Outcome In Adult Acute Myeloid Leukemia Research Articles

The Diversity of FLT3-ITD and the Prognostic Impact in Adult Acute Myeloid Leukemia

Introduction FLT3 internal tandem duplication (ITD) is commonly detected in patients with acute myeloid leukemia (AML) and is known to confer poor prognosis. It has different insertion numbers, mutation burden, insertion sizes, insertion sites and insertion nucleotide sequences, showing complex diversity. However, the guideline of AML did not sufficiently consider the impact of the diversity of FLT3-ITD on treatment responses, and previous studies have not been consistent with the impact of FLT3-ITD diversity on clinical prognosis. In this study we examined the diversity of FLT3-ITD and correlated these parameters with clinical outcome in adult AML. In addition, we revealed the correlation between FLT3-ITD and drug resistance through evolutionary trajectories in primary resistant patients. Methods We included adult patients from 2016-2021 at Henan Cancer Hospital with newly diagnosed adult AML. next generation sequencing (NGS) was performed for all patients at diagnosis. The FLT3-ITD was also detected using conventional methods based on PCR, with a cut-off of 3% for positivity. The comparative analysis of NGS and PCR was done to validate the diversity of FLT3-ITD. Whole genome sequencing (WGS) data for multiple time points were used to analyze clonal evolution. Data were collected by chart review. The chi-squared or Fisher's exact test, Mann-Whitney U test, log-rank and Cox regression analyses were performed. Results Among 406 newly diagnosed adult AML patients, 24.4% (99/406) patients were detected with FLT3-ITD. The FLT3-ITD diversity was validated by NGS and PCR data from 90 FLT3-ITD positive patients. 61.1% (55/90) patients had single FLT3-ITD (sFLT3-ITD) (31M/24F, median age 46 at diagnosis, range 18-64), and 38.9% (35/90) patients carried multiple FLT3-ITDs (mFLT3-ITD) at the same time (23M/12F, median age 47 at diagnosis, range 19-64). A total of 161 FLT3-ITDs were detected, with a median mutation burden of 21.51% (0.71-93.21%) and a median insertion length of 36bp (9-189 bp). 80.20% of FLT3-ITD insertions were in the near-membrane region, and 45.54% of FLT3-ITD insertions contained exogenous nucleic acid sequences. Patients with mFLT3-ITD had a significantly lower CR rate than those with sFLT3-ITD (25.7% vs 60.0%, p=0.001), while the CR rate of patients with sFLT3-ITD was similar to patients without FLT3-ITD (60.0% vs 58.6%, p=0.521). In the setting of NPM1, the CR rate of patients with sFLT3-ITD+NPM1 mut improved significantly when compared to patients with sFLT3-ITD+NPM1 wild (76.9% vs 44.8%, p=0.015). Unfortunately, the state of NPM1 had no impact on the CR rate of patients with mFLT3-ITD. After a median follow-up of 38.9 months, the median overall survival (OS) has not been reached for patients with a single FLT3-ITD, and the median OS for patients with multiple FLT3-ITDs was only 12.4 months (95 CI, 3.8 to 20.9) ( p=0.028). Multivariate analysis confirmed its prognostic significance on CR rate (HR 2.13, 95% CI, 1.38-4.20, p=0.020) but not on OS. The mutation burden, insertion sizes, insertion sites and insertion nucleotide sequences of FLT3-ITD had no significant impact on the CR rate or OS. To explore the clonal architecture of mFLT3-ITD, single cell DNA sequencing on one patient showed that respective FLT3-ITD variants were detected in completely separated cell populations. This suggested that mFLT3-ITD independently occurred in different subclone. WGS data of persistent primary resistant patients at multiple time points were used to analyze the evolutionary trajectory under chemotherapy. We observed complete separation of evolving trajectory of different FLT3-ITD variants over the course of chemo-treatment. Importantly, FLT3-ITD subclone of diagnosis evolved into the dominant clone at resistance. Conclusion In summary, by exploring the impact of the FLT3-ITD diversity on clinical prognosis and the evolutionary trajectory of mFLT3-ITD, the FLT3-ITD number may be a biomarker to refine the risk stratification and further identify adverse populations among FLT3-ITD positive AML patients.

