Ifosfamide and mitoxantrone as first-line chemotherapy for metastatic breast cancer

A phase II trial was performed to evaluate the efficacy and toxicity of a combination of ifosfamide (IFX) and mitoxantrone (MXN) as first-line chemotherapy for metastatic breast carcinoma.

Between January 1990 and August 1991, 48 patients with metastatic breast cancer were entered onto the study. Therapy consisted of IFX 2 g/m2 given as a 1-hour intravenous (IV) infusion on days 1 to 3; mesna 400 mg/m2 as an IV bolus immediately before and 4 hours after IFX administration and 2,000 mg orally 8 hours after IFX administration on days 1 to 3; and MXN 12 mg/m2 as an i.v. bolus on day 3. Cycles were repeated every 21 days until progressive disease (PD) or severe toxicity developed.

One patient was considered not assessable for response. Objective regression (OR) was observed in 28 of 47 patients (60%; 95% confidence interval, 46% to 74%). Six patients (13%) had a complete response (CR) and 22 (47%) had a partial response (PR). The median time to treatment failure for the whole group was 9 months (range, 1 to 28); median survival was 19 months (range, 2 to 28). There were no treatment-related deaths. The limiting toxicity was myelosuppression. Leukopenia occurred in 37 patients (77%) and was grade 3 or 4 in 19 patients (40%). Nausea and vomiting were observed in 38 patients (80%), mucositis in 16 patients (33%), and grade 2 hematuria in two patients (4%). Eight patients (16%) developed mild neurotoxicity.

The combination of IFX plus MXN is an active regimen against metastatic breast cancer with moderate toxicity that deserves further evaluation.