Drug May Help Curb Breast Cancer

Feb. 22, 2006 -- The breast cancer drug Herceptin may help prevent breast cancer's return in some patients, new research shows.

That finding comes from a study of about 1,000 women with early breast cancer. More than one in five of those women had the HER2/neu gene, which Herceptin targets.

The HER2/neu gene overproduces a protein called HER2. That protein is tied to faster-growing tumors that are more likely to return.

The new study shows fewer recurrences of breast cancer -- over three years -- in women with the HER2/neu gene who briefly took Herceptin with chemotherapy after breast cancer surgery.

The results appear in The New England Journal of Medicine. The researchers included Heikki Joensuu, MD, of Finland's Helsinki University Central Hospital.

Double Impact

In Joensuu's study, a total of 232 women had the HER2/neu gene.

The researchers randomly assigned half of those women to take Herceptin for nine weeks, along with chemotherapy drugs Taxotere or Navelbine. The other 116 women with the HER2/neu gene got chemo, but not Herceptin.

Over three years, 89% of those taking Herceptin plus chemotherapy survived without breast cancer's return. So did 78% of those who got chemo without Herceptin.

A short course of Herceptin plus chemo drugs Taxotere or Navelbine is "effective" in such patients, the researchers write.

Women in the study also got appropriate radiation therapy after chemotherapy. Radiation therapy was required for women who underwent breast-conserving surgery (lumpectomy). Patients with hormone-sensitive tumors were also scheduled to take tamoxifen for five years.

No Heart Risks Seen

Joensuu and colleagues found that Herceptin wasn't associated with heart failure or a drop in the heart's effectiveness at pumping blood in their study. However, heart failure is identified as an important side effect that can occur in 1% to 4% of patients who get it and 10% of patients with decreased heart function, according to an accompanying editorial.

However, the study was relatively small and the ideal length of Herceptin treatment isn't clear yet, the researchers note. They add that the chemo drugs used in the study weren't among a class of chemo drugs that may act with Herceptin to raise risk of heart problems.

The study "demonstrates that [Herceptin] can be given at therapeutically active doses with negligible cardiac side effects, but whether a similar result might hold in larger numbers of patients or in women with pre-existing heart disease is now a pressing question," states a journal editorial.

Kenneth Chien, MD, PhD, wrote the editorial. He is a professor at Harvard Medical School and the director of the Cardiovascular Research Center at Massachusetts General Hospital in Boston.