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Higher doses of cytarabine appear to improve long-term outcome in acute myeloid leukemia (AML), in particular for younger patients. To this end, the optimal dosage of single agent cytarabine in consolidation therapy remains elusive. Here, we assessed the impact of different dosages of cytarabine consolidation after 7 + 3 induction on outcome in a large real-world data set from the German Study Alliance Leukemia-Acute Myeloid Leukemia (SAL-AML) registry. Patients below 65 years of age, registered between April 2005 and September 2020, who attained complete remission after intensive induction and received at least one consolidation cycle with intermediate (IDAC) or high dose cytarabine (HiDAC) were selected. To account for differences in patient and disease characteristics between both groups, the average treatment effect was estimated by propensity score weighting. Six-hundred-forty-two patients received HiDAC consolidation with median dosage of median 17.6 (IQR, 16.5–18.0) g/m² for a median number of 3 cycles (IQR, 2–3), whereas 178 patients received IDAC consolidation with 5.9 (IQR, 5.7–8.6) g/m² for a median of 2 cycles (IQR, 1–3). Both groups differed significantly in some important characteristics (age, sex, cytogenetic risk group, ECOG performance status, disease status, HCT-CI, number of induction cycles). After propensity score weighting for differences in patient and disease characteristics, relapse-free survival after 2 years was comparable between HiDAC-treated (55.3%) and IDAC-treated (55.6%) patients. Moreover, no significant differences in overall survival were observed after 2 years (84.7 vs. 80.6%). Notably, more patients treated with IDAC received allogeneic hematopoietic cell transplantation in first remission (37.6 vs. 19.8%, p

Acute myeloid leukemia (AML) is characterized by a high relapse rate and dismal long-term overall survival which is related to persistence of leukemia-initiating cells in their niche. Different animal models of myeloid malignancies reveal how neoplastic cells alter the structural and functional characteristics of the hematopoietic stem cell niche to reinforce malignancy. Understanding and disruption of the microenvironmental interactions with AML cells are a vital need. Malignant niches frequently go along with inflammatory responses, but their impact on cancerogenesis often remains unexplored. Here, we uncovered an aberrant production of inflammatory cytokines in untreated AML bone marrow that was proved to promote the proliferation of leukemia cells. This inflammatory response induced an activation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway in AML blasts as well as bone marrow stromal cells that also fostered leukemia proliferation. Inhibition of JAK/STAT signaling using the selective JAK1/2 inhibitor ruxolitinib resulted in significant antileukemic activity in AML in vitro which is mediated through both cell-autonomous and microenvironment-mediated mechanisms. However, in a xenograft transplantation model, monotherapy with ruxolitinib did not achieve substantial antileukemic activity, possibly suggesting a complementary function of JAK1/2 inhibition in AML.

Background Valid prognostic tools are needed to guide risk-adjusted treatment approaches in patients with diffuse large B-cell lymphoma (DLBCL). Methods We assessed total metabolic tumor volume (TMTV) and standardized uptake value (SUV)-based interim positron emission tomography (iPET) response in 510 patients with DLBCL participating in the positron emission tomography-guided therapy of aggressive non-Hodgkin lymphomas (PETAL) trial (NCT00554164). TMTV was analyzed with a relative (SUV41max) and a fixed thresholding method (SUV4), and iPET was evaluated using the ΔSUVmax procedure. We determined associations between TMTV and international prognostic index (IPI) factors using Welch's t-test, investigated effects of TMTV, iPET response, and the IPI factors on time to progression (TTP), progression-free survival (PFS), and overall survival (OS) by Cox regression, and estimated the outcome using Kaplan–Meier curves. Findings TMTV was associated with all IPI factors except age. Irrespective of the thresholding method used, TMTV and iPET response were correlated with TTP, PFS, and OS, and remained the only independent outcome predictors in Cox regression analysis. By dichotomizing TMTV (cut-off: 328 cm³ by SUV41max) and iPET response (cut-off: 66% SUVmax reduction), we defined three groups at different risk of treatment failure (low [57.1% of patients]: low TMTV/good iPET response; intermediate [37.8%]: high TMTV/good iPET response or low TMTV/poor iPET response; and high [5.1%]: high TMTV/poor iPET response), with corresponding 2-year probabilities of 93.8% vs. 67.3% vs. 38.5% for TTP, 90.9% vs. 62.5% vs. 29.9% for PFS, and 95.5% vs. 77.4% vs. 37.1% for OS. Interpretation The PET-based risk model proposed may help identify patients who may benefit from treatment modifications or novel approaches.

Background: Trisomy 4 is a recurrent but rare cytogenetic abnormality reported in patients with acute myeloid leukemia (AML). The prognostic significance of this abnormality in AML patients is not clear. Prognosis of AML patients with trisomy 4 seems to be poor as compared to that of patients with intermediate-risk cytogenetics. Allogeneic hematopoietic stem cell transplantation (allo-HCT) may improve survival if applied early in first complete remission (CR). However, neither prospective clinical nor larger retrospective cohort studies are available to support these results from small series. Aims: To characterize AML patients with trisomy 4 and compare outcomes according to different treatment strategies. Methods: We retrospectively studied 123 AML patients with trisomy 4 (median age at diagnosis, 58 years; range, 16-76 years) treated between 2000 and 2019 within 2 large study groups. Standard statistical methods were applied. Results: Median white blood cell count at diagnosis was 4.8/nl (range, 0.4-255/nl) and platelets 46/nl (range, 2-330/nl). Type of AML was de novo in 97 (79%), secondary after myelodysplastic syndrome/myeloproliferative neoplasm in 18 (15%), and therapy-related in 8 (6%) patients. Sixty-two (50%) patients were female. Cytogenetic analysis revealed trisomy 4 as the sole abnormality in 28 (23%), additional abnormalities in 95 (77%) patients, most frequently ≥3 (n=66) abnormalities, trisomy 8 (n=41), karyotypes characterized by trisomies only (n=21) and t(8;21) or inv(16) (CBF; n=10). A total of 98 patients (80%) had NPM1 and FLT3-ITD mutation testing. Of those, 21 (21%) and 15 (15%) harbored NPM1 and FLT3-ITD mutations. Only 2 (3%) of 72 patients were CEBPA double mutated. Data on response to intensive anthracycline-based induction therapy were available in 117 patients. Early death rate was 5% (n=6). CR was achieved in 68% (n=79) with 22 (19%) requiring an intensive salvage treatment cycle. Notably, patients with trisomy 4 as sole abnormality had a CR rate of 89% (n=25/28). There was no difference in the CR rate in FLT3-ITD positive (n=10/15) as compared to FLT3 wild type (n=56/83) patients (67% each, P=0.99). Univariable analysis revealed trisomy 4 as sole abnormality (OR, 5.76; P=0.007) and NPM1 (OR, 12.08; P=0.02) as favorable factors. An allo-HCT was performed in 40 (34%) patients, of whom 19 patients were transplanted in first CR after induction therapy. Nine patients achieved CR after salvage chemotherapy and went on to allo-HCT; another 12 patients received allo-HCT with active disease. Type of donor was matched-related in 8, matched-unrelated in 30, and unknown in 2 of the 40 patients, respectively. Median follow-up of the intensively treated cohort was 73 months (95%-CI, 36-91 months). Five-year overall survival (OS) and relapse-free survival (RFS) were 31% (95%-CI, 23-42%) and 27% (95%-CI, 18-42%). OS rates were significantly higher in patients with CBF leukemia or patients with trisomy 4 as compared to all other abnormalities (Figure 1; P Conclusions: Clinically, patients with trisomy 4 are very heterogeneous in particular with respect to cytogenetic and molecular abnormalities. In our cohort, patients with trisomy 4 as a sole abnormality had a high CR rate and favorable clinical outcome. In the total cohort, allo-HCT did not improve RFS. Figure 1 Figure 1. Disclosures Krause: Siemens: Research Funding; Takeda: Honoraria; Pfizer: Honoraria; art-tempi: Honoraria; Kosmas: Honoraria; Gilead: Other: travel support; Abbvie: Other: travel support. Schliemann: Philogen S.p.A.: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Other: travel grants; Astellas: Consultancy; AstraZeneca: Consultancy; Boehringer-Ingelheim: Research Funding; BMS: Consultancy, Other: travel grants; Jazz Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy; Roche: Consultancy; Pfizer: Consultancy. Haenel: Takeda: Consultancy, Honoraria; Bayer Vital: Honoraria; Jazz: Consultancy, Honoraria; GSK: Consultancy; Roche: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy; Celgene: Consultancy, Honoraria. Crysandt: Incyte: Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees. Fransecky: Medac: Honoraria; Amgen: Honoraria; Abbvie: Honoraria, Research Funding; Novartis: Honoraria; Takeda: Honoraria. Martinez-Lopez: Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Einsele: Janssen, Celgene/BMS, Amgen, GSK, Sanofi: Consultancy, Honoraria, Research Funding. Platzbecker: AbbVie: Honoraria; Celgene/BMS: Honoraria; Janssen: Honoraria; Novartis: Honoraria; Geron: Honoraria; Takeda: Honoraria. Baldus: Novartis: Honoraria; Amgen: Honoraria; Celgene/BMS: Honoraria; Jazz: Honoraria. Müller-Tidow: Pfizer: Research Funding; Janssen: Consultancy, Research Funding; Bioline: Research Funding. Levis: Astellas and FujiFilm: Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Jazz: Consultancy, Honoraria; Amgen, Astellas Pharma, Daiichi-Sankyo, FujiFilm, and Menarini: Honoraria; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria; Takeda: Honoraria. Montesinos: Stemline/Menarini: Consultancy; Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Forma Therapeutics: Consultancy; Glycomimetics: Consultancy; Tolero Pharmaceutical: Consultancy; Agios: Consultancy; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astellas Pharma, Inc.: Consultancy, Honoraria, Other: Advisory board, Research Funding, Speakers Bureau. Röllig: Roche: Honoraria, Research Funding; Bristol-Meyer-Squibb: Honoraria, Research Funding; Janssen: Honoraria; Jazz: Honoraria; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Amgen: Honoraria; AbbVie: Honoraria, Research Funding. Schlenk: Novartis: Honoraria; Pfizer: Honoraria, Research Funding, Speakers Bureau; Hexal: Honoraria; Neovio Biotech: Honoraria; Daiichi Sankyo: Honoraria, Research Funding; Celgene: Honoraria; Astellas: Honoraria, Research Funding, Speakers Bureau; Abbvie: Honoraria; Agios: Honoraria; Roche: Honoraria, Research Funding; AstraZeneca: Research Funding; Boehringer Ingelheim: Research Funding.

