A randomized trial comparing mitoxantrone with doxorubicin in patients with stage IV breast cancer

Mitoxantrone (Novantrone; dihydroxyanthracenedione) is an anthraquinone previously shown to be active in human breast cancer. It appears to have less toxicity than doxorubicin. Results of this phase II-III randomized cross-over trial to determine the relative efficacy and toxicity of mitoxantrone in comparison to doxorubicin, are presented. Patients with measurable, recurrent breast cancer with limited prior chemotherapy with or without radiotherapy for metastatic disease, and who had not been exposed to prior doxorubicin, were randomized to receive either mitoxantrone or doxorubicin every three weeks with cross-over on progression. Response rates, duration of remission, time to treatment failure, and drug toxicity, including cardiac toxicity evaluated with serial radionuclide angiocardiography, were evaluated. Differences in the response rates for the two groups were not statistically significant. Neither time to treatment failure nor duration of response are significantly different (p greater than 0.05). With respect to toxicity, mitoxantrone treated patients consistently exhibited a lower incidence and less severe drug toxicity as compared to their doxorubicin-treated counterparts. Cardiac toxicity was carefully monitored and thus four patients on doxorubicin have had drug related congestive heart failure, as compared to none on mitoxantrone. In summary, mitoxantrone appears to be as active as doxorubicin in patients with stage IV breast cancer previously treated with chemotherapy; however, mitoxantrone causes significantly less nausea, vomiting, stomatitis and alopecia at doses which induce equal or greater myelosuppression than doxorubicin, and appears to be less cardiotoxic.