Cytogenetic Score Research Articles

First Single-Center Experience with Luspatercept Therapy in Low-Risk Myelodysplastic Syndrome (LR-MDS) Patients with Transfusion Dependence Refractory to Erythropoietin Therapy

Introduction: In the treatment of low-risk myelodysplastic syndromes (MDS) patients, anemia is the predominant problem. A recent breakthrough in the therapy of anemia in low-risk MDS patients are drugs involved in TGFβ pathway blockade. Luspatercept is a recombinant fusion protein derived from human activin receptor type IIB. It binds TGFβ superfamily ligands and inhibits the SMAD2/3 pathway leading to potentiation of red cell line differentiation and proliferation. Luspatercept was approved last year by the FDA and EMEA in the treatment of anemic low-risk MDS patients with ring sideroblasts (MDS-RS-MLD, MDS-RS-SLD) and/or SF3B1 mutated patients who are not eligible for erythropoiesis-stimulating agents (ESA) or for patients who failed on this therapy. Luspatercept showed high clinical activity for the treatment of anemia in the phase 2 trial (PACE-MDS) and subsequently in the phase 3 trial (MEDALIST). It has led to transfusion independence (TI) in about 40 % of patients. Methods: From January 2021 to July 2022, 27 patients were treated with luspatercept at the hematology department of Charles University Hospital in Prague, Czech Republic. The median age of the patients was 77 years (range 57-89) with a male to female ratio 17:10. WHO 2016 diagnosis were: MDS-RS-MLD (N = 23) and MDS/MPN-RS-T (N = 4). Median of IPSS-R was 2.5 (range 1-4). Median of IPSS-R cytogenetic score scaled from 0-2 with the median of 1. Median follow-up was 7.8 months (range 1-38). Luspatercept was administered in subcutaneous injections once every 3 weeks with an initial dose of 1 mg/kg. Dose escalation was done according to the level of response to 1.33 and 1.75 mg/kg. The median number of cycles administered was 7 (2-17). Transfusion dependency before luspatercept initiation ranged from 2 transfusion units (TU)/8 weeks to 12 TU/8 weeks, 11 patients had low transfusion burden (LTB), 16 high transfusion burden (HTB). Baseline erythropoietin (EPO) level was 374 IU/l in average (range 150-770) and ferritin level was 1307 μg/l in average (range 234-3832). 9 patients received chelation therapy. 22 patients were tested for SF3B1 mutation with 21 positive results (95.5 %) using Sanger sequencing (N = 3) or NGS approach (N = 18). Isolated mutation of SF3B1 was present in 8 patients (44 %). The most frequent mutations besides SF3B1 were TET2 (N = 8; 44 %), ASXL1 (N = 3; 17 %), DNMT3A and RUNX1 (N = 2; 11 %). Average mutations count per one patient was 1.7 (range 0-5). We did not observe any TP53 mutation. Results: There were 24 evaluable patients in terms of response. Thus far 11 (45 %) patients have responded by achieving TI, 5 (20 %) patients have had a reduction in transfusion dependence (HI, according to IWG criteria 2006), 8 (33 %) patients have not responded. One patient progressed to the higher risk MDS, and one transformed to acute myeloid leukemia. Median duration of response was 7.4 months (range: 0.7-31.8). Median number of cycles to achieve response was 4. Eleven patients responded to the basic dose 1 mg/kg, 2 additional patients on the dose 1.33 mg/kg and 2 more on the dose 1.75 mg/kg. There were differences in response according to transfusion burden, in LTB group achieved TI 8 patients and HI 1 patient, in HTB group we observed TI in 3 patients and HI in 4 patients. In 9 patients, we added ESA to luspatercept therapy, as they act both at different levels of erythropoiesis, which led to the improvement of response in 5 cases. In general, patients with lower initial baseline EPO level were better responders. We did not observe decrease in ferritin level during therapy. There was no significant effect of mutation burden on patient's OS, although patients with single mutated SF3B1 achieved better ORR (75 %), than patients bearing mutations in multiple genes (ORR = 40 %). There were no adverse effects of Grade II or more. Conclusion: In conclusion, luspatercept is certainly the next major step in the treatment of anemia in MDS patients. The advantage of the drug is very good tolerance and easy administration. We observed better responses in patients bearing single mutation in SF3B1, patients with LTB and lower initial baseline EPO levels. The higher response rate in our follow-up may be influenced by the combination with ESA and rapid dose escalation. This work was supported by the following grants: grant AZV 2021-2024 NU21-08-00312, Grant AZV 2019-2023 NV19-08-00144, UNCE/MED/016

MDS-406 Prognostic Implication of the Molecular Profiles of Patients With Hypocellular Myelodysplastic Syndrome

Hypocellular myelodysplastic syndrome (hMDS) is a subset of MDS that has not been fully characterized. This study aimed to better identify the clinical characteristics and molecular profile of hMDS and study the prognostic impact of mutations in hMDS. We conducted a retrospective review of patients with newly diagnosed MDS in a single tertiary cancer center registry from 2010 to 2021. Of 1,899 patients with MDS, 176 (10%) patients had hMDS. The median follow-up period was 19.5 months. hMDS patients were more likely to be younger and have therapy-related disease and more thrombocytopenic and neutropenic than normo/hypercellular MDS (non-hMDS). All other clinical characteristics were comparable. The distributions of IPSS-R cytogenetic scores (≥3, or <3) were comparable. hMDS patients had similar overall survival (OS) to non-hMDS (median 28.3 vs. 29.0 months) or AML transformation rates (23% vs. 19%). These findings were maintained after multivariate adjustment. Hypocellularity did not affect survival in either de novo or t-MDS. We further analyzed 1,352 (71%) pts with mutation data available. Patients with hMDS had less frequent ASXL1, RUNX1, TET2, or IDH1 mutations, whereas the frequency of TP53 and RAS pathway mutations were comparable. In de novo MDS, hMDS patients had less frequent RUNX1, SRSF2, or TET2 mutations. In t-MDS, hMDS pts had less frequent TP53 or U2AF1 mutations. The survival of hMDS can be stratified by IPSS-R with some overlaps. In hMDS, mutations in the RAS pathway or TP53 were associated with inferior OS, whereas TET2 mutations correlated with superior OS. Based on the mutation data, patients were stratified into 3 groups: (1) with TET2 mutations, (2) with TP53 or RAS pathway mutations without TET2 mutations, and (3) without TET2/TP53/RAS mutations. The TET2 mutant group showed marginally better mOS (HR 0.50, P=0.081), and the TP53/RAS pathway group showed inferior mOS (HR 2.74, P=.005) compared with the group without TET2/TP53/RAS pathway mutation. Patients with hMDS had similar outcomes to patients with non-hMDS but exhibit distinct molecular profiles; hMDS had less frequent driver mutations commonly seen in non-hMDS. The integration of molecular profiles into risk stratification in hMDS could be a study of interest.

