The EORTC Early Clinical Trials Cooperative Group experience with 5-aza-2'-deoxycytidine (NSC 127716) in patients with colo-rectal, head and neck, renal carcinomas and malignant melanomas

The Early Clinical Trials Cooperative Group of the EORTC conducted several phase II studies with a pyrimidine analogue of deoxycytidine, 5-aza-2'-deoxycytidine (DAC). The drug was given as three consecutive 1 h i.v. infusions of 75 mg/m2, separated by intervals of 7 h; courses were repeated every 5 weeks. A total of 101 eligible patients were studied: 42 with colo-rectal adenocarcinoma, 27 with squamous cell carcinoma of the head and neck, 18 with malignant melanoma and 14 with renal cell carcinoma. Drug-induced toxicities consisted of moderate myelosuppression, and nausea and vomiting. One single partial remission was seen in a patient with malignant melanoma. DAC given in this dose and schedule is devoid of antitumour activity in adult patients with these refractory types of carcinomas.

Combination chemotherapy with methotrexate, bleomycin, and vincristine with or without cisplatin in advanced squamous cell carcinoma of the head and neck

A total of 185 eligible patients with advanced inoperable squamous cell carcinoma of the head and neck were randomized into two groups; the cisplatin, methotrexate, bleomycin, and vincristine (CABO) group received cisplatin (50 mg/m2; day 4), methotrexate (40 mg/m2; days 1, 15), bleomycin (10 mg; days 1, 8, and 15), and vincristine (2 mg; days 1, 8, and 15) and the ABO group received methotrexate, bleomycin and vincristine in the same doses on days 1, 8, and 15. After three courses, patients in both arms received weekly methotrexate as maintenance therapy; those 34 patients with previously untreated locoregional disease went off the study because of subsequent locoregional treatment in form of radiotherapy +/- surgery. The complete response rate was 16% in patients receiving CABO, compared with 5% among patients given ABO. The corresponding overall response rates were 50% and 28%, respectively (P = 0.003). Among patients with recurrent or metastatic disease, progression was delayed in patients receiving CABO (median, 18 weeks) compared to those receiving ABO (median, 14 weeks) (P = 0.07), but there was no difference in survival time. Myelosuppression consisted mostly of leukopenia, which was seen in 67% of the CABO patients versus 47% in the other arm. Myelosuppression-associated infection and hemorrhage led to death in two patients in the CABO treatment group and six patients in the ABO treatment group. Nausea and vomiting, mostly of grades 1 or 2, occurred in 93% of the patients given CABO and 44% of those receiving ABO. Other toxic effects--neuropathy, alopecia, stomatitis, constipation, fever/chills, diarrhea, cutaneous alterations, and renal impairment--occurred equally in the two treatment groups. This study underlines the role of cisplatin in head and neck cancer, although no impact on survival could be demonstrated. It also supports indirectly the superiority of combination chemotherapy over single-agent treatment for this disease.

Phase II trial of anaxirone (1,2,4-triglycidylurazol, TGU) in patients with advanced ovarian carcinoma: an EORTC Gynecological Cancer Cooperative Group Study

Sixteen patients with advanced ovarian carcinoma were treated with anaxirone (1,2,4-triglycidylurazol, TGU), 600 mg/m2 every 4 weeks. Anaxirone was the second or later line of therapy. All patients had evaluable tumors and evidence of failure of prior therapy. None of the patients responded. Two had stabilization of the disease for 4 months. In one patient WHO grade 4 leukopenia and grade 4 thrombocytopenia were observed after the second TGU cycle starting on day 41 and persisted until the patient died due to tumor progression (day 50). No patient experienced thrombophlebitis.

