Thirty elderly (over 70 years) women with measurable advanced breast cancer entered into this Phase II study. An initial dose of 30 mg/m2 of pirarubicin (THP) every 3 weeks was given intravenously. THP was escalated by levels of 10 mg/m2 according to the blood cell count done at day 14 and day 21 until a maximum dose per cycle of 70 mg/m2 was reached. The mean total cumulative dose of THP received was 204 mg/m2 (range 30-710 mg/m2). The mean number of cycles given was 5.5 (range 1-24). Of 28 evaluable patients, 1 achieved a complete response (CR), 6 had a partial response (PR) (CR + PR = 25%; 95% confidence interval 9-41%), 13 showed no change, and 5 had a progressive disease. The median time to progression was 3 months (range 0.5-18+ months). Of 28 patients evaluable for toxicity, the hematologic toxicity at day 15 was neutropenia grade 3 and 4 in 61% of the patients and thrombopenia grade 3 and 4, 0% of cycles. No cumulative hematologic toxicity was detected. Nonhematologic toxicities consisted of nausea and vomiting in 50% of patients (WHO grade 3 = 5%) and alopecia in 64% (WHO grade 2-3 = 36%). No stomatitis occurred. No cardiac toxicity was observed. The results of this study show that THP is an active drug in elderly patients with advanced breast cancer. Because of its safety, THP deserves further investigation in this application.