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  • 1
    Publication Date: 2015-05-06
    Description: Author(s): Lushuai Cao, Sven Krönke, Jan Stockhofe, Juliette Simonet, Klaus Sengstock, Dirk-Sören Lühmann, and Peter Schmelcher We investigate a binary mixture of bosonic atoms loaded into a state-dependent honeycomb lattice. For this system, the emergence of a so-called twisted-superfluid ground state was experimentally observed in Soltan-Panahi et al. [ Nat. Phys. 8 , 71 (2012) ]. Theoretically, the origin of this effect is n... [Phys. Rev. A 91, 043639] Published Thu Apr 30, 2015
    Keywords: Matter waves and collective properties of cold atoms and molecules
    Print ISSN: 1050-2947
    Electronic ISSN: 1094-1622
    Topics: Physics
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  • 2
    Publication Date: 2018-11-29
    Description: Introduction Recently, progress has been made in the treatment of patients with higher risk myelodysplastic syndromes (HR MDS) and acute myeloid leukemia (AML). Nevertheless, patients failing hypomethylating agents (HMA) have a dismal prognosis and very limited treatment options. Targeting CD123 on leukemic stem cells (LSC) is one promising approach in MDS and AML. Talacotuzumab (TAL, JNJ-56022473) is an IgG1 monoclonal antibody targeting CD123 preferentially via antibody-dependent cellular cytotoxicity (ADCC) mediated by natural killer cells (NKs). Aim The SAMBA trial, a phase II study of the German and French MDS study groups within the EMSCO network assessed the overall hematological response rate after 3 months of single agent TAL treatment in AML or HR MDS patients failing hypomethylating agents (HMAs). Methods TAL was given IV at a dose of 9 mg/kg once every two weeks for a total of 6 infusions, responders received up to 20 additional infusions. After the first 3 months, overall hematological response rate (either CR, PR, marrow-CR, HI, SD) was evaluated by bone marrow biopsy. The study was accompanied by an immune monitoring via flow cytometric analysis to investigate the distribution of T- and NK cells in peripheral blood (PB) and bone marrow (BM) at the time of screening and during therapy in comparison with healthy, age-matched controls. Results 24 patients (19 AML and 5 HR MDS) with a median age of 77 (range 71-90) years, who either failed to achieve complete- (CR), partial response (PR), hematological improvement (HI) or relapsed after HMA therapy were included in the study. After TAL administration, 14 patients could be assessed for response after 4 infusions and 10 patients after 6 infusions. The overall response rate (ORR) was 20.8% including 1 complete remission (CRi), 1 patient with hematologic improvement (HI-E) and additionally 3 patients with disease stabilization. The median duration of response in these patients was 3 months (range 3-14 months). Two patients are still on treatment, one patient despite losing objective response (14 months) and one patient with disease stabilization (13 months). The median overall survival for the entire cohort of patients was 3.2 months (range 0.4-11.2 months). In 10 patients (41.6%), therapy with TAL resulted in grade 3/4 infusion related side effects (pneumonia, n=1; infusion-related reaction, n=8; septic shock, n=1). Before treatment initiation, patients had lower levels of CD56dim NK-cells in PB (82% vs. 89% of NK-cells; p=0.069) expressing significantly more inhibiting NK-cell receptors like KIR2DL2 (8.8% vs. 3.2% of NK-cells; p
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
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  • 3
    Publication Date: 2014-12-06
    Description: Lenalidomide is a derivative of thalidomide, a drug developed in the 1950s as a sedative and treatment for morning sickness that became infamous for causing limb deformations (phocomelia) and other birth defects when used by pregnant women. Following the discovery in the 1990s that thalidomide inhibits the release of tumor necrosis factor (TNF) and blocks angiogenesis, researchers began studying thalidomide in other diseases, including cancer. Thalidomide demonstrated high in vitro activity in multiple myeloma and high response rates in clinical trials, leading to its accelerated approval by the FDA in 2006. In addition to the direct antiproliferative effects on multiple myeloma cells, thalidomide and its more potent derivatives, lenalidomide and pomalidomide, have pleiotropic effects on immune cells and are therefore called immunomodulatory drugs (IMiDs). IMiDs enhance the release of interleukin-2 (IL-2) and interferon-γ (IFN-γ) from activated T cells, inhibit the immunosuppressive activity of regulatory T cells, and increase natural killer (NK) cell-mediated