Loss of fluorescence by anthracycline antibiotics: effects of xanthine oxidase and identification of the nonfluorescent metabolites

Rat liver cytosol and buttermilk xanthine oxidase both converted 7-deoxypyrromycinone, the 7-deoxyaglycone of marcellomycin, a new anthracycline antibiotic, to a nonfluorescent compound under anaerobic conditions and in the presence of an electron donor. Reduced nicotinamide adenine dinucleotide and reduced nicotinamide adenine dinucleotide phosphate were equally effective electron donors for liver cytosol, and xanthine was the best cofactor for xanthine oxidase. However, xanthine was inactive with liver cytosol. Reactions with xanthine oxidase obeyed Menten-Michaelis kinetics and were inhibited by allopurinol. No xanthine oxidase activity was detected in liver cytosol. Xanthine oxidase also induced a loss of fluorescence when incubated with 7-deoxydaunorubicin aglycone. The nonfluorescent metabolite of 7-deoxypyrromycinone was tentatively identified as the dihydroquinonic derivative of the parent deoxyaglycone on the basis of its spectrophotometric, fluorescent, thin layer chromatographic, and mass spectral characteristics. Our data demonstrate that more than one enzymatic activity, xanthine oxidase, and an unidentified rat liver cytosolic enzyme convert the 7-deoxyaglycones of anthracycline antibiotics to nonfluorescent metabolites.

Comparison of pharmacokinetics and bactericidal activity of teicoplanin and vancomycin

Teicoplanin (0.2 g) or vancomycin (1 g) were infused over 3 and 50 min respectively to six male volunteers in a cross-over study. Each drug was administered twice at a 14 h interval. The pharmacokinetics of both drugs were accurately described using a two-compartment model. Vancomycin had a shorter half-life (5.8 +/- 1.8 h) compared to teicoplainin (33.2 +/- 5.1 h; P less than 0.001). One hour serum was tested for serum bactericidal activity against ten strains each of Staphylococcus aureus (median serum bactericidal activity 1:16 for teicoplanin; 1:32 for vancomycin), Staph. epidermidis (1:32 for teicoplanin and for vancomycin) and Streptococcus faecalis (1:2 for both drugs). Serum killing rate studies showed a slower rate of killing of Staph. aureus with teicoplanin (less than 1 log10 cfu/ml over 6 h) than with vancomycin (4 log10 cfu/ml over 6 h).

Comparative anthracycline metabolism in rats: loss of marcellomycin fluorescence

The in vitro metabolism of marcellomycin by rat tissue fractions showed conversion of marcellomycin to 7-deoxypyrromycinone, bisanhydropyrromycinone, and an as yet unidentified compound by rat liver homogenate, microsomes, cytosol, and mitochondria, and purified hepatic reduced nicotinamide adenine dinucleotide phosphate-cytochrome P-450 reductase, under anaerobic conditions and in the presence of reduced nicotinamide adenine dinucleotide phosphate. All these fractions except the purified reductase subsequently induced a progressive loss of fluorescence. Mitochondria, however, were much less active than microsomes, cytosol, and homogenate in inducing this latter phenomenon. Marcellomycin was converted to 7-deoxyaglycones only partially by nuclei. No loss of fluorescence was observed with this subcellular fraction. No loss of fluorescence was observed when doxorubicin or daunorubicin were incubated under similar conditions. The appearance of a compound with distinct spectrophotometric properties was demonstrated by absorbance spectrometry. The formation of a compound with different fluorescent characteristics was excluded, as was the binding of the aglycones to subcellular components. The activity inducing the loss of fluorescence was studied in greater detail with cytosol. It predominated in the liver and required both an electron donor and anaerobic conditions. The optimal pH for the reaction was between 7.5 and 8.0. Our results suggest the existence of an enzymatic pathway capable of converting the fluorescent nucleus of marcellomycin to a nonfluorescent metabolite.

Primary resistance of renal adenocarcinoma to 1,2,4-triglycidylurazol (TGU, NSC 332488), a new triexpoxide cytostatic agent--a phase II study of the EORTC early clinical trials group

Fourteen patients with metastatic renal adenocarcinoma without prior chemotherapy were treated with 1,2,4-triglycidylurazol (TGU, NSC-332488), a new triepoxide alkylating agent. TGU was chosen for this study among other triepoxides because of its high antitumour activity in animal models, its relatively good water solubility and the expected favourable therapeutic index. The starting dose was 800 mg/m2 i.v. (600 mg/m2 for patients with prior extensive radiotherapy) every 4 weeks. No objective tumour regression was seen in this favourable group of patients. Leuko- and thrombocytopenia were the most important side-effects. Severe cumulative and prolonged thrombocytopenia was seen. Other toxicities observed were nausea with or without vomiting in all patients and local phlebitis in some.

