Abstract: Background In newly diagnosed acute myeloid leukemia (AML), the general recommendation is to start treatment immediately after the diagnosis has been made. This paradigm is based both on the observation that untreated acute leukemia has a poor prognosis and on retrospective analyses demonstrating a shorter survival in younger AML patients (pts) in whom treatment was delayed by more than 5 days (Sekeres et al., 2009). A more recent single-center analysis came to a different conclusion, showing no prognostic effect for the time from diagnosis to treatment (TDT; Bertoli et al., 2013). We explored the relationship between TDT and prognosis on a large set of real-world data from the AML registry of the Study Alliance Leukemia (SAL) and compared it to the published cohorts. Methods The SAL runs a transregional AML registry in 46 treatment centers across Germany (NCT03188874). All registered patients with an intensive induction treatment, a minimum follow-up time of 12 months and no acute promyelocytic leukemia were selected (n=2,200). Treatment start was defined by the first day of cytarabine, whereas single agent hydroxyurea (HU) was labeled as pretreatment. We analyzed the influence of TDT on complete remission (CR), early death (ED) and overall survival (OS) in univariable analyses for each day of treatment delay, in groups of 0-5, 6-10, 11-15 and & gt;15 days of TDT, and by using the restricted cubic spline (RCS) method for data modelling. In order to adjust for the influence of established prognostic variables on the outcomes, we used multivariable regression models and propensity score weighting. The influence of HU pretreatment on outcomes was investigated by introducing an interaction term between TDT and the presence of HU pretreatment. Results The median age was 59 years (y) (IQR 50-68), the proportion of pts with favorable, intermediate and adverse genetic risk according to ELN was 27%, 53%, and 20%; & gt;95% of pts received induction treatment with standard 7+3. HU pretreatment was administered in 4% of pts. The median TDT was 3 days (IQR 2-6). Descriptive statistics after grouping of pts showed the highest median age and the lowest proportion of NPM1 mutated and favorable risk in the TDT group 11-15. Of all pts, 79% achieved a CR/CRi; unadjusted CR rates for the patient groups with TDT of 0-5, 6-10, 11-15 and & gt;15 days were 80%, 77%, 74% and 76%, respectively (p=0.317). In multivariable analysis accounting for the influence of ELN risk, age, WBC, LDH, de novo versus secondary AML and ECOG, the OR for each additional day of TDT was 0.99 (95%-CI, 0.97-1.00; p=0.124). Four percent of pts died within the first 30 days from treatment start. The respective rates in the four TDT categories were 4.0%, 3.8%, 5.1% and 4.1% (p=0.960). In multivariable analysis, the OR for TDT was 1.01 (95%-CI, 0.98-1.05; p=0.549). After a median follow-up of 40 months, the 2-y OS of all pts was 51%. The unadjusted 2-y OS rates stratified by TDT of 0-5, 6-10, 11-15, & gt;15 days were 52, 49, 46, and 51% (see Table 1 and Figure 1). The hazard ratio (HR) for each day of treatment delay was 1.00 (95%-CI; 0.99-1.01; p=0.317). In multivariable Cox regression analysis, the HR for TDT as continuous variable was 1.00 (95%-CI, 0.99-1.01; p=0.689). When OS was analyzed separately stratified for age ≤60 and & gt;60 ys and for high versus lower initial WBC defined by a threshold of 50 x 109/L, no significant differences between TDT groups were observed. Multivariable models using TDT as a grouped variable or with RCS did not provide evidence for a significant influence of TDT on outcomes. Propensity score matching of pts in the four TDT groups did not reveal an influence on outcomes. The use of HU was not associated with CR, ED nor OS. Conclusion Our study on 2,200 newly diagnosed registry pts receiving consistent intensive induction with standard-dose cytarabine plus daunorubicin (7+3) suggests that TDT is not related to response or survival, neither in younger nor in older pts. Despite multivariable analyses, a bias towards longer TDT intervals in pts judged to be clinically stable by the