AML Transformation Research Articles

Evaluation of Lenalidomide (LEN) Vs Placebo in Non-Transfusion Dependent Low Risk Del(5q) MDS Patients. Final Results of Sintra-REV Phase III International Multicenter Clinical Trial

Background: Most MDS patients with del(5q) develop RBC TD or need treatment for symptomatic anemia early after diagnosis (median time to transfusion/treatment of 20 months, López Cadenas et al abstract 3180 ASH 2016). Lenalidomide (LEN) is a reference treatment in MDS-del(5q) but approved in many countries only when RBC-TD occurs. No randomized trials before Sintra-Rev had explored the role of LEN in the setting of non-TD anemia in del(5q) MDS. Interim analysis of Sintra-Rev (Lopez Cadenas et al abstract 536 ASH 2020) showed that early treatment with LEN prolongs the Transfusion Free survival (p=0.021), with a high percentage of erythroid (72%) and cytogenetic responses (80%) among LEN treated patients. Material: Sintra-Rev is a phase III multicenter trial in low-risk MDS-del(5q) patients with anemia without TD. Patients were randomized (2:1) in a double-blind design to LEN (5mg/day continuously) vs placebo for 2 years of treatment and 2y of follow-up. The primary endpoint was the time to TD. 2º endpoints included erythroid (HI-E), cytogenetic response (CyR), overall survival (OS), event free survival (EFS), time to AML and mutational analysis (NGS). Here, we report the final results of this clinical trial once all patients have completed their participation in the study and after extending follow-up to explore long-term AML transformation and/or death. Results: Main clinical characteristics of the 61 patients (ITT population) included are summarized in Table 1: In 32% of patients no somatic mutation was identified (NGS), compared to 36% with one mutation and 32% with ≥ 2 mutations. TP53mut was present at diagnosis in 17.2% and 27.8% of LEN and Placebo patients (p=0.48). The evaluable population included 54 patients (7 patients were excluded due either to screening failure [1 pat] or failure to complete at least 12w of treatment [6 pat] without progression disease). Median time on treatment was 66 weeks (3-121), 95w in the LEN arm and 42w in the placebo arm (p=0.392). Forty-seven percent patients in the LEN arm successfully completed the study compared to 33% in the placebo arm. After a median follow up of 60.6 months (Q1 32.3-Q3 73.9), median OS was 101.2m (95CI 54.8 - 147.7) without statistically significant differences between the two treatment groups (p=0.529). In relation to the primary objective of this trial, Time to TD (ITT-pop) was 66.3mo (95CI 37 - 95.5) for LEN patients and 11.6mo for the placebo arm (HR 0.414 95CI 0.196- 0.875, p=0.021) (Figure 1). EFS was 60.2mo (CI95% 45-74) for LEN compared to 20.2mo (CI95% 0 - 51) for Placebo (p=0.058) in the ITT Population (HR 0.46, CI95% 0.2 - 0.948, p=0.035 in the evaluable population). HI-E was observed in 70% of LEN patients (ITT-pop) compared to 0% in the placebo arm (p<0.001). Median Hemoglobin improvement in responders was 2.7 g/dL. Eighty percent of LEN patients (ITT-pop) achieved a cytogenetic response (CyR) (87.5% complete CyR) compared to 0% of patients receiving placebo (p<0.001). AML evolution was identified in 6/40 (15%) and 5/21 (23.8%) for LEN and Placebo patients respectively (p=0.488). NGS analysis during follow up showed the mean number of mutations per patient to be reduced in the LEN arm at week 12 (0,84 mutations compared to 1,21 previous to treatment; (p<0.01)), while no differences were found in the Placebo group (p=0.59). In addition, no differences were identified regarding clonal evolution for LEN and Placebo patients during study follow-up. Fifty-eight patients developed at least one adverse event (AE) during the trial (no differences between the LEN and placebo arm), related to the drug 86.8% in the LEN and 33.3% in the placebo arm, respectively (p<0.001). Severe AEs were the same as those collected in the interim analysis (abstract 536 ASH 2020). Conclusions: This final analysis of the Sintra-Rev clinical trial confirms that low dose LEN (5 mg), in anemic non-TD low risk MDS del(5q) patients, prolongs time to TD from the beginning of treatment (66.6 mo vs 11.6mo), improves Hb levels (70% of ER) and induces good quality clonal responses (80% CyR), ie potentially more responses than in historical series of MDS del(5q) treated with LEN at time of TD, with a manageable safety profile, and no increased progression rate or clonal evolution. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

SF3B1 mutated MDS: Blast count, genetic co-abnormalities and their impact on classification and prognosis

Recently, MDS with mutated SF3B1 and blast count <5% was proposed as distinct entity with favorable prognosis by the international working group for the prognosis of MDS (IWG-PM), the 5th edition of the WHO classification and the International Consensus Classification. To further characterize this entity with respect to the genomic landscape, AML transformation rate and clinical outcome, we analyzed 734 MDS patients by whole genome sequencing. SF3B1 mutations were identified in 31% (n = 231), most frequently accompanied by TET2 mutations (29%). 144/231 (62%) SF3B1mut samples fulfilled entity criteria proposed by IWG-PM (SF3B1ent). These cases were associated with longer survival, lower AML transformation rate, normal karyotypes and harbored less accompanying mutations compared to SF3B1mut samples not falling into the proposed SF3B1 entity (SF3B1nent). Of SF3B1mut cases 7% (15/231; SF3B1ent: 3/144 [2%]; SF3B1nent: 12/87 [14%]) progressed to AML compared to 15% SF3B1 wild-type patients (75/503). Of these 15 SF3B1mut cases, 10 (67%) showed RUNX1 mutations at MDS or AML stage. Multivariate analysis revealed that del(5q) and RUNX1 mutations were independent negative prognostic factors for overall survival, while blast count >5% was not. In conclusion, SF3B1mut MDS has a favorable prognosis independent of blast count if karyotype and RUNX1 mutations are considered.

