This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Egorin, M. J. Articles by Van Echo, D. A. Search for Related Content PubMed PubMed Citation Articles by Egorin, M. J. Articles by Van Echo, D. A.

A Limited Sampling Strategy for Cyclophosphamide Pharmacokinetics¹

Division of Developmental Therapeutics [M. J. E., A. F.] and Medical Oncology [C. P. B., J. S. A., D. A. V. E.], University of Maryland Cancer Center; Division of Medical Oncology, Department of Medicine, University of Maryland School of Medicine [M. J. E., C. P. B., M. J. R., J. S. A., D. A. V. E.]; and Department of Clinical Pharmacy, University of Maryland School of Pharmacy [A. F.], Baltimore, Maryland 21201; and Lynn Sage Clinical Pharmacology Laboratory for Cancer Research, Joint Section of Hematology/Oncology, Department of Medicine, University of Chicago Pritzker School of Medicine, and Michael Reese Hospital and Medical Center, Chicago, Illinois 60616 [M. J. R.]

A limited sampling strategy was developed to estimate the total area under the curve of plasma cyclophosphamide concentrations versus time (AUC). The strategy was developed with a training set consisting of 29 pharmacokinetic studies in 16 patients who received 1-h i.v. infusions of cyclophosphamide at a dosage of 1000 mg/m². The strategy was developed by applying stepwise forward multiple regression analysis to cyclophosphamide concentrations observed at each time in the training set (independent variables) versus the AUC (dependent variable). It was confirmed by applying stepwise backward elimination regression analysis to the same data set. The final sampling strategy, which utilized three time points, was: , where C₂₄, C₄, and C₁ represent plasma cyclophosphamide concentrations at 24, 4, and 1 h, respectively, and the dosage is in mg/m² (r = 0.98). The strategy was validated prospectively with a test data set consisting of 14 pharmacokinetic studies in 11 patients who received 1-h i.v. infusions of cyclophosphamide at dosages of 300, 600, or 1200 mg/m². The strategy proved highly predictive, with correlation coefficient between predicted and actual AUC of 0.94. The strategy also proved unbiased, with mean percentage of error (±SE) of 3.3 ± 3.6%, and precise, with mean absolute percentage of error of 9.3 ± 2.7%. The sampling strategy developed is being used in a multiinstitution trial of cyclophosphamide in an effort to relate cyclophosphamide pharmacokinetics, as expressed by AUC, with the toxic or therapeutic pharmacodynamic responses of the drug.

¹ Supported in part by Grants U10CA44691, U10CA31983, and Contract CM57734 awarded by the National Cancer Institute, NIH, Department of Health and Human Services, and by a Special Investigator Award to J. S. A. from the Maryland Division of the American Cancer Society.

² To whom requests for reprints should be addressed, at Division of Developmental Therapeutics, University of Maryland Cancer Center, 655 W. Baltimore St., Baltimore, MD 21201.

³ Recipient of a Clinical Oncology Career Development Award from the American Cancer Society.

Received 10/ 7/88. Accepted 3/ 7/89.

This article has been cited by other articles:

				C. E. B. Linares, D. Griebeler, D. Cargnelutti, S. H. Alves, V. M. Morsch, and M. R. C. Schetinger Catalase activity in Candida albicans exposed to antineoplastic drugs. J. Med. Microbiol., March 1, 2006; 55(Pt 3): 259 - 262. [Abstract] [Full Text] [PDF]

				R. J. Motzer, M. Mazumdar, J. Sheinfeld, D. F. Bajorin, H. A. Macapinlac, M. Bains, L. Reich, C. Flombaum, T. Mariani, W. P. Tong, et al. Sequential Dose-Intensive Paclitaxel, Ifosfamide, Carboplatin, and Etoposide Salvage Therapy for Germ Cell Tumor Patients J. Clin. Oncol., March 13, 2000; 18(6): 1173 - 1180. [Abstract] [Full Text] [PDF]

				Y. Y. Hon and W. E. Evans Making TDM work to optimize cancer chemotherapy: a multidisciplinary team approach Clin. Chem., February 1, 1998; 44(2): 388 - 400. [Abstract] [Full Text] [PDF]

				B. Kaplan, H.-U. Meier-Kriesche, K. Napoli, and B. D. Kahan A Limited Sampling Strategy for Estimating Sirolimus Area-Under-the-Concentration Curve Clin. Chem., March 1, 1997; 43(3): 539 - 540. [Full Text] [PDF]