Azacitidine Therapy Research Articles

Low Plasma Citrate Levels and Specific Transcriptional Signatures Associated with Quiescence of CD34+ Progenitors Predict Azacitidine Therapy Failure in MDS/AML Patients.

Simple SummaryEpigenetic drugs, such as azacitidine (AZA), hold promise in the treatment of myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML), however, the mechanisms predicting the patients’ response to AZA is not completely understood. Quiescence of hematopoietic CD34+ progenitors has been proposed as a predictive factor for AZA therapy failure in MDS/AML patients, but the interplay between CD34+ cell cycle status and their metabolic signature in a predisposition to AZA (non)responsiveness remains unclear. Our data on patients with MDS or AML with myelodysplasia-related changes (AML-MRC) suggest that AZA-responders have actively cycling CD34+ cells poised for erythro-myeloid differentiation, with high metabolic activity controlling histone acetylation. Conversely, the patients who progressed early on AZA therapy revealed quiescence signature of their CD34+ cells, with signs of reduced metabolically-controlled acetylation of histones needed for transcription-permissive chromatin configuration. Our study delineates plasma citrate levels and CD34+ cells’ transcriptional signatures associated with cycling status and metabolic characteristics as factors predicting the response to AZA monotherapy in MDS/AML-MRC patients.To better understand the molecular basis of resistance to azacitidine (AZA) therapy in myelodysplastic syndromes (MDS) and acute myeloid leukemia with myelodysplasia-related changes (AML-MRC), we performed RNA sequencing on pre-treatment CD34+ hematopoietic stem/progenitor cells (HSPCs) isolated from 25 MDS/AML-MRC patients of the discovery cohort (10 AZA responders (RD), six stable disease, nine progressive disease (PD) during AZA therapy) and from eight controls. Eleven MDS/AML-MRC samples were also available for analysis of selected metabolites, along with 17 additional samples from an independent validation cohort. Except for two patients, the others did not carry isocitrate dehydrogenase (IDH)1/2 mutations. Transcriptional landscapes of the patients’ HSPCs were comparable to those published previously, including decreased signatures of active cell cycling and DNA damage response in PD compared to RD and controls. In addition, PD-derived HSPCs revealed repressed markers of the tricarboxylic acid cycle, with IDH2 among the top 50 downregulated genes in PD compared to RD. Decreased citrate plasma levels, downregulated expression of the (ATP)-citrate lyase and other transcriptional/metabolic networks indicate metabolism-driven histone modifications in PD HSPCs. Observed histone deacetylation is consistent with transcription-nonpermissive chromatin configuration and quiescence of PD HSPCs. This study highlights the complexity of the molecular network underlying response/resistance to hypomethylating agents.

Modulation of IL-6/STAT3 signaling axis in CD4+FOXP3- T cells represents a potential antitumor mechanism of azacitidine.

CD4+ T cells orchestrate immune responses and are actively engaged in shaping tumor immunity. Signal transducer and activator of transcription (STAT) signaling controls the epigenetic tuning of CD4+ T-cell differentiation and polarization, and perturbed STAT signaling networks in CD4+ T cells subvert antitumor immunity in malignancies. Azacitidine (AZA), the mainstay therapy for high-risk myelodysplastic syndromes (HR-MDS), affects CD4+ T-cell polarization and function, but whether this contributes to AZA efficacy is currently unknown. By using functional proteomic, transcriptomic, and mutational analyses in 73 HR-MDS patients undergoing AZA therapy, we demonstrate that responding patients exhibited a coordinated CD4+ T-cell immune response and downregulated the inflammatory cytokine signaling pathways in CD4+ T cells after AZA, in contrast to nonresponders who upregulated the same pathways. We further observed an AZA-mediated downregulation of intereukin-6 (IL-6)-induced STAT3 phosphorylation in CD4+FOXP3- conventional T cells (Tcons) that correlated independently with better response and survival, whereas it was also not associated with the mutation number and profile of the patients. The AZA-induced downregulation of IL-6/STAT3 axis in Tcons restored the STAT signaling architecture in CD4+ T-cell subsets, whereas STAT signaling networks remained disorganized in patients who upregulated IL-6/STAT3 activity in Tcons. Given the pivotal role of CD4+ T cells in adaptive immunity, our findings suggest that the downregulation of the IL-6/STAT3 pathway in Tcons potentially constitutes a previously unrecognized immune-mediated mechanism of action of AZA and sets the scene for developing rational strategies of AZA combinations with IL-6/STAT3 axis inhibitors.

Efficacy, Safety, and Tolerance of Gemtuzumab Ozogamicin Combined with FLAG/FLAG-Ida or Azacitidine in Relapsed/Refractory Acute Myeloblastic Leukemia

Aim. To assess the efficacy, safety, and tolerance of gemtuzumab ozogamicin (GO) combined with FLAG/FLAG-Ida chemotherapy or azacitidine in patients with relapsed/refractory acute myeloblastic leukemia (AML) in clinical practice. Materials & Methods. The study included 32 patients (16 men and 16 women). The median age was 44 years (range 23-83 years). Among them there were 15 (46.8 %) patients with refractory and 17 (53.2 %) patients with relapsed AML. GO combined with FLAG/FLAG-Ida was administered to 15 (46.8 %) patients, whereas 17 (53.2 %) patients were treated with GO and azacitidine combination. Therapy safety was assessed according to CTCAE v. 5.0. Results. Overall response rate including complete remission (CR), CR MRD-, CR with incomplete hematologic recovery, and morphologic leukemia-free status was 59.4 % (19/32). Refractoriness was observed in 31.25 % (10/32) of patients. Early mortality was 9.4 % (3/32). Overall response was 64.7 % (11/17) in the azacitidine and 53.3 % (8/15) in the FLAG/FLAG-Ida groups. In 4 (80 %) out of 5 patients with prior to FLAG treatment refractoriness, the response was achieved after GO + azacitidine therapy. In 58.9 % (10/17) of patients who received GO + azacitidine therapy, allogeneic hematopoietic stem cell transplantation (allo-HSCT) could be performed. The incidence of GO infusion complications in the tested groups did not significantly differ (p = 0.72) and was 46.7 % (7/15) (40 % with grade 1/2 and 6.7 % with grade 3) in the GO + FLAG/FLAG-Ida group and 35.3 % (6/17) (29.4 % with grade 1/2 and 5.9 % with grade 4) in the GO + azacitidine group. In the GO + FLAG/FLAG-Ida group 5 (33.3 %) patients experienced serious adverse events (SAE) of sepsis. In the GO + azacitidine group SAEs were reported in 6 (35.3 %) patients: 4 (66.6 %) with sepsis, 1 (16.7 %) with acute cardiovascular failure, and 1 (16.7 %) with acute respiratory failure. The median (range) duration was 23 (10-39) days for neutropenia grade 4, 24 (11-38) days for neutropenia grade 3, 21 (11-41) days for thrombocytopenia grade 4, 26 (16-45) days for thrombocytopenia grade 3, and 25 (22-45) days for thrombocytopenia grade 1/2. Thrombocytopenia duration was longer in patients with GO + FLAG/FLAG-Ida therapy, however, no significant differences were identified. No cases of veno-occlusive liver disease were reported. Median overall survival (OS) for both groups (n = 32) was 31.4 months, median disease-free survival (n = 21) was 13.3 months. In the group of patients with effective treatment, the median OS was not reached. In non-responders, it was 18 months (р = 0.0442). Conclusion. GO combined with FLAG/FLAG-Ida chemotherapy or azacitidine proved effective in relapsed/refractory AML patients. Remission did not appear to be associated with ELN risk, gender, age, CD33 expression, number of prior therapy lines, or number of relapses. GO + azacitidine combination showed efficacy, safety, and good tolerance in patients with prior high-dose chemotherapy refractoriness as well as low ECOG performance status. That allowed for the subsequent allo-HSCT administration to these patients. There was no significant difference between the groups of patients in the incidence of hematologic, non-hematologic toxicity, and time to hematologic recovery. Thrombocytopenia duration was longer in patients with GO + FLAG/FLAG-Ida therapy which is consistent with literature data. GO-based effective treatment in relapsed/refractory AML considerably improves OS: during 36 months of follow-up the median was not reached.

