ALBERT

Description: Monitoring of measurable residual disease (MRD) provides prognostic information in patients with Nucleophosmin1 mutated (NPM1mut) acute myeloid leukemia (AML) and represents a powerful tool to evaluate treatment effects within clinical trials. We determined NPM1mut transcript levels (TL) by RQ-PCR and evaluated the prognostic impact of NPM1mut MRD and the effect of gemtuzumab ozogamicin (GO) on NPM1mut TL and the cumulative incidence of relapse (CIR) in patients with NPM1mut AML enrolled in the randomized phase III AMLSG 09-09 trial. 3733 bone marrow (BM) and 3793 peripheral blood (PB) samples from 469 patients were analyzed. NPM1mut TL log10 reduction ≥3 and achievement of MRD negativity in BM and PB were significantly associated with a lower CIR rate, after two treatment cycles and at end of treatment (EOT). In multivariate analyses, MRD positivity consistently revealed as poor prognostic factor in BM and PB. With regard to treatment effect, the median NPM1mut TL were significantly lower in the GO-Arm across all treatment cycles, resulting in a significantly higher proportion of patients achieving MRD negativity at EOT (56% vs 41%; P=.01). The betterreduction of NPM1mut TL after two treatment cycles in MRD-positive patients by the addition of GO led to a significantly lower CIR rate (4-year CIR 29.3% vs 45.7%, P=.009). In conclusion, the addition of GO to intensive chemotherapy in NPM1mut AML resulted in a significantly better reduction of NPM1mut TL across all treatment cycles leading to a significantly lower relapse rate. The AMLSG 09-09 trial was registered at www.clinicaltrials.gov as #NCT00893399.

Description: Background: Measurable residual disease (MRD), as determined by quantitation of Nucleophosmin 1-mutated (NPM1mut) transcript levels (TL), provides significant prognostic information independent of other risk factors in patients (pts) with acute myeloid leukemia (AML). This is also addressed by the 2017 European LeukemiaNet (ELN) risk stratification system, which recommends taking into account results from MRD monitoring when selecting the appropriate post-remission therapy. Furthermore, MRD monitoring provides a powerful tool to evaluate treatment effects within clinical trials investigating novel therapies. Aims: To determine the impact of the anti-CD33 immunotoxin Gemtuzumab-Ozogamicin (GO) on kinetics of NPM1mut TL in pts with newly diagnosed NPM1mut AML [18 to 82 years (yrs), median age 58 yrs] enrolled in our randomized Phase III AMLSG 09-09 study (NCT00893399). In this study GO was randomized (1:1) to standard chemotherapy plus ATRA. Patients and Methods: In total, 588 evaluable pts were enrolled in the clinical AMLSG 09-09 study. Standard treatment comprised two cycles of induction therapy with A-ICE (ATRA, idarubicin, cytarabine, etoposide; arm A) followed by three consolidation cycles of high-dose cytarabine (n=371, 63%) or allogeneic hematopoietic cell transplantation (n=42, 8%). In the investigational arm (arm B), GO (3 mg/m²) was given at d1 of each induction and in the first consolidation cycle. 296 pts were randomized to arm A and 292 pts to arm B. For this correlative study, outcome analysis was restricted to the clinical endpoint cumulative incidence of relapse (CIR) due to study protocol requirements allowing overall survival analysis to be performed only two years after the last pt had been enrolled. MRD monitoring was performed in a total 503 pts for whom at least one bone marrow (BM) sample was available using RQ-PCR technique; the median follow-up (FU) of the 503 pts was 2.8 yrs. NPM1mut TL (ratio of NPM1mut/ABL1 transcripts x 104) were determined by RQ-PCR (sensitivity 10-5 to 10-6). Results: In total, 3711 BM samples were analyzed (at diagnosis, n=415; during treatment, n=1765; during FU, n=1531). Both study arms were well balanced with regard to pts characteristics and pretreatment NPM1mut TL. First, we evaluated the impact of GO on kinetics of NPM1mut TL during treatment. After the first induction cycle, median NPM1mut TL were significantly lower in the investigational arm (p=.001) and this was true for all subsequent treatment cycles [after induction II (p=.008), consolidation I (p

