A Trial of Standard Chemotherapy With Metformin (vs Placebo) in Women With Metastatic Breast Cancer

"metformin 850 mg bid in addition to standard chemotherapy (containing anthracyclines, platinum, taxanes or capecitabine; first or second line).~Number of cycles: Until progression or unacceptable toxicity develops."

"Placebo bid in addition to standard chemotherapy (containing anthracyclines, platinum, taxanes or capecitabine; first or second line).~Number of cycles: until progression or unacceptable toxicity develops."