Evaluation Of Acute Myeloid Leukemia Research Articles

Abstract 1655: Discovery and development of IACS-010759, a novel inhibitor of Complex I currently in phase I studies to exploit oxidative phosphorylation dependency in acute myeloid leukemia and solid tumors

Abstract Over the past few years we and others reported that specific populations of tumor cells including AML, subsets of lymphoma, glioblastoma, triple negative breast cancer (TNBC), melanoma and pancreatic ductal adenocarcinoma (PDAC) are highly dependent upon oxidative phosphorylation (OXPHOS) to meet their energy and biomass needs. Inhibition of OXPHOS in the context of these dependent tumor populations represents therefore an exciting therapeutic opportunity. Through an extensive medicinal chemistry campaign we discovered IACS-010759, a potent, selective small molecule inhibitor of complex I of the mitochondria electron transport chain that possesses excellent pharmacokinetic (PK) and pharmacologic properties, making it suitable for clinical development. We advanced IACS-010759 through IND studies and have recently initiated Phase I studies in patients with relapsed/refractory acute myeloid leukemia (AML) and advanced solid tumors and lymphomas (NCT02882321 and NCT03291938). In this presentation we will describe the identification of a novel series of Complex I inhibitors and their optimization into the clinical candidate compound IACS-010759. Several challenges were successfully overcome, including the optimization of the pharmacokinetic profile and the identification of inhibitors with minimal activity shift across preclinical species, thus enabling a thorough evaluation of the efficacy and toxicology profile. Aspects of the extensive translational research conducted to elucidate the mechanism of action of IACS-010759 and to position it into the clinic will be discussed, including the compelling pharmacological response observed in multiple PDX models of primary AML, and PDX xenograft models of lymphoma, TNBC, glioblastoma, melanoma and PDAC. The observed response was associated with robust pharmacodynamic read-out as assessed by modulation of oxygen consumption rate (OCR), aspartate and specific transcriptional changes. The presentation will also cover the preclinical development activities which resulted in IACS-010759 advancing into on-going phase 1 evaluation in AML and solid tumors. Citation Format: Maria Emilia Di Francesco, Joseph R. Marszalek, Timothy McAfoos, Christopher L. Carroll, Zhijun Kang, Gang Liu, Jay P. Theroff, Jennifer P. Bardenhager, Madhavi L. Bandi, Jennifer R. Molina, Sonal Gera, Marina Protopopova, Yuting Sun, Mary K. Geck Do, Ningping Feng, Jason P. Gay, Florian Muller, Marina Konopleva, Funda Meric-Bernstam, Carlo Toniatti, Timothy P. Heffernan, Giulio F. Draetta, Philip Jones. Discovery and development of IACS-010759, a novel inhibitor of Complex I currently in phase I studies to exploit oxidative phosphorylation dependency in acute myeloid leukemia and solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1655.

Cotargeting BCL-2 and PI3K Induces BAX-Dependent Mitochondrial Apoptosis in AML Cells.

Inhibitors targeting BCL-2 apoptotic proteins have significant potential for the treatment of acute myeloid leukemia (AML); however, complete responses are observed in only 20% of patients, suggesting that targeting BCL-2 alone is insufficient to yield durable responses. Here, we assessed the efficacy of coadministration of the PI3K/mTOR inhibitor GDC-0980 or the p110β-sparing PI3K inhibitor taselisib with the selective BCL-2 antagonist venetoclax in AML cells. Tetracycline-inducible downregulation of BCL-2 significantly sensitized MV4-11 and MOLM-13 AML cells to PI3K inhibition. Venetoclax/GDC-0980 coadministration induced rapid and pronounced BAX mitochondrial translocation, cytochrome c release, and apoptosis in various AML cell lines in association with AKT/mTOR inactivation and MCL-1 downregulation; ectopic expression of MCL-1 significantly protected cells from this regimen. Combined treatment was also effective against primary AML blasts from 17 patients, including those bearing various genetic abnormalities. Venetoclax/GDC-0980 markedly induced apoptosis in primitive CD34+/38-/123+ AML cell populations but not in normal hematopoietic progenitor CD34+ cells. The regimen was also active against AML cells displaying intrinsic or acquired venetoclax resistance or tumor microenvironment-associated resistance. Either combinatorial treatment markedly reduced AML growth and prolonged survival in a systemic AML xenograft mouse model and diminished AML growth in two patient-derived xenograft models. Venetoclax/GDC-0980 activity was partially diminished in BAK-/- cells and failed to induce apoptosis in BAX-/- and BAX-/-BAK-/- cells, whereas BIM-/- cells were fully sensitive. Similar results were observed with venetoclax alone in in vitro and in vivo systemic xenograft models. Collectively, these studies demonstrate that venetoclax/GDC-0980 exhibits potent anti-AML activity primarily through BAX and, to a lesser extent, BAK. These findings argue that dual BCL-2 and PI3K inhibition warrants further evaluation in AML.Significance: Combined treatment with clinically relevant PI3K and BCL-2 inhibitors may prove effective in the treatment of acute myeloid leukemia. Cancer Res; 78(11); 3075-86. ©2018 AACR.