Phase I study of triglycidylurazol given on a 5-day i.v. schedule

Triglycidylurazol is a teroxirone derivative proposed for clinical trials on the basis of a broad spectrum of activity against murine tumors and a reduced potential for toxic manifestations at the injection site as compared to the parent compound. This phase I trial was designed to define the maximum tolerated dose of triglycidylurazol given by iv bolus on a 5-day schedule. Twenty-eight adult patients with a variety of solid tumors were entered. Their median performance status was 2 (range, 0-3), and most had received prior radiotherapy, chemotherapy, or both. A median of one course (range, one to four) was administered, for a total of 47 courses. Doses were escalated from 6 to 250 mg/m2/day. Leukopenia and thrombocytopenia were dose-related and -limiting, with a strong suggestion of increased myelosuppression with repeated courses. Nonhematologic toxic effects were generally mild to moderate. Nausea and vomiting were experienced by most patients. Local toxic effects consisting of venous discoloration, phlebitis, and/or sloughing were encountered in about one-half of the patients. Possible drug-related impairments in liver function were noted in three patients. Negligible alopecia and fatigue were also observed. Antitumor effect was detected in one patient with adenocarcinoma of unknown origin. A dose of 200 mg/m2/day for 5 consecutive days may be recommended for phase II trials.

Effect of hyperthermia on the in vitro metabolism of doxorubicin

The effect of hyperthermia on the uptake and metabolism of doxorubicin (ADM) was studied in in vitro systems. ADM uptake in rat liver slices was not affected by increasing the temperature from 37 degrees C to 43 degrees C. In rat liver homogenates, the aerobic transformation of ADM was low and was not affected by hyperthermia. Approximately 90% of the parent drug remained unchanged after 60 minutes of incubation, and two metabolites, adriamycinol and a polar metabolite, were formed in small amounts. Under anaerobic conditions, ADM was quickly and extensively converted to two metabolites identified as 7-deoxyadriamycinol aglycone and 7-deoxyadriamycin aglycone. Whereas the disappearance of ADM and the formation of 7-deoxyadriamycin aglycone were not modified by the hyperthermic conditions, there was a slight but significant increase of the formation of 7-deoxyadriamycinol alycone (area under the concentration versus time curve in microM X minute: 216 +/- 24 at 37 degrees C; 235 +/- 24 at 39.5 degrees C; and 271 +/- 8 at 42 degrees C; P less than or equal to 0.05). However, the percentage of dA3 was not significantly different at the end of the incubation.

Phase I study of intravenous menogaril administered intermittently

Thirty-three adult patients with solid tumors were treated with menogaril, a new anthracycline antibiotic. The drug was given as a two-hour infusion every 4 to 5 weeks at doses ranging from 17 to 250 mg/m2. The maximum tolerated dose was 250 mg/m2. Reversible and dose-related leukopenia was the dose-limiting toxicity. Thrombocytopenia was less frequent. Hematologic toxicity was maximal 2 weeks after treatment, and recovery usually occurred within 4 weeks. There was no dissociation between WBC and neutrophil counts, and myelosuppression did not appear to be cumulative up to 200 mg/m2. Myelosuppression was more severe for patients with heavy pretreatment and/or bone marrow involvement. Local toxicity consisting of phlebitis and/or erythema was the most common nonhematologic toxicity, especially at 250 mg/m2 (eight out of nine patients). Usually, erythema appeared within 24 hours after treatment at or near the infusion site and resolved within a few days. Occasionally, a more persistent (several weeks) orange discoloration suggesting cutaneous deposits of menogaril was observed. Nausea and vomiting were uncommon and never severe. Alopecia and mucositis were rare. Minor arrhythmias were seen in several patients during treatment, but their relationship with menogaril therapy was unclear, and in no patient did heart failure develop. Plasma concentrations were best described by a tricompartmental model with a mean terminal half-life of 29.5 hours and a mean total-body clearance of 20.2 L/h/m2. Doses of 160 and 200 mg/m2 are recommended for phase II trials in poor- and good-risk patients, respectively.

