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TO THE EDITOR : There is a critical unmet need for novel treatments for higher-risk myelodysplastic syndromes (MDS), higher-risk chronic myelomonocytic leukemia (CMML), and low-blast (LB) acute myeloid leukemia (AML). For patients ineligible for stem cell transplant (SCT), standard therapy with hypomethylating agents, such as azacitidine and decitabine, is not curative, with most patients relapsing within 2 years. [...]

Correction to: Leukemia 10.1038/s41375-021-01125-4, published online 22 January 2021. In Supplementary Table 2, the n numbers for the response-evaluable patients with higher-risk MDS were swapped for the pevonedistat + azacitidine arm and the azacitidine alone arm. Instead of n = 30 and n = 29 as originally published, these have now been corrected to n = 29 for pevonedistat + azacitidine and n = 30 for azacitidine. No changes were required to the response rate percentages as these were calculated using the correct denominators. The updated files are attached to this correction.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection produces higher morbidity and mortality in hematological malignancies, but evidence in acute myeloid leukemia (AML) is scarce. A multicenter observational study was conducted to determine the clinical outcomes and assess the impact of therapeutic approaches in adult AML patients with SARS-CoV-2 infection in the first wave (March-May 2020). Overall, 108 patients were included: 51.9% with active leukemia and 70.4% under therapeutic schedules for AML. Signs and symptoms of SARS-CoV-2 were present in 96.3% of patients and 82.4% received specific treatment for SARS-CoV-2. The mortality rate was 43.5% and was correlated with age, gender, active leukemia, dyspnea, severe SARS-CoV-2, intensive care measures, neutrophil count, and D-dimer levels. A protective effect was found with azithromycin, lopinavir/ritonavir, and normal liver enzyme levels. During the SARS-CoV-2 first wave, our findings suggested an increased mortality in AML in a short period. SARS-CoV-2 management could be guided by risk factors in AML patients.

SARS-CoV-2 infection can impact survival of patients with acute myeloid leukemia (AML). International experts recommend considering delaying or stopping AML treatment, test patients who need intensive induction and s prioritizing outpatient treatment. However there is little published evidence in AML. Objective To analyze the clinical futures and outcome of SARS-CoV-2 infection in AML patients. Methods and patients Observational multicenter study between March and May 2020; 117 patients reported from 47 Spanish centers, but 13 had no PCR or antibody test documented, finally including 104 patients from 45 hospitals. Results The median age was 68 years, men (56.7% vs 43.3%), and the median time from AML diagnosis to SARS-CoV-2 was 4 months. The mean of comorbidities was 1.2, high blood pressure (40.4%), heart disease (17.3%), diabetes (13.5%), smoking (8.8%), chronic obstructive pulmonary disease or emphysema (7.7%), renal failure (6.7%) and liver dysfunction (1.9%). Cytogenetic risk was low in 16.9%, intermediate in 57.1% and high in 26.0%; 55.7% had active disease, 39.2% complete remission and 5.1% partial response. 29.4% were off-therapy and 70.6% under antileukemic treatment at the time of SARS-CoV-2: induction chemotherapy (25.3%), hypomethylating (19.3%), clinical trial (17.0%), consolidation chemotherapy (14.8%), venetoclax (3.4%), FLT3 inhibitors (3.4%) and/or maintenance (1.1%). Overall 3.7% were newly diagnosed (no prior therapy), 77.8% had received one line of treatment, 14.8% two and 3.7% four. 15.4% had prior allogeneic transplantation. Only 4.0% of the patients were asymptomatic, while the main signs and symptoms were fever (77.8%), pneumonia (75.0%), cough (65.3%), dyspnea (52.0%), diarrhea (20.4%), nausea and/or vomiting (12.2%), rhinorrhea (10.2%) and headache (7.4%). Analytical parameters were: neutrophils 3112 cells/µL (1900-7300), lymphocytes 1090 cells/µL (1000-3000), interleukin 6 118 pg/mL (0-100), ferritin 4505 ng/mL (15-150) and D-dimer 2823 ng/mL (20-500), with liver enzymes altered in 23.9% of cases. 84.2% received specific treatment for coronavirus infection: chloroquine or hydroxychloroquine (82.2%), lopinavir/ritonavir (54.0%), corticosteroids (39.6%), azithromycin (33.0%), tocilizumab (15.8%), plasma convalescent (3.0%), clinical trial medication (3.0%), remdesivir (2.0%) and/or anakinra (1.0%). The course was mild in 14.7% (no hospitalization), moderate in 32.0% and severe in 53.3%. The implementation of intensive measures was assessed in 48.2%(14.9% admitted to the ICU and the remaining 33.3% rejected). The mean time to negativization was 20.5 days, duration of symptoms 17.6 days and the hospital stay 11.1 days. In 48.1% of the cases treatment for AML was maintained, in 26.6% delayed and in 25.3% modified due to coronavirus disease.47.5% died, establishing an association between mortality and age over 60 years (58.3% vs 36.4%, p=0.043), ≥2 lines of treatment (72.7% vs 44.3%, p=0.020), active disease (62.5% vs 29.4%, p=0.002) and pneumonia (61.2% versus 22.7%, p=0.002). Overall 47.5% overcame the infection, and in 5.0% SARS-CoV-2 genetic material was still detected at the time of analysis. A non-significant lower mortality rate was observed among: previous transplantation (45.7% vs 64.3%, p=0.19), neutrophil >1900 cells/µL (41.1% vs 60.0%, p=0.09), lymphocyte >1000 cells/µL (42.9% vs 63.6%, p = 0.09) and hydroxychloroquine/chloroquine plus azithromycin (35.3% vs 60.0%, p=0.10). Conclusions SARS-CoV-2 infection produces high mortality among AML patients. Mortality was correlated with age, active disease and pneumonia. Disclosures Martinez-Lopez: Janssen-cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Research Funding; Novartis: Consultancy; Janssen: Consultancy, Honoraria; Incyte: Consultancy, Research Funding.