MDS-529 The Prognostic Value of the Endothelial Activation and Stress Index (EASIX) Score, Platelet-to-Lymphocyte Ratio (PLR), and Neutrophil-to-Lymphocyte (NLR) in Myelodysplastic Syndrome Patients in Jordan after Adjusting for IPSS-R Risk Groups

The findings of the current study are expected to expand the available prognostic systems for myelodysplastic syndromes (MDS). To determine the value of endothelial activation and stress index (EASIX) score, neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) measured at diagnosis in the prognosis of MDS patients. This is an observational study in which registry data was collected prospectively between January 2007 and September 2021. The data were reviewed and analyzed retrospectively. The patients recruited in this study were followed up for an average of 3.59 years. The data collection procedure took place at Jordan University Hospital, one of the biggest referral centers for MDS patients in Amman, Jordan. There were 112 MDS and MDS/MPN patients recorded. The male to female ratio was 1.196. The median age at diagnosis was 59 years for the whole group. The role of EASIX, NLR, and PLR as prognostic markers. The data of 112 MDS and MDS-MPN patients were included in this study, of those 13 have transformed to AML. The median age of our sample was 59 years and the male-to-female ratio was 1.196. The X-tile bioinformatics tool was used to determine the optimal cut-off point for the EASIX score, PLR, and NLR. Multivariable cox regression showed that EASIX scores exceeding 1.72 were associated with unfavorable prognosis (p < 0.001). Fisher's exact test showed that patients with EASIX scores higher than 1.72 were more likely to have 'high' and 'very high' IPSS-R risk groups (p = 0.038). Another Fisher's exact test revealed that there is an association between higher EASIX scores and AML transformation (p = 0.015). Finally, NLR and PLR showed no prognostic value in MDS. In conclusion, EASIX was found to be an independent predictor of survival in patients with MDS, unlike NLR and PLR. With that being said, EASIX scores should be utilized to help accurately estimate the prognosis of MDS patients early in the course of the disease. These findings need to be further explored and investigated in future studies with a larger number of patients.

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.

Patient Preferences for Benefits, Risks, and Administration Route of Hypomethylating Agents in Myelodysplastic Syndromes.

Therapy with infused or injected hypomethylating agents (HMAs) may lead to higher treatment administration burden (ie, local reaction, visit frequency and duration) vs. oral HMAs. OBJECTIVES: To reveal preferences of US and Canadian patients with myelodysplastic syndromes (MDS) for HMAs' benefits, risks, and administration burden through an online discrete-choice experiment (DCE). Choice of DCE attributes and survey development were informed by literature review and interviews with clinicians, MDS patients, and caregivers serving as patient proxies, and patient advocacy groups (PAGs) representatives, including from AAMAC, AAMDS, and MDSF. DCE choice tasks were analyzed using random parameter logit models. Survey patients were recruited by the PAGs via their networks. To understand key preference drivers and how much patients were willing to trade between attributes, we calculated each attribute's relative attribute importance (RAI) and marginal rates of substitution. One hundred eighty-four respondents (including 158 patients; mean age, 67.2 years; male, 50.5%; White, 50.5%; US residents, 88%) completed the survey. MDS risk was low (34.8%), high (30.9%), or unknown (34.2%). RAI (in decreasing order) was as follows: risk of AML (40%), fatigue level (33%), number of visits (12%), mode of administration (6%), visit duration (5%), and administration frequency (4%). Assuming the same risk of AML transformation or level of fatigue, most respondents (76.6%) were predicted to switch to an oral pill if it were available to them. Given equivalent effectiveness across HMAs, patients' preferences for HMA administration method should be considered in treatment decision-making to minimize burden and facilitate adherence.

P735: THE ROLE OF SF3B1 MUTATIONS IN MYELODYSPLASTIC SYNDROMES

Background:SF3B1 is one of the most commonly mutated genes in patients with myelodyplastic syndromes (MDS), associated with ring sideroblasts (RS) and an indolent disease course. Malcovati et al. proposed MDS with mutated SF3B1 fulfilling certain criteria as distinct MDS entity (Malcovati et al., Blood, 2020). Aims: Study the SF3B1 mutation in MDS with respect to the genomic landscape, AML transformation rate and clinical outcome. Methods: We analyzed 734 patients diagnosed with MDS based on cytomorphology, cytogenetics and molecular genetics and classified according to WHO classification 2017. Amplification-free WGS was performed with a median coverage of 103x (Illumina, San Diego, CA). Reads were aligned to the human reference genome (GRCh37, Ensembl annotation, Isaac aligner) and variants were called using Strelka Somatic Variant Caller v2.4.7. Results:SF3B1 mutations were identified in 231 of 734 (31%) MDS patients and were mainly found in MDS-RS (171/200; 86%; MDS-RS-SLD: 43/51, 84%; MDS-RS-MLD: 128/149; 86%). In addition, 13% (37/300) of MDS with excess blasts (MDS-EB1/2) and 20% of MDS with isolated del(5q) harbored SF3B1 mutations. In the total cohort SF3B1 mutations were associated with better outcome (median OS: 79 vs. 53 month; p<0.0001). Within the different MDS entities SF3B1 mutations were favorable in MDS-RS-SLD (median OS: 106 vs. 25 month; p=0.009), MDS-RS-MLD (median OS: 82 vs. 64 month; p=0.049) and MDS-EB-2 (median OS: 129 vs. 25 month; p=0.011), but were associated with shorter survival in MDS with isolated del(5q) (median OS: 69 vs. 79 month; p=0.044). 144/231 (62%) SF3B1 mutated samples fulfilled the criteria proposed by Malcovati et al. (SF3B1ent). These cases were associated with longer survival compared to SF3B1 mutated samples not falling into the proposed SF3B1 entity (SF3B1nent). Within SF3B1ent 47% (67/144) did not harbor any additional mutation resulting in an average of 1.8 mutations (including SF3B1) in this group. SF3B1nent patients showed on average more mutations (MDS with isolated del(5q): 1.9; MDS-EB: 2.7; MDS-RS: 3.1). The most frequent additional mutations in all SF3B1 mutated patients were TET2 (29%), DNMT3A (16%) and ASXL1 (9%). Regarding cytogenetic abnormalities, 69/231 (30%) SF3B1 mutated samples showed aberrant karyotypes (SF3B1ent: 27/144, 19%; SF3B1nent: 42/87, 48%). Of SF3B1 mutated patients 7% (15/231) progressed to AML compared to 15% (75/503) of SF3B1 wildtype patients (median follow-up: 112 months). Notably, 80% of SF3B1nent showed AML transformations in comparison to 20% of SF3B1ent (median follow-up: 122 and 112 months). Within the 15 SF3B1 mutated patients progressing to AML 47% showed additional RUNX1 and 27% DNMT3A or TET2 mutations at MDS diagnosis. In AML-transforming patients with a low SF3B1 variant allelic frequency (VAF, n=2) additional spliceosome mutations (SRSF2 or ZRSF2) were identified at the time of diagnosis. Two other SF3B1 mutated patients showing disease progression to AML harbored MECOM rearrangements when MDS was diagnosed. During progression one patient gained a MECOM rearrangement and two patients other chromosomal aberrations present in the AML state. Image:Summary/Conclusion:SF3B1 mutations occur in several MDS entities, are associated with good clinical outcome and mainly co-occurred with TET2 mutations. Patients showed a better prognosis (longer OS, lower AML transformation rate) when categorized into the proposed SF3B1 entity. AML transformation of SF3B1 mutated MDS patients is determined by the entire genomic landscape indicating RUNX1 as potential driver.

