Search

High-dose methotrexate (HD-MTX) with leucovorin rescue is a component of therapy in children with acute lymphoblastic leukaemia. Since MTX toxicity is related to drug exposure, a monitoring of serum MTX concentrations at H24, H48, H72 and until the concentration is less than 0.2 micromol/L is commonly performed. However, a number of patients may reach concentrations of less than 0.2 micromol/L long before the next sampling is scheduled. The aim of our study was to develop a Bayesian method predicting the time at which MTX concentration reaches 0.2 micromol/L in order to decrease the number of samples drawn and to allow for a more rapid patient discharge. Methotrexate population parameters were estimated from a retrospective analysis of 60 infusions in 23 children and MTX concentrations were predicted from an independent set of 20 courses in 14 children with a Bayesian approach using either one (H48) or two (H24 and H48) samples. The following population parameters were obtained using a two-compartment model: CL = 3.51 L/h (inter-individual variability: 66%), Vd = 8.67 L (58%), k12 = 0.0044 h(-1)(105%), k21 = 0.039 h(-1)(25%). Clearance and Vd were found to increase with weight and age respectively. Both sampling schedules tested for the Bayesian estimation enabled accurate prediction of concentrations and provided satisfactory precision despite a small bias. When considering the ability to predict the time at which the threshold was reached, the one-sample (H48) schedule gave the best results. We conclude that a sampling schedule involving only one sample and Bayesian parameter estimation may be able to predict the delay necessary to reach 0.2 micromol/L in each individual.

A study of CFU-GM sensitivity to mafosfamide was carried out in 67 candidates for ABMT. A lethal dose 95 (LD95) was calculated from the dose-response curve. Despite standardized treatment conditions of marrow buffy-coat cells, LD95 values that were normally distributed (median 100 micrograms/ml; mean +/- SEM 95.6 +/- 4.0 micrograms/ml) varied considerably from patient to patient (range 30-160 micrograms/ml). Three independent factors appeared to confer greater sensitivity of CFU-GM: low patient age, low CFU-GM rate in treated cells and prolonged delay of CFU-GM sensitivity test from last chemotherapy course. In contrast, sex, pathology, disease status, number of previous chemotherapies and use of CY before the test did not influence CFU-GM sensitivity. Forty-six patients were autografted with mafosfamide-treated marrows according to their LD95. The mean percentage of CFU-GM effectively recovered after graft purging was 3.96 +/- 2.09%. All patients engrafted well and their peripheral blood cell recoveries were correlated with graft CFU-GM content evaluated before purging but not after purging or after freezing. In multivariate analysis, this parameter remained the only factor predicting hematopoietic recovery among other patient variables such as sex, age, pathology, disease status, previous chemotherapies or TBI in conditioning regimens. In a subgroup of 39 patients with lymphoid malignancies compared with 25 patients autografted for non-Hodgkin's lymphomas with unpurged marrows, the delay in days (medians) was similar for leukocytes1 x 10(9)/l (19 vs 17 days) and for neutrophils0.5 x 10(9)/l (18 vs 17 days) while it was longer for platelets50 x 10(9)/l (34 vs 128 days).(ABSTRACT TRUNCATED AT 250 WORDS)

In an attempt to improve in vitro pharmacological purging of autologous grafts, the ability of doxorubicin (DOX), alone and in combination with mafosfamide (AZ), to eliminate tumor cells from human bone marrow was assessed. HL60 and Raji cells were mixed with a 20-fold excess of normal marrow cells and were incubated either with DOX (0.4-3.2 micrograms/ml) for 1 h or AZ (20-140 micrograms/ml) for 30 min or both drugs sequentially. Cytotoxicity was evaluated on tumor cells and GM-CFU by clonogenic assays and on earlier hemopoietic progenitors by liquid long-term marrow cultures (LTMC) for 5 weeks. DOX at 3.2 micrograms/ml and AZ at 140 micrograms/ml spared 1.08 and 1.23% of GM-CFU respectively, and yielded similar tumor cell log-kills for HL60 cells (3.04 and 2.95) and Raji cells (3.24 and 3.40). With the combination of AZ and DOX, the best therapeutic index was observed when the cells were incubated with AZ prior to DOX. Under these conditions, AZ at 80 micrograms/ml together with DOX at 1.6 micrograms/ml significantly increased log-kill values for HL60 cells to 3.96 by a synergistic effect and for Raji cells to 3.85 by an additive effect. In LTMC, GM-CFU recovery after treatment with AZ alone and with the combination of AZ and DOX was 59.9 and 20.0%, respectively, while it was 7.9 and 2.9% at culture initiation. These results suggest that the purging efficiency of DOX is comparable to that of AZ and may be enhanced by combination with AZ.

Thirty-one patients, 13 adults and 18 children, were included in a phase II study of combined treatment with CDDP 40 mg/m2 and VP16 100 or 200 mg/m2 for 5 days. Fourteen patients were primary refractory to front-line treatment and 17 were treated at relapse (9 on therapy, 8 off therapy). Four were low-grade follicular lymphomas, 7 intermediate grade lymphomas, and 20 high grade lymphomas. One of the 14 primary refractory cases responded (CR) whereas 3 PR and 10 CR were observed among the 17 relapses. Toxicity was acceptable. 9 patients are still alive after bone marrow transplantation (median survival, 16 months). This combination is an effective salvage regime before autologous bone marrow transplantation for relapsed NHL, but cannot be recommended for progression on front-line therapy.

Changes in nutritional status at the initial phase of treatment of cancers and malignant blood diseases were evaluated in 32 male patients (mean age 58 +/- 18 years) examined during three 4-day stays in hospital (T0, T1, T2) at 2 months' interval. On the first day of each stay the following parameters were measured: food intake (kcal/day), weight (kg), squared height (m), fat mass (kg) obtained by measuring 4 skin folds and using Durnin's tables, brachial muscle area (cm2) and total skeletal muscle mass (kg) calculated from Heymsfield's equations. On the third and fourth days, after 48 hours of meat-free and fish-free diet, 3-methylhistidine (mmol/g creatininuria) and creatinine (mg) were measured in urine, and the urinary creatinine/height ratio (mg/cm/day) was calculated. Full anthropomorphic measurements were performed on 19/32 patients and complete measurements of 3-methylhistidine and the urinary creatinine/height ratio in 9/32 patients. Subsequent examinations revealed a decrease in brachial muscle area, total skeletal muscle mass and urinary creatinine/height ratio which, together with an increase in baseline 3-methylhistidine, confirmed the loss of muscle mass. Mean losses of muscle and fat were 6 p. 100 between T1 and T0 and 7 p. 100 between T2 and T0 for the muscle mass, and 9 p. 100 between T2 and T0 for the fat mass. These losses of body mass occurred very early, with significant differences between T1 and T0 and between T2 and T0. They suggest that protein-calorie malnutrition develops at a very early stage in patients treated for cancer or malignant blood disease.