Search

Background: Allo HSCT is a potentially curative treatment in MDS which, in higher risk (IPSS high and int 2) MDS demonstrated an overall survival (OS) advantage over conventional treatment (especially HMAs) in retrospective (Koreth et al., JCO 2013) and prospective (Robin et al. leukemia 2015) studies. Retrospective studies, on the other hand, suggested no OS advantage for allo HSCT in lower risk MDS (IPSS low and int 1), except possibly in the "poorest" lower risk MDS subsets, as classified by the WPSS (Alessandrino et al. AMJH 2013) However, about 25% of lower risk MDS patients are reclassified as higher risk by the R-IPSS and a proportion of other lower risk MDS can also harbor some higher risk features that compromise their outcome. MDS-ALLO-RISK trial (clinicaltrial.gov NCT02757989), was designed to assess outcome of lower risk MDS patients with some high-risk features after HLA-matched donor HSCT. Method: The primary objective of this study was to demonstrate an OS improvement in lower risk MDS patients with some high risk features with a donor compared with those without a donor (with a 3 year OS of 70% versus 40%, respectively) . Inclusion criteria were: IPSS low or int1 MDS with at least one of the following characteristics: 1) R-IPSS intermediate or higher 2) RBC transfusion dependent anemia and failure to two or more treatments (including EPO, Lenalidomide or HMA ); 3) platelets < 20 G/L requiring transfusions 4) ANC < 0.5 G/L with severe infection 5) no contra indication to allo HSCT 6) age Results: 79 patients were included, 64 in group A and 15 in group B. Median age was 62.4 (IQR: 58-65) years in group A and 66 (IQR: 60.5-68) years in group B. Patients in group A were more frequently males (73 vs 40%, p=0.029), WHO was CMML in 8 (10%), MDS-SLD in 5 (8%), MDS-MLD in 9 (11%), MDS-EB1 in 41 (52%), MDS-RS in 12 (15%), unclassified in 4 (6%) without significant differences between the two groups. IPSS /IPSS-R was similar in both groups: IPSS low in 10% (11% in group A and 7% in group B) and Int-1 in 90%. IPSS-R: very low risk (6% vs 0%); low risk (25% vs 27%); intermediate (50% vs 47%); high (19% vs 27%); no very high risk. Among the 64 patients with a donor, 58 (92%) received HSCT, 2 died before HSCT; 2 had progressive disease and 2 are planned for HSCT. Transplanted patients received reduced intensity conditioning regimen with busulfan 6.4mg/kg, fludarabine 150mg/m2 and ATG (rabbit antithymocyte globulin therapy, grafalon®) 30mg/kg and cyclosporine-mycophenolate mofetil as GVHD prophylaxis. In group A, 21/64 had died, including 13 died from a non-relapse cause. In group B, 4/15 patients had died, 3 from MDS progression and one from CNS bleeding. Three-year OS was 60% (95%CI: 46.9-76.8) in group A and 64.2% (41.3-99.6) in group B (p=NS). At the time of analysis, 20 and 5 patients had progressed/relapsed in group A and B respectively. with a cumulative incidence of relapse/progression (from inclusion) of 27.4% (IC95%: 15;39.8) in group A and 41.7% (IC95%:9.2;74.2) in group B (p=0.71). Among the 58 transplanted patients, 11 (19%) died without disease progression, including one death from a solid tumor. 3 years non-relapse mortality in transplanted patients was 23.4% (IC95%:9.7;37). 3 years Incidence of grade 2 to 4 acute GVHD was 40.8% and 3 years chronic GVHD was 24.9%. Conclusion: In this, to our knowledge, first prospective study in IPSS lower risk patients with some unfavorable clinical or biological features, HLA identical donor (sibling or 10/10 unrelated) HSCT yielded a 3-year OS of 60%. Non relapse mortality was however 23%, and OS somewhat lower than expected (70% at 3 years) and similar to that observed in patients without a donor. Long-term follow-up is needed to better define subgroups of IPSS lower risk MDS that may benefit from allo HSCT. Disclosures Sebert: Abbvie: Consultancy; BMS: Consultancy. Cluzeau: Pfizer: Other: travel, accommodations, expenses; Astellas: Speakers Bureau; Amgen: Speakers Bureau; Agios: Honoraria; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel, accommodations, expenses, Speakers Bureau; Roche: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Speakers Bureau; Takeda: Other: travel, accommodations, expenses; Jazz Pharma: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria, Speakers Bureau. Loschi: AbbVie: Ended employment in the past 24 months, Honoraria; CELGENE/BMS: Honoraria; Gilead: Ended employment in the past 24 months, Honoraria; Novartis: Ended employment in the past 24 months, Honoraria; Servier: Ended employment in the past 24 months, Honoraria; MSD: Honoraria. Huynh: Jazz Pharmaceuticals: Honoraria. Ades: ABBVIE: Honoraria; NOVARTIS: Honoraria; CELGENE/BMS: Honoraria; CELGENE: Research Funding; JAZZ: Honoraria, Research Funding; TAKEDA: Honoraria. Fenaux: JAZZ: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Celgene/BMS: Honoraria, Research Funding; Syros Pharmaceuticals: Honoraria. Robin: NEOVII MEDAC NOVARTIS: Research Funding.

Background and aims: intensive chemotherapy (IC) has been used since the early 90's in the treatment of higher risk MDS, yielding 40 to 50% complete response (CR) but prolonged myelosuppression and 10 to 30% early deaths. IC is also recommended before allogeneic (allo) SCT when marrow blasts are increased (De Witte et al, Blood, 2017). CPX-351, a liposomal combination of cytarabine and daunorubicin, proved greater efficacy than classical IC with 3+7 in secondary-AML, including in patients with 20-30% marrow blasts and those who subsequently received allo SCT (Lancet et al, Lancet Haematol, 2021). We evaluated response to CPX-351 in a group of untreated higher risk MDS patients, most of whom were candidates for allo SCT. Methods: This prospective study, involving 12 GFM centers, included int-2 or high IPSS MDS, previously untreated with HMA or chemotherapy, and aged Results: 31 patients were included between July 2020 and January 2021. Median age was 62 years (range 31-69); WHO classification: 26 MDS-EB2, 5 CMML-2; IPSS: int-2: 84%, high: 16%; R-IPSS: intermediate: 29%, high: 55%, very high: 16%; karyotype: 2 very good, 22 good, 3 intermediate, 2 poor, 2 very poor. 27 patients received one induction cycle and 4 (in stable disease (SD) after the first cycle), a second induction cycle. Response rates, eventually evaluated a median of 53 days (range 28-112) from onset of induction, were with ELN 2017 criteria: CR: 52%, CRi: 13%, MLFS: 23%, SD: 13% and with IWG 2006 criteria : CR: 23%, mCR: 45%, mCR + HI-P: 6%, mCR + HI-P + HI-N: 6%, mCR + HI-N: 3%, PR: 3%, SD: 13%. Minimal residual disease assessment by NGS and flow cytometry will be presented at the meeting. 24/27 patients with baseline marrow blasts >10%, reached 20G/L and >50G/L were: 16 (range 0-55) days and 28 (range 8-51), respectively and to ANC >1G/L: 26 (range 2-60) days. Only one patient had grade ≥ 3 mucositis and 4 had grade ≥ 2 alopecia during induction treatment. No patient died during induction treatment or required management in the intensive care unit. With a median follow-up of 201 days (range 102-350), 22 of the 30 patients initially considered for allo SCT received transplant after no (10 pts), 1 (9 pts), 2 or 3 (3 pts) consolidation cycles and 5 are planned for allo SCT. Reasons for not being transplanted were, investigators' choice (n=1), relapse (1), no donor (1) and invasive fungal infection (n=1). None of the 4 non transplanted patients received consolidation cycles. Reasons for not receiving consolidation cycles were persistent cytopenia (n=5), cardiac toxicity (n=2), failure to achieve CR or PR (n=2). At the time of analysis (June 2021), 4 patients had relapsed, after 3 to 6 months of response. Conclusions : CPX-351 is effective in higher risk MDS/CMML, especially to achieve blast clearance, and as a bridge to allo SCT. Figure 1: waterfall plot according to IWG 2006 and ELN 2017 criteria Figure 1 Figure 1. Disclosures Fenaux: Novartis: Honoraria, Research Funding; Syros Pharmaceuticals: Honoraria; Takeda: Honoraria, Research Funding; JAZZ: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Celgene/BMS: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding. OffLabel Disclosure: CPX-351 use off-label for myelodysplastic syndroms in a prospective trial