Targeting the interaction between leukemic cells and the microenvironment is an appealing approach to enhance the therapeutic efficacy in acute myeloid leukemia (AML). AML infiltration induces a significant release of inflammatory cytokines in the human bone marrow niche which accelerates leukemogenesis. As the transmembrane glycoprotein CD38 has been shown to regulate cytokine release, we assessed the anti-leukemic potential of CD38 inhibition in AML. CD38 expression in AML cells proved to depend on microenvironmental cues and could be significantly enforced through addition of tretinoin. In fact, the anti-CD38 antibody daratumumab showed significant cytostatic efficacy in a 3D in vitro triple-culture model of AML, but with modest cell-autonomous cytotoxic activity and independent of CD38 expression level. In line with a predominantly microenvironment-mediated activity of daratumumab in AML, CD38 inhibition significantly induced antibody-dependent phagocytosis and showed interference with AML cell trafficking in vivo in a xenograft transplantation model, but overall lacked robust anti-leukemic effects.

Background Double induction using two subsequent 7+3 regimens of cytarabine plus anthracycline is commonly performed in AML patients with an adequate performance status in order to maximize dose intensity upfront. However, for patients with a good early response at day 15 of first induction, there is no prospective randomized evidence on the necessity or value of a second induction cycle. Aims In order to answer the question if good responders of the first 7+3 induction could be spared a second induction cycle, we set up randomized-controlled SAL DaunoDouble trial. The study prospectively assesses the outcome of patients with a good early response with respect to the number of induction cycles (single versus double). We assumed non-inferiority of single induction in terms of complete remission (CR/CRi) rate, based on a margin of 7.5%. Here, we present the results of the planned interim analysis. Methods Patients (pts) 18-65 years with newly diagnosed AML, normal cardiac and organ function received a first induction cycle with seven days of cytarabine plus three days of daunorubicin ("7+3"). Response assessment in bone marrow was done on day 15 after the initiation of chemotherapy and confirmed by central review. A blast count Results Between 2014 and 2020, 624 evaluable pts were enrolled and received the first induction cycle with 7+3. A marrow blast clearance below 5% on day 15 was achieved in 298 pts (48%), providing eligibility for randomization. Of these patients, 150 were randomized into arm S and 148 into arm D, respectively. Median age was 52 years, 92% had de novo AML, NPM1 mutation was present in 53%, FLT3-ITD in 25% of pts. Favorable, intermediate and adverse risk (ELN 2017) were present in 56%, 34% and 10% of pts, respectively. CR/CRi rates at the end of induction were 86% after single induction and 85% after double induction. The CR/CRi rates in 224 pre-defined per-protocol pts were 88% versus 91%, resulting in a CR difference of 3% (95%-CI -0.047-0.111; p for non-inferiority test 0.145). After a median follow-up time of 24 months, RFS was slightly but not significantly lower after single induction with a 3-year RFS of 53% versus 64% (HR 1.4, p=0.125), whereas no differences were seen in 3-year OS, with a of rate of 74% versus 75% (HR 1.1, p=0.645) after single versus double induction. Conclusion The interim analysis results show that in good responders, the difference between CR rates after single versus double induction was even smaller than the predefined 7.5% margin, suggesting a trend for non-inferiority of single induction, although statistical significance was not reached. The trial continued recruitment. These findings suggest that in good responders, it may be safe to omit a second induction cycle if a second cycle poses a high risk. Figure. CR + CRi, RFS and OS after randomization to single versus double induction. Disclosures Alakel: Pfizer: Consultancy. Jost:Pfizer: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; JAZZ: Other: travel support; Celgene: Other: travel support. Novak:Roche: Consultancy; Janssen: Other: Travel expenses; Takeda: Consultancy; Amgen: Consultancy, Other: Travel expenses; Pfizer: Consultancy; Novartis: Consultancy. Krause:Takeda: Honoraria; Celgene: Other: Travel Support; MSD: Honoraria; Pfizer: Honoraria; Siemens: Research Funding; Gilead: Other: Travel Support. Held:Roche: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding; BMS: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding; MSD: Consultancy; Acrotech: Research Funding; Spectrum: Research Funding; Amgen: Research Funding. Platzbecker:AbbVie: Consultancy, Honoraria; Amgen: Honoraria, Research Funding; Geron: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria. Thiede:AgenDix GmbH: Other: Co-owner and CEO. Müller-Tidow:Daiichi Sankyo: Research Funding; Pfizer: Research Funding, Speakers Bureau; BiolineRx: Research Funding; Janssen-Cilag GmbH: Speakers Bureau.

Summary: In the prostate, stem and progenitor cell regenerative capacities have been ascribed to both basal and luminal epithelial cells. Here, we show that a rare subset of mesenchymal cells in the prostate are epithelial-primed Nestin-expressing cells (EPNECs) that can generate self-renewing prostate organoids with bipotential capacity. Upon transplantation, these EPNECs can form prostate gland tissue grafts at the clonal level. Lineage-tracing analyses show that cells marked by Nestin or NG2 transgenic mice contribute to prostate epithelium during organogenesis. In the adult, modest contributions in repeated rounds of regression and regeneration are observed, whereas prostate epithelial cells derived from Nestin/NG2-marked cells are dramatically increased after severe irradiation-induced organ damage. These results indicate that Nestin/NG2 expression marks a novel radioresistant prostate stem cell that is active during development and displays reserve stem cell activity for tissue maintenance. : In this article, Frenette and colleagues show that Nestin/NG2-expressing cells contribute to prostate epithelium during organogenesis and retain reserve stem cell activity during severe irradiation-induced tissue damage while epithelial-primed Nestin-expressing cells maintain bilineage epithelial differentiation potential in the unperturbed adult prostate. Keywords: prostate stem cell, Nestin, mesenchymal-to-epithelial transition

BackgroundOverall survival remains poor in older patients with acute myeloid leukemia (AML) with less than 10% being alive after five years. In recent studies, a significant improvement in event-free, relapse-free and overall survival was shown by adding gemtuzumab ozogamicin (GO), a humanized antibody-drug conjugate directed against CD33, to intensive induction therapy once or in a sequential dosing schedule. Glasdegib, the small-molecule inhibitor of smoothened (SMO), also showed improved overall survival in patients not eligible for intensive chemotherapy when combined with low-dose cytarabine compared to low-dose cytarabine alone. These findings warrant further investigations in the phase III GnG trial.Methods/DesignThis is a randomized phase III trial with measurable residual disease (MRD) after induction therapy and event-free survival (EFS) as primary endpoints. The two research questions are addressed in a 2 by 2 factorial design. Patients age 60 years and older are upfront randomized 1:1 in one of the two induction arms: GO administered to intensive induction therapy on days 1,4 and 7 versus GO administered once on day 1 (GO-147 versus GO-1), and double-blinded 1:1 in one of the subsequent treatment arms glasdegib vs. placebo as adjunct to consolidation therapy and as single-agent maintenance therapy for six months. Chemotherapy backbone for induction therapy consists of standard 7+3 schedule with cytarabine 200mg/m² continuously days 1 to 7, daunorubicin 60mg/m² days 1, 2 and 3 and high-dose cytarabine (1g/m², bi-daily, days 1,2,3) for consolidation therapy. Addressing two primary endpoints, MRD-negativity after induction therapy and event-free survival (EFS), 252 evaluable patients are needed to reject each of the two null hypotheses at a two-sided significance level of 2.5% with a power of at least 85%. ETHICS AND DISSEMINATION: Ethical approval and approvals from the local and federal competent authorities were granted. Trial results will be reported via peer-reviewed journals and presented at conferences and scientific meetings.TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT04093505; EudraCT Number: 2019-003913-32.TRIAL REGISTRATION DATE: October 30, 2018

Trials 22(1), 765 (2021). doi:10.1186/s13063-021-05703-w, Published by BioMed Central, London