PB2051: PRIMARY MYELOFIBROSIS IN YOUNG PATIENTS ≤50 YEARS: CLINICOPATHOLOGICAL CHARACTERISTICS, GENETIC LANDSCAPE AND DISEASE OUTCOME. A SINGLE CENTER EXPERIENCE

Background: Primary Myelofibrosis (PMF) is a rare myeloproliferative neoplasm, often diagnosed in the 6th and 7th decade. Approximately 5 and 17% of the patients are diagnosed before the age of 40 and 50 years, respectively. Aims: Here, we aim to analyze PMF patients by age group, comparing young patients (≤50 years) to older age group, in terms of clinical, pathologic, genetic profile, treatment history and outcomes. Methods: This is a single center retrospective study carried out in National Center for Cancer Care and Research, Hamad Medical Corporation over the period 2008-2021. We identified WHO-defined PMF patients and collected their demographic data, bone marrow findings, driver mutations, clinical and hematologic characteristics. DIPSS-Plus score was calculated as well. Time to progression, was considered as the time to acquisition of ≥1 of the following: Hemoglobin < 10 g/dl, Leukocyte count >25 x109/L, Platelet count < 100 x109/L, Circulating blast cells ≥1%, transfusion dependency. Overall survival (OS) and progression free survival (PFS) were assessed using Kaplan-Meier method. Results: A total of 61 patients identified, from which 33(54.1%) were ≤50 years at the time of diagnosis. The median age at diagnosis was 39 years (range 24-50). 51.5% had prefibrotic MF. Females accounted for 51.5%. DIPPS-Plus at diagnosis was calculated, 12 patients (36.4%) were low, 11(33.3%) intermediate-1, 8(24.2%) intermediate-2, and 2(6.1%) high-risk. Driver mutations; JAK2 mutation was detected in 19/33(57.6%), CALR in 10/26 (38.5%), MPL in 1/6 (16.7%) and only 1 was triple-negative. 30 patients had cytogenetic information. 29/30(96.7%) showed favorable Karyotype (of which 27 had normal Karyotype). Around half of patients showed disease progression and two third (23 patients) need treatment eventually mainly Cytoreduction 18/23 (78.3%) then Ruxolitinib 11/23 (47.8%), 1 underwent Bone marrow transplant (BMT). Complications include thrombosis in 21.2% and refractory anemia 33.3% with transfusion need in 21.2%, but no leukemic transformation. 28 patients (84.8%) were alive over follow up period. Comparison between 2 studied groups were summarized in Table 1. Three patients died in the age group >50 years and one patient died in age group ≤50 years. No statistically significant difference observed in median OS between age ≤50 years (median 276.9 months, 75th percentile 276.8 months) and > 50 years (median 315.9 months, 75th percentile 108.7 months) (Log rank test P-value 0.494). The median PFS was observed to be higher in patients with age ≤50 years (median PFS 249.8 months, 75th percentile 249.8 months) compared to patients with age >50 years (median PFS 105.3 months, 75th percentile 93.04 months), however this observed difference was statistically insignificant (Log rank test P-value 0.172). Image:Summary/Conclusion: PMF is rarely diagnosed in patients ≤ 50 years old (estimated < 20%), but surprisingly it constitutes > 50% of our cohort. Young patients showed female predominance, more favorable cytogenetics, lower risk-score categories, better disease outcome and no AML transformation. Interestingly, the young group displayed higher median Lactate dehydrogenase level which is marker of cell turnover, and corelated as well with higher median leucocyte and peripheral blast count, along with more frequent splenomegaly and constitutional symptoms indicating prominent clonal myeloproliferation. No difference between the two groups regarding the degree of anemia, platelets counts and disease complications. The prognosis in these patients seems more favorable with higher median PFS over the observed period of follow up.