Background: Systemic autoimmune and inflammatory diseases (SAIDs) occur in 10-15% of MDS or CMML patients. They are often severe, difficult to treat and steroid resistant/dependent disorders. In a retrospective report of 22 patients with steroid-dependent MDS/CMML associated SAID, we observed promising results with azacytidine (AZA) on the SAID component (Fraison et al, Leuk Res, 2016). In this prospective French nationwide trial, we aimed at confirming this effect prospectively. Patients and Methods: This open-label, single-arm multicenter, phase II study included MDS/CMML patients with IPSS/CPSS int 2 or high, or lower IPSS/CPSS but with significant cytopenias, especially ESA resistant anemia (or, for CMML, proliferative features) and SAID with steroid dependence and/or resistance. The primary endpoint was response rate (RR, including CR and PR) of SAID after 6 cycles of AZA. Secondary endpoints included RRof SAID after 3 cycles of AZA, response of MDS, time to MDS progression (including to AML), overall survival (OS) and safety. AZA was used at 75 mg/m²/d x 7 days, every 4 weeks for a minimum of 6 cycles (unless overt disease progression occurred before). At the onset of AZA, prednisone (PRED) was administered at 1 mg/kg during 1 month and then decreased progressively over 6 months. Results: 30 patients were included between July 2017 and June 2020 , 29 of whom received AZA and were considered evaluable: median age 72 [range 68-78], 69% males; WHO: MDS ML (n=11; 41%), CMML (n=11, 41%), MDS-RS (n=2, 7%), EB-1 (n=1) and EB-2 (n=1), unclassified (n=3); IPSS-R : good (n=15, 54%), very good (n=3; 11%, each), intermediate (n=7; 25%) and very poor profile (n=3; 11%) (all CMML had WBC 19 patients (65.5%, IC95% [45.7.82.1]) obtained a SAID response after 6 cycles (including 8 CR and 11 PR), while 17 (58.6% (IC95% [38.9; 76.5]) patients achieved an IWG 2006 hematological response (7 CR, 9 SD with HI and 1 marrow CR). All the 13 patients who received 12 cycles of AZA achieved SAID CR or PR at 12 months, and 10 of them had a hematological response (6 CR, 1PR, 2 HI, 1 marrow CR). The SAID response rate at 12 month was at 72.4% (IC95% : [51.3;85.6]). SAIDs complete/partial response occurred in 3/9 (33%) UBAI-positive versus 8/19 (42%) non-mutated cases. No significant prognostic factor of SAID response after 6 cycles, including sex, age, WHO classification, IPSS-R, UBA1 and TET-2 mutation status was found. With a median follow-up of 18.5 months [11.8; 24.3], 9 (31%) patients had died, with a 1-year OS of 82.3% (IC95% [69.4; 97.7]. At least one SAE occurred in 23 patients, with a median of 2 events/patient [1.5; 5.5]. Death was due to infection (n=5, two of them in patients with good IPSS-R, but severe steroid dependent SAID), MDS progression (n=2), or unrelated causes (n=2). Conclusion We confirmed prospectively an effect of AZA on the autoimmune/inflammatory component in two thirds of MDS/CMML patients with steroid dependent / refractory concomitant systemic autoimmune/inflammatory disease. No significant difference in AZA response was noted between UBA1 mutated and unmutated MDS patients. The adverse events and mortality rates, often from infectious origin, appear to be those expected in such an MDS population, potentially worsened by the associated SAID and background of immunosuppressive treatment (especially steroids) Disclosures Terriou: Alexion, AstraZeneca Rare Disease: Consultancy, Membership on an entity's Board of Directors or advisory committees. Vey: Amgen: Honoraria; BMS: Honoraria; BIOKINESIS: Consultancy, Research Funding; NOVARTIS: Consultancy, Honoraria, Research Funding; SERVIER: Consultancy; JAZZ PHARMACEUTICALS: Honoraria; JANSSEN: Consultancy. Ades: ABBVIE: Honoraria; TAKEDA: Honoraria; CELGENE/BMS: Honoraria; NOVARTIS: Honoraria; JAZZ: Honoraria, Research Funding; CELGENE: Research Funding. Fenaux: Abbvie: Honoraria, Research Funding; JAZZ: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Celgene/BMS: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Syros Pharmaceuticals: Honoraria.

Background: Ivosidenib (IVO) is an oral, targeted, small-molecule inhibitor of mutant IDH1 approved in the US for adult patients with unfit or relapse/refractory AML with IDH1 mutation. Little is known on its efficacy in patients with IDH1 mutated MDS. Here we report interim results of a Phase 2 study evaluating safety and efficacy of IVO in three different cohorts of MDS patients: Higher risk MDS having failed azacytidine (AZA) (cohort A, n=29), untreated higher risk MDS without life threatening cytopenias (ie ANC < 500/mm3 or any recent severe infections and/or platelets below 30,000/mm3 and any bleeding symptom,) as a first line treatment (cohort B, with the addition of AZA in non-Responders after 3 cycles, n=29) and lower risk MDS having failed EPO (cohort C, n=10). (ClinicalTrials.gov NCT03503409). Methods: Subjects enrolled in cohort A, B or C received continuous 28-day cycles of IVO - 500 mg orally QD. In cohort B, AZA (75 mg/m2/d x 7 days, SC) was added to IVO after 3 cycles, only in the absence of IWG 2006 response (absence of CR, PR or HI). The primary endpoint was overall hematological response rate (ORR) at 3 and 6 months (including CR, PR, stable disease with HI according to IWG 2006). All responders allowed to continue treatment until loss of response. Secondary endpoints included safety, duration of response, EFS, overall survival and translational project evaluating the role of biomarkers on response. We report the preliminary results on the first 26 pts enrolled. Results: At data cut off (6/15/2021), 32 patients had been enrolled, including 26 who were evaluable for the primary endpoint. 13, 11 and 2 were enrolled in cohort A, B and C respectively. Median age was 76 years and 50% were female. WHO was MDS-MLD, MDS-EB1, MDS-EB2, CMML and low blast count AML in 2, 2, 12, 1 and 9 patients respectively. IPSS-R was low, intermediate, high and very high in 2, 6, 5 and 13 resp. IDH1 mutation was p.R132C in 15 patients, p.R132H in 7, p.R132G/S in 3 and not specified in 1. The ORR was 69% (18 patients) including 12 CR (46%), 1 PR and 5 HI. Most patients achieved response after 3 cycles (17/18). Response was achieved in 7 (54%), 10 (91%) and 1 (50%) in cohort A, B and C respectively. Moreover, CR was achieved in 3, 8 and 1 in cohort A, B and C respectively. In cohort B, AZA was added to IVO in one patient after 3 cycles, without additional response. With a median follow up of 9.1 months, the median duration of response of the 18 responders was 7.4 months, 9 of them lost their response, and two had died without loss of response (from bleeding and after HSCT, respectively). IPSS-R was the only prognostic factor of response after 6 cycles. At data cut off, 12 patients had progressed (9 in cohort A, 2 in cohort B and 1 in cohort C) and 11 (42%, 10 in cohort A and 1 in cohort C) patients had died, mostly of relapse/progression (n=5/11), infection in 1, suicide in 1, hemorrhage in 1 and other unrelated causes in 3. Median overall survival was 14 months in the whole cohort, 7.7 and not reached in cohort A and B resp. The most common treatment-related serious adverse event (SAE) was differentiation syndrome (4/5), one died and three resolved without sequelae. One patient had febrile neutropenia related to IVO, resolved without sequelae. Conclusion: IVO was well tolerated in MDS patients with significant responses in all the cohorts. With a response rate of 91%, IVO was particularly effective in treatment naïve higher risk MDS patients with IDH1 mutations (cohort B). These encouraging preliminary results have to be confirm in more patients. The IDIOME study is still ongoing, and molecular monitoring results of IDH1 mutations will be presented. Disclosures Sebert: BMS: Consultancy; Abbvie: Consultancy. Cluzeau: Abbvie: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel, accommodations, expenses, Speakers Bureau; Agios: Honoraria; Amgen: Speakers Bureau; Takeda: Other: travel, accommodations, expenses; Astellas: Speakers Bureau; Jazz Pharma: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria, Speakers Bureau; Pfizer: Other: travel, accommodations, expenses. Stamatoulas Bastard: Pfizer: Other: Travel Support; Celgene: Membership on an entity's Board of Directors or advisory committees. Fenaux: Abbvie: Honoraria, Research Funding; JAZZ: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Celgene/BMS: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Syros Pharmaceuticals: Honoraria. Ades: Abbvie: Honoraria; Takeda: Honoraria; Novartis: Honoraria; JAZZ: Honoraria; Celgene: Honoraria, Research Funding.

