Pemetrexed (Alimta) and gemcitabine in breast cancer patients previously treated with anthracyclines and taxanes.

Gemcitabine (2',2'-difluorodeoxycytidine) is a pyrimidine antimetabolite with broad activity in a variety of solid tumors including breast cancer. Pemetrexed (Alimta) is a novel, multitargeted antifolate that inhibits 3 folate-dependent enzymes, and is also broadly active in a wide variety of solid tumors. In breast cancer, pemetrexed has activity in patients previously treated with anthracyclines and taxanes, and pemetrexed demonstrates preclinical and clinical cytotoxic synergy with gemcitabine. This drug combination is being evaluated in a phase II study for the treatment of metastatic breast cancer patients who have previously received a taxane and an anthracycline.