeks. This strategy also has the potential to save money, since less Herceptin would have to be used. However, the researchers caution that more studies need to be done to figure out the best way to give Herceptin so that women get the cancer benefits without the heart damage.

Citation: "Adjuvant Docetaxel or Vinorelbine with or without Trastuzumab for Breast Cancer." Published in the Feb. 23, 2006, New England Journal of Medicine (Vol. 354, No. 8: 809-820. First author: Heikki Joensuu, MD, Helsinki University Central Hospital, Finland.

Reviewed by: Members of the ACS Medical Content Staff

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