Neratinib useful for breast cancer regardless of trastuzumab use

NEW YORK (Reuters Health) - Neratinib, an irreversible ErbB receptor tyrosine kinase inhibitor, is beneficial for advanced ErbB2-positive breast cancer regardless of whether trastuzumab has been used in the past, researchers report in the February 8th online issue of the Journal of Clinical Oncology.

"We demonstrated that neratinib has substantial clinical activity in each group, with robust response rates and durable periods of tumor control," Dr. Harold J. Burstein of the Dana-Farber Cancer Institute, Boston, told Reuters Health by e-mail. "We think these results establish neratinib as an active agent for patients with HER2-positive breast cancer."

Participants in the open-label, phase 2 study, recruited in six countries, all had stage IIIB, IIIC or IV breast cancer not curable with available therapy. One group of 66 had been treated with trastuzumab (median 14.3 months), and a parallel group of 70 had not. Patients received daily oral doses of neratinib 240 mg.

Sixteen-week progression-free survival rates were 59% in patients with previous trastuzumab therapy and 78% in those with no such prior therapy. Median progression-free survival times were 22.3 and 39.6 weeks, respectively.

The rates of objective (complete or partial) response were 24% in patients with earlier trastuzumab treatment and 56% in those without.

The only grade 3 or 4 adverse event to occur in more than 10% of participants was diarrhea. Side effects were generally mild or moderate and easily managed. There was no evidence that left ventricular ejection fraction was impaired by neratinib treatment in either group.

The study was funded by Wyeth Research, which makes neratinib.

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