High-resolution structural variant profiling of myelodysplastic syndromes by optical genome mapping uncovers cryptic aberrations of prognostic and therapeutic significance

Chromosome banding analysis (CBA) remains the standard-of-care for structural variant (SV) assessment in MDS. Optical genome mapping (OGM) is a novel, non-sequencing-based technique for high-resolution genome-wide SV profiling (SVP). We explored the clinical value of SVP by OGM in 101 consecutive, newly diagnosed MDS patients from a single-center, who underwent standard-of-care cytogenetic and targeted NGS studies. OGM detected 383 clinically significant, recurrent and novel SVs. Of these, 224 (51%) SVs, seen across 34% of patients, were cryptic by CBA (included rearrangements involving MECOM, NUP98::PRRX2, KMT2A partial tandem duplications among others). SVP decreased the proportion of normal karyotype by 16%, identified complex genomes (17%), chromothripsis (6%) and generated informative results in both patients with insufficient metaphases. Precise gene/exon-level mapping allowed assessment of clinically relevant biomarkers (TP53 allele status, KMT2A-PTD) without additional testing. SV data was complementary to NGS. When applied in retrospect, OGM results changed the comprehensive cytogenetic scoring system (CCSS) and R-IPSS risk-groups in 21% and 17% patients respectively with an improved prediction of prognosis. By multivariate analysis, CCSS by OGM only (not CBA), TP53 mutation and BM blasts independently predicted survival. This is the first and largest study reporting the value of combined SVP and NGS for MDS prognostication.

P770: A COMPARATIVE STUDY OF LEUKEMIC TRANSFORMATION IN THERAPY-RELATED AND DE NOVO MYELODYSPLASTIC SYNDROME AFTER HYPOMETHYLATING AGENT FAILURE

Background: Therapy-related myelodysplastic syndrome (t-MDS) is subset of myelodysplastic syndrome (MDS), known for having dismal survival outcomes. The majority of patients (pts) with t-MDS have similar clinical courses with de novo MDS patients after hypomethylating agent failure (HMA-F) that often results in transformation to acute myeloid leukemia (AML). Aims: We conducted a study to identify unique clinicopathologic features of t-AML from t-MDS compared to secondary AML (sAML) from de novo MDS after HMA-F. Methods: We identified sAML patients after HMA-F from all untreated MDS pts in a tertiary cancer center registry from 2017-2021. Clinical characteristics and pathologic data including cytogenetic (CG) and next generation sequencing (NGS) information were collected at the time of MDS diagnosis (dx), HMA-F, and AML dx. Results: 71 (48%) MDS pts with AML transformation after HMA-F were included in the study with a median follow-up time of 15.4 months (mo). At the time of MDS dx, 31 (43%) pts had t-MDS: 97%, 58% and 29% had a history of chemotherapy, radiation, and prior stem cell transplant (SCT), respectively. t-MDS patients were more likely to present with age<65 (48% vs. 28%, p=0.070) and thrombocytopenia (33,000 vs. 75,500, p=0.004) when compared to de novo MDS pts. The majority of t-MDS pts had very high risk disease by IPSS-R (67% vs. 39%, p=0.031), while de novo MDS pts frequently had high risk disease (50% vs. 20%, p=0.013). 90% of t-MDS pts had adverse CG (IPSS-R CG score 3-4) at MDS dx, compared to 46% in de novo MDS pts (p=0.004). NGS at MDS dx showed more frequent TP53 mutations in t-MDS than in de novo MDS (73% vs 36%, p=0.003). Interestingly, ASXL1 (36% vs. 1%, p=0.001), RUNX1 (9% vs. 0%, p=0.004), STAG2 (21% vs. 0%, p=0.013), TET2 (13% vs. 0%, p<0.001), and SRSF2 (18% vs. 0%, p=0.027) were more frequently found in de novo MDS (Table). t-MDS had worse overall survival (OS) from MDS dx (HR 1.82, p=0.026). The median OS from MDS dx was 19.4 mo and 14.3 mo in de novo MDS and t-MDS, respectively. The number of HMA cycles received before HMA-F was 6 (range: 1-13) in t-MDS and 5 (range: 1-23) in de novo MDS. At the time of HMA-F, t-MDS pts presented with more anemia (p=0.005) and thrombocytopenia (p=0.064). The number of CG clones were similar, but the number of CG abnormalities were higher in t-MDS pts (p=0.025). Among pts with subsequent AML transformation after HMA-F, the median time from HMA-F to AML was 1.5 mo in t-MDS to AML, compared to 4.6 mo in de novo MDS to AML. At time of AML dx, 48 (68%) pts had mutation panels available. All TP53 mutation status stayed the same in t-MDS pts at the time of MDS and AML dx. Other changes in mutations were shown in Table. Though the median OS from AML transformation was short in all pts, t-MDS pts had inferior outcomes (2.4 mo vs. 5.0 mo, HR 1.70, p=0.043). The initial response rate to salvage therapy was comparable between t-MDS and de novo MDS after AML transformation (50% and 56%, p=0.761), but more pts underwent SCT with de novo MDS compared to t-MDS (10% vs. 3%, p=0.383). Image:Summary/Conclusion: Transformation to AML after HMA-F results in poor outcomes, but pts with t-MDS have worse survival with distinct CG and mutation profiles. Further understanding of the pathogenesis of AML transformation in both t-MDS and de novo MDS after HMA-F is warranted with improved therapy options an area of unmet need.

Genomic Subgroups Impact Post-Transplant Survival in Patients with Myelodysplastic Syndrome: A CIBMTR Analysis

