(RxWiki News) HER2 is a protein that can be overexpressed in breast cancer, causing an aggressive disease. While there are treatments that target HER2, this form of cancer is tenacious. Scientists have found a new treatment option for this type of breast cancer.
An international phase III clinical trial has found that Kadcyla (trastuzumab emtansine; T-DM1) helped women with advanced HER2-positive breast cancer live longer.
The women in the study had previously undergone a number a different treatment regimens.
The trial found that T-DM1 doubled the length of time before the disease got worse – progression-free survival (PFS).
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Professor Hans Wildiers, adjunct head of clinic, medical oncologist and coordinator of the chemotherapy and related clinical trial programme in the multidisciplinary breast centre at the University Hospitals Leuven, Belgium, led the study that looked at the benefit T-DM1 offered to women who had undergone two or more treatments for their disease.
T-DM1 is a combination drug made up of trastuzumab (Herceptin) combined with DM1 to target and kill HER2-positive breast cancer cells.
Kadcyla was approved by the US Food and Drug Administration in February 2013 to treat HER2-positive breast cancer patients previously treated with Herceptin and taxane chemotherapy agents – Taxotere (docetaxel) and Taxol (paclitaxel).
This study looked at women whose cancer had spread (metastasized) to internal organs after being treated with several regimens, including Herceptin and Tykerb (lapatinib), which is used to treat metastatic breast cancer.
A total of 602 HER2-positive breast cancer patients were randomly assigned to receive either T-DM1 every three weeks or a treatment of their physician’s choice.
Most (75 percent) of the women had cancer that had spread to internal organs and had previously received a median of four different regimens.
Women who were given the T-DM1 had a median progression-free survival of 6.2 months compared to 3.3 months for women in the other group, who were able to cross over to T-DM1 after their disease progressed.
Of the women in the T-DM1 group, 31.3 percent responded to the drug, while 8.6 percent of the women responded to their physician’s treatment choice.
Interim analyses could not confirm overall survival benefits for T-DM1.
The women in the T-DM1 group generally had fewer serious adverse side effects than women in the other group.
Findings from this study are to be presented at the 2013 European Cancer Congress (ECC2013).
"The data from this trial reaffirms the benefits and lack of severe toxicity of T-DM1 in most women with advanced, progressive HER2-positive metastatic breast cancer,” Adam Brufsky, MD, PhD, professor of medicine at the University of Pittsburgh, told dailyRx News.
Prof Wildiers added in a prepared statement, “T-DM1 has the potential to be a new treatment paradigm for this group of patients who currently have few options."
This study was funded by Roche, the manufacturer of Kadcyla.
Several of the authors reported financial ties with Roche and other pharmaceutical manufacturers.