Mutations of the Nucleophosmin (NPM1) Gene Are Common in Adult Acute Myeloid Leukemia and Associated with Favorable Prognosis If Present without FLT3-ITD Mutation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 224-224 ◽  
Author(s):  
Christian Thiede ◽  
Sina Koch ◽  
Eva Creutzig ◽  
Christine Steudel ◽  
Thomas Illmer ◽  
...  

Abstract Nucleophosmin (NPM1) is a nucleo-cytoplasmic shuttling protein with multiple functions, including regulation of the p53-ARF pathway. Rearranged NPM1 has been found in a small subgroup of AML patients with t(5;17). Recently, mutations of NPM1 have been described in patients with acute myeloid leukaemia, especially in patients with normal karyotype (Falini et al, NEJM 2005). These mutations lead to an elongated protein which is retained in the cytoplasm. The precise prevalence as well as the long term clinical impact of this mutation is currently unclear. Patients and methods: We investigated 1485 samples from adult patients with newly diagnosed AML and advanced MDS for mutations in exon 12 of the NPM1 gene. The majority of these individuals were treated in the AML96 protocol of the DSIL (former SHG). Mutations in NPM1 exon 12 were screened using genomic DNA from the time of diagnosis and Genescan analysis. In a subgroup, mutations were confirmed by sequencing. In addition, confocal laser scanning microscopy was performed to investigate the localization of mutant NPM1 in cases with novel mutations. Results: A 4-bp insert in the genomic sequence was detected in 408/1485 patients (27.5%). In 229 cases sequenced so far the most common change was the previously reported Type A (80.3%), followed by B (9.2%) and D (3.1) and 13 novel mutations, which showed cytoplasmic localization of NPM1 in all five analyzed cases. The NPM1-mutations were most prevalent in patients with normal karyotype (324/709; 45.7%) compared to 58/686 with karyotype abnormalities (8.5%) (P<.0001). NPM1 mutations were rarely seen in cases with good risk abnormalities [t(8;21): 2/57; inv(16: 2/73; t(15;17): 0/47] but also rarely detected together with high risk cytogenetics [-5/5q-: 3/94;-7/7q-: 5/122; complex: 4/185]. The mutation was found to be associated with high WBC counts, high BM blasts and higher platelet counts (P <.0001). Mutant NPM1 was also more prevalent in females compared to males (33.1 vs 22.9%; P<.00001). Most NPM1 mutations were found in cases with de novo AML, mainly in FAB subgroups M5a, M5b, and M4, and were absent or rare in M3, M0, M6, and M7. Patients with NPM1 alterations had significantly more FLT3-ITD mutations, even if restricted to patients with normal karyotype (NPM1-mut: 43.8% vs. NPM1-wt: 19.9%; p<.0001), whereas a significantly lower rate of MLL-PTD mutations was found (NPM1-mut: 0/207 vs. NPM1-wt: 39/549; P<.0001). To assess the clinical impact, 4 groups were defined based on the NPM1 and FLT3-ITD status for patients with normal karyotype: NPM1-mut/FLT3-ITD neg; NPM1-mut/FLT3-ITD pos; NPM1-wt/FLT3-ITD pos; NPM1-wt/ FLT3-ITD neg. Among these groups, patients having only an NPM1-mutation had significantly better overall survival (OS), disease free survival (DFS) and a lower probability of relapse, compared to all other groups. This was confirmed in a multivariate analysis (HR NPM1-mut/FLT3-ITD neg for OS: 0.76 95% CI: 0.587–.992; DFS: 0.661, 95% CI: 0.449–0.973). In addition, these patients had a significantly lower cumulative incidence of relapse (CIR at 40 months: 37.2%; P = .009). Conclusion: With more than 27%, NPM1-mutations represent the most frequent genetic abnormality in adult AML identified so far. They characterize a specific subset in patients with normal karyotype. If not associated with FLT3-ITD mutations, NPM1 abnormalities appear to identify a subgroup with improved response towards treatment. The mechanistic background remains to be determined.