Description: Background: Mutations of the NPM1 gene are one of the most frequent genetic aberrations in adult AML. AML with mutated NPM1 is categorized as a disease entity according the WHO-2016 classification and clinically associated with female sex, high white blood cells at diagnosis, normal karyotype and high CD33 antigen expression. We recently showed that patients with NPM1-mutated AML benefit from all-trans retinoic acid (ATRA) as adjunct to intensive induction therapy (Ann Hematol. 2016; 95:1931-1942; Haematologica. 2009;94:54-60). Based on the regular high CD33 expression in AML with mutated NPM1 we hypothesized that gemtuzumab ozogamicin (GO) added to intensive therapy with ATRA may further improve clinical outcome in AML with mutated NPM1. Aim: To evaluate GO in combination with intensive induction and consolidation therapy and ATRA in NPM1 mutated AML within the randomized AMLSG 09-09 trial (NCT00893399) Methods: Between May 2010 and September 2017, patients ≥18 years of age and considered eligible for intensive therapy were randomized up-front for open-label treatment with GO. Induction therapy consisted of two cycles of A-ICE (idarubicin 12mg/m² iv, day 1,3,5 [in induction II and for patients 〉60 years reduced to d 1, 3]; cytarabine 100mg/m² continuous iv, day 1 to 7; etoposide 100mg/m² iv, day 1-3 [in induction II and for patients 〉60 years reduced to d 1, 3]; ATRA 45 mg/m²/day po on days 6-8 and 15mg/m² days 9-21, +/- GO 3mg/m² iv day 1). Consolidation therapy consisted of 3 cycles of high-dose cytarabine (HiDAC; 3g/m² [reduced to 1g/m² in patients 〉60 years] bid, days 1-3; Pegfilgrastim 6mg sc, day 10; ATRA 15 mg/m²/day po, days 4-21; +/- GO 3mg/m² on day 1 [first consolidation only]). The primary endpoints of the study were event-free survival (EFS) as early endpoint tested 6 months and overall survival (OS) tested 4 years after study completion with sequential testing according the fallback procedure described by Wiens (Statistics 2003;2:211-215). This report focusses on the early EFS endpoint. Further secondary endpoints were response to induction therapy, cumulative incidence of relapse (CIR) and cumulative incidence of death (CID). Results: In total 588 patients were evaluable for analysis (n=296, standard-arm; n=292 GO-arm). Median age was 58.7 years (range, 18.4-82.3 years), ECOG performance status was 0 in 34.1% and 1 in 55.1%, and FLT3-ITD was present in 16.8% of the patients, with baseline characteristics well balanced between the two arms. After first induction therapy death rates were significantly higher in the GO-arm (7.5%) (p=0.02) compared to the standard-arm (3.4%); in both study-arms causes of death were mainly infections. Following induction therapy complete remission (CR) and CR with incomplete count recovery (CRi) were 88.5% and 85.3% (p=0.28), refractory disease (RD) 6.1% and 5.1% (p=0.72), death 5.4% and 9.6% (p=0.06) in the standard- and GO-arm, respectively. Due to prolonged thrombocytopenia after second induction therapy in the GO-arm, the protocol was amended in that GO was omitted in second induction and first consolidation cycles, if prolonged cytopenias were observed during first induction therapy. The study treatment was completed in 197 and 171 patients (p=0.11), allogeneic hematopoietic cell transplantation in first CR was performed in 18 and 21 patients (p=0.51) in the standard- and GO-arm, respectively. Median follow-up was 2.6 years (95%-CI, 2.4-3.1 years). Two- and 4-year EFS were 53% (95%-CI, 48-60%) and 58% (95%-CI, 52%-64%), and 44% (95%-CI, 38-52%) and 52% (95%-CI, 46%-59%) in the standard- and GO-arm, respectively. According to the pre-specified significance level of 0.025, EFS in the