Tykerb May Help Late-Stage Breast Cancer

(WebMD)  A combination of breast cancer drugs — Tykerb and Xeloda — slows metastatic breast cancer after Herceptin finally fails. However, the combination treatment did not extend patients' lives in an international clinical trial.

In the trial, Charles E. Geyer, M.D., of Allegheny General Hospital, Pittsburgh, and colleagues studied 324 women with metastatic breast cancer, meaning their cancer had spread to other organs. Nearly all had been treated with Herceptin for a median of 42-44 weeks.

Half the women then got Xeloda chemotherapy; the other half got the Tykerb/Xeloda combination.

Those who got the combination therapy had more than a 50% delay in disease progression. Their cancer once again began to spread after a median 8.4 months, vs. 4.4 months for those who got Xeloda alone.

Adding Tykerb to the Xeloda did not worsen the side effects of the cancer chemotherapy. However, it also did not increase the amount of time the women lived.

Tykerb is one of the new targeted treatments for cancer — a promising weapon in the arsenal against the disease.

About 20% of breast cancer patients have HER2-positive cancers — tumors that have too much of a type of protein called HER2 protein. Herceptin, a man-made antibody, targets these cancers.

But metastatic breast cancer eventually becomes resistant to Herceptin. Moreover, metastatic HER2-positive breast cancer often spreads to the brain, where Herceptin and other chemotherapies can't reach.

Researchers have searched for new drugs that target HER2 and that can enter the central nervous system. Tykerb is such a drug.

The findings from this trial of Tykerb with Xeloda appear in the Dec. 28 issue of The New England Journal of Medicine.

In an editorial accompanying the report, Vermont Cancer Center researcher Hyman B. Muss, M.D., notes that targeted treatments such as Tykerb are major advances — and major expenses.

Muss suggests that when the new drugs offer a cure, they are well worth the expense.
But he questions whether they are worth the cost if they only delay disease progression for a few months, as was the case in this study.

"Currently, the greatest potential for these agents lies in their use as adjuvant therapy, before metastatic disease is evident, and when their addition to chemotherapeutic agents may improve the chance for a cure," Muss says.

Clinical trials — some now under way, some still in the planning stages — will test whether Tykerb and other new cancer drugs can be used earlier in the course of disease.

SOURCES: Geyer, C.E. The New England Journal of Medicine, Dec. 28, 2006; Vol. 355: pp. 2733-2743.

By Daniel DeNoon
Reviewed by Amal Chakraburtty