Interactions between cyclophosphamide and doxorubicin metabolism in rats. II. Effect of cyclophosphamide on the aldoketoreductase system

Under anaerobic conditions, in comparison to liver microsomes obtained from normal controls, liver microsomes obtained from rats pretreated with cyclophosphamide formed significantly less 7-deoxydoxorubicinol aglycone (P less than or equal to .05), whereas the disappearance of doxorubicin and the formation of 7-deoxydoxorubicin aglycone were unaffected. When directly investigated, the reduction of 7-deoxydoxorubicin aglycone to 7-deoxydoxorubicinol aglycone by microsomes was inhibited by cyclophosphamide pretreatment. Liver cytosols from controls and cyclophosphamide-treated rats reduced daunorubicin to daunorubicinol and 7-deoxydoxorubicin aglycone to 7-deoxydoxorubicinol aglycone at the same rate, which indicates the lack of effect of cyclophosphamide pretreatment on the cytosolic aldoketoreductase. The results suggest the existence of a microsomal carbonyl reduction system for anthracycline antibiotics and indicate that cyclophosphamide does affect the metabolism of doxorubicin; in rats, this interaction results only in an alteration of the relative concentrations of presumably inactive metabolites, the 7-deoxyaglycones. The importance of these findings for the pharmacological interaction between doxorubicin and cyclophosphamide in humans remains to be investigated.

Phase II study of a combination of hydroxyurea, fluorouracil and mitomycin in previously treated squamous cell carcinoma of the head and neck

Thirty-six evaluable patients with locoregionally recurrent or metastatic squamous cell carcinoma of the head and neck were treated with a combination of mitomycin (10 mg/m2 i.v. day 1), fluorouracil (500 mg/m2 i.v. days 1 + 8) and hydroxyurea (1 g/m2 orally days 2-14). Thirty-three patients had received prior radiation therapy and 34 prior chemotherapy. Only two patients exhibited a partial response. Hematological toxicity was substantial, with three patients experiencing leukopenia below 1000/mm3 and seven patients experiencing thrombocytopenia below 25,000/mm3. There were four cases of treatment-related bleeding and one infection. Other side-effects were mild to moderate. Low antitumor activity and substantial toxicity preclude further evaluation of this regimen in head and neck cancer.

In vitro activity of menogaril and N-demethylmenogaril in a human tumor cloning assay

The activity of menogaril and its major metabolite in animals and humans, N-demethylmenogaril, has been investigated in the human stem cell assay as developed by Salmon et al. Among 31 evaluable samples, four were sensitive to menogaril, including one which responded to N-demethylmenogaril. Three samples resistant to menogaril responded to N-demethylmenogaril. None was sensitive to doxorubicin. Overall, one out of seven ovarian samples and one out of three breast samples responded to menogaril. Our data confirm the in vitro activity of menogaril in ovarian and breast cancer; in addition, they suggest incomplete cross-resistance between doxorubicin and menogaril and, considering the concentrations of N-demethylmenogaril in animals and humans, a minor role for this metabolite in the overall antitumor activity of the parent compound.

Quantitation of differential sensitivity of normal marrow myeloid progenitor cells to anthracene derivatives

The effect of 3 anthracene derivatives, mitoxantrone, ametantrone, bisantrene, on 4 normal human bone marrows, was studied using the myeloid stem cell assay developed by Pike and Robinson, in order to define to what extent this test could be used to predict the relative clinical hematologic toxicity of new anticancer agents. For the 3 drugs, an exponential relationship between colony survival and drug concentration was found, but was much steeper for mitoxantrone (slope = -195.2 +/- 8.8/micrograms/ml) than for ametantrone (slope = 5.1 +/- 1.0/micrograms/ml, p less than or equal to 0.001) and bisantrene (slope = 7.1 +/- 0.3/micrograms/ml, p less than or equal to 0.001). The difference of slope between ametantrone and bisantrene was of borderline significance (p less than or equal to 0.05). The ratios of concentrations inducing a 50% growth inhibition for mitoxantrone versus bisantrene and for ametantrone versus bisantrene were close to the corresponding ratios of concentrations inducing a 90% growth inhibition. The relative in vitro toxicities reproduce very well the relative myelosuppression observed in clinical trials with mitoxantrone versus bisantrene but the results were less satisfactory for the comparison of these 2 agents with ametantrone. In addition, our data suggest that, for these 3 compounds, intrinsic myeloid progenitor sensitivity is a major determinant of leukopenia.

