Human pharmacokinetics of WR-2721

The pharmacokinetic properties of WR-2721 were investigated in 13 cancer patients given a 150 mg/M2 intravenous bolus dose of the drug. An average plasma clearance value of 2.17 L/min was obtained. Very little of the drug or the two metabolites, WR-1065 and WR-33278, were excreted in urine obtained after the blood collection schedule. Plasma concentrations of WR-2721 decreased by 94% within 6 minutes of drug administration. The mean value of 6.44 L obtained for the steady-state volume of distribution indicates that the extravascular space occupied by the drug is small. These observations suggest that in human cancer patients, WR-2721 is rapidly taken up by tissues and converted to metabolites.     

Clinical phase I trial of marcellomycin with a single-dose schedule

Marcellomycin is a new anthracycline that was proposed for clinical trials on the basis of experimental data suggesting reduced potential for hematologic and cardiac toxicity as compared to conventional anthracyclines. This phase I trial was designed to determine the maximum tolerated dose of marcellomycin at a single-dose schedule. The drug was given as a 15- to 30-min i.v. injection. Eighteen patients with a variety of solid tumors received a median of 2 courses (range: 1–5) at doses of 5–60 mg/m². Myelosuppression was dose-limiting and somewhat unpredictable. It was characterized by early thrombocytopenia and late leukopenia. It occurred at doses ⩾40 mg/m² and resulted in a few cases of infection and hemorrhage. Nausea, vomiting and stomatitis were frequent and occasionally severe. Other common non-hematological toxic effects consisted of local phlebitis and fatigue. Electrocardiographic changes were also encountered. Hair loss was rare and negligible. No antitumor activity could be detected. It appears that phase II trials should be preferably restricted to ambulatory patients and that a dose schedule of 50 mg/m² repeated every 3 weeks may be proposed for this favorable patient population.     

A phase I trial of marcellomycin with a weekly dose schedule

Marcellomycin, a new anthracycline antibiotic, was administered intravenously on a weekly schedule to 22 patients with advanced malignant solid tumors. Patients were treated at 6 dosage levels ranging from 5 to 30 mg/m² weekly for 4 weeks. Courses were repeated after a 3-week rest period. Hematologic toxicity was dose-limiting but unpredictable. Of 10 patients treated with weekly doses of 27.5 mg/m², 3 patients exhibited myelosuppression and 2 died in agranulocytosis. Moderate to severe nausea and vomiting occurred in 19 of 22 evaluable patients. Other toxic effects were non-acute and consisted of mild stomatitis, diarrhea, phlebitis and moderate fatigue in 1–3 patients each. In 17 patients evaluable for antitumor activity no partial or complete responses occurred. One patient with advanced breast cancer showed a mixed response. Marcellomycin given on a weekly dose schedule has unpredictable and erratic hematologic toxicity. The maximally tolerated dose appears to be between 27.5 and 30 mg/m² weekly. However, no firm recommendations can be given for a dose level that results in tolerable, predictable and reversible toxicity.     

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.     

乳腺癌患者化疗中应用磷酸肌酸对心肌的保护作用

目的观察磷酸肌酸治疗乳腺癌采用蒽环类化疗药物引起心肌损害的疗效。方法207例患者随机分为对照组和观察组,观察组112例,对照组95例。两组均给与心内科常规药物,观察组给予磷酸肌酸钠1g／d静脉推注。观察治疗前后患者心肌酶谱、C反应蛋白和心电图改变情况。结果两组治疗后心肌酶水平均下降,观察组下降较对照组明显（P〈0．05）。两组治疗后c反应蛋白水平均下降,观察组下降较对照组明显（P〈0．05）,治疗后观察组c反应蛋白明显较对照组低（P〈0．05）。两组患者经过化疗共有123名患者出现心电图改变,治疗后两组心电图改变均有改善,治疗组改善较明显（P〈0．05）。结论磷酸肌酸可应用于乳腺癌化疗患者,对于预防和治疗葸环类化疗药物心脏毒性有一定作用。     

Human plasma pharmacokinetics of thiotepa following administration of high-dose thiotepa and cyclophosphamide