treating physician cannot be excluded entirely. As treatment stratification in intensive first-line treatment of AML evolves, the TDT data suggests that it may be a safe and reasonable approach to wait for genetic and other laboratory test results in order to assign clinically stable pts to the best available treatment option before the start of intensive treatment. Disclosures Krämer: Daiichi-Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Research Funding; BMS: Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Hänel:Roche: Honoraria; Amgen: Honoraria; Celgene: Other: advisory board; Novartis: Honoraria; Takeda: Other: advisory board. Jost:Daiichi: Honoraria; Sanofi: Honoraria; Gilead: Other: travel grants; Jazz Pharmaceuticals: Honoraria. Brümmendorf:Merck: Consultancy; Janssen: Consultancy; Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; University Hospital of the RWTH Aachen: Employment; Ariad: Consultancy. Krause:Siemens: Research Funding; Takeda: Honoraria; MSD: Honoraria; Gilead: Other: travel; Celgene Corporation: Other: Travel. Scholl:Novartis: Other: Project funding; Pfizer: Other: Advisory boards; Gilead: Other: Project funding; Daiichi Sankyo: Other: Advisory boards; AbbVie: Other: Advisory boards. Hochhaus:Pfizer: Research Funding; Novartis: Research Funding; BMS: Research Funding; Incyte: Research Funding; MSD: Research Funding. Kiani:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Middeke:Sanofi: Research Funding, Speakers Bureau; Roche: Speakers Bureau; AbbVie: Consultancy, Speakers Bureau; Gilead: Consultancy; Janssen: Consultancy, Speakers Bureau; MSD: Consultancy. Thiede:AgenDix GmbH: Employment, Equity Ownership; Novartis: Research Funding, Speakers Bureau; Bayer: Research Funding; Daiichi-Sankyo: Speakers Bureau. Stoelzel:JAZZ Pharmaceuticals: Consultancy; Neovii: Other: Travel funding; Shire: Consultancy, Other: Travel funding. Platzbecker:Celgene: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding.

Abstract: Background: Monitoring of measurable residual disease (MRD) in patients (pts) with advanced myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML) who achieve complete remission (CR) can predict hematological relapse. Recently published data from the first cohort of the RELAZA2-trial have shown that pre-emptive therapy with azacitidine (AZA) can prevent or substantially delay an overt relapse in MRD-positive pts with MDS or AML (Platzbecker et al. Lancet Oncol. 2018). Aims: To evaluate outcome of the entire patient cohort of the RELAZA2-trial and determine whether MRD-guided pre-emptive AZA treatment could prevent relapse in molecularly defined cohorts. Methods: Between 12/2011 and 07/2018 380 pts with advanced MDS or AML, who had achieved CR after conventional chemotherapy or allogeneic hematopoietic stem-cell transplantation (allo-HCT) were prospectively screened for MRD in monthly intervals either in bone marrow (BM) or peripheral blood (PB). A total of 94 pts (AML, n=83; MDS, n=11) became MRD positive during 24 months from baseline by either quantitative PCR (qPCR) or analysis of CD34+ donor-chimerism and entered the treatment phase. Preemptive MRD-triggered treatment consisted of AZA 75 mg/m2 per day subcutaneously on days 1-7 of a 29-day cycle for up to 24 cycles. After six cycles, MRD status was reassessed and pts with MRD negativity were eligible for treatment de-escalation. Primary endpoint was relapse-free survival (RFS) six months after start of pre-emptive treatment. For mutational analysis next generation sequencing (NGS) with a panel of 54 genes was performed (Illumina Trusight Myeloid). Results: Median age was 60 yrs (range: 22-80 yrs); 52 (55%) of the pts were female. Prior therapy consisted of chemotherapy in 42 (45%) and allo-HCT in 52 (55%) of the pts. Cytogenetics could be analyzed in 93 (99%) of the 94 pts. Risk categorization according to ELN 2017 was favorable in 30 (37%), intermediate in 31 (38%) and adverse in 21 (26%) of the AML pts, respectively. Type of MDS was advanced in all 11 pts and all were previously transplanted. Fifty-two (61%) of 85 pts with available NPM1 status were positive. NGS