Heterogeneity of the in vitro responses to glucocorticoids in acute leukemia.

In leukocyte population freshly isolated from the blood of 26 patients with acute leukemia, we have measured several parameters including glucocorticoid receptors, nucleoside incorporation, percentage of cells in S phase, and steroid-induced cell lysis. In addition, in some cases, the short-term response to steroid therapy was determined. Although, in all the patients studied, leukocytes were found to contain glucocorticoid receptors, we failed to demonstrate any correlation between the level of binding sites and the in vitro or in vivo response to glucocorticoids. This absence of correlation could be in part explained by the marked heterogeneity of the steroid response demonstrated in leukocyte subpopulations. It appears, however, that the degree of steroid action in vitro as well as the extent of spontaneous and dexamethasone-induced cell death may be related to the number of cells in the S phase of the cell cycle.

Modulation of 1-beta-D-arabinofuranosylcytosine metabolism by thymidine in human acute leukemia.

Twenty-seven patients with acute leukemia have been treated by sequential 6-day courses of thymidine (30 g/m2 by i.v. continuous infusion, days 1 and 4) and 1-beta-D-arabinofuranosylcytosine (ara-C) (200 mg/m2 by i.v. continuous infusion, days 2,3,5, and 6). Of 25 evaluable patients 4 achieved a complete remission: one of 9 for acute myelogenous leukemia; and 3 of 14 in the blastic crisis of chronic myelocytic leukemia. Six minor responses were also observed. Toxicity was mainly hematological and did not appear to be higher than that expected from ara-C alone. However, thymidine infusions gave rise to headache and somnolence. The clinical benefit of such treatment seems to be limited to the blastic crisis of chronic myelocytic leukemia. Parallel cytokinetic and biochemical studies were performed in order to assess the cytokinetic and metabolic changes induced by both drugs and to correlate them with the clinical response. Recruitment of cells into the S-phase fraction was observed following the first thymidine infusion in the two complete responders and in three of the five nonresponders studied. In contrast to this high pretherapeutic levels of S-phase fraction were observed in most minor responders and in some nonresponders with further decrease following the thymidine infusion. Recruitment of cells into S phase therefore appeared to be an important but not sufficient factor for prediction of complete response to ara-C. Responders in contrast to most nonresponders were characterized by a higher intracellular level of ara-C and its metabolites following the first 24-h infusion of the drug. Deoxythymidine triphosphate and deoxycytidine triphosphate pools were also measured before and during treatment in order to assess if nucleotide pool variations induced by the administration of thymidine can in fact correlate with the intracellular alteration in ara-C metabolism and with clinical response. The level of deoxycytidine triphosphate pools before treatment showed marked interpatient variations but did not correlate with response. As expected, thymidine infusion induced a rise in the deoxythymidine triphosphate pool and a decrease in deoxycytidine triphosphate. The pools, however, generally returned promptly to the pretherapeutic level 24 h after the end of the infusion of thymidine. There were no significant differences between responders and nonresponders in the modulation of these pools.

Multivariate analysis of prognostic factors in acute myeloid leukemia: value of clonogenic leukemic cell properties.

The initial clinical and biological parameters, including clonogenic leukemic cell (CFU-L) assay, were reviewed for their prognostic significance in a cohort of 188 adult patients with newly diagnosed untreated acute myeloid leukemia (AML). Almost all patients received induction therapy with daunorubicin (DNR) and cytarabine (Ara-C) according to the European Organization for Research and Treatment of Cancer (EORTC) AML 5 to AML 9 trials. Bone marrow samples from 116 representative patients were obtained for CFU-L assay with an efficiency percentage of 89.6%; 76 patients had a measurement of the CFU-L self-renewal capacity (second plating efficiency [PE2]) and 91 patients had CFU-L inhibition test after exposure to DNR and/or Ara-C. The prognostic significance of parameters such as age, hematological antecedent, WBC count, liver enlargement, and Auer rods is confirmed in the present study. Moreover, high platelet and polymorphonuclear counts appeared to be related to resistance to induction course. However, through multivariate analysis, CFU-L sensitivity to drugs and self-renewal capacity appeared to be major independent prognostic factors in AML. A low CFU-L inhibition in the presence of the DNR and Ara-C combination correlates with a poorer complete remission (CR) rate, but not with CR duration. Patients with the lower PE2 values experienced both higher CR rate and longer CR duration. The practical interest of CFU-L study remains to be defined but, at least, PE2 measurement could be considered in the future as a major variable in determining therapeutic aggressiveness.

