Role of gemcitabine in metastatic breast cancer patients: a short review.

Many active cytotoxic drugs, given according to a number of different regimens are approved for the treatment of metastatic breast cancer patients. However, these therapies have not changed the outcome of patients affected by this malignancy. As a consequence, the balance between chemotherapy-induced side effects and relief of cancer-related symptoms must be carefully considered in this setting. Gemcitabine is an antimetabolite that is incorporated as a triphosphate into DNA. As a single agent, it yields responses rates ranging from 14% to 37% in chemotherapy-naïve patients and from 12% to 30% in patients previously treated with anthracyclines and/or taxanes. In combination with paclitaxel, it produces a significantly higher response rate (41.4% vs. 26.2%), longer time to progression (6.1 vs. 4 months) and significantly higher overall survival (18.6 vs. 15.8 months) than paclitaxel alone. In addition, a phase III study revealed that gemcitabine plus docetaxel is as effective as capecitabine plus docetaxel, but causes significantly less non-haematologic toxicity. Lastly, in another phase III trial, progression free survival was significantly longer with the combination of gemcitabine plus vinorelbine than with vinorelbine alone (6 vs. 4 months), but without a significant difference in overall survival; the incidence of haematologic toxicity was higher in the group treated with combined therapy. Novel gemcitabine combinations are being investigated in phase II studies.