Doxorubicin, either as a single agent or in combination regimens, is considered to be one of the most active chemotherapeutic agents in the treatment of metastatic breast cancer. However, its clinical utility is limited by a cumulative, dose-dependent cardiac myopathy that can lead to potentially fatal congestive heart failure. Considerable research has gone into improving the therapeutic index of doxorubicin-based regimens. A new liposomal formulation of doxorubicin (Myocet, Elan Pharmaceuticals) has a significantly improved therapeutic index compared with conventional doxorubicin. The development of Myocet, a less cardiotoxic, better tolerated and equally efficacious doxorubicin, extends the therapeutic options in the overall management of breast cancer.