Allogeneic Transplant Improves AML Outcomes Compared to Maintenance Venetoclax and Azacitidine Following Response to Initial Venetoclax and Azacitidine Therapy

Venetoclax and azacitidine (ven/aza) is our institutional preference for initial treatment of non-core binding factor AML patients age ≥60. Given potential durability of response in these patients, the role of transplant (SCT) in patients who achieve response to ven/aza is uncertain. To examine the potential contribution of SCT, we identified 119 patients age ≥60 who received ven/aza as initial AML therapy at our center between 1/2015 and 1/2020. We then compared outcomes for these patients based on whether they were deemed eligible or ineligible for SCT; for those deemed eligible, we compared outcomes between patients who received SCT and those who did not due to personal preference. SCT consults were generally conducted within 2 cycles of initiation of ven/aza but were delayed in some patients achieving CR until evidence of persistent or recurrent measurable residual disease (MRD). Among the 119 patients, 61 (median age 76 (61-90)) were not SCT candidates due to age or comorbidities (n=44) or early death due to primary refractory disease/acute toxicity (n=17). 60 patients were potential SCT candidates. 21 patients median age 65 (60-73) underwent SCT. 2 of these patients had MDS prior to developing AML and underwent SCT consult before developing AML and initiating ven/aza. For the remaining 19 patients, consult occurred median of 50 days (20-287) from diagnosis. 2 patients relapsed after initiating ven/aza prior to transplant, underwent induction, and then went on to SCT. SCT occurred median 176 (69-643) days from diagnosis and median 133 (49-615) days from SCT consult. 37 patients median age 72 (64-78) had SCT consults but did not undergo SCT. 5 of these patients had refractory disease and never achieved SCT eligibility, one patient was deemed not an SCT candidate after consult due to social issues, and one patient was lost to follow up. The remaining 30 patients median age 72 (64-78) achieved adequate response for SCT but elected to defer. 2 of these 30 patients had MDS prior to developing AML and underwent SCT consult before developing AML and initiating ven/aza. Among the 28 patients who had SCT consults after initiating ven/aza and deferred SCT, SCT consult occurred median of 64 days (14-222) from diagnosis. Details of ELN risk status and disease status at time of SCT consult, time of SCT, and best disease response for non-SCT patients are provided in Table 1. MRD positivity included disease detected by cytogenetics, FISH, flow cytometry, or digital droplet PCR (ddPCR). Donor sources were cord (n=11), haplocord (n=3), and matched related donor (n=7). Conditioning regimens included 7 non-myeloablative, 12 reduced-intensity, and 2 myeloablative. Overall survival (OS) was significantly greater among SCT patients (median survival not reached) versus patients undergoing SCT consult and deferring SCT (median 588 days) (p=0.01) versus patients not considered SCT candidates due to age or comorbidities (median 291 days) (p=<0.001). OS was significantly greater for patients undergoing SCT consult and deferring SCT versus patients not considered SCT candidates due to age or comorbidities (p=0.01) (Figure 1). Among patients SCT eligible but deferring SCT, OS trended toward improved among patients with best disease response of CR or CRi without MRD (n=22 median 811 days) versus patients whose best disease response continued to include MRD (n= 8 median 443 days) (p=0.13). Favorable ELN status (n=10) was associated with improved OS compared to intermediate or unfavorable (n=20) (p=0.036, median survival 871 versus 443 days). Among SCT patients, OS was comparable whether patients went to SCT with (n=14) or without MRD (n=7) (p=0.49). ELN status did not impact OS; only 3 patients had favorable status. Median survival was not reached in any arm. For SCT eligible patients, SCT appears to improve outcomes among patients who respond to ven/aza compared to patients who defer SCT. Preliminary data suggests that outcomes may be improved for patients going to transplant with MRD following initial therapy with ven/aza as compared to traditional chemotherapy induction. Ongoing data to further refine the significance of MRD, molecular and cytogenetic prognostic factors, and optimal timing of SCT, as well as standardized tools to assess MRD, are necessary. Disclosures Pollyea: Syndax: Consultancy; Glycomimetics: Other; Syros: Consultancy; Abbvie: Consultancy, Research Funding; Karyopharm: Consultancy; Takeda: Consultancy; Daiichi Sankyo: Consultancy; Agios: Consultancy; Celgene/BMS: Consultancy; Pfizer: Consultancy; 47: Consultancy, Research Funding; Janssen: Consultancy; Amgen: Consultancy; Genentech: Consultancy; Novartis: Consultancy.

Sequential Analysis of miRNA Profiling during Azacitidine and Lenalidomide Therapy in Myelodysplastic Syndromes

