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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Chemical research in toxicology 5 (1992), S. 95-99 
    ISSN: 1520-5010
    Source: ACS Legacy Archives
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cisplatin (CDDP), 5-fluorouracil (5-FU), and hydroxyurea (HU) have individually demonstrated activity against several solid tumors, act synergistically with each other in vitro, and may act as radiation sensitizers. Therefore, we designed a phase I study to determine the maximally tolerated dose of cisplatin as given in addition to our previously described combination of 5-FU, HU, and concomitant radiotherapy (XRT). Patients exhibiting advanced solid tumors requiring palliative XRT were eligible. The regimen consisted of 1 g HU given p.o.b.i.d. on days 1–5,600 mg/m2 5-FU given i.v. daily by continuous infusion (c.i.) on days 1–5, escalating doses of cisplatin starting at 10 mg/m2 daily given by c.i. on days 1–5, and involved-field XRT carried out on days 1–5. The cycle was repeated every 14 days until the target XRT dose had been reached. In all, 19 patients were entered at the first dose level, and cumulative grade 3–4 myelosuppression was seen in 16 subjects. As no dose escalation was feasible, the chemotherapy was subsequently altered by using the above regimen for cycles 1, 3, 5, and 7 and substituting the less myelosuppressive regimen of 1 g HU given p.o.b.i.d. on days 1–5, 400 mg/m2 5-FU given i.v. daily by c.i., and 100 mg leucovorin given p.o. 4 h on days 1–5 for cycles 2, 4, and 6. On this alternating program, 28 patients were treated with escalating doses of CDDP. The dose-limiting toxicity was again myelosuppression, which was prohibitive at a CDDP dose of 20 mg/m2 daily. In the final phase of the protocol, 30 subjects were treated with the above alternating-cycle regimen at a CDDP dose of 20 mg/m2 daily and a decreased HU dose of 500 mg p.o.b.i.d. in an attempt to circumvent the myelosuppression associated with this dose of CDDP. Although severe acute toxicity (cycles 1 and 2) was observed less frequently, cumulative toxicity (all cycles) remained pronounced. The other major toxicity encountered was mucositis, which was particularly pronounced in patients receiving radiation to the head and neck and following leucovorin-containing cycles. Plasma concentrations of free platinum did not correlate with the CDDP dose, possibly due to the narrow range of doses given. Pharmacodynamic modeling demonstrated that the CDDP dose and the HU dose were associated with leukopenia. Antitumor activity was demonstrated in a number of solid tumors, particularly non-small-cell lung cancer and head and neck cancer. Due to the high incidence of severe cumulative toxicity, we recommend further use of this regimen only as part of a curative treatment strategy for patients presenting with locoregionally advanced solid tumors.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A total of 21 patients with advanced cancer were entered into a phase I study to determine the maximum tolerable dose (MTD) of liposome-encapsulated doxorubicin (LED) given weekly for 3 consecutive weeks at doses of 20, 30, or 37.5 mg/m2 per week. For a comparison of the pharmacokinetic behavior of LED with that of standard-formulation doxorubicin, 13 patients received a dose of standard-formulation doxorubicin 2 weeks prior to the first dose of LED. All doses were given by 1-h infusion through a central vein. Toxicity was evaluated in 22 courses delivered to 17 patients. The MTD with this schedule was 30 mg/m2 per week×3. The single patient treated at 37.5 mg/m2 weekly could not complete the entire course due to myelosuppression. At the dose of 30 mg/m2 per week, three of eight patients had grade ≥3 leukopenia. Other toxicities included mild to moderate thrombocytopenia, nausea, vomiting, fever, alopecia, diarrhea, fatigue, stomatitis, and infection. At the dose of 30 mg/m2 per week, the total doxorubicin AUC and peak total doxorubicin concentrations in plasma were 8.75±8.80 μM h (mean±SD) and 3.07±1.45 μM, respectively, after LED administration. The total doxorubicin AUC and peak total doxorubicin concentrations in plasma were 3.92±2.47 μM h and 2.75±2.70 μM, respectively, after the infusion of standard-formulation doxorubicin. The total body clearance of doxorubicin was 18.42±11.23 l/h after the infusion of LED and 31.21±15.48 l/h after the infusion of standard-formulation doxorubicin. The mean elimination half-lives of doxorubicin were similar: 8.65±5.16 h for LED and 7.46±5.16 h for standard-formulation doxorubicin. Interpatient variability in pharmacokinetic parameters as demonstrated by the percentage of coefficients of variation was 33%–105%. There was no relationship between the percentage of WBC decrease or the duration of WBC suppression and the total doxorubicin or doxorubicinol AUC. There was no correlation between the duration of leukopenia and drug exposure as reflected by the AUC of liposome-associated doxorubicin. LED can be given in doses similar to those of standard-formulation doxorubicin and produces acute toxicities similar to those caused by standard doxorubicin.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0843