*AK, PP shared first-, UP, HM, LA shared senior authors Introduction: Hypomethylating agents (HMAs) are the standard of care for patients with higher-risk myelodysplastic syndrome (HR-MDS) or acute myeloid leukemia (AML), not eligible for intensive chemotherapy or allogeneic stem cell transplantation. However, the majority of patients do not respond to these agents. Patients failing HMA therapy still have a dismal outcome with very limited treatment options available. Bemcentinib (BEM) is a selective small molecule inhibitor of AXL, a surface membrane protein kinase receptor mediating resistance to chemotherapeutic agents and decreased antitumor immune response. AXL is overexpressed on leukemic cells, especially in the stem cell compartment, and represents a potential novel target in patients with MDS and AML. Methods: The multicenter phase 2 BERGAMO trial evaluated the safety and efficacy of BEM in patients with HR-MDS or AML, refractory to or relapsing after at least six or four cycles of either azacitidine (AZA) or decitabine (DAC), respectively. Patients received an initial loading dose of 400mg BEM orally administered on d1-3 of cycle 1 and a maintenance dose of 200mg BEM on d4-28 of cycle 1 as well as on d1-28 in subsequent 28-day cycles. The primary endpoint was overall response rate (CR, CRi, PR or SD) assessed after 4 treatment cycles. All patients who achieved CR, CRi, PR or SD after 4 cycles of BEM were considered as responders and allowed to continue treatment for a total of up to 9 cycles. Non-responding patients stopped treatment after 4 cycles. Secondary endpoints of the trial included a translational project evaluating the role of biomarkers and response. Results: Between 2018 and 2020, 58 patients in 10 European centers were screened (MDS=27/AML=31) with a median age of 78 years (range, 62-86 years). 45 patients (MDS=21, AML=24) received at least one cycle of BEM and were eligible for safety and efficacy analysis after the first 4 months of treatment. Thirty six (80%) out of 45 patients were considered relapsed after a response to HMA, 8 (18%) had primary resistance and 1 patient (2%) had HMA intolerance. The median number of prior AZA or DAC cycles was 13. In addition, 18 patients (40%) (MDS=9/AML=9) were red blood cell transfusion-dependent. Treatment with BEM was generally well tolerated with only low rates of grade 3-4 hematologic toxicities (n=7). Forty-seven serious adverse events (SAE) occurred in 22 patients (MDS=9/AML=13), mostly due to infectious complications (n=12), hematological toxicity (n=4) or gastrointestinal disturbance (n=6). Until the first 4 months of BEM treatment, the median number of BEM treatment cycles received was 1.5 (range, 0.5-4). During study, 9 patients (20%) died due to infection (MDS=1/AML=3), deterioration of general condition (MDS=1/AML=2) and progressive disease (MDS=0/AML=2). BEM treatment is currently ongoing in four patients (MDS=3/AML=1). The primary endpoint was met in 9 of 45 patients (20.0%). Within the MDS cohort 33.3% achieved a response (n=7/21; CR=1, CRi= 3, SD=3), while 8.3% of patients (n=2/24) with AML achieved stable disease(SD). The 4 MDS patients achieving CR/CRi had a normal karyotype and a median baseline IPSS-R score of 4 (range 3-5). Among the MDS non-responders 4 patients had a complex karyotype, median IPSS-R score was 5 (range 3-5). Median baseline bone marrow blast count was 15% vs. 13% and median pretreatment hemoglobin-, platelet- and WBC levels were 9.2 g/dl (range 7.9-11.8 g/dl), 51 G/L(range 26-120 G/L) and 1.9x109/l (range 1.18-8.9 x109/l) vs. 9.6 g/dl (range 7.9-11.3 g/dl), 35 G/L (range 0-167 G/L) and 1.45x109/l (range 0.82-6.97 x109/l) comparing MDS responders (CR/CRi) vs MDS non-responders, respectively. Preliminary data evaluating soluble AXL (sAXL) in blood plasma at baseline showed that 66.6 % (n=2/3) of MDS patients achieving CR/CRi displayed sAXL levels below a defined threshold, while this was only seen in 20% (n=2/10) of MDS non-responders. Conclusion: These results of the prospective phase II BERGAMO trial confirm, that single agent BEM is generally safe and well tolerated in this patient population with an unmet medical need. Importantly, BEM showed clinical efficacy in a subgroup of MDS patients. These encouraging clinical results are being further explored by an in depth translational research program aiming to identify additional molecular and biological prognostic factors associated with response. Disclosures Kubasch: Celgene: Research Funding; Shire: Research Funding; Novartis: Research Funding. Cluzeau:Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Menarini: Consultancy; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Jazz Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees. Götze:Celgene: Research Funding. Teipel:janssen: Honoraria. Jentzsch:Novartis: Honoraria; JAZZ Pharmaceuticals: Honoraria. Giagounidis:Novartis: Membership on an entity's Board of Directors or advisory committees; AMGEN: Membership on an entity's Board of Directors or advisory committees. McPherson:BerGenBio ASA: Current Employment. van de Loosdrecht:novartis: Honoraria; celgene: Honoraria. Fenaux:Jazz: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding. Platzbecker:BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; Geron: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Honoraria, Research Funding. Medyouf:Bergenbio: Consultancy, Research Funding. Ades:Celgene/BMS: Research Funding; novartis: Research Funding; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; jazz: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding. OffLabel Disclosure: Bemcentinib is currently undergoing Phase II clinical trials for non-small-cell lung cancer (NSCLC), triple-negative breast cancer (TNBC), acute myeloid leukemia /myelodysplastic syndrome (AML/MDS), melanoma and metastatic pancreatic cancer. In 2019, FDA have granted fast track designation to bemcentinib for the treatment of elderly patients with acute myeloid leukemia (AML) whose disease has relapsed.

Context: Thrombocytopenia ( Methods: In this a phase I/II, open-label, single arm, multicenter study, key inclusion criteria were: WHO 2008 defined HMA-naive CMML, PLT < 50 x109/L, marrow blasts ≤ 5%, IPSS low/int-1 in MD-CMML, and in MP-CMML no or only 1 severity criteria (Hb < 10 g/dL, ANC > 16 x109/L, abnormal karyotype, extramedullary disease), spleen size < 16 cm. ELT was started at 100mg/d (amended to 50 mg/d) with escalating dose up to 300mg/d for at least 12 weeks. Primary endpoint was Platelet Response (HI-P) at 12 weeks, according to IWG 2006 criteria. Responders could continue ELT until protocol-defined progression, loss of response or toxicity. Results: Between August 2014 and September 2018, 30 pts (median age 77.5 years; M/F 22/8) including 21 MD-CMML and 9 MP-CMML were enrolled. 19 pts had CMML-0 and 11 pts CMML-1 with median PLT count of 32 x109/L (IQR 21-43 x109/L). 12 pts were PLT transfusion dependent (PLT-TD). In the 28 pts sequenced, TET2 mutation (mut) was found in 26 pts, RUNX1mut in 16 pts, SRSF2mut in 11 pts, ASXL1mut in 9 pts, signaling mut in 10 pts and PHF6mut in 5 pts. Median ELT dose at 12 weeks was 150 mg/d (IQR 100-262.5 mg/d). At 12 weeks, 14 pts (46.7%) achieved HI-P (95%CI 28 ; 66%) including 10 MD-CMML and 4 MP-CMML irrespective of PLT-TD status (p=0.46). Responders and non-responders mutational profile was comparable except that none of the 5 PHF6mut pts responded (p=0.06). Responders received ELT for a median of 33 weeks (IQR 17.3-49.5 weeks) with one responder still on therapy at 24 months. Median duration of response was 3.4 months (95%CI: 1.7-11.6 months). Loss of response were due to PLT decrease (11 pts) or transfusion (5 pts) and disease progression (3 pts). At 12 weeks, bleeding symptoms (all grades) were present in 3 (38%) non-responders and 4 (29%) responders. Clinical and biological grade≥ 3 adverse events (AE) were reported in 15 pts each. Before 12 weeks, 24 clinical and 16 biological AE occurred in 7 and 10 pts resp. Toxicity was cardiovascular, pulmonary or gastro intestinal in 2 pts each resp., hepatic and musculo-skeletal in 1 pt each and others in 3 pts. Biological toxicity was hepatic in 4 pts, electrolytic in 4 pts and others in 3 pts. Five pts discontinued ELT due to persistent drug related toxicity. No therapy-related deaths were reported. With a median follow-up of 17 months, 14 pts progressed (including 4 AML transformations) and 17 died. The12-month cumulative incidence of AML was 7% (95%CI: 1-21%). No factors were associated with risk of transformation in univariate analysis (neither WBC nor molecular mutational profile). Two-years OS and PFS were 47% (95%CI: 31-71%) and 28% (95%CI: 15-52%) respectively. Splice mutations were associated with better PFS in univariate analysis (HR=0.29, (95%CI: 0.11-0.76%); p=0.012). In the 21 CMML pts with PLT < 50 x109/L and ≤5% BM blasts from our previous CMML cohort (Itzykson JCO 2013) who were not exposed to ELT, the 12-month estimates cumulative incidence of AML was 10% (95%CI: 0-23%). Comparison with a larger historical cohort not exposed to ELT is ongoing. Conclusion: In CMML patients with severe thrombocytopenia and no marrow blast excess, treatment with ELT is safe and induces frequent but mostly transient responses without increasing the risk of CMML progression. ELT could thus help manage a situation at risk of bleeding such as a scheduled surgical procedure. Phase III studies may be useful to confirm the role of ELT in CMML patients with thrombocytopenia. Disclosures Rabian: Novartis: Honoraria; Jazz Pharmaceuticals: Honoraria. Thepot:astellas: Honoraria; novartis: Honoraria; sanofi: Honoraria; celgene: Honoraria. Braun:Daiichi Sankyo: Honoraria; Servier: Research Funding. Ades:jazz: Membership on an entity's Board of Directors or advisory committees, Research Funding; novartis: Research Funding; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Celgene/BMS: Research Funding. Solary:Janssen: Research Funding. Itzykson:Oncoethix (now Merck): Research Funding; Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Otsuka Pharma: Membership on an entity's Board of Directors or advisory committees; BMS (Celgene): Honoraria; Janssen: Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria; Sanofi: Honoraria; Amgen: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Honoraria; Abbvie: Honoraria; Stemline: Membership on an entity's Board of Directors or advisory committees.