Background and Rationale. Inositide signalling regulated by Phospholipase C (PLC) and AKT is involved in epigenetic processes and in MDS progression to AML. miRNAs are small non-coding RNAs that regulate gene expression by acting on the epigenetic machinery and are themselves controlled by epigenetic mechanisms. The expression of miRNAs has been definitively linked to cancer development and miRNA profiles are studied as new prognostic factors or therapeutic new perspectives (Jiang X et al. Nat Commun 2016). Azacitidine (AZA) is a standard first-line therapy in high-risk MDS. Its combination with Lenalidomide (LEN) has been tested, but its molecular effect is still under investigation, although the concurrent acquisition of specific point mutations on PI3KCD, PLCG2 and AKT3 genes has recently been associated with loss of response to this combination therapy (Follo MY et al. Leukemia 2019). Here we further analyzed the effect of AZA+LEN therapy on epigenetic processes and inositide regulation, focusing on miRNA expression in MDS patients. Patients and Methods. This study included 12 high-risk MDS patients treated with AZA (75 mg/m2/day, days 1-5, sc) and LEN (10 mg/day, days 1-21, orally) every 4 weeks. Patients showing complete remission (CR), partial remission (PR) or any hematologic improvement were considered as responders, while patients showing stable disease or disease progression were considered as non responders. miRNAs expression was assessed using an Affymetrix miRNA 4.0 array on patients' cells extracted at baseline and during the therapy, at the 4th (T4) and 8th (T8) cycle of therapy. Results. All patients included in this study were considered evaluable for response. 2 patients never responded, while 10 patients showed a positive response within T4: 9 of them maintained it at T8, whereas the remaining patient lost response at T8. These clinical results do not mirror the expected clinical outcomes, but this is due to our small population. However, our analyses could be relevant to test the molecular effect of the therapy in a time course, as well as comparing different phases (baseline vs T4; baseline vs T8; T4 vs T8). Paired analysis within the same patients during treatment course showed 61 miRNAs up- or down-regulated (p<0.01), with 23 mature miRNAs affected. Four of them (hsa-miR-3065-5p, hsa-miR-3674, hsa-miR-124-3p and hsa-miR-136-5p) specifically target inositide-specific genes, especially PLCG2 and AKT3, whose point mutation has previously been associated with loss of response to AZA+LEN therapy (Follo MY et al. Leukemia 2019). More interestingly, miR-124-3p and miR-136-5p were specifically down-regulated during therapy, hinting at a relevant role for these miRNAs on inositide regulation during AZA+LEN response. To analyze data from another point of view, miRNA profiling was also compared on patients at baseline and T4 showed alterations on 42 miRNAs, with two of them (hsa-miR-192-5p and hsa-miR-21-5p, targeting PI3K/Akt signalling) being specifically up-regulated, while comparison of baseline vs T8 showed 15 miRNAs altered, with hsa-let-7f-2-3p (targeting GSK/PI3K signalling) being down-regulated. Finally, paired analysis of T4-T8 samples showed 24 miRNAs altered, with hsa-miR-224-5p (targeting PI3K/Akt) specifically down-regulated. Conclusions. This preliminary study shows that AZA+LEN therapy affects the expression of specific clusters of miRNAs that target the PI3K signalling and, more specifically, three inositide genes that are mutated and associated with loss of response to this combination therapy, i.e. PI3KCD, AKT3 and PLCG2. Additional studies are warranted to confirm these data and to further analyze the role of these clusters, especially to test their pathogenetic or therapeutic relevance in MDS. Disclosures Cavo: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GlaxoSmithKline: Honoraria, Speakers Bureau; Karyopharm: Honoraria. Finelli:Janssen: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Post-Treatment Clone Size Predicts Survival Independently of IPSS-R and Response after Azacitidine Therapy for MDS.

Background DNA hypomethylating agents (HMAs), including azacytidine (AZA) have been established as key drugs for higher-risk myelodysplastic syndromes (MDS). We and others have explored the role of mutation profile before AZA administration on predicting outcomes. Actually, we have previously identified mutated-TP53 as a marker associated with higher rate of achieving complete remission (CR). In addition, mutations in TP53 and DDX41 predicted reduced and prolonged survival after treatment, respectively. However, the clinical significance of evaluating clone size changes early after treatment has not been determined. In this study, we explored the role of post-treatment clone size in predicting outcomes of AZA treatment for MDS and related diseases. Methods We enrolled 290 AZA-treated cases, including 88 from a Japanese prospective study (JALSG MDS-212 trial), 149 from Karolinska Institute, and 53 from a retrospectively collected Japanese cases. The diagnoses were MDS (n=242), MDS/MPN (n=25), and AML-MRC (n=23). For all patients, tumor samples were collected both before and after AZA administration and were analyzed for mutations in 66 genes implicated in myeloid neoplasms using targeted-capture sequencing. The median cycles of AZA treatment before sampling was 4 (range 1-7). Clone size was calculated from variant allele frequency adjusted for ploidy or allelic imbalances.Survival was calculated with a Cox regression model. Results In post-treatment samples, we identified 870 mutations in 51 genes in 255 (88%) patients with a median of 3 mutations per sample, while 943 mutations were seen in 279 (96%) patients in the pre-treatment samples. Most frequently detected mutations in post-treatment samples were seen in TET2, TP53, RUNX1, and ASXL1. Germline DDX41 mutations were excluded from clone size evaluation. Median clone sizes were 0.63 and 0.54 for pre-treatment and post-treatment samples (P=.011), respectively. The largest clone sizes (max(VAF)) in post-treatment samples had a strong negative correlation with hematological response according to IWG criteria (P < .0001). We next explored whether max(VAF) in post-treatment samples provides a more precise estimation of long-term survival than IPSS-R. Max(VAF) further stratified each IPSS-R risk group in subgroups with discrete OS (P < .0001 for IPSS-R very high and P = .0004 for high risk group). Incorporating pre-treatment mutation data (mutations in TP53 and DDX41) and max(VAF) values in addition to IPSS-R scores and clinical response, we constructed a multivariate model and found that all these factors had an independent and significant impact on OS (Figure 1A). Next, we examined whether max(VAF) combined with IPSS-R and clinical response can improve the model. For this purpose, we randomly split the cohort into 75% training and 25% validation subsets and for each split, we constructed different models using the training set, performance of which was evaluated by calculating the concordance index (c-index) using the validation set. The mean c-index in 10,000 simulation sets increased by 0.025 by adding response data to IPSS-R score (I versus IR in Fig 1B). Further improvements were obtained by adding gene mutation and max(VAF), in which the c-index increased by 0.034 (IR versus IGR in Fig 1B) and 0.010 (IGR versus IGRP in Fig 1B), respectively. For the 53 patients who received allogeneic stem cell transplantation, the median post-transplant OS was 82.6 months (range, 36.3 to not reached). Notably, max(VAF) significantly stratified OS after allo-SCT (HR, 3.3; 95%CI, 1.3 to 8.3; P = .014). Conclusions Our study revealed that post-treatment clone size significantly correlated with clinical response and the evaluation of post-treatment clone size allows for more precise prognostication after AZA treatment compared with IPSS-R and clinical response alone. Table Disclosures Naoe: NIPPON SHINYAKU CO.,LTD.: Speakers Bureau; Sysmex co.: Speakers Bureau; Eisai Co., Ltd.: Speakers Bureau; Astellas Pharma Inc.: Speakers Bureau; Bristol-Myers Squibb Company: Speakers Bureau. Miyazaki:Celgene: Honoraria; Sumitomo Dainippon Pharma Co., Ltd.: Honoraria; Kyowa Kirin Co., Ltd.: Honoraria; Novartis Pharma KK: Honoraria; NIPPON SHINYAKU CO.,LTD.: Honoraria; Otsuka Pharmaceutical: Honoraria; Astellas Pharma Inc.: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria. Papaemmanuil:Kyowa Hakko Kirin: Consultancy, Honoraria; Prime Oncology: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Illumina: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; MSKCC: Patents & Royalties; Isabl: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees. Ogawa:Eisai Co., Ltd.: Research Funding; Chordia Therapeutics, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; KAN Research Institute, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Asahi Genomics Co., Ltd.: Current equity holder in private company; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding.