    Keywords: Key words: Paclitaxel – Taxol – Pharmacokinetics – Mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. We defined the pharmacokinetics of paclitaxel after i. v., i. p., p. o., and s. c. administration of 22.5 mg/kg to CD2F1 mice. Additional mice were studied after i. v. bolus dosing at 11.25 mg/kg or 3-h continuous i. v. infusions delivered at 43.24 μg kg–1 min–1. Plasma was sampled between 5 min and 40 h after dosing. Brains, hearts, lungs, livers, kidneys, skeletal muscles, and, where applicable, testicles were sampled after i. v. dosing at 22.5 mg/kg. Liquid-liquid extraction followed by isocratic high-performance liquid chromatography (HPLC) with UV detection was used to determine paclitaxel concentrations in plasma and tissues. After i. v. administration to male mice, paclitaxel clearance (CLtb) was 3.25 ml min–1 kg–1 and the terminal half-life (t 1/2) was 69 min. After i. v. administration to female mice, paclitaxel CLtb was 4.54 ml min–1 kg–1 and the terminal t 1/2 was 43 min. The bioavailability of paclitaxel was ~10%, 0, and 0 after i. p., p. o., and s. c. administration, respectively. Paclitaxel bioavailability after i. p. administration was the same when the drug was delivered in a small volume to mimic the delivery method used to evaluate in vivo antitumor efficacy or when it was delivered in a large volume to simulate clinical protocols using i. p. regional therapy. Paclitaxel was not detected in the plasma of mice after i. p. delivery of the drug as a suspension in Klucel : Tween 80. Pharmacokinetic parameters were similar after i. v. delivery of paclitaxel at 22.5 and 11.25 mg/kg; however, the CLtb calculated in these studies was much lower than that associated with 3-h continuous i. v. infusions. After i. v. administration, paclitaxel was distributed extensively to all tissues but the brain and testicle. These data are useful in interpreting preclinical efficacy studies of paclitaxel and predicting human pharmacokinetics through scaling techniques.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0843
    Keywords: Key words DuP-941 ; Pharmacokinetics ; Limited-sampling strategy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The pharmacokinetics of a drug in individual patients can be estimated using plasma samples collected at a limited number of time points. However, different methods for a limited-sampling strategy (LSS) design exist and the optimal method has not yet been defined. Plasma concentration data were available from 27 of 74 courses in a phase I study (dose range, 5–55 mg m-2) of the novel anthrapyrazole DuP-941. Three approaches to LSS development were compared. Firstly, forward stepwise regression (FSR) was used to derive equations to predict the DuP-941 area under the concentration-time curve (AUC) based on plasma concentrations measured at specified times. LSSs were developed using 14 randomly chosen data sets and were validated using the remaining 13 data sets. Secondly, “all subsets” regression (ASR) was used to develop LSSs. A jack-knife technique was also used to allow model development utilising 26 data sets and validation on the 27th data set. Thirdly, an LSS was developed using optimal sampling theory (OST), and the LSS was used in conjuction with a Bayesian algorithm. Selected sampling times for four-point LSSs were 10, 65, 185 and 485 min (FSR) and 10, 45, 200 and 480 min (OST). Ten candidate LSSs were developed using the ASR approach. ASR- and OST/Bayesian-derived four-point LSSs gave more precise (P〈0.05) estimates of AUC [mean absolute percentage of difference (MAD%)  ± SD: ASR, 6.4±3.7%; OST/Bayesian, 6.8±4.6%] than did FSR (MAD%=15.1±9.9%). The OST/Bayesian approach is recommended because it allows estimation of all model parameters and is more flexible with regard to sample collection time and design variables.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0843
