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Medline ® Abstract for Reference 36

of 'Treatment of relapsed or refractory acute lymphoblastic leukemia in adults'

Phase I clinical and pharmacology study of clofarabine in patients with solid and hematologic cancers.
Kantarjian HM, Gandhi V, Kozuch P, Faderl S, Giles F, Cortes J, O'Brien S, Ibrahim N, Khuri F, Du M, Rios MB, Jeha S, McLaughlin P, Plunkett W, Keating M
J Clin Oncol. 2003;21(6):1167.
PURPOSE: To define the maximum-tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of clofarabine, given as a 1-hour infusion daily for 5 days, in patients with solid tumors and with acute leukemia.
PATIENTS AND METHODS: The initial part of the study defined the MTD and DLT in solid tumors. The second part of the study defined the MTD and DLT in acute leukemia.
RESULTS: The starting dose of clofarabine (15 mg/m(2)) was myelosuppressive, requiring several dose de-escalations to 2 mg/m(2), the dose suggested for phase II studies in solid tumors. Dose escalation in acute leukemia started at 7.5 mg/m(2), with several escalations to 55 mg/m(2). The DLT was reversible hepatotoxicity at 55 mg/m(2). The recommended dose for acute leukemia phase II studies was 40 mg/m(2). Among 32 treated patients with acute leukemia, two achieved a complete response and three had a marrow complete response without platelet recovery (hematologic improvement), for an overall response rate of 16%. At 40 mg/m(2), the median plasma clofarabine level was 1.5 micro mol/L (range, 0.42 to 3.2 micro mol/L; n = 7). Cellular and plasma pharmacokinetic studies suggested dose proportionality but showed a wide variation in intracellular concentrations of clofarabine triphosphate.
CONCLUSION: This phase I study defined the following two MTDs for clofarabine given as a 1-hour infusion daily for 5 days: 2 mg/m(2) for solid tumors, the DLT being myelosuppression; and 40 mg/m(2) for acute leukemia, the DLT being hepatotoxicity. Encouraging activity was observed in acute leukemia.
Departments of Leukemia, Experimental Therapeutics, and Breast and Head and Neck, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA. hkantarj@mdanderson.org