Dynamic Change of Peripheral Blood WT1-mRNA within Three Cycles of Azacitidine Therapy Predicts Treatment Response in High-Risk Myelodysplastic Syndrome

Dynamic Change of Peripheral Blood WT1-mRNA within Three Cycles of Azacitidine Therapy Predicts Treatment Response in High-Risk Myelodysplastic Syndrome

Myelodysplastic Syndromes with 20q Deletion: Incidence, Prognostic Value and Impact on Response to Azacitidine of ASXL1 Chromosomal Deletion and Genetic Mutations

Introduction : The 20q deletion [del(20q)] is a recurrent chromosomal aberration in myelodysplastic syndromes (MDS) and, as a single abnormality, is associated according to the Revised International Prognostic Scoring System (IPSS-R) with a favorable outcome. However, the breakpoint of del(20q) is very heterogeneous and may cause deletion of the ASXL1 gene (20q11.21). This gene is an important epigenetic regulator of hematopoiesis and its mutations have been associated in MDS with a shorter overall survival (OS) and a lower response to azacitidine (AZA). Aim: To assess the incidence, prognostic value and impact on response to AZA of ASXL1 chromosomal alterations and genetic mutations in MDS patients with del(20q). Methods: We studied 153 patients diagnosed with MDS and del(20q) as a sole abnormality (n=93), with an additional chromosomal abnormality (n=27) or in a complex karyotype (n=33). Response to AZA therapy was assessed using the 2006 International Working Group (IWG) criteria. Analysis of ASXL1 chromosome alterations was performed by FISH (Empire Genomics probe). Samples with ASXL1 alterations by FISH were analyzed using the Agilent SurePrint G3 Human CGH 8x60K Microarray. Mutations of ASXL1 were detected by Sanger sequencing. SF3B1, SRSF2, U2AF1, DNMT3A, IDH1, IDH2, TP53, RUNX1, and SETBP1 mutations were screened by high-resolution melting and positives were confirmed by Sanger sequencing. An in vitro assay of the response to AZA in HAP1 and HAP1 ASXL1 knockout cell lines (Horizon) was also performed. The association of the clinical characteristics with the molecular findings was analyzed with the SPSS statistical program (v.20.0) and P values <0.05 were considered as statistically significant. Results: Main patient characteristics are shown in Table 1.ASXL1 chromosomal alterations were detected by FISH in 44 patients (29%; Fig. 1): 34 patients (22%) with gene deletion (ASXL1DEL) and 10 cases (6.5%) with additional gene copies (ASXL1GAIN). All 44 cases were analyzed by microarray, and alterations in centromeric KIF3B gene (20q11.21) were also identified in 24 patients (16%). Patients with ASXL1DEL showed a lower platelet count (median, 68x109/L vs. 103x109/L, P=0.046), a poorer response to AZA (response, 9% vs. 43%, P= 0.040) and a trend towards a lower OS (34 vs. 65 months, P=0.057). ASXL1 and KIF3B chromosomal gains were associated with complex karyotypes (ASXL1GAIN, 80% vs. 23%, P<0.001; KIF3BGAIN, 80% vs. 25%, P=0.011). Patients with ASXL1GAIN had a similar OS and response to AZA than ASXL1nonDEL/ASXL1nonMUT patients (OS, 51 vs. 73 months, P=0.86; response, 60% vs. 44%, P=0.43). Seventy patients (46%) in the series had ≥1 genetic mutation (Fig. 1). ASXL1 mutations (ASXL1MUT; 22/153, 14%) were mostly frameshift (n=17, 77%) or nonsense (n=4, 18%) and were associated with a lower hemoglobin level (median, 8.3 vs. 10.3 g/dL; P=0.007), a higher ferritin level (median, 691 vs. 286 ng/mL, P=0.014), a higher number of mutations (23% vs. 0% ≥3 mutations, P<0.001) and a lower OS (22 vs. 62 months, P=0.016). U2AF1 mutations were associated with a deeper neutropenia (median, 1.17x109/L vs. 1.83x109/L, P=0.026) and TP53 mutations were associated with acute myeloid leukemia (AML) transformation (55% vs. 16%, P=0.005) and a lower OS (24 vs. 57 months, P=0.037). In the global series, patients with ASXL1 altered either by chromosomal deletion or mutation (ASXL1DEL/ASXL1MUT) had a poorer response to AZA (13% vs. 47%, P=0.020) and a lower OS (32 vs. 70 months, P=0.005; Fig. 2) than the remaining patients. In the analysis of isolated del(20q) subgroup (n=93), ASXL1DEL/ASXL1MUT patients also showed a lower OS (37 vs. 80 months, P=0.026) and ASXL1DEL was associated with a higher risk of progression to AML (33% vs. 11%, P=0.029), despite 64% of patients were clustered in lower-risk categories of the IPSS-R. In the in vitro assay performed at 2 μM AZA, HAP1 ASXL1 knockout cells showed less growth inhibition (26% vs. 46%, P=0.003), lower cell apoptosis (17% vs. 34%, P<0.001) and less cell cycle arrest in G0/G1 phase (6% vs. 23%, P=0.009), compared to HAP1 cells. Conclusion: In MDS patients with del(20q), the alteration of ASXL1 by chromosome deletion or somatic mutation was associated with adverse clinical features and a poorer response to AZA. Its detection at diagnosis would allow the rapid identification of a subgroup of MDS patients with a poor prognosis that could benefit of earlier and more effective therapies. Disclosures Sanz: Abbvie Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; LaHoffman Roche Ltd.: Membership on an entity's Board of Directors or advisory committees; Helsinn: Membership on an entity's Board of Directors or advisory committees; Takeda Pharmaceutical Ltd.: Membership on an entity's Board of Directors or advisory committees. Tormo:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; MSD: Honoraria; Daiichi Sankyo: Honoraria; Servier: Honoraria; Roche: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees.

Estimated glomerular filtration rate independently predicts outcome of azacitidine therapy in higher-risk Myelodysplastic syndromes. Results from 536 patients of the Hellenic National Registry of Myelodysplastic and Hypoplastic syndromes.

Higher-risk Myelodysplastic syndromes (MDS) patients undergoing treatment with 5-azacytidine (AZA) are typically elderly with several comorbidities. However, the effect of comorbidities on the effectiveness and safety of AZA in real-world settings remains unclear. We analyzed data from 536 AZA-treated patients with higher-risk MDS, Myelodysplastic/Myeloproliferative neoplasms and low blast count Acute Myeloid Leukemia enrolled to the Hellenic National Registry of Myelodysplastic and Hypoplastic Syndromes. Multivariate analysis adjusted also for the International Prognostic Scoring System (IPSS), its revised version (IPSS-R) and the French Prognostic Scoring System (FPSS), demonstrated independent associations of overall and leukemia-free survival with estimated glomerular filtration rate (eGFR) <45 mL min-1 /1.73 m2 (P = .039, P = .023, respectively), ECOG performance status <2 (P = .015, P = .006), and presence of peripheral blood blasts (P = .008, P = .034), while secondary MDS also correlated with significantly shorter leukemia-free survival (P = .039). Addition of eGFR <45 mL min-1 /1.73 m2 , in IPSS-R and FPSS increased the predictive power of both models. Only FPSS ≤2 and eGFR <45 mL min-1 /1.73 m2 predicted worse response to AZA in multivariate analysis, whereas eGFR <45 mL min-1 /1.73 m2 correlated significantly with death from hemorrhage (P = .003) and cardiovascular complications (P = .006). In conclusion, in the second largest real-world series of AZA-treated MDS patients, we show that an eGFR <45 mL min-1 /1.73 m2 is an independent predictor of worse response and survival. This higher cut-off, instead of the commonly used serum creatinine >2 mg/dL, can be utilized as a more precise indicator of renal comorbidity during AZA therapy. Incorporation of eGFR in the prognostic assessment of AZA-treated MDS patients may prove useful not only in routine practice, but also for the appropriate patient stratification in clinical trials with AZA combinations.

Disappearance of Trisomy +8 In A Case with Myelodysplastic Syndrome After Azacitidine Therapy Followed by Lenalidomide Treatment

Myelodysplastic syndrome (MDS) is clonal hematopoietic stem cell disorders characterized clinically by ineffective hematopoiesis...