on 64 (68%) pts with available DNA at the time of first diagnosis revealed additional mutations in DNMT3A (n=25), TET2 (n=15), FLT3-ITD (n=12), IDH1 (n=9), FLT3-TKD (n=8), ASXL1, NRAS, TP53 (n=7, each), IDH2 (n=6), PTPN11, WT1 (n=5, each), GATA2, U2AF1 (n=4, each), CBL (n=3), CEBPA, CSFR3, CUX1, EZH2, KIT, RAD21, RUNX1, SF3B, STAG2, ZRSR2 (n=2, each), and KRAS (n=1). MRD data were correlated with outcome in 45 pts for NPM1, in 3 for RUNX1-RUNX1T1, whereas CD34-donor-chimerism was analyzed in 39 pts (missing, n=7). There was a significant faster and deeper decline of MRD in PB as compared to BM (P=0.03). The same held true with regard to the increase of donor-chimerism, which was achieved faster in PB as compared to BM (P=0.05). Secondary molecular abnormalities (MAs) had no impact on MRD response as measured by qPCR, which was also true if MAs were categorized functionally. Similarly, additional chromosomal abnormalities had no impact on MRD response in both MRD methods. However, in pts with measurement of donor-chimerism ASXL1 mutations were a negative factor for MRD response (P & lt;0.001). At hematological relapse, only 1 (2%) of 45 pts with NPM1 measurement was not congruently MRD positive. Six months after start of MRD-guided therapy, 56 (60%) of 94 pts were still in CR while a total of 38 pts (40%) developed a hematological relapse after median of 3 AZA cycles. 38 (40%) pts responded with either a decline of MRD below a predefined threshold (increasing donor-chimerism to ≥80% or PCR MRD & lt;1%), while a stabilization in the absence of relapse was achieved in 18 (19%) pts. Overall response rate was not statistically different between pts with (63%) or without (55%) antecedent allo-HCT (P=0.5). RFS rate at 6 months was 60% (56/94 pts). With a median follow-up of 9 months after start of MRD-guided pre-emptive treatment 12-months overall and progression-free survival rates were 94% and 44%, respectively. Conclusions: AZA as a pre-emptive therapy was effective in delaying hematological relapse of advanced MDS or AML pts, regardless of the underlying genetic signature. Based on these encouraging results, intensifying treatment with AZA in combination with pembrolizumab is currently investigated as MRD-guided treatment in NPM1 positive AML (PEMAZA; ClinicalTrials.gov Identifier: NCT03769532). Disclosures Wolf: Celgene: Honoraria, Research Funding. Bug:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Hexal: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Eurocept: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Jazz: Honoraria; Neovii: Other: Travel; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Sanofi: Other: Travel. Götze:Celgene: Research Funding. Stelljes:Amgen: Consultancy, Speakers Bureau; Pfizer: Consultancy, Honoraria, Research Funding, Speakers Bureau. Subklewe:Celgene: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Seattle Genetics: Research Funding; Morphosys: Research Funding; Janssen: Consultancy; AMGEN: Consultancy, Honoraria, Research Funding; Roche AG: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Gilead Sciences: Consultancy, Honoraria, Research Funding. Haenel:Amgen, Novartis, Roche, Celgene, Takeda, Bayer: Honoraria. Rollig:Amgen, Astellas, BMS, Daiichi Sankyo, Janssen, Roche: Consultancy; Abbvie, Novartis, Pfizer: Consultancy, Research Funding. Müller-Tidow:Pfizer: Research Funding, Speakers Bureau; Daiichi Sankyo: Research Funding; BiolineRx: Research Funding; Janssen-Cilag GmbH: Speakers Bureau. Platzbecker:Novartis: Consultancy, Honoraria, Research Funding; Amgen: Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Geron: Consultancy, Honoraria. Thiede:AgenDix GmbH: Other: Co-owner and CEO. OffLabel Disclosure: Off-label: treatment with azacitidine to prevent or substantially delay an overt relapse in MRD-positive patients with MDS or AML