BackgroundMyelodysplastic syndromes (MDS) are clonal stem cell malignancies characterized by cytopenia, inefficient hematopoiesis, dysplasia in one or more myeloid cell lineages and increased risk of development of acute myeloid leukemia. It has been well appreciated that genomic alterations play a key role in MDS pathogenesis. The Revised International Prognostic Scoring System (IPSS-R) algorithm is commonly used to predict overall survival but may fail to recapitulate reliable prognostic information at the individual patient level, especially at the time of hematopoietic cell transplantation (HCT). Current World Health Organization (WHO) classification includes MDS with isolated 5q deletion as the only genetically defined category. Comprehensive analysis of recurrent genomic features by unsupervised clustering empowers discovery of potential prognostic molecular signatures.MethodsUsing whole blood samples obtained from 494 MDS patients at the time of HCT, we conducted whole-genome sequencing (WGS) and somatic variant processing via a custom analytic pipeline based on OCTOPUS and a set of annotation databases. Multiple filters allowed for selection and fine-tuning of criteria, including removal of variants with Gnomad allele frequency above 10x10 -06, removal of noncoding variants in low complexity and repetitive regions, those with no functional indications from ANNOVAR annotations, CADD conservative score under 15, and absence in HGMD or COSMIC databases. Highly annotated clinical data, including cytogenetic abnormalities at the latest time point prior to HCT, were obtained from CIBMTR forms. K-means clustering was applied to recurrent mutations and cytogenetic abnormalities to identify clinically relevant genomic subtypes. The optimal cluster number was determined by Gap-status algorithm. Statistics of clinical characteristics were compared among different genomic subgroups by Chi-squared test for categorical variables and Mann-Whitney U test for continuous variables. Overall survival association tests were conducted by Cox multivariate models. Relapse and transplant-related risk were performed by competing risk analysis using Fine-Gray models. Models were adjusted for patient-, disease-, and HCT-related factors.ResultsThe somatic genomic landscape in our MDS cohort was examined for the total count of recurrent mutations at the sample level and gene level. Among 53 recurrently mutated genes in 257 of 494 MDS cases, TP53, TET2, RUNX1, DNMT3A, and ASXL1 were the most frequently mutated genes in our MDS cohort. Based on k-means clustering of the recurrent mutational and cytogenetic data, we detected five clusters that stratified our MDS patient cohort, including one reference cluster with no recurrent somatic mutations or cytogenetic abnormalities. Compared to the reference subgroup, significantly higher cytogenetic scores and IPSS-R scores were observed in genomic clusters with TP53 mutations (cytogenetic score: P=3.42E-07*; IPSS-R score: P= 2.38E-10*) and cytogenetic abnormalities del5q, or tri8p (cytogenetic score: P= 2.38E-10*; IPSS-R score: P=0.09) , or mono7 (cytogenetic score: P=3.29E-13*; IPSS-R score: P=1.38E-05*) (data not shown). Cox multivariate models revealed that genomic clusters with TP53 and del5q mutations (P<0.001*) or tri8p (P=0.02*) mutations have strong associations with post-transplant overall survival outcome (Figure 1A). Furthermore, competing risk analysis confirmed significantly higher risk of relapse in genomic subgroups with TP53 and del5q mutations in the reduced intensity conditioning regimen setting (P=0.01) (Figure 1B), while significantly higher risk of transplant-related mortality was found in the genomic subgroup with tri8p in the myeloablative conditioning regimen setting (P=0.03) (Figure 1C).ConclusionOur study suggests that molecular signatures from MDS patient genomes at HCT may provide an independent prognosis of post-transplant survival. Additionally, our data suggests that the choice of regimen intensity could be informed by knowledge of the individual genomic signature of a given MDS patient. [Display omitted] DisclosuresSaber: Govt. COI: Other.

High-Throughput Characterization of Cytogenomic Heterogeneity of MDS Using High-Resolution Optical Genome Mapping

IntroductionIntroduction of next-generation sequencing has defined the somatic mutational landscape in MDS. Comprehensive high-throughput structural variant profiling (SVP) is as important as mutation profiling in characterizing MDS clonal architecture since these large genomic aberrations have already shown to be critical for diagnosis and risk-stratification of MDS. A subset (MECOM, KMT2A rearrangements) are therapeutic targets in clinical trials. At this time, technical advances in SVP for copy number alterations (CNAs) and fusions have not been congruent with mutation profiling due to the inability of short-read (150bp) NGS to detect SVs. Currently available long-read (10-20Kbp) and whole genome sequencing cannot detect all SVs due to the presence of repeat sequences. Hence, conventional karyotyping (CK) remains the gold standard. Optical genome mapping (OGM) is a novel single-platform technique that measures ultra-long-range sequence patterns (>300Kbp), thereby unaffected by repeat sequences, enabling unbiased evaluation of all types of SVs at a high resolution. Here, we performed comprehensive SVP and mutation profiling in a large well-characterized cohort of MDS.MethodsWe selected samples with available fresh/frozen BM cells from consecutive treatment-naïve MDS pts who also underwent standard-of-care tests (CK, FISH, targeted 81-gene NGS for mutations). For OGM, ultra-high-molecular-weight-DNA was extracted, followed by labeling, linearization and imaging of DNA (Saphyr, Bionano) [median coverage:>300X]. The results were analyzed using de novo (>500 bp), rare variant (>5000 bp) and copy number (>500,000 bp) pipelines. The data was compared against 200 healthy controls to exclude common germline SVs. Clinical significance of the SVs was determined based on the location/overlap with the coding region of myeloid malignancy associated genes. The detection sensitivity was 10%.ResultsThere were 76 treatment naïve MDS patients. Baseline characteristics, comprehensive cytogenetic scoring system (CCSS) and R-IPPS risk categories and somatic mutations are in Fig 1.OGM identified all clonal abnormalities detected by CK [CNAs, inversions, inter/intra-chromosomal translocations, dicentric, complex derivative chromosomes]. Precise mapping of SVs by OGM at gene-level allowed determining the status of clinically informative biomarkers such as TET2, MECOM, TP53 and KMT2A, without the need for confirmatory assays. Detailed gene-level characterization of different SVs included KMT2A-ELL [t(11;19)] in MDS with WT1 mut, t(9;11) with SYTL2 fusion (and not KMT2A), der(1;7) leading to del(7q) in MDS with GATA2 mut/IDH2 mutand t(1;3)(p36;q21) rearrangements with potential PRDM16 disruption in SF3B1 mut/RUNX1 mutMDS, among others. Using OGM, we mapped the sequence patterns in both samples with IM with high level of confidence.Additionally, OGM identified 23 cryptic, clinically significant SVs in 14 (18%) of 76 pts. These included deletions of TET2, KMT2A, and del(5q), KMT2A amplification in MDS with FLT3-ITD/DNMT3A mut/RAS mut, NUP98-PRRX2, MECOM rearrangement in TET mut mutated NK-MDS. In addition, there were SVs of uncertain significance: duplications of chr1 (PDE41P), deletions of chr21 (involving RUNX1), chr2 (DNMT3A, ASXL2), chr12 (ETV6) and chr22 (EP300) and der(16)t(12;16)(q21.1;q12.1). These cryptic SVs were noted across all R-IPSS risk categories (highest yield in very-low and low R-IPSS) and across all cytogenetic risk-groups (very-good to very-poor).In complex karyotype setting, OGM could resolve the markers and additional genetic material, and in most cases, showed a much higher the degree of complexity within the genome than was apparent by CK. Four pts showed SV patterns typical of chromothripsis/chromoplexy.The median number of mutations per pt was 1 (0-6). When compared to mutation subsets, cryptic SVs were only identified in pts with ≤3 mutations. Majority represented either MDS with TP53 mut (6, 29%) or SF3B1 mut/TET mut (deletions of TET2, KMT2A, NOTCH1 and EP300 genes).ConclusionsUnbiased, high-throughput whole genome SVP revealed cryptic, clinically significant SVs in ~18% of MDS pts. OGM is a single-platform cytogenomic tool that can facilitate SVP at a gene-level resolution. This study provides strong support for further validation in expanded cohorts to guide clinical implementation and integration of SVP for routine work-up. [Display omitted] DisclosuresWei: Daiichi Sanko: Research Funding. Kantarjian: Ipsen Pharmaceuticals: Honoraria; Amgen: Honoraria, Research Funding; Astellas Health: Honoraria; Astra Zeneca: Honoraria; AbbVie: Honoraria, Research Funding; KAHR Medical Ltd: Honoraria; NOVA Research: Honoraria; Ascentage: Research Funding; Aptitude Health: Honoraria; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Jazz: Research Funding; Immunogen: Research Funding; Daiichi-Sankyo: Research Funding; BMS: Research Funding; Precision Biosciences: Honoraria; Taiho Pharmaceutical Canada: Honoraria.

