Gemcitabine plus dose-escalated epirubicin in advanced breast cancer: results of a phase I study
Gemcitabine has shown single-agent activity in metastatic breast cancer. Epirubicin is also widely used for the adjuvant and treatment of metastatic breast cancer. The toxicity profiles and modes of action are different which provides a good rationale for studying both drugs in combination. In a phase I study gemcitabine at a fixed dose of 1000 mg/m2 on days 1, 8, 15 of a 28 day cycle was combined with escalated weekly doses of epirubicin starting with an initial dose of 10 mg/m2. Patients had stage IV metastatic disease without previous chemotherapy except as adjuvant treatment. Nineteen patients were included in the study which defined the maximum tolerated dose (MTD) of epirubicin at 20 mg/m2. Myelosuppression was the dose limiting toxicity with leucopenia WHO grade 3 and 4 in 40.0% and 20.0%, neutropenia WHO grade 3 and 4 without neutropenic fever in 20.0% and 40.0% and thrombocytopenia WHO grade 4 in 20.0%. At the epirubicin 15 mg/m2 dose level, leucopenia (11.1% WHO grade 3) and neutropenia (12.5 and 37.5% WHO grade 3 and 4) were reported. Symptomatic toxicity was generally mild: nausea/vomiting in about 20% of patients (WHO grade 3 or 4) on both 15 and 20 mg/m2 epirubicin dose levels. Alopecia WHO grade 3 and 4 was seen in 2 patients at MTD. Four of 19 evaluable patients had a partial response. We conclude that the combination of gemcitabine and epirubicin is well tolerated and has promising activity. A phase II study is underway with gemcitabine 1000 mg/m2 and epirubicin 15 mg/m2 on days 1, 8 and 15 of a 28 day cycle.