The purpose of this trial was to study feasibility and tolerance of a dose-intensive multicyclic alternating induction chemotherapy with repeated stem cell support in a series of 43 metastatic breast cancer patients. Anthracycline-naive patients (n = 21) received cyclophosphamide 2.5 g/m(2) plus doxorubicin 80 mg/m(2) alternating every 14 days with paclitaxel 200-350 mg/m(2) plus cisplatin 120 mg/m(2). Patients who had previously received anthracyclines (n = 22) received cisplatin 120 mg/m(2) plus etoposide 600 mg/m(2) alternating with paclitaxel 200-350 mg/m(2) plus ifosfamide 8 g/m(2). Peripheral blood stem cells were infused after every course except the first, with a median CD34(+) dose of 2.1 x 10(6)/kg per cycle. Positive selection of CD34(+) cells was performed in good mobilizers. The median number of cycles administered was six (4-8), and the time interval between them was 17 days. Median summation dose intensities (SDI) actually administered for the CA-TP and PE-TI protocol were 4.95 and 4.69, respectively (87% of scheduled SDI). There were 15 complete (35%) and 21 partial responses (49%), for an overall response rate of 84% (95% CI, 73%-95%). Infection or neutropenic fever occurred in 50% of the cycles. There was one treatment-related death. After a median follow-up of 26 months, the median event-free-survival was 12 months (95% CI: 10-14) and overall survival was 31 months. These high dose-intensity induction treatments seem to be feasible with sequential stem cell support.