    Keywords: Key words BE-4-4-4-4 ; Polymines ; Pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The pharmacokinetics of 1, 19-bis(ethylamino)-5, 10, 15-triazanonadecane (BE-4-4-4-4) were determined in CD2F1 female mice after administration of i.v. bolus doses of 20 mg/kg (approximately the dose lethal to 10% of the study animals, ∼LD10) as well as 15, 10, and 5 mg/kg and after s.c., i.p., or p.o. doses of 20 mg/kg. BE-4-4-4-4 in plasma and urine was derivatized with dansyl chloride and measured by gradient high-performance liquid chromatography (HPLC) with fluorescence detection. Data were modeled by noncompartmental and compartmental methods. The declines observed in plasma BE-4-4-4-4 concentrations after i.v. delivery of 20, 15, 10, and 5 mg/kg were modeled simultaneously using an interval of 2000 min between doses and were best approximated by a two-compartment, open, linear model. The time courses of plasma BE-4-4-4-4 concentrations after i.p. and s.c. delivery were fit best by a two-compartment, open, linear model with first-order absorption. Peak plasma concentrations of BE-4-4-4-4 measured following an i.v. dose of 20 mg/kg ranged between 30 and 33 μg/ml, the terminal elimination half-life was 94 min, and the volume of distribution (Vdss) was 850 ml/kg. The plasma pharmacokinetics of BE-4-4-4-4 were linear with dose. BE-4-4-4-4 (0.5 and 2.0 μM) in mouse plasma was approximately 67% protein-bound. Bioavailabilities after i.p., s.c., and p.o. delivery were 40%, 50%, and approximately 3%, respectively. Urinary excretion of parent BE-4-4-4-4 in the first 24 h after dosing accounted for less than 30% of the delivered dose. As BE-4-4-4-4 proceeds toward and undergoes clinical evaluation, the data and analytical method presented herein should prove useful in formulating a dose-escalation strategy and, possibly, evaluating toxicities encountered.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cancer chemotherapy and pharmacology 42 (1998), S. S22 
    ISSN: 1432-0843
    Keywords: Key words Clinical pharmacology ; Anticancer agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The rationale for studying the clinical pharmacology of antineoplastic agents is that the information obtained will result in enhanced drug development and enhanced or improved clinical use. A great deal of effort has been expended in studying the pharmacokinetics and pharmacodynamics of investigational and noninvestigational antineoplastic agents. More recently, a deeper appreciation has developed regarding the importance of the metabolism of antineoplastic agents and the potential role of metabolites in their activity or toxicity, as well as the potential for drugdrug interactions. Investigators studying the clinical pharmacology of antineoplastic agents face an increasingly challenging task as new agents continue to be developed. Some of these challenges arise from the enhanced potency of new agents, resulting in increased difficulty in measuring such agents in biological matrices. Furthermore, as agents have been developed to affect specific biological targets, the necessity of assessing pharmacodynamics at the biochemical or molecular level has become increasingly important. In addition, development of agents with cytostatic, as opposed to cytotoxic, properties poses a further challenge to assessment of pharmacologic effect. In addressing these challenges, a great deal of effort has been expended to develop increasingly sensitive analytical chemical techniques, in evaluating alternative biological matrices, such as saliva, in which to monitor drug concentrations in a less invasive fashion, and in developing limited sampling strategies to assess both the pharmacokinetics and pharmacodynamics of antineoplastic agents. Similarly, a great deal of effort has been expended in providing suitable means for assessing the numerous novel targets for which antineoplastic agents are being developed. These include the assessment of cell cycle kinetics and specific oncoproteins, definition of cell damage such as cleavable complexes, and formation of drug-macromolecular adducts in suitable target cells. Additional effort is being expended to explore nontraditional means of drug delivery. In this regard, the increasing importance of orally administered agents reflects a fundamental change in the approach to antineoplastic drug delivery. Finally, the increased computational power made available by faster personal computers has facilitated a number of innovative modeling techniques involving population modeling, modeling of combination chemotherapy, and assessment of drug-drug interactions.