Randomized clinical trial of doxorubicin alone or combined with mitolactol in women with advanced breast cancer and prior chemotherapy exposure

One hundred fifty-one women with advanced breast cancer who had failed prior chemotherapy were randomized to monthly courses of doxorubicin (60 mg/m² I.V. day 1, observation after 500 mg/m²) or doxorubicin (40 mg/m² I.V. day 1; maximum 500 mg/m²) and mitolactol (135 mg/m² orally, days 1-10; 180 mg/m² after maximum doxorubicin). Median survival times were 232 days for doxorubicin and 225 days for doxorubicin + mitolactol, and median time to progression were 112 days and 97 days, respectively. Results are inconsistent with a 25% improvement in survival or time to progression for doxorubicin + mitolactol (p = 0.04 and 0.02, respectively, adjusted for stratification factors but not multiple testing). Regression rates for all patients, both measurable and evaluable, were 30% for doxorubicin alone and 26% for doxorubicin + mitolactol. Regression rates were significantly higher in patients with measurable indicator lesions. Cardiac toxicity was seen in four patients, all of whom were receiving doxorubicin alone. It appears that the combination of doxorubicin + mitolactol is not substantially more effective than doxorubicin alone in women with advanced breast cancer and prior chemotherapy exposure.