ANN ARBOR A major reason that breast cancer returns after treatment and spreads to other parts of the body is that current chemotherapy and radiation treatments do not kill the cancer stem cells.

That premise provides the basis for a clinical trial open at the University of Michigan Comprehensive Cancer Center and two other sites testing a drug that has been found in laboratory studies to attack cancer stem cells. The drug, reparixin, will be used in combination with standard chemotherapy.

This is one of only a few trials testing stem cell directed therapies in combination with chemotherapy in breast cancer, says principal investigator Dr. Anne Schott, associate professor of internal medicine at the University of Michigan. Combining chemotherapy with stem cell therapy has the potential to lengthen remissions for women with advanced breast cancer.

Cancer stem cells are the small number of cells within a tumor that fuel its growth and spread.

The phase Ib study will test reparixin, which is taken orally, along with the chemotherapy drug paclitaxel in women with HER2-negative metastatic breast cancer. The study is primarily intended to test how patients tolerate this drug combination, but researchers will also look at how reparixin appears to be impacting markers for cancer stem cells and signs of inflammation. The study will also look at how effective this treatment combination is at controlling the cancer and impacting survival.

The clinical trial stems from laboratory research at U-M that identified a receptor called CXCR1 on the cancer stem cells that triggers growth of stem cells in response to inflammation and tissue damage. Adding reparixin to chemotherapy in laboratory studies specifically targeted and killed breast cancer stem cells by blocking CXCR1.

Mice treated with reparixin or the combination of reparixin and chemotherapy had dramatically fewer cancer stem cells than those treated with chemotherapy alone. In addition, reparixin-treated mice developed significantly fewer metastases than mice treated with chemotherapy alone.

FYI

According to the American Cancer Society, 234,580 Americans will be diagnosed with breast cancer this year and 40,030 will die from the disease.

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ANN ARBOR: University of Michigan breast cancer clinical trial looks at targeting cancer stem cells