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To determine whether dimethylsulfoxide (DMSO) can potentiate antitumor activity of cyclophosphamide (CYC) in patients with squanmous cell carcinoma of the lung, 14 patients were treated with 5 l of a 5% or 6% DMSO solution PO over 3 days and 1,500 mg CYC/m2 IV as a 60-min infusion on the third day of treatment. Serial blood, CSF, and urine samples were collected to assess the pharmacokinetics of CYC. Courses were repeated every 3–4 weeks. No antitumor responses were observed. Toxicity was mainly hematologic and similar to that of CYC alone. There was one death from infection during granulocytopenia. Nonhematologic toxicity was moderate to severe and included nausea (14 patients) and vomiting (five patients). The plasma pharmacokinetics of CYC in this study are similar to previously reported results for CYC alone, but the 24-h urinary excretion of CYC in our study is much lower than previously reported. Further studies in tumors more responsive to CYC may be warranted.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A phase II study of intermittent high-dose 6-thioguanine (6-TG) was undertaken in 19 patients with metastatic colorectal carcinoma. Fourteen patients had received prior myelosuppressive therapy. 6-TG was administered as a single dose by IV bolus over 15–30 min, with retreatment every 3 weeks. The starting dose was 700 mg/m2 in ten patients, 900 mg/m2 in one patient, 1,000 mg/m2 in four patients, and 1,200 mg/m2 in two patients. Two patients received reduced doses (350 mg/m2) because of liver dysfunction. There was no regression of measurable disease after treatment with 6-TG in this study. Eight patients achieved stabilization of previously progressive disease for periods of 10–32 weeks. Toxicities were nausea and vomiting (19 patients), mucositis (3 patients), reversible renal dysfunction with creatinine〉2 mg/dl (4 patients), nasal congestion (3 patients), diarrhea (1 patient), and skin blistering at the infusion site (1 patient). Seven patients had white blood count nadirs below 3,000/μl (the lowest nadir was 900/μl). Only one patient had a platelet count nadir below 100.000/μl. There were no infections or hemorrhage. 6-TG, as administered in this study, has no antitumor activity against colorectal carcinoma. Concentrations of 6-TG and metabolites were assessed in the plasma of six patients by a reversed-phase HPLC system. 6-TG and metabolites were extracted from human plasma at 50%–100% efficiency by cold 2 N perchloric acid (1 : 1). Neutralized extracts were chromatographed on a μ-Bondapak C18 column by two separate isocratic conditions. 6-TG, 6-thiouric acid, 6-thioguanosine, and 6-thioxanthine were analyzed with 0.01 M Na acetate, pH 3.5/10% methanol as the mobile phase and were detected at 340 nm. 6-Methyl TG and three unknown metabolites were eluted with Na acetate/25% methanol and were detected at 310 nm. External standard calibration was used for quantitation. The 6-TG detection limit was 0.8 nmol/ml. In six patients who received 1–1.2 g 6-TG/m2 IV, 6-TG achieved peak plasma concentrations of 61–118 nmol/ml (95.6 ± 23.0, mean ± SD). Plasma 6-TG concentrations decayed bi-exponentially, with initial t1/2 of 3 h and terminal t1/2 of 5.9 h. 6-Thiouric acid, 6-methyl TG, 6-thioguanosine, 6-thioxanthine, and three major unidenitified metabolites were also observed in plasma. The three unknowns were extracted with ethyl acetate from alkalinized pooled plasma extracts and were purified by HPLC.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Twenty-nine patients with non-small cell lung cancer refractory to prior therapy were treated with either vindesine (VDS) alone (3 mg/m2 every week) or the combination of VDS plus cisplatin (DDP) (100 mg/m2 every 28 days). Serial blood and urine samples were colletected to assess the pharmacokinetics of VDS and DDP. All patients were evaluable for toxicity and 27 were evaluable for response. No objective antitumor responses were observed. Peripheral neuropathy manifested by paresthesias, muscle weakness, and constipation were observed in 20 treated patients, and hematologic toxicity consisting of thrombocytopenia and/or leukopenia occurred in 18 patients. The plasma and urinary pharmacokinetics of VDS and DDP measured in this study indicate that VDS and DDP do not interfere with each other and that the pharmacokinetics in previously treated and untreated patients are similar. The antitumor responses and degree of toxicity observed in this trial compare unfavorably with previously reported VDS and VDS-DDP trials in previously untreated patients with this disease and suggest that prior exposure to chemotherapy might both decrease antitumor activity and enhance toxicity of these chemotherapeutic agents.
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