Background Venetoclax (VEN)-based combination therapy with hypomethylating agents (HMA) has been approved for first-line treatment in patients ineligible for intensive treatment based on two randomized trials. There is some evidence for efficacy also in the in relapsed/ refractory setting (R/R), but comparative controlled data is lacking. Here, we report our experience of VEN-Azacitidine (AZA) in R/R AML salvage treatment and bridge to allogeneic cell transplantation (allo-HCT) in fit patients compared to historical data from the Study Alliance Leukemia (SAL) registry (ClinicalTrials.gov Identifier: NCT03188874). Design/Methods We analyzed all patients with R/R AML after initial intensive therapy, who started VEN-AZA salvage treatment at the University Hospital Heidelberg, between October 2018 and October 2020. Patients, who were bridged to allo-HCT were compared in a multivariable analysis to data of R/R AML patients from the SAL registry receiving an allo-HCT. Results: A total of 26 patients (median age 60 years, range 23 to 79) were included. All patients initially received intensive therapy, 16 patients (62%) had been refractory to intensive induction therapy with DA (daunorubicin, cytarabine) (11 patients)/ CPX-351 (2 patients) or to an intensive salvage therapy regime with HAM (2 patients)/ Cytarabin-Bortezomib (1 patient). Ten patients (38%) had morphologic (7 patients) or molecular relapse (3 patients) after intensive first line therapy. The distribution of AML according to WHO-2016 classification was n=10 recurrent genetic abnormalities (n= 7, mutated NPM1; n=1, biallelic CEBPA mutations; n=1, mutated RUNX1; n=1, CBFB-MYH11), n=10 AML with MRC, n=6 AML NOS. According to the 2017 ELN classification, 9 patients (34,5%) had low risk, 8 (31%) intermediate risk and 9 (34,5%) adverse risk disease. All patients received AZA 75mg/m² for 7 days combined with VEN 400mg/day after initial ramp up or a reduced dose of 100mg/day in case of co-medication with azoles in 28 days cycles. Best response was CR/CRi in 58% (n=15), PR in 23% (n=6) patients. Day 30-mortality was 0%, day 60-mortality was 4% (n=1). Allo-HCT was performed in 20 patients (77%). Pre-Allo-HCT remission status was CR/CRi in 11 (55%), PR in 4 (20%) patients and MLFS in 1 patient and 4 patients had active disease (n=3, relapse after achieving CR/CRi on VEN-AZA, n=1 refractory to VEN-AZA.). At the time of analysis 15 (75%) of the 20 bridged patients were alive and 11 (55%) are still in CR resulting in a median relapse-free survival in bridged patients of 406 days, whereas all patients not proceeding to allo-HCT died after a median of 139 days. In total, 63 patients with R/R AML were identified in the SAL-registry proceeding to allo-HCT with non VEN-based salvage attempt. Pre-Allo-HCT remission status was CR/CRi in 18 (28%), PR in 15 (24%), unknown in 13 patients (21%) and 17 (27%) patients had active disease (n=9 relapsed, n=8 refractory). Patients of the SAL registry were younger (median, 55 years; range, 22-75 years) and more patients were ELN-int (low risk, 32%, n=20; int, 52%, n=33, adv, 16%, n=10). Median follow-up in the VEN-AZA and the SAL cohorts were 1.4 years and 4.6 years, respectively. Cox-regression modeling of survival measured from the date of being refractory/relapsed revealed a non-significant effect of the cohorts favoring the VEN-AZA salvage therapy (HR, 0.87, p=0.73). However, stratified univariable survival analysis revealed in trend better survival (p=0.10) in the VEN-AZA compared to the SAL cohort with 77% (95%-CI, 62-95%) and 74% (95%-CI, 57-97%) as well as 84% (95%-CI, 76-94%) and 52% (95-CI, 41-68%) 1- and 2-years survival, respectively. Conclusion: Our data confirms the efficacy of VEN-AZA in patients with R/R AML and underlines its potential as an effective strategy for bridging to successful allo-HCT. Disclosures Unglaub: JazzPharma: Consultancy, Other: travel costs/ conference fee; Novartis: Consultancy, Other: travel costs/ conference fee. Schlenk: Boehringer Ingelheim: Research Funding; AstraZeneca: Research Funding; Roche: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria; Neovio Biotech: Honoraria; Hexal: Honoraria; Daiichi Sankyo: Honoraria, Research Funding; Celgene: Honoraria; Astellas: Honoraria, Research Funding, Speakers Bureau; Abbvie: Honoraria; Agios: Honoraria. Middeke: Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; Gilead: Consultancy; Abbvie: Consultancy, Honoraria; Jazz: Consultancy; Pfizer: Consultancy, Honoraria; Sanofi: Honoraria, Research Funding; Astellas: Consultancy, Honoraria; Novartis: Consultancy; Glycostem: Consultancy; UCB: Honoraria. Krause: Siemens: Research Funding; Takeda: Honoraria; Pfizer: Honoraria; art-tempi: Honoraria; Kosmas: Honoraria; Gilead: Other: travel support; Abbvie: Other: travel support. Schliemann: Philogen S.p.A.: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Other: travel grants; Astellas: Consultancy; AstraZeneca: Consultancy; Boehringer-Ingelheim: Research Funding; BMS: Consultancy, Other: travel grants; Jazz Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy; Roche: Consultancy; Pfizer: Consultancy. Haenel: GSK: Consultancy; Jazz: Consultancy, Honoraria; Bayer Vital: Honoraria; Takeda: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy; Celgene: Consultancy, Honoraria. Crysandt: Pfizer: Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria. Fransecky: Medac: Honoraria; Abbvie: Honoraria, Research Funding; Amgen: Honoraria; Takeda: Honoraria; Novartis: Honoraria. Einsele: Janssen, Celgene/BMS, Amgen, GSK, Sanofi: Consultancy, Honoraria, Research Funding. Seggewiss-Bernhardt: Astra-Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; ipsen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; EusaPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees. Platzbecker: AbbVie: Honoraria; Celgene/BMS: Honoraria; Janssen: Honoraria; Novartis: Honoraria; Geron: Honoraria; Takeda: Honoraria. Baldus: Amgen: Honoraria; Celgene/BMS: Honoraria; Jazz: Honoraria; Novartis: Honoraria. Dreger: Bluebird Bio: Consultancy; AstraZeneca: Consultancy, Speakers Bureau; BMS: Consultancy; AbbVie: Consultancy, Speakers Bureau; Janssen: Consultancy; Gilead Sciences: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Riemser: Consultancy, Research Funding, Speakers Bureau; Roche: Consultancy, Speakers Bureau. Müller-Tidow: Pfizer: Research Funding; Janssen: Consultancy, Research Funding; Bioline: Research Funding. Sauer: Takeda: Consultancy, Other: DSMB/SAB Member; Matterhorn Biosciences AG: Consultancy, Other: DSMB/SAB Member; Abbvie: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau. OffLabel Disclosure: off-label use of Venetoclax-based combination therapy in relapsed or refractory AML

Early results of the randomized placebo-controlled SORAML trial showed that, in patients with newly diagnosed acute myeloid leukaemia (AML), sorafenib led to a significant improvement in event-free (EFS) and relapse-free survival (RFS). In order to describe second-line treatments and their implications on overall survival (OS), we performed a study after a median follow-up time of 78 months. Newly diagnosed fit AML patients aged ≤60 years received sorafenib (n = 134) or placebo (n = 133) in addition to standard chemotherapy and as maintenance treatment. The 5-year EFS was 41 versus 27% (HR 0.68; p = 0.011) and 5-year RFS was 53 versus 36% (HR 0.64; p = 0.035). Allogeneic stem cell transplantation (allo SCT) was performed in 88% of the relapsed patients. Four years after salvage allo SCT, the cumulative incidence of relapse was 54 versus 35%, and OS was 32 versus 50%. The 5-year OS from randomization in all study patients was 61 versus 53% (HR 0.82; p = 0.282). In conclusion, the addition of sorafenib to chemotherapy led to a significant prolongation of EFS and RFS. Although the OS benefit did not reach statistical significance, these results confirm the antileukaemic activity of sorafenib.

Total metabolic tumor volume (TMTV) was measured in 510 patients with DLBCL participating in the PETAL trial. The present data provide information about the prognostic impact of total metabolic tumor volume using the fixed standardized uptake value (SUV4) instead of the relative SUV41max thresholding method. A Bland-Altman plot was created to compare both methods. For TMTV assessed by the SUV4 method a Cox regression was applied to determine its effect on time to progression, progression-free survival, and overall survival. Kaplan-Meier curves and corresponding hazard ratios were used to estimate the effect of TMTV alone or in combination with interim positron emission tomography response on patients’ survival. The data relate to the research article entitled “Dynamic risk assessment based on positron emission tomography scanning in diffuse large B-cell lymphoma: post-hoc analysis from the PETAL trial” [1].

Murine models of myeloid neoplasia show how leukemia infiltration alters the hematopoietic stem cell (HSC) niche to reinforce malignancy at the expense of healthy hematopoiesis. However, little is known about the bone marrow architecture in humans and its impact on clinical outcome. Here, we dissect the bone marrow niche in patients with acute myeloid leukemia (AML) at first diagnosis. We combined immunohistochemical stainings with global gene expression analyses from these AML patients and correlated them with clinical features. Mesenchymal stem and progenitor cells (MSPCs) lost quiescence and significantly expanded in the bone marrow of AML patients. Strikingly, their HSC- and niche-regulating capacities were impaired with significant inhibition of osteogenesis and bone formation in a cell contact–dependent manner through inhibition of cytoplasmic β-catenin. Assessment of bone metabolism by quantifying peripheral blood osteocalcin levels revealed 30% lower expression in AML patients at first diagnosis than in non-leukemic donors. Furthermore, patients with osteocalcin levels ≤11 ng/mL showed inferior overall survival with a 1-year survival rate of 38.7% whereas patients with higher osteocalcin levels reached a survival rate of 66.8%. These novel insights into the human AML bone marrow microenvironment help translate findings from preclinical models and detect new targets which might pave the way for niche-targeted therapies in AML patients.