GO-arm was not different to that in the standard-arm (p=0.21). In patients achieving CR/CRi after induction therapy, CIR was significantly reduced in the GO-arm compared to the standard-arm (p=0.018), whereas no difference in CID was noted between both arms (p=0.89). Conclusion: The addition of GO to intensive induction therapy with ICE plus ATRA was associated with a higher death rate. In patients achieving a CR/CRi after induction therapy significantly less relapses occurred in the GO- compared to the standard-arm. Disclosures Schlenk: Pfizer: Research Funding, Speakers Bureau. Paschka:Astex: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees, Travel support; Otsuka: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Sunesis: Membership on an entity's Board of Directors or advisory committees; Bristol-Meyers Squibb: Other: Travel support, Speakers Bureau; Jazz: Speakers Bureau; Amgen: Other: Travel support; Janssen: Other: Travel support; Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Speakers Bureau; Agios: Membership on an entity's Board of Directors or advisory committees; Takeda: Other: Travel support. Fiedler:Amgen: Other: support for meetíng attendance; Gilead: Other: support for meeting attendance; Pfizer: Research Funding; Amgen: Research Funding; Amgen: Patents & Royalties; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; ARIAD/Incyte: Membership on an entity's Board of Directors or advisory committees, support for meeting attendance; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSO: Other: support for meeting attendance; Teva: Other: support for meeting attendance; JAZZ Pharmaceuticals: Other: support for meeting attendance; Daiichi Sankyo: Other: support for meeting attendance. Lübbert:Cheplapharm: Other: Study drug; Celgene: Other: Travel Support; Janssen: Honoraria, Research Funding; TEVA: Other: Study drug. Götze:Novartis: Honoraria; Takeda: Honoraria, Other: Travel aid ASH 2017; JAZZ Pharmaceuticals: Honoraria; Celgene: Honoraria, Research Funding. Schleicher:Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Investigator; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Ipsen: Membership on an entity's Board of Directors or advisory committees; Eissai: Other: Investigator; Astra Zeneca: Other: Investigator; Pfizer: Speakers Bureau; Janssen: Speakers Bureau; Celgene: Speakers Bureau. Greil:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MSD: Honoraria, Research Funding; Janssen: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Honoraria, Research Funding; Astra Zeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sandoz: Honoraria, Research Funding; Amgen: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Heuser:Novartis: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Astellas: Research Funding; BergenBio: Research Funding; Karyopharm: Research Funding; Daiichi Sankyo: Research Funding; Sunesis: Research Funding; Tetralogic: Research Funding; Bayer Pharma AG: Consultancy, Research Funding; StemLine Therapeutics: Consultancy; Janssen: Consultancy. Ganser:Novartis: Membership on an entity's Board of Directors or advisory committees. Döhner:Agios: Consultancy, Honoraria; Pfizer: Research Funding; Sunesis: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Astex Pharmaceuticals: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; AROG Pharmaceuticals: Research Funding; Agios: Consultancy, Honoraria; Bristol Myers Squibb: Research Funding; Celator: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Astex Pharmaceuticals: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AROG Pharmaceuticals: Research Funding; Jazz: Consultancy, Honoraria; Jazz: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Pfizer: Research Funding; Sunesis: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Research Funding; Seattle Genetics: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Celator: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding.