Background: The Revised International Prognostic Scoring System (IPSS-R) classifies pts with MDS into risk categories, from very low-risk (vLR) to very high-risk (vHR), which guide treatment (tx) options. Pts with intermediate-risk MDS (IR-MDS) are heterogenous and real-world tx practices and outcomes for these pts are unknown. In Spain, the GESMD is an MDS registry containing more than 16,000 pts registered from 142 study sites which represent the country. We evaluated the real-world tx patterns and survival outcomes of pts with MDS from this registry across IPSS-R risk groups (with a focus on IR-MDS) and explored factors driving tx decisions among pts with IR-MDS. Methods: We analyzed the data collected by the GESMD registry from January 2008 to June 2020. Pts included were adults diagnosed with MDS, with informed consent and ≥6-mo follow up if the pt was alive. Pts who did not have available data on their MDS risk score or their use of hypomethylating agent for MDS were excluded. Prior to inclusion in the registry, a curation process was performed to ensure that each pt had the minimum data set and to avoid duplication and errors. Data queries were responded to by physicians at study sites, and the final data included were reviewed by the investigators. Descriptive statistics were used to summarize demographics, clinical, and tx characteristics overall and by risk groups. Overall survival (OS) was analyzed by risk group and tx type using the Kaplan-Meier estimator and 95% confidence intervals (CIs) were calculated. In pts with IR-MDS, a number of baseline variables (including sex, diagnosis year, transfusion status, risk score, age, and blood and blast counts) were explored to assess their relationship with tx selection between either azacitidine (AZA) or best supportive care (BSC) only (eg, transfusions, growth factors). Results: In total, 4,604 pts were included in this analysis. The median age of enrolled pts was 76 y and 39% were female. Other baseline characteristics are seen in Table 1. Seven hundred sixty-one pts (16.5%) were classified as IR-MDS with similar distribution across IPSS-R risk score subgroups 3.5, 4.0, and 4.5. Txs received by pts in the cohort included AZA, chemotherapy, allogeneic stem cell transplant (alloSCT), BSC, and others (eg, immunosuppressors, androgens; Table 2). The majority of pts with IR-MDS were treated with BSC (61%) and AZA (38%). The median time from diagnosis to start of AZA tx ranged from 1 mo in pts with high-risk (HR) and vHR-MDS to 26 mo in pts with vLR-MDS; pts with IR-MDS started AZA at a median of 3 mo from diagnosis. Survival analysis by IPSS-R group shows that median OS decreased with increased risk score (vLR: 81.3 mo [95% CI, 73.6-89.0], low-risk (LR): 59.0 mo [95% CI, 55.2- 62.8], IR: 29.4 mo [95% CI, 27.0-31.8], HR: 15.2 mo [95% CI, 13.3-17.1], vHR: 9.4 mo [95% CI, 7.7-11.1]). When analyzed by tx type, pts with IR-MDS had longer median OS when treated with AZA or chemotherapy ± alloSCT than with BSC (AZA: 30.1 mo [95% CI, 27.3-32.9], chemotherapy ± alloSCT: 30.1 mo [95% CI, 23.8-36.4], BSC: 24.6 mo [95% CI, 18.5-30.7]; Figure 1). No relevant factors associated with decision to treat pts with IR-MDS with AZA or BSC were identified. Conclusions: This study shows that more than one-third of pts with IR-MDS were treated with AZA shortly after their diagnosis, similar to the HR/vHR group. This cohort represents what we know about MDS and its distribution by risk group, while bringing new information on the use of AZA and its potential value in improving the OS of pts with IR-MDS. It is possible that other factors not included in the analysis (comorbidities, distance to the hospital, social and familial support) might have had an influence on the decision to treat pts with IR-MDS with AZA or offer BSC instead. Selection bias, misclassification, and confounding might occur when using registry data and this may limit the interpretation; however, the study shows important insights into the use of real-world therapies for pts with MDS, especially IR-MDS. The COVID-19 pandemic had an impact on the study, delaying the availability and curation process of data from recent years. Analysis of length of AZA tx in relation to response to tx is ongoing. Figure 1 Figure 1. Disclosures Diez-Campelo: BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Sasse: Novartis: Current Employment, Current holder of stock options in a privately-held company. Wormser: Roche: Current equity holder in publicly-traded company; Novartis: Current Employment, Current equity holder in publicly-traded company. Hernandez Donoso: Novartis: Current Employment, Current holder of stock options in a privately-held company. Colicino: Novartis: Current Employment, Current holder of stock options in a privately-held company. Tormo: Astellas, Novartis, Jazz, Pfizer, Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Sanz: Gilead Sciences: Other: Travel, accommodations, and expenses; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, accommodations, and expenses, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Boehringer Ingelheim: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, accommodations, and expenses; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Helsinn Healthcare: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, accommodations, and expenses, Research Funding. Díaz-Beyá: Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Jerez: Novartis: Consultancy; BMS: Consultancy; GILEAD: Research Funding. Valcárcel: Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sobi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizzer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jansen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene/BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Consultancy, 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. OffLabel Disclosure: Sabatolimab is a novel immuno-myeloid therapy targeting TIM-3 and is under investigation for the treatment of patients with myeloid malignancies

Background: Olutasidenib is a potent, selective, oral, small molecule inhibitor of mutant IDH1 (mIDH1). Olutasidenib has previously shown clinical activity in high-risk AML patients (pts) in a Phase 1 clinical trial (Watts, Blood 2019). The planned interim analysis of an ongoing Phase 2 clinical trial (NCT02719574) in R/R mIDH1 AML pts receiving single-agent olutasidenib 150 mg twice-daily showed an overall response rate (ORR) of 46%, including 33% of pts with CR/CRh (de Botton et al., ASCO/EHA 2021). Here we present data analysis on the mutational characteristics of these pts and the relationship between mutations and clinical response. Methods: The Efficacy Evaluable (EE) set comprised mIDH1R132X pts whose first dose was ≥180 days before the data cut-off (18-JUN-20). The primary endpoint was CR/CRh (complete remission [CR] according to modified IWG 2003 criteria plus CR with partial hematologic recovery [CRh]) response rate. CRh was defined as bone marrow blasts 0.5×10 9/L, and platelet count >50×10 9/L. ORR, a secondary endpoint, comprised CR+CRh+CR with incomplete recovery (CRi) + morphologic leukemia-free state (MLFS) + partial remission (PR). IDH1 mutation subtypes were determined by central analysis, co-mutations were reported by investigators. Baseline characteristics and mutation subtypes were tabulated for the safety population and analysis of response rate by mutation type was performed on the EE set. Results: There were 153 R/R AML pts treated with olutasidenib 150 mg BID (safety set). Of those, 123 were in the efficacy evaluable (EE) set (centrally confirmed IDH1R132 mutation and received first dose at least 180 days prior to the data cut off). For the safety population, cytogenetic risk classification was favorable in 6 (4%) pts, intermediate in 109 (71%) pts, and poor in 25 (16%) pts (unknown, 13 [8%] pts). Eighty-five (56%) pts had IDH1R132C mutation subtype, followed by IDH1R132H (n=35 [23%]), IDH1R132G (n=12 [8%]), IDH1R132S (n=11 [7%]), and IDH1R132L (n=4 [3%]). Ninety-four (61%) pts had 1-3 co-mutations reported by the investigator at baseline, with 4-7 co-mutations in 20 (13%) pts, none in 6 (4%) pts, and not done/unknown in 33 (22%) pts. The most common co-mutations at baseline were: NPM1 (n=40 [26%]), DNMT3A (n=36 [24%]), and ASXL1 (n=21 [14%]. Receptor tyrosine kinase (RTK) mutations were reported in 32 (21%) pts (FLT3, n=18 [12%]; NRAS, n=10 [7%]; KRAS, n=3 [2%]; PTPN11, n=3 [2%]; KIT, n=2 [1%]; NF1, n=2 [1%]), with multiple mutations reported in some pts. For the EE population, responses were achieved in all IDH1R132 mutation subtypes, with ORR and CR/CRh response rates ranging from 27%-54% and 17%-50%, respectively (Table 1). The CR/CRh response rate was lower for pts with IDH1R132H mutations; notably, these pts tended to have a higher percentage of co-mutations, particularly mutations in NPM1 and RTK genes, including FLT3. For EE pts with available co-mutation data (n=96), the mean (SD) number of co-mutations was lower (p Conclusions: Responses were observed across IDH1R132 mutation subtypes, with a relatively lower CR/CRh response rate for pts with a R132H mutation as compared to other subtypes. Pts with a best response of CR/CRh had fewer co-mutations than pts who did not achieve CR/CRh. While the ORR was not significantly reduced for pts with RTK mutations, these pts had a lower CR/CRh response rate compared to pts without any RTK mutations. Additional genetic analyses