Blood ◽  
2006 ◽  
Vol 107 (10) ◽  
pp. 4011-4020 ◽  
Author(s):  
Christian Thiede ◽  
Sina Koch ◽  
Eva Creutzig ◽  
Christine Steudel ◽  
Thomas Illmer ◽  
...  

Mutations of the nucleophosmin (NPM1) gene have recently been described in patients with acute myeloid leukemia (AML). To clarify the prevalence as well as the clinical impact of this mutation, we investigated 1485 patients with AML for NPM1 exon 12 mutations using fragment analysis. A 4 bp insert was detected in 408 of 1485 patients (27.5%). Sequence analysis revealed known mutations (type A, B, and D) as well as 13 novel alterations in 229 analyzed cases. NPM1 mutations were most prevalent in patients with normal karyotype (NK) (324 of 709; 45.7%) compared with 58 of 686 with karyotype abnormalities (8.5%; P < .001) and were significantly associated with several clinical parameters (high bone marrow [BM] blasts, high white blood cell [WBC] and platelet counts, female sex). NPM1 alterations were associated with FLT3-ITD mutations, even if restricted to patients with NK (NPM1-mut/FLT3-ITD: 43.8%; versus NPM1-wt/FLT3-ITD: 19.9%; P < .001). The analysis of the clinical impact in 4 groups (NPM1 and FLT3-ITD single mutants, double mutants, and wild-type [wt] for both) revealed that patients having only an NPM1 mutation had a significantly better overall and disease-free survival and a lower cumulative incidence of relapse. In conclusion, NPM1 mutations represent a common genetic abnormality in adult AML. If not associated with FLT3-ITD mutations, mutant NPM1 appears to identify patients with improved response toward treatment.


Cancers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2242
Author(s):  
Silvia Salmoiraghi ◽  
Roberta Cavagna ◽  
Pamela Zanghì ◽  
Chiara Pavoni ◽  
Anna Michelato ◽  
...  

By way of a Next-Generation Sequencing NGS high throughput approach, we defined the mutational profile in a cohort of 221 normal karyotype acute myeloid leukemia (NK-AML) enrolled into a prospective randomized clinical trial, designed to evaluate an intensified chemotherapy program for remission induction. NPM1, DNMT3A, and FLT3-ITD were the most frequently mutated genes while DNMT3A, FLT3, IDH1, PTPN11, and RAD21 mutations were more common in the NPM1 mutated patients (p < 0.05). IDH1 R132H mutation was strictly associated with NPM1 mutation and mutually exclusive with RUNX1 and ASXL1. In the whole cohort of NK-AML, no matter the induction chemotherapy used, by multivariate analysis, the achievement of complete remission was negatively affected by the SRSF2 mutation. Alterations of FLT3 (FLT3-ITD) and U2AF1 were associated with a worse overall and disease-free survival (p < 0.05). FLT3-ITD positive patients who proceeded to alloHSCT had a survival probability similar to FLT3-ITD negative patients and the transplant outcome was no different when comparing high and low-AR-FLT3-ITD subgroups in terms of both OS and DFS. In conclusion, a comprehensive molecular profile for NK-AML allows for the identification of genetic lesions associated to different clinical outcomes and the selection of the most appropriate and effective treatment strategies, including stem cell transplantation and targeted therapies.


Blood ◽  
2010 ◽  
Vol 116 (6) ◽  
pp. 971-978 ◽  
Author(s):  
Christoph Röllig ◽  
Christian Thiede ◽  
Martin Gramatzki ◽  
Walter Aulitzky ◽  
Heinrich Bodenstein ◽  
...  

