Mitoxantrone in advanced breast cancer: a phase II trial of the Southwest Oncology Group

Second-line chemotherapy with mitoxantrone as a single agent in metastatic breast cancer

Ninety-three evaluable patients with metastatic breast cancer previously treated with chemotherapy, received mitoxantrone as a single agent (14 mg/m2, by rapid intravenous infusion, once every 3 weeks). Patients received a median of 7 courses (range 2 to 18), with a mean cumulative total dose of 133 mg (range 36 to 342). A complete response (CR) was achieved in 2 patients (2%). Partial response (PR) was observed in 23 patients (25%). The overall response rate (CR+PR) was thus 27%, with a median duration of 9 months (range 3 to 18). Responses were observed in all metastatic sites, except for brain and peritoneum. Stabilization (S) occurred in 26 patients (28%). The remaining 42 patients (45%) showed clear progression of their metastatic disease while on therapy. The actuarial 24-month survival for the whole group was 13%, increasing to 29% in responders (CR+PR), as compared with only 10% for non-responders (S+P; P < 0.0001). Mitoxantrone was generally well tolerated; nausea, vomiting and hair loss were mild. Nine out of 625 treatment cycles resulted in leukopenic fever with uneventful recovery. All patients had serial MUGA scans; 3 patients (cumulative total doses of 200, 250 and 342 mg, respectively) developed a significant drop in the left ventricular ejection fraction. Clinical evidence of congestive heart failure was observed in one patient who had received prior doxorubicin-based adjuvant chemotherapy. Mitoxantrone seems to be as effective as other drugs given singly or in combination as second-line chemotherapy in patients with metastatic breast cancer. Its low morbidity makes its use attractive in this setting.

Early assessment of a new anticancer drug analogue--are the historical comparisons obsolete? The French experience with pirarubicin

Data of all phase II studies of pirarubicin (THP-doxorubicin) have been analysed for toxicity or activity in breast cancer and compared with published reports on doxorubicin, epirubicin or mitoxantrone used as single drugs. A graph of the 95% confidence intervals for each event was used. The results suggest that pirarubicin is as effective as other intercalating drugs in breast cancer and grossly better tolerated than doxorubicin, especially alopecia and cumulative cardiotoxicity. The equimyelotoxic doses of each drug were also estimated. The methodology and the validity of such historical comparisons is discussed: they cannot replace prospective randomised phase III studies, and do not allow definitive conclusions. However, most comparative trials of anticancer drug analogues cannot answer the right questions because their objectives are not adequate (especially for equiefficacy). But early evaluation by historical comparisons can help the conception of phase III studies.

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.

Effectiveness of mitoxantrone on the proliferation of cell cultures derived from malignant mesenchymal tumors of human origin

The antiproliferative potency of mitoxantrone (MITOX) has predominantly been established for epithelial and hematologic neoplasias. In this study the effectiveness of MITOX was investigated in vitro for 6 sarcomatous human cell lines derived from 2 synovial sarcomas, a malignant schwannoma, a malignant histiocytoma, a leiomyosarcoma, and a chondrosarcoma. The examination was performed using a proliferation assay with monolayer cell cultures. The effect of MITOX was compared with that of adriamycin (ADR) and cisplatin (CDDP). For each drug at least 3 concentrations were tested which covered the therapeutically achievable range, i.e., for MITOX 0.2-0.002 micrograms/ml, for ADR 0.5-0.005 micrograms/ml, and for CDDP 5.0-0.05 micrograms/ml. Test incubations were performed for 3 days. Antiproliferative potency of the cytostatic drugs was assessed by counting the number of cells at the start and the end of the test period with and without drug addition. Furthermore the dose inhibiting cell growth to 50% of controls (ID50) was determined for MITOX. For comparison 4 cell lines from carcinomatous lesions were included in the study. MITOX inhibited proliferation rates of 4 sarcomatous tumor cell lines more intensively than ADR, and was less effective in 2 cell lines. However, these differences were not significant. In all mesenchymal cell lines tested the antiproliferative potency of MITOX was more pronounced than that of CDDP. In carcinomatous cell lines the MITOX-induced growth inhibition was similar to that found in response to administration of ADR and CDDP confirming the described effect on epithelial tumors. The study suggests that MITOX possesses a growth inhibitory potency for malignant soft tissue tumors in vitro. From these data it may be worthwhile to initiate clinical trials testing the treatment of sarcomatous lesions with MITOX.

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.

Suppression of experimental allergic encephalomyelitis by mitoxantrone

Treatment of rats with a developing or an established lesion of experimental allergic encephalomyelitis (EAE) with mitoxantrone (Novantrone) suppressed the hind limb paralysis associated with the disease. Histopathological examination of the spinal cords of these rats showed that mitoxantrone-treated rats had reduced vascular lesions that are associated with EAE. Spleen cells derived from immunized rats that had been treated in vivo with mitoxantrone did not transfer disease when these cells were administered to naive syngenic recipients. In addition, spleen cells from diseased rats did not transfer EAE lesions when these cells were administered to recipients that had been treated with mitoxantrone. Recipients treated with mitoxantrone were resistant to EAE lesions induced by sensitized cells in a rapid passive transfer system. Finally, when spleen cells from rats with EAE were incubated, in vitro, with mitoxantrone, these cells did not transfer disease to recipients. Thus the present studies indicate that treatment with mitoxantrone can suppress the lesions associated with both the active and passive forms of EAE.