Diagnostic and Prognostic Utility of Fluorescence In situ Hybridization (FISH) Analysis in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a hematologic neoplasia consisting of incompletely differentiated hematopoietic cells of the myeloid lineage that proliferate in the bone marrow, blood, and/or other tissues. Clinical implementation of fluorescence in situ hybridization (FISH) in cytogenetic laboratories allows for high-resolution analysis of recurrent structural chromosomal rearrangements specific to AML, especially in AML with normal karyotypes, which comprises approximately 33-50% of AML-positive specimens. Here, we review the use of several FISH probe strategies in the diagnosis of AML. We also review the standards and guidelines currently in place for use by clinical cytogenetic laboratories in the evaluation of AML. Updated standards and guidelines from the WHO, ACMG, and NCCN have further defined clinically significant, recurring cytogenetic anomalies in AML that are detectable by FISH. FISH continues to be a powerful technique in the diagnosis of AML, with higher resolution than conventional cytogenetic analysis, rapid turnaround time, and a considerable diagnostic and prognostic utility.

APG-1252-12A induces mitochondria-dependent apoptosis through inhibiting the antiapoptotic proteins Bcl-2/Bcl-xl in HL-60 cells.

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. Despite improved remission rates, current treatment regimens for AML are often associated with a very poor prognosis and adverse effects, necessitating more effective and safer agents. B-cell leukemia/lymphoma2 (Bcl-2) family proteins regulate apoptotic pathway that can be targeted with small molecule inhibitors. APG-1252-12A is a Bcl-2 homology (BH)-3 mimetic that specifically binds to Bcl-2 and Bcl-xl, which has shown efficacy in some Bcl-2 dependent hematological cancers. In this study, we investigated whether APG-1252-12A inhibits the growth of five leukemia cell lines in a concentration- or time-dependent manner by MTS assay. Following treatment of AML cell line HL-60 with this compound, cell apoptosis was detected using flow cytometry and nuclear condensation was observed after Hoechst33258 dye. Immunoblotting for cytochromec, cleaved caspase-3 and PARP-1 cleavage was used to demonstrate the mechanism of inducing mitochondria-dependent apoptosis by APG-1252-12A. Our findings showed that this new compound inhibited cell proliferation in five leukemia cell lines and induced apoptotic death. There was a link between the level of Bcl-2 protein and IC50. APG-1252-12A targeted mitochondria and induced caspase-dependent apoptosis by inducing the HL-60 cell cytochromec released, PARP cleavage and caspase activation. These data suggested that APG-1252-12A is a candidate drug for the invivo analysis and clinical evaluation in AML.

Minimal Residual Disease in Acute Myeloid Leukemia: Still a Work in Progress?