Abstract: Patients with acute myeloid leukemia (AML) and abnormalities (abnl) of the short arm of chromosome 17 (17p) are considered to be at high risk of treatment failure after conventional chemotherapy. Small studies have suggested that this abnormality may portend a poor prognosis even after allogeneic hematopoietic stem cell transplantation (HSCT). The aim of this study was to assess the prognostic role of abnl(17p) in a larger cohort of patients with AML undergoing allogeneic HSCT, and to analyse the impact of disease status, conditioning regimen, and type of abnormality. Here, we present data on the outcome of 201 patients with abnl(17p) AML transplanted since 2000. Patients and Methods We performed a retrospective cohort analysis based on study-registries from two AML groups, HOVON and SAL, and transplant-registries of the Fred Hutchinson Cancer Research Center (FHCRC) and the German Cooperative Transplant Study Group (GCTSG). Inclusion criteria were AML diagnosed according to the current WHO criteria with 17p abnormalities and a first HSCT between January, 1, 2000 and January, 1, 2011. Overall survival (OS), event-free survival (EFS), cumulative incidence of relapse (CIR) and non-relapse-mortality (NRM) after HSCT are reported for the whole cohortand for patients receiving HSCT in first complete remission (CR1). We tested for center effects (FHCRC, HOVON, SAL, GCTSG) in a multivariate Cox regression model. Results Data from 201 patients with full information on the karyotype were analysed. The median age was 54 years with a range from 2 years to 75 years. Five patients were younger than 18 years. Sixty-one percent of the patients suffered from de novo AML, while 26% had secondary AML and 11% therapy-related myeloid neoplasm. Complex and monosomal karyotypes were present in 90% and 77% of patients, respectively. Eighty-four patients (42%) were in CR1 at the time of HSCT. Seventy patients (35%) were treated with standard myeloablative conditioning (MAC) regimens while the remaining patients received reduced intensity conditioning (RIC). Donors were matched siblings in 34%, matched unrelated donors in 43% and partially matched or mismatched unrelated donors in 18% of the patients. Eight patients (4%) had a haploidentical donor. At the time of analysis 30 patients were alive with a median follow-up of 30 months (range 1 to 121 months). At three years, the probabilities of OS and EFS were 15% (95% CI, 10% to 20%) and 12% (95% CI, 7% to 16%), respectively, whereas the CIR was 49%. For patients transplanted in CR1 the probability of OS at three years was 22% (95% CI, 13% to 32%) compared to 9% (95% CI, 3% to 15%) for those with advanced disease (p= 〈 .001). The main cause of treatment failure was relapse. The CIR at three years was 57% in patients who were transplanted in CR1 compared to 42% in patients with more advanced disease (p=.0912). Notably, 70% of the observed relapses occurred within the first six months after HSCT. NRM was also high within the first six months, mainly among patients with advanced disease (40% NRM in advanced stages compared to 14% in CR1; p= 〈 .001). In multivariate analysis only age (HR=1.02; p=.01) and disease status (HR=0.52; p=.007) had a significant influence on OS. No significant differences in outcomes were observed between the different types of abnormalities regarding OS, EFS, CIR and NRM, but patients with a monosomal karyotype had worse outcome compared to patients with a non-MK karyotype (3-year OS 11% versus 29%, p=.003). The incidence of grade II to IV acute GvHD up to day 100 was 32% while grade III to IV occurred in 11% of the patients. Due to the high frequency of competing events (death or relapse before onset of GvHD) the cumulative incidence for chronic GvHD at one year was very low with 8%. Conclusion Patients with abnl(17p) AML have a poor outcome after HSCT. The observation of better outcome in patients with less advanced disease stages and without MK argues against primary resistance to allogeneic immune effects of 17p abnormalities. While transplantation in CR1 may still be considered the treatment of choice due to the lack of more promising alternatives, novel strategies to prevent relapse are highly warranted for this group of patients. For patients with abnl(17p) AML in more advanced stages experimental approaches should be considered. Disclosures: No relevant conflicts of interest to declare.

