Idarubicin alone or in combination with cytarabine and etoposide (3 + 3 + 5 protocol) in acute non-lymphoblastic leukaemia

Etoposide: current status and future perspectives in the management of malignant neoplasms

Etoposide has demonstrated highly significant clinical activity against a wide variety of neoplasms, including germ-cell malignancies, small-cell lung cancer, non-Hodgkin's lymphomas, leukemias, Kaposi's sarcoma, neuroblastoma, and soft-tissue sarcomas. It is also one of the important agents in the preparatory regimens given prior to bone marrow and peripheral stem-cell rescue. Despite its high degree of efficacy in a number of malignancies, the optimal dose, schedule, and dosing form remain to be defined. It is possible that continuous or prolonged inhibition of the substrate, i. e., topoisomerase II, may be the key factor for the cytotoxic effects of etoposide. Clinical studies have shown the activity of etoposide to be schedule-dependent, with prolonged dosing, best accomplished by the oral dosing form, offering a therapeutic advantage. This benefit awaits validation by prospective randomized studies, some of which are in progress. Recent clinical investigations have focused on the use of etoposide in combination with (a) cytokines to ameliorate myelosuppression, the dose-limiting toxicity of etoposide; (b) agents such as cyclosporin A and verapamil to alter the p-glycoprotein (mdr1) function; and (c) topoisomerase I inhibitors to modulate the substrate upon which it acts. There is continued interest in the development of etoposide to its maximal clinical dimensions and in the examination of alternative biochemical and mechanistic approaches to further our understanding of this highly active agent.

Etoposide in leukemia

Etoposide (VP16-213, NSC 141540) induces a complete response (CR) in 15% to 25% of previously treated patients with acute nonlymphocytic leukemia (ANLL) when used as a single agent. Etoposide has been used successfully in combination with cytarabine, daunorubicin, and amsacrine for salvage and consolidation therapies. Previously untreated ANLL patients 15 to 70 years of age were randomly assigned to cytarabine (100 mg/m2) on days 1 to 7 plus daunorubicin (50 mg/m2) on days 1 to 3 (7-3) or to the same drugs plus etoposide (75 mg/m2) on days 1 to 7 (7-3-7). Patients achieving a CR received two consolidation courses (5-2, attenuated 7-3 or 5-2-5). Among 264 eligible patients, there was a 56% CR rate with 7-3 therapy and a 59% CR rate with 7-3-7 therapy. Remission duration was significantly improved with 7-3-7 (median, 12 months with 7-3 and 18 months with 7-3-7; P = 0.01), but survival was not. Subset analysis in patients younger than 55 years of age revealed prolonged remission (median, 12 months with 7-3 and 27 months with 7-3-7; P = 0.01) and survival (median, 9 months with 7-3 and 17 months with 7-3-7; P = 0.04) with the 7-3-7 regimen. Hematologic toxicity was similar for both regimens during induction, but significantly more severe for 7-3-7 during consolidation therapy. Etoposide is active in ANLL and prolongs remission when used in induction therapy.

Idarubicin in combination with etoposide and cytarabine in adult untreated acute non lymphoblastic leukemia

Thirty-one unselected patients with untreated acute non lymphoblastic leukemia (ANLL) ranging in age from 15 to 76 years received two courses of a new high-dose induction regimen consisting of idarubicin, etoposide and cytarabine. Patients who entered complete remission (CR) were then allocated to post-remission intensification (PRI). Patients under 40 years of age with a HLA-compatible donor were given bone marrow transplantation (BMT); those without an HLA identical donor received either autologous BMT (ABMT) or no subsequent therapy. Twenty-five out of 31 patients (80.6%) achieved CR (93.3% in young and 68.7% in old patients) and 14 (56%) after the first cycle. Six patients (five out six greater than 40 years) died of cerebral hemorrhage and/or infection during the induction phase and four additional patients (three elderly) died on the PRI for the same cause without recurrent disease. Eleven out 25 patients are disease-free survivors 2-34 months (median 10 months) after achievement of CR. In conclusion, this intensive chemotherapy regimen is effective both in young and older patients but the post-remission intensification is too aggressive in elderly patients.

Pharmacokinetics of idarubicin (4-demethoxydaunorubicin; IMI-30; NSC 256439) following intravenous and oral administration in patients with advanced cancer

The plasma pharmacokinetics of idarubicin (4-demethoxydaunorubicin) were studied in 20 patients with advanced malignant disease after intravenous (21 occasions) and oral (14 occasions) administration. Idarubicin plasma concentrations were measured by high performance liquid chromatography with fluorescence detection. Pharmacokinetic parameters calculated for the intravenous plasma drug concentration, time data revealed a terminal half-life of 12.9 +/- 6.0 h (mean +/- s.d.), clearance 98.7 +/- 47.3 1 h-1 m-2 and volume of distribution 1533 +/- 536 1 m-2. A bi-exponential equation corresponding to a two compartment open model best fitted the data. Half-life and clearance were not significantly different following oral administration. Bioavailability of oral idarubicin was 0.29 +/- 0.20 (mean +/- s.d.). There was a wide range of bioavailability between and within subjects. Plasma concentrations of idarubicinol (the only metabolite detected) rapidly exceeded those of the parent drug, and exposure to this metabolite was greater than to the parent drug. The mean half-life of idarubicinol was not significantly different after i.v. (63.1 +/- 28.2 h) and oral (45.8 +/- 16.0 h) administration. Much larger amounts of this metabolite were formed following the oral route of administration. This may have implications for the clinical use of this drug as idarubicinol may have appreciable cytotoxic activity.