Minimal residual disease evaluation refers to a series of molecular and immunophenotypical techniques aimed at detecting submicroscopic disease after therapy. As such, its application in acute myeloid leukemia has greatly increased our ability to quantify treatment response, and to determine the chemosensitivity of the disease, as the final product of the drug schedule, dose intensity, biodistribution, and the pharmakogenetic profile of the patient. There is now consistent evidence for the prognostic power of minimal residual disease evaluation in acute myeloid leukemia, which is complementary to the baseline prognostic assessment of the disease. The focus for its use is therefore shifting to individualize treatment based on a deeper evaluation of chemosensitivity and residual tumor burden. In this review, we will summarize the results of the major clinical studies evaluating minimal residual disease in acute myeloid leukemia in adults in recent years and address the technical and practical issues still hampering the spread of these techniques outside controlled clinical trials. We will also briefly speculate on future developments and offer our point of view, and a word of caution, on the present use of minimal residual disease measurements in “real-life” practice. Still, as final standardization and diffusion of the methods are sorted out, we believe that minimal residual disease will soon become the new standard for evaluating response in the treatment of acute myeloid leukemia.

The clinical and prognostic significance of acute myeloid leukemia with FLT3-ITD

目的探讨FLT3-ITD突变阳性急性髓系白血病（AML）的临床特征和预后因素，为FLT3-ITD突变阳性AML患者的预后评估提供更多证据。方法收集98例FLT3-ITD突变阳性AML初诊患者的临床资料，对其临床特征与预后的相关性进行统计学分析。结果98例FLT3-ITD突变阳性AML患者初诊时中位WBC 58.2（0.3~461.8）×109/L，外周血原始细胞绝对计数中位数42.2(0～397.1）×109/L。71例细胞遗传学中高危组患者1个疗程完全缓解（CR）率为60.6%，原发耐药率为26.8%。单因素分析结果显示外周血原始细胞绝对计数低是影响患者1个疗程CR的良好预后因素（P=0.009）。多因素分析结果显示，1个疗程达CR（HR=0.395，95%CI 0.183~0.850，P=0.001）及第1次CR期行异基因造血干细胞移植（HR=0.180，95%CI 0.043~0.752，P=0.018）是影响患者无复发生存的良好预后因素，1个疗程达CR（HR=0.251，95%CI 0.121~0.523，P<0.001）及外周血原始细胞绝对计数低（HR=0.219, 95%CI 0.088~0.545，P=0.003）是影响患者总生存的良好预后因素。结论外周血原始细胞计数低的FLT3-ITD突变阳性AML患者预后相对良好，1个疗程达CR和第1次CR期行异基因造血干细胞移植是改善FLT3-ITD突变阳性AML患者预后的重要治疗策略。

Cytogenetics in the management of acute myeloid leukemia: an update by the Groupe francophone de cytogénétique hématologique (GFCH).

The karyotype is critical for the evaluation of acute myeloid leukemia (AML) at diagnosis. Cytogenetic abnormalities detected in AML are one of the most powerful independent prognostic factors. It impacts on the choice of treatment in clinical trials. All chromosomes can be targeted, common chromosomal abnormalities are recurrent and may be associated with a cytological well-defined type. In 40% of the cases, the karyotype is normal and must be associated with molecular biology studies that can refine the prognosis. The usefulness of the karyotype is more limited during the follow-up of the patient due to its limited sensitivity, but it is still useful in the clinical management of relapse. Since 2001, the WHO (World Health Organization) classification of hematological malignancies integrates cytogenetic data in the classification of AML. Karyotype is therefore mandatory in the diagnosis of AML.

Acute Myeloid Leukemia Genetics: Risk Stratification and Implications for Therapy.

Acute myeloid leukemia is a category of diseases with a common aggressive clinical presentation but with a prognosis and management that is dependent upon the underlying genetic characteristics of the neoplasm. The purpose of this brief review is to update the practicing pathologist on the current standard of care in the genetic evaluation of acute myeloid leukemia and to highlight future directions in the classification, genetic assessment, and management of these devastating diseases.