Phase I study of oral idarubicin given with a weekly schedule

Thirty one patients with solid tumors were entered into a phase I trial with idarubicin, a new anthracycline antibiotic with oral antitumor activity in animals. The drug was scheduled to be given for 4 consecutive weeks at doses ranging from 10 to 20 mg/m2. Leukopenia was the dose-limiting toxicity. Thrombocytopenia was occasionally seen. Since several patients could not receive the third and fourth administrations of the drug at 17.5 and 20 mg/m2, higher doses were administered only for 2 consecutive weeks. With this schedule, the maximum tolerated dose was 25 mg/m2 and leukopenia was again the dose-limiting toxicity. With both schedules, myelosuppression was highly variable and could not be related to prior therapy, bone or liver metastases, or performance status. Other toxicities were mild to moderate and were dominated by nausea and vomiting which were observed in 29% of the patients. Alopecia and mucositis were unfrequent and cardiac toxicity was not observed. Starting doses of 15 mg/m2 for 4 consecutive weeks or 20 mg/m2 for 2 consecutive weeks could be proposed for oral phase II studies with idarubicin, under careful pharmacokinetic monitoring.

Doxorubicin and cisplatin excretion into human milk

Plasma and milk concentrations of doxorubicin (DOX) and cisplatin were measured after iv administration of these agents to a lactating patient with ovarian cancer. Cisplatin was undetectable in human milk. Milk concentrations of DOX often exceeded those detected in concomitant plasma samples. For DOX, the highest milk:plasma concentration ratio was 4.43:1 and was observed 24 hours after administration of the drug. The area under concentration versus time curve (AUC) for DOX was approximately the same in plasma and milk. Doxorubicinol was the major metabolite of DOX in plasma and in milk. The AUC for doxorubicinol was ten times higher in milk than in plasma. However, the total amount of anthracycline antibiotic delivered in the milk (maximum concentration of active anthracycline antibiotic: 0.24 mg/L) was negligible.

Metabolism and disposition of menogaril (NSC 269148) in the rabbit

We have investigated the metabolism and disposition, in rabbits, of menogaril (7-OMEN), a new anthracycline antibiotic recently introduced into clinical trials. 7-OMEN was administered by rapid i.v. injection at a dosage of 2.5 mg/kg. 7-OMEN and metabolites were assayed by high performance liquid chromatography. Plasma concentrations of 7-OMEN declined in biexponential fashion with a terminal half-life of 2.7 h. The area under the plasma concentration versus time curve was 1.3 microM X h. The systemic clearance of 7-OMEN was 57.6 ml/min/kg. No metabolite of 7-OMEN was detected in plasma. At 8 h after treatment, the cumulative urinary and biliary excretions of 7-OMEN equivalents amounted to 1.3 and 3.4% of the total administered dose, respectively. 7-OMEN was the predominant fluorescent compound in urine, but four metabolites were also seen. In bile, 7-OMEN represented only 9.6% of the cumulative excretion and six metabolites were observed. Among the organs, lungs contained the highest concentrations of parent drug. Substantial concentrations of metabolites were observed in the kidneys, liver, duodenum, and small intestine. Three of the observed metabolites of 7-OMEN have been tentatively identified as N-demethylmenogaril, 7-deoxynogarol, and N-demethyl-7-deoxynogarol.

Comparative murine metabolism and disposition of class II anthracycline antibiotics

The metabolism and tissue distribution of aclacinomycin A (ACL), marcellomycin (MCM), and musettamycin (MST), three new anthracycline antibiotics, were compared after IV administration to mice. In plasma, total MCM- and ACL-derived fluorescence declined according to first-order kinetics, whereas an initial decline followed by a rebound was observed for MST. In plasma, MCM remained the predominant compound. ACL was eliminated more quickly, and was replaced by two metabolites, the reduced glycoside M1, and an aglycone. In the case of MST, two unidentified metabolites were observed in concentrations equivalent to that of the parent drug. The three drugs were distributed widely to organs, but only ACL achieved measurable concentrations in the brain. Initially, high concentrations of all three drugs were present in the lungs, but these decreased quickly to values similar to those present in the liver and kidneys. Intermediate concentrations of the three drugs were measured in heart and skeletal muscle. Splenic concentrations of all three drugs rose progressively, reaching a maximum at 8 h after injection in the case of ACL and MST, and at 24 h after injection in the case of MCM. Concentrations of the metabolites of MCM and MST were low in all organs except liver and kidney, where the aglycones 7-deoxypyrromycinone and bisanhydropyrromycinone were seen. The metabolism of ACL was extensive. Aglycones were dominant in the liver and kidneys, whereas reduced glycosides predominated in the spleen. These observations indicate that the murine pharmacology of these three structurally similar drugs differs markedly.

