Mitoxantrone treatment in advanced breast cancer

A randomised trial of second-line hormone vs single agent chemotherapy in tamoxifen resistant advanced breast cancer

Sixty patients with advanced breast cancer unresponsive to tamoxifen have been randomised to receive four course of mitozantrone, 14 mg m-2 (n = 30) intravenously every 3 weeks (9 weeks total) or megesterol acetate, 160 mg bd (n = 30). One in three patients (11 from each group) had substantial disease control for a minimum period of 6 months i.e., lack of progression; seven patients (23%) showed objective response to mitozantrone compared to four (13%) receiving megesterol. Non-progressive disease occurred in all sites, including visceral metastases and receptor negative patients. There were no significant differences between treatment groups in the median time (5 months each) to disease progression response duration or survival (13 months megesterol, 11 months mitozantrone) from commencing second-line therapy. Toxicity was considerably higher in the mitozantrone group. Second-line hormonal therapies can produce similar therapeutic results as those achieved from a short course of a 'short option' single agent cytotoxic in patients who were previously thought hormone insensitive. Provided that the patient does not have life threatening disease a trial of megesterol acetate is worth consideration in that it does not prejudice subsequent response to combination cytotoxic chemotherapy.

Mitoxantrone. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in the chemotherapy of cancer

Mitoxantrone is a dihydroxyanthracenedione derivative which as intravenous mono- and combination therapy has demonstrated therapeutic efficacy similar to that of standard induction and salvage treatment regimens in advanced breast cancer, non-Hodgkin's lymphoma, acute nonlymphoblastic leukaemia and chronic myelogenous leukaemia in blast crisis; it appears to be an effective alternative to the anthracycline component of standard treatment regimens in these indications. Mitoxantrone is also effective as a component of predominantly palliative treatment regimens for hepatic and advanced ovarian carcinoma. Limited studies suggest useful therapeutic activity in multiple myeloma and acute lymphoblastic leukaemia. Regional therapy of malignant effusions, hepatic and ovarian carcinomas has also been very effective, with a reduction in systemic adverse effects. Mitoxantrone inhibits DNA synthesis by intercalating DNA, inducing DNA strand breaks, and causing DNA aggregation and compaction, and delays cell cycle progression, particularly in late S phase. In vitro antitumour activity is concentration- and exposure time-proportional, and synergy with other antineoplastic drugs has been demonstrated in murine tumour models. Leucopenia may be dose-limiting in patients with solid tumours, whereas stomatitis may be dose-limiting in patients with leukaemia. Other adverse effects are usually of mild or moderate severity although cardiac effects, particularly congestive heart failure, may be of concern, especially in patients with a history of anthracycline therapy, mediastinal irradiation or cardiovascular disease. Mitoxantrone displays an improved tolerability profile compared with doxorubicin and other anthracyclines, although myelosuppression may occur more frequently. Thus, mitoxantrone is an effective and better tolerated alternative to the anthracyclines in most haematological malignancies, in breast cancer and in advanced hepatic or ovarian carcinoma. Further studies may consolidate its role in the treatment of these and other malignancies.

Phase I and II agents in cancer therapy: I. Anthracyclines and related compounds

Anthracycline antibiotics remain among the most potent anticancer drugs, but their efficacy is limited by the development of a dose-dependent irreversible cardiomyopathy and by the emergence of clones of tumor cells resistant to the effects of the drug. Modifications of the basic anthracycline structure have resulted in molecules that may share the activity of the parent compound, with amelioration of some toxicities, absence of cross-resistance, or activity against tumors insensitive to the parent drug. Epirubicin has a unique metabolic pathway, glucuronidation, that may result in more rapid plasma clearance and reduced toxicity as compared with doxorubicin. Epirubicin has demonstrated comparable activity to doxorubicin in breast cancer, with possibly reduced toxicity. Idarubicin is of interest because of its cytotoxic activity when given orally. Idarubicin has prolonged retention in the plasma and has equal cytotoxic activity to the parent compound. Idarubicin has demonstrated activity against acute leukemia and breast cancer; in the latter tumor category, some doxorubicin-resistant tumors have responded. Esorubicin is of interest because of its nearly absent cardiac toxicity. This agent has some activity against solid tumors and is currently being clinically tested. Aclacinomycin A is an anthracycline in which a trisaccharide is substituted for the aminosugar. Aclacinomycin A and the related compound marcellomycin are of interest as both cytotoxic and differentiating agents. Menogaril is an anthracycline with the aminosugar on the D ring; it does not exhibit cross-resistance with doxorubicin or cardiotoxicity. Mitoxantrone is a compound that is related to the anthracyclines but has a different mechanism of action. This agent has significant activity against acute leukemia and breast cancer and is currently being compared with doxorubicin. Amsacrine is another compound related to the anthracyclines that possesses major activity against acute leukemias. Minor modifications of the anthracycline molecule have had major impact on the biologic activity of these drugs. New anthracycline analogues with up to 100 times the potency of currently available anthracyclines are being developed for clinical testing, and these complex molecules retain a nearly unlimited potential for structural modification.