Abstract 90: Development of a systemic Kasumi-3 acute myeloid leukemia model in NSG mice

Abstract In vivo models that reproduce human disease are needed for the evaluation of acute myeloid leukemia (AML) disease progression and the development of effective treatments for the disease. The NSG mouse strain is used to model human AML due to the absence of mature B and T lymphocytes and lack of functional NK cells. Successful systemic engraftment of human AML cells in these mice may provide similar disease manifestation observed in patient disease, thus allowing evaluation of therapeutic candidates. The Kasumi-3 cell line from ATCC was established from the blast cells of a myeloperoxidase-negative acute leukemia patient and expresses CD7, CD4, CD13, CD33, CD34, HLA-DR and c-Kit cell surface markers which are compatible with acute myelocytic leukemia, subtype M0 (AML-M0). The prognosis of patients with AML-M0 is poor in comparison to other classifications of AML due to the association of these leukemia cells as being extremely immature and either undifferentiated or minimally differentiated. We have developed a systemic Kasumi-3 human AML model, characterizing tumor cell engraftment over time, following intravenous implantation of Kasumi-3 AML cells in NSG mice. Kasumi-3 cells were implanted at either 1e6 or 10e6 cells per NSG mouse and tumor burden throughout disease progression was assessed by monitoring the engraftment of these cells in the peripheral blood, bone marrow and spleen by FACS analysis. The engraftment of huCD45+ cells was used as a marker for determining the percentage of human tumor cell burden in the mice. Results indicated that within 28 days post intravenous implantation of Kasumi-3 cells at either concentration, huCD45+ cells were present in the peripheral circulation, bone marrow and spleens of NSG mice, and the tumor cell engraftment percentages strongly correlated with the number of implanted Kasumi-3 AML cells. Both the 1e6 and 10e6 cell implant concentrations exhibited unidirectional changes in the percentage of huCD45+ cells engrafting in the peripheral blood, bone marrow, and spleen at all time points throughout the experiment. After analyzing the percentages of human tumor cell engraftment in the NSG mice, the 10e6 Kasumi-3 cell implant concentration showed tumor cell engraftment of 35% in the blood, 67% in the bone marrow and 16% in the spleen on Day 28 and provided the most appropriate environment for the in vivo onset and evaluation of AML tumor burden. The 1e6 Kasumi-3 concentration had a lower percentage of systemic tumor cell engraftment at Day 28 when compared to the percentage of huCD45+ cell engraftment with 10e6 cells. The higher implant concentration showed established tumor burden in the peripheral blood and spleen 14 days sooner than the 1e6 cell dose, which would allow for the observation of efficacy and treatment effects in this model sooner than the 1e6 cell concentration. The establishment of this human AML model in NSG mice can serve as an in vivo tool for the evaluation of putative therapeutics for AML. Citation Format: Diana Chin, Christine Pietsch, Francis McCabe, Susan Chippari, Elizabeth Kaiser, Rebecca Hanson, Mariusz Lubomirski. Development of a systemic Kasumi-3 acute myeloid leukemia model in NSG mice. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 90. doi:10.1158/1538-7445.AM2014-90

ASP2215, a novel FLT3/AXL inhibitor: Preclinical evaluation in acute myeloid leukemia (AML).

7070 Background: Activating mutations in FLT3 receptor tyrosine kinase, characterized by internal tandem duplication (ITD) and tyrosine kinase domain point mutations near position D835, have been i...

Karyotypic Complexity In Acute Myeloid Leukemia In The Context Of Adverse Prognosis