Context. The perhaps only CMML-specific Randomized Clinical Trial (RCT) established hydroxyurea (HY) as the main treatment (Tx) for advanced proliferative CMML (Wattel Blood 1996). In Europe, the only hypomethylating agent (HMA) approved in CMML is AZA in non proliferative CMML-2. Phase 2 trials reported the activity of decitabine (DAC) in advanced proliferative CMML (Braun Blood 2011, Santini Leukemia 2018). We performed a RCT of DAC (±HY during the first 3 cycles) vs HY alone in those pts. Methods. The DACOTA trial (EudraCT 2014-000200-10) accrued pts with previously untreated (or < 6 weeks of HY), proliferative (WBC ≥ 13x109/L) CMML with advanced disease defined per Wattel et al as presence of extramedullary disease or ≥2 criteria among: BM blasts ≥5%, abnormal karyotype (except -Y), ANC ≥ 16x109/L, Hb < 10 g/dL, platelets < 100 x109/L or splenomegaly > 5 cm below costal margin. Pts were randomized 1:1 to DAC (20 mg/m2/d IV 5d/28d) or HY (1g/d, adjusted on WBC, 28d cycles) and treated until death, AML transformation or progression. The primary endpoint was EFS, events being death, transformation to AML, progression of myeloproliferation after 3+ cycles or progression of blasts and cytopenias after 6+ cycles. Response was assessed with IWG 2006 criteria modified to account for improvement of myeloproliferation, after central morphology review. Intent-to-treat analyses were done considering missing responses as failures. Results. From Oct 2014 to Sep 2019, 217 pts from 47 centers were screened and 170 randomized (84 DAC and 86 HY), including 12 pts (6 DAC and 6 HY) who never started Tx. Median age was 73 years (IQR 68-78). WHO was CMML-NA/1/2 in 2, 114 and 54 pts, respectively (resp). Median WBC 34.9 x109/L (IQR 22.9-55.7). Cytogenetic risk (Such Haematologica 2011) was fav 69%, int 12%, adv 18% NA 1%. Mutations in TET2, SRSF2, ASXL1 and signaling genes (CBL, JAK2, FLT3, KIT, NRAS, KRAS and CSF3R) were present in 64%, 51%, 62% and 57% resp. 72 pts had received HY for a median 27 days prior to randomization. Aside from older age in the HY arm (median 74 vs 71.5y in the DAC arm), there was no imbalance between Tx arms. DAC and HY pts received a median of 5 (IQR 3-12) and 6 (IQR 3-14) cycles, resp. As of 15th June 2020, 5 and 10 DAC and HY pts were still on Tx. Reasons for Tx cessation in the DAC arm were death (n=19), AML transformation (n=16), progression (n=9) , hematological toxicity (n=13) or other (n=21). Reasons for Tx cessation in the HY arm were death (n=14), AML transformation (n=13), progression (n=18), hematological toxicity (n=6) or other (n=20). 126 and 85 pts received 3 and 6 cycles, resp. In the ITT population, ORR at 3 cycles was 56% (7CR, 25 mCR±HI, 15 SD+HI) and 30% (0 CR, 8 mCR±HI, 18 SD+HI) in the DAC and HY arms, resp (p=0.0011) and ORR at 6 cycles was 32% (6 CR, 9 mCR±HI, 12 SD+HI) and 17% (2 CR, 4 mCR±HI, 9 SD+HI) in the DAC and HY arms, resp (p=0.033). Median response duration was 15.9 vs 18.2 months (mos) in the DAC and HY arm, resp (p=0.81). Infection and hemorrhage occurred at least once in 49% and 31% of pts, resp. 55% of DAC pts and 38% of HY pts required hospitalization at least once (p=0.05). Non-heme ≥ grade 2 AEs occurred in 79% and 63% of DAC and HY arms, resp (p=0.03). Grade ≥3 cardiac AEs occurred in 13 DAC and 4 HY pts, resp. With a median follow-up of 13.9 mos, median EFS was 12.6 vs 10.3 mos in the DAC and HY arms, resp (reference DAC arm, HR= 1.14 CI95 0.8-1.64, p= 0.46). Median AML-free survival (AMLFS) was 13.6 and 15.8 mos in the DAC and HY arms resp (p=0.86). Median OS was 18.4 and 23.1 mos in the DAC and HY arms, resp (p=0.72). Considering death and AML transformation as competing risks there was no significant difference in cumulative incidence of AML (p=0.1) or death without transformation (p=0.06) between arms. 30 pts from the HY arm received an HMA (DAC n= 13, AZA n= 16, both=1) after study exit. Censoring at HMA onset in the HY arm, median OS was 18.4 vs 30.4 in the DAC and HY arm, resp (p=0.15). 13 pts were transplanted (DAC n= 10, HY n= 3). There was no interaction between Tx arm and CMML-0/1 vs -2, platelets ≥ vs 0.05). Conclusion. RCTs are feasible in advanced proliferative CMML, which remains an unmet medical need. In these pts, DAC did not provide an overall or event-free survival advantage over HY. HY remains a valid option in advanced proliferative CMML. However, one third of HY pts subsequently received an HMA and more DAC pts achieved a response and were bridged to HSCT. Figure Disclosures Itzykson: Abbvie: Honoraria; Daiichi Sankyo: Honoraria; Otsuka Pharma: Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria; Sanofi: Honoraria; BMS (Celgene): Honoraria; Janssen: Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Stemline: Membership on an entity's Board of Directors or advisory committees; Amgen: 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; Oncoethix (now Merck): Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Santini:BMS, J&J, Novartis: Honoraria; Acceleron, BMS, Menarini, Novartis: Consultancy; Takeda, Pfizer: Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding. Lionel:Abbvie: Consultancy; Takeda: Consultancy; Celgene/BMS: Consultancy, Research Funding; Novartis: Consultancy; Jazz: Consultancy, Research Funding. Thepot:astellas: Honoraria; novartis: Honoraria; sanofi: Honoraria; celgene: Honoraria. Giagounidis:AMGEN: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Luebbert:Janssen: Research Funding. Park:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Other: Travel expenses. Stamatoulas Bastard:Pfizer: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Celgene: Honoraria; Takeda: Consultancy. Solary:Janssen: Research Funding. Platzbecker:Novartis: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria; Amgen: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Geron: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Fenaux:Novartis: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Jazz: Honoraria, Research Funding. OffLabel Disclosure: Decitabine for CMML with WBC > 13 x109/L.