cytotoxicity. In peripheral blood monocytes (PBMCs) IMiDs inhibit the release of TNF and other cytokines including interleukin-6 (IL-6), a critical growth factor for multiple myeloma cells. Recently, cereblon (CRBN) was identified as the common primary target for all IMiDs. CRBN forms an E3 ubiquitin ligase together with DNA damage-binding protein 1 (DDB1), cullin 4A (CUL4A), and regulators of cullins (ROC1) CRBN-CRL4. Interaction with this enzymatic complex has been shown to be essential for most properties of IMiDs including teratogenicity, antiproliferative effects in multiple myeloma and some of the immunomodulatory properties. More recently, it was demonstrated that lenalidomide and its analogues activate the CRBN-CRL4 E3 ligase to ubiquitinate and degrade two members of the Ikaros family of zinc finger transcription factors: Ikaros (IKZF1) and Aiolos (IKZF3). IKZF1 and IKZF3 are key regulators in lymphopoiesis and essential for lymphoid progenitor differentiation into effector cells. While IKZF1 and IKZF3 deletions and loss of function mutations are frequent in acute lymphoblastic leukemia, mature B-cell lymphomas like multiple myeloma and chronic lymphocytic leukemia have high IKZF1 and IKZF3 expression. Inactivation of IKZF1 and IKZF3 results in growth inhibition in multiple myeloma. Conversely, over-expression of IKZF1 or IKZF3 confers lenalidomide resistance, demonstrating that degradation of IKZF1 and IKZF3 is responsible for the direct cytotoxic effects of lenalidomide in multiple myeloma. One of the transcriptional targets of IKZF1 and IKZF3 is interferon regulatory factor 4 (IRF4), a transcription factor that is essential for proliferation and survival of multiple myeloma cells that is down-regulated after lenalidomide-induced degradation of IKZF1 and IKZF3. At the IL-2 locus, IKZF3 is a transcriptional repressor that is de-repressed after lenalidomide-induced degradation of IKZF3; explaining one of the immunomodulatory properties of lenalidomide. While IKZF1 and IKZF3 degradation is likely involved in the other effects of lenalidomide on T cell subsets and NK cells, it is unlikely that this accounts for all of its properties. Limb deformations, for instance, do not occur in mice with germline genetic inactivation of IKZF1 or IKZF3. Similarly, it is unlikely that degradation of the lymphoid transcription factors IKZF1 and IKZF3 accounts for the specific activity of lenalidomide in myelodysplastic syndrome with chromosome 5q deletion. Since most of these effects have been shown to depend on CRBN, it is conceivable that they result from lenalidomide-induced alteration of other substrates of the CRBN-CRL4 E3 ubiquitin ligase. Future studies aiming to identify the substrates responsible for each of the biological effects of IMiDs could enable the development of more specific drugs that modify ubiquitination of different sets of proteins with fewer side effects. Disclosures No relevant conflicts of interest to declare.
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  • 4
    Publication Date: 2020-08-18
    Description: Monitoring of measurable residual disease (MRD) provides prognostic information in patients with Nucleophosmin1 mutated (NPM1mut) acute myeloid leukemia (AML) and represents a powerful tool to evaluate treatment effects within clinical trials. We determined NPM1mut transcript levels (TL) by RQ-PCR and evaluated the prognostic impact of NPM1mut MRD and the effect of gemtuzumab ozogamicin (GO) on NPM1mut TL and the cumulative incidence of relapse (CIR) in patients with NPM1mut AML enrolled in the randomized phase III AMLSG 09-09 trial. 3733 bone marrow (BM) and 3793 peripheral blood (PB) samples from 469 patients were analyzed. NPM1mut TL log10 reduction ≥3 and achievement of MRD negativity in BM and PB were significantly associated with a lower CIR rate, after two treatment cycles and at end of treatment (EOT). In multivariate analyses, MRD positivity consistently revealed as poor prognostic factor in BM and PB. With regard to treatment effect, the median NPM1mut TL were significantly lower in the GO-Arm across all treatment cycles, resulting in a significantly higher proportion of patients achieving MRD negativity at EOT (56% vs 41%; P=.01). The betterreduction of NPM1mut TL after two treatment cycles in MRD-positive patients by the addition of GO led to a significantly lower CIR rate (4-year CIR 29.3% vs 45.7%, P=.009). In conclusion, the addition of GO to intensive chemotherapy in NPM1mut AML resulted in a significantly better reduction of NPM1mut TL across all treatment cycles leading to a significantly lower relapse rate. The AMLSG 09-09 trial was registered at www.clinicaltrials.gov as #NCT00893399.