DNMT3A Mutants Are Enriched in NPMc+ AML and Associated with Adverse Outcome in Childhood AML

Background: Somatic mutations in the DNA methyltransferase 3 alphagene (DNMT3A) are common in adult acute myeloid leukemia (AML), but are rare events in childhood AML (Ho, Ped Blood Cancer, 2011). Missense mutations occur most frequently in the catalytic domain at R882, resulting in loss of enzyme methylation activity and the ability of the enzyme to bind DNA. DNMT3Amutations are associated with adverse outcome in adults, while their impact is understudied in childhood AML. Our objective was to identify the prevalence of DNMT3A -mutated AML across the childhood age spectrum utilizing a large cohort of patients enrolled on pediatric trials and compare findings with adult cohorts. Methods: Pediatric patients treated on two consecutive COG trials with publicly available data were included (n=1607). Mutational profiling was performed by whole genome and transcriptome sequencing methods. Prevalence of DNMT3Amutations, co-occurring mutations, and outcomes (5-year event-free [EFS] and 5-year overall survival [OS]) were analyzed. Results: The prevalence of DNMT3Amutations amongst the entire childhood cohort was 1.2% (n=20/1607). DNMT3A mutations were absent in children <10 years with increased incidence up to 2.6% in patients >10yrs of age. All variants were missense, with the exception of one nonsense mutation and alterations at the 882 residue were the most common (70%). Most importantly, all but 4 DNMT3A mutations occurred in patients with NPM1 mutations (NPMc+; 80%). Conversely, DNMT3A mutations were seen in 9% of all NPM positive patients, demonstrating unique enrichment of this mutation within the NPM1 mutant cohort. Further, R882 mutations were seen in all but a single patient with the dual NPM/DNMT3A variant. It is notable that 11 patients harbored additional FLT3-ITD mutations (triple positive), which we have previously reported to be associated with adverse outcome in adults. In addition to mutations in NPM1 and FLT3, co-occurring variants with DNMT3A were also found in PTPN11 (35%), and WT1, IDH1/2 and MYC each at 10% frequency (Fig.A). Given the recent report of association of NPM1 mutation genotype and association of Type D mutation with adverse outcome (Pigazzi, ASH 2023), we evaluated NPM1 mutation genotype in those with cooperating DNMT3A mutation which demonstrated lack of association of DNMT3A mutations and Type D NPM1 mutations. Current risk classification in COG pediatric AML trials treat NPMc+ patients as favorable risk. Given the prevalence of DNMT3A mutations in NPMc+ patients we inquired whether DNMT3A mutations might modify outcome in this population. The 5 yr EFS estimates for NPMc+; patients with and without DNMT3A was 26.8% vs. 74.8% (p<0.0001; Fig.B) with a corresponding OS estimate at 5yrs of 60.3% vs. 82.2% (p=0.0169). We further concluded that presence or absence of FLT3-ITD does not impact the adverse outcome with similar 5 yr EFS for those with dual NPM1/DNMT3A or triple NPM1/DNMT3A/FLT3-ITD positive AML(20.0% vs. 30.3%respectively). These data are consistent with the adult DNMT3A data previously presented last year (Torabi; ASH 2022; abstract #306) regarding clinical implications of DNMT3A mutation in the setting of cooperating NPM1 mutation. Conclusion: Mutational profiling of children with AML identified DNMT3A mutations in adolescents and young adults and is enriched in those with NPMc+ mutations. As NPMc+ patients are considered to be favorable risk, knowledge of DNMT3A mutations would provide additional information for more precise risk stratification in childhood AML. Children with de novo AML and dual DNMT3A/NPM1 mutations remain at high risk of relapse and adverse outcome regardless of FLT3-ITD status.