Abstract: Tandem-duplication mutations of the UBTF gene ( UBTF -TDs) coding for the upstream binding transcription factor have recently been described in pediatric patients with acute myeloid leukemia (AML) and were found to be associated with particular genetics (trisomy 8 (+8), FLT3 -internal tandem duplications ( FLT3 -ITD), WT1 -mutations) and inferior outcome. Due to limited knowledge on UBTF- TDs in adult AML, we screened 4247 newly diagnosed adult AML and higher-risk myelodysplastic syndrome (MDS) patients using high-resolution fragment analysis. UBTF -TDs were overall rare ( n  = 52/4247; 1.2%), but significantly enriched in younger patients (median age 41 years) and associated with MDS-related morphology as well as significantly lower hemoglobin and platelet levels. Patients with UBTF -TDs had significantly higher rates of +8 (34% vs. 9%), WT1 (52% vs. 7%) and FLT3 -ITD (50% vs. 20.8%) co-mutations, whereas UBTF -TDs were mutually exclusive with several class-defining lesions such as mutant NPM1 , in-frame CEBPA bZIP mutations as well as t(8;21). Based on the high-variant allele frequency found and the fact that all relapsed patients analyzed ( n  = 5) retained the UBTF -TD mutation, UBTF -TDs represent early clonal events and are stable over the disease course. In univariate analysis, UBTF -TDs did not represent a significant factor for overall or relapse-free survival in the entire cohort. However, in patients under 50 years of age, who represent the majority of UBTF -mutant patients, UBTF -TDs were an independent prognostic factor for inferior event-free (EFS), relapse-free (RFS) and overall survival (OS), which was confirmed by multivariable analyses including established risk factors such as age and ELN2022 genetic risk groups (EFS [HR: 2.20; 95% CI 1.52–3.17, p   〈  0.001], RFS [HR: 1.59; 95% CI 1.02–2.46, p  = 0.039] and OS [HR: 1.64; 95% CI 1.08–2.49, p  = 0.020]). In summary, UBTF -TDs appear to represent a novel class-defining lesion not only in pediatric AML but also younger adults and are associated with myelodysplasia and inferior outcome in these patients.

Abstract: Acute myeloid leukemia (AML) is characterized by recurrent genetic events. The BCL6 corepressor (BCOR) and its homolog, the BCL6 corepressor-like 1 (BCORL1), have been reported to be rare but recurrent mutations in AML. Previously, smaller studies have reported conflicting results regarding impacts on outcomes. Here, we retrospectively analyzed a large cohort of 1529 patients with newly diagnosed and intensively treated AML. BCOR and BCORL1 mutations were found in 71 (4.6%) and 53 patients (3.5%), respectively. Frequently co-mutated genes were DNTM3A, TET2 and RUNX1. Mutated BCORL1 and loss-of-function mutations of BCOR were significantly more common in the ELN2017 intermediate-risk group. Patients harboring loss-of-function mutations of BCOR had a significantly reduced median event-free survival (HR = 1.464 (95%-Confidence Interval (CI): 1.005–2.134), p = 0.047), relapse-free survival (HR = 1.904 (95%-CI: 1.163–3.117), p = 0.01), and trend for reduced overall survival (HR = 1.495 (95%-CI: 0.990–2.258), p = 0.056) in multivariable analysis. Our study establishes a novel role for loss-of-function mutations of BCOR regarding risk stratification in AML, which may influence treatment allocation.

