Background: In vitro data demonstrated a dose-response relationship for doxorubicin in ovarian cancer (OC) cell lines. However, this dose-response question for doxorubicin was never carefully addressed in OC patients. These data and the more favorable toxicity profile of the anthracycline analogue epirubicin prompted us to study high-dose epirubicin (HDE) in relapsed OC patients. Patients and Methods: This phase I study included 19 OC patients with measurable or evaluable disease and no more than one prior (cisplatin-containing) chemotherapy regimen. Dose escalation was not allowed in individual patients. Epirubicin was administered by rapid intravenous infusion (<5 min) once every 3 weeks and studied at the following dose levels: 120, 135, 150, 180 and 200 mg/m(2) (at least 3 patients per dose level). None of the patients received hematopoietic growth factors. We defined the maximum tolerated dose (MTD) as the dose at which we observed WHO grade 4 hematologic toxicity in greater than or equal to 50% and/or WHO grade 3 nonhematologic toxicity in greater than or equal to 30% of the patients. Results:The MTD was 200 mg/m(2), with DLT being both hematologic (leukopenia and/or thrombocytopenia) and nonhematologic (mucositis). Objective responses were observed in 6 patients (response rate 32%), 3 of them occurring in 10 patients with primary platinum resistance. Conclusions: HDE is tolerable and has activity in second-line after cisplatin-based chemotherapy in OC patients. The recommended dose for phase II trials in such patients is 150 mg/m(2), with escalation to 180 mg/m(2) if toxicity permits.