The combination of Navelbine® injection, a chemotherapy treatment used for advanced non-small cell lung cancer, and Herceptin®, an antibody therapy, is a promising and well-tolerated treatment for HER2 positive metastatic breast cancer, according to the results of a study published in The Oncologist.

U.S. researchers designed the study to determine if the addition of Navelbine would increase the expected response rate to Herceptin therapy without significantly increasing serious side effects.

The study included 40 women with metastatic breast cancer whose tumors over-expressed the HER2Neu oncogene, a growth-promoting protein that has been linked to a poor outcome in women with breast cancer and who were therefore candidates for therapy with Herceptin.

Weekly intravenous doses of Herceptin and Navelbine were given over four-week courses. Thirty-seven patients were evaluated for a response after receiving at least two courses of treatment. A total of four complete responses and 25 partial responses were seen for an overall response rate of 78 percent. Average time to disease progression (when patients show a worsening of their disease) was 17 months.

The most frequent but reversible side effect of the treatment was neutropenia, which is a reduction in infection-fighting white blood cells.

Researchers report that the combination of Navelbine and Herceptin appeared to improve overall response rates up to three-fold compared to historical data on either drug used alone. This combination, according to the researchers, extended the time to disease progression beyond that shown in single-drug studies of Herceptin.

Based on the results of this study, a randomized Phase III multicenter trial of the combination is currently being conducted.

Navelbine (vinorelbine tartrate) is not currently approved for use in women with metastatic breast cancer except as a study medication.

Other sources: GlaxoSmithKline