Granulocyte-macrophage colony-stimulating factor associated with induction treatment of acute myelogenous leukemia: a randomized trial by the European Organization for Research and Treatment of Cancer Leukemia Cooperative Group.

PURPOSE: To assess the value of granulocyte-macrophage colony-stimulating factor (GM-CSF) for induction treatment of acute myeloid leukemia (AML), both for priming of leukemic cells and for acceleration of hematopoietic recovery. PATIENTS AND METHODS: GM-CSF was administered 5 micrograms/kg/d by continuous intravenous (i.v.) infusion during induction therapy with daunorubicin (DNR) (days 1 to 3) and cytarabine (ARA-C) (days 1 to 7). A total of 102 patients were randomized onto four arms, as follows: (1) GM-CSF 24 hours before and during chemotherapy (arm +/-); (2) GM-CSF after chemotherapy until day 28 or recovery of polymorphonuclear leukocytes (PMNs) (arm -/+);(3) GM-CSF before, during, and after chemotherapy (arm +/+); or (4) no GM-CSF (arm -/-). Stopping rules were applied in case of an initial WBC count greater than 30 x 10(9)/L or a secondary increase of circulating blast cells. Analyses were performed according to the intention-to-treat principle. RESULTS: The complete remission (CR) rates were 77% (arm -/-), 72% (arm +/-), 48% (arm -/+), and 46% (arm +/+). Patients randomized to receive GM-CSF after induction (arms -/+ and +/+) had a significantly lower CR rate (P = .008) and a trend toward accelerated recovery of neutrophils, but no fewer infections or induction deaths. The lower CR rate appeared to be related to an increased resistance rate, with persistent leukemia. The main side effects of GM-CSF were fluid retention and hypotension. CONCLUSION: GM-CSF administered during induction treatment of AML with a DNR/Ara-C combination did not provide any clinical benefit. Furthermore, there was a significant decrease in the CR rate with more persistent leukemia when GM-CSF was administered during the hypoplastic phase after the chemotherapy courses.

On the value of intensive remission-induction chemotherapy in elderly patients of 65+ years with acute myeloid leukemia: a randomized phase III study of the European Organization for Research and Treatment of Cancer Leukemia Group.

We report the results of a prospective study in patients more than 65 years of age in whom two different therapeutic strategies were compared: immediate intensive-induction chemotherapy (arm A) versus "wait and see" and supportive care and mild cytoreductive chemotherapy only for relief of progressive acute myeloid leukemia (AML)-related symptoms (arm B). The major objective of the study was to compare survival outcome of both regimens. Thirty-one patients on arm A received one or two courses of daunorubicin, vincristine, and cytarabine for remission induction followed by one additional cycle for consolidation in case of complete remission (CR). Among 29 patients on arm B, cytoreductive chemotherapy (hydroxyurea, cytarabine) had to be initiated for palliation of leukemia-associated complications in 21 patients at a median of 9 days after diagnosis. Overall survival duration for patients treated on arm A was significantly (P = .015) longer than the survival in arm B (median survival, 21 weeks v 11 weeks; projected survival at 2.5 years, 13% v 0%). Eighteen (58%) of arm A patients and none (0%) of arm B patients entered CR. Of the first group, projected disease-free survival at 2 years is 17%. The median percentages of days spent in the hospital by arm A and B patients were 55% and 50%, respectively. This study shows that a strategy based on modern supportive care and a wait and see approach yields extremely poor results. It is not superior in regard to the frequency of hospital admission and is inferior regarding survival outcome.

Response to pentostatin in hairy-cell leukemia refractory to interferon-alpha. The European Organization for Research and Treatment of Cancer Leukemia Cooperative Group.