using ddPCR for IDH1 mutations and NGS on a targeted panel of genes at baseline, best response, and end of study will be presented to further explore primary and secondary resistance mechanisms. Figure 1 Figure 1. Disclosures De Botton: Celgene, Agios, Forma Therapeutics, Astella, Daiichi Sankyo, Syros, Abbvie, Bayer, Seattle Genetics, Janssen: Honoraria; Celgene, Agios, Astellas, Daiichi Sankyo, Syros, Abbvie, Bayer, Janssen, Pierre Fabre, Novartis, Pfizer, Servier: Consultancy; Celgene: Speakers Bureau; Agios, Forma Therapeutics: Research Funding. Yee: Forma Therapeutics: Research Funding; Onconova: Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MedImmune: Research Funding; Jazz: Research Funding; Tolero: Research Funding; AbbVie: Honoraria; F. Hoffmann La Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding; Geron: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; TaiHo: Membership on an entity's Board of Directors or advisory committees; Shattuck Labs: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Paladin: Membership on an entity's Board of Directors or advisory committees; Otsuka: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb/Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Astex: Membership on an entity's Board of Directors or advisory committees, Research Funding. Recher: BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Honoraria; Janssen: Honoraria; Jazz: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MaatPharma: Research Funding; Macrogenics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Wei: Gilead: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; Macrogenics: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: 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, Research Funding, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Montesinos: Forma Therapeutics: Consultancy; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Tolero Pharmaceutical: Consultancy; Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Glycomimetics: Consultancy; Stemline/Menarini: Consultancy; Agios: Consultancy; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astellas Pharma, Inc.: Consultancy, Honoraria, Other: Advisory board, Research Funding, Speakers Bureau. Pigneux: Amgen: Consultancy; Sunesis: Consultancy, Research Funding; BMS Celgene: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Novartis: Consultancy, Research Funding. Braun: Servier: Research Funding; Daiichi-Sankyo, Celgene: Consultancy, Honoraria. Curti: Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees. Esteve: Novartis: Consultancy, Research Funding; Jazz: Consultancy; Pfizer: Consultancy; Astellas: Consultancy; Novartis: Research Funding; Bristol Myers Squibb/Celgene: Consultancy; Abbvie: Consultancy. Grove: Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Jonas: 47, AbbVie, Accelerated Medical Diagnostics, Amgen, AROG, Celgene, Daiichi Sankyo, F. Hoffmann-La Roche, Forma, Genentech/Roche, Gilead, GlycoMimetics, Hanmi, Immune-Onc, Incyte, Jazz, Loxo Oncology, Pfizer, Pharmacyclics, Sigma Tau, Treadwell: Research Funding; AbbVie, BMS, Genentech, GlycoMimetics, Jazz, Pfizer, Takeda, Treadwell: Consultancy; AbbVie: Other: Travel reimbursement. Khwaja: Pfizer, Abbvie: Honoraria; Novartis, Jazz: Speakers Bureau. Blum: Forma Therapeutics, Xencor; Celyad: Research Funding; Amerisource Bergen; Abbvie, Syndax: Honoraria. Hiwase: Novartis: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees. Jurcic: AbbVie, BMS/Celgene, Novartis: Consultancy; AbbVie, Arog Pharmaceuticals, Astellas, BMS/Celgene, Forma Therapeutics, Genentech, Gilead Sciences, PTC Therapeutics, Syros Pharmaceuticals: Research Funding. Watts: Rafael Pharmaceuticals: Consultancy; Genentech: Consultancy; Bristol Myers Squibb: Consultancy; Takeda: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy; Aptevo Therapeutices: Research Funding. Xin: Forma Therapeutics, Inc.: Current Employment. Sedkov: Forma Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Guichard: Forma Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Sweeney: Forma Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Cortes: Sun Pharma: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Bristol Myers Squibb, Daiichi Sankyo, Jazz Pharmaceuticals, Astellas, Novartis, Pfizer, Takeda, BioPath Holdings, Incyte: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Bio-Path Holdings, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Research Funding. Fenaux: Syros Pharmaceuticals: Honoraria; JAZZ: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Celgene/BMS: Honoraria, Research Funding.

It has been recently shown that RAS mutations, which occur in 11-38% of Chronic Myelomonocytic Leukemia (CMML), do not only act via RAS/MEK/ERK signaling, but contribute to the disease through NLRP3 inflammasome activation (Hamarsheh, Nat Comm 2020). Despite a therapeutic approach based on NLRP3/IL1β axis blockade, as bring to a stem cell transplantation (SCT) has been proposed, data on the efficacy of IL1β inhibitors in hematopoietic neoplasms is limited. A 55 year old man with previous autoinflammatory episodes (constrictive pericarditis) was diagnosed on September 2020 of CMML-1 KRAS G12D (Inter-2). Due to worsening (orchiepidedymitis, pneumonitis, cellulitis), and the impossibility of performing an SCT at that time, on December 02 2020 he started anakinra (a IL1β receptor antagonist) with good response. Due to new episodes of autoinflammation, anakinra was discontinued (12 April 2021) with severe clinical worsening (heart failure) and no response to diuretic/corticosteroid. After anakinra was restarted (04 May 2021), a progressive improvement was seen, allowing a successful pericardiectomy before an SCT. We obtained blood samples from this patient (at different times) and plasma and whole blood samples from 11 and 5 other CMML KRAS mut patients, respectively. We also included CMML patients without KRAS mutations (KRAS wt) (n=8), with sepsis (n=5) and healthy individuals (n=9). Plasma levels of 15 inflammatory cytokines associated with NLRP3 inflammasome and NFkB pathways were measured using a customized MILLIPLEX ® kit. The inflammasome marker activation assays were conducted as previously published (Martínez García JJ, Nature Comm 2019). Compared to healthy controls, KRAS wt CMML patients did not show differences in any cytokine tested, except IL6, while KRAS mut patients showed significantly higher levels of IL1α, IL1ra, IL18, IL12p40 (associated with NLRP3 inflammasome), IL6, IL8 (associated with NFkB pathway) and M-CSF (Fig. 1A B). Compared to KRAS wt CMML patients, those with KRAS mut showed higher levels of cytokines associated with both the NLRP3 and NFkB pathways, reaching statistical significance for those related with NLRP3 inflammasome. We also observed changes in inflammasome related cytokines before and after anakinra (Table 1). This cytokine profile in the plasma made us analyze the oligomerization of ASC as a marker of inflammasome activation in monocytes of KRAS mut CMML. We found that in all cases of KRAS mut CMML patients around 30 to 80% of monocytes presented oligomers of ASC measured by the time of flight assay, while in healthy donors and KRAS wt CMML patients, ASC oligomerization occurred upon NLRP3 inflammasome activation with lipopolysaccharide (LPS) + ATP or Pyrin inflammasome activation with LPS and Clostridium difficile B toxin (TcdB) (Fig. 2A). Ex vivo activation of PBMCs from KRAS mut CMML patients showed that despite the high percentage of cells with ASC oligomers, very low levels of IL1b released from these cells, even when NLRP3 was activated with LPS+ATP (Fig. 2B), suggesting that this inflammasome is activated in vivo and could not be further activated ex vivo. As control, Pyrin inflammasome activation in PBMCs from KRAS mut CMML was able to induce IL1b release similarly to healthy controls (Fig. 2B). We then found that anakinra treatment of the KRAS mut CMML patient followed in this study, resulted in a decrease of the percentage of monocytes with basal active inflammasomes (Fig. 2C). A little ex vivo activation of the NLRP3 inflammasome was obtained when cells were treated with LPS+ATP, while Pyrin inflammasome was activated at normal levels after LPS+TcdB treatment (Fig. 2D). The inflammasome basal activation increased in the monocytes of the KRAS mut CMML patient after anakinra withdraw and during clinical deterioration and restarting anakinra (second arrow) decreased the basal percentage of monocytes with ASC oligomers (Fig. 2C). Since ASC oligomers are associated to pyroptosis via caspase 1 activation and gasdermin D processing, we then analyzed pyroptotic markers in the plasma of the patient during the time. ASC was increased when monocytes presented elevated percentage of ASC oligomers (Fig. 2E), suggesting that ASC detection could be a promising biomarker. Overall, we show that, in vivo, the NLRP3 inflammasome activation of KRAS mut CMML patients may revert with IL1β blockers. ASC could identify those candidates to receive this therapy. PI18/00316 Figure 1 Figure 1. Disclosures Jerez: Novartis: Consultancy; BMS: Consultancy; GILEAD: Research Funding. Bellosillo: Thermofisher Scientific: Consultancy, Speakers Bureau; Roche: Research Funding, Speakers Bureau; Qiagen: Consultancy, Speakers Bureau. Hernández-Rivas: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Ferrer Marin: Cty: Research Funding; Incyte: Consultancy, Research Funding; Novartis: Speakers Bureau.

