A phase II evaluation of combination chemotherapy plus aminoglutethimide in women with metastatic or recurrent breast carcinoma. An Eastern Cooperative Oncology Group Pilot Study.

The Eastern Cooperative Oncology Group (ECOG) conducted a pilot study of combination chemotherapy with cyclophosphamide, doxorubicin, and 5-fluorouracil plus aminoglutethimide (250 mg three times daily with hydrocortisone supplementation of 40 mg daily) as primary therapy for estrogen receptor-positive or unknown advanced breast carcinoma to assess whether these agents can be safely combined and to provide a preliminary estimate of response rate. A total of 47 patients, 45 with metastatic breast cancer and two with stage IV disease who were rendered clinically disease free following surgical resection of chest wall recurrence, were treated. Leukopenia and mucositis were the most frequent toxicities requiring dose reduction, but only five patients (10.6%; 95% confidence interval, 1.8-18.4%) experienced life-threatening leukopenia (less than 1000/mm3) at some point during their therapy. Neurologic side effects attributed to aminoglutethimide, predominantly lethargy, were reported in less than one-third of patients, and rarely required dose reduction. One elderly patient developed clinical hypothyroidism during the first 3 months on therapy and experienced a cardiac arrest at home while receiving supplemental thyroid hormones. The overall complete plus partial response rate in 45 patients was 55.5% (95% confidence interval, 41-70%). Among 16 patients with measurable disease, the complete plus partial response rate was 75% (95% confidence interval, 54-96%). The complete plus partial response rate in 29 patients with nonmeasurable but evaluable disease was 45% (95% confidence interval, 27-63%) and an additional 14% had improvement in bone pain. Eight patients electively discontinued chemotherapy after 7-24 months of therapy, but continued aminoglutethimide. The median time to disease progression is 462 days (15.4 months); 25% of patients died by 552 days (18.4 months), and the median duration of survival is predicted to be 889 days (29.6 months). We conclude that aminoglutethimide can be combined with this doxorubicin-based regimen with acceptable toxicity and an overall response rate which is similar to that observed on prior ECOG trials with cyclophosphamide, doxorubicin, and 5-fluorouracil.