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  • 1
    ISSN: 1432-0843
    Keywords: Key words Vincristine ; Liposome ; Pharmacology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: To establish the pharmacodynamic relationships between drug biodistribution and drug toxicity/efficacy, a comprehensive preclinical evaluation of sphingomyelin/cholesterol (SM/chol) liposomal vincristine and unencapsulated vincristine in mice was undertaken. Methods: Pharmaceutically acceptable formulations of unencapsulated vincristine and liposomal vincristine at drug/lipid ratios of 0.05 or 0.10 (wt/wt) were evaluated for toxicity, antitumor activity and pharmacokinetics following intravenous administration. Results: Mice given liposomal vincristine at 2 mg/kg vincristine had concentrations of vincristine in blood and plasma at least two orders of magnitude greater then those achieved after an identical dose of unencapsulated drug. One day after administration of the liposomal vincristine, there were at least tenfold greater drug quantities, relative to unencapsulated vincristine, in the axillary lymph nodes, heart, inguinal lymph nodes, kidney, liver, skin, small intestines and spleen. Increased plasma and tissue exposure to vincristine as a result of encapsulation in SM/chol liposomes was not associated with increased drug toxicities. Treatment of the murine P388 ascitic tumor with a single intravenous dose of unencapsulated drug at 2, 3 and 4 mg/kg, initiated 1 day after tumor cell inoculation, resulted in a 33 to 38% increase in lifespan. In contrast, long-term survival rates of 50% or more were achieved in all groups treated with the SM/chol liposomal vincristine formulations at doses of 2, 3 and 4 mg/kg. At the 4 mg/kg dose, eight of ten and nine of ten animals survived past day 60 when treated with SM/chol liposomal vincristine prepared at the 0.05 and 0.1 drug/lipid ratios, respectively. Conclusions: Overall, increased and prolonged plasma concentrations of vincristine achieved by liposomal encapsulation were correlated with dramatically increased antitumor activity in comparison with the unencapsulated drug, but no correlations could be established between pharmacokinetic parameters and toxicity.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0843
    Keywords: Key words Metastatic breast cancer ; Vinorelbine ; Phase I/II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: The Breast Cancer Site Group of the National Cancer Institute of Canada – Clinical Trials Group (NCIC-CTG) undertook two parallel phase I studies to determine the maximum tolerated dose (MTD) and recommended phase II dose of vinorelbine in combination with doxorubicin and fluorouracil (with or without folinic acid) in metastatic breast cancer. Methods: Cohorts of five patients were to receive: (a) fluorouracil 500 mg/m2 and doxorubicin 50 mg/m2 on day 1 only and escalating doses of vinorelbine (15, 20, 25, 30 mg/m2) on days 1, 8 and 15 every 3 weeks (FAN regimen), or (b) fluorouracil 340 mg/m2 and folinic acid 200 mg/m2 on days 1, 2, 3, 4 and 5, doxorubicin 40 mg/m2 on day 1 only and escalating doses of vinorelbine (15, 20, 25, 30 mg/m2) on day 1 and again on day 5 every 4 weeks (SUPERFAN regimen). Eligibility included measurable or evaluable metastatic breast cancer and having received neither previous chemotherapy for metastatic disease nor anthracycline-containing adjuvant therapy. Results: Of 26 and 12 patients enrolled in the FAN and SUPERFAN regimens, 26 and 12 were evaluable for toxicity and 21 and 9 for response, respectively. Median ages were 60.3 years (41–71 years) and 64.2 years (51–73 years). Both regimens required amendment after the first cohort with an original day-15 vinorelbine dose omitted from the FAN regimen and more prolonged nadir granulocyte counts allowed. Myelosuppression was dose limiting. MTDs in the FAN and SUPERFAN regimens were vinorelbine 25 mg/m2 and 20 mg/m2. Other toxicities included mucositis, septicemia and febrile neutropenia. Peripheral neuropathy and constipation were mild. Of the 21 FAN patients evaluable for response, 3 (14%) had complete responses and 7 (33%) had partial responses, for an overall response rate of 48%; 9 (43%) had stable disease and 2 (9%) had progressive disease as their best response. Of the nine SUPERFAN patients evaluable for response, none had a complete response. There were two (22%) with partial responses, and six (67%) had stable disease and one (11%) had progressive disease as their best response. Conclusions: The SUPERFAN regimen was too toxic to pursue even at the lowest dose. The recommended phase II starting dose for the FAN regimen was vinorelbine 20 mg/m2. Although these were phase I studies response rates in evaluable patients were less than expected and toxicity did not allow the use of as much vinorelbine in the combinations as had been anticipated. The limited response data from our study would imply that combining vinorelbine with more toxic agents may not enhance response rates and may defeat the advantage of tolerability, especially in elderly patients.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0843
    Keywords: Key words Vincristine sulfate ; Liposome-encapsulated vincristine sulfate ; Clinical pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The pharmacokinetic behavior of vincristine sulfate (VINC) following administration of vincristine sulfate liposome injection (VSLI), 0.16 mg/ml, as an intravenous infusion over 60 min in 24 of 25 patients enrolled in a phase I clinical study of this drug is described. Plasma samples for determination of the pharmacokinetic behavior of VINC were collected during the infusion at 15, 30 and 60 min as well as at 2, 4, 8, 12, 48 and 72 h postinfusion. Total VINC concentration was determined using a validated high-performance liquid chromatographic (HPLC) assay. Patients receiving doses of 0.5 to 1.5 mg/m2 VSLI did not provide useful pharmacokinetic data at late time-points owing to the limit of quantitation of the HPLC assay (28.6 ng/ml). Sufficient concentration-time data were available for seven of the patients receiving doses of VSLI from 2.0 to 2.8 mg/m2 for compartmental modelling. A two-compartment open model (PCNONLIN Model 10) was the best fit for the observed VINC plasma data for these patients. The mean maximum observed concentration values were significantly greater for patients receiving VSLI at 2.8 mg/m2 (2260 ± 212 ng/ml, n = 2) than for those receiving 2.0 mg/m2 and 2.4 mg/m2 (891 ± 671 ng/ml, n = 6; 679 ± 634 ng/ml, n = 6, respectively). No significant differences were observed in maximum concentration values between patients at 2.0 mg/m2 and those at 2.4 mg/m2. A trend towards higher parametric AUC (0 to ∞) values with increasing dose (on a milligram per meter squared basis) was observed but statistical significance was not reached. Comparison of the pharmacokinetic behavior of VSLI observed in this study with nonencapsulated VINC demonstrated that (1) the variability observed for VSLI pharmacokinetic parameters was similar to nonencapsulated VINC, (2) although variability in absolute concentration was observed␣between patients, the behavior of VSLI in individual patients followed a two- rather than a three-compartment open model, and (3) VINC plasma concentrations were significantly greater following administration of VSLI than described for nonencapsulated VINC. Overall, the results for patients treated with VSLI from 2.0 to 2.8 mg/m2 suggest that this formulation protects VINC from the early phase of rapid elimination seen with nonencapsulated drug, resulting in significantly elevated VINC plasma concentrations over extended periods of time.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2161
    Keywords: Key words Bone scan ; Osteopoikilosis ; Metastases ; Breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The authors report a case of metastatic breast carcinoma that on investigation was shown to have a negative bone scan in spite of multiple densely sclerotic metastases on radiography and CT and a positive bone biopsy. The literature is reviewed with regard to the subject of negative bone scans in this situation.
    Type of Medium: Electronic Resource
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