Phase II study of liposomal annamycin in the treatment of doxorubicin-resistant breast cancer.

Liposomal annamycin (L-AN) has shown antitumor activity in preclinical studies. It may selectively target tumors and bypass MDR-1 resistance. A total of 13 women with doxorubicin-resistant breast cancer were treated on this phase II study. The median number of prior chemotherapy regimens was two, and six patients had two or more organ sites of involvement. L-AN was administered at 190-250 mg/m(2) as an i.v. infusion over 1-2 h every 3 weeks. No responses were observed. Of the 13 patients, 12 had clear deterioration and new tumor growth after one or two courses. The 13th patient had prolonged grade 2 thrombocytopenia after one course, and was taken off study when the lung metastases increased 62 days after treatment. L-AN at this dose and on this schedule had no detectable antitumor activity in patients with doxorubicin-resistant metastatic breast cancer.