Acute Myeloid Leukemia (AML) Treated with Azacitidine: Survival Outcomes for Patients Who Complete More Than Six Cycles Are Similar to High-Risk Myelodysplastic Syndrome/Low Blast Count AML

INTRODUCTION: Despite accumulating evidence supporting the efficacy of hypomethylating agents in patients with AML and &gt; 30% bone marrow blasts as well as in relapsed/refractory AML, this therapy is not yet funded by National Health Plans / Healthcare Funding Agencies in a number of countries including Canada. The assistance of an industry-sponsored compassionate program has enabled provision of azacitidine for this group of patients at The Ottawa Hospital. We report here our local "real-world" experience of azacitidine efficacy in this diverse group of AML patients and identify a sub-group whose outcomes are equivalent to that of patients with higher-risk Myelodysplastic Syndrome (MDS) and AML with 20-30% blasts for whom azacitidine therapy has funding approval in Canada. METHODS: All patients who received azacitidine at The Ottawa Hospital between 2009 and 2016 were included in this single-center, retrospective analysis. Azacitidine was administered at a dose of 75mg/m2 subcutaneously daily for 7 consecutive days every 28 days. Response was evaluated with a repeat bone marrow aspirate and trephine biopsy after the 6th cycle. In those patients confirmed to have stable or responsive disease, azacitidine was continued until progression of disease, intolerable side-effects of the drug or the patient chose to discontinue therapy. Overall survival curves were generated using the Kaplan-Meier method and log-rank tests were used to compare subgroups of patients. Actuarial median survival months were calculated with 95% confidence intervals (CI). P-values less than 0.05 were considered statistically significant. RESULTS: During the study period, 109 patients received azacitidine: 54 had MDS /AML with 20-30% blasts (the 'funded' group) and 55 had either AML with &gt; 30 % blasts (n=23), AML relapsed post-intensive chemotherapy (n=14), AML relapsed post-allogeneic stem cell transplant (n=10) or primary refractory AML (n=8) (the 'unfunded' group). Median survival of the 'funded' group was 12.2 months while median survival of the 'unfunded' group was 5.6 months (95% CI 3.3-7.7; p=0.0058). Of the AML patients in the 'unfunded' group, 24% completed more than 6 cycles of azacitidine compared to 52% of patients in the 'funded' group. In both the 'funded' and 'unfunded' groups, patients who completed more than 6 cycles of azacitidine had similar survival outcomes (p=0.7277): the 'funded' group had a median survival of 19 months (95% CI 14.4-25.3) while the median survival of this sub-population of the 'unfunded' AML group was 22 months (95% CI 11.7-24.9). Patients in both groups who failed to complete more than 6 cycles of azacitidine also had a similar outcome (p=0.39), with a median survival of 5.7 months (95% CI 4.0-6.3) for patients with MDS/AML 20-30% blasts and 3.6 months (95% CI 2.2-5.1) for AML patients with &gt; 30% blasts or relapsed/refractory disease. Reasons for patients not completing at least 6 cycles of azacitidine included progression of disease (25%), bacterial infections most commonly pneumonia (53%) and patient preference (7%). CONCLUSION: A significant sub-population of AML patients with &gt; 30% blasts or refractory/relapsed AML can achieve a meaningful survival benefit with the hypomethylating agent, azacitidine. A higher proportion of this AML patient population discontinued azacitidine as a result of infective complications. The provision of routine prophylactic antibiotics may enable more patients with AML to receive an adequate amount of azacitidine to achieve therapeutic benefit and warrants further investigation. Our results add to the growing body of 'real-world' evidence that supports healthcare funding agencies to provide coverage of azacitidine for patients with AML who in some countries at present do not fulfill government funding criteria. Disclosures Bredeson: Otsuka: Research Funding. Maze:Pfizer Inc: Consultancy; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Sabloff:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; ASTX: Membership on an entity's Board of Directors or advisory committees, Research Funding; Actinium Pharmaceuticals, Inc: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas Pharma Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi Canada: Research Funding.

Updated Study Results of CX-01, an Inhibitor of CXCL12/CXCR4, and Azacitidine for the Treatment of Hypomethylating Agent Refractory AML and MDS

Hypomethylating agents (HMAs) are standard first line therapy for patients with high risk MDS and older patients with AML. Outcomes for patients who do not respond or progress on HMAs are poor, and there are no standard treatment options for these patients. The interaction between leukemic blasts and the bone marrow microenvironment is thought to play an important role in disease pathogenesis and possibly chemotherapy resistance, so we hypothesized that blocking the CXCL12/CXCR4 axis with CX-01 may improve response rates to azacitidine in patients who have failed HMA therapy. CX-01 is a low molecular weight heparin derivative with minimal anticoagulant activity that binds CXCL12 as well as neutralizes PF4, a negative regulator of megakaryopoiesis. We report updated study results of a single institution a pilot study (NCT02995655) that enrolled patients with HMA-refractory (received 4 or more cycles of HMA without response or disease progression on HMA therapy) AML or MDS (INT-1 or greater). Patients received 7 day continuous infusion of CX-01 (0.25 mg/kg/hr) and azacitidine 75 mg/m2 daily days 1-7, in 28 day cycles. The primary objective of this trial was to assess the overall response rate (ORR). 20 patients were enrolled between May 2017 and February 2018. The median age was 74 years (range 62-88 years) and 35% were female. Nine patients had MDS and 11 had AML, with 7 patients having antecedent MDS and 2 having therapy-related AML. Half of the patients had high risk cytogenetic abnormalities and 3 had TP53 mutations. Patients had a median of 2 prior lines of therapy (range 1-3) with median of 6 prior cycles of HMA therapy (range 4-20). Only 4 patients had a confirmed response to prior HMA therapy. Of the 20 patients that were enrolled, 15 were considered evaluable for response with a bone marrow biopsy after cycle 2. Of the 5 unevaluable patients, 3 were removed from the trial before completing C1 due to transaminitis, discovery of a second primary malignancy, and an elevated PTT on day 2. One patient had grade 5 sepsis during C1, and another withdrew for unrelated reasons. As expected with azacitidine therapy in this patient population, hematologic toxicity was common with 16 instances of grade 3/4 neutropenia/leukopenia, 5 instances of grade 3/4 anemia, and 10 instances of grade 3/4 thrombocytopenia. Other common grade 3/4 adverse events were various infections (20), febrile neutropenia (13), hypertension (10), electrolyte disturbance (9), and transaminitis (3). Mild prolongations in PTT (22) and INR (7) were common, and there was one instance of grade 3 PTT prolongation, two instances of grade 3 epistaxis, and one instance of grade 3 hematuria. The incidences of bleeding were not thought related to CX-01 infusion. The 15 evaluable patients received a median of 3 cycles of CX-01 and azacitidine (range 2-9). Of 15 evaluable patients, there was 1 CR and 3 bone marrow CRs (mCR, with incomplete blood count recovery), 9 stable disease, and 2 progressive disease for an ORR of 27%. Of the 3 patients with a mCR after cycle 2, two had hematologic improvement of their neutrophil and platelet counts, respectively, by the end of cycle 4. A patient with stable disease also had hematologic improvement in platelets. The median OS of evaluable patients was 221 days (95% CI 179 days-not reached) and median overall survival was not significantly different between AML patients at 221 days and MDS patients at 248 days (p = 0.8). In this pilot study we demonstrated the feasibility of treating HMA-refractory AML and MDS with CX-01 and azacitidine. While this study is limited by its small sample size, we observed higher than expected response rate and favorable OS compared to historical controls. Figure Disclosures Cashen: Celgene: Other: Speaker's Bureau; Seattle Genetics: Other: Speaker's Bureau; Novartis: Other: Speaker's Bureau. DiPersio:Incyte: Consultancy, Research Funding; WUGEN: Equity Ownership, Patents &amp; Royalties, Research Funding; Magenta Therapeutics: Equity Ownership; Amphivena Therapeutics: Consultancy, Research Funding; Celgene: Consultancy; RiverVest Venture Partners Arch Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cellworks Group, Inc.: Membership on an entity's Board of Directors or advisory committees; NeoImmune Tech: Research Funding; Macrogenics: Research Funding, Speakers Bureau; Bioline Rx: Research Funding, Speakers Bureau; Karyopharm Therapeutics: Consultancy. Jacoby:Celgene: Speakers Bureau; Novo Nordisk: Consultancy; Jazz Pharma: Membership on an entity's Board of Directors or advisory committees. Uy:Astellas: Consultancy; Pfizer: Consultancy; Curis: Consultancy; GlycoMimetics: Consultancy.

