• 2009 Turning Point

    Clinical trials for new HER2-positive breast cancer therapies

    Eric WinerEric Winer, MD 

    The success, and limitations, of trastuzumab for HER2-positive breast cancer have inspired the creation of a series of novel drugs. Investigators in the Women's Cancers Program (WCP) are leading or offering clinical trials of five classes of these new therapies.

    They include:

    • Agents similar to the drug lapatinib (brand name Tykerb) that latches onto a different portion of the HER2 receptor than does trastuzumab.
    • A compound known as TDM1 that hitches a chemotherapy agent to a specific antibody. By gravitating toward HER2-positive breast cancer cells, the antibody makes a "special delivery" of chemotherapy directly to them.
    • Agents that block or inhibit a protein known as HSP90. HSP90 is a "chaperone" protein that enables the HER2 receptor to function better. Inhibiting HSP90 offers a promising, if indirect, way to disable HER2.
    • Angiogenesis inhibitors that may block the growth of blood vessels that help feed tumors the nutrients they need to grow.

    Finally, studies are planned with pertuzimab, a "monoclonal" antibody (an antibody duplicated millions of times over) that prevents the HER2 receptor from joining to its sister receptors HER1 and HER3. Without such a connection, HER2 cannot activate cell growth.

    "In cases of advanced HER2-positive breast cancer, these potential therapies may provide great hope for women whose cancer is resistant to trastuzumab," says Eric Winer, MD, director of the Breast Oncology Center within the WCP. "For women with early breast tumors, they may offer an increased number of options if the disease progresses."

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