Written by Amanda Gardner

Updated on June 12, 2022

TUESDAY, March 13, 2007 (HealthDay News) -- U.S. regulators approved on Tuesday a new drug that in clinical trials delayed breast cancer progression in women no longer responding to Herceptin, a drug effective against tumors with too much of a protein called HER-2.

When given in combination with chemotherapy, the new drug, Tykerb (lapatinib), did a better job of curtailing cancer growth than did the chemo drug alone.

"Today's approval is a step forward in making new treatments available for patients who have progression of their breast cancer after treatment with some of the most effective breast cancer therapies available," Dr. Steven Galson, director of the U.S. Food and Drug Administration's Center for Drug Evaluation and Research, said in a prepared statement. "New targeted therapies such as Tykerb are helping expand options for patients."

Tykerb, which comes in pill form, is made by GlaxoSmithKline, which funded the clinical trial. The results of the trial were initially announced last June at the American Society of Clinical Oncology annual meeting, in Atlanta.

About 8,000 to 10,000 American women die from metastatic HER2-positive breast cancer each year, the FDA said.

Tykerb, among a class of drugs called kinase inhibitors, deprives tumor cells of signals they need to grow. But it differs from other cancer drugs in that it actually enters cells and blocks the function of the HER2 protein, the agency said.

The drug was tested in a trial involving 400 women with advanced or metastatic breast cancer that was HER2 positive. Common side effects included diarrhea, nausea, vomiting, and rash. A small percentage of participants also had a decrease in heart function that may have been characterized by shortness of breath. This condition generally was reversible, the agency said.

Some 20 percent to 25 percent of breast cancers have abnormally high levels of the HER2/neu receptor and, as a result, are generally more aggressive. Herceptin (trastuzumab) blocks activity of the receptor by binding to the part of the receptor outside the cell. Tykerb, by contrast, binds to a part of the receptor inside the cell.

The clinical trial included a plan for an independent data monitoring committee to analyze data at the halfway point to see if the benefits were larger than anticipated, in which case the committee would recommend the study be closed.

On March 20, 2006, the monitoring committee made a unanimous recommendation to terminate the trial because the results were so encouraging.

Women in the combined therapy group had almost double the time to disease progression as did women receiving Xeloda alone: 36.9 weeks vs. 19.7 weeks.

Responding to the FDA's approval of Tykerb, Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society, said in a prepared statement: "The approval of Tykerb is a significant step forward because it once again demonstrates the promise of targeted therapies, where we take our understanding of how cancer cells work and apply that knowledge to new drug development. We now have a new drug that offers promise and hope to women who have a more aggressive form of breast cancer, where until very recently we had little to offer. And we now have two drugs that are effective in treating this particular form of the disease.

More information

To learn more, visit the U.S. National Cancer Institute.

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