Understanding Targeted Therapy in Breast Cancer

Posted on February 5th, 2009 by

Targeted therapies are anticancer drugs that are designed to treat cancer cells while minimizing damage to normal, healthy cells. These drugs, which may be used in the treatment of breast cancer, interfere with specific pathways involved in cancer cell growth or survival. Some targeted therapies block growth signals from reaching cancer cells; others reduce the blood supply to cancer cells; and still others stimulate the immune system to recognize and attack the cancer cell. Depending on the specific “target,” targeted therapies may slow cancer cell growth or increase cancer cell death.

Targeted therapies may be used in combination with other cancer treatments such as conventional chemotherapy.

Advances in science and technology have led to the development of several different types of targeted therapies, which target cancer through different mechanisms. These include targeted therapy for breast cancer.

Targeted Therapy for Breast Cancer

Herceptin® (trastuzumab) is a targeted therapy that binds to a protein known as the human epidermal growth factor receptor 2 (HER2). Twenty to thirty percent of breast cancers overexpress (make too much of) HER2, and could potentially respond to treatment with Herceptin. Results from an important clinical trial indicate that adding Herceptin to chemotherapy improves survival for patients with advanced HER2-positive breast cancer.[1] Herceptin has also been shown to improve survival among women with early-stage HER2-positive breast cancer that is node-positive or high-risk node-negative.[2] Among women with early-stage breast cancer, Herceptin is part of a treatment regimen that also includes chemotherapy.

Tykerb® (lapatinib) is FDA approved for the treatment of patients with advanced breast cancer that is HER2-positive and has progressed following therapy with chemotherapy agents known as taxanes and anthracyclines and the targeted therapy agent Herceptin. Tykerb is to be used in combination with the chemotherapy agent Xeloda® (capecitabine).  It works by blocking part of the epidermal growth factor receptor pathway and HER2, which are both involved in regulating cellular growth and replication; growth signals are thus inhibited.

Benefits of Targeted Therapy

By focusing their effects on specific characteristics of cancer cells, targeted therapies provide effective cancer treatment with fewer side effects than conventional chemotherapy. Because targeted therapies are generally well tolerated, they can often be combined with other cancer therapies such as chemotherapy in order to improve treatment effectiveness.

Risks of Targeted Therapy

Though targeted therapies tend to cause less damage to normal cells than conventional chemotherapy or radiation therapy, there are some potential side effects. Talk with your doctor or read the prescribing information for more complete information about potential side effects.

Learn Whether Targeted Therapy Is Right for You

Determining whether a specific targeted therapy is appropriate for your cancer requires consideration of many factors, including the type, stage, and previous treatment. In addition, the specific characteristics of your cancer may need to be evaluated.

References:

[1] Slamon DJ, Leyland-Jones B, Shak S, Fuchs H, Paton V, Bajamonde A, et al. Use of chemotherapy plus a monoclonal antibody against HER2 for metastatic breast cancer that overexpresses HER2. New England Journal of Medicine. 2001;344:783—792.

[2] Smith, I, Proctor M, Gelber RD et al. 2-year Follow-up of Trastuzumab after Adjuvant Chemotherapy in HER2-positive Breast Cancer: A Randomised Controlled Trial. Lancet. 2007;369:29-36.

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Tags: Breast Cancer

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