Abstract We present an analysis of prognostic factors derived from a trial in patients with acute myeloid leukemia older than 60 years. The AML96 trial included 909 patients with a median age of 67 years (range, 61-87 years). Treatment included cytarabine-based induction therapy followed by 1 consolidation. The median follow-up time for all patients is 68 months (5.7 years). A total of 454 of all 909 patients reached a complete remission (50%). Five-year overall survival (OS) and disease-free survival were 9.7% and 14%, respectively. Multivariate analyses revealed that karyotype, age, NPM1 mutation status, white blood cell count, lactate dehydrogenase, and CD34 expression were of independent prognostic significance for OS. On the basis of the multivariate Cox model, an additive risk score was developed that allowed the subdivision of the largest group of patients with an intermediate-risk karyotype into 2 groups. We are, therefore, able to distinguish 4 prognostic groups: favorable risk, good intermediate risk, adverse intermediate risk, and high risk. The corresponding 3-year OS rates were 39.5%, 30%, 10.6%, and 3.3%, respectively. The risk model allows further stratification of patients with intermediate-risk karyotype into 2 prognostic groups with implications for the therapeutic strategy. This study was registered at www.clinicaltrials.gov as #NCT00180115.


HemaSphere ◽  
2019 ◽  
Vol 3 (S1) ◽  
pp. 809
Author(s):  
M. Sciumè ◽  
S. Fabris ◽  
G. Ciceri ◽  
A. Freyrie ◽  
A. Neri ◽  
...  

Blood ◽  
1996 ◽  
Vol 87 (5) ◽  
pp. 1997-2004 ◽  
Author(s):  
G Del Poeta ◽  
R Stasi ◽  
G Aronica ◽  
A Venditti ◽  
MC Cox ◽  
...  

Abstract Cytofluorimetric detection of the multidrug resistance (MDR)-associated membrane protein (P-170) was performed at the time of diagnosis in 158 patients with acute myeloid leukemia using the C219 monoclonal antibody (MoAb). In 108 of these cases the JSB1 MoAb was also tested. An improved histogram subtraction analysis, based on curve fitting and statistical test was applied to distinguish antigen-positive from antigen-negative cells. A marker was considered positive when more than 20% of the cells were stained. At onset, P-170 was detected in 43% of cases with C219 and in 73% of cases with JSB1. There was a strict correlation between C219 and JSB1 positivity, as all C219+ cases were also positive for JSB1 MoAb (P < .001). No relationship was found between sex, age, organomegaly, and MDR phenotype. Significant correlation was found between CD7 and both C219 and JSB1 expression (P < .001 and .001, respectively). C219-negative phenotype was more often associated with a normal karyotype (24 of 55 with P = .030). Rhodamine 123 (Rh123) staining and flow cytometry analysis showed a significantly decreased mean fluorescence in 51 C219+ and 38 JSB1+ patients compared to 42 MDR negative ones (P < .001). The rate of first complete remission (CR) differed both between C219+ and C219- cases and between JSB+ and JSB- ones (30.9% v 71.1% and 35.4% v 93.1%, respectively, P < .001). Of the 21 C219+ patients who had yielded a first CR, 19 (90.4%) relapsed, compared with 28 of 64 (43.7%) C219- patients (P < .001). Of the 28 JSB1+ patients in first CR, 17 (60.7%) relapsed relative to 8 (29.6%) of 27 JSBI- ones (P = .021). A higher rate of relapses among MDR+ compared with MDR- patients was observed both for C219 and JSB1 MoAbs taken separately (C219 80% v 44%; JSB1 52% v 27%), with no relationship to age. The survival rates (Kaplan-Meyer method) were significantly shorter both in C219+ patients and in JSB1+ cases (P < .001). Disease-free survival curves followed this same trend. The combination (C219- JSB1+) identified a subset of patients with an intermediate outcome compared to C219 positive cases. The prognostic value of both markers (C219 and JSB1) was confirmed in multivariate analysis. These results suggest that the assessment of MDR phenotype by flow cytometry may be an important predictor of treatment outcome.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2368-2368
Author(s):  
Tatsuya Suzuki ◽  
Hitoshi Kiyoi ◽  
Kazutaka Ozeki ◽  
Akihiro Tomita ◽  
Ritsuro Suzuki ◽  
...  