PB1801: CHROMOSOMAL ABNORMALITIES DURING THE CLINICAL COURSE OF ADULT ACUTE MYELOID LEUKEMIA

Background: Using conventional cytogenetics, an abnormal karyotype can be detected in 60-70% of adult acute myeloid leukemia (AML) patients. Taking into consideration the identified cytogenetic abnormalities AML patients are currently classified into three risk groups: favorable, intermediate and adverse. These genetic abnormalities are the most important factors in determining response to chemotherapy as well as outcome in AML. Aims: Aim of this study was to detect the diagnostic and prognostic significance of chromosomal abnormalities in leukemic cells at different phases of AML. Methods: Cytogenetic investigations of bone marrow and/or peripheral blood cells from 140 adult patients were performed during clinical evolution of AML: in newly diagnosed patients, in remission and at relapse. The methods of conventional cytogenetics (GTG) and fluorescence in situ hybridization (FISH) were used. Cytogenetic methods were performed using standard techniques and karyotypes were described according to the International System for Human Cytogenetic Nomenclature. Results: Cytogenetic investigations of 140 adult AML patients were performed in newly diagnosed patients, in remission and at relapse. Structural (del(5q), del(7q), rearrangements of 3q, 12p, 17p and 11q23, t(8;21)(q22;q22), t(9;22)(q34;q11), t(15;17)(q22;q21), t(16;16)(p13;q22), inv(16)(p13q22), marker and ring chromosomes, acentric structures and others) and numerical (-5, -7, -Y, +8, monosomal karyotype and others) chromosomal abnormalities in leukemic cells were found. Some genetic abnormalities (BCR/ABL1, PML/RARa, AML1/ETO, CBFβ/MYH11 fusion genes) were detected by molecular genetic methods (FISH). Spectrum of cytogenetic abnormalities had an important diagnostic and prognostic significance. Diagnosis of AML was possible due to the presence of specific genetic markers that can confirm some types of AML (AML with t(8;21)(q22;q22), t(9;22)(q34;q11), t(15;17)(q22;q21), t(16;16)(p13;q22)/inv(16)(p13q22), 3q21q26 rearrangements, BCR/ABL1, PML/RARa, AML1/ETO, CBFβ/MYH11 fusion genes). Taking into consideration the identified cytogenetic abnormalities AML patients were classified by risk groups: the group of patients with adverse cytogenetic markers (3q21q26 rearrangements, -5, -7, t(9;22)(q34;q11), BCR/ABL1 fusion gene, multiple changes (≥3), monosomal karyotype), the intermediate risk group without significant prognostic markers and the group with favorable prognostic factors (t(8;21)(q22;q22), t(15;17)(q22;q21), t(16;16)(p13;q22)/inv(16)(p13q22), AML1/ETO, PML/RARa, CBFβ/MYH11 fusion genes). In remission cytogenetic investigations showed a normal karyotype without cytogenetically visible changes in all patients. Cytogenetic investigations at relapse were performed in 5 of 140 AML cases. Additional/secondary chromosomal aberrations in leukemic cells or new cells clones with multiple structural and numerical changes at relapse was not detected. Summary/Conclusion: Cytogenetic investigations had an important significance for diagnosis, prognosis and selection the optimal treatment strategy of AML. Besides the analysis of chromosome banding patterns it is necessary for patients with AML to apply molecular genetic studies, namely FISH and polymerase chain reaction (PCR). Taking into consideration the identified cytogenetic abnormalities AML patients were classified by risk groups. Presence of the additional/secondary chromosomal aberrations in leukemic cells or new cells clones with multiple structural and numerical changes at AML relapse is the one sign of clonal evolution and progression of disease.

Differential impact of IDH1/2 mutational subclasses on outcome in adult AML: results from a large multicenter study

AbstractMutations of the isocitrate dehydrogenase-1 (IDH1) and IDH2 genes are among the most frequent alterations in acute myeloid leukemia (AML) and can be found in ∼20% of patients at diagnosis. Among 4930 patients (median age, 56 years; interquartile range, 45-66) with newly diagnosed, intensively treated AML, we identified IDH1 mutations in 423 (8.6%) and IDH2 mutations in 575 (11.7%). Overall, there were no differences in response rates or survival for patients with mutations in IDH1 or IDH2 compared with patients without mutated IDH1/2. However, distinct clinical and comutational phenotypes of the most common subtypes of IDH1/2 mutations could be associated with differences in outcome. IDH1-R132C was associated with increased age, lower white blood cell (WBC) count, less frequent comutation of NPM1 and FLT3 internal tandem mutation (ITD) as well as with lower rate of complete remission and a trend toward reduced overall survival (OS) compared with other IDH1 mutation variants and wild-type (WT) IDH1/2. In our analysis, IDH2-R172K was associated with significantly lower WBC count, more karyotype abnormalities, and less frequent comutations of NPM1 and/or FLT3-ITD. Among patients within the European LeukemiaNet 2017 intermediate- and adverse-risk groups, relapse-free survival and OS were significantly better for those with IDH2-R172K compared with WT IDH, providing evidence that AML with IDH2-R172K could be a distinct entity with a specific comutation pattern and favorable outcome. In summary, the presented data from a large cohort of patients with IDH1/2 mutated AML indicate novel and clinically relevant findings for the most common IDH mutation subtypes.