Background: MDS-RS are associated with a low risk of Acute Myeloid Leukemia (AML) progression and prolonged survival in most cases, but recurring anemia whose treatments, including Erythropoiesis Stimulating Agent (ESA), Lenalidomide, hypomethylating agents (HMAs), Luspatercept, and experimental drugs generally have transient effect and/or are not widely available. MDS-RS patients thus eventually have regular Red Blood Cells (RBC) transfusion dependency (TD) associated with mean low hemoglobin levels, and chronic anemia responsible for reduced quality of life, cardiovascular complications, and iron overload with organ dysfunction. We performed a retrospective observational study to describe transfusion characteristics and costs, along with clinical events, in a French population of RBC TD MDS-RS patients. Methods: Adult RBC-TD patients with MDS-RS from 12 hematology departments of the GFM were included. The number of RBC concentrates transfused was assessed over the last 6 months (during which no other treatment than transfusions was received), and patients categorized in low transfusion burden (LTB: 3 to 7 RBC/16 weeks) and high transfusion burden (HTB: ≥8 RBC concentrates /16 weeks). Data about iron chelation, full time hospitalization (differing from day care facility stays for programmed transfusions), causes of hospitalization, treatment of anemia before inclusion and transfusion costs was collected. Results: 100 patients MDS-RS were included, with a median time from diagnosis of 5 years (1 to 21 years). Median age was 78 years (57 to 99). Patients had received a median of 2 lines of treatment (including an ESA in 97% of them). 21% had LTB and 79% HTB. HTB patients had a longer disease duration, more frequent iron chelation (82% versus 50% in LTB patients, p=0.0052) and higher serum ferritin at inclusion (median 1958 µg/l versus 1176 µg/l, p=0.03). During the 6-month study period, 22% of the patients required full time hospitalization (in addition to day care facility for transfusions), including 25% of patients with HTB and 15% with LTB, and 43% during overall disease follow-up. Causes of full time hospitalization (figure) were symptomatic anemia (41%), general condition degradation (5%) or cardiac disease (8%), to both of which anemia potentially contributed, infection (23%), bleeding (8%), pulmonary (2%), 13% for other reasons. 15 HTB patients versus 1 LTB patient were hospitalized for symptomatic anemia. The 6-months average transfusion costs, including cost of the day care facility for RBC transfusion, transportation to and from the hospital, lab tests and iron chelation were $21459/patient, excluding costs of full-time hospitalization for complications. The average cost in HTB and LTB patients was $22829 and $7586/patient, respectively. Conclusion: Most MDS-RS patients currently become RBC-TD, often during several years, and most have high transfusion burden. The average cost of RBC transfusions and iron chelation was $21459/ 6 months. During this short observation time, 22% of the patients required full time hospitalization, due to complications of anemia in at least 50% of the cases, which also increased costs (comparison with rates of hospitalization in an age and sex matched general population will be presented). Poor quality of life associated with chronic anemia should also be taken into account in those RBC-TD patients. Widely available treatments, capable of avoiding RBC transfusion dependence and improving mean hemoglobin levels, are required in those MDS-RS patients. Disclosures Cony-Makhoul: BMS: Speakers Bureau; Incyte Biosciences: Speakers Bureau; BMS: Consultancy; Novartis: Consultancy; Pfizer: Consultancy. Thepot:astellas: Honoraria; novartis: Honoraria; sanofi: Honoraria; celgene: Honoraria. Cluzeau:Celgene: Membership on an entity's Board of Directors or advisory committees; Jazz Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Menarini: Consultancy; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Stamatoulas Bastard:Takeda: Consultancy; Pfizer: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Celgene: Honoraria. Fenaux:Jazz: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; BMS: Honoraria, Research Funding. Park:Pfizer: Other: Travel expenses; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees.

Introduction : TP53 mutated (TP53m) MDS and AML have very poor outcome irrespective of the treatment received, including 40% responses (20% CR) with azacitidine (AZA) with short response duration and a median overall survival (OS) of about 8 months (Bejar, Blood 2014). APR-246 is a prodrug spontaneously converted to methylene quinuclidinone (MQ), a Michael acceptor that binds covalently to cysteines in mutant p53, leading to protein reconformation that reactivates its pro apoptotic and cell cycle arrest functions. The combination of AZA and APR 246 showed promising results in a phase Ib study in TP53m MDS (Sallman, ASH 2018). We report interim results of a GFM phase 2 study of AZA+ APR-246 in TP53m MDS and AML, conducted in parallel with a similar US MDS consortium study. Patients and Methods : The study included hypomethylating agent (HMA) naïve and not previously allografted intermediate, high or very high IPSS-R TP53m MDS and AML adult patients. Patients received APR-246 4500 mg IV /d (6 hour infusions) (days 1-4) followed by AZA 75 mg/m²/d (days 4-10) in 28 day cycles. Response (primary endpoint, assessed by IWG 2006 for MDS and ELN criteria for AML) was evaluated after 3 and 6 cycles in the intent to treat (ITT) population, ie all patients who had received any protocol treatment, and in patients who had at least a blood and bone marrow evaluation after cycle 3 (evaluable population). Allo-SCT, when possible, was proposed after 3 to 6 cycles, and treatment with reduced APR 246 and AZA doses could be continued after allo-SCT. Results : 53 patients were enrolled between Sept 2018 and July 2019 in 7 GFM centers, with a median age of 73 years (range 44-87), and M/F: 28/25. 34 patients had MDS (including 74% very high IPSS-R) and 19 had AML. IPSS-R cytogenetic risk was very poor in 30/34 MDS, and unfavorable in 18/19 AML, complex in 89% of the patients. Median baseline mutated TP53 VAF was 21% (range 3-76). Nineteen of the 53 patients had been included at least 7 months before date of analysis (25 July 2019), had received protocol treatment and were thus potentially evaluable for response after 6 treatment cycles (ITT population). One of them died after only one cycle from an unrelated cause (cerebral ischemic stroke), and 2 during the third cycle (from bleeding and sepsis, respectively). In the remaining 16 patients (evaluable population per protocol), the response rate was 75% including 9 (56%) CR, 3 (19%) marrow CR or stable disease with hematological improvement (HI), and 4 treatment resistance. In the ITT population, the response rate was 63%, including 47% CR, and 16% stable or marrow CR+ HI. Among CR patients, complete cytogenetic CR and negative NGS for TP53 mutation (VAF cutoff of 2%) were achieved in 7/9 (78%) and 8/8 (100%), respectively. So far, 1 patient has undergone allo-SCT. All 53 patients had received at least one treatment cycle, and no increased myelosuppression, compared with AZA alone, was apparent. Treatment related AEs observed in ≥ 20% of patients were febrile neutropenia in 19 (36%) and neurological AEs in 21 (40%) of the patients. The latter, reviewed with a neurological team, were mainly grade 1 or 2 and consisted of ataxia (n=13), sometimes associated with cognitive impairment (n=4), suggesting a cerebellar origin. Other patients experienced acute confusion (n=4), isolated dizziness (n=3) and facial paresthesia (n=1). Neurological AEs reached grade III in 3 cases (1 acute confusion, 2 ataxia). Occurrence of neurological AEs was correlated with lower glomerular filtration rate at treatment onset (p Conclusion : In this very high-risk elderly population of TP53m MDS and AML, generally with complex karyotype, a promising 56% CR rate at 6 cycles was reached in the evaluable population with AZA+ APR 246 combination, with deep molecular remission in all CR patients. We observed manageable neurologic AEs, mainly in elderly patients with reduced renal function, who therefore require close monitoring and dose reduction if necessary. An update regarding safety and efficacy in the 53 patients, including survival data, will be available at the meeting. A phase III international trial comparing AZA alone and AZA+ APR 246 in TP53m MDS is ongoing. Disclosures Cluzeau: Abbvie: Consultancy; Jazz Pharma: Consultancy; Menarini: Consultancy. Peterlin:AbbVie Inc: Consultancy; Astellas: Consultancy; Jazz Pharma: Consultancy; Daiichi-Sankyo: Consultancy. Recher:Daiichi-Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; chugai: Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Astellas Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Stamatoullas:Celgene: Honoraria; Takeda: Consultancy. Berthon:JAZZPHARMACEUTICAL: Other: DISCLOSURE BOARD; CELGEN: Other: DISCLOSURE BOARD; PFIZER: Other: DISCLOSURE BOARD. Sallman:Celyad: Membership on an entity's Board of Directors or advisory committees. Ades:Amgen: Research Funding; Astellas: Membership on an entity's Board of Directors or advisory committees; Silence Therapeutics: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Helsinn Healthcare: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Fenaux:Celgene Corporation: Honoraria, Research Funding; Astex: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Aprea: Research Funding.