Molecular Mechanisms of Primary Resistance to Azacitidine in MDS/AML Patients - Data of the Hellenic MDS Study Group

Molecular Mechanisms of Primary Resistance to Azacitidine in MDS/AML Patients - Data of the Hellenic MDS Study Group

High Activity of Cladribine (2-CdA) Combined with Low-Dose Cytarabine in Patients with Acute Myeloid Leukemia or Myelodysplastic Syndrome after Azacitidine Failure

Background: Azacitidine (AZA) therapy is the standard of care for higher-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) patients not eligible for intensive treatment. Although nearly 50% of patients respond to AZA treatment, most of them experience disease progression within 2 years of remission. The prognosis of patients after AZA failure is dismal with a median overall survival (OS) reaching 3-6 months. Interestingly, recent studies have demonstrated clinical efficacy of cladribine combined with cytarabine in newly diagnosed AML patients. In view of epigenetic properties of cladribine and known synergy with cytarabine, it may be speculated that combination of cladribine and low-dose cytarabine (LD-AraC) exerts some clinical activity also in the setting of relapsed/refractory AML/MDS. Aim: The aim our study was to assess activity and toxicity of combination of cladribine and LD-AraC in patients with MDS/AML after AZA failure. Methods: This retrospective analysis included patients with AML with 20% to 30% blasts, high and intermediate-2 risk MDS and CMML patients with AZA failure who were treated with combination of cladribine and LD-AraC in centers of the Polish Adult Leukemia Group (PALG). Therapy started with induction phase consisting of 2 cycles of cladribine 5 mg/m2 iv on days 1-5 (cycle 1) and on days 1-3 (cycle 2) in combination with LD-AraC 40 mg/m2 sc (days 1-10). Patients who achieved remission moved on to maintenance therapy with LD-AraC 40 mg/m2 sc, days 1-10), every 4 weeks. The treatment was continued for as long as tolerated and there was a clinical benefit. Treatment response was determined in accordance with the 2017 European Leukemia Net (ELN) and the 2006 International Working Group (IWG) criteria after each cycle. Results: Overall, 16 patients (8 patients with diagnosis of AML, 7 with diagnosis of MDS, and 1 with diagnosis of CMML myelodysplastic subtype at AZA therapy initiation) who had been treated with combination of cladribine and LD-AraC at AZA failure in 3 centers of PALG between 2014 and 2019 were identified. There were 9 males and 7 females, with median age of 72 years (range 64 - 78). The patients had previously received a median of 15 cycles of AZA (range 4 - 33). At the initiation of cladribine and LD-AraC therapy the median number of blasts was 27,5% (range 15,5 - 77) with 13 patients fulfilling the criteria of AML. At the data cut-off the median of administered chemotherapy cycles reached 4 (range 1-14), with 4 patients continuing treatment. The regimen was relatively well tolerated with no treatment related deaths and the most common non-hematological adverse events of grade 3 or worse being neutropenic fever and pneumonia. Response assessment revealed that nine patients (56%) achieved a remission, including 6 complete remissions (CR) and 3 complete remissions with incomplete recovery (CRi). The median time to response was 1 cycle. Median progression-free survival was 8 months, and the median OS reached 10.6 months. The estimated 6-months and 12-months OS probability were 79.3% and 44.6%, respectively. Conclusions: The combination of cladribine and LD-AraC appears to be an attractive option in the therapy of AML/MDS patients after AZA failure. Although prospective studies are needed to confirm these findings such treatment seems to be associated with an improvement in OS compared to the historical data. Disclosures Gora Tybor: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Durable Responses and Survival in High Risk AML and MDS Patients Treated with an Allogeneic Leukemia-Derived Dendritic Cell Vaccine

Background. Maintenance of induced responses remains a significant unmet medical need in patients with acute myeloid leukemia (AML) or high risk myelodysplastic syndrome (MDS) not eligible for allogeneic hematopoietic stem cell transplantation (HSCT). The allogeneic leukemia-derived dendritic cell vaccine, DCP-001, has shown to generate both humoral and cellular immune responses and is safe for clinical practice (van de Loosdrecht et al., Cancer Immunol. Immunother. 2018). In this study we show additional data on long-term follow up and patient-related risk factors from the phase 1 study. Methods. AML- or MDS-patients (n=12), ineligible for HSCT, were included in a post-hoc clinical analysis of the DCP-001 phase I trial, receiving DCP-001 vaccination at the Amsterdam University Medical Center, VU University Medical Center, Amsterdam, the Netherlands (NCT01373515). All clinical data, including baseline characteristics as cytogenetics, pre-and post-vaccination treatment and morphologic blast counts in follow up, were retrospectively collected from corresponding patient files. Targeted next generation sequencing (NGS) gene panel data and cytogenetics were utilized to determine (cyto-)genetic risks following the European Leukemia Net (ELN) 2017 criteria. We defined 'response' as decreased or stable morphologic blast counts in bone marrow at day 126 (last day of official study evaluation) compared to study entry. Results. Seven out of twelve patients responded to treatment, the other patients showed progressive disease (data are summarized in table 1). The median relapse free survival (RFS) for the responding patients was 420 days (range 90-1849) and overall survival (OS) was 1090 days (90-2160); two patients died early in complete remission (CR) due to infection (respectively at 90 and 184 days). Notably, three of these patients were intermediate risk and four were poor risk patients based on the ELN risk classification for AML or Revised International Prognostic Scoring System (IPSS-R) for MDS. The median OS for the non-responders was 144 days (range 59-209). These five patients had relapsed or refractory disease at start of vaccination with detectable circulating peripheral blasts; four of them received additional azacitidine (AZA) therapy prior to vaccination. Moreover, they were vaccinated after induction and consolidation therapy with a median time between diagnosis and first vaccination of 611 days (219-2310) compared to 240 days (105-1398) for the seven responding patients. Of the latter, all were in complete remission (CR) (n=5) or had morphologic marrow blast counts &amp;lt;10% (n=2) at the start of vaccination. Two responders that progressed and two that relapsed after vaccination were treated with AZA, resulting in one complete remission and two partial responses (one non-evaluable due to sample failure), see figure 1. Conclusion/discussion. Clinical data of the phase 1 trial show that DCP-001 may prolong duration of remission or smoldering disease in intermediate and high risk AML or MDS patients. Response was associated with treatment by vaccination shortly after achieving CR. This should be taken into account in selection criteria of future vaccination studies. Hence, an international multi-center phase 2 study (ADVANCE II; NCT03697707) is currently being conducted to determine the effect of DCP-001 on measurable residual disease (MRD) in AML patients, aiming to convert them to a MRD negative state. Furthermore, we demonstrated that AZA can be applied as rescue therapy upon progression after vaccination. Disclosures Rovers: DCprime: Employment. Cloos:Daiicchi Sankyo: Speakers Bureau; Glycomimetics: Research Funding; Takeda: Research Funding; Novartis: Other: MRD assessments of clinical trials, Research Funding; Merus: Other: MRD assessment of a clinical trial , Research Funding; Genentech: Consultancy, Research Funding; Helsinn: Other: MRD assessment of a clinical trial; DCPrime: Other: MRD assessment of a clinical trial. de Gruijl:DCprime: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Oral Azacitidine and Cedazuridine Approximate Azacitidine Efficacy in a Murine Model