Interferon-alpha (IFN-a) or 2'-deoxycoformycin (pentostatin; DCF) have each been shown to be highly active in hairy-cell leukemia (HCL). In this phase II study of the Leukemia Cooperative Group of the European Organization for Research and Treatment of Cancer (EORTC), the efficacy and toxicity of DCF were investigated in patients who were resistant to IFN-a treatment. Resistance was defined as: (1) progressive disease (PD) under IFN-a therapy for more than 2 months; (2) stable disease (SD) after more than 6 months of IFN-a treatment; (3) relapse within 3 months of discontinuing IFN-a; and (4) intolerance to IFN-a because of World Health Organization (WHO) grade 3 or 4 toxicity. DCF was applied at a dosage of 4 mg/m2 weekly x 3, then 4 mg/m2 every other week x 3. Responders were given a maintenance therapy once per month for a maximum of 6 months. At the time of report, 33 patients with resistant disease were evaluable for response and toxicity. Median duration of IFN-a therapy before DCF administration was 14.7 months (range, 1 to 41 months). Complete remissions (CRs) were achieved in 11 patients and partial remissions (PRs) in 15, resulting in a total response rate of 78.8%. Median interval between beginning of DCF therapy to best response was 3.9 months with a range from 2.0 to 7.0 months. Two patients who achieved PR have relapsed 7 and 14 months after cessation of DCF therapy. The median duration of response was over 11.5 months (range, over 3.0 to over 24.0 months). Three patients died within the first 6 weeks of DCF treatment: one of drug-unrelated cardiomyopathy and two of fungal pneumonia. The patients with early death (n = 3) and nonresponsive disease (n = 4) received IFN-a treatment for a longer period (median, 18.0 months) than did the 26 responsive patients (median, 10.0 months). Major side effects included nausea, skin rash, and infections and were otherwise mild. Thus, DCF is highly active in patients with HCL resistant to IFN-a.

Extended versus involved fields irradiation combined with MOPP chemotherapy in early clinical stages of Hodgkin's disease.

From 1976 to 1981, 335 patients with untreated Hodgkin's disease, clinical stages I, II, and IIIA, have been treated by MOPP (nitrogen mustard, vincristine, procarbazine, prednisone) chemotherapy, three to six cycles according to the prognostic factors, combined with radiotherapy. Irradiation was always performed after the first three cycles of chemotherapy, and was randomized between extensive radiotherapy, ie, mantle and paraaortic areas for supradiaphragmatic presentations, and radiotherapy restricted to the involved areas. No significant difference was observed between the two randomized branches for the disease-free survival (86% after six years in the involved field branch v 90% in the extended field branch), and none for the overall survival. Most of the relapses occurred in nonirradiated areas in the first group, and in irradiated areas in the second. Relapses were especially frequent in the IIE stages with pulmonary extension; extranodal relapses occurred with osseous and cutaneous localizations. Two cases of secondary leukemia were observed after three- or six-cycle MOPP plus radiotherapy limited to the involved areas.

Mitoxantrone versus daunorubicin in induction-consolidation chemotherapy--the value of low-dose cytarabine for maintenance of remission, and an assessment of prognostic factors in acute myeloid leukemia in the elderly: final report. European Organization for the Research and Treatment of Cancer and the Dutch-Belgian Hemato-Oncology Cooperative Hovon Group.

PURPOSE AND METHODS: Optimization of remission-induction and postremission therapy in elderly individuals with acute myeloid leukemia (AML) was the subject of a randomized study in patients older than 60 years. Remission-induction chemotherapy was compared between daunomycin (DNR) 30 mg/m2 on days 1, 2, and 3 versus mitoxantrone (MTZ) 8 mg/m2 on days 1, 2, and 3, both plus cytarabine (Ara-C) 100 mg/m2 on days 1 to 7. Following complete remission (CR), patients received one additional cycle of DNR or MTZ chemotherapy and were then eligible for a second randomization between eight cycles of low-dose (LD)-Ara-C 10 mg/m2 subcutaneously every 12 hours for 1 2 days every 6 weeks or no further treatment. RESULTS: A total of 242 patients was randomized to DNR and 247 to MTZ. Median age of both study groups was 68 years. Secondary AML was documented in 26% and 25% of patients in either arm. The probability of attaining CR was greater (P = .069) with MTZ (47%) than with DNR (38%). Median duration of neutropenia was 19 (DNR) and 22 days (MTZ). The greater response rate to MTZ therapy correlated with reduced occurrence of chemotherapy resistance (32% v 47%, P = .001). With a median follow-up of 6 years, 5-year disease-free survival (DFS) is 8% in each arm. Overall survival estimates are not different between the groups (6% v 9% at 5 yrs). Poor performance status at diagnosis, high WBC count, older age, secondary AML, and presence of cytogenetic abnormalities all had an adverse impact on survival. Secondary AML and abnormal cytogenetics predicted for shorter duration of CR. Among complete responders, 74 assessable patients were assigned to Ara-C and 73 to no further therapy. Actuarial DFS was significantly longer (P = .006) for Ara-C-treated (13% [SE = 4.0%] at 5 years) versus nontreated patients (7% [SE = 3%]), but overall survival was similar (P = .29): 18% (SE = 4.6%) versus 15% (SE = 4.3%). Meta-analysis on the value of Ara-C postremission therapy confirms these results. CONCLUSION: In previously untreated elderly patients with AML, MTZ induction therapy produces a slightly better CR rate than does a DNR-containing regimen, but it has no significant effect on remission duration and survival. Ara-C in maintenance may prolong DFS, but it did not improve survival.

