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Diabetes Drug Metformin Increases Survival in Ovarian Cancer Patients
Several recent studies have suggested that metformin, an established drug developed to treat patients with type-2 diabetes, may provide significant benefits, including increased survival, in patients with advanced cancers. An analysis of combined results from these earlier studies found that the use of metformin was associated with a significant decrease in cancer risk, tumor burden, and cancer mortality.
Researchers at the University of Chicago Medicine are leading a clinical trial that will compare the most effective current therapy for patients with stage-3 or -4 ovarian cancer compared with the same therapy plus metformin. To enroll in the study, volunteers must have a presumed or confirmed diagnosis of ovarian, fallopian tube, or primary peritoneal carcinoma, but not diabetes.
“This is the first study of its kind in ovarian cancer,” said trial director Diane Yamada, MD. “We think this is an exciting opportunity to find out if a safe, well-tested, and inexpensive drug can significantly improve on our best current therapy. There is a strong biological rationale, a series of consistently encouraging results from observational studies, and a real need for better, cost-effective therapies for this type of cancer.”
Studies performed at the University of Chicago and at the Mayo Clinic have independently found that ovarian cancer patients who happened to be taking metformin for their diabetes while going through cancer treatment had significantly better outcomes. In the Chicago study, 63% of patients taking metformin for their diabetes were alive 5 years later, compared with 37% of patients who did not have diabetes and 23% of patients who had diabetes but were not taking metformin.
Ovarian cancer has the highest fatality rate of all of the gynecologic malignancies. Although more than 80% of patients initially respond to treatment, most women with advanced disease experience recurrence.
Laboratory studies suggest that metformin can inhibit tumor growth, alter the interaction between cancer cells and their immediate environment, and make tumor cells more sensitive to the chemotherapy used to treat advanced ovarian cancers.
Standard care for advanced ovarian cancer consists of carboplatin plus either paclitaxel or docetaxel and surgery to remove as much of the disease as possible.
In the new study, half of the patients will receive chemotherapy plus twice-daily metformin. The other half will receive placebo. Once the chemotherapy has been completed, the patients will continue to take metformin or placebo as maintenance therapy for an extended period.
The medications being tested have been used extensively in ovarian cancer patients. They all cause adverse events (AEs). For example, carboplatin is associated with fatigue, infections, and reduced blood-cell counts. Paclitaxel causes AEs similar to those of carboplatin, along with allergic reactions, neuropathy, and hair loss. The AE profile of docetaxel includes fluid retention.
Metformin causes fewer and milder AEs compared with these anticancer drugs, but its use can result in indigestion, bloating, liver dysfunction, and anemia. People with certain health problems, such as congestive heart failure or excessive alcohol use, cannot take metformin because of an increased risk of lactic acidosis.
The researchers hope to enroll a total of 160 patients.
Source: University of Chicago; May 20, 2015.