Background: DNA methyltransferase inhibitors (DNMTi) induce remissions and improve survival for patients with MDS and those with AML unable to receive standard cytotoxic chemotherapy. Accordingly, DNMTi therapy is the backbone of SOC treatment for MDS and AML. Given the inconvenience, pain, and general detriments to QOL with SQ or IV therapy daily for 5-7 days every month with azacitidine (AZA) or decitabine (DAC), many have attempted to provide the therapy orally, but encountered difficulties with this method of administration given rapid first-pass clearance via the enzyme cytidine deaminase (CDA) which is ubiquitous in the gut and liver. Recently, DAC was combined with cedazuridine (CDZ), an oral CDA inhibitor, in a fixed-dose (35mg/100mg) combination tablet (ASTX727) to approximate the pharmacokinetics of IV DAC (Savona et al Lancet Haematology 2019). To determine if a similar strategy might be feasible with AZA, we attempted to increase the bioavailability of oral AZA with CDZ in a murine tumor model. Methods: We measured GI50 in AML cell lines treated with vehicle (DMSO), AZA, and AZA/CDZ combination. Although cancer cell lines produce CDA, total levels are negligible in comparison CDA in the gut and liver. For this reason, we then studied CDZ, AZA, and the AZA/CDZ combination in a systemic model of AML in immunocompromised mice. NSGS mice were sub-lethally irradiated and administered MOLM-13 AML cells via tail vein injection. At day seven post-transplant, engrafted mice were randomized to receive 2.5 mpk i.p. AZA(n=8), 2.5 mpk oral AZA(n=8), 3 mpk CDZ + oral AZA(n=6), or CDZ alone at 30 mpk (n=7). All oral AZA and CDZ was administered via oral gavage daily for 7 consecutive days; i.p. therapy was similarly given for 7 consecutive days. During treatment, the kinetics of MOLM-13 expansion was defined by detection of human AML in the blood as detected by flow cytometry. At approximately three weeks after transplant, CDZ-only treated mice became moribund, and all experimental groups were sacrificed for analysis of chimerism. Results: After 72 hour of treatment, no differences were noted in viability of cell lines between AZA and AZA+ CDZ in vitro. In the xenograft model, as expected, i.p. AZA-treated mice had significant decreases in leukemic expansion in the bone marrow and spleen, whereas CDZ alone did not (AZA i.p. vs CDZ, p = 0.004 and &amp;lt;0.001). More importantly, whereas oral AZA alone failed to decrease AML expansion in both the bone marrow and spleen of treated mice (oral AZA vs CDZ., p = 0.677 and 0.249, respectively), the addition of CDZ to oral AZA led to significant decreases in AML in both bone marrow and spleen (Oral AZA + CDZ vs CDZ, p = 0.012 and 0.004, respectively). Likewise, addition of CDZ to oral AZA showed no significant differences in activity against AML compared to traditional AZA i.p. dosing in either bone marrow or splenic tissue (p= 0.204 and 0.224, respectively). Furthermore, in a Kaplan-Meier survival analysis, mice treated with CDZ alone die within 21 days of transplant, but both i.p. AZA and oral AZA + CDZ treated mice had a 50% extended survival with no significant difference in survival between i.p. AZA and oral AZA + CDZ treated mice (p= 0.502). H&amp;E staining revealed no significant bone marrow toxicity in treated mice, suggesting that AZA preferentially effected transplanted MOLM-13 AML cells. Conclusion: Consistent with previous preclinical and clinical studies with ASTX727, the oral AZA approximated AZA anti-tumor activity when co-treated with CDA-inhibitor CDZ. These preliminary data provide rationale for the development of CDZ + oral AZA therapy as a fixed dose combination (ASTX030) in myeloid disease. Clinical trials evaluating ASTX030 are being planned. Figure Disclosures Oganesian: Astex Pharmaceuticals, Inc.: Employment. Azab:Astex Pharmaceuticals, Inc.: Employment. Savona:TG Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sunesis: Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Patents &amp; Royalties; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Incyte Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Selvita: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Rapid improvement of secondary myelodysplastic syndrome from essential thrombocytosis (ET) treated by Azacitidine(AZA)

Abstract Background It is well known that secondary MDS is refractory to treatment. In general, high-risk MDS is treated with AZA, but its effect is often delayed. I experienced a case which has rapidly improved to the ET from secondary MDS after 2 courses of AZA. Case report A 70 - year - old woman, who had diagnosed with ET 20 years before and treated with hydroxyurea for 5 years, was admitted to our hospital with pancytopenia. On abdominal CT, it showed splenomegaly. In chromosome testing showed complex karyotypes. Plasma WT-1 level showed a significant high as 96000 copy. In bone marrow aspiration, blasts together indicate to the atypical three strains accounted for 18%, was diagnosed with secondary MDS (RAEB-t, IPSS-R: 9.5 points). Bone marrow biopsy was similar findings and myelofibrosis was not observed. She was treated with AZA at a dose of 75 mg / m2 over a 7-day subcutaneous injection, and was followed for 3 weeks. She withdrawal from transfusion-dependent in the initial treatment, and at the time of 2 the end of the course, her WBC number (990 / µl to 7240 / µl) and Hb level (6.3 g / dl to 13.8 g / dl) were normalized, and her blood platelet count was markedly increased from 56,000 / µl to 1,340,000 / µl. Plasma WT - 1 level decreased markedly from 96000 copies to 430 copies, and the splenomegaly also improved on US study. Bone marrow aspiration showed hyperplastic bone marrow accompanied by a marked increase in megakaryocytes, the three line heterozygosity disappeared, and the blasts decreased to 1.2%. Even in bone marrow biopsy consistent with ET. Discussion Secondary MDS developed with chemotherapy is generally often refractory to treatment. In our case, we withdrew from transfusion dependence with first-time AZA therapy and improved to ET, the original disease at the end of 2 courses. Secondary MDS patients who respond with small number of AZA therapy are extremely rare and are valuable cases.