Postremission Therapy with Repeated Courses of HD-Arac, Idarubicin and Limited Autologous Stem Cell Support Achieves a Very Good Long-Term Outcome in ELN Favourable and Intermediate-Risk AML Except in NPM-Mutated Patients Where Relapse May Occur Even after Five Years

Introduction: Postremission treatment in adult acute myeloid leukemia (AML) is mandatory to improve long-term remission duration. Allogeneic stem-cell transplantation (allo-SCT) is considered gold standard in younger patients (pts) with higher risk of relapse, whereas in pts categorized as standard-risk (SR) AML the optimal treatment remains an open issue. High-dose cytarabine (HD-ARAC) is considered the backbone of postremission treatment in SR AML. The optimal dose and schedule, and the clinical benefit of additional chemotherapeutic agents remain controversial (Schaich, 2011- Lowenberg, 2011- Lowenberg, 2013) as well as the relative efficacy of HD-ARAC in the different cytogenetic and molecular subgroups of SR AML. We analyzed the very long term outcome of consecutive unselected AML pts treated according to AML 00 NILG protocol (Bassan, Blood, 2003: 102; 11) with three repetitive HD-ARAC-based cycles, associated with idarubicin, followed by limited peripheral blood stem cell (PBSC) support, in order to reduce toxicities.Methods: We evaluated 263 consecutive AML pts, diagnosed at our Institution, from January 2001 to March 2016 (median age 52 years - range 15-65). The treatment plan included induction with ICE (Idarubicin-Cytarabine-Etoposide) followed by IC consolidation or HD-ARAC/HD-idarubicin (SPLIT therapy) in refractory cases. ARAC 1g/mq bd for 4 days (A8) was given to CR pts, to collect 3-6x10^6 CD34/kg in 3 aliquots. Patients with ELN favorable or intermediate risk AML, considered SR AML, received 3 cycles of HD-ARAC (2g/mq bd for 5 days) plus idarubicin (8mg/mq for 2 days) with PBSC reinfusion (1-2x10^6 CD34/Kg) (A20). The pts with insufficient CD34 cells yield, received 2 courses HD-ARAC (1g/mq bd for 5 days) plus idarubicin (10mg/mq day 1) (A10). The cumulative dose of ARAC and idarubicin given according to A20 protocol were 69,4 g/mq and 162 mg/mq, respectively.Results: Among 263 pts, 142 (54%) pts were considered SR and 116 (44.1%) HR. Only 5 pts were lacking molecular or cytogenetic information (1.9%) to allow ELN risk classification. Accordingly, 65 pts (25.2%) were favorable [35.4% core binding factor (CBF) positive, 9.2% CEPBA mutated and 55.4% NPM mutated], 87 (33.7%) Intermediate-I, 45 (17.4%) Intermediate II and 61 (23.7%) adverse risk. CR rate after ICE treatment was 77.6% (204/263), 95.8% in SR and 56% in HR pts and after ICE+SPLIT it was 88.2% (232/263); early or aplastic death was 6%. A8 course was administered in 218 pts, of whom 179 were successfully mobilized (82.1%). Among 136 SR pts, 127 were received HD-ARAC (A20 or A10), 4 allo-SCT for early relapse, 3 pts did not proceed to A20 because of prolonged cytopenia and 2 are ongoing. Hematological toxicity was acceptable. ANC recovered at a median of 10 days after CD34+ cells reinfusion. Two death in CR occurred within 100 days after A20 therapy (1.6%). After a median follow-up of 53.3 months (range 1-172), the median survival of SR AML patients was 118.9 months, the DFS and OS at 5 y were 51+/-4.8% and 56.5+/-4.7%, and at 10 y 43.3+/-5.9% and 49.6+/-5.7%, respectively. According to ELN risk, the OS at 5 y and 10 y was 78.3+/-6% and 68+/-8.7% in favorable (median OS not reached), 52.3+/-8% and 46+/-9.4% in Intermediate-I (median OS 118.8 months), and 42+10% and 33.6+/-10.9% in Intermediate-II (median OS 33.1 months) (p0.0034) (Figure1). According to molecular characteristics, the OS at 5-y was 100% in CEBPA-mutated, 77+/-9% (+/-SE) in CBF-mutated and 71+/-11% in NPM-mutated subgroups, respectively (Figure 2). In NPM-mutated pts it was 56+/-14% if FLT3 was mutated and 75+/-10% if not. At 8-y OS was not evaluable in CEBPA-mutated, it remained 77+/-9% in CBF mutated but dropped to 47+/-15% in NPM-mutated pts due to late relapses (28%), which occurred in pts without FLT3. The median time to relapse in NPM pts was 17 m, the latest relapse occurred after 97 months.Conclusion: A postremission program with repeated courses of HD-ARAC associated to idarubicin and limited autologous CD34+ cells support was feasible, well tolerated and very effective, also long-term, in pts with ELN favourable or intermediate risk AML. The late relapse tendency of NPM-mutated AML is puzzling and should be considered by innovative programs aimed at improving these results. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Expression of thioredoxin-1 (TXN) and its relation with oxidative DNA damage and treatment outcome in adult AML and ALL: A comparative study