P733: DHX9 HELICASE DYSFUNCTION CONTRIBUTES TO DISEASE PROGRESSION IN PATIENTS WITH MYELODYSPLASTIC SYNDROMES

Background:DHX9 is a member of the DEAH (Asp-Glu-Ala-His) helicase family, and participates in regulating DNA replication and RNA processing. DHX9 dysfunction promotes tumorigenesis in several solid cancers. However, the role of DHX9 in myelodysplastic syndromes (MDS) is still unknown. Aims: to investigate the role of DHX9 in the pathogenesis of myelodysplastic syndromes. Methods:DHX9 expression was analyzed in 120 MDS patients and 42 non-MDS benign controls by quantitative PCR. Clinical significance of changes in DHX9 expression was investigated in disease progression and survival. Lentivirus-mediated DHX9 knockdown experiments were performed to investigate its biological function. The mechanistic involvement of DHX9 in MDS development was explored in cell functional assays, gene microarray and pharmacological intervention. Considering the importance of DHX9 in regulation of R-loop, we also investigated the role of DHX9 and R-loop in MDS. Results: We found that overexpression of DHX9 is frequent in MDS patients, and associated with poor survival and high risk of AML transformation. Cell functional assays showed that DHX9 is essential for the maintenance of malignant proliferation of leukemia cells, and knockdown of DHX9 results in increased cell apoptosis and growth inhibition. Gene expression profile and bioinformatics analysis reveal that DHX9 may be involved in PI3K-AKT signaling pathways. Validating experiments show that DHX9 is indispensable for the activation of PI3K-AKT signaling as knockdown of DHX9 inactivates the PI3K-AKT signaling, reduces the expression of anti-apoptosis genes such as CCND2, MYC and BCL2. In addition, we found that DHX9 knockdown leads to R-loop accumulation in MDS cells, and induces R-Loop-dependent DNA damage through ATR-Chk1 activation. It suggests that overexpressed DHX9 could counteract cell growth defect caused by R-Loop which is quite common in MDS patients especially in those with splicing genes mutations. Summary/Conclusion: Our data suggest that DHX9 contributes to disease progression by activation of PI3K-AKT signaling and correcting R-loop-mediated growth defect in MDS, and may serve as a novel prognostic marker for AML transformation and therapeutic target in MDS.

S193: GENOMIC AND FUNCTIONAL IMPACT OF TP53 INACTIVATION IN JAK2V617F MYELOPROLIFERATIVE NEOPLASMS: A TRANSGENIC MOUSE MODEL APPROACH.

Background: MPN are characterized by increased proliferation of myeloid cells and a risk of transformation to AML. MPN are due to the acquisition of mutations (JAK2, CALR, MPL) leading to JAK2 pathway activation but cooperating mutations involved in MPN evolution have been described. Mutations of TP53 in JAK2V617F patients are linked to AML transformation, illustrated by development of leukemias after retroviral overexpression of JAK2V617F in TP53 inactivated (KO) cells transplanted in irradiated animals, thus a possible cooperation between TP53 inactivation and JAK2 signaling in transformation process has been postulated. However, JAK2V617F signaling has also been reported as able to reduce p53 expression per sesuggesting a redundant role of p53 inactivation in JAK2V617F cells. Aims: Determine the role of TP53 in JAK2V617F induced genetic and phenotypic modifications. Methods: To better understand the role of TP53 in MPN phenotype and evolution in steady state hematopoiesis, we developed a transgenic model of vav-cre induced JAK2V617F expression in TP53 knock-out (KO) animals and analyzed phenotype, survival, genetic modifications using stem cell compartments RNA-Seq and response to therapy of this triple transgenic mice. Results: JAK2V617F vav-inductible-Tg/TP53 KO mice were generated to recombine JAK2V617F at an endogenous level in TP53 inactivated hematopoietic cells. During follow-up, JAK2V617F/TP53KO mice developed the same phenotype than JAK2V617F transgenic mice without leukemia. In competitive repopulations with grafts with different ratio of JAK2V617F, JAK2V617F/TP53KO and wild type cells, we observed that JAK2V617F/TP53KO cells outcompete JAK2V617F cells. In order to better define TP53-dependent and independent pathways linked to these phenotypes, LT-HSC, ST-HSC, MPP, CMP, MEP and GMP from normal, JAK2V617F and JAK2V617F/TP53 KO mice were cell sorted and RNA-Seq analysis was performed. Principal component analysis demonstrated that JAK2V617F/TP53KO cells were closer to normal cells than JAK2V617F cells whatever the (stem) cell compartment, illustrating that JAK2V617F-induced modifications are largely p53 dependent. Further analysis demonstrated that approximatively half of JAK2V617F deregulated genes in the different compartments are TP53 dependent including the IFN pathways. In order to validate this finding, mice repopulated with a mix of WT and JAK2V617F (either p53 KO or wild-type) cells were treated for 8 weeks with recombinant murine pegylated IFN-a. JAK2V617F reconstituted animals entered in complete hematological remission while JAK2VF/TP53KO reconstituted animals did not, illustrating that loss of TP53 in this context induced resistance to IFN-a. On the other hand, since MPN develop in the same way in JAK2V617F-only and in JAK2V617F/TP53KO mouse, this suggests that JAK2V617F-specific pathways also found differentially expressed in JAK2V617F/TP53KO are linked to the MPN phenotype. KEGG and GO analysis demonstrated that these genes were mainly implicated in cytokine response, cell proliferation, differentiation, and leukemia evolution illustrating that the development of MPN and its possible risk of transformation in this mouse model is largely TP53 independent. Summary/Conclusion: Taken together, our results show that a large part of genetic modifications induced by JAK2V617F mutation are p53 dependent but MPN phenotype is not, TP53 loss is insufficient to induce quick leukemic transformation in steady-state hematopoiesis in Jak2 V617F MPN despite it increases LT-HSC cell proliferation and finally that TP53 loss could be involved in IFN resistance in MPN.

PB2052: CLINICOPATHOLOGIC VARIABLES AFFECTING DISEASE OUTCOME IN PRIMARY MYELOFIBROSIS. A SINGLE CENTER EXPERIENCE.