Abstract Nucleophosmin (NPM) is a nucleolar protein with multi-functions including centromere duplication, nuclear-cytoplasmic shuttling, ribosomal biogenesis, p53 stability. NPM1 mutations were found in a large number of patients with acute myeloid leukemia (AML) especially with normal karyotype. The mutations lead to the aberrant subcellular localization of NPM protein. However, their impacts on clinical outcome remain controversial. We screened the mutations of NPM1 in 257 AML patients and analyzed the clinical significance. NPM1 mutations were found in 64 of 257 patients (24.9%). Seven types of mutations, including four novel mutations, were identified. NPM1 mutations were associated with normal karyotype, FLT3 mutations (both FLT3-ITD and D835 mutation) but not with other gene alterations such as N-RAS, p53 mutations and partial tandem duplication of the MLL gene. In 190 patients except the M3 subgroup, who were treated according to the protocol of Japan Adult Leukemia Study Group, the multivariate analysis revealed that NPM1 mutation was a favorable factor for achieving complete remission, but significantly associated with relapse. A sequential analysis, using paired samples obtained at diagnosis and relapse in 39 patients, revealed that NPM1 mutations were lost at relapse in 2 of the seventeen patients who had NPM1 mutations at diagnosis and none of the patients, who did not have NPM1 mutations at diagnosis, gained NPM1 mutations at relapse. Our results suggest that NPM-mutated AML should be a distinct subgroup with specific clinical characteristics and outcome. Loss of NPM mutations at relapse implies that NPM mutation is not necessarily a primary genetic alteration and that these leukemic clones could be sensitive to chemotherapy.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2518-2518
Author(s):  
Ulrike Bacher ◽  
Susanne Schnittger ◽  
Wolfgang Kern ◽  
Tamara Weiss ◽  
Claudia Haferlach ◽  
...  

Abstract Acute myeloid leukemia with mutated nucleophosmin (AML NPM1mut) represents about one-third of all adult AML and shows distinctive biological and clinical features. For this reason, AML NPM1mut is planned to be included as a separate category in the revised WHO classification. A yet controversial issue, however, is whether AML NPM1mut with or without multilineage dysplasia (MLD) may differ biologically and clinically, as the presence of MLD might confer a negative prognostic impact. A further feature that was suggested to be typical for NPM1 mutated AML is “cup-like” morphology of blasts. We here analyzed 128 pts with AML NPM1mut and normal karyotype at first manifestation (59 females, 69 males; median age 60.5 years; 23.5–79.3 y). We investigated in parallel cytomorphology from bone marrow and/or peripheral blood, chromosome banding analysis, and molecular analyses. Presence of dysplasia was defined by dysplastic features in ≥50% of cells in the respective hematopoietic lineage as defined by the WHO. A 5% cut-off was taken for the presence of “cup-like” morphology of blasts. All cases were additionally analyzed for the FLT3-ITD, and in 122 pts for the FLT3-TKD. Statistical analysis was performed for overall survival (OS), and event-free survival (EFS) according to Kaplan-Meier using the 2-sided log-rank test. Cox regression analysis related OS and EFS with the analyzed parameters. We found a predominance of the FAB M1 (21.3% of all cases), M2 (33.9%), and M4 subtypes (28.3%). Cup-like morphology in ≥5% of all blasts was observed in 39 of 127 evaluable cases (31.3%) confirming previous observations of an association of the NPM1mut and this specific blast appearance. Molecular characterization detected NPM1 mutation subtype A (n=90/122; 73.8%), B (15/122; 12.3%), and D (7/122; 5.7%), which was in accordance to previous studies. In 56 cases (43.8%) there was a coincidence with an FLT3-ITD. Dysplasia of granulopoiesis was detected in 28/126 (22.2%), of erythropoiesis in 28/104 (26.9%), and of megakaryopoiesis in 57/87 (44.5%) cases in which the respective cell lineage could be analyzed. MLD (≥2 dysplastic hematopoietic lineages) was detected in 28 of 105 evaluable cases (21.9%). Clinical follow-up was available in 104 pts. (median follow-up 12,7 months). CR rate was 83.1% in 77 evaluable pts., and median EFS was 42.1 months in 104 evaluable pts (median OS not reached). An additional FLT3-ITD had a significantly inferior OS (p=0.003) and EFS (p=0.007), confirming the present series being representative. However, the presence of MLD was not significantly related to any endpoint such as CR rate, EFS, or OS. There was no association between MLD and the NPM1-subtype. Also, there was no significant correlation of MLD and the presence of a FLT3-ITD. In conclusion, the presence of MLD in AML NPM1mut with normal karyotype had no impact on CR rate and outcome, whereas coincidence of FLT3-ITD significantly worsened prognosis. These results give further evidence that AML with NPM1mut AML is a unique biological entity with clinical course mainly influenced by FLT3-ITD coincidence. These data do not support any additional prognostic influence of MLD in this AML subtype.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4676-4676
Author(s):  
Seo-Jin Park ◽  
Hyun-Sook Chi ◽  
Kyung Ran Jun ◽  
Sook Kyoung Min ◽  
Seongsoo Jang ◽  
...  