Introduction Recently, progress has been made in the treatment of patients with higher risk myelodysplastic syndromes (HR MDS) and acute myeloid leukemia (AML). Nevertheless, patients failing hypomethylating agents (HMA) have a dismal prognosis and very limited treatment options. Targeting CD123 on leukemic stem cells (LSC) is one promising approach in MDS and AML. Talacotuzumab (TAL, JNJ-56022473) is an IgG1 monoclonal antibody targeting CD123 preferentially via antibody-dependent cellular cytotoxicity (ADCC) mediated by natural killer cells (NKs). Aim The SAMBA trial, a phase II study of the German and French MDS study groups within the EMSCO network assessed the overall hematological response rate after 3 months of single agent TAL treatment in AML or HR MDS patients failing hypomethylating agents (HMAs). Methods TAL was given IV at a dose of 9 mg/kg once every two weeks for a total of 6 infusions, responders received up to 20 additional infusions. After the first 3 months, overall hematological response rate (either CR, PR, marrow-CR, HI, SD) was evaluated by bone marrow biopsy. The study was accompanied by an immune monitoring via flow cytometric analysis to investigate the distribution of T- and NK cells in peripheral blood (PB) and bone marrow (BM) at the time of screening and during therapy in comparison with healthy, age-matched controls. Results 24 patients (19 AML and 5 HR MDS) with a median age of 77 (range 71-90) years, who either failed to achieve complete- (CR), partial response (PR), hematological improvement (HI) or relapsed after HMA therapy were included in the study. After TAL administration, 14 patients could be assessed for response after 4 infusions and 10 patients after 6 infusions. The overall response rate (ORR) was 20.8% including 1 complete remission (CRi), 1 patient with hematologic improvement (HI-E) and additionally 3 patients with disease stabilization. The median duration of response in these patients was 3 months (range 3-14 months). Two patients are still on treatment, one patient despite losing objective response (14 months) and one patient with disease stabilization (13 months). The median overall survival for the entire cohort of patients was 3.2 months (range 0.4-11.2 months). In 10 patients (41.6%), therapy with TAL resulted in grade 3/4 infusion related side effects (pneumonia, n=1; infusion-related reaction, n=8; septic shock, n=1). Before treatment initiation, patients had lower levels of CD56dim NK-cells in PB (82% vs. 89% of NK-cells; p=0.069) expressing significantly more inhibiting NK-cell receptors like KIR2DL2 (8.8% vs. 3.2% of NK-cells; p We could not detect any difference in NK-cell levels in responding patients compared to non-responders. Interestingly, pre-treatment expression (MFI and percentage) of CD123 on immature myeloid derived suppressor cells (iMDSC) was higher in responders than in non-responders (p Conclusion Single agent TAL has limited efficacy in patients with advanced myeloid malignancies failing HMA. Expression of CD123 on immature MDSCs might serve as a biomarker of response for future anti-CD123 targeted approaches. Disclosures Götze: Celgene: Honoraria, Research Funding; JAZZ Pharmaceuticals: Honoraria; Novartis: Honoraria; Takeda: Honoraria, Other: Travel aid ASH 2017. Krönke:Celgene: Honoraria. Middeke:Roche: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Fenaux:Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Otsuka: Honoraria, Research Funding. Schlenk:Pfizer: Research Funding, Speakers Bureau. Ades:JAZZ: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees; silent pharma: Consultancy; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Platzbecker:Celgene: Research Funding.

Background: Hypomethylating agents (HMAs) have become the reference treatment of higher risk MDS, but the median survival of about 2 years obtained with AZA remains modest, and median survival after HMA failure is only about 6 months (Prébet et al, JCO 2011). Guadecitabine (GDAC, SGI-110) is a novel HMA dinucleotide of Decitabine and deoxyguanosine, administered SC, which results in extended DAC exposure. In a phase I-II study in AML (Issa, Lancet Oncol, 2015) a dose of 60mg/m2/day for 5 consecutive days was recommended. We designed a national multicenter phase II study evaluating the efficacy of GDAC in higher-risk MDS patients, refractory or relapsing after AZA (NCT02197676). Methods: Main inclusion criteria were (1) IPSS int-2 or high MDS, or CMML with WBC < 13 G/l and marrow blasts > 10%, or AML with 20-30% marrow blasts (2) Refractory to 6 cycles of AZA or relapsing after response, but without overt progression (i.e., greater than doubling of marrow blasts compared to pre AZA values) (3) Age ≥ 18 years (4) Normal liver and renal functions. Patients received GDAC 60mg/m2/d x5 d every 28 d until progression, death or no response after 6 cycles (extended to 9 cycles after the 20 first pts). Global DNA methylation was assessed at baseline and on d 8, 15, 22 and 28 of cycle 1 in blood, and on d 28 of cycles 1 , 3 and 6 in BM and blood ,using bisulfite-converted DNA followed by pyrosequencing technology measuring 3 representative CpG sites of the LINE-1 promoter region. An intent-to-treat analysis was performed on June 2016, with a median FU of 9.6 months Results: Between Aug 2014 and Jan 2016, 56 pts from 13 centers were enrolled, M/F: 37/19, median age 75 years [IQR, 69-76]. 15 patients had primary resistance after 6 cycles of AZA, and 41 patients had relapsed after a response and a median of 13 AZA cycles [IQR 9.75-23]). 15 pts had IWG 2006 progression between onset of AZA and inclusion. At inclusion, WHO classification was RCMD in 2 pts, CMML in 1 pt, RAEB-1 in 11 pts, RAEB-2 in 31 pts and AML in 11 pts; . IPSS was int-1, int-2 and high in 4 (6%), 27 (50%) and 23 (42%) pts, resp. (2NA), and R-IPSS was low, int., high and very high in 1 (2%), 3 (6%), 13 (26%), and 34 (60.7%) pts resp (5NA). 43 (77%) pts were RBC transfusion-dependent (TD) and ECOG was >1 in 5 (9%) pts. The average baseline LINE-1 methylation level in the 45 pts evaluated was 73% in blood and 72% in BM. One pt died before any treatment, and 55 patients received at least one cycle of GDAC, with a median of 3 cycles [IQR, 2-5.5]. 9 pts responded (8 after 3 cycles) with 1 (3%) CR, 2 (5%) CRp, 5 (14%) marrow CR and 1 HI; ie an ORR of 16% (95%CI, 8-28%). Responses were seen in 4/15 (26.6%) primary refractory, and in 5/41 (12.2%) relapsing patients (p=NS). On average, the maximum LINE-1 demethylation occurred during the first cycle on day 8 in blood (median -11.3%), and on day 28 in BM (median -3.1%). Median duration of response was 9 months including so far 2 responses ≥ 1 year (12 and 18 months). 49 SAE occurred in 44 pts, and were mostly hematological, with myelosupression in 35/56 (63%) of pts 49 patients ended the study, because of progression (n=20), death (n=14), investigator or patient decision (n= 8), toxicities (n= 6) and pt withdrawal (n=1). Median OS from inclusion was 6.7 months (IC95% [5.6-11.8]). 33 pts had died, because of MDS progression in 14 (42%), infection in 13 (39.3%), bleeding in 1 (3%), and other causes in 5 (15%) pts (2 UK, 2 general deterioration, 1 heart attack). No significant prognostic factor of response to GDAC, including age, sex, ECOG, TD, baseline Hb, platelet, ANC, marrow blast %, cytogenetics, IPSS, IPSS-R, type of AZA failure (primary or secondary), LINE1 baseline methylation or demethylation rate was found. OS was significantly shorter in pts with high IPSS (HR=2.1, 95%CI, 1.04-4.20, p=0.04), and with very poor IPSS-R cytogenetics (HR=4.3, 95%CI, 2.0-9.1, p=0.0015), the latter remaining prognostic in multivariate analysis. Using the recent prognostic model for MDS pts having failed HMA (Nazha et al, hematologica 2016), that includes ECOG>1, very poor cytogenetics, age, marrow blasts >20%, TD, platelets Conclusion: Response rates with GDAC, in this population of higher risk MDS, CMML or low blast count AML with failure to AZA (and often with IWG 2006 progression) were modest. Tolerance was similar to that of conventional HMA treatment. Disclosures Beyne-Rauzy: Celgene, Novartis: Honoraria. Park:Novartis: Research Funding. Jueliger:astex: Employment. Bevan:astex: Employment. Ades:Celgene, Takeda, Novartis, Astex: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Fenaux:Celgene, Janssen,Novartis, Astex, Teva: Honoraria, Research Funding.