IntroductionCytogenetic analysis is a mandatory component in the diagnostic evaluation of acute myeloid leukemia (AML) providing information regarding the biology of the disease including response or resistance to therapy. One of the cytogenetic markers which reflect an adverse outcome in conventional chemotherapy regimens is the complex aberrant karyotype consisting of multiple unrelated cytogenetic abnormalities. In AML two definitions have been established which differ in the perception of unbalanced aberrations as well as the number of single aberrations. The ELN classification scheme adopts three unrelated abnormalities while the UK MRC recently recommended four abnormalities as the most informative cut-off of complexity in the context of an adverse prognosis. The aim of this work was to study the best cut-off defining complexity (3 vs. 4) in AML with other cytogenetic high-risk markers. MethodsThe databases of three clinical multicentric, randomized, and prospective SAL trials (NCT 00180115, 00180102, and 00180167) were analyzed for AML patients with multiple cytogenetic aberrations as well as normal karyotypes (control group). Unbalanced abnormalities were counted as two aberrations according to the recommendations of the MRC (i.e. a single unbalanced translocation leading to gain and loss of chromosomal material as two unique abnormalities). The following single aberrations associated with an adverse prognosis according to ELN as well as UK MRC recommendations were included: inv(3), t(3;3), abn(3q), -5, del(5q), t(5q), t(6;9), -7, add(7q)/del(7q), t(11;v)(q23;v) (except t(9;11)), and abnl(17p). ResultsComplete data were analyzed from 2056 patients: normal karyotype (NK) n=1590, three aberrations (K3) n=65, ≥ four aberrations (K4) n=355, t(8;21)/inv(16)/t(16;16) and at least two additional aberrations n=46. All four groups differed significantly in 5–year overall survival (OS): 35% [95% CI 32–37], 19% [95% CI 9–29], 7% [95% CI 4–10], 67% [95% CI 53–81], respectively, p≤0.001. The K4 group had a significant inferior 5–year OS as compared to the K3 group, 19% [95% CI 9–29] and 7% [95% CI 4–10], p≤0.001. HSCT was performed in first remission in 25% of patients with K3 (n=16) and 17% of patients with K4 (n=59) (p=n.s.). As demonstrated earlier, multiple aberrations additional to the good risk anomalies (t(8;21), inv(16), or t(16;16)) did not impact on the favourable prognosis of the respective group. In the K3 and K4 groups single adverse risk abnormalities were found in 55% (abnl(17p) 12%) and 83% (abnl(17p) 37%) in these patients, respectively. A hyperdiploid karyotype (HDK) with gains of whole chromosomes without any structural aberration or monosomy was present in 14% of K3 and 3% of K4-patients. Interestingly, HDK with three trisomies as well as ≥ four trisomies led to a survival similar to K4 patients without HDK. Therefore, the K3 group lost its inferior survival as compared to NK when patients with adverse risk, which induce a worse prognosis per se, as well as HDK were excluded (5y–OS: 29% [9–44] vs. 35%, [95% CI 32–37], p=n.s.). HDK patients or patients with additional single adverse risk abnormalities had a worse survival compared to NK (5y–OS: 11%, [95% CI 0–32], p=0.012; and 15%, [95% CI 3–28], p=0.004 vs. 35%, [95% CI 32–37], respectively). In contrast, when comparing the K4 group after exclusion of adverse risk and HDK patients to NK, the K4 group remained its inferior OS as compared to NK, p<0.001. ConclusionsHence, our investigation confirms and therefore favors the ≥4 cut-off of complexity in the context of an adverse prognosis as proposed by the MRC with the exception of HDK patients. HDK patients should be considered as high-risk independent of the level of complexity. Whether K3 patients without single adverse risk abnormalities and HDK should be treated as intermediate risk, as suggested by our results, needs to be investigated prospectively in clinical trials. Disclosures:Platzbecker:Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding.

PCN79 Pharmacoeconomic Evaluation of Acute Myeloid Leukemia and MDS Syndromes (Intermediate and High Risk) Treatment With Azacitidine in the Russian Federation

PCN79 Pharmacoeconomic Evaluation of Acute Myeloid Leukemia and MDS Syndromes (Intermediate and High Risk) Treatment With Azacitidine in the Russian Federation

Relationship Between Cleaved L-Selectin Levels and the Outcome of Acute Myeloid Leukemia