Managing acute myeloid leukemia (AML) is often hampered by repeated failure to achieve complete remission as well as recurrent relapse that causes an emergent need for alternative salvage therapies. The efficacy of most salvage therapies is based on anthracycline combinations. In highly pretreated patients who are not eligible for anthracycline-based protocols therapeutic alternatives are limited. For this particular group we evaluated the efficacy and safety of fludarabine, cytarabine, granulocyte colony-stimulating factor (FLAG) in combination with etoposide (FLAG-Eto) in 36 patients. The complete remission rate (CR) was 25.7% with a median overall survival of 6 months (95% CI 4.5–7.7). The median disease-free survival for CR/CRi/MLFS (CR/CR with incomplete he­matological recovery/morphologic leukemia-free state) patients was 8 months (95% CI 0.6–15.5). The mortality rate on day 30 was 8% and increased on day 60 to 17%. Our results show meaningful anti-leukemic activity of the FLAG-Eto regimen with a moderate toxicity profile in heavily pretreated relapsed/refractory AML patients enabling consolidating allogeneic stem cell transplantation.

Background: Acute myeloid leukemia (AML) is characterized by a high relapse rate, indicating insufficient clearance of leukemia-initiating cells. Depending on genetic risk stratification, consolidating chemotherapy proves to significantly reduce the risk of relapse. In particular, in younger AML patients higher dosage of cytarabine appears to improve long-term outcome, while there is no apparent benefit of multiagent combination, compared to cytarabine monotherapy. However, to this end the optimal dosage of single agent cytarabine in consolidation therapy after 7+3 remission induction remains elusive. Methods: Here, we retrospectively assessed the impact of different dosages of cytarabine consolidation on outcome in a large real-world data set from the German Study Alliance Leukemia-Acute Myeloid Leukemia (SAL-AML) registry. Patients below 65 years of age, registered between April 2005 and September 2020 with non-acute promyelocytic leukemia, who attained complete remission after intensive induction and received at least one consolidation cycle with intermediate (IDAC) or high dose cytarabine (HiDAC) were selected. To account for differences in patient and disease characteristics between both groups, the average treatment effect was estimated by propensity score weighting. Results: 642 patients received HiDAC consolidation with a median dosage of 5794.88 (IQR, 4745.48-5971.56) mg/m 2/d with a median number of 3 cycles (IQR, 2-3), whereas 178 patients received IDAC consolidation with 1946.16 (IQR, 1869.51-2469.15) mg/m 2/d with a median of 2 cycles (IQR, 1-3). IDAC-treated patients showed in average a higher age (median (IQR) 58.5 (49-62) years vs. 50 (41-56) years) and more comorbidities with 43.8% having an HCT-CI score of 2-4, compared to 22.3% among HiDAC-treated patients. Alongside, significantly more secondary (5.1% vs. 3.1%) and therapy-related (12.4% vs. 4.1%) AML as well as more adverse (14.5% vs. 6.5%) and less favorable (40.6% vs. 56%) genetic risk features according to ELN 2017 risk classification were found among IDAC-treated patients. After propensity score weighting for differences in patient and disease characteristics, overall survival after 5 years was comparable between HiDAC-treated (71.1 %) and IDAC-treated (67.7%) patients. Moreover, no significant differences in relapse-free survival were observed after 5 years (47.4 vs. 45.2%). Notably, more patients treated with IDAC received allogeneic stem cell transplantation in first remission (37.6 vs. 19.8%) while significantly more HiDAC-treated patients underwent allogeneic stem cell transplantation in relapse (30.8 vs. 20.2%). Censoring for allogeneic stem cell transplantation in first remission revealed no significant survival difference with regard to cytarabine dosage. Considering only ELN favorable risk AML patients, there was no difference in 5-years overall (80.5% vs. 83.9%) nor relapse-free (57.7% vs. 56.8%) survival. Of note, significantly more patients treated with HiDAC suffered from ≥3 CTCAE infectious complications (56.7 vs. 44.1%), which was more striking in patients above 50 years of age. The rate of other ≥3 CTCAE non-hematological toxicities and secondary malignancies was comparable in both treatment groups. Conclusion: This retrospective analysis suggests no significant benefit of high dose cytarabine compared to intermediate dosages in consolidation for AML patients under 65 years of age, independent of ELN risk group. Disclosures Krause: Siemens: Research Funding; Takeda: Honoraria; Pfizer: Honoraria; art-tempi: Honoraria; Kosmas: Honoraria; Gilead: Other: travel support; Abbvie: Other: travel support. Schliemann: Philogen S.p.A.: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Other: travel grants; Astellas: Consultancy; AstraZeneca: Consultancy; Boehringer-Ingelheim: Research Funding; BMS: Consultancy, Other: travel grants; Jazz Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy; Roche: Consultancy; Pfizer: Consultancy. Haenel: Jazz: Consultancy, Honoraria; GSK: Consultancy; Bayer Vital: Honoraria; Takeda: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy; Celgene: Consultancy, Honoraria. Brummendorf: Takepart Media: Honoraria; Repeat Diagnostics: Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Patents & Royalties, Research Funding; Janssen: Honoraria; Bristol Myers: Research Funding. Fransecky: Abbvie: Honoraria, Research Funding; Medac: Honoraria; Novartis: Honoraria; Amgen: Honoraria; Takeda: Honoraria. Einsele: Janssen, Celgene/BMS, Amgen, GSK, Sanofi: Consultancy, Honoraria, Research Funding. Held: MSD: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Roche: Research Funding; Acortech Biopharma: Research Funding; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Platzbecker: Janssen: Honoraria; Celgene/BMS: Honoraria; AbbVie: Honoraria; Geron: Honoraria; Takeda: Honoraria; Novartis: Honoraria. Baldus: Amgen: Honoraria; Celgene/BMS: Honoraria; Novartis: Honoraria; Jazz: Honoraria. Mueller-Tidow: Janssen Cilag: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Bioline: Consultancy, Research Funding.

Achievement of complete remission (CR) signifies a crucial milestone in the therapy of acute myeloid leukemia (AML) while refractory disease is associated with dismal outcomes. Hence, accurately identifying patients at risk is essential to tailor treatment concepts individually to disease biology. Machine Learning (ML) is a branch of computer science that can process large data sets for a plethora of purposes. The underlying mechanism does not necessarily begin with a manually drafted hypothesis model. Rather the ML algorithms can detect patterns in pre-processed data and derive abstract information. We used ML to predict CR and 2-year overall survival (OS) in a large multi-center cohort of 1383 AML patients who received intensive induction therapy using clinical, laboratory, cytogenetic and molecular genetic data. To enable a customizable and reusable technological approach and achieve optimal results, we designed a data-driven platform with an embedded, automated ML pipeline integrating state-of-the-art software technology for data management and ML models. The platform consists of five scalable modules for data import and modelling, data transformation, model refinement, machine learning algorithms, feature support and performance feedback that are executed in an iterative manner to approach step-wisely the optimal configuration. To reduce dimensionality and the the risk of overfitting, dynamic feature selection was used, i.e. features were selected according to their support by feature selection algorithms. To be included in an ML model, a feature had to pass a pre-determined threshold of overall predictive power determined by summing the normalized scores of the feature selection algorithms. Features below the threshold were automatically excluded from the ML models for the respective iteration. In that way, features of high redundancy or low entropy were automatically filtered out. Our classification algorithms were completely agnostic of pre-existing risk classifications and autonomously selected predictive features both including established markers of favorable or adverse risk as well as identifying markers of so-far controversial relevance. De novo AML, extramedullary AML, double-mutated (dm) CEBPA, mutations of CEBPA-bZIP, NPM1, FLT3-ITD, ASXL1, RUNX1, SF3B1, IKZF1, TP53, U2AF1, t(8;21), inv(16)/t(16;16), del5/del5q, del17, normal or complex karyotypes, age and hemoglobin at initial diagnosis were statistically significant markers predictive of CR while t(8;21), del5/del5q, inv(16)/t(16;16), del17, dm CEBPA, CEBPA-bZIP, NPM1, FLT3-ITD , DNMT3A, SF3B1, U2AF1, TP53, age, white blood cell count, peripheral blast count, serum LDH and Hb at initial diagnosis as well as extramedullary manifestations were predictive for 2-year OS. For prediction of CR and 2-year OS, AUROCs ranged between 0.77 - 0.86 and 0.63 - 0.74, respectively. We provide a method to automatically select predictive features from different data types, cope with gaps and redundancies, apply and optimize different ML models, and evaluate optimal configurations in a scalable and reusable ML platform. In a proof-of-concept manner, our algorithms utilize both established markers of favorable or adverse risk and also provide further evidence for the roles of U2AF1, IKZF1, SF3B1, DNMT3A and bZIP mutations of CEBPA in AML risk prediction. Our study serves as a fundament for prospective validation and data-driven ML-guided risk assessment in AML at initial diagnosis for the individual patient. Image caption: Patient features were automatically selected by machine learning to predict complete remission (CR) and 2-year overall survival (OS) after intensive induction therapy. Based on a continuous feature support metric with a predefined cut-off of 0.5 (determined by optimal classification performance), 27 and 25 features were automatically selected for prediction of CR (A) and 2-year OS (C), respectively. For each of these features predicted by machine learning, odds ratios and 95% confidence intervals (CI) were calculated for CR (B) and 2 year OS (D). BMB: bone marrow blast count; FLT3h/low: FLT3-ITD ratio, h=high>0.5; Hb: hemoglobin; karyotype, c: complex aberrant karyotype (≥ 3 aberrations); karyotype, n: normal karyotype (no aberrations); LDH: lactate dehydrogenase; PBB: peripheral blood blast count; PLT: platelet count; WBC: white blood cell count. Figure 1 Figure 1. Disclosures Schetelig: Roche: Honoraria, Other: lecture fees; Novartis: Honoraria, Other: lecture fees; BMS: Honoraria, Other: lecture fees; Abbvie: Honoraria, Other: lecture fees; AstraZeneca: Honoraria, Other: lecture fees; Gilead: Honoraria, Other: lecture fees; Janssen: Honoraria, Other: lecture fees . Platzbecker: Janssen: Honoraria; Celgene/BMS: Honoraria; AbbVie: Honoraria; Novartis: Honoraria; Takeda: Honoraria; Geron: Honoraria. Müller-Tidow: Pfizer: Research Funding; Janssen: Consultancy, Research Funding; Bioline: Research Funding. Baldus: Celgene/BMS: Honoraria; Amgen: Honoraria; Novartis: Honoraria; Jazz: Honoraria. Krause: Siemens: Research Funding; Takeda: Honoraria; Pfizer: Honoraria; art-tempi: Honoraria; Kosmas: Honoraria; Gilead: Other: travel support; Abbvie: Other: travel support. Haenel: Bayer Vital: Honoraria; Jazz: Consultancy, Honoraria; GSK: Consultancy; Takeda: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Amgen: Consultancy; Celgene: Consultancy, Honoraria. Schliemann: Philogen S.p.A.: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Other: travel grants; Astellas: Consultancy; AstraZeneca: Consultancy; Boehringer-Ingelheim: Research Funding; BMS: Consultancy, Other: travel grants; Jazz Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy; Roche: Consultancy; Pfizer: Consultancy. Middeke: Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Jazz: Consultancy; Astellas: Consultancy, Honoraria; Sanofi: Honoraria, Research Funding; Novartis: Consultancy; Gilead: Consultancy; Glycostem: Consultancy; UCB: Honoraria.

