Bisantrene, an active drug in patients with advanced breast cancer.

We have previously reported that bisantrene has significant activity against a variety of tumors in the human tumor soft agar cloning assay. An update of that experience reveals that 26% of evaluable human breast cancer specimens were sensitive to bisantrene, which had activity equivalent or superior to that of doxorubicin. Because of the preclinical activity of bisantrene and its activity in the cloning assay, bisantrene was studied in a phase II clinical trial of 30 patients with advanced breast cancer refractory to standard agents. Six patients (20%) had objective complete or partial regressions, including one patient with complete regression of lymphangitic lung metastases lasting greater than 18 months, confirming the antitumor activity of this compound. Two of the six responding patients had failed doxorubicin treatment, implying a lack of complete cross-resistance. Bisantrene toxicity was acceptable in most patients, with reversible myelosuppression being the most frequent side effect. Phase III trials of this promising new agent are warranted.