Thiotepa is an established alkylating agent whose pharmacokinetics in standard doses are well defined. In order to ascertain whether dose-dependent variations in pharmacokinetics occur, we have undertaken an analysis of plasma thiotepa levels in 16 patients entered on a phase I-II study of bialkylator chemotherapy. High-dose thiotepa (1.8 to 7.0 mg/kg) and cyclophosphamide (2.5 g/m2) were administered intravenously (IV) on days -6, -4, and -2 followed by autologous marrow reinfusion on day 0. Plasma and urinary thiotepa was assayed by gas chromatography. Biexponential plasma decay curves were seen in ten patients, with a t 1/2 alpha of 10.0 +/- 6.4 minutes, a t 1/2 beta of 174 +/- 61 minutes and a total body clearance of 379 +/- 153 mL/h/kg (mean +/- SD). Six patients displayed monoexponential plasma decay curves with a terminal t 1/2 of 137 +/- 83 minutes and a total body clearance of 440 +/- 195 mL/h/kg. Although there was a trend toward reduced plasma clearance in the three patients treated at the highest dose level, the available data suggest that metabolic clearance mechanisms for thiotepa were not saturated with the doses used in this study. By stepwise regression analysis, linear functions using only 15-minute and four-hour postinfusion plasma levels were derived that correlated closely with area under the plasma concentration X time curves (AUC) (P less than .002). We conclude that high-dose thiotepa results in similar pharmacokinetic values to conventional doses with no apparent dose-dependent variation. The value of specific time points to predict AUC and clearance will require prospective evaluation.     

Induction of erythroid differentiation by the anthracycline antitumor antibiotics, aclacinomycin A, musettamycin and marcellomycin

The oligosaccharide anthracycline aclacinomycin A is of considerable clinical interest since, in comparison to adriamycin and daunomycin, the compound exhibits reduced cardiac toxicity and is devoid of mutagenicity/carcinogenicity. In addition, induction of differentiation in the human promyelocytic leukemia cell line HL 60 and possibly in one case of human acute myeloblastic leukemia by aclacinomycin A has been observed. Our data indicate that aclacinomycin A and related compounds, such as musettamycin and marcellomycin, are extremely potent inducers of differentiation in mouse (Friend leukemia cells, clone F4-6), rat (rat erythroleukemia, clone D5A1), and human erythroid cell lines (K 562 cell line) and that the relative inductive potency of marcellomycin and musettamycin, in general, is higher than that of aclacinomycin A. This potency difference may be due to the presence of a Cl-hydroxyl group in the aglycone of the marcellomycin and musettamycin molecule. Thus, oligosaccharide anthracyclines are a new class of inducers of erythroid differentiation. The high potency of these compounds, the possibility to study structure-activity relationships relative to their inductive potency and the fact that they induce erythroid differentiation in cells of different species as well as granulocytic differentiation in human cells should facilitate the study of basic mechanisms of hemopoietic differentiation. In addition, the therapeutical significance of these anthracycline effects should be investigated by studying, comparatively, the differentiation-inducing and antitumor effects of these compounds in primary leukemic cell cultures from patients.     

Inhibition of glycoprotein biosynthesis by the inducers of HL-60 cell differentiation, aclacinomycin A and marcellomycin

The trisaccharide-containing anthracyclines aclacinomycin A (ACM) and marcellomycin (MCM) have been shown by our laboratory to be potent inducers of HL-60 leukemia cell maturation, while the monosaccharide-containing anthracyclines Adriamycin and pyrromycin were inactive and significantly less potent, respectively, as initiators of the differentiation of these malignant cells. We have now observed that ACM and MCM are potent inhibitors of both total glycoprotein synthesis and the formation of lipid-linked oligosaccharide intermediates in intact HL-60 cells. This inhibitory activity was both concentration and time dependent and was maximal after 12 hr exposure to 30 nM ACM or MCM, conditions under which both cell growth and total protein synthesis were maintained at levels equal to those of untreated cells. In contrast, exposure of HL-60 cells to pyrromycin or Adriamycin, even at cytotoxic concentrations, did not result in specific decreases in the synthesis of glycoproteins containing asparagine-linked oligosaccharides. Maximum inhibition of the formation of lipid-linked intermediates by ACM or MCM preceded the loss of cell surface transferrin-binding activity (maximal at 24 hr), which in turn preceded the minimal exposure time necessary for significant induction of differentiation by either of the active anthracyclines (36 hr). These findings demonstrate a new biochemical site of action for ACM and MCM and suggest that this activity is involved in the induction of terminal differentiation of HL-60 leukemia cells by these antitumor agents.     

Human IgM monoclonal antibody 16.88: pharmacokinetics and immunogenicity in colorectal cancer patients.