Objective: Thioredoxin-1 (TXN) is a key element in the elimination of reactive oxygen species as well as activation of tumor suppressor genes and DNA repair enzymes. Several studies showed that TXN was over expressed in solid tumors and this was correlated to poorer prognosis. However, TXN expression has been insufficiently studied, particularly in newly diagnosed adult acute leukemia. Methods: This study was designed to evaluate the gene expression of TXN in acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL) adult patients and to investigate its association with oxidative DNA damage. The expression of TXN was analyzed using quantitative reverse transcriptase-polymerase chain reaction while oxidative DNA damage was evaluated by measuring serum 8-hydroxy-2-deoxyguanosine (8-OHdG) by enzyme-linked immunosorbent assay and strand breaks by the comet assay. Results: We found that TXN was under expressed in both AML and ALL groups (P < 0.001 for both) as compared to the control group. Also TXN expression level was negatively correlated with serum 8-OHdG and tail moment in both AML (P = 0.042 and 0.047, respectively) and ALL (P < 0.001 and P = 0.02, respectively) while it showed no correlation with treatment outcome in either groups. Discussion: This study suggests that TXN expression is hindered in adult acute leukemia which augments oxidative DNA damage and hence mutagenesis. Conclusion: This study provides a new insight into the pathogenesis of acute leukemia and suggests TXN as a new screening test for the risk for acute leukemia.

Prognostic value of IDH1 mutations identified with PCR-RFLP assay in acute myeloid leukemia patients

BackgroundSomatic mutations in isocitrate dehydrogenase 1 (IDH1) gene occur frequently in primary brain tumors. Recently theses mutations were demonstrated in acute myeloid leukemia (AML). So far, assessment of these mutations relied on the DNA sequencing technique. Aim of the workThe aim of this study was to detect somatic mutations in IDH1 gene using mismatched primers suitable for endonuclease based detection, without the need for DNA sequencing, and to estimate its prognostic value, on patients with de novo AML. MethodsResidual DNA extracted from pretreatment bone marrow (BM) samples of 100 patients with de novo AML was used. The polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP) was adapted to IDH1gene, codon 132 mutations screening. ResultsThe frequency of IDH1 mutations was 13%. In the non-acute promyelocytic leukemia group (non-APL), IDH1 mutations were significantly associated with FLT3-ITD negative patients (p=0.03). Patients with IDH1 mutations did not achieve complete remission (CR). There was a trend for shorter overall survival (OS) in patients with IDH1 mutation compared to those with wild type (p=0.08). ConclusionIDH1 mutations are recurring genetic alterations in AML and they may have unfavorable impact on clinical outcome in adult AML. The PCR-RFLP method allows for a fast, inexpensive, and sensitive method for the detection of IDH1 mutations in AML.

