Effect of priming with granulocyte-macrophage colony-stimulating factor in younger adults with newly diagnosed acute myeloid leukemia: a trial by the Acute Leukemia French Association (ALFA) Group.

In a multicenter trial, 259 young adults (15-49 years) with newly diagnosed acute myeloid leukemia (AML) were first randomized to receive a timed-sequential induction regimen given either alone (135 patients) or concomitantly with granulocyte-macrophage colony-stimulating factor (GM-CSF) (124 patients). Patients reaching complete remission (CR) were then randomized to compare a timed-sequential consolidation to a postremission chemotherapy including four cycles of high-dose cytarabine followed by maintenance courses. In the appropriate arm, GM-CSF was given concurrently with chemotherapy during all cycles of consolidation. CR rates were significantly better in the GM-CSF arm (88 vs 78%, P<0.04), but did not differ after salvage. Patients receiving GM-CSF had a higher 3-year event-free survival (EFS) estimate (42 vs 34%), but GM-CSF did not impact on overall survival. Patients with intermediate-risk cytogenetics benefited more from GM-CSF therapy (P=0.05) in terms of EFS than patients with other cytogenetics. This was also confirmed when considering only patients following the second randomization, or subgroups defined by a prognostic index based on cytogenetics and the number of courses required for achieving CR. Priming of leukemic cells with hematopoietic growth factors is a means of enhancing the efficacy of chemotherapy in younger adults with AML.

Autologous or allogeneic stem cell transplantation as post-remission therapy in refractory or relapsed acute myeloid leukemia after highly intensive chemotherapy.

Post-remission options were compared in a population of 262 relapsing and refractory acute myeloid leukemia patients achieving complete remission (CR) after the same re-induction according to etoposide - mitoxantrone - cytarabine (EMA) trials. The selection of post-remission therapy depended on trial recommendations, age, performance status, and availability of an HLA-identical sibling. One hundred and thirty patients received chemotherapy consolidation courses, 50 received autologous stem cell transplantation (SCT), and 43 underwent allogeneic bone marrow transplantation (BMT), while 39 did not receive any additional therapy. The preliminary analysis identified 3 favorable prognostic factors correlated with event-free survival (EFS): M3 subtype, previous CR duration > 1 year, and transplantation. Three year EFS was 68 vs. 23% with autologous SCT and allogeneic BMT in M3 patients and, respectively, 41 vs. 20% in non-M3 patients. Three year probabilities of treatment-related mortality were 11 and 47%, respectively. A statistical model was conceived with adjustment on prognostic factors and post-remission option. In the multivariate analysis, autologous SCT appeared significantly better than allogeneic BMT (P < 0.01) or chemotherapy (P = 0.001), while allogeneic BMT was not statistically different than chemotherapy. This indicates a high treatment-related toxicity with allogeneic BMT in patients re-induced by highly intensive chemotherapy, and therefore a tendency for a better outcome with autologous SCT as post-remission treatment in those patients.

Effect of valproate, sodium 2-propyl-4-pentenoate and sodium 2-propyl-2-pentenoate on renal substrate uptake and ammoniagenesis in the rat.

Experiments were carried out in the intact functioning rat kidney to study the effect of valproate (VPA), a widely used antiepileptic drug and an hyperammonemic agent, but usually without clinical relevance, and of two of its metabolites, sodium 2-propyl-4-pentenoate (4-en-VPA) and sodium 2-propyl-2-pentenoate (2-en-VPA), on the renal production of ammonia and on the renal uptake of glutamine, glutamate and of inhibitors of renal ammoniagenesis; mainly lactate, fatty acids, ketone bodies and alpha-ketoglutarate. Administration of VPA and 4-en-VPA stimulated the uptake of glutamine and glutamate and the production of ammonia by the rat kidney, resulting in an increase in the renal venous release of ammonia and in a hyperammonemia. By contrast, no hyperammonemia was observed after the administration of 2-en-VPA which stimulated renal ammoniagenesis to a lesser extent than VPA and 4-en-VPA, resulting in no stimulation of the renal venous release of ammonia. The three compounds tested caused, in a qualitatively different but, in terms of substrate carbons, in a quantitatively similar manner, a significant diminution of the renal uptake of fatty acids, ketone bodies and alpha-ketoglutarate. These results suggest that, in the rat kidney, VPA, 4-en-VPA and 2-en-VPA stimulate the production of ammonia at least in part by reducing the renal uptake and metabolism of ammoniagenesis inhibitors; the more potent stimulation of renal ammoniagenesis caused by VPA and 4-en-VPA also suggest that these compounds exert their stimulatory effect by an additional mechanism.

Substrate uptake and utilization by the kidney of fed and starved rats in vivo.

