High-dose epirubicin in combination with cyclophosphamide (HD-EC) in advanced breast cancer: final results of a dose finding study and phase II trial.

In the dose finding study we were able to demonstrate that an increase of the epirubicin dose to 120 mg/m2 in combination with cyclophosphamide (600 mg/m2) is possible. The phase II trial had to check the efficacy and the toxicity of this combination with a therapy interval of 21 days. 34 patients with metastatic breast cancer previously not treated with chemotherapy for metastatic disease entered this phase II trial, which tested the efficacy and toxicity of the chemotherapy combination epirubicin 120 mg/m2 and cyclophosphamide 600 mg/m2 (HD-EC regimen) i.v. every three weeks. Excluded from the trial were patients at risk of anthracycline toxicity and those with bone or brain metastases. Results compare favourably with best data reported in the literature for chemotherapy of metastatic breast cancer: overall remission rates of 73% (35% CR, 38% PR), median TTP of 58 weeks for CR (range 32-168 weeks) and 52 weeks for the PR group (range 24-110 weeks); median survival time for CR 71+ weeks (range 52-196+), for PR 74+ weeks (range 40-134+ weeks). No therapy was given for remission maintenance after a stable remission was obtained. This results in a very favourable ratio of time with chemotherapy to maintenance time without chemotherapy, which is 10 weeks/62 weeks for CR and 12 weeks/49 weeks for PR. Evidence of tumor remission was found in 80% of the patients who already responded to chemotherapy after the first cycle. The early onset of tumor response as well as the short induction chemotherapy period necessary to obtain best response are considered major advantages of the HD-EC regimen.