Expression of multidrug resistance-associated protein (MRP) and multidrug resistance (MDR1) genes in acute myeloid leukemia.

The frequency, prognostic value and interrelation of MRP and MDR1 gene expressions were investigated by quantitative reverse transcription polymerase chain reaction (RT-PCR) in 91 cases of de novo acute myeloid leukemia (AML), of which 51 were newly diagnosed, 21 were relapsed, and 19 were refractory patients. As compared with normal bone marrow cells and peripheral granulocytes, an overexpression of MRP gene was found in 24% (22 of 91) cases of de novo AML. The incidence of MRP gene overexpression tended to be higher in relapsed patients than in newly diagnosed patients (38 vs 18%, P = 0.063). In 52 evaluable newly diagnosed and relapsed patients treated with MDR-related drugs, both MRP and MDR1 gene overexpressions correlated to a higher rate of emergence of clinical drug resistance (83 vs 22%, P = 0.005; and 67 vs 24%, P = 0.045, respectively). A positive correlation was found between MRP and MDR1 gene overexpressions (R = 0.53, P < 0.001). Analysis of 46 evaluable MDR1-negative cases revealed a trend for higher resistant disease rate in MRP-positive patients as compared with MRP-negative patients (100 vs 20%, P = 0.053). These data suggest that MRP, like MDR1, may have an important negative impact on the outcome of chemotherapy, and that there may be a common mechanism of induction for the overexpression of these two genes.

Role of MRP1 in multidrug resistance in acute myeloid leukemia.

The best characterized resistance mechanism in adult acute myeloid leukemia (AML) is the one mediated by the MDR1 gene which has been shown to be associated with poor outcome. However, alternative proteins such as the more recently recognized multidrug-associated protein (MRP1), may also contribute to the resistance to anthracyclines and etoposide in AML. Recently, the role of this protein was discussed and was unclear in AML. However, recent data concerning the functionality and the modulation of the activity of MRP1 may elucidate its role in comparison with other mechanisms of resistance. In this paper, we will review these recent data concerning the role of MRP1 in adult AML.

Daunorubicin uptake by leukemic cells: correlations with treatment outcome and mdr1 expression.

The in vitro daunorubicin (DNR) cell uptake was investigated by flow cytometry in K562/DOX resistant cell line and in 42 patients with acute myeloid leukemia (AML). The proportion of cells able to take up DNR was higher in untreated patients (50% +/- 30) than in previously treated patients (31% +/- 31) (p = 0.04). We noted a good correlation (p < 0.001) between the drug uptake after exposure to 0.1 microM DNR and achievement of complete remission. Cyclosporin A (CsA, 1 microgram/ml) and verapamil (5 micrograms/ml), but not cefoperazone (10 mM), completely reversed (CsA) or partially reversed (verapamil) the DNR efflux from K562/DOX mdr1(+) cell line. CsA significantly increased (p < 0.01) the DNR uptake of fresh leukemic cells, but not consistently, with no relationship to mdr1 mRNA cellular level. This absence of correlation was explained by the fact that several patients with no mdr1 gene expression exhibited a low in vitro DNR uptake, showing that the MDR phenotype is not the only mechanism responsible for the alteration of DNR pharmacokinetics in AML.

Relevance of mdr1 gene expression in acute myeloid leukemia and comparison of different diagnostic methods.