Background: Primary myelofibrosis (PMF) is a clonal myeloproliferative neoplasm. The prognosis of PMF is variable and clearly worsens with evolution of specific factors which accelerate disease progression. This is a single center retrospective study carried out in National Center for Cancer Care and Research, Hamad Medical Corporation over the period 2008-2021. In this study, we included all patients given a diagnosis of World Health Organization-defined PMF (prefibrotic and overt fibrotic). We collected demographic data, pathologic bone marrow, driver mutations, clinical and hematologic characteristics of the study patients and correlated with disease progression. Dynamic International Prognostic Scoring System – Plus (DIPSS Plus) was used as well but was further grouped into two (low and high risk groups) instead of four groups. Aims: Here we aim to study different clinicopathologic and genetic parameters that affect the disease course in PMF patients along with their treatment history and disease outcome, in order to find out the most significant factor/s. Methods: Our Cohort included 61 patients diagnosed with PMF. Variables studied were diagnosis (prefibrotic and overt fibrotic), age, anemia, DIPSS scoring as modified into 2 groups (low/ intermediate-1 vs intermediate-2/high), cytogenetic (favorable and unfavorable karyotype), JAK2V617F mutation, need to treatment, complications mainly thromboembolic complications. Time to progression, was considered as the time to progression, was defined as the time to acquisition of ≥1 of the following: Hemoglobin < 10 g/dl, Leukocyte count >25 x109/L, Platelet count < 100 x109/L, Circulating blast cells ≥1%, transfusion dependency. Overall survival (OS) and progression free survival (PFS) were assessed using time-dependent, competitive risk analysis. Kaplan-Meier method was used for survival analysis. Results were considered statistically significant when P values were less than 0.05 Results: The most significant factors adversely affected overall survival are refractory anemia (p. value 0.006), fibrotic stage of the disease (p. 0.030), higher risk group according to DIPSS scoring system (p.0.03), unfavorable karyotype (p.0.02) and eventually AML transformation (P.0.00). For factors that had a significant impact on disease progression, again included refractory anemia (p.0.000), patients with higher DIPSS score (p.0.00), patient with PMF secondary to other myeloproliferative neoplasms had worse disease outcome compared to primary PMF (p.0.026), patients who needed treatment had shown disease progression compared to those who did not need treatment (p. value 0.001). Disease progression was also significantly associated with patients who received Ruxolitinib compared to those who did not (p.value 0.000), and patients who needed cytoreduction therapy (p. 0.029) Regarding DIPPS-Plus, 39(63.9%) patients were encountered in low to Intermediate-1, while 22(36.1%) in Intermediate-2 to high risk groups. For disease stage, 32 (52.4%) were prefibrotic, but 29(47.5%) were fibrotic. 44(72.1%) patients needed treatment, while 17(27.86%) did not. On the other hand, disease progression and the overall survival were not affected by age, molecular genetics findings, hematologic counts, driver mutations or thromboembolic complications. Image:Summary/Conclusion: Among all factors studied we found that refractory anemia, unfavourable karyotype and higher risk group according to DIPSS scoring are the most important factors affecting the disease progression and overall survival with statistically significant difference.

P755: HYPERFERRITINEMIA IS A PREDICTIVE BIOMARKER OF POOR CLINICAL OUTCOMES IN CMML

Background: CMML is a heterogenous disease exhibiting features innate to MPN and MDS. Increasing evidence supports a close interplay between systemic inflammation and risk of myeloid malignancies, notably for those with history of infection or autoimmune disease. CMML has been associated with inflammation and end-organ damage related to CKD and CVD. Analysis of gene signatures from CMML-derived monocytes has shown them to be highly proinflammatory. High ferritin may serve as a practical biomarker of disease activity to help identify pts at higher risk of poor outcomes. Aims: We aimed to identify whether hyperferritinemia correlated with worse outcomes in CMML and to characterize relevant baseline clinical and molecular features associated with this clinical phenotype. Methods: Retrospective data was collected from a database of pts with CMML treated at Moffitt Cancer Center. Pts were stratified in 2 cohorts based on ferritin levels (<1000 or ≥1000 ng/mL). Hyperferritinemia was defined as ferritin >1000 as seen at diagnosis or during follow-up. Kaplan–Meier was used to estimate OS. Cox regression was used for multivariate analysis. Results: Between August 1995 and October 2020 729 pts with CMML were identified. Median age at diagnosis was 71 (17-95). Out of 571 pts with available ferritin levels 29% (n=168) developed hyperferritinemia vs 71% (n=403) who did not. mOS was 32.4 mos (95%CI 30-35 mos). Pts with higher ferritin tended to present with CMML-2 (p=0.001) and harbor a proliferative phenotype (p=0.01). They presented with higher marrow cellularity (mean 83%, p =0.08), PLT (mean 177k, p= 0.038), and lower Hb (mean 9.5, p<0.05). There was no association with % circulating IMC, monocytes, WBC or ANC at baseline. Hyperferritinemia was associated with more profound fibrosis (p=0.007), cytopenias (p<0.05), % peripheral blasts (p<0.05), RBC and PLT transfusion dependence (p<0.05). Pts with hyperferritinemia had higher risk disease per IPSS-R, CPSS and all CMML models (p<0.05); and had higher rates of AML transformation (p<0.05). Pts were also more likely to require treatment earlier (within 3 yrs of diagnosis) (p<0.05). ASXL1 (p=0.002), EZH2 (p=0.003), and SETBP1 (p=0.019) mutations were more common among pts who developed hyperferritinemia. Conversely, TET2 (p=0.001), CBL (p=0.028) and SRSF2 (p=0.003) mutations were less common. mOS for pts with hyperferritinemia was 23.9 mos (95%CI 19.9-27.9 mos), much lower than for those with ferritin <1000 (mOS 40.5 mos, 95%CI 35.4-45.5 mos) (p<0.05). In multivariate analysis, hyperferritinemia was a significant independent covariate for OS after adjusting for CPSS, transfusion dependence and disease phenotype (dysplastic vs proliferative) (HR= 0.69; 95%CI 0.53-0.89; p=0.005). Summary/Conclusion: Almost 1/3 of pts with CMML will develop hyperferritinemia. This is associated with more aggressive disease and rates of AML transformation leading to dismal outcomes. ASXL1, EZH2, and SETBP1 MTs confer a higher risk of hyperferritinemia. Our findings indicate that hyperferritinemia is an independent prognostic biomarker that may serve as a surrogate representative of disease biology and comorbidities in CMML.