Introduction: Acute Myeloid Leukemia (AML) is an aggressive hematological malignancy. Elderly patients were historically treated with chemotherapy, with ORRs below 30%. Despite treatment improvements with the recent approval of the combination venetoclax plus azacitidine, with 64% of ORR and overall survival of 14.7 months, 25% of patients continue to be refractory and 50% are estimated to relapse. The management of AML, especially in elderly or unfit patients, remains a major challenge. Lysine-specific histone demethylase 1 (LSD1) contributes to the malignant transformation event in AML. Iadademstat (iada) selectively inhibits LSD1 and has shown efficacy in preclinical models, including promoting differentiation in AML. Iada has been administered so far to +100 oncology patients in different clinical trials, showing good safety. With a favorable ADME profile and high bioactivity allowing low dosing regimens, a low DDI risk is anticipated, making iada suitable for different drug combinations and offering additional therapeutic options for patients. This is a 36-month update of the ongoing Phase II ALICE clinical trial of iadademstat plus azacitidine in front-line AML patients. Methods: ALICE (EudraCT 2018-000482-36) is an open-label, single arm, Phase IIa clinical trial to assess the safety, tolerability, dose finding and efficacy of iadademstat in combination with azacitidine for the treatment of adult AML patients. ALICE includes AML patients, who have not received prior treatment other than hydroxyurea and are considered by the investigator as ineligible for intensive chemotherapy or have refused this treatment option. Secondary end points of the study address the anti-leukemic activity of the combination (overall response rate, time to response and duration of response) along with PK/PD measures. Results: Current unaudited data corresponds to 34 patients enrolled, including 22 evaluable patients (with at least 1 bone marrow disease evaluation). Evaluable patients achieved an 73% objective response rate (ORR): 5 complete remissions (CR), 6 CR with incomplete hematological recovery (CRi) and 5 Partial Remissions (PR). The current median Time to Response is 30 days, with some durable responses, extending for more than one year in five patients, with the longest CR up to date above 930 days (still ongoing, with CR and MRD negative). Moreover, 5 patients became transfusion independent and MRD negative. The number of adverse events (AEs) reported is in line with the usual evolution of the disease and with other AML trials. Only 2 AEs (in 2 patients) were deemed as serious reactions, probably related to treatment: one differentiation syndrome (G3) and one intracranial hemorrhage (G5). The most frequent reported adverse reaction was thrombocytopenia, observed in almost half of patients (47%), although 63% of patients had presented with grade ≥3 thrombocytopenia at baseline, making difficult to unequivocally attribute observed cytopenias to treatment. Of note, patients that showed response experienced platelet recovery within the first 3 cycles of treatment. Other than the hematological events, the iada-azacitidine combination appears to be safe and well tolerated. We have not observed other significant non-hematological toxicities or other organ-related toxicities. We expect to achieve full patient recruitment of the ALICE study (36 subjects) in October 2021 and will report updated safety and efficacy results based on an October data cut-off. Conclusions: Data to date indicate that iadademstat has a good safety profile and produces robust, fast and in some cases durable responses. Iadademstat appears to be an active candidate for combination with azacitidine and other agents. Drug-related toxicity appears to be predictable, manageable, and restricted to hematologic events. Considering the novel mechanism of action of iadademstat, a pro-differentiating agent, combination strategies with iadademstat might increase therapeutic options for AML patients in first line treatment, as well as for refractory, intolerant, or relapsed patients. Disclosures Salamero: Pfizer: Consultancy; BMS/Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Somervaille: Novartis: Consultancy, Honoraria. Molero: AbbVie: Honoraria; Jansen: Honoraria; BMS-Celgene: Other: Travel, accommodation expenses. Pérez-Simón: Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Gutierrez: Oryzon Genomics: Current Employment. Buesa: Oryzon Genomics: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Bosch: Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel; TAKEDA: Membership on an entity's Board of Directors or advisory committees, Other: Travel. Montesinos: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Tolero Pharmaceutical: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Stemline/Menarini: Consultancy; Forma Therapeutics: Consultancy; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Glycomimetics: Consultancy; Agios: Consultancy; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astellas Pharma, Inc.: Consultancy, Honoraria, Other: Advisory board, Research Funding, Speakers Bureau.

BACKGROUND: An important progress has been made in understanding the pathophysiology of lower risk MDS in recent years. This progress has been more relevant in some specific subtypes such as del(5q) MDS or MDS with RS (>15% RS in BM or >5% RS + SF3B1 mut). In fact, for the latter subtype, in-depth knowledge of its pathophysiology has led to the recent development of new therapeutic strategies (luspatercept). In this regard, new WHO 2017 classification identify in the lower risk MDS setting 2 categories of patients with different clinical and biological features: those without RS (15% of RS and those with 5% of RS and the presence of SF3B1 mutations. Unfortunately, no clear data regarding disease characteristics and outcome have been analyzed to identify these 3 new subgroups of patients, are those with 5-15RS really like those with >15RS? Therefore, improving knowledge in real life setting of these subgroups of patients will lead to optimize the therapeutic management and the potential development of new therapeutic strategies. AIMS: Our aim was to describe baseline clinical characteristics and their implication in overall survival (OS), progression free survival (PFS) and transfusion free survival (TfFS) among LR-MDS according to the presence of RS. We compare 3 sub-categories within the current WHO classification. METHODS: A retrospective study from the Spanish MDS registry was performed in which patients diagnosed with low-risk MDS (Very low to int risk IPSS-R) were selected. MDS with excess of blasts, del(5q) and/or MDS/MPS were excluded. Finally, 2250 patients were selected which were classified according to the percentage of RS into three groups: 1) patients without RS (defined as less than 5% RS, 15RS) (n=1098). Descriptive analysis and survival estimation was done according to classical definitions (OS, PFS). Transfusion free survival (TfS) was defined from diagnosis to the development of transfusion dependency. RESULTS: In 15RS patients. Ferritin level at diagnosis was also lower for 15RS group and as expected, erythroid cellularity was lower in 15RS. Regarding single or multiline dysplasia, patients with 15RS (47%). Median blast% was higher in patients with Median follow-up was 4.1 years. Interestingly, median OS and range (p25-p75) for 15RS pts (7.66 yr 3.7-12.3) p15RS groups respectively (p=0.002). In this sense, PFS for LR-MDS with 15RS pts (7.01 yr (3.5-12.3) (p15RS (2.4 yr 0.1-7.6) patients (Figure2, p=0.02). SUMMARY: Clinical and biological characteristics of LR-MDS patients according to RS are different and impact on survival, disease evolution and need of treatment. Patients with 5-15RS are in an intermediate situation from 15RS regarding clinical and biological variables and with poorer outcome than >15RS patients. A better understanding of these subgroups could help us to personalize therapeutic options in this heterogeneous subset of patients. Figure 1 Figure 1. Disclosures Sanz: Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, accommodations, and expenses; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, accommodations, and expenses, Speakers Bureau; Gilead Sciences: Other: Travel, accommodations, and expenses; Helsinn Healthcare: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, accommodations, and expenses, Research Funding. Tormo: Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Valcárcel: Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizzer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jansen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene/BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Consultancy, 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; Sobi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Diez-Campelo: BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Introduction Venetoclax, a BCL-2 specific inhibitor, used in combination with azacitidine in patients with newly-diagnosed acute myeloid leukemia (AML) who were ineligible for intensive chemotherapy treatment, has shown high response rate and overall survival compared with azacitidine monotherapy (Di Nardo et al. N Engl J Med 2020; 383:617-629). Moreover, venetoclax in combination with hypomethylating agents or with low-dose cytarabine is being explored in other settings being frequently used in relapsed/refractory (R/R) AML. Aims: We performed a retrospective study of patients diagnosed with R/R AML receiving azacitidine combinations in the Catalan Institute of Oncology (ICO) in order to determine the efficacy and safety of the combination. Methods We analyze 35 patients diagnosed with R/R AML at 4 hospitals belonging to ICO in Spain, treated with venetoclax (400mg/24h; initial daily dose of 100mg with a 3-day ramp-up to target dose of 400mg) in combination with hypomethylating agents (azacitidine 75mg/m 2 or decitabine 20mg/m 2) or low-dose cytarabine (20mg/m 2) from May 2019 to Agost 2021. Event was defined as death, refractoriness to treatment or progressive disease. Results Median age was 72 years (range 44-82). Seventeen (43%) patients had high-risk AML according to ELN 2017. Five (14%) patients received venetoclax in combination with decitabine, 20 (57%) patients with azacitidine, and 10 (29%) patients with low-dose cytarabine. The median number of cycles received was 3 (range 1-25). Early mortality in the first 30 days was 5.7% (2 patients). Overall response rate (ORR) was 58%. Complete remission (CR) rate was 48% and 10% partial remission. Seventeen patients (43%) needed venetoclax dosage adjustments due to hematologic toxicity. Median time to response was 2 months. Four patients (10%) were transitioned to allogeneic stem cell transplantation. The median OS was 9.5 months (95% C.I. 2.6-16.2). Response to treatment after 3-4 cycles, discriminate two groups patients with an OS of 13.57 months in those patients who achieved CR or PR vs 2.1 months in non-responders (p Summary/Conclusions Our study showed that real-world experience of treating patients with R/R AML with venetoclax in combination with hypomethylating agents or low-dose cytarabine is feasible, well tolerated with a rapid and promising response rate and low toxicity profile. Moreover, rapid responses shown with the combination, allow us to identify those patients who may benefit from this approach. Figure 1 Figure 1. Disclosures Sureda: Mundipharma: Consultancy; Bluebird: Membership on an entity's Board of Directors or advisory committees; Roche: Other: Support for attending meetings and/or travel; GSK: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, 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; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau.