Description: Background: The MYC proto-oncogene encodes a DNA-binding factor that can induce widespread changes in gene expression profiles (GEP). Activation of MYC is a hallmark of aggressive lymphomas and frequently observed in Richter transformation of CLL. In contrast, the role of MYC-related pathogenic networks is less clearly defined in untransformed CLL. Aims: We hypothesized that MYC activation in CLL could lead to specific GEP associated with aggressive disease. We combined the analysis of genomic copy number alterations (CNA) and GEP involved in MYC pathway activation on specimens from patients registered on the CLL8 trial (front line therapy FC vs. FCR). Methods: GEP were derived from CD19-enriched CLL samples (n=337, Human Exon 1.0 ST, Affymetrix) and analysis of CNA was performed based on availability of DNA (n=309, Human SNP Arrays 6.0, Affymetrix). Sample work-up upon trial registration included FISH and TP53 mutation analysis. Results: Genomic gains involving the MYC locus on 8q24.21 were observed in 4.5% of cases. To test the hypothesis of specific GEP associated with MYC activation, we explored the distribution of cases with MYC gain using an unsupervised approach on GEP. After consensus clustering (k=6 clusters) of variably expressed genes (SD〉0.5), cases with MYC gain were non-randomly distributed and showed a characteristic pattern. Preferential enrichment was observed in one cluster ("MYC-CNA" group, comprising 40% of all cases) with 64% of MYC gains. Gene set enrichment analysis (GSEA) confirmed overrepresentation of MYC target genes (gene set: HALLMARK_MYC_TARGETS_V1, FDR

Description: Patients with acute myeloid leukemia (AML) and a FLT3 internal tandem duplication (ITD) have poor outcomes to current treatment. A phase 2 hypothesis-generating trial was conducted to determine whether the addition of the multitargeted kinase inhibitor midostaurin to intensive chemotherapy followed by allogeneic hematopoietic cell transplantation (alloHCT) and single-agent maintenance therapy of 12 months is feasible and favorably influences event-free survival (EFS) compared with historical controls. Patients 18 to 70 years of age with newly diagnosed AML and centrally confirmed FLT3-ITD were eligible: 284 patients were treated, including 198 younger (18-60 years) and 86 older (61-70 years) patients. Complete remission (CR) rate, including CR with incomplete hematological recovery (CRi) after induction therapy, was 76.4% (younger, 75.8%; older, 77.9%). The majority of patients in CR/CRi proceeded to alloHCT (72.4%). Maintenance therapy was started in 97 patients (34%): 75 after alloHCT and 22 after consolidation with high-dose cytarabine (HiDAC). Median time receiving maintenance therapy was 9 months after alloHCT and 10.5 months after HiDAC; premature termination was mainly a result of nonrelapse causes (gastrointestinal toxicity and infections). EFS and overall survival at 2 years were 39% (95% confidence interval [CI], 33%-47%) and 34% (95% CI, 24%-47%) and 53% (95% CI, 46%-61%) and 46% (95% CI, 35%-59%) in younger and older patients, respectively. EFS was evaluated in comparison with 415 historical controls treated within 5 prospective trials. Propensity score-weighted analysis revealed a significant improvement of EFS by midostaurin (hazard ratio [HR], 0.58; 95% CI, 0.48-0.70; P 〈 .001) overall and in older patients (HR, 0.42; 95% CI, 0.29-0.61). The study was registered at www.clinicaltrials.gov as #NCT01477606.