In an attempt to determine the incidence and clinical relevance of mdr1 gene expression in acute myeloid leukemia (AML), we examined 126 specimens obtained from adult patients with de novo AML by slot blot and immunocytochemistry. We found a high incidence of mdr1 gene expression in newly diagnosed patients (27% by immunocytochemistry and 43% by slot blot). No difference was observed between newly diagnosed patients and relapsed patients. However, patients with resistant disease showed statistically higher incidence of mdr1 gene expression compared to the untreated and relapsing patients (60% versus 27% by immunocytochemistry, p 0.005; and 73% versus 45% by slot blot, p less than 0.05). The expression of mdr1 gene correlated significantly with clinical drug resistance: 62% of patients positive for mdr1-mRNA and 68% of patients positive for P-glycoprotein (P-gp) eventually developed resistance to chemotherapy, while this was the case for a lower percentage of patients who did not express mdr1 gene (only 23% by slot blot analysis, p = 0.0052, or 24% by immunocytochemistry, p = 0.0009). A combined parameter, mdr1-mRNA/P-gp, had a very high prognostic value in terms of specificity and sensitivity. All nine patients (100%) who were mdr1-mRNA+/P-gp+ progressed to clinical drug resistance afterward, whereas 11 of 13 (85%) patients who were mdr1-mRNA-1 P-gp- entered complete remission and only two patients later developed drug resistance (p = 0.0005). It could thus be used as a reliable parameter in clinical settings.

Cost of complete remission induction in acute myeloblastic leukemia: evaluation of the cost-effectiveness of a new drug.

The use of new drugs in the treatment of AML could dramatically increase the cost of induction chemotherapy. To evaluate the cost-effectiveness of such new drugs, the overall cost to achieve complete remission (CR) with treatments including these drugs has to be compared to the cost of the daunorubicin-cytosine arabinoside (DNR-AraC) association, considered as the reference treatment. A retrospective analysis of charts from 15 patients treated with DNR-AraC was used to identify 228 items of cost, including general cost, diagnostic, supportive care, and chemotherapy. Eleven patients underwent CR after one course of chemotherapy for a cost of US$16,701 +/- 4451, and four patients achieved CR after two courses for a cost of US$37,130 +/- 4923. The chemotherapy represented only 1.4% of the total cost, supportive care 25% and general cost 56%. According to these data, the projective cost of a treatment with mitoxantrone instead of DNR was simulated in 40 untreated patients with AML. The better rate of CR obtained after one course of chemotherapy leads to a saving of 9% (US$1261) per patient, despite the higher cost of chemotherapy. Cost-effectiveness evaluation should be included in the clinical study of trials with new drugs.

Lung resistance protein (LRP) gene expression in adult acute myeloid leukemia: a critical evaluation by three techniques.

The role of LRP in clinical drug resistance in acute myeloid leukemia (AML) is controversial. We therefore compared multiple assays, including RT-PCR, immunocytochemistry (ICC) and flow cytometry (FC), in 10 cell lines and in 47 fresh and thawed AML cells in order to validate and to quantitate measures for LRP phenotype detection. We also compared different ways of expressing the results. Lastly, in cell lines, we analyzed the 50% lethal concentration (LC50), by MTT assay, of cisplatin which could estimate the functionality of LRP. The reproducibility of LRP detection measured by RT-PCR, ICC and FC was good. In the same way, within the same technique, there was good correlation between the different methods of expressing the results of LRP level. Therefore, the discrepancies noted with the three techniques used were neither a problem of reproducibility nor a problem of results expression. On the other hand, there was only a correlation between ICC and FC, and no correlation between RT-PCR and LRP protein detection techniques. Therefore, RT-PCR is probably not the optimal technique for LRP detection. We have shown in 10 cell lines a higher correlation between FC and LC50 of cisplatin than between ICC and LC50 of cisplatin and no correlation between RT-PCR and LC50 of cisplatin. For five patients, there was a dissociation between ICC and FC. Four patients were positive by FC and negative by ICC and only one patient was negative by FC and positive by ICC. Therefore, if in vitro resistance to cisplatin represents the functionality of LRP, we recommend the use of FC rather than ICC to detect LRP expression. Besides the measurement of LRP as a diagnostic tool in the evaluation of resistance to chemotherapy in patients with AML, we urgently need to establish a functional test in order to assess LRP activity.

Fluorescence in situ hybridization analysis of minute marker chromosomes in leukemia with monosomy 7.

