A phase I study of idarubicin hydrochloride in patients with acute leukemia. The Idarubicin Study Group of Japan.
This phase I trial of idarubicin (IDA) was conducted in 32 patients with acute leukemia and chronic myelogenous leukemia (CML) in blastic crisis (CML/BC) who either had failed to achieve a complete remission (CR) after initial induction therapy or had relapsed after CR. IDA was administered at dosages ranging from an initial dose of 5 mg/m2/d for 3 days with an increment of 2.5 mg/m2/d to 15 mg/m2/d for 3 days. The dose-limiting toxicities (DLTs) were thought to be stomatitis and anorexia. The maximum tolerated dose (MTD) was determined to be 15 mg/m2/d for 3 days (45 mg/m2 per course). Bone marrow toxicity was significant when greater than 10 mg/m2/d of IDA was given. When IDA was administered at this dosage or higher, there were three CRs and four partial responses, with an overall response rate of 26.9% in 26 assessable patients. It is recommended that a phase II study be undertaken at an IDA dosage of 10 to 15 mg/m2/d for 3 consecutive days in the treatment of acute leukemia. Twenty-one of 32 patients were also studied for the pharmacokinetics of IDA. The terminal half-life (t1/2) values for IDA were 6.4 to 15.1 hours in plasma and 8.09 to 16.34 hours in blood cells. The t1/2 values for idarubicinol were much longer: 43.46 to 51.01 hours in plasma and 36.61 to 54.70 hours in blood cells. Concentrations of idarubicinol in plasma and blood cells exceeded those of IDA 2 to 4 hours after the start of treatment and remained elevated for a long time. The area under the curve (AUC) of idarubicinol in plasma was 5.16 to 8.36 times higher than that of IDA, and the AUC of idarubicinol in blood cells was 2.05 to 4.57 times higher than that of IDA. The AUCs of both IDA and idarubicinol increased dose-dependently over the dosage range of 5 to 15 mg/m2/d. When two-compartment multiple-dose models were used, plasma t1/2 alpha and t1/2 beta values of IDA were 0.25 +/- 0.13 and 9.4 +/- 3.4 hours, respectively. The steady-state volume of distribution (Vdss) was 934.9 +/- 370.7 L/m2, and the plasma clearance was 82.3 +/- 29.7 L/h/m2. The urinary excretion of IDA and its metabolite was low. The mean cumulative urinary recovery rates were 2.04% for IDA and 11.53% for idarubicinol up to 7 days.
Department of Internal Medicine, Miyazaki Prefectural Hospital, Japan.
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Tamura
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000903:Antibiotics, Antineoplastic / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D019540:Area Under Curve; D001855:Bone Marrow Diseases / Q000139:chemically induced; D004305:Dose-Response Relationship, Drug; D005260:Female; D006207:Half-Life; D006801:Humans; D015255:Idarubicin / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007564:Japan; D007938:Leukemia / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D015394:Molecular Structure
D000903:Antibiotics, Antineoplastic; D015255:Idarubicin