Abstract: The fusion genes CBFB / MYH11 and RUNX1 / RUNX1T1 block differentiation through disruption of the core binding factor (CBF) complex and are found in 10–15% of adult de novo acute myeloid leukemia (AML) cases. This AML subtype is associated with a favorable prognosis; however, nearly half of CBF-rearranged patients cannot be cured with chemotherapy. This divergent outcome might be due to additional mutations, whose spectrum and prognostic relevance remains hardly defined. Here, we identify nonsilent mutations, which may collaborate with CBF-rearrangements during leukemogenesis by targeted sequencing of 129 genes in 292 adult CBF leukemia patients, and thus provide a comprehensive overview of the mutational spectrum (‘mutatome’) in CBF leukemia. Thereby, we detected fundamental differences between CBFB/MYH11 - and RUNX1/RUNX1T1 -rearranged patients with ASXL2 , JAK2, JAK3, RAD21 , TET2, and ZBTB7A being strongly correlated with the latter subgroup. We found prognostic relevance of mutations in genes previously known to be AML-associated such as KIT , SMC1A, and DHX15 and identified novel, recurrent mutations in NFE2 (3%), MN1 (4%), HERC1 (3%), and ZFHX4 (5%). Furthermore, age 〉 60 years, nonprimary AML and loss of the Y-chromosomes are important predictors of survival. These findings are important for refinement of treatment stratification and development of targeted therapy approaches in CBF leukemia.

Abstract: Extramedullary manifestations (EM) are rare in acute myeloid leukemia (AML) and their impact on clinical outcomes is controversially discussed. Methods We retrospectively analyzed a large multi-center cohort of 1583 newly diagnosed AML patients, of whom 225 (14.21%) had EM. Results AML patients with EM presented with significantly higher counts of white blood cells ( p   〈  0.0001), peripheral blood blasts ( p   〈  0.0001), bone marrow blasts ( p  = 0.019), and LDH ( p   〈  0.0001). Regarding molecular genetics, EM AML was associated with mutations of NPM1 (OR: 1.66, p   〈  0.001), FLT3 -ITD (OR: 1.72, p   〈  0.001) and PTPN11 (OR: 2.46, p   〈  0.001). With regard to clinical outcomes, EM AML patients were less likely to achieve complete remissions (OR: 0.62, p  = 0.004), and had a higher early death rate (OR: 2.23, p  = 0.003). Multivariable analysis revealed EM as an independent risk factor for reduced overall survival (hazard ratio [HR]: 1.43, p   〈  0.001), however, for patients who received allogeneic hematopoietic cell transplantation (HCT) survival did not differ. For patients bearing EM AML, multivariable analysis unveiled mutated TP53 and IKZF1 as independent risk factors for reduced event-free (HR: 4.45, p   〈  0.001, and HR: 2.05, p  = 0.044, respectively) and overall survival (HR: 2.48, p  = 0.026, and HR: 2.63, p  = 0.008, respectively). Conclusion Our analysis represents one of the largest cohorts of EM AML and establishes key molecular markers linked to EM, providing new evidence that EM is associated with adverse risk in AML and may warrant allogeneic HCT in eligible patients with EM.

Abstract: In fit patients with newly diagnosed acute myeloid leukemia (AML), immediate treatment start is recommended due to the poor prognosis of untreated acute leukemia. We explored the relationship between time from diagnosis to treatment start (TDT) and prognosis in a large real-world data set from the German Study Alliance Leukemia–Acute Myeloid Leukemia (SAL-AML) registry. All registered non–acute promyelocytic leukemia patients with intensive induction treatment and a minimum 12 months of follow-up were selected (n = 2263). We analyzed influence of TDT on remission, early death, and overall survival (OS) in univariable analyses for each day of treatment delay, in groups of 0 to 5, 6 to 10, 11 to 15, and & gt;15 days of TDT, adjusted for influence of established prognostic variables on outcomes. Median TDT was 3 days (interquartile range, 2-7). Unadjusted 2-year OS rates, stratified by TDT of 0 to 5, 6 to 10, 11 to 15, and & gt;15 days, were 51%, 48%, 44%, and 50% (P = .211). In multivariable Cox regression analysis accounting for established prognostic variables, the TDT hazard ratio as a continuous variable was 1.00 (P = .617). In OS analyses, separately stratified for age ≤60 and & gt;60 years and for high vs lower initial white blood cell count, no significant differences between TDT groups were observed. Our study suggests that TDT is not related to survival. As stratification in intensive first-line AML treatment evolves, TDT data suggest that it may be a feasible approach to wait for genetic and other laboratory test results so that clinically stable patients are assigned the best available treatment option. This trial was registered at www.clinicaltrials.gov as #NCT03188874.