Phase I/II study of dose-intense doxorubicin/paclitaxel/cyclophosphamide with peripheral blood progenitor cells and cytokine support in patients with metastatic breast cancer.

Relapse following complete remission achieved with a single course of high-dose chemotherapy continues to be the main cause of treatment failure in patients with metastatic breast cancer. A phase I/II trial was initiated that combined the two most active drugs against breast cancer, doxorubicin and paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), with cyclophosphamide, and delivered four cycles of these drugs with peripheral blood progenitor cells (PBPCs) and granulocyte colony-stimulating factor support in an outpatient setting. Patients with untreated metastatic breast cancer received two cycles of doxorubicin 60 mg/m2 and paclitaxel 200 mg/m2. During recovery from the second cycle, PBPCs were harvested. Responding patients were then admitted for a day to receive escalating-dose doxorubicin, paclitaxel, and cyclophosphamide followed by PBPC reinfusion on day 3 as outpatients. Seventeen patients have been enrolled to date. Ten patients completed treatment and received 34 cycles of high-dose chemotherapy every 21 days (range, 21 to 28 days). The median age was 47 years (range, 26 to 56 years) and the median number of metastatic sites was two (range, one to three). Five patients had received adjuvant chemotherapy (four cyclophosphamide/methotrexate/5-fluorouracil and one mitoxantrone-based). The most common toxic reactions were nausea and vomiting (75% of courses) and neurosensory (50% of courses). No patients had a decreased ejection fraction or overt congestive heart failure. Ten patients underwent cardiac biopsy (median doxorubicin, 253 mg/m2; range, 120 to 312 mg/m2); only one showed grade 1 cytotoxic changes with doxorubicin 240 mg/ m2. Six patients were admitted for neutropenic fever. Eight of 10 patients responded (two pathologically confirmed complete remissions in liver). At these doses, four cycles of doxorubicin, paclitaxel, and cyclophosphamide with PBPC and granulocyte colony-stimulating factor support every 21 days was well tolerated and showed evidence of activity. Enrollment at higher dose levels continues so that maximum tolerated dose can be defined.