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  • 5
    Publication Date: 2018-11-29
    Description: Background: BCMA, a member of the TNF receptor family, is expressed on MM and plasma cells. AMG 420, formerly BI 836909, binds BCMA on tumor cells and plasma cells and CD3 on T cells, resulting in T-cell mediated lysis of BCMA+ cells. Objectives of this study of AMG 420 in patients with R/R MM included assessing safety and tolerability and anti-tumor activity per IMWG 2006. Methods: This is a FIH phase I dose escalation study (NCT02514239) of 6-week cycles of AMG 420 (1 cycle=4 weeks continuous IV infusion, 2 weeks off). Single-patient cohorts [0.2-1.6 µg/day (d)] were followed by cohorts of 3-6 patients (3.2-800 µg/d). Eligible patients had R/R MM and progression after ≥2 prior treatment lines (including proteasome inhibitor and immunomodulators); excluded were patients with plasma cell leukemia, extramedullary relapse, known central nervous system involvement, or prior allogeneic stem cell transplant. Treatment continued for up to 5 cycles or until disease progression (PD), start of new therapy, toxicity, withdrawal of consent, or investigator decision; 5 more cycles could be given per investigator for perceived benefit. MRD response was defined for this study as
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  • 6
    Publication Date: 2012-03-08
    Description: To identify cooperating lesions in core-binding factor acute myeloid leukemia, we performed single-nucleotide polymorphism-array analysis on 300 diagnostic and 41 relapse adult and pediatric leukemia samples. We identified a mean of 1.28 copy number alterations per case at diagnosis in both patient populations. Recurrent minimally deleted regions (MDRs) were identified at 7q36.1 (7.7%), 9q21.32 (5%), 11p13 (2.3%), and 17q11.2 (2%). Approximately one-half of the 7q deletions were detectable only by single-nucleotide polymorphism-array analysis because of their limited size. Sequence analysis of MLL3, contained within the 7q36.1 MDR, in 46 diagnostic samples revealed one truncating mutation in a leukemia lacking a 7q deletion. Recurrent focal gains were identified at 8q24.21 (4.7%) and 11q25 (1.7%), both containing a single noncoding RNA. Recurrent regions of copy-neutral loss-of-heterozygosity were identified at 1p (1%), 4q (0.7%), and 19p (0.7%), with known mutated cancer genes present in the minimally altered region of 1p (NRAS) and 4q (TET2). Analysis of relapse samples identified recurrent MDRs at 3q13.31 (12.2%), 5q (4.9%), and 17p (4.9%), with the 3q13.31 region containing only LSAMP, a putative tumor suppressor. Determining the role of these lesions in leukemogenesis and drug resistance should provide important insights into core-binding factor acute myeloid leukemia.
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  • 7
    Publication Date: 2013-11-15
    Description: Lenalidomide is a highly effective drug for the treatment of multiple myeloma and has activity in additional B cell lymphomas. Lenalidomide has been shown to bind the CRBN-DDB1 E3 ubiquitin ligase, but it is unknown how lenalidomide alters the activity of this enzyme complex, and how this leads to therapeutic efficacy.  We used a combination of quantitative proteomic approaches to demonstrate that lenalidomide acts by a novel mechanism of action for a therapeutic agent: in multiple myeloma cells, lenalidomide increases the binding of two substrates, IKZF1 (Ikaros) and IKZF3 (Aiolos), to the CRBN substrate adaptor; increases the ubiquitination of these substrates; and causes the targeted degradation of these transcription factors that are essential for the differentiation and survival of plasma cells including multiple myeloma cells. To identify targets of the CRBN-DDB1 ubiquitin ligase that are altered by lenalidomide, we applied SILAC (stable isotope labeling by amino acids in cell culture)-based quantitative mass spectrometry studies to globally assess changes in ubiquitination and proteome levels in the multiple myeloma cell line MM1S. Two members of the Ikaros transcription factor family, IKZF1 and IKZF3, were differentially ubiquitinated and decreased after lenalidomide treatment.  