Description: Background:Recent publications suggest important roles of lysine methyltransferase 2C (KMT2C, located on 7q) and sprouty 4 (SPRY4, located on 5q) as candidate genes in leukemogenesis of acute myeloid leukemia (AML). The prognostic impact of the gene expression levels (ELs) of both genes on outcome in AML patients (pts) is currently unclear. Aim:To evaluate the prognostic impact of KMT2C and SPRY4 expression in correlation to clinical characteristics and genetic abnormalities assessed at diagnosis in a cohort of intensively treated adult AML pts. Methods: We retrospectively studied 268 AML pts (median age, 48 years; range, 17-60 years) who had been enrolled on 2 AML SHG trials (0295 and 0199, n=148; only normal cytogenetics pts (CN)) and the SAL-AML2003 trial (n=120; only abnormal cytogenetics pts (CA)). Acute promyelocytic and core-binding factor leukemia pts were excluded. Type of AML was de novo in 235 (88%), secondary in 19 (7%) and therapy-related in 14 (5%) of the 268 pts. Regarding baseline characteristics, CN pts had significantly higher white blood counts (WBC; p=0.001) and blast cells in peripheral blood (p=0.02) as compared to CA pts; all other factors were comparable. Cytogenetic analyses could be performed in 263 (98%) of the 268 pts. Cytogenetic risk classification according to ELN guidelines was intermediate-II in 55 (47%) and adverse in 63 (53%) of the CA pts, respectively. Abnormalities (abn) of 5q were present in 21 (18%) and abn of 7q in 16 (14%) of the CA pts. NPM1 and FLT3-ITD were analyzed in 145 (98%) of the CN pts. Of those, 59 (41%) were only NPM1 positive (pos), 12 (8%) were only FLT3-ITD pos, 34 (23%) were double pos and 40 (28%) were double negative (neg). KMT2C and SPRY4 ELs, normalized to ABL1and log2-transformed for analysis, were measured in triplets on cDNA obtained at diagnosis by RT-qPCR. Based on cDNA availability, KMT2C ELs could be analyzed in 143 (97%) of the CN and in all of the 120 CA pts, respectively. SPRY4 ELs could be measured in 30 (21%) of the CN and 107 (89%) of the CA pts, respectively. Results: KMT2C ELs were significantly lower in CN pts with de novo as compared to secondary AML (p= 0.02), whereas there was no difference in CA pts. No significant association was found for SPRY4 and type of AML. KMT2C ELs were significantly lower in FLT3-ITD pos as compared to FLT3-ITD neg CN pts (p=0.046), whereas there was no difference for SPRY4 ELs between the two groups (p=0.57). In addition, there was a significantly lower KMT2C expression in CN pts with intermediate-I risk as compared to NPM1 pos / FLT3-ITD neg pts (p=0.01). Regarding CA pts, there was no difference of KMT2C or SPRY4 ELs in adverse as compared to intermediate-II risk pts (p=0.08; p=0.20, respectively). When focusing on specific subgroups, KMT2C ELs were significantly lower in abn7q CA pts as compared to those without abn7q (p=0.002), whereas there was no difference of SPRY4 ELs in CA pts with or without abn5q (p=0.27). In univariate analysis higher SPRY4 ELs showed a significant favorable impact on relapse-free (RFS, p=0.03) and a trend towards a beneficial impact on overall survival (OS, p=0.06) for CA patients. A similar effect for KMT2C was not observed (RFS, p=0.96; OS, p=0.92). In subgroup analyses of pts with adverse risk cytogenetics, there was no impact of KMT2C or SPRY4 ELs on RFS (p=0.73; p=0.39) or OS (p=0.49; p=0.46), respectively. The same was true for FLT3-ITD pos CN pts (RFS, p=0.73; p=0.37; OS, p=0.91; p=0.36, respectively). In multivariate analyses on RFS and OS in CA pts including age, gender, KMT2C and SPRY4 ELs, logarithm of WBC, blast cells in bone marrow and cytogenetic risk group as variables, only higher age (OS, Hazard ratio (HR),1.28 per 10 years; 95%-confidence interval (CI): 1.02-1.59; p=0.03) and complex karyotype as compared to intermediate-II risk cytogenetics (RFS, HR: 2.25; 95%-CI: 1.20-4.22; p=0.01; OS, HR: 2.97; 95%-CI: 1.65-5.35; p

