A total of 268 patients with metastatic breast cancer were prospectively randomized to receive Adriamycin-vincristine (AV) alone, AV plus dibromodulcitol (AVD), or AV plus ICRF-159 (AVI). Two hundred thirty were eligible and had received prior chemotherapy. The objective response rates were 27%, 23%, and 16% for AV, AVD and AVI, respectively, and an additional 44% had stabilization of disease. Duration of responses ranged from 4.1 to 4.6 months and the times to treatment failure from 2.9 to 3.8 months. Median survivals ranged from 7.1 to 8.3 months. Performance status and the presence of liver or brain metastases were significant prognostic variables for outcome. These studies show that AVI is inferior to AV with respect to survival when prognostic variables are taken into account in a multivariate model, whereas AVD which utilizes a lower dose of Adriamycin appears to have comparable antitumor activity to AV. This does not appear to offer any benefit to patients previously treated with chemotherapy, as in this trial, but it may be an advantage to previously untreated patients since Adriamycin can be administered to responding patients over a longer period of time before an unacceptable total cumulative dose is reached.