Subsequent validation experiments in various cell lines demonstrated that lenalidomide, thalidomide, and pomalidomide cause a decrease of endogenous and ectopically expressed IKZF1 and IKZF3 protein levels but not mRNA levels. Furthermore, we confirmed that IKZF1 and IKZF3 bind CRBN in the presence of lenalidomide, supporting CRBN’s role as a substrate adaptor. Consistent with this, shRNA mediated knockdown or overexpression of a CRBN mutant (CRBNYWAA) that does not bind lenalidomide abrogated lenalidomide’s effect on IKZF1 and IKZF3. Moreover, CRBN promoted IKZF3 ubiquitination in vitro in the presence of lenalidomide, demonstrating that it is an enzymatic substrate. Using deletion mutants of IKZF3 we identified a 58-amino-acid degron in the N-terminal zinc finger domain that is sufficient for lenalidomide-induced degradation. Based on sequence alignment of that region between lenalidomide responding Ikaros proteins IKZF1 and IKZF3 vs. non-responding IKZF2, IKZF4 and IKZF5 we substituted a single amino acid (IKZF3Q147H) that prevented binding of IKZF3 to CRBN and conferred resistance to lenalidomide induced degradation. IKZF1 and IKZF3 are essential transcription factors for terminal B cell differentiation. We evaluated the biological effects of IKZF1 and IKZF3 loss using shRNAs in a variety of cell lines. IKZF1 and IKZF3 specific shRNAs inhibited the growth of multiple myeloma cell lines while lenalidomide insensitive cell lines derived from other hematopoietic neoplasms were unaffected. Similarly, a dominant negative IKZF3 mutant resulted in growth inhibition of MM1S cells. In contrast, expression of IKZF3Q147Hconferred lenalidomide resistance to MM1S cells. Lenalidomide induces IL-2 expression and release in T cells. We found that lenalidomide induced a dose-dependent decrease of IKZF1 and IKZF3 protein levels in primary human T cells. Previous studies have shown that IKZF3 is a transcriptional repressor of IL-2. To further evaluate the effect of IKZF3 loss, we transduced primary human T cells with shRNAs targeting either IKZF3 or control. IL2 RNA levels increased 3.3 fold after lenalidomide treatment in T cells expressing control shRNAs. In contrast, the baseline IL2 RNA level in T cells transduced with IKZF3 specific shRNAs was 3.7 fold higher compared to controls and this effect could not be further stimulated by lenalidomide. In conclusion, selective targeting of two lymphoid transcription factors, IKZF1 and IKZF3, explains lenalidomide’s selective growth inhibition in multiple myeloma and likely other B cell lymphomas as well as its immunomodulatory effects in T cells. Furthermore, selective ubiquitination and degradation of specific targets provides a novel mechanism of therapeutic activity for proteins that are not otherwise amenable to small-molecule inhibition. Disclosures: Ebert: Celgene: Membership on an entity’s Board of Directors or advisory committees.
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  • 8
    Publication Date: 2015-12-03
    Description: Background: Mutations in the nucleophosmin (NPM1) gene represent one of the most common gene mutations in AML, and are considered a founder event in the pathogenesis of AML. Recently, we gained novel insights into clonal architecture and clonal evolution in 53 NPM1 mutated (NPM1mut) AML patients (pts). Here, we showed the highest stability for DNMT3A mutations (DNMT3Amut) suggesting that these mutations represent an early event in leukemogenesis as well as an increase in genomic complexity. Aims: To validate our previous results on clonal evolution in a larger cohort of NPM1mut AML pts and to define relapse specific mutation patterns. Methods: Paired samples at diagnosis and relapse from 129 NPM1mut AML pts were assessed for additional mutations by comprehensive mutation analysis (FLT3-ITD, FLT3-TKD, DNMT3A, IDH1/2, NRAS, ASXL1, TP53, MLL-PTD). In addition, 11 AML cases with loss of NPM1mut at the time of relapse and 12 cases with persisting NPM1mut were subjected to whole exome sequencing (WES). Results: At diagnosis, the incidence of concurrent gene mutations was as follows: FLT3-ITDmut 32% (40/126), FLT3-TKDmut 19% (22/118), DNMT3Amut 69% (78/113), NRASmut 19% (22/117), IDH1mut 21% (26/123) and IDH2mut 19% (22/118). None of the pts analyzed exhibited a TP53 (n=53), MLL-PTD (n=63) or ASXL1 (n=59) mutation. At relapse, a significant shift in the genetic pattern was found in 74 pts (57%). FLT3-ITDmut was lost in 10 pts and newly acquired in 24 pts,16 pts lost FLT3-TKDmut. DNMT3Amut was lost in 2 pts and gained in 1 pt. NRASmut was lost in 12 pts and gained in 4 