Background: Olutasidenib, a potent, selective, oral, small molecule inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1), has been previously shown, as a single agent, to be well tolerated and induce durable complete remissions in a subset of patients (pts) with high-risk relapsed/refractory (R/R) mIDH1 acute myeloid leukemia (AML), with an overall response rate (ORR) of 46% and a CR/CRh rate of 33% (de Botton et al., ASCO/EHA 2021). Azacitidine (AZA) has shown synergistic effects with mIDH1 inhibitors on releasing differentiation block in mIDH leukemia models in vitro. Here, we present results of an ongoing phase 2 trial (NCT02719574) in pts receiving olutasidenib (150 mg twice daily) in combination with AZA (75 mg/m 2) (Olu-AZA). Methods: Pts were enrolled into 1 of 4 Olu-AZA cohorts: (1) pts with R/R AML/MDS who were naïve to prior hypomethylating agent [HMA] and IDH1 inhibitor therapy, (2) pts with R/R AML/MDS who had inadequately responded to or had progressed on prior HMA, (3) pts with R/R AML/MDS who were previously treated with an IDH1 inhibitor as their last therapy prior to enrollment (including pts who received single-agent olutasidenib), and (4) treatment naïve [TN] mIDH1 AML pts who were candidates for AZA first line treatment. The primary endpoint was CR/CRh (complete remission [CR] according to modified IWG 2003 criteria plus CR with partial hematologic recovery [CRh]) response rate. CRh was defined as bone marrow blasts < 5%, absolute neutrophil count > 0.5×10 9/L, and platelet count > 50×10 9/L. ORR, a secondary endpoint, comprised CR+CRh+CR with incomplete recovery (CRi) + morphologic leukemia-free state (MLFS) + partial remission (PR). Duration of treatment (DOT) time to response, and duration of response were estimated using Kaplan-Meier methodology. Due to the low number of MDS pts, response parameters are presented for AML pts only. Results: As of 16-June-2021, a total of 72 pts with AML/MDS (n=63/9) received Olu-AZA (R/R w/o prior HMA/IDH1 therapy, n=20; R/R with prior HMA therapy, n=21; R/R with prior IDH1 therapy, n=20; TN AML, n=11) with a median DOT of 4.7 mo (95% CI: 3.6, 5.7). The median age was 72 y (range: 28‒84) with a median number of prior therapies for R/R pts of 2 (1‒5). At the cut-off, 11 (15%) pts remained on treatment and 61 (85%) had discontinued, most commonly (≥10%) due to: disease progression (32%), transplant (11%), and AEs (10%). For pts with AML, the ORR across Olu-AZA cohorts was 40-68% with a median duration of ORR of 3.7-8.5 mo (not reached [NR] for TN AML) and a median time to first response (PR or better) of 1.6-2.8 mo (Table 1). Notably, the CR/CRh rate ranged from 30-47% including 23-45% of pts in CR, with a median duration of CR/CRh of 4.7-16.0 mo (NR for TN AML) and a median time to CR/CRh of 2.8-4.0 mo. For pts who were transfusion-dependent at baseline, 56-day transfusion independence was achieved by 40-100% of pts for platelets and 25-57% of pts for red blood cells (Table 1). Treatment-emergent adverse events (TEAEs) in ≥25% of pts were nausea (49%), constipation (40%), vomiting (35%), thrombocytopenia (32%), diarrhea (28%), and neutropenia (26%). Grade 3/4 all-causality TEAEs in >10% of pts were neutropenia (26%), thrombocytopenia (25%), anemia (19%), and febrile neutropenia (14%). TEAEs of QTc prolongation (all grades) were reported in 5 (7%) pts with grade 3 events in 2 (3%) pts. All pts were receiving concomitant medications associated with QTc prolongation. No events led to olutasidenib dose reduction or discontinuation. Hepatobiliary TEAEs associated with liver enzyme abnormalities (all grades) were reported in 15 (21%) pts, with grade ≥3 events in 6 (8%) pts. Most pts (n=11) required no dose modification or were successfully rechallenged, 3 pts with grade ≥3 events discontinued treatment, two after recurrence of abnormalities with rechallenge, and one pt died with liver function tests abnormal in the setting of AML progression and sepsis. There were no cases of Hy's law. Investigator-assessed IDH1 differentiation syndrome (any grade) was observed in 6 (8%) pts; most cases resolved with treatment interruption, dexamethasone, and/or supportive treatment; 2 pts had concomitant leukocytosis. Conclusions: Olutasidenib in combination with AZA was well tolerated and induced durable CR/CRh in a subset of high-risk pts with mIDH1 AML. Transfusion independence was achieved in a subset of pts in all cohorts. Additional analyses of safety and efficacy will be presented. Figure 1 Figure 1. Disclosures Cortes: Sun Pharma: Consultancy, Research Funding; Bio-Path Holdings, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Bristol Myers Squibb, Daiichi Sankyo, Jazz Pharmaceuticals, Astellas, Novartis, Pfizer, Takeda, BioPath Holdings, Incyte: Consultancy, Research Funding; Takeda: Consultancy, Research Funding. Esteve: Novartis: Research Funding; Novartis: Consultancy, Research Funding; Astellas: Consultancy; Bristol Myers Squibb/Celgene: Consultancy; Pfizer: Consultancy; Jazz: Consultancy; Abbvie: Consultancy. Bajel: Amgen: Speakers Bureau; Abbvie, Amgen, Novartis, Pfizer: Honoraria. Yee: Astex: Membership on an entity's Board of Directors or advisory committees, Research Funding; Forma Therapeutics: Research Funding; F. Hoffmann La Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Research Funding; Jazz: Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MedImmune: Research Funding; Shattuck Labs: Membership on an entity's Board of Directors or advisory committees; TaiHo: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb/Celgene: Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria; Genentech: Research Funding; Geron: Research Funding; Tolero: Research Funding; Paladin: Membership on an entity's Board of Directors or advisory committees; Otsuka: Membership on an entity's Board of Directors or advisory committees; Onconova: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees. Braun: Servier: Research Funding; Daiichi-Sankyo, Celgene: Consultancy, Honoraria. De Botton: Celgene, Agios, Forma Therapeutics, Astella, Daiichi Sankyo, Syros, Abbvie, Bayer, Seattle