Twenty colorectal cancer patients were given an intravenous injection of human IgM monoclonal antibody (MAb) 16.88 (8 mg) conjugated to 131I for tumor localization. After a 2-week interval, a second injection with 200, 500, or 1000 mg of unlabeled antibody added was given to groups of five patients each. at the end of the 2-hour infusion, 66% of the radioactivity remained in the circulation. Blood clearance of the 131I-labeled MAb 16.88 was biphasic with a mean half-life (T1/2 alpha) of 12 hours and T1/2 beta of 45 hours. Clearance rate was 0.09 L/hour. More than 90% of the 131I in serum was protein bound, with an immunoreactive fraction of 80% in the first 48 hours. Size exclusion chromatography indicated no degradation products other than 131I in serum and urine. The urinary excretion rate of 131I increased to 1.5% of the dose per hour at 24 hours, with 50% of the dose excreted in 34 hours. The pharmacokinetic profile of 131I-labeled MAb 16.88 was neither influenced by the total protein dose of antibody administered nor affected by specific uptake in tumor tissue in individual patients, as determined on early immunoscintigrams. The larger antibody doses showed a slightly slower excretion of 131I. The assays applied to determine immunogenicity were enzyme-linked immunosorbent assay, radioimmunoassay, and the dot-blot assay. They had sensitivities ranging from 5 ng/mL to 0.5 micrograms/mL for goat or rabbit antihuman IgM. The assays did not reveal antihuman antibody responses.     

Human tumor fluorouracil trapping: clinical correlations of in vivo 19F nuclear magnetic resonance spectroscopy pharmacokinetics

We previously reported that fluorouracil (5FU) accumulation and metabolism in human livers and tumors can be studied by in vivo nuclear magnetic resonance spectroscopy (NMRS). We have extended these observations by evaluating the pharmacokinetics of 5FU in the tumors of 11 patients with carcinoma of the breast, colon, endometrium, cervix, and kidney, using 19F-NMRS in a 1.5 Magnetom (Siemens Medical Systems, Cerrito, CA) magnetic resonance imaging unit (MRI). These NMRS measurements detected a long-lived tumor pool of 5FU in six of 11 tumors in our patients including carcinomas in the pelvis, breast, lung, and liver. The half-life (T1/2) of this tumor pool of "trapped" 5FU was 0.33 to 1.3 hours (20 to 78 minutes), much longer than the T1/2 of 5FU in blood (5 to 15 minutes). Neither the anabolites of 5FU (fluorinated nucleosides, nucleotides, 5FU-RNA, or 5FU-thymidylate synthase) nor the catabolites (eg, fluorobetaalanine [FBAL]) were detectable by 19F NMRS. Patient response to chemotherapy appeared to correlate with the extent of trapping of free 5FU in the human tumors: in the seven patients receiving 5FU, or 5FU or FUdR plus leucovorin, four of four patients whose tumors trapped 5FU responded to fluorinated pyrimidine chemotherapy, whereas three patients in whom there was a failure to detect tumor trapping were resistant to 5FU. We conclude that NMRS is clinically feasible, and enables investigators to study 5FU pharmacokinetics and metabolism in tumors in vivo. 19F-NMRS of 5FU allows for in vivo evaluation of 5FU metabolic modulation and might be able to guide therapeutic decisions.     

Comparative ultrastructural studies of nucleoli of tumor cells treated with adriamycin and the newer anthracyclines, carminomycin and marcellomycin.

This study was designed to determine the effects of several antitimor anthracyclines, including Adriamycin and its analogs, carminomycin and marcellomycin, on the ultrastructure of nucleoli of Novikoff hepatoma cells. Adriamycin and carminomycin, which are structurally related, induce nucleolar segregation following the formation of conspicuous fibrillar centers. Marcellomycin did not induce formation of nucleolar fibrillar centers. Instead, numerous microspherules formed following treatment with marcellomycin; later complete nucleolar segregation developed. The microspherules were observed to be in various stages of extrusion from the nucleolar body. This microspherule "migration" appeared to be both time and drug concentration dependent. These results show that the rate and extent of nucleolar ultrastructural aberration may be related to structural differences of the various anthracyclines.     

Animal pharmacokinetics in the quantitative estimation of clinical pharmacokinetics of antitumor agents

Animal extrapolation of antitumor drug pharmacokinetics deals with either the determination of equations describing drug disposition or the determination of physiological parameters governing this distribution. Papers on this subjects show the need for numerous animal species to predict quantitative evolution curves and the lack of precision in the obtained results. Practical interest of such studies is limited since the pharmacokinetic parameters are systematically evaluated in man during phase I trials. On the contrary, analysis of the mechanism of drug distribution cannot be performed without interspecies scaling to evaluate physiological parameters which are not measurable in humans.     