Description: Introduction: Internal tandem duplication of the FLT3 gene (FLT3-ITD), resulting in duplication of 3 to more than hundreds of nucleotides, are present in approximately 25% of adults with newly diagnosed AML. Several studies have shown that ITD mutations are associated with poor prognosis due to a high relapse rate, in particular in case of a high mutant to wild-type allele ratio and/or insertion site in the beta1-sheet of the tyrosine kinase domain-1 (beta1-sheet). Aims: To investigate the relationship between ITD insertion site and patient outcome, Roche 454 next generation sequencing (NGS) was performed in 452/555 (81.4%) FLT3-ITD positive patients (pts) enrolled into the RATIFY trial (NCT00651261). Results: NGS identified 908 ITDs with up to 9 ITDs per case (1 ITD: n=210, 46.5%; 2 ITDs: n=131, 29.0%; 3 ITDs: n=58, 12.8%; 4 ITDs: n=24, 5.3%; 5 ITDs: n=18, 4.0%; 6 ITDs: n=3, 0.7%; 7 ITDs: n=7, 1.5%; 9 ITDs: n=1, 0.2%). Median ITD-size was 45 nucleotides (range, 6-246); all ITDs were in-frame with direct head-to-tail orientation. According to the 4 functional groups, 488 ITDs (53.7%) were located within the juxtamembrane domain (JMD), 155 ITDs (17.1%) within the hinge region, 211 ITDs (23.2%) within the beta1-sheet, and 54 ITDs (5.9%) 3´of beta1-sheet. ITD size strongly correlated with insertion site, in that the more C-terminal the insertion site, the longer the size of the inserted fragment (P

Description: Background: Recently, the oral multitargeted small molecule FLT3 inhibitor midostaurin (M) was approved for treatment of FLT3-mutated AML in combination with standard chemotherapy. In the international RATIFY (NCT00651261) trial, addition of M led to superior overall and event-free survival compared to placebo, thus defining a new standard of care in this AML subset (Stone RM et al. NEJM 2017). Although not powered for subgroup analyses, M showed consistent effects across all FLT3 mutation strata [tyrosine kinase domain (TKD); internal tandem duplication (ITD) with low (0.05-0.7; ITDlow) or high (〉0.7; ITDhigh) allelic ratio] suggesting significant off-target activity beyond FLT3 inhibition. Aim: We aimed to comprehensively profile the mutational landscape of FLT3 mutated (FLT3mut) AML in a large, well characterized cohort of patients (pts) treated within the RATIFY trial using a high-throughput targeted sequencing (HTS) approach. Methods: HTS was performed on the entire coding region of 262 genes involved in hematologic malignancies including 20 genes that encode kinases targeted by M (M kinome, MK). Pretreatment peripheral blood (PB; 14%) or bone marrow (BM; 86%) specimens were available from 475 (66%) of 717 FLT3mut AML RATIFY pts. Libraries were prepared using SureSelectXT custom solutions (Agilent). Paired-end sequencing was carried out on a HiSeq platform (Illumina). FLT3 mutation (mut) status was available for all pts [TKD: 24%; ITD: 76% (ITDlow: 45%; ITDhigh:31%)], and cytogenetic data for 454 pts (96%). Results: An average sequencing depth of 978x was obtained for all pts. In sum, 1815 mut (missense: 49%; indels: 40%; nonsense: 7%; other: 3%) were identified with a mean of 3.8 mut per pt (FLT3 strata; TKD: 4; ITDlow: 4; ITDhigh: 3.6).Overall, recurrent mut (〉5% of all pts) were found in NPM1 (61%), DNMT3A (39%), WT1 (21%), TET2 (12%), RUNX1 (11%), NRAS (11%), PTPN11 (9%), ASXL1 (8%), IDH1 (8%), IDH2 (7%; R140 only), and SMC1A (6%). In contrast, TP53 (1%) and biallelic CEPBA (1%) mut were rare events. This was also true for aberrations of the MK (7% in total) with KIT (2%), MAP3K11 (1%), and NTRK3 (1%) being most frequently mutated. When stratified according to FLT3mut type, mut in NRAS (24% vs 7%, p1 class-defining lesion), emphasizing the need for further refinement of this classification. When focusing on these two groups, N and CS had comparable FLT3mut patterns (TKD: 24% vs 21%; ITDlow: 44% vs 45%; ITDhigh: 32% vs 33%), whereas N more frequently correlated with a normal karyotype (N: 91% vs CS: 63%). With respect to clinical characteristics, no differences between N and CS in terms of age, white blood cells, platelets, PB and BM blasts, as well as history of MDS were observed. Conclusion: In this comprehensive sequencing approach, we could further delineate the molecular pattern of FLT3mut AML. Here, FLT3-ITD and -TKD groups exhibited remarkable differences in cooperating pathways, highlighting distinct biologic features in the leukemogenesis of FLT3mut AML. Overall, mut of MK genes were rare events, not fully explaining the complexity of M off-target effects. Understanding the underlying