Abstract Abstract 4676 INTRODUCTION Mutations of the nucleophosmin gene (NPM1) occur in up to 40-50% of adult acute myeloid leukemia (AML) with a normal karyotype and are associated with a higher frequency of fms-like tyrosine kinase-3 internal tandem duplications (FLT3-ITD) and responsiveness to induction chemotherapy. The incidence of NPM1 mutations in Caucasians have been previously reported in several studies whereas there have been few reports from Asian countries including Japan, China, and Taiwan. The objectives of our study was to determine the prevalence of NPM1 mutations and distribution of AML subtypes in the normal karyotype AML Korean population in addition to establishing an easily applicable yet reliable method to indentify these mutations. We also examined treatment outcomes and survival (relapse-free survival (RFS) and overall survival (OS)) by stratifying them into groups according to NPM1 and FLT3-ITD mutation status. METHODS We retrospectively analyzed the prevalence of NPM1 mutations in 185 patients with normal karyotype AML diagnosed between 2002 and 2009. Genomic DNA extracted from bone marrow aspirate specimens obtained at diagnosis was amplified by PCR, followed by analysis on an ABI 3130 Genetic Analyzer (Applied Biosystems) by capillary electrophoresis. Cases found to have mutation peaks at 174bp by Gene Mapper ID v3.2 software (Applied Biosystems) were further analyzed by direct sequencing of exon 12 of NPM1 gene. Follow-up data was reviewed by retrospective chart review for treatment outcome and survival analyses. Among the 185 AML patients, 18 with less than a 1-month follow-up period were excluded since they could not be sufficiently evaluated. RESULTS Mutations in exon 12 of NPM1 were found in 37 of 185 (20.0%) normal karyotype AML patients and were composed of TCTG duplications (Type A, 32/37, 86.5%), 3 previously reported variants, and 2 new variants previously not reported. Mutations were most frequently seen in AML M1 patients (12/37, 32.4%) and other subtypes such as M2, and M4 were often observed. NPM1 mutations were particularly associated with CD34-negativity (<0.0001) and higher bone marrow blast (%) at diagnosis (p=0.0067). There was a mild trend towards frequent FLT3-ITD mutations in NPM1+ patients in comparison to the NPM1- group (35.1% and 19.6%, p=0.0787). After exclusion of the 18 patients lost during follow-up, no significant differences in RFS (8.5 and 10.8 months, p=0.7922) and OS (11.5 and 13.6 months, p=0.6147) were observed between the NPM1+ and NPM1- groups. Stratification into good (NPM1+/FLT3-ITD-), intermediate (NPM1-/FLT3-ITD- & NPM1+/FLT3-ITD+), and poor (NPM1-/FLT3-ITD+) prognostic groups did not reveal significant differences in median values of RFS and OS (in months; RFS, 16.0 and 13.8 and 7.3, p=0.1872; OS, 16.0 and 10.8 and 7.3, p=0.3661). However, the Kaplan-Meier survival analysis of these stratified prognostic groups showed a trend toward a difference in RFS (p=0.084) and a significantly longer OS in the NPM1+/FLT3-ITD- (good prognostic) group (p=0.031). CONCLUSIONS The prevalence of NPM1 mutations in normal karyotype AML patients in Koreans was lower than those reported in Western studies. In areas with low prevalence, a screening method to detect mutations enables rapid reporting with only selective cases requiring the labor-intensive direct sequencing step. In accordance with previous studies, a significantly longer OS in the NPM1+/FLT3-ITD- group suggests that NPM1+ may be associated with a favorable outcome. However, discordant parameters such as prevalence and RFS may signify that elucidation of the prognostic significance of NPM1 mutations in different ethnic groups may be necessary. Thus, NPM1 mutation studies should be considered in the diagnostic work-up of all AML patients with a normal karyotype given its role as a prognostic marker. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2534-2534
Author(s):  
Yeo-Kyeoung Kim ◽  
Il-Kwon Lee ◽  
Dennis Dong Hwan Kim ◽  
Chul Won Jung ◽  
Jun-Ho Jang ◽  
...  