Circadian pharmacokinetics of methotrexate

Summary Six patients with intermediate- and high-grade non-Hodgkin's lymphoma were treated with 400 mg/m² i.v. methotrexate (MTX) at 0600 and 1800 hours. Despite evidence of circadian rhythms in renal function, the pharmacokinetics of total and free serum MTX showed no significant difference between these two times. The marked two-fold circadian variation in MTX pharmacokinetics previously reported in rats was not observed in these patients.     

Population pharmacokinetics of oxaliplatin

The objective of this study was to explore correlations between a variety of covariates and oxaliplatin ultrafilterable and blood pharmacokinetic parameters. Data from 40 patients receiving oxaliplatin combined with 5-fluorouracil and levofolinic acid as standard treatment for advanced colorectal cancer were analysed. Plasma ultrafilterable, blood, and urine platinum concentrations were determined by flameless atomic absorption spectrophotometry. Data were analysed according to a population pharmacokinetic method using the NONMEM program. The best fit for oxaliplatin plasma ultrafilterable clearance (CL) was given by the following equation, which considers four covariates: body surface area (BSA, in metres squared), age (in years), sex (0 if male, 1 if female), and serum creatinine (Scr, in micromoles per liter): CL (l/h)=5.49xBSA+4.55xBSAx(140-AGE)x(1-0.15xSEX)/Scr. By taking into account these covariates, the interindividual variability in CL decreased from 43% to 33%. Renal clearance represented 34% of the overall elimination. This value was obtained by recovering urine over only 5 h from the beginning of the infusion and modelling the data using NONMEM. We would recommend the use of this methodology for pharmacokinetic studies in oncology in which renal clearances of the drug are presently rarely explored. The oxaliplatin blood concentrations versus time observed during the three-cycle period were well-described by a three-compartment model with first-order elimination from the central compartment. No significant intrapatient pharmacokinetic variability was observed between cycles. The relationship we obtained using the population approach between oxaliplatin CL and covariates may allow rational reduction of oxaliplatin dose in cases of elevated serum creatinine levels.     

Preclinical pharmacokinetics of benznidazole

Benznidazole is a lipophilic analogue of misonidazole (MISO) which shows promise as a chemosensitizer for clinical use, particularly in combination with CCNU. We have investigated the detailed pharmacokinetics of benznidazole in mice, dogs and sheep to provide a data base for the estimation of doses required for chemosensitization in man. Pharmacokinetic behaviour was linear except at high doses in mice. Absorption was fairly rapid and bioavailability was complete following both i.p. administration in mice and oral administration in dogs. Elimination t1/2 values were longer than for MISO, being 90 min in mice, 4-5 h in sheep and 9-11 h in dogs. At doses giving linear kinetics, peak whole plasma concentrations per administered mg kg-1 were 0.75 micrograms ml-1 for the i.p. route in mice and 1.8 micrograms ml-1 for the oral route in dogs. Though between 39 and 59% of plasma benznidazole was bound to protein, tissue penetration was generally good. Tissue/whole plasma ratios ranged from 59-99% for transplantable mouse tumours and from 14-70% for spontaneous dog neoplasms. Nervous tissue penetration was similar to that in tumours: brain/whole plasma ratios averaged between 61 and 76% in mice and 42% in dogs, while peripheral nerve/whole plasma ratios in dogs averaged 74%. Mean liver/whole plasma ratios were 42% and 71% in BALB/c and C3H/He mouse strains respectively. Only approximately 5% of the administered dose was excreted unchanged in the urine, indicating the likelihood of extensive metabolism. These data show that benznidazole should have suitable pharmacokinetic properties for clinical use as a chemosensitizer. Enhancement of CCNU response is likely to require circulating benznidazole concentrations of 10-30 micrograms ml-1 and we predict that these will be obtained with oral doses of 6-20 mg kg-1 in man.     

Clinical pharmacokinetics of nitrosoureas

The pharmacokinetic characteristics of chloroethylnitrosourea anti-cancer agents are based on their high chemical reactivity and subsequent rapid breakdown in the plasma; and on a widespread tissue distribution due to the molecules' lipophilic properties. These physico-chemical properties explain the main problems that one may face during pharmacokinetic studies (assay method, isolation of high reactive intermediates) and that are related to the typical pharmacokinetic profile of these agents: rapid gastro-intestinal absorption, short half-life, widespread pulmonary and renal distribution, passage through the blood-brain barrier with levels within a therapeutic range, lipoprotein fixation, mainly hepatic and pulmonary metabolism, renal excretion. A drug interaction with phenobarbital has been described in the rat. The rational use of these compounds in cancer chemotherapy requires the optimisation of assay methods and a better understanding of their transformation pathways as well as their mechanism of action.     