Monosomy 7 was detected in bone marrow cells from three patients, one with myeloid leukemia, and two others with myelodysplastic syndrome following previous chemotherapy. Fluorescence in situ hybridization (FISH), carried out with an alphoid DNA probe specific for chromosome 7 centromere, showed that a small marker chromosome present in the tumor cells' karyotype of the three patients, was derived from the missing chromosome 7. In two cases, the marker was a ring chromosome, whereas in the third case it was a tiny dot-like chromosome, unnoticed at first examination on R-banded metaphases. In the three cases, the marker was lost in a proportion of tumor cells. FISH experiments suggested that the marker centromere had undergone structural alterations, with a fluorescence pattern distinct from a normal one. On the whole, these data suggest that: firstly, leukemia-associated monosomy 7 results, in a proportion of cases, from a structural event rather than from simple loss of a whole chromosome 7; secondly, interpretation of interphase FISH must be cautious in monosomy 7 evaluation; and thirdly structural alteration of the chromosome 7 derivative alphoid DNA could explain its propensity to segregate unequally and to be lost at mitosis.

Alterations of cyclin-dependent kinase 4 inhibitor (p16INK4A/MTS1) gene structure and expression in acute lymphoblastic leukemias.

The cyclin-dependent kinase 4 (cdk4) inhibitor (p16INK4/MTS1/CDKN2) gene has been recently identified as a putative tumor suppressor gene because of the high frequency of homozygous deletion observed in numerous human tumor cell lines, including leukemias. However, results obtained from uncultured tumor samples have led to discussion of the relevance of these findings. Using reverse transcriptase polymerase chain reaction (RT-PCR) and Southern blot analysis, we have investigated p16INK4A gene at both RNA and genomic levels in various types of leukemias: acute myeloid leukemia (AML) (n = 23); acute lymphocytic leukemia (ALL) (n = 22) and B cell chronic lymphoproliferative disorders (CLPD) (n = 33). p16INK4A mRNA expression was not found in only 1/20 AML and 2/23 CLPD samples. Conversely, p16INK4A mRNA was not detected in 5/17 ALL cases, and intensity of PCR products were barely detectable in seven additional cases, possibly related to the contamination by normal cells in some cases. By Southern blotting, a homozygous deletion of p16INK4A gene was found in 6/17 ALL cases (35%) among which 4/6 were negative or weakly positive by RT-PCR assay. None of the five AML and 20 CLL samples studied had p16INK4A deletion. Sequence analysis of p16INK4A exon 2 did not show point mutation in two of these cases lacking mRNA expression. Our data provide further evidence that among hematological malignancies, ALL are the most likely to be associated with p16INK4A inactivation, mainly by homozygous gene deletion. Since most hematological malignancies-except ALL-are infrequently associated with p16INK4A and retinoblastoma (Rb) gene alteration it seems worthwhile to explore cdk4 and cdk6 expression to determine whether or not the disruption of the p16INK4A/Rb/cdk4/cdk6 regulatory loop might play a role in their pathogenesis.

Prognostic value of clonogenic assay for induction and duration of complete remission in acute myelogenous leukemia.

The validity of an in vitro clonogenic drug sensitivity assay to predict the induction and the duration of complete remission was evaluated in a group of 81 patients with acute myelogenous leukemia treated with chemotherapy including an anthracycline drug (daunorubicin or adriamycin) and cytosine arabinoside (Ara-C). The inhibition of bone marrow clonogenic leukemic cells by in vitro exposure to anthracyclines 10(-5) and 10(-6) M, Ara-C 10(-5) M, and daunorubicin 10(-6) M + Ara-C 10(-7) M was significantly correlated with the achievement of a complete remission, but not with the duration of remission. A high second plating efficiency was correlated with short duration of complete remission, reflecting the poor prognosis of a high self-renewal capacity.

Effect of the multidrug inhibitor GG918 on drug sensitivity of human leukemic cells.

