Serious heart problems, including ventricular dysfunction and congestive heart failure, have been reported as side effects in a small number of breast cancer patients receiving trastuzumab (the generic name for Herceptin) alone or in combination with chemotherapy.
An estimated10% of patients taking trastuzumab have experienced significant decreases in heart function. Furthermore, 1.7% to 4.1% of patients taking trastuzumab have experienced heart failure.[1]
In the past, cardiac side effects were observed in patients receiving trastuzumab either after chemotherapy with an anthracycline (such as doxorubicin) or in combination with an anthracycline drug. Typical courses of a combination of trastuzumab and an anthracycline drug are administered during a period of 1 to 2 years. The anthracycline class of chemotherapeutic drugs is known to have potential cardiac side effects.
Heart failure is more common among breast cancer patients who receive trastuzumab in combination with the AC chemotherapy regimen; i.e., chemotherapy consisting of an anthracycline, such as Adriamycin (doxorubicin) or Ellence, and cyclophosphamide). However, trastuzumab is not approved for use with the AC chemotherapy combination outside of a clinical trial setting.
A recent small study of trastuzumab therapy given before exposure to any other potentially cardiotoxic treatments shows that 9 weeks of a combination of trastuzumab therapy and chemotherapy was effective treatment for breast cancer and did not result in cardiac failure in any of the 116 patients treated.[1, 2] Moreover, the patients treated with trastuzumab and chemotherapy exhibited fewer reductions in heart function than did patients treated with chemotherapy alone. However, the shorter course of trastuzumab therapy has not been approved by regulatory agencies.
Women considering trastuzumab as treatment for breast cancer should have their heart function evaluated by a doctor before beginning treatment. Once on trastuzumab, women should be closely monitored by their doctor for any heart problems that may occur.
REFERENCES
1. B. Robinson. NCI Cancer Bulletin. New trastuzumab regimen lessens cardiac side effects. 2006; 3(9):1-2.
2. H. Joensuu et al. New England Journal of Medicine. 02/23/06.
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