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Study Shows Drug May Still Help Breast Cancer Patients Years After Ending Treatment
By Salynn Boyles
WebMD Health News
Reviewed by Laura J. Martin, MD
Feb. 24, 2011 -- High-risk breast cancer patients continue to derive benefits from the drug Herceptin even four years after stopping treatment, but questions remain about the biologic therapy's safety when given with chemotherapy.
Newly reported follow-up data from a large international study show that women with early-stage HER2-positive breast tumors who took Herceptin for one year are 24% less likely to have their tumors return after four years than women who did not take the drug.
Overall survival was no better for patients treated with the biologic therapy than for patients who received chemotherapy alone. But researchers attribute this to the fact that women who originally did not take the drug were allowed to cross over into the active-treatment part of the study based on the strength of the early findings.
About one in five breast cancers are HER2 positive, which tend to be more aggressive and difficult to treat than other breast cancers.
4-Year Outcomes Still Encouraging
The Herceptin Adjuvant (HERA) international study included more than 5,000 women with HER2-positive, early-stage breast cancers enrolled between December 2001 and June 2005.
The original study design called for the women to receive either standard chemotherapy alone, chemotherapy followed by one year of Herceptin, or chemotherapy followed by two years on the biologic drug.
One-year follow-up data from the study, reported in 2005, show an almost 50% reduction in disease recurrences in women treated with the drug for a year.
The latest findings confirm that treatment with Herceptin following chemotherapy has long-term benefits for women with early stage HER2-positive tumors, says study researcher Luca Gianni, MD, of Milan Italy's San Raffaele Institute.
He adds that findings from the two-year treatment part of the study should be reported later this year or early next year.
The latest results from the ongoing study are published in the Feb. 25 issue of The Lancet.
"We can't say this yet, but it may be that treatment for longer than one year is optimal," Gianni tells WebMD.
Questions Remain About Treatment Timing
Breast cancer specialist Edith Perez, MD, of the Mayo Clinic Florida, says it remains to be seen if treatment longer or shorter than a year is optimal.
Herceptin is expensive, costing around $50,000 or more per year, and it is given by intravenous injection.
"With cost-effectiveness and patient convenience in mind, there is a lot of attention on how long to give this drug," Perez tells WebMD. "It may be that two years is better than one, but it may also be that three months is better than two years."
Treatment duration is just one of the unresolved issues surrounding the use of Herceptin in breast cancer.
In the HERA study, patients were treated with the drug following chemotherapy. But in other studies it has been given along with chemotherapy.
Several studies, including one led by Perez, have suggested that concurrent treatment may be most effective. But serious and even life-threatening heart problems have been reported in patients who took the drug with the chemotherapy drug anthracycline.
In an editorial published with the HERA data, a group of European researchers questioned the safety of giving the two drugs together.
In the U.S., Herceptin is usually given during chemotherapy but after anthracycline has been discontinued, Perez says.
She says heart problems have been very rare with this approach and were reversible when they did occur in the vast majority of cases.
"Questions remain about how to use [Herceptin]," she says. "But in terms of the management of patients with breast cancer, this is the most important drug we have seen in the last 15 years in term of changing outcomes."
Herceptin is marketed by Genentech, which contributed funding for the HERA trial.
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