pts. IDH1mut was lost in 3 pts and acquired in 4 pts, while IDH2mut was lost in 2 pts and gained in only one pt. ASXL1mut and TP53mut were gained in 2 and 1 pts, respectively; gain of MLL -PTDmut (n=4) was restricted to pts with loss of NPM1mut at the time of relapse. Based on these findings we calculated the following stabilities: FLT3-ITDmut 75%, FLT3-TKDmut 27%, DNMT3Amut 97%, NRASmut 45%, IDH1mut 88% and IDH2mut 91%, respectively. In total, 11 pts (9%) lost NPM1mut at relapse while DNMT3Amut was present in 9/11 pts at diagnosis and remained stable at relapse; 4/11 pts gained MLL-PTDmut, one pt ASXL1mut and 3 pts acquired RUNX1mut. By WES we observed a persistence of mutations known to be involved in clonal hematopoiesis, such as DNMT3A and TET2 mutations. These were usually seen during all analyzed time points (diagnosis, remission and relapse). In addition, we found distinct mutational patterns at the time of relapse compared to the time of diagnosis. For example, relapse- and diagnosis-specific mutations in NPM1mut loss cases were significantly enriched for different signaling pathways. Conclusions: 74 (57%) of 129 NPM1mut AML pts showed clonal evolution at the time of relapse. DNMT3Amut demonstrated the highest stability (97%) confirming our previous findings that DNMT3Amut constitutes an early event which persists in preleukemic hematopoietic stem cells. High-resolution sequencing of selected cases is ongoing and will further unravel the clonal hierarchy in NPM1mut AML. Those authors equally contributed to work: SKS, SC, LB and KD. Disclosures Heuser: Karyopharm: Research Funding.
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  • 9
    Publication Date: 2015-12-03
    Description: Background: Nucleophosmin (NPM1mut) mutations represent one of the most common gene mutations in acute myeloid leukaemia (AML) and can be used for monitoring minimal residual disease (MRD). In a former study, we could define clinical relevant check-points and a cut-off value to identify patients (pts) at high risk of relapse. Aims: To confirm our previous results on the clinical relevance of NPM1mut transcript levels (TL) in an extended cohort of younger AML pts (18 to 60 years) harbouring NPM1mut type A, B, C, D, JT, 4, QM, NM or KM, and to assess the impact of concurrent FLT3 internal tandem duplications (ITD) and DNMT3A (DNMT3Amut) mutations on NPM1mut TL kinetics. Methods: All pts were enrolled in one of four AMLSG [AMLHD98A (n=46; NCT00146120); AMLSG 07-04 (n=199; NCT00151242); AMLSG 09-09 (n=179; NCT00893399); AMLSG 16-10 (n=75; NCT01477606)] treatment trials. Treatment comprised double induction therapy (DI) with ICE (idarubicin, cytarabine, etoposide) with or without ATRA or gemtuzumab ozogamicin, or 1 cycle of daunorubicin and cytarabine followed by 1 to 4 cycles of high-dose cytarabine (n=292), autologous (n=19) or allogeneic stem cell transplantation (n=141). NPM1mut TL (ratio of NPM1mut/ABL1 transcripts x 104) were determined by RQ-PCR using TaqMan technology; the sensitivity of the assays was 10-5 to 10-6. DNMT3A and FLT3 -ITD (FLT3 -ITDmut) mutation status was assessed by standard PCR-based methods. Results: A total of 2835 samples from 499 NPM1mut pts were analysed at diagnosis (n=439), after each treatment cycle (n=1394) and during follow-up (FU) (n=1002). Peripheral blood (PB) samples were only included in the advanced FU period (defined as at least 12 months after completion of therapy). NPM1mut TL at diagnosis varied between 7.03 x103 and 2.38 x 107 (median 5.37 x 105). Pretreatment NPM1mut TL were not associated with clinical characteristics (e.g., age, WBC, BM blasts, FLT3 -ITDmut, DNMT3Amut) with the exception of LDH level (p=0.006) and did not impact event-free survival (EFS), relapse-free (RFS) and overall survival (OS). NPM1mut TL as log 10 transformed continuous variable at different time points during therapy were significantly associated with shorter remission duration (RD) and shorter OS. After DI therapy, the cumulative incidence of relapse (CIR) at 4 years was 10% for RQ-PCR-negative pts (n=41) versus 45% for RQ-PCR-positive pts (n=226) (p
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  • 10
    Publication Date: 2015-12-03
