Long-term gemcitabine administration in heavily pretreated Japanese patients with metastatic breast cancer: additional safety analysis of a phase II study

Recently gemcitabine has been approved for treatment of metastatic or recurrent breast cancer in Japan; however, no systematically investigated safety study of long-term gemcitabine monotherapy has been reported despite its wide use globally for multiple indications. In a previously reported phase II study, 62 Japanese metastatic breast cancer patients with progressive disease after treatment with anthracyclines and taxanes were treated with gemcitabine 1250 mg/m(2) on days 1 and 8 of a 21-day cycle. For this report we re-analyzed the safety profiles for the 13 patients who received 10 or more cycles of the therapy. Most grade 3/4 adverse events seen after 10 cycles were hematological toxicities. These were similar to those seen before the 10th cycle; however, 2 patients showed grade 3 nonhematological severe adverse events including acute cardiac failure and loss of consciousness. All adverse events were reversible and manageable. One patient received gemcitabine treatment for up to 54 cycles without unmanageable toxicities. Toxicities seen in long-term gemcitabine treatment were reversible and manageable in this setting of heavily pretreated Japanese metastatic breast cancer patients.