In order to obtain information (1) on the quantitative contribution of various circulating substrates to renal metabolism and (2) on the relative importance of net luminal and basolateral transport for substrate uptake, we have precisely quantified the renal blood flow, the urinary flow, and the rates of substrate handling by the kidney of anesthetized fed and 72-hour-starved rats. For this, the concentration of twelve metabolites were simultaneously measured in arterial and venous whole blood and plasma as well as in urine of each rat thanks to the use of microassays based on enzymatic cycling. In fed rats, the main potential energy sources were glucose and lactate followed by fatty acids, ketone bodies, citrate and glycerol. Starvation caused a large increase in renal uptake and metabolism of fatty acids, ketone bodies, glutamine and glycerol, and a large inhibition of lactate utilization. The net peritubular uptake of acetoacetate, citrate, glycerol and free fatty acids demonstrated in both nutritional states was increased by starvation only for glycerol and free fatty acids; net peritubular efflux of both beta-hydroxybutyrate and ammonium ions was stimulated whereas that of glutamine was converted into net peritubular uptake by starvation.

Salvage by timed sequential chemotherapy in primary resistant acute myeloid leukemia: analysis of prognostic factors.

Primary resistant acute myeloid leukemia (AML) has a very poor prognosis. Etoposide-mitoxantrone-cytarabine (EMA) timed sequential chemotherapy including a first sequence combining mitoxantrone (12 mg/m(2) per day over 3 days) with cytarabine (500 mg/m(2) per day over the same period), and a second sequence consisting in etoposide (200 mg/m(2) per day for 3 days) and cytarabine as in the first sequence, has been proposed as a salvage regimen. Over a 10-year period, 66 primary resistant AML patients have been treated by EMA salvage chemotherapy. All patients displayed intermediate- or high-risk karyotypic abnormalities. Of the 66 patients, 24 [36%, 95% confidence interval (CI): 25-49%] achieved complete remission (CR). Thirty-eight patients were resistant to EMA chemotherapy and four patients died from toxicity during aplasia. After CR achievement, 18 patients received consolidation therapy. Five patients with an HLA-identical sibling donor underwent allogeneic stem cell transplantation (SCT), one patient received autologous SCT, two patients received a second course of EMA chemotherapy, and ten were scheduled for 6-monthly maintenance courses (mini-EMA). Median follow-up was 7.3 years. At the time of analysis, 21 of the 24 patients (87%) who achieved CR have relapsed. Median disease-free survival (DFS) was 5 months (95% CI: 4.3-7.7 months). Median overall survival (OS) was 5 months (95% CI: 3.8-6.7 months). There were only two long-term remitters (3%). In the univariate analysis, CR achievement was mainly related to white blood cell (WBC) count at the time of starting salvage therapy with poorer outcome for patients with more aggressive leukemia (WBC count > or =10 x 10(9)/l) (CR rates: 50% vs 10%, p<0.001). Overall survival was also influence by WBC count (median OS: 7.2 months vs 2.8 months, respectively, for WBC or =10 x 10(9)/l, p<0.0001). Initial karyotype was not a significant prognostic factor either for CR achievement or for DFS or OS when comparing patients with normal karyotype and those with chromosomal abnormality. In multivariate analysis, WBC count less than 10 x 10(9)/l with the absence of circulating blasts at the time of starting salvage therapy appeared to be of favorable prognostic value for CR achievement ( p=0.002), while WBC count less than 10 x 10(9)/l appeared to be of favorable prognostic value for survival ( p<0.0001). Using these two objective parameters of proven significance, we devised a prognostic system of immediate clinical utility for prognostic stratification and risk-adapted therapeutic choices. Patients with both factors (WBC count <10 x 10(9)/l and no circulating blasts) or with at least one at the time of starting salvage therapy had a CR rate of 50% and were therefore candidates for intensified post-remission therapy. All other patients displayed a very poor outcome and must be oriented after failure of first-line therapy to alternate therapeutic programs based on investigational drugs.

Advantages and limitations of the use of isolated kidney tubules in pharmacotoxicology.

Among the cellular models used in in vitro renal pharmacotoxicology, isolated kidney tubules, used as suspensions mainly of proximal tubules, offer important advantages. They can be prepared in large amounts under nonsterile conditions within 1-2 h; thus, it is possible to employ a great number of experimental conditions simultaneously and to obtain rapidly many experimental results. Kidney tubules can be prepared from the kidney of many animal species and also from the human kidney; given the very limited availability of healthy human renal tissue, it is therefore possible to choose the most appropriate species for the study of a particular problem encountered in man. Kidney tubules can be used for screening and prevention of nephrotoxic effects and to identify their mechanisms as well as to study the renal metabolism of xenobiotics. When compared with cultured renal cell, a major advantage of kidney tubules is that they remain differentiated. The main limitations of the use of kidney tubules in pharmacotoxicology are (1) the necessity to prepare them as soon as the renal tissue sample is obtained; (2) their limited viability, which is restricted to 2-3 h; (3) the inability to expose them chronically to a potential nephrotoxic drug; (4) the inability to study transepithelial transport; and (5) the uncertainty in the extrapolation to man of the results obtained using animal kidney tubules. These advantages and limitations of the use of human and animal kidney tubules in pharmacotoxicology are illustrated mainly by the results of experiments performed with valproate, an antiepileptic and moderately hyperammonemic agent. The fact that kidney tubules, unlike cultured renal cells, retain key metabolic properties is also shown to be of the utmost importance in detecting certain nephrotoxic effects.