Healthcare Industry News: trastuzumab
News Release - December 18, 2006
Anthracyclines May Not Be for Everyone: Report From the 29th Annual San Antonio Breast Cancer SymposiumSAN ANTONIO, Dec. 18 (HSMN NewsFeed) -- The anthracycline drugs used as a standard component of chemotherapy for breast cancer patients (doxorubicin and epirubicin) may cause serious side effects, including heart damage. Women sometimes discontinue therapy, or avoid it altogether, because of anxiety about the effects of these drugs. Unfortunately, some patients will not respond to the drug, and will experience the often-devastating side effects in vain. Now a report from the 29th Annual San Antonio Breast Cancer Symposium suggests that there may be a straightforward way to predict who will respond to anthracycline drugs, based on a commonly measured tumor marker.
Multiple clinical trials have demonstrated reduced rates of cancer recurrence and increased overall survival in patients receiving anthracycline- containing regimens compared with those receiving cyclophosphamide, methotrexate, and 5-fluorouracil (CMF), another commonly used combination drug regimen.
At the Sunday morning General Session of the Symposium, Alessandra Gennari, MD, from the National Cancer Research Institute in Genoa, Italy, presented her research on the interaction between HER2 status and response to chemotherapy containing anthracycline drugs. HER2 is a protein that is found on the surface of cells, and in some patients is related to the uncontrolled growth of tumors. HER2 is the target of trastuzumab, a targeted therapy that has been used in some breast cancer patients.
An interaction between HER2 status and response to doxorubicin has been reported in some studies, but not in others. There have been differences in patient populations, differences in how HER2 is measured, and other differences that make these studies difficult to compare. A major problem has been that many of these studies enrolled too few patients, making it difficult to determine if small or moderate variances are important, or if they are just due to chance. Larger studies can be conducted, but they are extremely expensive, and frequently take many years to accrue enough patients.
Dr. Gennari and colleagues approached this problem by using a meta- analytic approach to combine the results of published studies. Meta-analysis is a powerful statistical technique that takes data from multiple studies and combines them in one large "virtual" clinical trial. Since first introduced by Sir Richard Peto in the 1970s, meta-analysis has become a widely used tool to enable researchers to use data that are already available to answer clinically important questions.
Dr. Gennari identified several published studies that used anthracycline- containing chemotherapeutic regimens and recorded patients' HER2 status. Considered individually, these studies reported contradictory results. For disease-free survival, a measure of how soon cancer recurs, two of these studies showed that HER2 status had a significant impact on response to anthracyclines, one showed a borderline interaction, three showed no interaction, and one did not measure disease-free survival. A similar picture was seen for overall survival.
When the studies were combined in the meta-analysis, however, anthracycline treatment was associated with a 29% decrease in risk of relapse and a 27% decrease in risk of death in HER2-positive patients, but had no effect on outcomes in HER2-negative patients.
Because HER2 status is now commonly measured in most women with breast cancer, this breakthrough finding, if substantiated, will provide a powerful new tool to help the patient and her physician make the best possible choice of treatment.
Source: San Antonio Breast Cancer Symposium
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