Human pharmacokinetics of esorubicin (4'-deoxydoxorubicin)

The pharmacokinetics of esorubicin, a new anthracycline antibiotic, was investigated in conjunction with a phase I clinical trial. The drug was administered to 12 patients as an intravenous bolus at a dose of 20 to 40 mg/m2. All patients had normal renal and hepatic functions and no third space fluid accumulation. Plasma and urine samples were assayed by HPLC. The peak plasma concentration of esorubicin was 0.74 +/- 0.57 microM (mean +/- SE). Esorubicin disappeared from plasma according to a tri-exponential pattern with a terminal half-life of 20.4 +/- 7.3 hr. The area under the plasma concentration versus time curve was 0.64 +/- 0.31 microM x hr. Total body plasma clearance was 45.5 +/- 26.8 liter/min/m2 and the apparent volume of the central compartment, 41.0 +/- 24.8 L. A single metabolite, 4'-deoxydoxorubicinol, was detected in plasma. This metabolite was observed in 5 patients only and its mean peak concentration was 0.029 +/- 0.017 microM. The area under the plasma versus concentration time curve for 4'-deoxydoxorubicinol was 0.02 +/- 0.014 microM xhr. The urinary excretion of total fluorescence within 5 days of therapy was 7.3 +/- 1.3% of the administered dose. Esorubicin represented more than 80% of the excreted anthracyclines. As in plasma, 4'-deoxydoxorubicinol was the only metabolite detectable in urine. No correlation between the various pharmacokinetic parameters and drug-induced toxicity was observed in this small group of patients.

Human pharmacokinetics of marcellomycin

In conjunction with two phase I clinical trials, we have investigated the pharmacokinetics of marcellomycin (MCM), a new class II anthracycline antibiotic, in nine patients with normal renal and hepatic functions and no third-space fluid accumulation. MCM was infused IV over 15 min at a dosage of 27.5, 40, or 50 mg/m2. Plasma and urine samples were collected up to 72 h. MCM and metabolites were assayed by thin-layer chromatography and quantified by specific fluorescence. The disappearance of total MCM-derived fluorescence from plasma followed first-order kinetics and lacked the rebound in total fluorescence that has been described for the structurally similar agent, aclacinomycin A. After 40-50 mg/m2, the peak MCM concentration in plasma was 1.67 +/- 0.61 microM; MCM disappeared from plasma in a triexponential fashion and was undetectable by 48 h after infusion. The area under the plasma concentration-time plot (AUC), including the infusion time, was 1.11 +/- 0.39 microM X h; plasma clearance of MCM was 1.50 +/- 0.88 l/min/m2. Five other fluorescent compounds were consistently observed in plasma. M2 was a contaminant present in the parent drug. P1 and P2 were conjugates of MCM and M2, respectively. G1 and G2 were aglycones. The peak concentrations of the metabolites were 25% or less or the peak concentration for MCM, but their persistence resulted in higher AUCs than that for MCM. For the dosage of 27.5 mg/m2, fewer data were available; but the pharmacokinetics of MCM and metabolites appeared to be similar to that at higher dosage. Urinary excretion of total fluorescence amounted to 8.0% +/- 1.6% of the total dose at 40-50 mg/m2, and to 7.0% +/- 2.3% at 27.5 mg/m2. No correlation was detected among the various pharmacokinetic parameters and toxicities encountered in these patients.

