FDA Expands Use of Breast Cancer Drug, Tykreb
The U.S. Food and Drug Administration (FDA) has approved the expanded use of the breast cancer drug Tykerb (generic name, lapatinib) for diagnosed with a certain type of the disease. The approval allows physicians to prescribe Tykreb, along with another drug, Femara (generic name, letrozole), to treat women whose advanced breast cancers have extra copies of the HER2 protein (so-called “HER2 positive†breast cancer).
HER2 is a protein found on the surface of cells that, when functioning normally, has been found to be a key component in regulating cell growth. However, when the HER2 protein is altered, extra HER2 protein receptors may be produced. This over-expression of HER2 causes increased cell growth and reproduction, often resulting in more aggressive breast cancer cells. HER2 protein over-expression affects approximately 20% to 30% of breast cancer patients. Women with HER2 over-expression may not be as responsive to standard breast cancer treatments, including certain regimens of chemotherapy.
Herceptin and Tykerb are two drugs that may be used to treat breast cancer in these breast cancer patients, in combination with other breast cancer treatments. Herceptin was FDA-approved in September 1998 and has shown promise in increasing patient survival time and reducing the number of deaths from advanced breast cancer. Clinical trials are also investigating whether Herceptin is helpful for women with early-stage breast cancers. Tykerb was approved in 2007 to treat advanced breast cancer in combination with the chemotherapy drug, Xeloda (generic name, capectabine). According to the FDA, Tykerb works by depriving tumor cells of signals needed to grow. Tykerb enters the cell and blocks the function of the HER2 protein.
In research leading to the FDA's expanded approval of Tykreb, women with HER2-positive disease receiving the Tykerb plus Femara combination more than doubled the time they lived without the cancer progressing compared with those receiving Femara alone (35 weeks vs. 13 weeks). However, according to the FDA, it is too early to determine whether an improvement in overall survival will be observed in the clinical trial.
"This drug combination of Tykerb plus Femara provides women being treated for advanced breast cancer with an important treatment option. This entirely oral treatment regimen works by targeting both HER2 and the hormone receptors, thereby slowing the cancer cell's ability to grow or spread," stated Richard Pazdur, M.D., director of the Office of Oncology Drug Products, in the FDA's Center for Drug Evaluation and Research.
According to the FDA, safety information from the recent study was consistent with previous Tykerb clinical studies in advanced breast cancer. Common side effects of the Tykreb/Femara combination were diarrhea, rash, nausea and fatigue.Treatment with Tykerb also has been associated with decreases in heart function, liver damage, and lung tissue inflammation. Fetal harm may occur if used to treat advanced breast cancer in pregnant women. Patients are encouraged talk to their health care providers about potential side effects, drug interactions, and other medical conditions.
Additional Resources and References
- The FDA news release, "FDA Expands Use of Approved Breast Cancer Drug," was published on the FDA's web site, http://www.fda.gov/
- To learn more about HER2, Tykreb, and Herceptin, please visit http://www.imaginis.com/breasthealth/herceptin.asp
