In a retrospective case-control study of patients with HER2-positive breast cancer that had spread, the team compared overall survival and progression-free survival between a group of 37 patients who received trastuzumab plus chemotherapy and recombinant erythropoietin to a matched control group of 74 whose cancer was treated the same way but who received no EPO.

A statistically significant difference in progression-free survival emerged at one year, with 40 percent of the control group having stable disease compared with 19 percent of the erythropoietin group. Overall progression-free survival differences across two years were not statistically significant.

The control group also had better overall survival than the erythropoietin group that was statistically significant in an analysis of multiple variables.

Fan emphasized that clinical findings should be interpreted with caution because the study was small and retrospective. Patients who received erythropoietin might have been sicker than the patients not treated with erythropoietin. Their findings need to be confirmed by larger clinical studies.

"We're expanding this study to include other types of cancer," Fan said. "Of course, different types of cancers are treated with different types of targeted therapies. We need to design our studies using different targeting agents than Herceptin to study whether erythropoietin can antagonize these drugs," Fan said.

Looking forward, Fan said, researchers need to find out why and how some cancer cells express the receptor protein for erythropoietin, and to what extent cancer cells express EpoR. "Recombinant erythropoietin helps to improve a patient's general condition without the need for a blood transfusion," Fan said. "If we can figure out how the expression of the erythropoietin receptor is regulated in cancer cells, we may come up with some new strategies to allow cancer patients to receive the drug for their anemia and fatigue without compromising their treatment with novel targeted therapies, such as anti-HER2 therapy with Herceptin."

Source: University of Texas MD Anderson Cancer Center