Background In newly diagnosed acute myeloid leukemia (AML) with FLT3 mutations (FLT3-mut), the tyrosine kinase inhibitor midostaurin (MIDO) in combination with intensive chemotherapy (IC) is considered standard of care (SoC). Subgroup analyses from the ALFA 0701 trial indicate that the addition of the conjugated CD33 antibody gemtuzumab ozogamicin (GO) to IC increases efficacy in the FLT3-ITD subgroup of patients (pts), providing a rationale for the combined use of MIDO plus GO with IC in newly diagnosed FLT3-mut AML. On the other hand, there is evidence that the subgroup of core-binding factor (CBF) AML benefits from the inhibition of the tyrosine kinase KIT with respect to survival end points. In this respect, MIDO is a more powerful KIT inhibitor as compared to dasatinib which has been applied in previous studies. While the combination of IC plus GO in induction treatment is considered SoC in patients with CBF AML the addition of MIDO to SoC seems promising to further improve treatment outcomes in the CBF subgroup. We therefore set up the clinical trial MOSAIC composed of a phase-I part to prospectively assess the feasibility of combining MIDO plus GO with IC (MODULE), followed by a randomized phase-II part evaluating the benefit of adding GO to SoC in FLT3-mut AML (MAGMA) and of adding MIDO to SoC in CBF AML (MAGNOLIA). Here, we report the results of the phase-I part (MODULE). Methods MODULE is a dose escalation phase-I trial following a 3+3 design. Eligibility criteria include newly diagnosed AML harboring either FLT3 or CBF mutations, and fitness for IC. Standard 7+3 IC using cytarabine 200 mg/m 2 continuous infusion over 7 days plus daunorubicin 60 mg/m 2 on 3 days was combined with increasing doses of MIDO and GO in three dose levels: 1 st dose level (GO 3 mg/m 2 i.v. QD on day 1+4 plus 25 mg MIDO p.o. BID days 8-21); 2 nd dose level (GO 3 mg/m 2 i.v. QD on day 1+4 plus 50 mg MIDO p.o. BID days 8-21); 3 rd dose level (GO 3 mg/m 2 i.v. QD on day 1+4+7 plus 50 mg MIDO p.o. BID days 8-21). Based on the 3+3 design, each dose cohort consisted of three but maximal six pts. The protocol predefined the maximal tolerable dose (MTD) as reached if ≤2 dose-limiting toxicity events (DLTs) would occur in maximum six evaluable pts who received ≥80% of the planned study therapy. Results From September 2020 to July 2021, 11 pts were enrolled. In the 1 st dose level, three pts completed the regular study period without DLT, whereas treatment had to be discontinued in one patient on day 6 before commencement of MIDO due to infusion related reaction CTC grade 4. This patient was subsequently replaced. In the 2 nd dose level, one of three enrolled pts experienced neutropenic colitis CTC grade 3 on day 14 of treatment, which was classified as DLT. The colitis fully recovered by day 27 after commencement of treatment. As a result of the DLT, the dose cohort was subsequently extended by three additional pts. Of those, one patient developed signs of sinusoidal obstruction syndrome (SOS) CTC grade 3 starting on day 13 of treatment. SOS was classified as DLT. The patient was treated with defibrotide and supportive care until recovery on day 28. Another patient had to discontinue treatment on day 14 due to inability of swallowing MIDO. This patient was replaced as the target dose of MIDO was not reached. As predefined in the study protocol, the occurrence of 2 DLTs in six evaluable pts precluded further dose escalation to the 3 rd dose level and defined the 2 nd dose level as safe and feasible. A total number of 5 serious adverse events (SAEs) were observed among all 11 pts who completed the DLT evaluation period: infusion related reaction, colitis, parvo-B19 infection, prolonged neutropenia CTC grade 4, and SOS. An unexpected increase in frequency of common AML adverse events was not observed. The 30-day mortality among all enrolled pts was 0%. After blood count recovery, remission assessment showed complete remission (CR) in 7 pts, CR with incomplete hematologic/platelet recovery (CRi/CRp) in 3 pts and primary refractory disease in one patient. Conclusion GO standard dose on days 1 + 4 and MIDO standard dose on days 8-21 of induction treatment is defined as MTD which can be safely combined with standard IC in newly diagnosed AML. In the phase-I cohort of the MOSAIC trial, CR/CRi/CRp rates of 91% were reached. Based on the results of this dose finding trial the MTD of combined MIDO and GO will be defined as phase-II dose for the randomized phase-II studies in CBF and FLT-mut AML. Figure 1 Figure 1. Disclosures Röllig: Jazz: Honoraria; Amgen: Honoraria; Bristol-Meyer-Squibb: Honoraria, Research Funding; Janssen: Honoraria; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Roche: Honoraria, Research Funding. Schliemann: Philogen S.p.A.: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Other: travel grants; Astellas: Consultancy; AstraZeneca: Consultancy; Boehringer-Ingelheim: Research Funding; BMS: Consultancy, Other: travel grants; Jazz Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy; Roche: Consultancy; Pfizer: Consultancy. Fransecky: Novartis: Honoraria; Abbvie: Honoraria, Research Funding; Amgen: Honoraria; Takeda: Honoraria; Medac: Honoraria. Baldus: Novartis: Honoraria; Amgen: Honoraria; Celgene/BMS: Honoraria; Jazz: Honoraria. Wermke: Novartis, Roche, Pfizer, BMS: Consultancy, Honoraria, Research Funding.

Acute myeloid leukemia (AML) is a hematologic malignancy that is treated in medically fit patients with intensive induction chemotherapy (IT) and postremission therapy to achieve a complete and long-term remission. The incidence of obesity in the general population is steadily increasing and has been identified as a major risk factor for all-cause mortality. Despite previous studies assessing the role of obesity in AML patients undergoing IT, there is an ongoing debate on the impact of obesity on patient outcome as well as the optimal dosing strategy in obese AML patients. We conducted a retrospective registry study assessing 1677 AML patients who were treated with IT for newly diagnosed AML. The primary endpoint was overall survival (OS) while event-free survival (EFS), the rate of first complete remission (CR1), relapse/refractory disease and non-relapse/refractory-related mortality (NRRrM), treatment-related toxicities, patient comorbidities and chemotherapy dosing strategies were analyzed as secondary endpoints. Obese patients (body mass index, BMI ≥ 30) displayed a significant inferior median OS (29.44 vs. 47.94 months, p = 0.015) without a significant difference in median EFS (7.8 vs. 9.89 months, p = 0.3) compared to non-obese patients (BMI < 30). The cumulative incidence (CI) of NRRrM was significantly increased in obese patients compared to non-obese patients while no differences could be observed regarding the CI of relapsed or refractory disease. Obesity was identified as an independent risk factor for death (HR 1.27, [95% CI 1.07-1.51], p = 0.005) in a multivariable Cox regression analysis. When the cohort was stratified by age (≥/< 60 years), the difference in OS as well as the significantly increased CI of NRRrM was only observed in patients ≥ 60 years. Notably, obese patients demonstrated higher rates of cardiovascular and metabolic comorbidities regardless of their age. No disparities for OS, EFS, CR1 rate or treatment-related toxicities were observed when the entire study population was stratified for the used dosing strategy (dose calculation using total body weight, idealized body weight, adjusted idealized body weight or capped at body surface area of 2 m 2). In conclusion, the present study identifies obesity as a major independent risk factor for worse overall survival and increased CI of non-relapse/refractory-related mortality in older (≥60 years) AML patients undergoing curative IT. These findings may be most likely attributed to obesity related comorbidities and not to dose adaption of chemotherapy in obese AML patients. Disclosures Schliemann: Boehringer-Ingelheim: Research Funding; Abbvie: Consultancy, Other: travel grants; Philogen S.p.A.: Consultancy, Honoraria, Research Funding; Astellas: Consultancy; AstraZeneca: Consultancy; BMS: Consultancy, Other: travel grants; Jazz Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy; Roche: Consultancy; Pfizer: Consultancy. Krause: Siemens: Research Funding; Takeda: Honoraria; Pfizer: Honoraria; art-tempi: Honoraria; Kosmas: Honoraria; Gilead: Other: travel support; Abbvie: Other: travel support. Haenel: Jazz: Consultancy, Honoraria; GSK: Consultancy; Bayer Vital: Honoraria; Takeda: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy; Celgene: Consultancy, Honoraria. Fransecky: Amgen: Honoraria; Abbvie: Honoraria, Research Funding; Novartis: Honoraria; Medac: Honoraria; Takeda: Honoraria. Burchert: Novartis: Honoraria, Research Funding; AOP Orphan: Honoraria, Research Funding; Pfizer: Honoraria; Incyte: Honoraria; Gilead: Honoraria; BMS: Honoraria. Crysandt: Incyte: Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees. Müller-Tidow: Janssen: Consultancy, Research Funding; Bioline: Research Funding; Pfizer: Research Funding. Platzbecker: Celgene/BMS: Honoraria; AbbVie: Honoraria; Janssen: Honoraria; Novartis: Honoraria; Takeda: Honoraria; Geron: Honoraria. Baldus: Jazz: Honoraria; Novartis: Honoraria; Amgen: Honoraria; Celgene/BMS: Honoraria.