Background: Hypomethylating agents, especially AZA, have become the reference treatment of higher risk MDS, but the median survival of about 2 years obtained with AZA remains modest, and must be further improved. In addition, AZA yields only about 30% of marrow responses (including CR+PR+marrow CR). Intensive chemotherapy combining Idarubicin (IDA) and AraC yields 30 to 50 % CR in higher risk MDS (Beran and all, cancer 2001) and IDA, as single agent, induces about 30% CR in elderly AML patients (Carella, haematologica 1990). We designed a phase I/II study evaluating the safety and efficacy of the combination of AZA and IDA (1 day during each AZA cycle) in higher risk MDS patients (NCT01305135). Methods: Main Inclusion criteria were: (1) IPSS int-2 or high MDS, or CMML with WBC < 13 G/l and marrow blasts > 10%, or AML with 20-30% marrow blasts (2) Age ≥ 18 years (3) Performance Status (PS) Results: Between Dec 2010 and Jan 2014, 41 patients (from 13 centers) were enrolled, including 13 women and 28 men with a median age of 74 years [IQR 70; 76]. At inclusion, WHO classification was RCMD in 1 pt, CMML in 2 pts, RAEB-1 in 10 pts, RAEB-2 in 13 pts, AML in 12 pts and unclassified MDS in 3 pts. Median marrow blast % was 9.5 [IQR: 6-19.9] and karyotype according to IPSS was favorable in 12 (29%), intermediate in 9 (22%) and unfavorable in 18 pts (44%) (2 cytogenetic failures). IPSS was int-2 and high in 56% and 44%, respectively. PS was 0 in 39%, 1 in 55% and 2 in 6% pts. 10 patients received 5 mg/m2 of idarubicin (cohort 1) and 31 received 10 mg/m2 (cohort 2). 375 cycles of AZA were administered (219 of them with AZA+IDA, as IDA was used only for the first 9 cycles), with a median number of 6 cycles/patient (median 6 in the IDA 5 mg/m2 cohort and 4 in the 10 mg/m2 cohort (p=0.9). Of the 41 patients enrolled, 20(48.8%, 95%CI: 32.9-64.9) achieved response (6 CR, 7 PR, 4 mCR and 3 stable disease with HI) with no difference between the two cohorts (50% vs 48%) and a marrow response rate (CR + PR + mCR) of 41,5%. Thirteen of the 22 patients with abnormal karyotype were evaluable for cytogenetic response: 5 achieved cytogenetic response (4 complete, 1 partial), 1 in cohort 1 and 4 in cohort 2. With a median follow up of 14 months, 9 of the 20 responders had relapsed. Median response duration was 11 months [3.2-42.7], with no difference between the two cohorts. Median OS was 14.3 months [IC95%: 12.5; NA] and 2y OS was 24.8%, with no significant difference between the 2 cohorts (p=0.43). By univariate analysis no baseline parameter including gender, karyotype, marrow blast %, IPSS and IDA dosage (5 or 10 mg/m2), had any significant impact on response or survival. 45 SAEs were reported in 26 patients, including febrile neutropenia (n=25), bleeding (n=7) and 2 non-clinically significant reductions in left ventricular ejection fraction (1 transient, and 1 persisting without symptoms). The number of infections per cycle [9/85 (10%) in the IDA 5 mg/m2 arm and 38/281 (14%) in the IDA 10 mg/m2 arm] and the number of bleeding events (9% vs 17%) did not significantly differ between the two cohorts. Conclusion: In our experience, Idarubicin (on day 8 of each cycle) can be combined to Azacitidine without any additional toxicity. The marrow response rate obtained with the combination (41.5%) may be higher than with AZA alone. We are currently comparing in higher risk MDS patients this AZA-IDA combination versus AZA alone (and other combinations of AZA with other drugs) in a prospective randomized GFM trial. Disclosures Sebert: Celgene: Research Funding. Fenaux:Celgene: Research Funding.

Background: Azacitidine (AZA) is the current standard of care for patients treated for higher risk MDS, but 40-50% patients do not respond and most responders eventually relapse. Median survival after AZA failure is only 5 months and no standard of care is defined for this population. Preclinical studies and positive results of phase I-II trials support a synergistic effect of the histone deacetylase (HDAC) vorinostat (VOR) and AZA in terms of response, although no survival advantage of the combination has as yet been demonstrated. We hypothesized that adding VOR to AZA in patients with primary or secondary AZA resistance could rescue response and prolong survival. Methods: inclusion criteria inGFM AZAVOR study (NCT 01748240) were: 1/IPSS int 2 or high risk MDS at the time of initiation of AZA 2/treatment with at least 6 cycles of AZA and either failure to achieve any response or loss of response (per IWG2006 criteria) 3/a maximum of 3 months between AZA failure and inclusion with no other treatment in between. Patients received VOR 300mg bid from day 3 to day 9 of each cycle. AZA was given at standard 75mg/m2/d day 1 to 7 or at the maximum previously tolerated dose in case of dose reduction. Patients were evaluated after 6 cycles and responding patients treated until progression. The trial used a two-stage design, and accrual was to be stopped if less than 3 responses were seen in the first 14 evaluable patients. Results 21 patients were included between march 2013 and September 2014. Nineteen patients were treated (1 patient died and 1 progressed before treatment). Median age was 72 years. All pts had higher risk MDS and had received a median of 6 cycles of AZA before entering the trial. The median number of AZA+ VOR cycles administered was 3 (range: 1-12). No unexpected SAEs were seen, and the most common AEs were infection, thrombocytopenia, GI toxicities, and fatigue. After 6 cycles of treatment, only 2 patients (11%) achieved response (1 erythroid hematological improvement, 1 partial remission), , which, per protocol, triggered the stop of accrual. At last follow-up, 18 patients were off study and one patient was still on treatment. Nine patients stopped treatment because of progression (42%), 4 stopped treatment for lack of response (21%), 2 stopped treatment because of intolerance (11%), 1 patient stopped at his request (5%), and 1 patient died of complications of cytopenias while on treatment (5%). Median overall survival was 13 months. Conclusion This is the first report of an add-on study in high risk MDS, a strategy that may be useful for the early evaluation of drugs for which synergy with AZA is expected. Our results show that the proposed regimen of AZA +VOR can be used safely. However, the observed response rate was not above the "background" response rate expected from AZA alone continuation in a comparable patient population, indicating that the addition of VOR cannot reverse resistance to AZA. Disclosures Prebet: CELGENE: Research Funding. Off Label Use: lenalidomide. Wattel:Janssen: Consultancy, Honoraria, Research Funding; PIERRE FABRE MEDICAMENTS: Research Funding; CELGENE: Research Funding, Speakers Bureau; NOVARTIS: Research Funding, Speakers Bureau; AMGEN: Consultancy, Research Funding. Cony-Makhoul:Novartis: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau. Fenaux:Amgen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Celgene Corporation: Honoraria, Research Funding. Vey:Janssen: Honoraria; Roche: Honoraria; Celgene: Honoraria.

Abstract 1719 Background Prognostic of IPSS high and int-2 risk MDS after azacitidine failure or relapse is very poor, with a median survival < 6 months (Prebet, JCO 2011). We previously showed that Erlotinib (ERLO), an oral inhibitor of EGF-R tyrosine kinase approved for the treatment of several solid tumors, also has “off target” in vitro effects in myeloid leukemic cell lines and primary blast cells of higher risk MDS and AML (Boehrer, Blood 2008). ERLO induced, cell cycle arrest, myeloid differentiation, apoptosis and also reduced the growth of xenografted human AML cells. We therefore assessed safety and efficacy of ERLO in higher risk MDS with AZA failure in a phase I/II trial. Methods This trial (NCT 01085838), conducted by the GFM, had the following inclusion criteria: (1) MDS according to WHO classification (also including RAEBt /AML with 20–30% blasts), (2) IPSS Int-2 or High, (3) marrow blasts >10% and Results Between July 2010 and July 2012, 29 patients (19M, 10F) were included in 9 centers. Median age was 77 years (range 65–85). Median number of cycles of AZA before inclusion was 18 (5–41). Before AZA, 6 pts had received intensive chemotherapy (with 3 CR, 1 PR and 2 failures) and 1 Lenalidomide, without response. At inclusion, 17 pts had RAEB-2 and 12 had RAEB-t/AML with 20–30% blasts. IPSS cytogenetic risk was poor in 6 pts (21%) including 5 complex, intermediate in 9 pts (31%) and good in 8 pts (38%, all normal karyotype), while 6 pts had cytogenetic failure. During the phase I part, five patients received ERLO at 100 mg/day, and 5 pts ERLO at 150 mg/d. After review of toxicities by the independent DSMB, the ERLO dose of 150 mg/d was retained for the phase II part, that included 19 patients, of who 7 had not yet completed 12 weeks of treatment and were too early for evaluation. Overall, 22 patients were evaluable (including 6 AZA failure and 16 relapses after response to AZA) 5 of them had early death (before week 12) due to disease progression (n=2), sepsis (n=3) and 9 additional pts stopped treatment before week 12 due to grade 2 skin rash (n=2), bleeding (n=1), fatigue (n=1), investigator's decision(n=1), consent withdrawal (n=1), disease progression (n=3). Three patients, ie 13.6% of the 22 evaluable, and 37.5% of the 8 pts who received at least 12 weeks of treatment achieved IWG2006 response (2 at 100mg/d and 1 at 150 mg/d) including 1 marrow CR, 2 hematological improvement (1 HI E and 1 HI P). Six pts had stable disease without HI, and 13 pts progressed. All 3 responders had RAEB-2, with normal, int and failed karyotype, respectively. Two had received intensive chemotherapy before AZA (with 1CR and 1PR), 2 had relapsed after AZA response and 1 had not responded to AZA. Response duration was 3.4 (pt with marrow CR) 5.3 and 11.7+ months, respectively. Survival of the 3 responders from inclusion was 6.1,15 and 14.5 + months, respectively. Median OS from inclusion was 4 months. In the 100 mg/day cohort, 7 SAE occurred (3 sepsis, 1 grade I liver toxicity, 1 FUO and 1 grade III anorexia). No hematological toxicity was described and no DLT was seen. In the 150 mg cohort, 5 SAE occurred (3 sepsis, 1 bleeding and 1 grade III diarrhea). The most common toxicities reported were grade I rash (80%) and grade I diarrhea (30%). Bone marrow cells were collected in all the patients at inclusion and at week 12, and study of in vivo ex vivo correlations is in progress. Conclusion Erlotinib at 100 to 150 mg/ d is well tolerated in higher risk MDS resistant to AZA. A few (13.6% in the whole cohort ) significant responses occurred including 1 marrow CR, 1 HI E and 1 HI P. Based on our previous in vitro work showing that ERLO can potentiate the effect of AZA on MDS and AML cells, particularly by inhibiting drug efflux via ABC transporters. (Lainey et al, ASH2010,abstract 974,) combinations of AZA and ERLO could be considered in the treatment of higher risk MDS. Disclosures: Off Label Use: Erlotinib is approved to treat non small cell lung cancer and pancreatic cancer.