    Description: Background: The DNA methyltransferase 3A (DNMT3A) is one of the most frequent mutated genes in AML with a hot spot mutation at codon R882 in 80% of the DNMT3Amut cases. In most of the studies DNMT3Amut predicts for poor overall (OS) and relapse-free survival (RFS). Recently, DNMT3Amut have been associated with age-related clonal hematopoiesis, and they have been identified in early preleukemic stem cells. These findings suggest that DNMT3Amut represents an early event in leukemogenesis and may be part of the leukemia founder clone in most AMLs harboring a DNMT3Amut. We thought to address the question whether MRD monitoring in DNMT3Amut patients (pts) can be used for prognostic classification and risk stratification in these pts. Aims: We monitored MRD for the most common DNMT3Amut (DNMT3Amut -R882H, n=126 and -R882C, n=55) in a large cohort of adult AML pts entered on three AMLSG treatment trials [AML HD98A (n=14; NCT00146120), AMLSG 07-04 (n=86; NCT00151242), AMLSG 09-09 (n=81; NCT00893399)]. Methods: DNMT3Amut MRD monitoring was performed using a cDNA-based RQ-PCR-assay by TaqMan technology with a sensitivity between 10-3 and 10-4. MRD levels are reported as normalized values of DNMT3Amut transcripts per 104ABL1 transcripts (DNMT3Amut/104ABL1). Results: In total, 1,494 samples [bone marrow (BM), n=798; peripheral blood (PB), n=696] from 181 DNMT3Amut pts were analysed [diagnosis, n=287; during therapy, n=840; follow-up, n=367]. Median age of the patients was 50 years (range, 22 to 78); median BM DNMT3Amut transcript level (TL) at the time of diagnosis was 12690 (range, 1396-54280). There was no significant association of TL with presenting clinical characteristics, such as age, white blood cell count, platelet count, BM and PB blasts, lactate dehydrogenase, or with mutations in NPM1, FLT3 [ITD and TKD], CEBPA and cytogenetics. DNMT3Amut TL as log 10 transformed continuous variable and stratified by study did not impact OS (p=0.29), RFS (p=0.17) and EFS (p=0.28). Comparing TL after double induction (DI) did not show a significant difference between 13 patients without complete remission (CR) and 117 in CR (12983 and 12595, respectively; p=0.52). In Cox regression analyses, BM DNMT3Amut TL as log 10 transformed continuous variable during therapy did not impact the clinical endpoints death and relapse. In general, DNMT3Amut TL during therapy (after induction I, induction II, consolidation I and II) were significantly higher in BM than in PB (p=0.01; p=0.05; p=0.004; p=0.008, respectively). We observed the greatest TL reduction (one log) after induction I, whereas subsequent cycles of therapy did not significantly influence TL. To evaluate the impact of DNMT3Amut MRD monitoring with regard to the clinical endpoints OS, cumulative incidence of relapse (CIR) and remission duration (RD) after DI and after end of therapy (ET) we used different statistical approaches; all survival analyses were stratified by study. After DI and ET, only 8/90 and 4/88 BM samples became MRD negative. At these two time-points MRD positivity did not significantly impact OS (p=0.99; p=0.74), CIR (p=0.73; p=0.15) and RD (p=0.83; p=0.16). Next, we investigated the MRD DNMT3Amut log10-reduction (compared to levels at diagnosis) after DI and ET using the median as a cut-off. Again, we could not detect a significant correlation for pts with a higher TL reduction compared with pts with a lower TL reduction for OS and RD after DI and ET (p=0.83; p=0.30; p=0.04; p=0.21, respectively). Lastly, we evaluated the BM DNMT3Amut TL as 4 increasing equally sized intervals according to the quartiles of the distribution. There was no prognostic impact after DI on OS and RD (p=0.53; p=0.89) and ET (p=0.76; p=0.53). When combining PB and BM samples for the analyses we could not find significant changes in the results. Conclusion: In our study most pts had persistent DNMT3Amut TL with only a minority achieving MRD negativity, a finding that supports the presence of persistent clonal hematopoiesis in hematologic remission. Using different explorative approaches, DNMT3Amut TL did not impact clinical outcome neither during therapy nor during follow-up. Disclosures Horst: Gilead: Honoraria, Research Funding; Pfizer: Research Funding; MSD: Research Funding; Boehringer Ingleheim: Research Funding; Amgen: Honoraria, Research Funding. Schlenk:Arog: Honoraria, Research Funding; Boehringer-Ingelheim: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Teva: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees.
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