In the past decade outcome of adult ALL was improved significantly using pediatric-based chemotherapy in combination with risk-adapted stem cell transplantation (SCT) and targeted therapies. The GMALL Trial 08/2013 (NCT02881086) for patients (pts) aged 18-55 years (yrs) with newly diagnosed ALL/LBL has a BFM-based 2-phase induction, up to 8 cycles of PEG-asparaginase (ASP) with up to 7 cycles of HDMTX, HDAC, a reinduction phase and conventional maintenance up to 2.5 yrs. Two cycles Nelarabine are implemented for standard risk (SR) T-ALL. Pts with B-precursor-ALL (B-ALL) receive Rituximab independent of CD20 expression (Ph+ only if CD20+). Ph+ ALL pts receive Imatinib and a dose reduced induction (Vincristine, Dexamethasone, ASP). ASP is scheduled in induction 1 (IP1) (d 20) and 2 (d 34 for Ph+ and d 44 for Ph-) and dose is adapted to risk factors for hepatotoxicity. Pts with BMI>30 and/or liver steatosis receive 500 U/m 2, whereas 2000 U/m 2 is the standard dose. It is recommended to withhold the 2 nd dose of ASP in case of clinically relevant ASP-associated toxicities. Pts with high-risk (HR) features (WBC > 30,000/µl in B-ALL, pro B-ALL-, KMT2A rearrangement, early/mature T-ALL) or Ph+ ALL are considered for SCT in CR1 after 1 st consolidation (C1). Pts with MolFail (table 1) after C1 are candidates for targeted therapy (Blinatumomab, Nelarabin) followed by SCT. Randomization (R) I evaluates CNS irradiation versus i.th. prophylaxis in B- ALL/LBL. R II compares SCT versus SR therapy in HR pts with MolCR after induction. Both randomizations are blinded and not available for analysis. The trial is ongoing and scheduled to recruit 950 pts. Between 8/2017-4/2021 770 pts from 78 centers were included and 705 were evaluable. The median age was 35 (18-55) yrs, 638 had ALL (B,Ph-: 55%, Ph+: 20%, T: 25%,) and 67 pts LBL (B:12%; T:88%). For ALL the hematologic (Hem) CR rate after C1 was 93% and the MolCR Rate 61% (75% mol. response) (table 1). HemCR rate was 72% in LBL with 21% PR. PET CT was negative in half of the LBL PR cases. The lowest HemCR rate was observed in early T-ALL (83%) together with a MolCR rate of 45% (71% mol. response). In Ph- pts 2000 U/m 2 as first dose ASP was administered in 66%, 500 U/m 2 in 24%, no ASP in 1% and other doses in 9%. In pts with Ph+ ALL the respective numbers were 61%, 21%, 6% and 13%. For the 2nd dose the numbers were 43%, 21%,13% and 22% for Ph- and 41%, 24%, 13% and 22% for Ph+ pts. Bilirubine increases grade III/IV were observed in Ph- ALL in 18% of the cases treated with 500 U/m 2 vs 24% for 2000 U/m 2. In Ph+ ALL the respective numbers were 5% vs 3%. GOT/GPT grade III/IV increases were observed 29% of Ph- ALL pts treated with 500 U/m 2 vs 25% of those with 2000 U/m 2. The respective numbers for Ph+ ALL were 24% and 40%. At a median follow-up of 23 mo, the overall survival (OS) for all pts (N=705) was 88% and 76% at 1 and 3 yrs resp (subgroups see table 1). OS was correlated to age, 87%, 74%, 69% and 73% at 3 yrs for pts aged 18-25, 26-35, 36-45 and 46-55 yrs resp. SR T-ALL reached an OS of 86% at 3 yrs with a conventional and nelarabine based consolidation. 79% of pts with an indication for SCT were transplanted (64 sibling, 174 MUD). The OS of SCT pts after SCT was 75% at 3 yrs. 63 pts with MolFail became candidates for a targeted therapy, which was realized in 89% of the cases. The molecular response was evaluable in 51 pts and reached 55% (N=40) and 18% (N=11) after one cycle of Blinatumomab or Nelarabin resp. Pts with MolFail (N=63) achieved an OS of 84% at 1y and 72% at 3 years resp (71% for Ph- and 76% for Ph+). This large, ongoing prospective multicenter trial provides promising preliminary results. This applies also to those aged 45-55 yrs underlining that adult pts beyond the variable AYA definitions can benefit from pediatric-based therapy. Intensive and individualized ASP therapy was feasible. Whereas high HemCR rates were observed in nearly all subgroups, MolCR rates ranged from 41-74% and a relevant proportion remained MRD low positive underlining the need for detailed MRD classification. MRD-based targeted treatment was realized in a high proportion of pts. Responses to Blinatumomab in MolFail were lower compared to previous trials. Responses to Nelarabine in MolFail T-ALL pts were only 18%. OS of MolFail pts however was promising with the combination of targeted therapy and SCT. Thus, SCT is still a key component, contributing to improved outcomes although the overall proportion of SCT was lower than in previous GMALL trials. Funded by Deutsche Krebshilfe Figure 1 Figure 1. Disclosures Goekbuget: Servier: Consultancy, Other; Morphosys: Consultancy; Astra Zeneca: Other: Invited talk for company sponsored symposia (with honor); Amgen: Consultancy, Other: Invited talks for company sponsored symposia (with honoraria); Research funding for institution; Novartis: Consultancy, Other: Research funding for Institution; Pfizer: Consultancy, Other: Research funding for institution; Jazz Pharmaceuticals: Other: Research funding for institution; Incyte: Other: Research funding for Institution; Cellestia: Consultancy; Erytech: Consultancy; Abbvie: Other; Gilead/Kite: Consultancy. Stelljes: Pfizer: Consultancy, Research Funding, Speakers Bureau; Medac: Speakers Bureau; Amgen: Consultancy, Speakers Bureau; MSD: Consultancy, Speakers Bureau; Celgene/BMS: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Kite/Gilead: Consultancy, Speakers Bureau. Viardot: Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; University Hospital of Ulm: Current Employment; F. Hoffmann-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kite/Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Nachtkamp: Jazz: Honoraria; Bsh medical: Honoraria; Celgene: Other: Travel Support. Topp: Novartis: Consultancy; Roche: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Janssen: Consultancy; Amgen: Consultancy, Research Funding; Macrogeniecs: Research Funding; Regeneron: Consultancy, Research Funding; Gilead: Research Funding; Universitatklinikum Wurzburg: Current Employment. Wäsch: Sanofi: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Pfizer: Consultancy; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Novartis: Consultancy; BMS/Celgene: Consultancy; Gilead: Consultancy. Vucinic: Abbvie: Honoraria, Other: Travel Sponsoring; MSD: Honoraria; Janssen: Honoraria, Other: Travel Sponsoring; Gilead: Honoraria, Other: Travel Sponsoring; Novartis: Honoraria. Baldus: Novartis: Honoraria; Amgen: Honoraria; Celgene/BMS: Honoraria; Jazz: Honoraria. Brüggemann: Amgen: Other: Advisory Board, Travel support, Research Funding, Speakers Bureau; Incyte: Other: Advisory Board; Janssen: Speakers Bureau. Pfeifer: Incyte: Honoraria, Research Funding. Schwartz: Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Travel grants, Speakers Bureau; Novartis: Speakers Bureau; Jazz Pharmaceuticals: Other: Travel grants, Speakers Bureau; BTG International Inc: Membership on an entity's Board of Directors or advisory committees; MSD Sharp & Dohme: Membership on an entity's Board of Directors or advisory committees; Basilea: Other: Travel grants; Gilead: Other: Travel grants, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Morphosys: Research Funding. Fiedler: Abbvie: Consultancy, Honoraria, Other: Meeting attendance, Preparation of information material; Amgen: Consultancy, Honoraria, Other: Meeting attendance, Preparation of information material, Patents & Royalties, Research Funding; Ariad/Incyte: Honoraria; Celgene: Consultancy, Honoraria; Jazz: Consultancy, Honoraria, Other: Meeting attendance, Preparation of information material; MorphoSys: Consultancy, Honoraria; Novartis: Honoraria; Pfizer: Consultancy, Honoraria, Research Funding; Daiichi Sanyko: Consultancy, Other: Meeting attendance, Preparation of information material; Stemline: Consultancy; Servier: Consultancy, Other: Meeting attendance, Preparation of information material. OffLabel Disclosure: Nelarabine in newly diagnosed T-ALL