Role of allogeneic transplantation in chronic myelomonocytic leukemia: an international collaborative analysis

AbstractTo determine the survival benefit of allogeneic hematopoietic cell transplantation (allo-HCT) in chronic myelomonocytic leukemias (CMML), we assembled a retrospective cohort of CMML patients 18-70 years old diagnosed between 2000 and 2014 from an international CMML dataset (n = 730) and the EBMT registry (n = 384). The prognostic impact of allo-HCT was analyzed through univariable and multivariable time-dependent models and with a multistate model, accounting for age, sex, CMML prognostic scoring system (low or intermediate-1 grouped as lower-risk, intermediate-2 or high as higher-risk) at diagnosis, and AML transformation. In univariable analysis, lower-risk CMMLs had a 5-year overall survival (OS) of 20% with allo-HCT vs 42% without allo-HCT (P < .001). In higher-risk patients, 5-year OS was 27% with allo-HCT vs 15% without allo-HCT (P = .13). With multistate models, performing allo-HCT before AML transformation reduced OS in patients with lower-risk CMML, and a survival benefit was predicted for men with higher-risk CMML. In a multivariable analysis of lower-risk patients, performing allo-HCT before transformation to AML significantly increased the risk of death within 2 years of transplantation (hazard ratio [HR], 3.19; P < .001), with no significant change in long-term survival beyond this time point (HR, 0.98; P = .92). In higher-risk patients, allo-HCT significantly increased the risk of death in the first 2 years after transplant (HR 1.46; P = .01) but not beyond (HR, 0.60; P = .09). Performing allo-HCT before AML transformation decreases life expectancy in lower-risk patients but may be considered in higher-risk patients.

Hyperferritinemia as predictive biomarker of poor clinical outcomes in CMML.

7055 Background: CMML is a heterogenous disease exhibiting features innate to MPN and MDS. Increasing evidence supports a close interplay between systemic inflammation and risk of myeloid malignancies, notably for those with history of infection or autoimmune disease. CMML has been associated with inflammation and end-organ damage related to CKD and CVD. Analysis of gene signatures from CMML-derived monocytes has shown them to be highly proinflammatory. High ferritin may serve as a practical biomarker of disease activity to help identify pts at higher risk of poor outcomes. Methods: Retrospective data was collected from a database of CMML pts treated at Moffitt Cancer Center. Pts were stratified in 2 cohorts based on ferritin levels ( &lt; 1000 or ≥1000 ng/mL). Hyperferritinemia was defined as ferritin &gt; 1000 as seen at diagnosis or during follow-up. Kaplan–Meier was used to estimate OS. Cox regression was used for multivariate analysis. Results: Between August 1995 and October 2020 729 pts with CMML were identified. Median age at diagnosis was 71 (17-95). Out of 571 pts with available ferritin levels 29% (n = 168) developed hyperferritinemia vs 71% (n = 403) who did not. mOS was 32.4 mos (95%CI 30-35 mos). Pts with higher ferritin tended to present with CMML-2 (p = 0.001) and harbor a proliferative phenotype (p = 0.01). They presented with higher marrow cellularity (mean 83%, p = 0.08), PLT (mean 177k, p = 0.038), and lower Hb (mean 9.5, p &lt; 0.05). There was no association with % circulating IMC, monocytes, WBC or ANC at baseline. Hyperferritinemia was associated with more profound fibrosis (p = 0.007), cytopenias (p &lt; 0.05), % peripheral blasts (p &lt; 0.05), RBC and PLT transfusion dependence (p &lt; 0.05). Pts with hyperferritinemia had higher risk disease per IPSS-R, CPSS and all CMML models (p &lt; 0.05); and had higher rates of AML transformation (p &lt; 0.05). Pts were also more likely to require treatment earlier (within 3 yrs of diagnosis) (p &lt; 0.05). ASXL1 (p = 0.002), EZH2 (p = 0.003), and SETBP1 (p = 0.019) mutations were more common among pts with hyperferritinemia. Conversely, TET2 (p = 0.001), CBL (p = 0.028) and SRSF2 (p = 0.003) mutations were less common. mOS for pts with hyperferritinemia was 23.9 mos (95%CI 19.9-27.9 mos), much lower than for those with ferritin &lt; 1000 (mOS 40.5 mos, 95%CI 35.4-45.5 mos) (p &lt; 0.05). In multivariate analysis, hyperferritinemia was a significant independent covariate for OS after adjusting for CPSS, transfusion dependence and disease phenotype (dysplastic vs proliferative) (HR = 0.69; 95%CI 0.53-0.89; p = 0.005). Conclusions: Almost 1/3 of pts with CMML will develop hyperferritinemia. This is associated with more aggressive disease and higher rates of AML transformation leading to dismal outcomes. ASXL1, EZH2, and SETBP1 MTs confer a higher risk of hyperferritinemia. Our findings indicate that hyperferritinemia is an independent prognostic biomarker that may serve as a surrogate representative of disease biology and comorbidities in CMML.

Association of Somatic Gene Mutations with Risk of Transformation into Acute Myeloid Leukemia in Patients with Myelodysplastic Syndrome: A Systematic Review and Meta-Analysis.