Clinical pharmacokinetics of vindesine

Summary The pharmacokinetics of vindesine were investigated in five patients with advanced cancer who were receiving the drug. Following a rapid IV bolus dose, vindesine kinetics were described by a triphasic serum decay curve compatible with a three-compartment open mammillary model. Serum half-lives were 2 min, 50 min, and 24 h for the fast, middle, and slow phases, respectively. The volume of the central compartment approximated the plasma volume in all patients studied. Distribution occurred quickly into a superficial tissue compartment in fairly rapid equilibrium with the plasma compartment, and also into a deep tissue compartment with slower redistribution to the central compartment. The large apparent volume of distribution and long elimination half-live suggest extensive tissue sequestration or delayed excretion of the drug in man. The slightly increased serum half-life of vindesine compared with published results for vinblastine may account for the greater degree and longer duration of marrow suppression seen clinically with vindesine.     

Human plasma carboxylesterase and butyrylcholinesterase enzyme activity: correlations with SN-38 pharmacokinetics during a prolonged infusion of irinotecan

PURPOSE: To characterize the relationships between human plasma irinotecan carboxylesterase-converting enzyme activity, caboxylesterase-mediated hydrolysis of p-nitrophenyl acetate (pNPA), and the butyrylcholinesterase-mediated hydrolysis of butyrylthiocholine in human plasma and to test the ability of these in vitro tests to predict the variability in SN-38 pharmacokinetics in adult patients during a prolonged infusion of irinotecan. METHODS: Individual plasma-converting enzyme activity was measured in 20 adult cancer patients participating in a pharmacokinetic and phase I clinical trial of a prolonged 96-h intravenous infusion of irinotecan. The pNPA and butyrylthiocholine hydrolysis in patient plasma was also assayed. RESULTS: The irinotecan carboxylesterase-converting enzyme in human plasma had a Vmax of 89.9 +/- 22.7 pmol/h per ml plasma and a Km of 207 +/- 56 microM (mean +/- SD, n = 3). The mean value of the specific activity of this enzyme in 20 adult cancer patients was 10.08 +/- 2.96 pmol/h per ml plasma ranging from 5.43 to 15.39 pmol/h per ml. The area-under-the-concentration-versus time curve (AUC) ratio of SN-38 to irinotecan (AUCSN-38/AUCCPT-11) was used to assess the relative SN-38 exposure to the active metabolite in individual patients. Pharmacokinetic variations in the relative exposure to SN-38 did not correlate with the measured carboxylesterase-converting enzyme activity nor with plasma butyrylcholinesterase activity in our patient population. However, it did correlate with the measured pNPA hydrolysis activity in patient plasma (r2 = 0.350, P = 0.0124, n = 18). CONCLUSIONS: Determination of patient plasma pNPA hydrolysis activity may have utility in predicting SN-38 pharmacokinetics during prolonged infusions of irinotecan.     

Human alpha-lymphoblastoid interferon. A phase I study including pharmacokinetics and effects on hematologic stem cells (CFU-GMs)

Human alpha lymphoblastoid interferon (Wellferon) was administered to 33 patients in a phase I study. Patients received Wellferon intramuscularly every 12 hours for 14 doses in nine dosage levels ranging from 0.75 X 10(6) units to 50.0 X 10(6) units. Toxicity tended to be dose dependent and included fever/chills, malaise, hematologic toxicity, and digestive tract toxicity. Thirty X 10(6) u q 12 h was felt to be the maximum tolerated dose. Three partial responses (renal cell carcinoma, diffuse histiocytic lymphoma, Hodgkin's disease) were achieved. Interferon rapidly (2 to 3 hours after the initial injection) reached peak serum levels which varied generally with dose and exceeded 500 u/ml at the 30 and 50 X 10(6) u dosages. Multiple doses of interferon resulted in cumulative peak levels substantially higher than first dose levels (greater than 500 u/ml at dosages greater than 3 X 10(6) u/ml and greater than 1,500 u/ml at dosages greater than or equal to 18 X 10(6) u). Interferon given at high dosages persisted up to 10 days beyond the final injection. Despite hematologic toxicity, inhibition of CFU-GM was not seen.