Introduction: Acute lymphoblastic leukemia (ALL) represents approx. 5% of all newly diagnosed leukemias in patients between 55 and 70 years of age. Despite recent advances especially in younger patients, the prognosis of elderly patients with ALL remains dismal, even after moderately intensive chemotherapy. Incorporation of antibody-based therapies in the first line induction therapy bears the potential of a significant increased response rate and survival with the reduction of treatment toxicity. Methods: This open label phase II study of the German Multicenter Study Group on Adult Acute Lymphoblastic Leukemia was conducted at 13 centers. Patients aged >55 years with newly diagnosed Ph/BCR-ABL negative acute B-precursor ALL were eligible. Leukemic blasts had CD22 surface expression of at least 20%. The 1st induction cycle consisted of InO 0.8mg/m2 on day1 and 0.5mg/m2 on d8 and d15 together with dexamethasone 10 mg/m2 (day7-8, day14-17) and one intrathecal injection (i.th.) of methotrexate (MTX), cytarabine (AraC) and dexamethasone (Dex). The 2nd and 3rd induction cycle consisted of InO 0.5mg/m2 on day 1, 8 and 15 plus i.th. MTX/AraC/Dex. Patients achieving a complete remission (CR) were offered to receive 5 conventional consolidation therapies (3 x ID-MTX/asparaginase; 2 x ID-AraC) and one reinduction therapy (idarubicine/ AraC/ cyclophosphamide / Dex.) in combination with rituximab (for CD20+ ALL), followed by a maintenance therapy with 6-MP/MTX. The primary endpoint was event free survival (EFS) at 12-months follow-up. An event was defined as any of the following: persisting bone marrow blasts after 2 cycles of InO, relapse or death. An event rate of ≤40% at 12 months follow-up was considered to qualify the experimental treatment as very promising for additional testing. Under the assumption of one-sided type I error of 5% and 80% power, 42 evaluable patients were needed for primary endpoint analysis (registered with ClinicalTrials.gov, identifier: NCT03460522). Results: As of July 2021, 45 patients were included, with induction results available for 43 patients. Two patients were excluded per protocol from further analysis, as they received only one induction: 1 prolonged toxicity (CR after induction), 1 withdrawn consent. Median age at initial diagnosis was 64 years (range 56-80 years). 38 patients were diagnosed with a common- and 5 with a pro-B ALL. Median CD22 expression on leukemic blasts was 69% (range 21-99%). Due to suspected therapy related liver toxicities, a single patient received only 2 induction cycles (complete remission after 1st induction). All other patients completed 3 cycles of induction therapy and achieved complete remission (CR/CRi), mainly after the 1st induction. Results of minimal residual disease (MRD), measured by real-time quantitative PCR, are available for all 43 patients, with 23/43 (53%) and 31/42 (74%) patients being MRD negative after 2nd and 3rd induction therapy, respectively. Four patients with MRD failure (≥10 -4) after the 3rd induction therapy are still in CR (2 were treated with conventional chemotherapy per this protocol, one proceeded to allogeneic stem cell transplantation (aSCT), one received blinatumomab). MRD below the threshold of 10 -4 was detected in 15 patients after the 2nd induction (no relapse occurred so far). 8 of these 15 patients were MRD negative after the 3rd induction. So far, 7 events have been reported (during year 1: 3 deaths in CR and 1 relapsed ALL; during year 2: 1 death in CR and 2 patients with relapse). With a median follow-up of 422 days, the probability of OS at 1 and 2 years is 91% (95% C.I. 80-100%) and 77% (95% C.I. 57-96%), respectively. 4 patients received an aSCT in 1st CR, 1 patient in 2nd CR. Regarding adverse events (AEs) during induction cycles 1, 2 and 3, most common AEs ≥CTC grade 3 reported were leukocytopenia (in 60%, 12% and 3% of all cases, respectively), anemia (28%, 2%, 0%), thrombocytopenia (35%, 7%, 3%) and elevation of liver enzymes (14%, 5%, 0%). So far, one patient has been reported with suspected veno occlusive disease (after 2nd induction therapy). Conclusion: Three cycles of InO as induction therapy for the treatment of elderly patients with acute B-cell ALL results in very high remission rates with MRD-response in up to 90% (MRD negativity or MRD-levels Figure 1 Figure 1. Disclosures Stelljes: Pfizer: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Medac: Speakers Bureau; MSD: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Celgene/BMS: Consultancy, Speakers Bureau; Kite/Gilead: Consultancy, Speakers Bureau. Wäsch: Sanofi: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Pfizer: Consultancy; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Novartis: Consultancy; BMS/Celgene: Consultancy; Gilead: Consultancy. Nachtkamp: Jazz: Honoraria; Bsh medical: Honoraria; Celgene: Other: Travel Support. Haenel: Jazz: Consultancy, Honoraria; GSK: Consultancy; Bayer Vital: Honoraria; Takeda: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy; Celgene: Consultancy, Honoraria. Berdel: Philogen S.p.A.: Consultancy, Current equity holder in publicly-traded company, Honoraria, Membership on an entity's Board of Directors or advisory committees. Goekbuget: Amgen: Consultancy, Other: Invited talks for company sponsored symposia (with honoraria); Research funding for institution; Astra Zeneca: Other: Invited talk for company sponsored symposia (with honor); Erytech: Consultancy; Cellestia: Consultancy; Incyte: Other: Research funding for Institution; Jazz Pharmaceuticals: Other: Research funding for institution; Novartis: Consultancy, Other: Research funding for Institution; Gilead/Kite: Consultancy; Morphosys: Consultancy; Pfizer: Consultancy, Other: Research funding for institution; Servier: Consultancy, Other; Abbvie: Other. OffLabel Disclosure: Inotuzumab Ozogamicin

Background In a recent phase-III trial CPX-351 (Jazz Pharmaceuticals, Palo Alto, CA), a liposomal encapsulation of cytarabine and daunorubicin, has shown higher remission rates and longer overall survival (OS) in patients aged 60 to 75 years with AML with myelodysplasia-related changes (AML-MRC) or therapy-related AML (t-AML) in comparison to conventional 7+3 regimen. Based on this CPX-351 has been approved in the USA 2017 and in Europe 2018 for adult patients with newly-diagnosed AML-MRC or t-AML. Still, several issues such as age ( Design/Methods: For this retrospective analysis, we collected data on baseline characteristics, treatment details including allo-HCT and outcome from patients with newly-diagnosed AML-MRC or t-AML, who were treated with CPX-351 according to the EMA label between 2018 and 2020 in 25 German centers participating in the Study Alliance Leukemia (SAL), German Cooperative Transplant Study Group and the AML Study Group (AMLSG). Results: A total of 188 patients (median age 65 years, range 26 to 80) with t-AML (29%) or AML-MRC (70%) including 46 patients (24%) Conclusion: The results from this real-world analysis confirm CPX-351 as an efficient treatment for these high-risk AML patients bridging to facilitating allo-HCT in many patients with encouraging outcome after transplantation. Disclosures Röllig: AbbVie: Honoraria, Research Funding; Amgen: Honoraria; Bristol-Meyer-Squibb: Honoraria, Research Funding; Janssen: Honoraria; Jazz: Honoraria; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Roche: Honoraria, Research Funding. Stelljes: Pfizer: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Medac: Speakers Bureau; Celgene/BMS: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; MSD: Consultancy, Speakers Bureau; Kite/Gilead: Consultancy, Speakers Bureau. Gaidzik: Janssen: Speakers Bureau; Pfizer: Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Unglaub: Novartis: Consultancy, Other: travel costs/ conference fee; JazzPharma: Consultancy, Other: travel costs/ conference fee. Thol: Abbvie: Honoraria; Astellas: Honoraria; BMS/Celgene: Honoraria, Research Funding; Jazz: Honoraria; Novartis: Honoraria; Pfizer: Honoraria. Krause: Siemens: Research Funding; Takeda: Honoraria; Pfizer: Honoraria; art-tempi: Honoraria; Kosmas: Honoraria; Gilead: Other: travel support; Abbvie: Other: travel support. Haenel: Celgene: Consultancy, Honoraria; Amgen: Consultancy; Novartis: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Bayer Vital: Honoraria; Jazz: Consultancy, Honoraria; GSK: Consultancy. Vucinic: Novartis: Honoraria; Janssen: Honoraria, Other: Travel Sponsoring; Abbvie: Honoraria, Other: Travel Sponsoring; Gilead: Honoraria, Other: Travel Sponsoring; MSD: Honoraria. Fransecky: Novartis: Honoraria; Medac: Honoraria; Abbvie: Honoraria, Research Funding; Amgen: Honoraria; Takeda: Honoraria. Holtick: Celgene: Honoraria; Sanofi: Honoraria. Kobbe: Celgene: Research Funding. Holderried: Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Speakers Bureau; Gilead Sciences: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; MSD: Speakers Bureau; Daiichi Sankyo: Other: travel support; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Therakos: Other: Travel support; Janssen: Other: Travel support; Abbvie: Other: Travel support; Eurocept Pharmaceuticals: Other: Travel support; Medac: Other: Travel support. Heuser: Astellas: Research Funding; Bayer AG: Honoraria, Research Funding; BMS/Celgene: Research Funding; Jazz Pharmaceuticals: Honoraria, Research Funding; BergenBio: Research Funding; Daichi Sankyo: Honoraria, Research Funding; Karyopharm: Research Funding; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Roche: Research Funding; Tolremo: Honoraria; AbbVie: Honoraria; Janssen: Honoraria. Sauer: Pfizer: Consultancy, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Matterhorn Biosciences AG: Consultancy, Other: DSMB/SAB Member; Takeda: Consultancy, Other: DSMB/SAB Member. Goetze: Abbvie: Other: Advisory Board; BMS/Celgene: Other: Advisory Board, Research Funding. Döhner: Jazz Roche: Consultancy, Honoraria; Agios and Astex: Research Funding; Astellas: Research Funding; Abbvie: Consultancy, Honoraria; Janssen: Honoraria, Other: Advisory Board; Daiichi Sankyo: Honoraria, Other: Advisory Board; Novartis: Consultancy, Honoraria, Research Funding; Celgene/BMS: Consultancy, Honoraria, Research Funding. Döhner: Jazz Pharmaceuticals: Honoraria, Research Funding; Agios: Honoraria, Research Funding; Pfizer: Research Funding; Bristol Myers Squibb: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Gilead: Honoraria; Janssen: Honoraria; Helsinn: Honoraria; GEMoaB: Honoraria; Amgen: Honoraria, Research Funding; Astellas: Honoraria, Research Funding; Astex Pharmaceuticals: Honoraria; AstraZeneca: Honoraria; Berlin-Chemie: Honoraria; Oxford Biomedica: Honoraria; Roche: Honoraria. Schliemann: Philogen S.p.A.: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Other: travel grants; Astellas: Consultancy; AstraZeneca: Consultancy; Boehringer-Ingelheim: Research Funding; BMS: Consultancy, Other: travel grants; Jazz Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy; Roche: Consultancy; Pfizer: Consultancy. Schetelig: Roche: Honoraria, Other: lecture fees; Novartis: Honoraria, Other: lecture fees; BMS: Honoraria, Other: lecture fees; Abbvie: Honoraria, Other: lecture fees; AstraZeneca: Honoraria, Other: lecture fees; Gilead: Honoraria, Other: lecture fees; Janssen: Honoraria, Other: lecture fees . Germing: Novartis: Honoraria, Research Funding; Janssen: Honoraria; Bristol-Myers Squibb: Honoraria, Other: advisory activity, Research Funding; Celgene: Honoraria; Jazz Pharmaceuticals: Honoraria. Schroeder: JAZZ: Honoraria, Research Funding.