Genetics, Janssen: Honoraria; Celgene, Agios, Astellas, Daiichi Sankyo, Syros, Abbvie, Bayer, Janssen, Pierre Fabre, Novartis, Pfizer, Servier: Consultancy; Celgene: Speakers Bureau; Agios, Forma Therapeutics: Research Funding. Recher: Astellas: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Honoraria; Janssen: Honoraria; Jazz: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MaatPharma: Research Funding; Macrogenics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Watts: Takeda: Consultancy, Research Funding; Rafael Pharmaceuticals: Consultancy; Genentech: Consultancy; Bristol Myers Squibb: Consultancy; Jazz Pharmaceuticals: Consultancy; Aptevo Therapeutices: Research Funding. Curti: Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees. Grove: Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Jonas: 47, AbbVie, Accelerated Medical Diagnostics, Amgen, AROG, Celgene, Daiichi Sankyo, F. Hoffmann-La Roche, Forma, Genentech/Roche, Gilead, GlycoMimetics, Hanmi, Immune-Onc, Incyte, Jazz, Loxo Oncology, Pfizer, Pharmacyclics, Sigma Tau, Treadwell: Research Funding; AbbVie, BMS, Genentech, GlycoMimetics, Jazz, Pfizer, Takeda, Treadwell: Consultancy; AbbVie: Other: Travel reimbursement. Montesinos: Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Glycomimetics: Consultancy; Forma Therapeutics: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Tolero Pharmaceutical: Consultancy; Teva: 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, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Stemline/Menarini: Consultancy; Agios: Consultancy; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astellas Pharma, Inc.: Consultancy, Honoraria, Other: Advisory board, Research Funding, Speakers Bureau. Patel: BMS-Celgene, Agios: Membership on an entity's Board of Directors or advisory committees; Aptevo Therapeutics: Research Funding; Peerview: Honoraria. Prebet: BMS: Research Funding; BMS, Curios, Daichi: Consultancy. Wang: Takeda: Consultancy, Honoraria, Other: Advisory board; Novartis: Consultancy, Honoraria, Other: Advisory Board; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Honoraria, Other: Advisory Board; Genentech: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Consultancy, Honoraria, Other: Advisory Board; Mana Therapeutics: Consultancy, Honoraria; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Stemline Therapeutics: Consultancy, Honoraria, Other: Advisory board, Speakers Bureau; Pfizer: Consultancy, Honoraria, Other: Advisory Board, Speakers Bureau; Kite Pharmaceuticals: Consultancy, Honoraria, Other: Advisory Board; DAVA Oncology: Consultancy, Speakers Bureau; Kura Oncology: Consultancy, Honoraria, Other: Advisory board, steering committee, Speakers Bureau; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; Rafael Pharmaceuticals: Other: Data safety monitoring committee; Gilead: Consultancy, Honoraria, Other: Advisory board; Daiichi Sankyo: Consultancy, Honoraria, Other: Advisory board; PTC Therapeutics: Consultancy, Honoraria, Other: Advisory board; Genentech: Consultancy; MacroGenics: Consultancy. Polyanskaya: Forma Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Brevard: Forma Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company, Current holder of stock options in a privately-held company. Sweeney: Forma Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Fenaux: Celgene/BMS: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; JAZZ: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Syros Pharmaceuticals: Honoraria. Wei: Agios: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Macrogenics: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Context: Pevonedistat, the first small-molecule inhibitor of NEDD8-activating enzyme, disrupts proteasomal degradation of select proteins. Setting: Patients with higher-risk MDS/CMML (IPSS-R >3, including intermediate [≥5% blasts], high, or very high risk) or LB-AML naive to hypomethylating agents were randomized 1:1 to receive intravenous pevonedistat 20 mg/m2 on days 1, 3, and 5 plus intravenous/subcutaneous azacitidine 75 mg/m2 on days 1–5, 8, and 9 (n=58), or azacitidine alone (n=62), in 28-day cycles. This abstract focuses on the higher-risk MDS subgroup. Main outcome measures: The study was powered on an endpoint of event-free survival (EFS). Overall survival (OS), overall response rate (ORR) and safety were also assessed. Patient-reported health-related quality of life (HRQoL) was evaluated using the European Organization for Research and Treatment of Cancer (EORTC) QoL Questionnaire-C30. Mutational profiling was performed on screening bone marrow aspirate samples. Results: In the intent-to-treat (ITT) population (n=120), EFS trended longer (median, 21.0 vs 16.6 months; hazard ratio [HR]=0.67; 95% CI, 0.42–1.05; P=.076) and median OS was 21.8 vs 19.0 months (HR=0.80; 95% CI, 0.51–1.26; P=.334) with pevonedistat+azacitidine vs azacitidine. In patients with higher-risk MDS (n=67), EFS was longer (median, 20.2 vs 14.8 months; HR=0.54; 95% CI, 0.29–1.00; P=0.045) and median OS was 23.9 vs 19.1 months (HR=0.70; 95% CI, 0.39–1.27; P=0.240) with pevonedistat+azacitidine vs azacitidine. In response-evaluable patients with higher-risk MDS (n=59), ORR was 79% (pevonedistat+azacitidine) vs 57% (azacitidine); median duration of response was 34.6 vs 13.1 months, respectively. Median azacitidine dose intensity was 98% (both arms) in patients with higher-risk MDS. With pevonedistat+azacitidine vs azacitidine, 94% vs 83% of patients with higher-risk MDS had grade ≥3 adverse events (most common: neutropenia [38% vs 37%], febrile neutropenia [22% vs 31%]). No difference was observed in patient-reported HRQoL between arms, with similar mean scores maintained from study entry to end of treatment. Clinical activity was observed with pevonedistat+azacitidine in patients with higher-risk MDS harboring poor prognostic mutations. Conclusions: Pevonedistat+azacitidine led to longer EFS vs azacitidine in higher-risk MDS, had a comparable safety profile to azacitidine alone, and azacitidine dose intensity was maintained. A randomized phase 3 trial ( NCT03268954 ) is ongoing.