Lymphocytic Infiltrate and p53 Protein Expression as Predictive Markers of Response and Outcome in Myelodysplastic Syndromes Treated with Azacitidine.

High-risk Myelodysplastic syndromes (MDS) represent therapeutical challenges and are usually managed with hypomethylating agents such as azacitidine. Given the lack of data in the literature concerning azacitidine effects on bone marrow, we retrospectively analyzed 57 high-risk MDS cases in order to identify any changes induced by azacitidine therapy or relevant correlations between therapy response and pre- or post-treatment features. Azacitidine treatment had no significant impact on bone marrow cellularity or morphological dysplastic features. On the contrary, although not statistically significant, we observed a slight decrease in CD34+ and CD117+ blasts and p53+ precursors after treatment. Moreover, pre-treatment IPSS-R cytogenetic score (p = 0.004), lymphocytic infiltrate (p = 0.017) and p53+ elements (p = 0.001) correlated with AML progression; pre-treatment lymphocytic infiltrate was also linked to better response to therapy (p = 0.004), suggesting an anti-tumoral role of bone marrow microenvironment. Post-treatment blast count impacted negatively on overall survival (p = 0.035) and risk of leukemic progression (p = 0.04), while both post-treatment lymphocytic infiltrate and p53+ elements showed significant correlation with treatment response (p = 0.004 and p = 0.003 respectively). Higher post-treatment p53+ elements correlated also with risk of leukemic progression (p = 0.013). Our results suggest the possible role of lymphocytic infiltrate and p53+ elements as predictive markers in MDS treated with azacitidine, disclosing new chapters in the understanding of MDS evolution and treatment.

P-048: Clinical application of the weighted cytogenetic scoring system in Multiple Myeloma

<h3>Methods</h3> Utility of the weighted cytogenetic scoring system (wCSS) was studied in 250 myeloma patients with complete data on high-risk FISH [t(4;14), t(14;6), del(1p32), amp(1q21) and del(17p)] and lactate dehydrogenase (LDH). <h3>Results</h3> All patients had bortezomib-based induction, with triplet induction in 88%. Sixty-four (26.2%) had ISS I, 75 (30.7%) stage II and 105 (43%) stage III MM. Fifty-two patients (21.2%) had t(4;14), 25 (10%) del(17p), 26 (10.4%) del(1p32) and 83 (66.8%) amp(1q21). Fifty-nine (23.9%) had wCSS=0, 144 (58.3%) wCSS>0 to ≤1 and 44 (17.8%) wCSS>1. Median survival were 168, 80 and 37 months for wCSS=0, >0 to ≤1, and wCSS>1 respectively (p=9.4 x 10-7). wCSS>1, of which 56.8% had del(17p), was not associated with gender, isotype, ISS III, high LDH or post-induction CR. <h3>Conclusion</h3> The adverse impact of wCSS>1was partially mitigated by ASCT. Therefore, wCSS is valid in our real-life cohort of myeloma uniform receiving a bortezomib-based triplet induction even without trisomy data.

Overview of myelodysplastic syndrome in Baghdad, Iraq- clinical picture and outcome

Background: Myelodysplastic syndromes (MDS) can represent a challenge in diagnosis and treatment because of heterogeneous presentation, unpredictable response to variable measures with propensity for leukemic transformation. Aim of study: To review MDS Iraqi patients in term of presentation, risk stratification and treatment options and to assess outcome of different treatment options in term of response criteria, quality of life and progression. Patients and method: a hospital based study conducted over a period of 21 months from January 2018 till October 2019 in different hematology centers in Baghdad. Any patient with primary or therapy related MDS diagnosed were enrolled in this study. Each patient stratified into different risk groups when applying cytogenetic versus non cytogenetic scoring systems, the therapeutic options for every patient. They observed for their response to different therapeutic modalities and any evidence of progression. Results: Mean age at diagnosis for MDS was 58.7± Anemia was the most common presenting symptom representing 68.4% of patients. MDS with excess blasts-II is forming 28.8%. Majority of patients categorized as intermediate risk group. Hypomethylating agents used for 50% of MDS patients while 32.1% received best available therapy. Those on HMA achieve partial remission in 7.1%, 25.2% reached to stable disease, hematological improvement in 25.2%. Death outcome in 21.6 with a mean survival is 7.7 months. Disease progression in 10.8%, 7.2% showed leukemic transformation. Conclusion: Iraqi MDS patients present at younger age with advanced manifestation that needs standard risk stratification. The non-cytogenetic score systems can't be of equivalent application even low resources circumstances.

A Novel CD16xCD33 Bispecific Killer Cell Engager (BiKE) Mediates a Double Hit For Natural Killer (NK) Cells To Target CD33+ Myelodysplastic Syndrome (MDS) Cells and Myeloid Derived Suppressor Cells (MDSCs) At All Disease Stages