High plasma levels of the shed form of L-selectin (sL-selectin) are frequently detectable in acute myeloid leukemia (AML). sL-selectin can inhibit blast cell adhesion to vascular endothelium and may thereby influence the phenotype of AML. In this study, we have investigated the relationship between sL-selectin levels and clinical presentation or disease outcome in 100 patients with AML. Fifty-eight patients were found to have sL-selectin levels >/=3.12 microgram/mL (>/=3 SD above the mean of healthy controls: "increased"). Patients with extramedullary disease such as lymphadenopathies, splenomegaly, hepatomegaly, and/or muco-cutaneous infiltration had significantly increased sL-selectin levels (P < .001). sL-selectin levels were significantly heterogeneous in the French-American-British subtypes (P = .0003). Patients with "normal" sL-selectin levels had higher probability of achieving complete remission (CR) than with "increased" levels: 81% versus 64%, respectively (P = .06). When adjusting for clinically relevant covariates predictive for CR (sex, age, Auer rods), "normal" sL-selectin levels were significantly associated with CR (odds ratio, 3.08; 95% confidence interval [CI], 1.10 to 8.58; P = .03). Moreover, patients with "increased" sL-selectin levels (>/=3.12 microgram/mL) had shorter event-free survival (EFS) (median 7.3 v 12 months, P = .008) and overall survival (median 1 v 2.05 years, P = .03) than patients with sL-selectin <3.12 microgram/mL. Multivariate statistical analysis (adjusted for age and presence of Auer rods) indicated that sL-selectin was an independent prognostic factor for EFS (hazard ratio [HR], 1.96; 95% CI, 1.21 to 3.17, P = .006) and overall survival (HR, 1.80; 95% CI, 1.09 to 2.98; P = .02). Thus, plasma sL-selectin may be a useful prognostic marker in the evaluation of AML at diagnosis.

Relationship Between Cleaved L-Selectin Levels and the Outcome of Acute Myeloid Leukemia

High plasma levels of the shed form of L-selectin (sL-selectin) are frequently detectable in acute myeloid leukemia (AML). sL-selectin can inhibit blast cell adhesion to vascular endothelium and may thereby influence the phenotype of AML. In this study, we have investigated the relationship between sL-selectin levels and clinical presentation or disease outcome in 100 patients with AML. Fifty-eight patients were found to have sL-selectin levels ≥3.12 μg/mL (≥3 SD above the mean of healthy controls: “increased”). Patients with extramedullary disease such as lymphadenopathies, splenomegaly, hepatomegaly, and/or muco-cutaneous infiltration had significantly increased sL-selectin levels (P &lt; .001). sL-selectin levels were significantly heterogeneous in the French-American-British subtypes (P = .0003). Patients with “normal” sL-selectin levels had higher probability of achieving complete remission (CR) than with “increased” levels: 81% versus 64%, respectively (P = .06). When adjusting for clinically relevant covariates predictive for CR (sex, age, Auer rods), “normal” sL-selectin levels were significantly associated with CR (odds ratio, 3.08; 95% confidence interval [CI], 1.10 to 8.58;P = .03). Moreover, patients with “increased” sL-selectin levels (≥3.12 μg/mL) had shorter event-free survival (EFS) (median 7.3 v 12 months, P = .008) and overall survival (median 1 v 2.05 years, P = .03) than patients with sL-selectin &lt;3.12 μg/mL. Multivariate statistical analysis (adjusted for age and presence of Auer rods) indicated that sL-selectin was an independent prognostic factor for EFS (hazard ratio [HR], 1.96; 95% CI, 1.21 to 3.17, P = .006) and overall survival (HR, 1.80; 95% CI, 1.09 to 2.98; P = .02). Thus, plasma sL-selectin may be a useful prognostic marker in the evaluation of AML at diagnosis.© 1998 by The American Society of Hematology.

Gene Immunotherapy in Murine Acute Myeloid Leukemia: Granulocyte-Macrophage Colony-Stimulating Factor Tumor Cell Vaccines Elicit More Potent Antitumor Immunity Compared With B7 Family and Other Cytokine Vaccines