Background: RBC-transfusion dependency (RBC-TD) is associated with a decreased probability of overall survival (OS) and progression free survival (PFS) in patients with myelodysplastic syndromes (MDS) (Malcovati L et al. J Clin Oncol 2007 25:3505) but it is unclear if transfusion dose burden is an independent prognostic factor. The purpose of this study was to assess the impact on lower-risk MDS patients, of RBC-transfusion (RBCT) burden status defined according to revised 2018 IWG criteria (Platzbecker et al; Blood 2018). Material and Methods: According to the R-IPSS selection criteria, we identified in our database 474 lower-risk (R-IPSS risk very low, low and intermediate) MDS patients diagnosed at the Catalan Institute of Oncology of Barcelona (01/1992-07/2018). Transfusion burden history was prospectively registered in our database. Data on the transfusion burden was calculated dividing the cumulative total of units of blood received at the end by the time since the beginning of the interval in which the first transfusion was received. RBCT burden, defined according to 2018 IWG criteria, divided patients into 3 categories (non-transfused [NTD], low transfusion burden [LTB] (3 to 7 units in 16 weeks) and high transfusion burden [HTB] patients (³ 8 units in 16 weeks). In this analysis, patients who had received 1 or 2 RBC units in 16 weeks, where included in the NTD category. Overall survival (OS) and progression free survival (PFS) were measured in years since diagnosis. Results: Median age at diagnosis was 72 years (range 32-101). 332 (70%) patients were male. WHO diagnosis was: 3% CRDU, 7% RA, 42% RCMD, 14% RAEB-1, 4% RAEB-2, 26% CMML, the remaining 4% were MDS-U and isolated 5q deletion. R-IPSS categories were: 178 (38%) very low risk, 219 (46.2%) low risk and 77 (16%) intermediate risk. Median follow up time for survivors was 5.4 years (range 0.25-23.8). 132 (28%) of patients were transfusion dependents (LTB and HTB patients). Mean dose density of packed red blood cells amongst those who were transfusion dependents was 3.2 units per month, with a median of 2.9 units per month (IQR 1.9-4.3). At the time of last follow up, 274 (58%) patients had died and 72 (15%) had progressed to AML. According to 2018 IWG criteria, RBCT burden categories were 342 (72%) NTD, 35 (7%) LTB and 97 (21%) HTB patients. Median OS for RBCT burden categories: NTD (8 years; 95% CI 6.6-9.5), LTB (6.2 years; 95% CI 4.2-8.1) and HTB (3.1 years; 95% CI 2.4-3.8) were significantly different (p Conclusions: Our results confirm in our single-centre experience the negative impact on survival and progression-free survival of RBCT treatment, even at relatively low dose burden. As therapeutical decisions are based on the initial prognostic risk assessment, the inclusion of RBCT burden categories may provide more precise prognostic information with impact on the therapeutic approach. Disclosures Sureda: Novartis: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria; Roche: Honoraria; BMS: Consultancy, Honoraria; Gilead: Consultancy; Janssen: Consultancy, Honoraria.

BACKGROUND: AML risk classification is based on genetics (cytogenetics and molecular features) and more recently also on minimal residual disease (MRD) after chemotherapy. These two aspects allow predicting relapse and supporting or not the most anti-leukemia treatment that remains allogeneic hematopoietic cell transplantation (HCT). We prospectively investigated the combined use of the two predictive markers to allocate post-remission therapy with or without HCT. Objectives of the study were testing: a) if this approach was feasible in a multicenter setting; b) the proportion of patients who were allocated to an allogeneic HCT and finally received the procedure; c) the final distribution into the risk categories and their outcome; d) to analyze the outcome of patients with favorable or intermediate genetics moved to the high risk category because of positive MRD. METHODS: Adult patients with primary AML treated at 15 academic hospitals were included between February 2012 and December 2018. Induction chemotherapy consisted of idarubicin 12 mg/m2 days 1-2-3 and cytarabine 200 mg/m2 days 1 to 7. Consolidation courses were high-dose cytarabine (3 g/m2 or 1.5 g/m2 if ≥60 y/o). The number of consolidation courses was based on genetic risk: 3 in favorable genetics category (FGC) (CBF, NPM1mut/FLT3-ITDwild or ratio0.1%) and/or quantitative PCR of the specific transcripts (RUNX1/RUNX1T1, CBFβ/MYH11 and NPM1). RESULTS: Seven hundred forty-five patients (median age: 55, range18-70 y/o, 51% male) were enrolled. Cytogenetics according the revised MRC classification in 707 informative cases was: CBF AML 12%, intermediate 65% (75% of them normal karyotype), and adverse 23%. FLT3-ITD was detected in 28% of patients with intermediate risk cytogenetics and NPM1 mutation in the same group was present in the 48%. Complete remission (CR) was achieved in 81% (n=603) of patients, 82% and 80% in patients up to and above 60 yrs, respectively. Induction death occurred in 9% of patients, 7% and 11% the two age groups, and 10% of patients had refractory leukemia; 542 (90%) of the 603 CR patients completed the consolidation phase and were risk allocated taking into account genetics and MRD. The remaining CR patients were not allocated because of early relapse (n=22), death in CR (n=5), severe toxicity (n=22) or others (n=12). After risk allocation, 208 (38%) patients were in the genetics-MRD combined favorable group (CFG), 103 (19%) in combined intermediate group (CIG) and 231 (43%) in the combined adverse group (CAG). In the latter, 185 (80%) of patients received an allogeneic HCT in first CR. Fifty-seven patients (11%) moved from the genetically FGC or IGC to the CAG because of high MRD at the end of consolidations. Median follow-up in survivors was 25 months. Overall 4-years survival (OS) of the whole series is 48±2%; event-free survival (EFS) is 77+3% in the CFG group, 45+6% in the CIG and 34+4% in the CAG (p CONCLUSION Risk adapted therapy for primary AML based on genetics and MRD is feasible in a cooperative group setting. The proportion of CR was high (>80%) even in patients older than 60 y/o. MRD assessment at the end of consolidation moved 57 patients with favorable or intermediate genetics to the CAG. Avoiding HCT in first CR in the FGC patients associated to EFS above 75% at 4 years. Allogeneic transplantation feasibility was 80% when this was the intended treatment because of adverse genetics and/or MRD positivity. Risk assessment based on genetics and MRD continues separating three groups of patients with different outcomes. Since relapses remain frequent when adverse AML features are present, further approaches after transplantation, such as targeted agents and immune therapies deserve investigation. Disclosures Sierra: Astellas: Honoraria; Pfizer: Honoraria; Daiichi-Sankyo: Honoraria, Speakers Bureau; Abbvie: Honoraria, Speakers Bureau; Roche: Honoraria; Jazz Pharmaceuticals: Honoraria; Novartis: Honoraria, Research Funding, Speakers Bureau. Salamero:Daichii Sankyo: Honoraria; Pfizer: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Esteve:Jazz Pharmaceuticals: Consultancy; Celgene: Consultancy, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy; Daiichi Sankyo: Consultancy; Roche: Consultancy; Astellas: Consultancy, Speakers Bureau; Pfizer: Consultancy.

Background: Myelodysplastic syndrome (MDS) therapeutic decisions have been traditionally based on the International Prognostic Scoring System (IPSS) (Greenberg et al, Blood 1997) and IPSS-R (Greenberg et al, Blood 2012). Recently, next-generation sequencing genetics has been incorporated into management of MDS, however its use is limited in routine clinical practice. Current prognostic models do not allow the identification of patients with low risk disease (low or intermediate-1 IPSS) and poor prognosis, who could benefit from an early intervention. Garcia-Manero et al (Leukemia 2008) described a specific prognostic scoring system for this subgroup of patients (LR-PSS) based on age ≥60 years, hemoglobin Aim: To analyze the prognostic value of Low Risk Prognostic Scoring System(LR-PSS) in a population of lower risk MDS patients (very low, low and intermediate IPSS-R) analyzing as endpoints overall survival (OS) and leukemia free survival (LFS). Methods: A total of 890 consecutive patients with MDS (01/1992-7/2018) diagnosed at the Catalan Institute of Oncology in Barcelona were included in the study. 539 (60%) had available cytogenetics and therefore, IPSS-R could be assessed. 474 (88%) patients were classified as very low, low and intermediate IPSS-R and were included in the study. Results: 178 (37.6%) patients were classified as very low, 219 (46.2%) low and 77 (16.2%) intermediated IPSS-R risk MDS. Median age at diagnosis was 73 years (range 32-101). 332 (70%) were male. According to the 2008 WHO classification, 2.5% CRDU, 7.4% RA, 42.2% RCMD, 13.7% RAEB‐1, 3.6% RAEB‐2, 26.4% CMML and 4.2% MDS‐U with isolated 5q deletion. At diagnosis, median hemoglobin, platelet and bone marrow blast were 11.6 g/dL (5.5-17.1), 157 x109/L (1-1492) and 2 % (0-17), respectively. 84 (17.7%) patients had unfavorable LR-PSS cytogenetics at diagnosis. Median follow up time for survivors was 5.4 years (range 0.25-23.8). At the time of last follow up, 58.4 % (277) had died and 71 (15%) had progressed to acute myeloid leukemia. When the LR-PSS was applied to the very low, low and intermediate IPSS-R subgroups, three well-differentiated prognostic categories could be identified: 103 patients (21.7%) category 1 (scores 0-2); 330 (69.6%) patients category 2 (scores 3-4) and 41 (8.7%) patients category 3 (scores 5-7) with significant different OS and LFS. Median OS for categories 1, 2 and were 7.1 years (95% CI 4.9-9.2), 5.7 years (95% CI 4.7-6.7) and 2.8 years (95% CI 2.1-3.6), p Summary/Conclusion: When applied to a low risk (very low, low and intermediate) IPSS-R cohort of MDS population, LR-PSS identifies a subgroup of patients with a significantly worse prognosis who could benefit from an early treatment intervention. Disclosures Sureda: Janssen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Gilead: Consultancy; Roche: Honoraria; BMS: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau.