MDS is a clonal heterogeneous stem cell disorder identified by pancytopenia that frequently progresses to acute myeloid leukemia (AML). The only curative treatment is hematopoietic cell transplantation (HCT), but many patients are ineligible due to advanced age and comorbidities. New therapeutic strategies are urgently needed to reduce disease burden and improve overall survival. Studies of NK cell function from MDS patients have shown diminished natural cytotoxicity against K562 targets. These NK cell defects have been ascribed to abnormalities in expression and function of the NK cell activating receptors NKG2D, NKp30, NKp46 and DNAM-1. However, the properties of the potent activating receptor CD16 (FcgRIII) and its potential for mediating targeted immunotherapy remain unexplored in MDS. Frozen pre-transplant samples from 67 MDS patients (age 19-74 years, Median=47) receiving unrelated HCT were obtained from the research sample repository of the National Marrow Donor Program and were compared to normal volunteers. NK cell degranulation, cytotoxicity and cytokine production were evaluated using published methods. We focused on CD16-induced NK cell function using a bispecific killer cell engager generated to target CD16 along with the myeloid differentiation antigen CD33 (CD16xCD33 BiKE). CD16 expression on total CD56+ MDS-NK cells was significantly lower compared to normal donors (MDS vs. normal: 63 ± 3% (n=67) vs. 89 ± 2% (n=20); p < 0.0001). However, reverse-antibody dependent cell-mediated cytotoxicity (R-ADCC) assays revealed no significant differences in CD107a (46 ± 5% (n=16) vs. 46 ± 3% (n=12)), IFN-g (6 ± 1% vs. 10 ± 2%) or TNF-a (9 ± 2% vs. 6% ± 1%) production when resting MDS-NK cells were triggered with an agonistic CD16 mAb, indicating MDS-NK cell function triggered through CD16 is intact. To evaluate the therapeutic potential of targeting CD16 in MDS patients, resting MDS-mononuclear cells were coated with 10mg/mL of the CD16xCD33 BiKE and co-cultured for 4 hours with the CD33+ target cell line HL-60. MDS-NK cell CD107a (CD16xCD33 BiKE vs. no reagent: 42 ± 2% (n=62) vs. 22 ± 1% (n=20); p < 0.0001), IFN-g (15 ± 1% vs. 3 ± 1%; p < 0.0001) and TNF-a (13 ± 1% vs. 3 ± 1%; p < 0.0001) production was significantly increased compared to the no reagent and scFv CD16 controls. Moreover, in the absence of HL-60 targets, MDS-NK cells treated with the CD16xCD33 BiKE targeted endogenous CD33+ targets, significantly enhancing degranulation (37 ± 2% vs. 17 ± 1%; p < 0.0001), IFN-g (4 ± 1% vs. 2% ± 1%; p < 0.01) and TNF-a (5 ± 1% vs. 2 ± 1%; p < 0.01) production. Recent data have shown an increase in the frequency of MDSCs, phenotypically defined as CD33+/CD11b+/CD14-/HLA-DRlo/-, during oncogenesis and in the presence of inflammatory cytokines. Indeed, in our MDS patient cohort, the frequency of MDSCs of total viable mononuclear cells was significantly higher compared to normal donors (6 ± 1% (n=64) vs. 0.1 ± 0.02% (n=18), respectively; p < 0.0001) (figure). Furthermore, CD16xCD33 BiKE-treated resting NK cells from normal donors co-cultured with cytokine-induced MDSCs generated from normal PBMCs in a 51Cr-release cytotoxicity assay successfully targeted and lysed MDSCs (CD16xCD33 BiKE vs. no reagent (E:T = 20:1): 63 ± 5% vs. 7 ± 2% [p < 0.0001, n=4]; (E:T = 6.6:1): 35 ± 3% vs. 4 ± 1% [p < 0.0001]). CD107a (48 ± 2% (n=6) vs. 4 ± 1% (n=3); p < 0.0001), IFN-g (8 ± 1% vs. 1 ± 1%; p < 0.0001) and TNF-a (8 ± 1% vs. 1 ± 1%; p < 0.0001) production was also significantly increased against MDSC targets in the presence of the CD16xCD33 BiKE, demonstrating its ability to facilitate killing of both the CD33+ MDS clone and an immune suppressor cell population. Lastly, analysis of MDS patient karyotypes in correlation with CD16xCD33 BiKE-induced MDS-NK cell CD107a, IFN-g and TNF-a production did not reveal any significant differences between favorable, intermediate or poor international prognostic scoring system (IPSS) cytogenetic scores, further demonstrating the therapeutic potential of the CD16xCD33 BiKE to induce optimal MDS-NK cell function against CD33+ targets despite disease heterogeneity. In summary, our data suggest that the CD16xCD33 BiKE may function not only against CD33+ MDS targets themselves, but also against MDSCs. This double hit approach may protect against MDS progression/transformation to AML through immune targeting and may improve blood counts by targeting MDS-MDSCs that contribute to ineffective hematopoiesis. [Display omitted] Disclosures:No relesvant conflicts of interest to declare.

Fluorescence in Situ Hybridization (FISH) Frequently Upstages Risk Estimates for MDS Patients with Normal Metaphase Karyotype

IntroductionThe international prognostic scoring system (IPSS) and its revised version (R-IPSS) are the most widely used clinical models for MDS risk stratification. Both models account for cytogenetic abnormalities captured by G-banding metaphase karyotyping. Among MDS patients, 50-60% will have a normal karyotype. MDS FISH panels are commonly applied to supplement cytogenetics. In small subsets of patients with normal karyotype, MDS FISH may detect cytogenetic abnormalities not resolved by metaphase karyotype. The utility of MDS FISH panel in refining IPSS or R-IPSS cytogenetic risk score among those patients is not known. We explored the impact of FISH in upstaging MDS patients with a normal karyotype and its prognostic value if incorporated into IPSS or R-IPSS cytogenetic risk score.MethodsWe identified patients with normal karyotype by G-banding who had cytogenetic abnormalities detected by an MDS FISH panel. The MDS FISH panel included probes for deletion (del(5)), del(7), del (20), trisomy 8 and del 17p. IPSS and R-IPSS was calculated based on karyotype as the standard recommendation and then recalculated according to cytogenetic abnormalities detected by the MDS FISH panel (FISH_IPSS and FISH_R-IPSS). Median overall survival (OS) was calculated from time of diagnosis using Kaplan-Meier estimates.ResultsAmong 1600 patients in our MDS database with normal karyotype by G-banding, 53 patients (3%) had a cytogenetic abnormality detected by FISH. The cytogenetic abnormalities detected included del(7)/monosomy 7 in 25/53 patients (47%), del(5q)/monosomy 5 in 22/53 patients (42%), trisomy 8 in 14/53 (26%), del(20q) in 10/52 (19%), and 17p deletion in 1/10 (10%).According to IPSS, 15 patients (33%) were classified as low risk, 18 patients (40%) as intermediate-1 (int-1), 9 patients (20%) int-2, and 3 patients (7%) as high risk. Table-1 summarizes restaging using FISH_IPSS where 53% of low risk IPSS were upstaged to int-1, 56% of int-1 upstaged to int-2, and 78% of int-2 upstaged to high risk.By conventional R-IPSS, 18 patients (40%) were very low risk, 11 patients (24%) low risk, 12 patients (26%) intermediate risk, and 4 patients (9%) high risk. Upon restaging using FISH_R-IPSS (Table 2), 61% of very low risk patients, all low risk patients, 92% of intermediate risk patients, and 50% of high risk patients with FISH abnormalities were upstaged.Among patients with low risk IPSS, median OS was 64 months (mo) for those low risk by FISH_IPSS and 61 mo for those upstaged to int-1 by FISH_IPSS. For patients with int-1 risk IPSS, median OS was 26 month for those int-1 by FISH_IPSS and 24.8 mo for those upstaged to int-2 risk by FISH_IPSS. Finally, for patients with int-2 risk IPSS, median OS was 30 mo for those classified as int-2 and 22 mo for those upstaged by FISH_IPSS.Based on R-IPSS the median OS was 64, 24, 25 and 19 mo for very low, low, int, and high risk groups. Using FISH_RIPSS the median OS was 64, 61,30,21,22 mo respectively for very low, low, int, high and very high risk groups (p.003). Based on R-IPSS cytogenetic risk category all those patient were classified as good risk given normal karyotype with median OS of 30 mo. Based on FISH data if cytogenetic score was re-calculated accordingly, 16 patients remained good risk, 22 patients intermediate risk, and 14 patients high risk. The median OS was 30, 30 and 22 mo respectively.ConclusionsFISH detected cytogenetic abnormalities in a small number of patients with normal karyotype by G-banding, which altered risk score assignment by IPSS and R-IPSS in a significant subset of positive patients. [Display omitted] DisclosuresKomrokji:Celgene: Honoraria; Novartis: Honoraria, Speakers Bureau. Sallman:Celgene: Research Funding. Padron:Incyte: Honoraria, Research Funding. Sweet:Ariad: Consultancy, Speakers Bureau; Karyopharm: Consultancy, Research Funding; Otsuka: Consultancy; Incyte: Research Funding; Pfizer: Consultancy; Novartis Pharmaceuticals: Consultancy, Speakers Bureau. Lancet:Pfizer: Other: Institutional research funding, Research Funding; Boehringer Ingelheim: Consultancy; Novartis: Consultancy; Celgene: Consultancy; Erytech: Consultancy; BioSight: Consultancy; Bio-Path Holdings: Consultancy; Janssen: Consultancy; Jazz Pharmaceuticals: Consultancy.