NADH Dehydrogenase Subunit 4 (ND4) Mutations in Pediatric Acute Myeloid Leukemia

AbstractAbstract 1380NADH dehydrogenase subunit 4 (ND4) is encoded by mitochondrial DNA and is an integral component of Complex I, one of the core enzymatic complexes critical for mitochondrial oxidative phosphorylation and regulation of the balance between NADH and NAD+. ND4 mutations have recently been described in adult acute myeloid leukemia (AML). In the current study, we investigated the frequency and prognostic impact of ND4 mutations in 289 pediatric leukemia patients (<= 18 years). Total cellular DNA was isolated from bone marrow or peripheral blood samples at diagnosis (n=289) and at complete remission (n=6) for children treated uniformly within multicenter treatment trials AML-Berlin-Frankfurt-Münster (BFM, n=180) and Dutch Childhood Oncology Group (DCOG, n=109).ND4 mutations were detected by direct sequencing in 13 of 289 (4.5 %) pediatric AML patients. Mutations occurred throughout the ND4 sequence, and included missense mutations (n=10), deletions (n=2) and a nonsense mutation. The most commonly detected mutations were S86N (n=2), delA 11,032–11,038 (n=2), and F50L (n=2). All other mutations were detected in single cases. Four (30.8 %) ND4 mutations were heteroplasmic (i.e. both wild-type and mutated ND4 were detected) and 9 (69.2 %) were homoplasmic (i.e. only mutated ND4 was detected), which is similar to the distribution we previously observed for adult AML patients (37.9% and 62.1%, respectively). Of the 4 heteroplasmic mutations detected in the pediatric AML cohort, 3 are predicted to result in a truncated ND4 protein. The remaining heteroplasmic mutation, which results in an L72P substitution, is predicted to be damaging (PolyPhen2 score = 0.999). Thus all 4 heteroplasmic mutations are expected to interfere with ND4 protein function. In contrast, 3 of the 9 (33.3 %) homoplasmic mutations are within transmembrane regions and only 1 (11.1 %) is predicted to be damaging (S459Y, PolyPhen2 score = 0.906). The 11 predicted transmembrane domains (TMD) of ND4 may be important for mitochondrial proton transport. However, like in adult AML, the presence of ND4 mutations affecting or not affecting a TMD had no impact on pediatric AML patient outcome.Non-tumoral DNA available through samples collected in routine follow-up examinations during complete remission allowed determination of mutation origin (e.g. somatic or germ-line) in 6 cases. Interestingly, the homoplasmic substitutions resulting in F50L, S86N and A131T were each defined to be germline mutations in both adult and pediatric AML samples. The heteroplasmic one base-pair deletion in a stretch of seven adenine residues (11,032–11,038) detected in two pediatric leukemia samples was determined to be somatic in the one case for whom a sample obtained during complete remission was available for analyses. Patient characteristics including age, FAB-subtype, WBC count, cytogenetic subgroup or presence of FLT3-ITD were similar regardless of ND4 mutation status.In accordance with our earlier observations in adult AML, comparison of ND4mutated with ND4wildtype patients demonstrated no significant difference on overall survival (OS, P=.67). In the adult study, a survival advantage was observed for patients with somatic heteroplasmic ND4 mutations. No survival advantage was observed for children with heteroplasmic ND4 mutations, possibly due to limited numbers of ND4mutated patients treated in the BFM and DCOG study groups.Gene expression profiles (GEP) for ND4mutated (n=11) and ND4wild-type (n=188) pediatric AML patients revealed no significant differences. However, 8 probe sets were found to be differentially regulated when GEP for heteroplasmic ND4mutated (n=4) and ND4wildtype (n=187) were compared. Two of these probe sets annotated the SETDB2 (CLLD8, KMT1F) gene, which encodes a histone H3 methyltransferase. Quantitative RT-PCR validated the lower SETDB2 expression as a characteristic of ND4mutated cases (P=.02). SETDB2 contributes to several important cellular functions, including heterochromatin formation, chromatin condensation and transcriptional repression.In summary, ND4 mutations were not predictive for outcome in pediatric AML, but were significantly associated with decreased SETDB2 expression, providing a link between mitochondrial gene mutation and epigenetic control of gene expression. Disclosures:No relevant conflicts of interest to declare.

Subnormal Vitamin D Levels Are Associated with Adverse Outcome In Newly-Diagnosed Similarly-Treated Adult Acute Myeloid Leukemia (AML) Patients.