disease mechanism will potentially provide useful information on prognosis and prediction of response to M. Further analyses including correlation with clinical outcome are ongoing. Support: U10CA180821, U10CA180861, U10CA180882, U24CA196171 Disclosures Bullinger: Janssen: Speakers Bureau; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau; Pfizer: Speakers Bureau; Sanofi: Research Funding, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; Bayer Oncology: Research Funding. Gathmann:Novartis: Employment. Larson:Ariad/Takeda: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; BristolMyers Squibb: Consultancy, Research Funding. Medeiros:Genentech: Employment; Celgene: Consultancy, Research Funding. Tallman:ADC Therapeutics: Research Funding; AROG: Research Funding; BioSight: Other: Advisory board; Orsenix: Other: Advisory board; AbbVie: Research Funding; Daiichi-Sankyo: Other: Advisory board; Cellerant: Research Funding. Tiecke:Novartis: Employment. Pallaud:Novartis: Employment. Ehninger:Cellex Gesellschaft fuer Zellgewinnung mbH: Employment, Equity Ownership; GEMoaB Monoclonals GmbH: Employment, Equity Ownership; Bayer: Research Funding. Ganser:Novartis: Membership on an entity's Board of Directors or advisory committees. Stone:Otsuka: Consultancy; Jazz: Consultancy; Cornerstone: Consultancy; Fujifilm: Consultancy; Arog: Consultancy, Research Funding; Pfizer: Consultancy; Sumitomo: Consultancy; Novartis: Consultancy, Research Funding; Ono: Consultancy; Orsenix: Consultancy; Merck: Consultancy; Argenx: Other: Data and Safety Monitoring Board; AbbVie: Consultancy; Agios: Consultancy, Research Funding; Amgen: Consultancy; Astellas: Consultancy; Celgene: Consultancy, Other: Data and Safety Monitoring Board, Steering Committee. Thiede:AgenDix: Other: Ownership; Novartis: Honoraria, Research Funding. Döhner:AROG Pharmaceuticals: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; AROG Pharmaceuticals: Research Funding; Pfizer: Research Funding; Bristol Myers Squibb: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Celator: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Bristol Myers Squibb: Research Funding; Sunesis: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Astex Pharmaceuticals: Consultancy, Honoraria; Astex Pharmaceuticals: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Jazz: Consultancy, Honoraria; Pfizer: Research Funding; Seattle Genetics: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Agios: Consultancy, Honoraria; Celator: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Agios: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Jazz: Consultancy, Honoraria.

Description: Background: Genomically instable (GI) chronic lymphocytic leukemia (CLL) is characterized by frequent alterations in DNA-damage response (DDR) genes (e.g. TP53,ATM) and related pathways. Conversely, pathogenic networks in CLL cases which maintain genomic integrity and operate with a functional DDR remain incompletely described. Methods: Molecular profiling was conducted on CD19 sorted samples derived from patients registered on the CLL8 study (1st-line, FC vs. FCR) for gene expression (GEP)(n=337, Exon 1.0 ST arrays, Affymetrix), copy number aberrations (CNAs) (n=309, SNP Arrays 6.0, Affymetrix) and mutation analyses/signature projections (n=171, whole exome sequencing, Illumina). FISH, IGHV and TP53 mutation analysis was conducted at trial enrolment. Results: Unsupervised consensus clustering (k=2-6) on variably expressed genes (SD〉0.5) was used for class discovery. Two small, but highly differentiated clusters were identified, characterized through NRIP1 and EBF1/tri12. GSEA also segregated the remaining samples into four major clusters showing signatures of inflammation (I) and without inflammation (NI). These clusters were further segregated into GI-CLL clusters with increased "DNA-repair" or clusters with "epithelial-mesenchymal transition"-like signatures (EMT-L). Variability for del(17p)/TP53 mutation was found across clusters (p