Objectives:we aim to conduct a systematic review and meta-analysis in population of adult MDS patients to elucidate the role of these genes in AML transformation risk. Materials and Methods:The protocol for this systematic review and meta-analysis was registered in the international prospective register of systematic reviews (PROSPERO) with ID number of CRD42020218581. Systematic literature search was conducted by all authors up to October 2021 on: (1) PubMed, (2) EBSCOhost, (3) Scopus, (4) JSTOR, and (5) grey literatures. Hand-searching for relevant articles was also conducted. The following keywords with their synonyms and combinations using Boolean operators were applied to all database: “myelodysplastic syndrome”, SRSF2”, “SF3B1”, “U2AF1”, “ASXL1”, “DNMT3A”, “TET2”, “IDH1”, “IDH2”, “RUNX1”, “acute myeloid leukemia progression”, and “leukemia free survival”. Outcome was measured using hazard ratio (HR). Results:We identified 14 articles to be used for this systematic review and meta-analysis. There was no statistically significant difference in AML transformation risk between U2AF1 mutant and U2AF1 wildtype MDS patients (HR: 1.41; 95% CI: 0.95–2.07, p=0.08, I2=0%). Pooled HR showed that patients with SRSF2 mutation had higher risk of AML transformation (HR 2.62; 95% CI: 1.54-4.45; p= .0004; I2= 55%). The pooled HR for SF3B1 was 0.48 (95% CI: 0.22–1.06, p=0.07, I2=55%). Mutations of TET2, ASXL1, and EZH2 were not associated with AML transformation. Meanwhile, DNMT3A mutations were associated with AML transformation with pooled HR of 2.73 (95% CI: 1.43-5.21; p= 0.08; I2: 67%). The pooled HR for IDH genes was smaller (HR: 2.92; 95%CI: 1.21-7.06; p=0.02; I2:65%). Patients with RUNX1 mutation were associated with AML transformation (HR: 1.85; 95%CI: 1.11-3.09; p=0.02; I2:38%). Conclusion:Based from our analyses, MDS patients with mutations of SRSF2, DNMT3A, IDH, and RUNX1 have higher hazard ratio for AML transformation.

DNMT3A R882 Mutations Confer Unique Clinicopathologic Features in MDS Including a High Risk of AML Transformation

DNMT3A mutations play a prominent role in clonal hematopoiesis and myeloid neoplasms with arginine (R)882 as a hotspot, however the clinical implications of R882 vs. non-R882 mutations in myeloid neoplasms like myelodysplastic syndrome (MDS) is unclear. By data mining with publicly accessible cancer genomics databases and a clinical genomic database from a tertiary medical institution, DNMT3A R882 mutations were found to be enriched in AML (53% of all DNMT3A mutations) but decreased in frequency in clonal hematopoiesis of indeterminate potential (CHIP) (10.6%) or other myeloid neoplasms including MDS (27%) (p<.001). Next with the largest cohort of patients with DNMT3A R882 mutant MDS known to date from multiple institutions, DNMT3A R882 mutant MDS cases were shown to have more severe leukopenia, enriched SRSF2 and IDH2 mutations, increased cases with excess blasts (47% vs 22.5%, p=.004), markedly increased risk of AML transformation (25.8%, vs. 1.7%, p=.0001) and a worse progression-free survival (PFS) (median 20.3, vs. >50 months, p=.009) than non-R882 mutant MDS cases. DNMT3A R882 mutation is an independent risk factor for worse PFS, and importantly the differences in the risk of AML transformation between R882 vs. non-R882 mutant patients cannot be explained by different treatment approaches. Interestingly the higher risk of AML transformation and the worse PFS in DNMT3A R882 mutant MDS cases are mitigated by coexisting SF3B1 or SRSF2 mutations. The unique clinicopathologic features of DNMT3A R882 mutant MDS shed light on the prognostic and therapeutic implications of DNMT3A R882 mutations.

Risk of mortality and second malignancies in primary myelofibrosis before and after ruxolitinib approval

BackgroundPrimary myelofibrosis (PMF) is associated with morbidity and mortality. Ruxolitinib gained US FDA approval for treatment of intermediate/high-risk PMF in November 2011. We evaluated differences in survival and second primary malignancy (SPM) incidence among US PMF patients in the years before and after ruxolitinib approval. MethodsWe conducted a retrospective study utilizing the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER)-18 database for PMF patients. We divided patients into five-year cohorts pre- (2007−2011) and post-ruxolitinib (2012−2016) approval and compared relative survival rates (RSRs) to the standard population and standardized incidence rates (SIRs) of SPMs between cohorts. ResultsWe included 2020 patients diagnosed with PMF from 2007−2016 in this study. There was no difference in the four-year RSRs between cohorts (54 % vs. 57 %, p = 0.776). More patients developed SPMs in the post-ruxolitinib cohort (8% vs. 6%, p = 0.041). The majority of SPMs were hematologic with higher incidence of AML transformation in the post-ruxolitinib cohort (SIR 125.29 vs. 70.55). ConclusionsPMF prognosis remains poor in the years following ruxolitinib’s approval. SPM incidence including AML transformation is higher in the years after approval. Further studies are needed to determine the true impact of ruxolitnib on population outcomes.