The drug GG918 has been specifically developed for overcoming MDR phenotype and is now in use in clinical trials. In this study, the effects of GG918 on leukemic cell were investigated using a 3 day MTT assay. Results showed that, in a highly resistant P-gp(+) leukemic cell line, 0.1 microM of GG918 gives rise to a 40-fold sensitization to daunorubicin (DNR) (residual resistance: 2.1), a 57-fold sensitization to mitoxantrone (residual resistance: 1.5), and a 3.3-fold sensitization to idarubicin (residual resistance: 2.9). When human AB serum was added to the incubation medium, 1 microM of GG918 was needed to observe the full P-gp modulation potency described above. The effect of 1 microM of GG918 was tested on 27 samples of poor prognosis acute leukemia (25 AML, two ALL). DNR sensitization (using the MTT assay) and modulation of rhodamine 123 uptake were monitored and used as criteria for comparing the in vitro modulation potency of this new compound to the potency of 10 microM of verapamil, which was used as reference. A good correlation (r = 0.8, P = 0.001) was observed between the results of the two tests. Eleven out of the 26 cases tested were MDR1(+) (42%), and showed a higher IC50 for DNR than the negative cases (861 +/- 1284 nM vs 187 +/- 246 nM, P = 0.05). GG918 was able to modulate the in vitro resistance to DNR in eight cases (seven MDR1(+), no MDR1(-), one non-tested). Verapamil did not increase DNR toxicity in four of these eight cases, but was more efficient in one other MDR1(+) case. In conclusion, the DNR sensitivity of the majority of the fresh AML samples expressing P-gp could be modulated in vitro by 1 microM of GG918.

Has the prognosis of adult patients with acute myeloid leukemia improved over years? A single institution experience of 784 consecutive patients over a 16-year period.

We reviewed the reports of 784 consecutive patients admitted to our department for newly diagnosed acute myeloid leukemia (AML) over a 16-year period. Median, 5-year and 10-year overall survivals were 9. 5 months, 17.3% and 11.7% respectively. Induction treatment (698 patients) resulted in 50% complete remissions (CR) (from 26.5% in secondary AML to 81.2% in patients <60 years with de novo AML). Period of diagnosis (1980-84/85-89/90-95) demonstrated a major significance for CR achievement and OS in multivariate analysis. In patients >/=60 years (372), CR rate increased (25% to 36.8%, P = 0. 03), and 5-year OS (3.7% to 10.6%, P = 0.022) improved, probably due to an increase in the proportion of patients administered conventional combined chemotherapy (54.5% to 83.8%, P < 0.0001). In younger patients CR rate continuously increased (61.5% to 74.8%, P = 0.028) with an associated improvement of 5-year OS (19.2% to 35.4%). No significant change in DFS and CR durations was observed. This large single center study on a large cohort of unselected AML patients reflects the improvement achieved in the management of AML patients, likely due to improvement of supportive care practices, administration of conventional induction to more elderly patients, and intensification of induction and post-remission treatments in patients <60 years.

Treatment of patients with acute promyelocytic leukemia. The EORTC-LCG experience. EORTC Leukemia Cooperative Group.

Acute promyelocytic leukemia (M3) is, as one of the FAB subtypes of AML, included in the EORTC/GIMEMA AML-8A and 8B randomized trials. In these trials 1519 patients were included, 477 of them in non-Italian EORTC-LCG centers and 1042 in GIMEMA centers. A total of 80 patients were classified as M3 including 18 patients with M3-variant. Thirty-nine were male and 41 female. Ages ranged from 15 to 59 years; 25 (31.3%) of them were younger than 30, 34 (42.5%) between 30 and 45, and 21 (26.3%) older than 45 years of age. 56.3% of the patients had leukocytes less than 5 x 10(9)/l at the time of diagnosis vs. 24.9% of the patients belonging to the other FAB subtypes. Remission induction consisted of a standard protocol with 3 days daunorubicin and 7 days of cytosine arabinoside. Forty-three patients (53.8%) achieved a complete remission compared to 64.6% of the remaining AML patients. After salvage treatment this percentage increased to 70%, which is the same as for the other AML subtypes. Thirteen (16.3%) patients died during remission induction, mainly due to hemorrhagic complications. This percentage is significantly higher than the death rate (9.1%) in the other FAB subtypes of AML. All patients received one course of consolidation treatment. Post consolidation treatment could be either standard maintenance, intensive consolidation courses, autologous or allogeneic transplantation, according to the guidelines of the treatment protocols. At present, relapses almost all in the bone marrow, are seen in only 34.9% of the M3 patients, compared to 48.4% in the remaining AML patients. Disease-free survival for patients less than 45 years of age with the M2 and M3 subtypes was approximately 50% at 3 years compared to 30-40% for the other FAB subtypes. Despite the higher death rate during induction, the long-term survival results were better for M3 patients in comparison with the remaining AML patients. The projected survival at 3 years was 50% for M3 patients vs. 38% for remaining patients.