Clinical symptoms of hemophagocytic lymphohistiocytosis (HLH) are based on an excessive inflammatory response. Not only the diversity of the putative underlying etiologies of this rare syndrome but also the subsequent large variety of symptoms complicate the diagnosis of HLH in adult patients. However, early diagnosis and immediate treatment initiation are imperative for clinical outcome. In this article, we will review the diagnostic criteria of HLH and, in this context, discuss 6 cases, each of whom presented with a different clinical appearance causally associated with distinct malignant and nonmalignant diseases, exemplifying the spectrum of associations and manifestations of HLH.

The authors regret that they confused the colours of the time-to-progression curves in Figure 4C and Figure 4D. The correct Figure 4 appears below. [Figure presented] The authors would like to apologise for any inconvenience caused.

In the prostate, stem and progenitor cell regenerative capacities have been ascribed to both basal and luminal epithelial cells. Here, we show that a rare subset of mesenchymal cells in the prostate are epithelial-primed Nestin-expressing cells (EPNECs) that can generate self-renewing prostate organoids with bipotential capacity. Upon transplantation, these EPNECs can form prostate gland tissue grafts at the clonal level. Lineage-tracing analyses show that cells marked by Nestin or NG2 transgenic mice contribute to prostate epithelium during organogenesis. In the adult, modest contributions in repeated rounds of regression and regeneration are observed, whereas prostate epithelial cells derived from Nestin/NG2-marked cells are dramatically increased after severe irradiation-induced organ damage. These results indicate that Nestin/NG2 expression marks a novel radioresistant prostate stem cell that is active during development and displays reserve stem cell activity for tissue maintenance.

Transplantation of hematopoietic cells from a healthy individual (allogeneic hematopoietic cell transplantation (allo-HCT)) demonstrates that adoptive immunotherapy can cure blood cancers: still, post-transplantation relapses remain frequent. To explain their drivers, we analyzed the genomic and gene expression profiles of acute myeloid leukemia (AML) blasts purified from patients at serial time-points during their disease history. We identified a transcriptional signature specific for post-transplantation relapses and highly enriched in immune-related processes, including T cell costimulation and antigen presentation. In two independent patient cohorts we confirmed the deregulation of multiple costimulatory ligands on AML blasts at post-transplantation relapse (PD-L1, B7-H3, CD80, PVRL2), mirrored by concomitant changes in circulating donor T cells. Likewise, we documented the frequent loss of surface expression of HLA-DR, -DQ and -DP on leukemia cells, due to downregulation of the HLA class II regulator CIITA. We show that loss of HLA class II expression and upregulation of inhibitory checkpoint molecules represent alternative modalities to abolish AML recognition from donor-derived T cells, and can be counteracted by interferon-gamma or checkpoint blockade, respectively. Our results demonstrate that the deregulation of pathways involved in T cell-mediated allorecognition is a distinctive feature and driver of AML relapses after allo-HCT, which can be rapidly translated into personalized therapies.

Acute myeloid leukemia (AML) is characterized by a high failure rate to achieve complete remission as well as high relapse rates that cause an emergent need for efficient and tolerable salvage therapies. The combination of FLAG with idarubicin (FLAG-Ida) is a widely used protocol. However, its efficacy has been analyzed in only a limited number of studies with majorly small patient cohorts. Here, we analyzed 132 patients with largely primary refractory or first-time relapsed AML treated according to the FLAG-Ida protocol. The overall complete remission rate (CR + CRi) was 56% with a median overall survival of 15 months (95% CI, 5.7-25.1). The median disease-free survival for CR/CRi-patients was not reached. The mortality rate on day 30 was 9% and increased on day 60 to 16%. Our results show in relapsed/refractory AML patients a high efficacy and compatibility for the FLAG-Ida regimen.

Acute myeloid leukemia (AML) is characterized by an early failure of healthy hematopoiesis and a high relapse rate, caused by persistent leukemia initiating cells in the bone marrow niche. The hematopoietic stem cell niche in myeloid malignancies shows severe structural and functional alterations with an inflammatory response upon leukemia infiltration and impaired immunosurveillance. CD38 is a glycoprotein that is expressed on various immunoregulatory cells and commonly on AML blasts. Targeting CD38 by using the monoclonal antibody daratumumab showed high efficacy in multiple myeloma which is mediated by both cell-autonomous as well as immunomodulatory mechanisms. In this study we have investigated the anti-leukemic efficacy of daratumumab as well as its underlying mechanisms in AML. Using an in vitro co-culture model with different human AML cell lines together with a fibroblast cell line (MS-5) or human umbilical vein endothelial cells (HUVEC) revealed a significant reduction in AML cell growth upon daratumumab treatment in 5 of 8 AML cell lines. Interestingly, anti-leukemic activity of daratumumab was more pronounced when co-cultured with MS-5 stroma cells and to lower extent with HUVECs as compared to mono-cultured AML cells (mean cell reduction in MS-5 co-culture, range from 12.9 to 31%; in HUVEC co-culture, range from 1.9 to 24.1% and in mono-culture, range from 9.9 to 18%). To validate the anti-leukemic activity of daratumumab in human AML and to elaborate the microenvironment-mediated effects we created a 3D invitro model with HUVECs and human mesenchymal spheres cultured with primary AML or normal donor cells. We could demonstrate that this triple-culture model led to an increased growth support for both AML as well as normal donor samples as compared to mono-cultured cells. Adding daratumumab to mono-cultured AML cells reduced cell growth by only 7.2% (p To prove the anti-leukemic activity of daratumumab in AML in vivo we intravenously transplanted primary human AML cells into immunodeficient NOD scid gamma (NSG) mice. Leukemic mice were treated with ATRA over 4 weeks and once weekly with either daratumumab or IgG1 control. Preliminary results show a reduction in circulating blasts with a significant decrease of leukemia burden in peripheral blood by ~42% (p=0.0354), while there were no significant changes in bone marrow infiltration (n=5-6 mice per group). Ongoing experiments will further elucidate the anti-leukemic efficacy of daratumumab in combination with low-dose cytarabine. In summary, we found that targeting CD38 shows promising anti-leukemic activity with both cell-autonomous and microenvironment-mediated effects in AML. Together with tretinoin und putatively low-dose chemotherapy the efficacy of daratumumab in AML could be increased. This combination of well tolerated drugs could present a new option of niche-targeted therapies in AML. Disclosures Duehrsen: Janssen: Honoraria; Gilead: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Roche: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Research Funding.

In bone marrow malignancies, little is known about the fate of stromal cells after replacement of normal cells by neoplastic hematopoietic ones. In this study, fibroblasts from patients with acute myeloid leukemia or myelodysplastic syndromes exhibited a significantly lower ability to support hematopoiesis originating from co-cultured allogeneic CD34-positive cells than did fibroblasts from healthy marrow. Conversely, macrophages from acute myeloid leukemia marrow significantly enhanced the production of blood cells compared with control macrophages. Aberrant function was associated with consistent changes in the expression of genes involved in hematopoietic stem cell control, such as cytokines and regulators of the Wnt signaling pathway.