Abstract 4003 Introduction: Azacytidine (AZA) has significantly improved the management and survival of patients (pts) treated for high risk myelodysplastic syndrome (MDS). However, 40 to 50% of patients will not achieve any kind of response and most responders relapse within 2 years (Fenaux Lancet Oncology 2009). Aternative strategies are so required for this population with primary or secondary failure of AZA. Vorinostat is a second generation histone deacetylase inhibitor with significant clinical activity in MDS and leukemia, although the response rate remains low (Garcia-Manero Blood 2008). Synergy of vorinostat with both conventional cytotoxic agents and targeted therapy has been demonstrated in vitro and in vivo (Esteller NEJM 2008). Methods: In this still ongoing study (clinicaltrials.gov NCT00776503), we combined low-dose cytarabine (10-20 mg/m2/day for 14 days sub-cutaneously) and escalating total doses of vorinostat. Two schedules of vorinostat, (400mg/day orally) beginning on day 1 (arm A) or on day 14 (arm B), were tested in 3 groups receiving escalating treatment duration (7days, 10 days and 14 days) following a classical 3+3 phase I schedule. 10 additional pts will be included at the recommended dose level of each cohort (arm A and B). Inclusion criteria were age >18, MDS or AML Results: To date, a total of 34 pts were included and 31 were treated, 21 pts in arm A and 10 pts in arm B. 2 pts died before the beginning of treatment and 1 pt did not fulfill inclusion criteria (no previous AZA). The median age was 71 years (range 46y to 88y), the median number of previous treatments was 2 (1-3) and the median number of cycles of AZA was 10 (range 3–25). All pts had Int-2 (n=15) or High risk MDS (n=16) according to IPSS. A total of 108 cycles of treatment were administered with a median number of 3 cycles/pt and 9 pts had more than 3 cycles. The recommended dose was determined for arm A at 10 days of vorinostat and for arm B at 14 days. The dose limiting toxicities were grade 3 fatigue (n=2), grade 4 bilirubin (n=1) and grade 4 infection (n=2). The most frequent non-limiting toxicities were myelosuppression and GI toxicities. Response was centrally evaluated according to IWG 2006 criteria. The overall response rate was 17% in 29 evaluable pts (2 CRi, 1 HI and 2 marrow CR) with a median duration of response of 3 months (range [2-6+]). There were 2 responders in arm A (1 in 7 days dose level and 1 in 14 days dose level) and 3 responders in arm B (1 in the 7 days dose level and 2 in the 10 days dose level) including the 2 CRi. 14pts remained stable and 10 progressed during treatment. With a median follow up of 9 months, the median overall survival of the cohort is 7.3 months. Conclusions: The phase I results presented here show that 400 mg/day vorinostat can be combined to LDAC and given for 10 days (arm A) to 14 days (armB) with acceptable side effects. It also suggests that the sequential administration might be associated with an increased therapeutic index since longer vorinostat therapy duration could be tolerated with higher response rate (3/10 vs 2/21). Interestingly, responses were observed in pts with poor risk cytogenetics who generally fail LDAC alone (t(3;3), complexe Karyotype). Accrual of additional pts at the recommended dose in each arm is ongoing. Data will be updated accordingly. Disclosures: No relevant conflicts of interest to declare.

Abstract 1880 Background: Red blood cell (RBC) cell transfusion dependency (TD) is an indicator of poor prognosis in IPSS low and int-1 (lower risk) MDS. In addition, median response duration to ESAs is only about 2 years (Park, Blood, 2008). AZA can lead to RBC transfusion independence (RBC-TI) in 30–40% of lower risk MDS (Lyons, JCO, 2009), but it has not been systematically evaluated in ESA-resistant lower risk MDS and it remains unknown if the combination of AZA and ESA would be useful in such patients (pts). Methods: In this randomized phase-II trial (GFMAzaEpo-2008-1 trial, NCT01015352), we compared AZA 75mg/m2/d for 5 days every 28 days for 6 cycles (AZA arm) to the same treatment plus epoetin beta 60000 U/week (AZA+EPO arm) in lower risk MDS. Inclusion criteria were: IPSS low or int-1 MDS resistant to ESA (i.e having received at least 12 weeks of EPO ≥60000 U/w or darbepoetin ≥250 μg/w or having relapsed after response to ESA), and with RBC-TD of at least 4 RBC units in the 8 weeks prior to enrollment. Responders in both arms were eligible for maintenance up to 12 monthly cycles, unless progression or loss of erythroid response occurred. The primary endpoint was major erythroid responses (HI-E major) after 6 courses, according to IWG 2000 criteria. Secondary endpoints included overall IWG 2000 HI-E, including major and minor, after 4 and 6 courses, response duration, IPSS progression, survival and toxicity. An interim analysis was planned after 49 of 98 planned patients were evaluable for response after 6 courses. Results: From Feb 09 to first of Jul 10, 96 pts were included (M/F=2:1); median age 72y (45-85); 3 pts did not receive any study drug and were excluded from the analysis (one consent withdrawal, one pancreatic cancer and one fatal cardiac event); 93 pts are the subject of this analysis (RARS=40, RCMD-RS=16, RCMD=12, RA=5, RAEB1=12, CMML=7, Unclassified=1). IPSS cytogenetics was favorable in 73, intermediate in 18, adverse in 1 (this pt was not excluded from the present analysis) and failed in 1 cases, with no imbalance for all these characteristics between arms. Overall, 68% of the pts were resistant to ESAs and 32% had lost response to ESA (after a median response duration of 32 weeks, range: 4–120). Median RBC-TD was 6 units (range: 4–16) in the 8 weeks prior to enrollment. Fifteen pts were too early for evaluation of response, 78 were evaluable for toxicity and 72 and 52 pts were evaluable for response after 4 and 6 courses, respectively, as 6 and 22 patients went off-study before 4 and 6 courses, respectively, due to toxicity or progression. Although overall HI-E rates were similar in the AZA and AZA+EPO arms, (40 and 36.5 % respectively, P=0.51), there was a trend for more frequent HI-E major after 6 courses (ie the primary endpoint of the study), in the AZA+EPO arm (7/22,32%), compared to the AZA arm (4/30,13%, P=0.17). Furthermore, in responding patients, the proportion of HI-E major was significantly greater in the AZA+EPO arm (87.5%) compared to the AZA arm (30%, P=0.03). Finally, a significant increase in HI-E major between 4 and 6 cycles was noted only in the AZA+EPO arm (P=0.016). Seventeen responding patients entered the maintenance phase. Of the 78 pts evaluable for toxicity, 22 (28%) had to be hospitalized at least once for an anemia-related event (N=6) and/or a clinical infection/febrile neutropenia (N= 16). Interestingly, only 6 pts had to be hospitalized in the AZA+EPO arm, compared to 16 in the AZA arm, (P=0.o4). Conclusions: In this first randomized study comparing AZA and AZA+ EPO in highly transfusion-dependent lower-risk MDS, this planned interim analysis shows a promising trend for more major HI-E in the AZA+EPO arm, suggesting that addition of EPO to AZA increases the frequency of major erythroid responses in those patients, and may also significantly decrease the hospitalization rate due to infectious and non-infectious complications, allowing more patients to receive prolonged treatment with azacitidine. Updated results will be presented at the meeting. Disclosures: Récher: Celgene: Consultancy, Honoraria, Research Funding. Vey:Celgene: Consultancy, Honoraria, Research Funding. Fenaux:Celgene: Consultancy, Honoraria, Research Funding. Gardin:Celgene: Consultancy, Honoraria, Research Funding.