AbstractIn an attempt to explore novel treatment modalities in acute myeloid leukemia (AML), we studied the role of costimulatory and cytokine gene immunotherapy in murine AML. We have previously shown that leukemic mice can be cured with CD80 transfected leukemic cells (B7.1-AML vaccine) administered early in the course of the disease and that the failure B7.1-AML vaccines administered late cannot be attributed to immunosuppression induced by tumor growth. CD8+ T cells, which are necessary for tumor rejection, are activated rather than suppressed during the first half of the leukemic course in nonvaccinated mice. In this report, we question whether CD86 (B7.2) or the cytokines granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-4 (IL-4), or tumor necrosis factor-α (TNF-α) can improve the vaccination potential of AML cells. The choice of cytokines was based on their combined and alone as well ability to direct the differentiation of CD34+ cells into potent antigen-presenting dendritic cells in vitro. Our studies show that (1) mice vaccinated with a leukemogenic number of AML cells engineered to express B7.2 (B7.2-AML) or to secrete GM-CSF, IL-4, or TNF-α (GM-, IL-4–, TNF-α–AML) do not develop leukemia; (2) GM-AML cells are tumorigenic in sublethally irradiated SJL/J mice but not in Swiss nu/nu mice, indicating that killing of tumor cells is not T-cell–dependent; (3) vaccines with irradiated GM-AML, but not B7.2-, IL-4–, or TNF-α–AML cells, can elicit leukemia-specific protective and therapeutic immunity; and (4) in head-to-head comparison experiments, vaccination with irradiated GM-AML is more potent than B7.1-AML, curing 80% and providing 20% prolonged survival of the leukemic mice at week 2, as opposed to cures only up to 1 week with B7.1-AML vaccines. These preclinical data emphasize that GM-CSF gene immunotherapy deserves clinical evaluation in AML.

Gene Immunotherapy in Murine Acute Myeloid Leukemia: Granulocyte-Macrophage Colony-Stimulating Factor Tumor Cell Vaccines Elicit More Potent Antitumor Immunity Compared With B7 Family and Other Cytokine Vaccines

In an attempt to explore novel treatment modalities in acute myeloid leukemia (AML), we studied the role of costimulatory and cytokine gene immunotherapy in murine AML. We have previously shown that leukemic mice can be cured with CD80 transfected leukemic cells (B7.1-AML vaccine) administered early in the course of the disease and that the failure B7.1-AML vaccines administered late cannot be attributed to immunosuppression induced by tumor growth. CD8+ T cells, which are necessary for tumor rejection, are activated rather than suppressed during the first half of the leukemic course in nonvaccinated mice. In this report, we question whether CD86 (B7.2) or the cytokines granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-4 (IL-4), or tumor necrosis factor-α (TNF-α) can improve the vaccination potential of AML cells. The choice of cytokines was based on their combined and alone as well ability to direct the differentiation of CD34+ cells into potent antigen-presenting dendritic cells in vitro. Our studies show that (1) mice vaccinated with a leukemogenic number of AML cells engineered to express B7.2 (B7.2-AML) or to secrete GM-CSF, IL-4, or TNF-α (GM-, IL-4–, TNF-α–AML) do not develop leukemia; (2) GM-AML cells are tumorigenic in sublethally irradiated SJL/J mice but not in Swiss nu/nu mice, indicating that killing of tumor cells is not T-cell–dependent; (3) vaccines with irradiated GM-AML, but not B7.2-, IL-4–, or TNF-α–AML cells, can elicit leukemia-specific protective and therapeutic immunity; and (4) in head-to-head comparison experiments, vaccination with irradiated GM-AML is more potent than B7.1-AML, curing 80% and providing 20% prolonged survival of the leukemic mice at week 2, as opposed to cures only up to 1 week with B7.1-AML vaccines. These preclinical data emphasize that GM-CSF gene immunotherapy deserves clinical evaluation in AML.

Cell-cycle prognostic value in adult acute myeloid leukemia. The choice of the best variables

Flow cytometry with simultaneous analysis of DNA and protein content allows a most exhaustive study of cell-cycle for the prognostic evaluation of acute myeloid leukemia (AML). Sixty-seven cases of AML were studied before any form of chemotherapy had been undertaken. We determined the following cell-cycle variables: S, S + G2 + M, low protein content fraction (LPC-fraction) and high protein content fraction of G1 (HPC-G1). Patients were stratified according to age: S and S+G2+M phases were higher for patients over 50 who did not achieve a complete remission. LPC-fraction was significantly lower for patients older than 50 who did not achieve a complete remission not only compared to the complete remission group of patients over 50, but also compared to the younger non responder group. The duration of survival was significantly longer when LPC-fraction was higher than 26% and HPC-G1 lower than 70%. Length of survival was also better when S+G2+M was longer than 5.75%. Analysis of the therapy failure showed that S + G2 + M and LPC-fraction were significantly different between the complete remission group and the group of patients dying in aplasia. Overall, patients older than 50 with a proliferative leukemia had a worse prognosis.