Abstract Abstract 2534 Background: Acute myeloid leukemia with normal karyotype (AML-NK) is known to be heterogeneous in the molecular level. Accordingly, it has become more critical to dissect this group of patients according to their prognosis using a molecular genetic technology. We attempted to analyze the incidence and prognostic implication of genetic abnormalities on survival in 426 adult patients with AML-NK. Methods: A total of 67 AML-NK patients achieved complete remission (CR), candidate mutations in 21 genes were identified by whole exome sequencing which has 41–89× coverage and by single-nucleotide polymorphism array analysis using marrow mononuclear cells at diagnosis of AML-NK. Subsequently, mutation analysis of 11 genes (i.e. FLT3/ITD, NPM1, DNMT3a, IDH1, IDH2, TET2, NRAS, WT1, DNAH11, SF3B1, and PHF6) which are known to be involved in the pathogenesis of hematologic diseases, were performed using Sanger sequencing in another subset of 359 AML-NK patients as a validation cohort. Results: Of 426 patients in total (median age: 51, ranges: 15–85), FLT3/ITD, NPM1, and DNMT3a mutations were associated with higher leukocytes counts at presentation of AML-NK. In 284 patients who received standard remission induction (RI) chemotherapy (excluding 119 patients with conservative treatment and 22 early death/1 follow-up loss after RI chemotherapy), those with FLT3/ITD mutation were significantly associated with a higher risk of relapse (p=0.02), a shorter leukemic-free survival duration (LFS)(p<0.01) or overall survival (OS) (p=0.01). Accordingly, we divided the patients into FLT3/ITD+ and FLT3/ITD− population, and analyzed their treatment outcomes according to the other mutations. In the FLT3/ITD− group (n=200), those with NPM1 mutation showed a higher CR rates after one or two cycles of RI chemotherapy (p<0.01) and a longer OS duration (p<0.01), hazard ratio (HR) 0.43, 95% confidence interval (CI) 0.25–0.73, adjusted by other clinical variables including age, leukocyte counts at diagnosis, and transplantation (Figure 1). In the FLT3/ITD+ patients (n=84), NPM1 mutation was found to be a favorable prognostic factor showing a lower relapse rate (p=0.00), a longer LFS duration (p<0.01, HR 0.35, 95% CI 0.18–0.70), and OS duration (p=0.04, HR 0.55, 95% CI 0.31–0.98) in NPM1 mutated patients. In addition, OS was significantly different in favor of those with IDH2, especially R140Q IDH2 mutation, (p=0.04, HR 0.30, 95% CI 0.09–0.99), whereas DNAH11 mutation was associated with inferior OS (p<0.01, HR 5.78, 95% CI 1.65–20.25). Accordingly, we stratified the FLT3/ITD+ patients into three subgroups according to the NPM1, IDH1/2 and DNAH11 mutation status, Group 1: NPM1 mutation and IDH1 or 2 mutations (n=16), Group 2: isolated DNAH11 mutation (n=4) and Group 3: all mutations were negative (n=64). The group 1 showed significantly better OS than group 2 (p<0.01, HR 16.90, 95% CI 3.48–82.15) or group 3 (p<0.01, HR 3.40, 95% CI 1.20–9.55) (Figure 2). In a subgroup analysis of younger patients less than 60 years of age, similar outcomes were also observed in favor of group 1 in terms of OS (data not shown). Conclusion: Our study confirmed that NPM1 mutation is an independent prognostic factor in adult patients with AML-NK not harboring FLT3/ITD mutation. In addition, several other genetic markers were identified as prognostic including IDH1/2 or DNAH11 mutations as well as NPM1 mutation in a subgroup of AML-NK patients with FLT3/ITD mutation. Disclosures: No relevant conflicts of interest to declare.