Does a Change in IPSS-R between Diagnosis and Transplant Have an Impact on Transplant Outcome in Patients with MDS? a Retrospective Analysis from the EBMT Chronic Malignancies Working Party

IPSS-R is a well established prognostic factor for transplant outcome in patients with MDS, irrespective whether it is assessed at diagnosis or at transplant. However it is unclear how a change in IPSS-R, e.g. by reducing bone marrow blasts through therapy, would potentially affect transplant results. In particular the decision to treat patients before transplant or perform an upfront allogeneic transplantation can so far not be based on evidence. We did a registry search based in the MDS quality initiative conducted by EBMT to identify transplanted patients with MDS and sufficient data to calculate IPSS-R at diagnosis and before transplant. The search was limited to patients reveiving a first allogeneic stem cell transplantation in the period 2005 -2018. 1482 patients were identified. Median age at alloHCT was 59 (interquartile range 51-64) years, 60% were male. Donors were related in 36%, graft source was PBSC in 85% of cases. Conditioning was standard dose in 33% and reduced intensity in 67%. IPSS-R both at diagnosis and at transplant had a significant impact on OS and RFS after alloHCT. To investigate the effect of a change in IPSS-R between diagnosis and transplant we constructed 3 subgroups: stable IPSS-R, improved IPSS-R, worsened IPSS-R. A change in IPSS-R was noted in 77.5% of patients with prior chemotherapy, 72% with prior HMA and 59.8% of untreated patients. Univariate analysis showed no significant difference in OS or RFS in patients with stable IPSS-R compared to improved or worsened IPSS-R. In patients treated with chemotherapy before transplant OS and RFS was significantly worse with worsened IPSS-R, while this effect was not found in patient treated with hypomethylating agents (HMA) or untreated patients. The same analysis was performed regarding the difference in bone marrow blasts and the cytogenetics score: OS and RFS after transplant were significantly worse with increased blasts (p=0.04 and p=0.001) and a worsened cytogenetic score before transplant (both p&amp;lt;0.001). While worsened IPSS-R, blast count or cytogenetic score had a negative impact on transplant outcome, the improvement of these parameters showed no positive effect on either OS or RFS in the total cohort or in the subgroups of untreated patients, after chemotherapy or after HMA treatment. In this retrospective analysis from a large cohort of patients with MDS we found that worsening of IPSS-R, blast count or cytogenetic score had a negative prognostic impact in chemotherapy-treated patients, while only worsened blast count and cytogenetics were significant negative factors in HMA-treated or untreated patients. Conversely we did not find a positive effect of improved IPSS-R, decreased blasts or improved cytogenetics in any of the subgroups of treated or untreated patients. Thus for MDS patients receiving an allogeneic transplantation our results provide no clear signal that prior therapy is able to improve transplant outcome. Disclosures Scheid: Novartis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; BMS: Honoraria; Amgen: Honoraria; Takeda: Honoraria, Research Funding. Blaise:Jazz Pharmaceuticals: Honoraria. Chevallier:Incyte Corporation: Honoraria. Yakoub-Agha:Celgene: Honoraria; Novartis: Honoraria; Gilead/Kite: Honoraria, Other: travel support; Janssen: Honoraria; Jazz Pharmaceuticals: Honoraria.

Azacitidine and Lenalidomide in Higher-Risk Myelodysplastic Syndromes. Long-Term Results of a Randomized Phase II Multicenter Study and Impact of Cytogenetic Scores and Mutational Status on Long-Lasting Responses

Azacitidine and Lenalidomide in Higher-Risk Myelodysplastic Syndromes. Long-Term Results of a Randomized Phase II Multicenter Study and Impact of Cytogenetic Scores and Mutational Status on Long-Lasting Responses

MDS-141: The Prognostic Impact of Cytogenetic Scores in Patients with Higher-Risk Myelodysplastic Syndrome Treated with Venetoclax and Azacitidine in a Phase 1 Study

Background/Aims: Venetoclax (Ven), a selective oral BCL-2 inhibitor, has shown synergy with hypomethylating agents (HMAs) such as Azacitidine (Aza), in treatment of higher-risk myelodysplastic syndrome (HR)-MDS. We evaluate prognostic impact of cytogenetic categories of revised International Prognostic Scoring System (IPSS-R) among HR-MDS patients treated with Ven+Aza. Methods: This study enrolled patients age ≥ 18 yrs, untreated for MDS, with IPSS score of ≥1.5, bone marrow blasts Results: As of 8/21/2019, 57 patients (75% male, median age 71yrs) received Ven+Aza combination. According to IPSS-R classification, at baseline, 9 (16%) patients were at intermediate risk, 13 (24%) at high risk, and 33 (60%) at very high risk. Cytogenetic risk based on IPSS-R: 2 (4%) were very good, 18 (32%) good, 8 (15%) intermediate, 13 (23%) poor, and 15 (26%) very poor. Ten genes were mutated in >10% of patients, including poor prognosis conferring TP53, RUNX1, TET2, ASXL1, SRSF2, STAG2, and IDH1/2. Median follow-up time was 8.9 months. Complete remission (CR)+marrow CR (mCR) rates by IPSS-R cytogenetic risk were: very good 100% (2/2), good 94% (17/18), intermediate 63% (5/8), poor 62% (8/13), and very poor 73% (11/15). Median with 95% confidence interval (CI) in progression-free survival (PFS) was 6.7 (0.7–not estimable), 9.3 (3.2–not estimable), and 9.5 months (2.7–9.5) in the intermediate, poor, and very-poor risk groups, respectively, and not reached in the good and very-good risk groups. Median overall survival (OS) in patients with very poor risk was 16.2 months (2.0–16.2). The estimated 12-month OS were 53%, 88%, and 100% in the poor, intermediate, and good risk groups, respectively. Conclusion: This preliminary analysis shows promising efficacy of Ven+Aza combination treatment across all IPSS-R cytogenetic risk categories and suggests prognostic relevance of the IPSS-R cytogenetic scoring system. Abstract was previously published at EHA25.