Characteristics and outcomes of therapy-related myeloid neoplasms after peptide receptor radionuclide/chemoradionuclide therapy (PRRT/PRCRT) for metastatic neuroendocrine neoplasia: a single-institution series.

Peptide receptor radionuclide/chemoradionuclide therapy (PRRT/PRCRT) is an effective therapy for metastatic neuroendocrine neoplasia (NEN), but therapy-related myeloid neoplasms (t-MN) remain of concern. The study reviewed the clinicopathological features and outcomes of patients who developed t-MN. Retrospective analysis of all patients diagnosed with t-MN by 2016 WHO classification, from a cohort of 521 patients who received PRRT/PRCRT over a 12-year period. Molecular next-generation sequencing using an in-house 26-gene panel was performed. Twenty-five of 521 (4.8%) patients were diagnosed with t-MN, including six acute myeloid leukaemia (AML) and 19 myelodysplastic syndrome (MDS). The median time from first cycle PRRT/PRCRT to diagnosis of t-MN was 26months (range 4-91). Twenty-two of 25 (88%) patients had grade 1-2 pancreatic or small bowel NEN with moderate metastatic liver burden. Six patients (24%) had prior chemotherapy. Median number of PRRT cycles = 5 (22/25 (88%) with concomitant radiosensitising chemotherapy). All 25 patients achieved disease stabilisation (68%) or partial response (32%) on RECIST 1.1 at 3months post-PRRT. At t-MN diagnosis, all patients presented with thrombocytopenia (median nadir 33 × 109/L, range 3-75) and 17 (68%) remained NEN progression-free. Marrow genetic analysis revealed unfavourable karyotype in 16/25 (66%) patients with tumour protein 53 (TP53) mutation in nine (36%). Azacitidine therapy was utilised in ten eligible patients, while four received induction chemotherapy for AML. The median overall survival from first PRRT was 62months (19-94), but from t-MN diagnosis was only 13months (1-56), with death due primarily to haematological disease progression. The diagnosis of t-MN after PRRT/PRCRT is an infrequent but serious complication with poor overall survival. Most patients present with thrombocytopenia; unfavourable genetic mutations have a poor response to t-MN treatment. Prospective data are needed to explore potential pre-existing genetic factors and predictive biomarkers to minimise the risk of t-MN.

PS1455 RESPONSE TO UP‐FRONT AZACITIDINE IN JUVENILE MYELOMONOCYTIC LEUKEMIA (JMML): INTERIM ANALYSIS OF THE PROSPECTIVE EUROPEAN MULTICENTER STUDY AZA‐JMML‐001

Background:JMML is a chemotherapy‐resistant neoplasia of early childhood. Allogeneic hematopoietic stem cell transplantation (allo‐HSCT) is the only curative therapy, being able to cure approximately 50% of these children. Relapse is the major cause of treatment failure, with chemotherapy prior to HSCT being notably unsuccessful. Novel therapies controlling JMML prior to HSCT are urgently needed.Aims:We conducted a phase 2, multicenter, open‐label study to evaluate pharmacodynamics, safety, and antileukemia activity of azacitidine monotherapy prior to HSCT in patients with newly diagnosed JMML.Methods:Azacitidine was administered at 75 mg/m2/day intravenously on Days 1–7 of a 28‐day cycle for 3 to 6 cycles. The primary endpoint was the number of patients achieving clinical complete remission or clinical partial remission (cPR) at Cycle 3 Day 28 (C3D28); secondary endpoints included overall survival following HSCT.Results:Between September 2015 and November 2017, 18 JMML patients (13 PTPN11‐, 3 NRAS‐, 1 KRAS‐, 1 NF1‐mutated), aged 0.2–7.0 years, were enrolled in the study. Median (range) white blood cell (WBC) count, platelet count, and spleen size were: 19.7 (4.3–59.0) × 109/L, 28 (7–85) × 109/L, and 4 (2–14) cm below the costal margin, respectively. DNA methylation class (Lipka et al. Nat Comm. 2017;8:2126; n = 18) was high, intermediate, or low in 11, 5, and 2 patients, respectively. Sixteen patients completed 3 cycles of therapy and 5 of them completed 6 cycles. Two patients discontinued treatment before completing 3 cycles due to disease progression. Six patients (33%) experienced ≥1 grade 3 or 4 manageable adverse event, consistent with the known azacitidine safety profile. Eleven patients (61%) achieved cPR at C3D28 and 7 had progressive disease either at C3D28 or prior. Importantly, 8 of the 15 patients who needed platelet transfusions before or shortly after treatment initiation did not require transfusions at the time of HSCT. Seven of these 8 platelet responders had normalized their platelet count (≥130 × 109/L). Palpable spleen size decreased in 11 responders by a median of 3.5 cm after 3 cycles and ranged from 0 to 2 cm below the costal margin after 6 cycles. Seventeen patients received allo‐HSCT from a human leukocyte antigen‐compatible related or unrelated donor following a busulfan‐ (n = 15) or treosulfan‐based (n = 2) preparative regimen after a median of 57 days (36–112) from last azacitidine dose. Fourteen out of 16 transplanted patients were leukemia‐free at median follow‐up of 15.6 months (0.8–22.5) after HSCT. Two children (both high‐methylation class) given HSCT relapsed after the allograft. Sixteen of the 18 patients were alive at a median follow‐up of 22.2 months (14.2–33.1). One patient who discontinued treatment before Cycle 3 died from disease progression, and 1 non‐responder child died from graft failure.Summary/Conclusion:This study showed azacitidine monotherapy was well tolerated in children with newly diagnosed JMML. Although the long‐term advantage of azacitidine therapy remains to be fully assessed, both decrease in spleen size and significant platelet responses observed demonstrate that the drug was effective in JMML and provided clinical benefit to patients with JMML in this study. This clinical trial has shown that azacitidine therapy prior to HSCT may be considered for patients with JMML.

Response of high-risk MDS to azacitidine and lenalidomide is impacted by baseline and acquired mutations in a cluster of three inositide-specific genes

Specific myeloid-related and inositide-specific gene mutations can be linked to myelodysplastic syndromes (MDS) pathogenesis and therapy. Here, 44 higher-risk MDS patients were treated with azacitidine and lenalidomide and mutations analyses were performed at baseline and during the therapy. Results were then correlated to clinical outcome, overall survival (OS), leukemia-free-survival (LFS) and response to therapy. Collectively, 34/44 patients were considered evaluable for response, with an overall response rate of 76.25% (26/34 cases): 17 patients showed a durable response, 9 patients early lost response and 8 patients never responded. The most frequently mutated genes were ASXL1, TET2, RUNX1, and SRSF2. All patients early losing response, as well as cases never responding, acquired the same 3 point mutations during therapy, affecting respectively PIK3CD (D133E), AKT3 (D280G), and PLCG2 (Q548R) genes, that regulate cell proliferation and differentiation. Moreover, Kaplan–Meier analyses revealed that this mutated cluster was significantly associated with a shorter OS, LFS, and duration of response. All in all, a common mutated cluster affecting 3 inositide-specific genes is significantly associated with loss of response to azacitidine and lenalidomide therapy in higher risk MDS. Further studies are warranted to confirm these data and to further analyze the functional role of this 3-gene cluster.