2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 7052-7052
Author(s):  
B. C. Medeiros ◽  
J. R. Gotlib ◽  
S. E. Coutre ◽  
C. Jones ◽  
S. A. Khan ◽  
...  

7052 Background: High treatment-related mortality and low response rates often discourage elderly patients with acute myeloid leukemia from receiving treatment. Previous data demonstrate that only patients lacking expression of O6-alkylguanine-DNA alkyltransferase (AGAT) in leukemic blasts are sensitive to temozolomide. Protracted exposure to low doses of temozolomide can significantly inhibit AGAT enzymatic activity. Methods: Phase II clinical trial of tailored temozolomide therapy to high-risk AML patients according to AGAT methylation promoter status. Patients demonstrating evidence of AGAT promoter methylation were stratified to conventional doses of temozolomide at 200 mg/m2 orally x 7 days. Patients demonstrating lack of AGAT promoter methylation (unmethylated) received protracted doses of temozolomide (100 mg/m2 orally x 14 days) followed by conventional doses of temozolomide. Patients who achieved CR were given up to 5 consolidation treatments. Results: Fifteen patients have completed treatment to date. The median age was 78 (68–83) and nine were male. De novo AML was diagnosed in eight patients and five patients had s-AML. Nine patients had a normal karyotype and three patients had a complex karyotype. Two patients had only a NPM1 mutation and one had NPM1mut/FLT3-ITD. In 13 patients, the AGAT promoter was found to be unmethylated. AGAT protein was present in 5/11 patients. All patients had an intact mismatch repair pathway. Thirteen patients had HCT-CI scores of 0–2. Six patients (6/13) achieved a complete remission (CR) after 1 cycle of therapy (1/2 for patients with methylated and 5/11 for patients with unmethylated AGAT promoter). Nonhematologic toxicities were minimal. Drug-related hematologic toxicities were difficult to distinguish from disease-related cytopenias. Three patients remain in CR with a median duration of 22 weeks (14–36 weeks). Seven patients have died from disease progression, while two patients died of neutropenic sepsis (early deaths). With a median follow-up of 38 weeks (10–48), the median overall survival for the entire population is 12 weeks (3.5 - 38) weeks (responders 26.5 weeks). Conclusions: These preliminary results suggest that temozolomide therapy may be individually tailored to elderly patients with AML according to AGAT promoter status. [Table: see text]


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