Genomic context and TP53 allele frequency define clinical outcomes in TP53-mutated myelodysplastic syndromes

AbstractTP53 mutations are associated with adverse outcomes and shorter response to hypomethylating agents (HMAs) in myelodysplastic syndrome (MDS). Limited data have evaluated the impact of the type, number, and patterns of TP53 mutations in response outcomes and prognosis of MDS. We evaluated the clinicopathologic characteristics, outcomes, and response to therapy of 261 patients with MDS and TP53 mutations. Median age was 68 years (range, 18-80 years). A total of 217 patients (83%) had a complex karyotype. TP53 mutations were detected at a median variant allele frequency (VAF) of 0.39 (range, 0.01-0.94). TP53 deletion was associated with lower overall response rate (ORR) (odds ratio, 0.3; P = .021), and lower TP53 VAF correlated with higher ORR to HMAs. Increase in TP53 VAF at the time of transformation was observed in 13 patients (61%), and previously undetectable mutations were observed in 15 patients (65%). TP53 VAF was associated with worse prognosis (hazard ratio, 1.02 per 1% VAF increase; 95% confidence interval, 1.01-1.03; P < .001). Integration of TP53 VAF and karyotypic complexity identified prognostic subgroups within TP53-mutant MDS. We developed a multivariable model for overall survival that included the revised International Prognostic Scoring System (IPSS-R) categories and TP53 VAF. Total score for each patient was calculated as follows: VAF TP53 + 13 × IPSS-R blast score + 16 × IPSS-R cytogenetic score + 28 × IPSS-R hemoglobin score + 46 × IPSS-R platelet score. Use of this model identified 4 prognostic subgroups with median survival times of not reached, 42.2, 21.9, and 9.2 months. These data suggest that outcomes of patients with TP53-mutated MDS are heterogeneous and that transformation may be driven not only by TP53 but also by other factors.

Aspacytarabine (BST-236) Is Safe and Efficacious As a Single-Agent, First-Line Therapy for Patients with Acute Myeloid Leukemia Unfit for Standard Chemotherapy. Integrated Results from a Phase 1/2a and an Ongoing Phase 2b

Introduction: Aspacytarabine (BST-236) is a prodrug of cytarabine, a backbone of acute myeloid leukemia (AML) therapy. Due to its unique pharmacokinetics and metabolism, treatment with aspacytarabine evades peak exposure to free cytarabine, which reduces non-hematological toxicity and enables delivery of high-dose cytarabine also to patients unfit for standard therapy. Data from a completed phase 1/2a and an ongoing phase 2b studies in AML patients unfit for standard therapy, including patients with AML secondary to therapy and myelodysplastic syndrome (MDS) with prior exposure to hypomethylating agents (HMA), demonstrate promising single-agent efficacy and safety of aspacytarabine as a potential first-line AML treatment for this challenging population. Aims: To evaluate the efficacy and safety of aspacytarabine in AML patients unfit for standard induction therapy. Methods: A completed phase 1/2a study and an ongoing phase 2b study evaluate the efficacy and safety of aspacytarabine as a single-agent therapeutic for AML. The phase 1/2a, dose-escalation study enrolled newly-diagnosed patients unfit for standard therapy and patients with relapsed/refractory AML. Patients were treated with 0.3-6 g/m2/d aspacytarabine in 6 dose-escalating cohorts. The ongoing multi-center phase 2b study expands the subgroup of newly-diagnosed AML patients unfit for standard therapy, to evaluate the efficacy and safety of aspacytarabine as a first-line therapy for this population. Secondary AML patients, treated with HMA, chemotherapy, or radiotherapy for a prior condition, are allowed. Patients in the phase 2b study are treated with the selected aspacytarabine dose of 4.5 g/m2/d, containing approximately 3 g/m2/d of cytarabine. Each aspacytarabine treatment course (induction and consolidation) consists of 6 1-hour daily intravenous infusions. Results: To date, 34 AML patients, median age 76 years, received at least 1 dose of aspacytarabine, including 30 patients unfit for standard induction therapy due to age or comorbidities. Overall, 25 patients completed 1 course of aspacytarabine, 4 patients completed 2 courses, 1 patient completed 3 courses, and 1 patient completed 4 courses of aspacytarabine. Three patients (in the phase 1/2a study) did not complete the first course. Aspacytarabine was safe and well-tolerated in repeated-course administration, including in older and unfit patients. Adverse events included mainly hematological "on-target" events with no drug-related mucositis or cerebellar toxicity. Twenty-one patients were newly-diagnosed with AML, either de novo or secondary to MDS or therapy. The patient population was characterized by older age (median 76 years, range 67-88 years), and the majority (67%) of patients had secondary AML, including 10 patients (48%) who were previously treated with HMA (median of 10 courses) or radiotherapy. The median baseline bone marrow blast percentage of this population was 75, and 43% and 48% had intermediate or adverse European LeukemiaNet (ELN) cytogenetic score, respectively. Despite these poor-prognostic characteristics, the 30-day mortality rate in the group of patients receiving ≥4.5 g/m2/d aspacytarabine was 7%. The combined complete remission (CR) rate of all doses was 33%, including 1 patient reaching a CR with partial platelet recovery (CRp). The CR rate in patients treated with at least 4.5 g/m2/d aspacytarabine is 36%, with median time for complete hematological recovery of 27 days (range 21-30) following induction and consolidation. Notably, among the 7 patients who reached a CR/CRp (median age 77), 3 secondary AML patients reached a CR, including 2 patients with prior exposure to HMA (5 and 10 courses) and 1 with prior exposure to radiotherapy (Table 1). Duration of response and overall survival follow up is ongoing and will be presented at the meeting. Conclusions: The accumulating clinical data suggest that aspacytarabine is safe and efficacious for the treatment of AML patients who are unfit for standard induction therapy, including patients with prior exposure to HMA, which may establish aspacytarabine as a new therapeutic backbone for AML, either as a single agent or in combination with targeted therapy. Disclosures Altman: Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Glycomimetics: Consultancy, Honoraria, Other: Data Safety and Monitoring Committee; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Biosight: Other: US Lead; Novartis: Consultancy; Agios: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Cancer Expert Now: Consultancy; France Foundation: Speakers Bureau; prIME Oncology: Speakers Bureau; PeerView: Speakers Bureau; Theradex: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Luger:Seattle Genetics: Research Funding; Pfizer: Honoraria; Onconova: Research Funding; Kura: Research Funding; Jazz: Honoraria; Genetech: Research Funding; Daichi Sankyo: Honoraria; Cyslacel: Research Funding; Celgene: Research Funding; Biosight: Research Funding; Ariad: Research Funding; Agios: Honoraria. Kota:Takeda: Honoraria; Xcenda: Honoraria; Novartis: Honoraria; Amgen: Honoraria; Pfizer: Honoraria. Flaishon:BioSight Ltd.: Employment. Tessler:BioSight Ltd.: Employment. Gengrinovitch:BioSight Ltd.: Employment. Ben Yakar:BioSight Ltd.: Employment. Rowe:BioSight: Consultancy.