AbstractAbstract 1041Several studies suggest that subnormal vitamin D levels may be prognostic in a number of malignancies, including non Hodgkin lymphoma, prostate, breast, colon and lung cancer. However, no studies have evaluated the impact of subnormal vitamin D levels on treatment outcome in AML. Vitamin D levels were evaluated in 97 consecutive newly diagnosed similarly treated patients with AML (excluding AML M3). There were 50 (52%) males and 47 (48%) females with a median age of 60 years (range 19–91). The median white blood cell (WBC) count at diagnosis was 18×109/L (range 0.57–555.23). Karyotype was favorable in 11%, intermediate in 50%, adverse in 23%, of unknown significance in 11% and not available in 5%. A total of 74 patients (76%) had de novo AML. Albumin levels were subnormal (<3.5g/dl) in 33 (34%) patients and normal (≥3.5g/dl) in 64 (66%) patients. Body mass index (BMI) was calculated on all patients, normal weight (BMI 18–24.9) 33 (32%) patients, overweight (BMI 25–29.9) 34 (35%) patients, obese (BMI 30–34.9) 16 (16%) and very obese (BMI ≥35) 15 (15%) patients. Induction consisted of cytarabine (100mg/m2 × 7 days), daunorubicin (90mg/m2 for <60 and 60mg/m2, for ≥60 × 3 days) and etoposide (100mg/m2 × 3 days) (ADE 7+3+3).Consolidation therapy consisted of either high-dose cytarabine (47%), ADE (5+2+2) (15%), allogeneic (8%) transplantation, or other/no further treatment (30%). The median follow-up was 8.1(range, <1-66) months. Serum samples were obtained at diagnosis and studied for 25-(OH)-Vitamin D levels using radioimmunoassay. Thirty-four (35%) patients had normal vitamin D levels (32-100 ng/mL), and 63 (65%) patients had levels <32ng/ml.; 34 (35%) patients had levels considered insufficient (20-31.9ng/ml) and 29 (30%) patients were deficient (<20ng/ml). We have studied vitamin D concentrations in a cohort of 100 healthy volunteers from Western New York and found a similar frequency of vitamin D serum concentrations subnormal. Complete remission rate was similar in those with normal and subnormal vitamin D levels (50% vs. 57%; P=0.53). In univariate analysis, WBC count ≥100×109/L was associated with worse progression-free survival (PFS) and overall survival (OS) [14.3 vs. 2.2 months; 95% confidence interval (CI) 8.9 to 21.9 vs. 0.49 to 5.9 for PFS (P=<0.0001) and 17.3 vs. 2.2 months; 95% CI 13.6 to 24.6 vs. 0.49 to 6.7 for OS (P=<0.0001). Similarly, secondary AML was associated with worse PFS and OS [14.9 vs. 6.3 months; 95% CI 9 to 26.7 vs. 4.1 to 10.1 for PFS (P=0.028) and 18.9 vs. 6.7; 95% CI 13.6 to NA vs. 5.6 to 16.7 for OS (P=0.048)]. In addition, unfavorable karyotype, when compared with intermediate and favorable karyotypes, was associated with worse OS [6.6 vs. 18.9 vs. 21.2 months; 95% CI 4.8 to 16.7 vs. 11.5 to NA vs. 14.2 to NA for OS (P=0.04)]. Interestingly, in this cohort, age affected neither PFS nor OS and karyotype had no effect on PFS. Subnormal vitamin D levels were associated with worse PFS and OS [7.9 vs. 16.5 months; 95% CI 5.0 to 12.8 vs. 14.3 to NA for PFS (P=0.007) and 9.2 vs. 21.2 months; 95% CI 6.6 to 18.9 vs. 16.5 to NA for OS (P=0.01)] (Figure 1A and B). Nutritional status, assessed by albumin and BMI, did not affect PFS and OS. In multivariate analyses, only vitamin D (P=0.03 and P=0.049) and WBC count (P=0.02 and P=0.02) retained their statistical significance for PFS and OS. In summary, AML patients with subnormal vitamin D levels had significantly inferior PFS and OS compared to patients with normal vitamin D levels. Additional investigations to validate this observation and determine the mechanisms by which vitamin D levels are associated with inferior survival in AML are warranted. If confirmed, studies of the role of vitamin D supplementation in AML patients would be valuable. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Characterization of CEBPA Mutations and Promoter Hypermethylation in Pediatric Acute Myeloid Leukemia.

