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Menogaril is a new anthracycline analog of nogalamycin. When administered as a 72-hour continuous iv infusion the dose-limiting toxic effect of menogaril was venous irritation at dose levels that cause only mild leukopenia and minimal gastrointestinal toxicity. Pharmacokinetic studies showed that the rise in plasma concentration during infusion was first-order, with a half-life of 11.9 hours. Total-body clearance of menogaril was 204 ml/minute/m2. There were no detectable metabolites of menogaril in plasma. Urinary excretion of unchanged menogaril was 17.3% of the dose and N-demethylmenogaril was 0.5% over 72 hours. Since menogaril does not appear to be metabolized, a high degree of tissue binding is likely.

Menogaril, a semisynthetic derivative of nogalomycin, was brought to phase I clinical testing in patients with refractory solid tumors. Twenty-seven patients received 50 evaluable courses. Menogaril was given as a 1-2-hour iv infusion on 5 consecutive days, with courses repeated every 4 weeks, provided there was reversal of all drug-related toxic effects. The starting dose was 3.5 mg/m2/day X 5, with escalations in subsequent cohorts of patients to 56 mg/m2/day X 5. Neutropenia was dose dependent and dose limiting. At 56 mg/m2/day X 5, the median wbc count nadir was 1100/microliter, and two of four patients were hospitalized for fever and suspected bacteremia. At 50 mg/m2/day X 5, the wbc count nadir was 2300/microliter. Platelet toxicity was less severe. Nonhematologic toxicity consisted primarily of local urticaria and moderate to severe phlebitis at the infusion site, which were dose dependent and lasted up to 6 weeks. For phase II studies, the recommended dose of menogaril is 50 mg/m2/day for 5 consecutive days administered as a 2-hour intermittent infusion, repeated every 28 days.

The chemotherapeutic activity of analogs of the anthracycline antibiotic, nogalamycin, was investigated in the P388 and L1210 leukemias and the B16 melanoma in mice. Among the compounds tested, 7-con-O-methylnogarol was found to have superior activity. Depending on the route and schedule of administration, increases in lifespan (ILS) in excess of 100% were observed in all three tumor systems. Additional testing of 7-con-O-methylnogarol demonstrated significant activity in the murine colon 26 and colon 38 tumors and the CD8F1 mammary tumor. 7-Con-O-methylnogarol was not significantly effective against murine Lewis lung carcinoma, although ILSs of 38% and 29% were achieved in two experiments. Activity was observed against ip inoculated P388 leukemia after ip, sc, oral, and iv drug administration. 7-Con-O-methylnogarol was also highly active (ILS greater than or equal to 120%) after ip drug administration to mice with iv inoculated P388 leukemia. Significant ILS values resulted from a variety of schedules of administration against ip inoculated P388 leukemia and B16 melanoma. Experiments in which the time of single-dose administration was varied prior to the time of ip P388 leukemia inoculation showed that residual drug or bioactive drug-related materials remained in mice for 8 hours after 50 mg/kg administered ip and for 48 hours after 200 mg/kg administered sc.

The magnitudes of the therapeutic and toxic responses observed when 7-con-O-methylnogarol (7-OMEN) was administered orally to mice inoculated ip or iv with P388 of L1210 leukemia were essentially equivalent to those seen after ip administration of the drug, indicating a significant degree of gastrointestinal absorption.

Mice bearing the P388/S or P388/ADR (doxorubicin-resistant) leukemia were treated with menogaril or mitoxantrone. Both drugs were highly effective against P388/S but were ineffective against the doxorubicin-resistant subline, indicating cross-resistance. These observations may be of use in the design of clinical trials with these drugs.