Induction chemotherapy of dibromodulcitol, adriamycin®, vincristine, tamoxifen, and halotestin® with methotrexate in metastatic breast cancer: An eastern cooperative oncology group study (E1181)

Patients who have metastatic breast cancer are seldom curable. Chemotherapy given by conventional doses and schedules generally produces complete remissions in 10% to 20% of patients. This study sought to determine 1) whether a combination of dibromodulcitol, Adriamycin[R], vincristine, tamoxifen, Halotestin[R], and methotrexate with leucovorin rescue (DAVTHML) can produce a complete remission rate of 50%; and 2) the toxicity of this combination in patients with chemotherapy-naive metastatic breast cancer. Patients were treated with six 28-day cycles of DAVTHML induction chemotherapy consisting of dibromodulcitol, 135 mg/m² perorally days 1 to 10; Adriamycin[R]m 45 mg/m² intravenously day 1; vincristine, 2 mg intravenously day 1; tamoxifen and Halotestin[R], 20 mg perorally daily; methotrexate, 800 mg/m² intravenously days 15 and 22; and leucovorin, 15 mg/m² perorally every 6 hours for 9 doses, starting 4 hours after methotrexate. After induction, patients who had stable disease or a partial response were treated with a cyclophosphamide, methotrexate, and 5- fluorouracil-based regimen (CMF). Patients in complete remission were treated with three additional cycles of DAVTHML after achieving complete remission and then observed off therapy until relapse, when DAVTHML was to be given again. Fifty-eight patients were included in this study. During induction, 26% of eligible patients experienced a complete remission; overall response rate was 80%. The median time to treatment failure and the median survival time of eligible patients was 11.1 and 24.0 months, respectively. This did not change significantly when all the patients were included in the evaluation. The 3-year and 5-year survival rates were 37% and 11%, respectively. Ninety percent of the eligible patients experienced grade III or IV toxicity. They were leukopenia (75%), anemia (20%), thrombocytopenia (20%), and vomiting (17%). No lethal toxicity was documented during therapy; however, I patient later died of myelodysplastic syndrome induced by dibromodulcitol. The overall response and complete remission rates from our study were encouraging. The toxicity of DAVTHML was tolerable, with the exception of myelodysplastic syndrome from dibromodulcitol. The concept of using mid-cycle nonmyelosuppressant agents to increase complete remission rate is feasible.