Combination chemotherapy with cisplatin, methotrexate, bleomycin, and vincristine (CABO) in advanced squamous cell carcinoma of the head and neck

A combination of cisplatin, methotrexate, bleomycin, and vincristine (CABO) was assessed in advanced epidermoid head and neck cancer. Among 72 patients with recurrent or metastatic disease and measurable lesions, there were 9 complete and 27 partial responses for an overall response rate of 50%. These results were adversely affected by prior surgery plus prior radiotherapy. The median response duration was 28 weeks (16-100+) in complete responders and 16 weeks (6-84) in partial responders. CABO was also administered to 56 patients with measurable, previously untreated, locoregional disease. In these patients, complete and partial response rates were 18% and 46%, respectively. Toxic effects were generally mild to moderate. In spite of its encouraging therapeutic efficacy, CABO is unlikely to be clearly superior to single-agent chemotherapy, at least in recurrent or disseminated disease. Increased effectiveness of CABO given as initial treatment suggests that chemotherapy might play an effective adjuvant role in carefully selected patients.

The disposition of the new anthracycline antibiotic, menogarol, in mice

We have investigated the metabolism and disposition, in mice, of 7-con-O-methylnogarol ( menogarol ; 7-OMEN), a new anthracycline antibiotic entering clinical trials. 7-OMEN, dissolved in 0.01 M glucuronic acid, was administered iv to mice (10 mg/kg). At specified times after injection, groups of mice were killed and 7-OMEN and metabolites were assayed in plasma and organs by HPLC. Plasma concentrations of 7-OMEN declined in triexponential fashion. The terminal t1/2 was 10.6 hr; the AUC was 10.13 microM X hr; the apparent Vc was 0.4 liter/m2, and the systemic clearance was 91.2 ml/min/m2. One metabolite, with the same HPLC characteristics as N- demethylmenogarol , was seen in plasma during the first 30 min after injection. 7-OMEN was distributed extensively to all tissues except brain. Initially, pulmonary concentrations of 7-OMEN were 15 times higher than those in any other organ and 30 times higher than those in plasma. Concentrations of 7-OMEN were the most persistent in spleen, kidney, and pancreas, and the least persistent in heart and liver. The AUC for 7-OMEN in organs was the greatest in lungs (605 nmol/g X hr), spleen (522 nmol/g X hr), and pancreas (430 nmol/g X hr), and least in heart (33 nmol/g X hr) and liver (60 nmol/g X hr). Kidneys and skeletal muscles had intermediate AUC values. In liver, two metabolites, one of which had the HPLC characteristics of N- demethylmenogarol , were seen. In other organs, the same metabolites were seen later and in small quantities.

Interactions between cyclophosphamide and adriamycin metabolism in rats

Rat liver microsomes under anaerobic conditions metabolize adriamycin (ADM) to 7-deoxyadriamycinol aglycone and 7-deoxyadriamycin aglycone. The metabolism of ADM and the concentration of cytochrome P-450 were not affected by preincubation with 2.76 mM cyclophosphamide. After preincubation of microsomes with 0.2 mM 4-hydroperoxycyclophosphamide, a prodrug of 4-hydroxycyclophosphamide, there was complete denaturation of the cytochrome P-450, and 22.8% inhibition of NADPH-cytochrome P-450 reductase. Under these conditions, the degradation of ADM was delayed (area under the concentration vs. time curve in micromolar X minutes: 15.6 +/- 2.4 for the controls, and 59.8 +/- 7.3 in the presence of 4-hydroperoxycyclophosphamide, P less than or equal to .005), 7-deoxyadriamycin aglycone increased progressively to reach a plateau at 20 min instead of showing a peak at 2 min and the formation of 7-deoxyadriamycinol aglycone was reduced. Microsomes from animals pretreated with cyclophosphamide (180 mg/kg i.p. once 4 days before sacrifice) showed a 24.0% reduction of NADPH-cytochrome P-450 reductase activity (P less than or equal to .02). This was accompanied by a decreased formation of 7-deoxyadriamycinol aglycone during the first 20 min of incubation (area under the concentration vs. time curve in micromolar X minutes: 68.0 +/- 15.7 in the controls, and 25.6 +/- 3.1 in the treated animals, P less than or equal to .005), whereas the formation of 7-deoxyadriamycin animals, P less than or equal to .005), whereas the formation of 7-deoxyadriamycin aglycone was not affected. These data indicate an interaction between the metabolism of cyclophosphamide and ADM in rats.