Conditioning Regimen Intensity May Affect Outcome in MDS Patients Undergoing Allogeneic Stem Cell Transplantation, Depending on MDS Subgroup

Allogeneic stem cell transplantation (SCT) is a potentially curative treatment for MDS. Besides the innate heterogeneity of MDS, intensity of the conditioning regimen (myeloablative (MAC) versus reduced intensity/non-myeloablative (RIC)), specific agents used in conditioning, donor and source of stem cells and GVHD prevention regimens further influence outcomes. We sought to determine how conditioning regimens influenced MDS subgroup cohort outcomes. We retrospectively analyzed outcomes of 107 MDS patients (63 male and 44 females) with median age 61.8 (17-73 years) who underwent allogeneic SCT at our institution between 2008 and 2017. For the purposes of this report, patients were grouped according to WHO classification into non-RAEB (RCMD, RA, RARS RCUD or 5q deletion, n=49) and RAEB (RAEB1 and RAEB2, n=58) categories. Median time from MDS diagnosis to transplantation was 139 days (20-3175). No patients were in complete remission (CR) at time of SCT. Allogeneic donor types were matched related, matched unrelated, haplo-identical and cord blood in 30, 65, 10 and 2 patients, respectively. Stem cell source was peripheral blood (91 patients) and bone marrow in 14. Forty patients (median age 52.2 (17-61) years) underwent MAC and 67 (median age 63.7 (23-73) years) RIC. Twelve patients died within 100 days of transplantation, 3 due to disease progression, 5 to acute GVHD, and 4 to other transplant-related causes. Median overall survival (OS) for all 107 patients was 1.3 years with 54%, 47% and 40% alive at 1, 2 and at 5 years. OS was slightly higher in patients undergoing RIC with OS of 57%, 48% and 40% (median 1.532 years) versus 50%, 40% and 38% with MAC (median 0.92 years) at the same time points (p&gt;0.1). Median OS of the 49 patients with non-RAEB and 58 patients with RAEB MDS was 3.01 years versus 0.92 years (p&gt;0.1). GVHD was the most frequent cause of death (46%), followed by relapse/progression (28%), infection (14%) and other (12%). Of 29 patients undergoing RIC with non-RAEB MDS, median OS was 3.78 years while for 38 RAEB patients it was 1.17 years (p&gt;0.1). See table for OS according to conditioning regimen and WHO classification. For MAC, in 20 non-RAEB patients median OS was 2.2 years while the median OS was 0.69 years for 20 RAEB patients (p&gt;0.1). CR after SCT was achieved in 57 patients (53%), 33 receiving RIC (CR 49.2%) and 24 receiving MAC (CR 60%). Seven patients subsequently relapsed, 4 RIC and 3 MAC. Of the non-RAEB patients achieving CR, median OS in the 16 patients treated with 111 RIC was not reached and in 14 patients receiving MAC, median OS was 3.75 years (p&gt;0.1). For the 27 RAEB patients achieving CR, median OS was 4.4 years in 17 patients treated with RIC versus not reached in 10 patients treated with MAC. Overall, death in non-RAEB patients occurred in 26/49 (53%) compared to 38/58 (66%) RAEB patients and in 40/67 (59%) patients undergoing RIC versus 25/40 (63%) MAC patients (p&gt;0.5). The hematopoietic transplant comorbidity index did not predict OS outcomes in these MDS patients (p&gt;0.1) and the cytogenetic score according to the IPSS-R "very good -very poor" groups indicated no differences in OS in the non-RAEB patients but in RAEB patients significant differences according to the cytogenetic score was evident (P&lt;0.01). Conclusions: In this retrospective analysis of MDS patients undergoing allogeneic SCT, achieving CR led to improved survival. In non-RAEB MDS patients achieving CR, OS was similar irrespective of conditioning intensity (RIC or MAC). Furthermore, outcomes did not differ in RAEB patients who achieved CR according to intensity of conditioning regimen. However, those receiving MAC had not reached median OS at 5 years. The outcomes in this analysis indicate that improvement in the incidence of deaths due to GVHD would likely have the greatest impact in improving survival in MDS patients undergoing allogeneic transplantation. Table Disclosures Abhyankar: Therakos: Other: Consulting, Speakers Bureau; Incyte: Speakers Bureau. Lin:Jazz Pharmaceuticals: Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees. Yacoub:Incyte: Consultancy, Speakers Bureau. Ganguly:Kite Pharma: Honoraria, Other: Advisory Board; Seattle Genetics: Speakers Bureau; Janssen: Honoraria, Other: Advisory Board; Daiichi Sankyo: Research Funding. McGuirk:Pluristem Ltd: Research Funding; Gamida Cell: Research Funding; Kite Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bellicum Pharmaceuticals: Research Funding; Astellas: Research Funding; Fresenius Biotech: Research Funding; Novartis: Research Funding; Juno Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; ArticulateScience LLC: Other: Assistance with manuscript preparation.

TP53 State Dictates Genome Stability, Clinical Presentation and Outcomes in Myelodysplastic Syndromes

TP53 State Dictates Genome Stability, Clinical Presentation and Outcomes in Myelodysplastic Syndromes

Cytogenomic array detects a subset of myelodysplastic syndrome with increased risk that is invisible to conventional karyotype.

Conventional karyotyping is essential standard practice in the initial evaluation of myelodysplastic syndrome (MDS) and is the most impactful single component of the Revised International Prognostic Scoring System (IPSS-R). While single nucleotide polymorphism array (SNP-A) has demonstrated the ability to detect chromosomal defects with greater sensitivity than conventional karyotype, widespread adoption is limited by the unknown additional prognostic impact of SNP-A analysis. Here, we investigate the significance of additional SNP-A abnormalities in the setting of MDS and demonstrate differences in survival of patients with additional abnormalities, even those initially characterized as relatively lower risk either by cytogenetic score or IPSS-R. Our findings identify specific abnormalities, particularly KMT2A partial tandem duplication, that are invisible to conventional karyotype and potentially contribute to the poor prognosis of MDS patients. Furthermore, these results demonstrate the added value of SNP-A analysis in identifying patients who may benefit from more aggressive therapy, particularly those who would otherwise be classified into lower risk categories.

A novel non-invasive monitoring assay of 5-azacitidine efficacy using global DNA methylation of peripheral blood in myelodysplastic syndrome.

Purpose: Monitoring response and resistance to 5-azacitidine (AZA) is essential when treating patients with myelodysplastic syndrome (MDS). To quantify methylated DNA not only in the promoter region but also in the gene body, we established a single-molecule methylation assay (SMMA).Patients and methods: We first investigated the methylation extent (expressed as methylation index [MI]) by SMMA among 28 MDS and 6 post-MDS acute myeloid leukemia patients. We then analyzed the MI in 13 AZA-treated patients.Results: Whole-blood DNA from all 34 patients had low MI values compared with healthy volunteers (P<0.0001). DNA hypomethylation in MDS patients was more evident in neutrophils (P=0.0008) than in peripheral mononuclear cells (P=0.0713). No consistent pattern of genome-wide DNA hypomethylation was found among MDS subtypes or revised International Prognostic Scoring System (IPSS-R) categories; however, we found that the MI was significantly increased for patients at very high risk who were separated by the new cytogenetic scoring system for IPSS-R (P=0.0398). There was no significant difference in MI before AZA, regardless of the response to AZA (P=0.8689); however, sequential measurement of MI in peripheral blood demonstrated that AZA non-responders did not have normalized MI at the time of next course of AZA (P=0.0352).Conclusion: Our results suggest that sequential SMMA of peripheral blood after AZA may represent a non-invasive monitoring marker for AZA efficacy in MDS patients.