Abstract 1605▪▪This icon denotes an abstract that is clinically relevant.Poster Board I-631CCAAT/enhancer binding protein alpha (C/EBPá) function is frequently disrupted in acute myeloid leukemia (AML). This can be caused by different mechanisms, including mutations in CEBPA, the gene encoding for C/EBPá. Recently, promoter hypermethylation resulting in CEBPA silencing has been described. CEBPA mutations are associated with a favorable outcome in adult AML. Recent studies however suggested that the favorable outcome is uniquely associated with CEBPA double-mutated AML (CEBPAdoublemut) (presence of >1 CEBPA mutation), and not with CEBPA single-mutated AML (CEBPAsinglemut). In pediatric AML, data on outcome of CEBPA-mutated AML is limited to one study, showing favorable outcome for CEBPAdoublemut as well as CEBPAsinglemut, which is in contrast with the adult data. So far, data on CEBPA hypermethylation in pediatric AML is lacking.We therefore studied a large pediatric AML cohort (n=252) to characterize CEBPA mutations by sequencing the entire coding region, and CEBPA promoter hypermethylation by methylation-specific PCR (MSP). Survival analyses were performed in 185 patients with de novo AML (excluding t(15;17) and secondary AML) treated on uniform DCOG and BFM protocols. Furthermore, we generated gene expression profiles using the Affymetrix HGU133 plus 2.0 microarrays to compare subgroups with CEBPA aberrations.Thirty four CEBPA mutations were identified in 20/252 diagnostic samples (7.9%). In 14 cases double mutations were present, which combined an N-terminal frame shift mutation with an in-frame mutation in the bZIP region (n=13) or with a frame shift-causing insertion before bZIP (n=1). In 6 cases a single mutation was present; i.e. in-frame bZIP mutation (n=4), or frame shift mutation respectively in the TAD2 domain (n=1) or before the bZIP domain (n=1). CEBPAdoublemut were only present in children above 3 years of age and in FAB M1/2 subtypes, in contrast to CEBPAsinglemut, which presented also in children <3 years of age (1/6) and in other FAB subtypes (3/6). CEBPAdoublemut and CEBPAsinglemut were both exclusively found in cases with a normal karyotype (57% and 33%, respectively) and in cases with ‘other' karyotypes (defined as 'other than t(8;21), inv(16), t(15;17) and MLL-rearrangements'), in 36% and 50%, respectively. However, in both subgroups additional molecular aberrations, i.e. in RAS, FLT3/ITD and WT1, were equally distributed. CEBPAdoublemut patients (n=10) had a significantly better overall survival compared with CEBPAsinglemut (n=5) (5-years pOS 79±13% vs. 25±22%, p=0.04; pEFs 58±16% vs. 30±24%, p=0.16). Furthermore, they showed a trend for favorable outcome compared with CEBPA wild-type AML patients, after excluding CBF-AML cases (n=120; pOS 79±13% vs. 47±5%, p=0.07; pEFS 58±16% vs. 34±4%; p=0.06). Their survival was comparable to the CBF-AML subgroup (n=50) (pOS 91±4%, pEFS 61±8%). Multivariate analysis, including age, WBC, CBF-AML, NPM1 mutations and FLT3/ITD, showed that CEBPAdoublemut were an independent favorable prognostic factor for pOS (HR 0.23; p=0.04) and pEFS (HR 0.32; p=0.03). CEBPA promoter hypermethylation was detected in 3/237 cases, which resulted in CEBPA silencing. Using an unsupervised clustering analysis as previously published by Valk et al. (NEJM 2004) of our de novo AML cases (n=237), CEBPA-mutated cases predominantly aggregated in 1 cluster with the CEBPAsil cases, revealing a common underlying gene expression profile. Two additional cases with silenced CEBPA (CEBPAsil) were identified in this cluster, resulting in 5/237 (2.1%) CEBPAsil cases. All CEBPAsil showed T-lymphoid characteristics, (e.g. high expression of CD7 and high LCK expression). However, NOTCH1 mutations were not found. Three of 5 patients relapsed within 1 year of diagnosis, but the other 2 are in continuous complete remission for 4.8 and 8.5 yrs.In conclusion, CEBPAdoublemut were identified as an independent predictor of good clinical outcome. Hence, if these results could be confirmed in a prospective serie, CEBPAdoublemut may be used for further refinement of risk-group stratification. Of interest, the other cases with CEBPA aberrations, i.e. CEBPAsinglemut and CEBPAsil, seem to predict for poor outcome, in line with data presented in adults. The subgroup with CEBPAsil due to hypermethylation may potentially benefit from the use of demethylating agents. DisclosuresNo relevant conflicts of interest to declare.