Health-Related Quality of Life in a Biologic Assignment Trial of Reduced Intensity Hematopoietic Cell Transplantation Based on Donor Availability in Patients Aged 50-75 with Advanced Myelodysplastic Syndrome

Health-Related Quality of Life in a Biologic Assignment Trial of Reduced Intensity Hematopoietic Cell Transplantation Based on Donor Availability in Patients Aged 50-75 with Advanced Myelodysplastic Syndrome

Clinical Characteristics and Outcome of Patients with EZH2- Mutant Myelodysplastic Syndromes

Clinical Characteristics and Outcome of Patients with EZH2- Mutant Myelodysplastic Syndromes

Clinical and Pathological Characteristics of Hypocellular Myelodysplastic Syndrome : A Single-Center Retrospective Study

Background : Hypocellular myelodysplastic syndrome(MDS) is a distinct subset of MDS. It is defined as cellularity less than 30% in patients' age ≤70, or less than 20% in patients' age>70. More studies suggest that hypocellular MDS has distinct biology and clinical characteristics. Here we investigated clinical, pathological characteristics of patients with hypocellular MDS and their outcome.Methods : Patients with newly diagnosed MDS from January 2010 to June 2021 at the University of Texas MD Anderson Cancer Center were retrospectively reviewed. Patient and disease characteristics were collected to compare between hypocellular MDS and normo-/hypercellular MDS groups. Further detailed analysis focusing on patients who were investigated 28-gene or 81-gene mutation panels were conducted including de novo MDS and therapy-related MDS(t-MDS). Survival data for detailed analysis was updated in July 2021, and multivariate analyses were conducted with step-wise selection(p-value cutoff 0.10). IPSS-R was used to confirm risk stratification in hypocellular MDS patients.Results : Out of 1,789 newly diagnosed MDS patients, 179 patients were identified as hypocellular MDS. Hypocellular MDS patients present with lower CBC counts(p<.0001). More t-MDS were identified in hypocellular MDS group (n=83, 46%) compared to normo/hypercellular MDS group (n=513, 32%), (p< .001). Other baseline characteristics were comparable between hypocellular MDS patients and normo/hypercellular MDS patients (Table 1). There was no difference in overall survival (OS)(median 25.3 months vs 22.5 months, respectively, Figure 1a) or transformation-free survival(TFS)(Figure 1b) between hypocellular MDS group and normo/hypercellular MDS group (HR in OS for hypocellular MDS patients : 1.05, 95% CI 0.86-1.29, p=.645). Hypocellularity did not affect survival outcome in t-MDS (p=.420) or de novo MDS (p=.745).A total number of 153 hypocellular MDS patients were available for 28- or 81-gene panels. 78 patients (51%) had t-MDS. They presented with lower Hb (p= 0.045) and platelets (p=.016) than de novo MDS patients at diagnosis. Treatment history was similar; 54% of t-MDS patients were treated with HMA compared to 56% patients of de novo MDS with HMA treatment(p=.870). t-MDS patients had frequent TP53 (33% vs 15%, p=.008) and RUNX1 mutation(10% vs 0%, p=.007)(Figure 2). AML transformation rates of t-MDS(29%) were similar to that of de novo MDS (20%, p=.313). t-MDS has shorter median survival at 24.8 months compared with de novo MDS at 60.1 months (p= .018) (HR 1.75 in OS for t-MDS, 95% CI 1.09-2.81, p=.020). 17 patients were diploid without mutation, which includes 5% of t-MDS patients and 17% of de novo MDS patients. Median survival was longer at 60.1 months in those patients without significance(p=.479). Multivariate models for OS selected t-MDS, TP53, TET2 and Age 70. IPSS-R risk group of very low and low, intermediate and high were not well separated(Figure 3a), especially in t-MDS patients(Figure 3b). However, simplified mode of IPSS-R into very low, low vs. intermediate, high vs. very high has good prediction of survival including t-MDS and de novo MDS(Figure 3c). Patients with TP53 mutation had worse survival and TET2 mutation had better survival distinctively, compared to patients without those mutations(Figure 3d).Conclusion : Hypocellular MDS patients did not have survival difference compared to rest of MDS patients. These patients present with lower blood counts, and more frequently having t-MDS. t-MDS patients with hypocellularity tend to have high risk mutations of TP53 and RUNX1. IPSS-R does not stratify well to either hypocellular or t-MDS with hypocellularity patients. Risk stratification model with integration of molecular characteristics will be a study of interest. [Display omitted] DisclosuresKadia: Astellas: Other; AstraZeneca: Other; Genfleet: Other; Ascentage: Other; Cellonkos: Other; Sanofi-Aventis: Consultancy; Pulmotech: Other; Pfizer: Consultancy, Other; Novartis: Consultancy; Liberum: Consultancy; Jazz: Consultancy; Genentech: Consultancy, Other: Grant/research support; Dalichi Sankyo: Consultancy; Cure: Speakers Bureau; BMS: Other: Grant/research support; Amgen: Other: Grant/research support; Aglos: Consultancy; AbbVie: Consultancy, Other: Grant/research support. Jabbour: Amgen, AbbVie, Spectrum, BMS, Takeda, Pfizer, Adaptive, Genentech: Research Funding. Alvarado: FibroGen: Research Funding; Sun Pharma: Consultancy, Research Funding; Jazz Pharmaceuticals: Research Funding; MEI Pharma: Research Funding; CytomX Therapeutics: Consultancy; BerGenBio: Research Funding; Astex Pharmaceuticals: Research Funding; Daiichi-Sankyo: Research Funding. Sasaki: Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Research Funding. Kantarjian: Novartis: Honoraria, Research Funding; Ipsen Pharmaceuticals: Honoraria; Aptitude Health: Honoraria; Pfizer: Honoraria, Research Funding; Ascentage: Research Funding; Immunogen: Research Funding; Jazz: Research Funding; Astellas Health: Honoraria; KAHR Medical Ltd: Honoraria; Amgen: Honoraria, Research Funding; BMS: Research Funding; AbbVie: Honoraria, Research Funding; Precision Biosciences: Honoraria; Astra Zeneca: Honoraria; NOVA Research: Honoraria; Taiho Pharmaceutical Canada: Honoraria; Daiichi-Sankyo: Research Funding.

Assessing the Role of Venetoclax in Combination with Hypomethylating Agents in Higher Risk Myelodysplastic Syndromes

Assessing the Role of Venetoclax in Combination with Hypomethylating Agents in Higher Risk Myelodysplastic Syndromes