Background Chronic myelomonocytic leukemia (CMML) is an ultrarare stem cell disorder defined by the presence of monocytosis (≥1.0 G/l, ≥10%). Depending on white blood cell (WBC) count, CMML can be divided into a myelodysplastic (MD) (WBC ≤13 G/l) and a myeloproliferative (MP) variant (WBC >13 G/l). Although hypomethylating agents (HMA) have been shown to prolong overall survival (OS) in MDS patients (pts) in prospective, randomized phase III trials, only 6-14 MD-CMML pts were included, and MP-CMML pts were excluded [Silverman 2002; Kantarjian 2006; Fenaux 2009]. EMA approval of azacitidine (AZA) in CMML is thus based on limited experience and restricted to MD-CMML with 10-29% bone marrow blasts (BMB), whereas decitabine (DAC) is not approved for treatment (trt) of CMML in the EU. Smaller analyses and single-arm trials of HMA in CMML exist [Wijermans 2008; Ades 2013; Pleyer 2014; Zeidan 2017; Duchmann 2018; Santini 2018; Coston 2019; Diamantopoulos 2019], but it is still unclear whether HMA provide a benefit in CMML (subgroups) compared with other trts. Aim Evaluate the impact of HMA and hydroxyurea (HU) trt on OS and time to next trt (TTNT). Methods Data were collected from 7 European study groups and 2 US MDS Centers of Excellence; database lock 27.05.19; Assign Data Management and Biostatistics GmbH performed statistical analyses with SAS® 9.3. Of 1657 CMML pts, only those who received trt (n=950), with documented WBC and BMB at 1st line, were included in these analyses (n=845, cohort 1). Pts were stratified according to the EMA approved AZA indication, and inclusion/exclusion criteria of the GFM-DAC-CMML trial assessing DAC +/- HU vs HU (NCT02214407) (diagnosis of CMML, no prior trt [except supportive care, erythropoietin or ≤6 weeks HU], WBC ≥13 G/l and ≥2 of the following: BMB ≥5%, clonal cytogenetic abnormality [other than -Y], hemoglobin 16 G/l, platelet count 2 excluded) (n=486; cohort 2). Results In cohort 1, pts receiving HMA 1st line (n=375) had longer OS (19.8 vs 16.3 months [mo], P=0.0102) and TTNT (13.2 vs 6.7 mo, P=0.0001) than pts treated with non-HMA 1st line (n=470). Survival benefit was longer when comparing pts who received HMA (any time) (AZA [n=442], DAC [n=37], both [n=27]) with those that never received HMA (never HMA; n=339) (23.0 vs 13.0 mo, P The following were significantly less common in pts treated with HMA vs those that were not: diagnosis in the pre-HMA era (8 vs 43%), MP-CMML (48 vs 66%), splenomegaly (27 vs 36%), ECOG≥2 (12 vs 24%), 1 trt line (43 vs 74%). WHO subtype, karyotype, transfusion dependence, LDH, CPSS score, AML transformation and therapy-related CMML were comparable between cohorts. HMA are not approved in the EU for CMML pts with HMA are also unapproved in the EU for MP-CMML pts with ≥10% BMB. In pts with ≥10% BMB (n=257), median OS was longer for MD-CMML vs MP-CMML (19.4 vs 11.2 mo, P=0.0023) and for pts who received HMA vs never HMA (18.3 vs 7.0 mo, P In cohort 2, 1st line trts were HU (n=214), HMA (n=187) and others (n=85). Comparing HMA vs HU 1st line, median OS was 15.6 vs 14.5 mo (P=0.0307) and median TTNT was 8.8 vs 6.5 mo (P=0.0452; Fig G). OS and TTNT were comparable for HU vs other trts (Fig G). Similar observations were made in the larger cohort 1 (Fig H). Conclusions HMA show promising results with survival benefits of +11.4, +10.8 and +9.3 mo in pts with MP-CMML Disclosures Pleyer: Abbvie: Other: Advisory board; Novartis: Other: Advisory board; Inflection Point Biomedical Advisors: Other: Advisory board; Celgene: Other: Advisory board; Agios: Other: Advisory board. Leisch:Novartis: Honoraria, Other: Travel support; Bristol-Myers-Squibb: Honoraria; Celgene: Other: Travel support. Maciejewski:Alexion: Consultancy; Novartis: Consultancy. Kaivers:Jazz Pharmaceuticals: Other: Travel Support. Heibl:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Roche: Honoraria; Daiichi Sankyo: Honoraria; Mundipharma: Honoraria; Celgene: 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; AOP Orphan Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Geissler:Novartis: Honoraria; Roche: Honoraria; Abbvie: Honoraria; AstraZeneca: Honoraria; AOP: Honoraria; Celgene: Honoraria; Pfizer: Honoraria; Amgen: Honoraria; Ratiopharm: Honoraria. Valent:Blueprint: Research Funding; Pfizer: Honoraria; Deciphera: Honoraria, Research Funding; Celgene: Honoraria; Novartis: Consultancy, Honoraria, Research Funding. Medina de Almeida:Novartis: Speakers Bureau; Celgene: Speakers Bureau. Jerez:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria. Germing:Novartis: Honoraria, Research Funding; Amgen: Honoraria; Celgene: Honoraria, Research Funding; Jazz Pharmaceuticals: Honoraria. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees. List:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Symeonidis:Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; MSD: 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, Research Funding; Pfizer: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding; Tekeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Sanz:AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Helsinn Healthcare: Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffman - La Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen - Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Onconova: Membership on an entity's Board of Directors or advisory committees, Research Funding. Greil:Boehringer Ingelheim: Honoraria; Amgen: Consultancy, Honoraria, Other: Travel/accomodation expenses, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: Travel/accomodation expenses, Research Funding; Janssen-Cilag: Honoraria; Mundipharma: Honoraria, Research Funding; Merck: Consultancy, Honoraria, Research Funding; Eisai: Honoraria; Genentech: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Other: Travel/accomodation expenses, Research Funding. OffLabel Disclosure: Azacitidine is not approved for the treatment of MP-CMML or CMML with

Background and Aim: The entity defined by the WHO 2017 classification as myeloid neoplasms with germinal predisposition without preexisting disorder or organ dysfunction is particularly interesting within myelodysplastic syndromes (MDS) for three main reasons: i) in myeloid disease derived from congenital bone marrow failure, therapeutic strategies (e.g., type of conditioning regimen) are defined; it is not the case within the group of young patients with MDS harbouring germinal variants, actually a group candidate for allogeneic transplantation of hematopoietic progenitors, ii) its incidence exceeds the cases secondary to congenital bone marrow failure, and iii) the implications of genetic counseling to patients and relatives are yet to be defined and have not been addressed at the time of diagnosis of MDS. Methods: Whole exome sequencing (WES) was performed on 118 tumour and 73 paired germinal DNA from patients of 16 Spanish Group of MDS (GESMD) centers, diagnosed with de novo MDS between 16-60 years old without previous organ dysfunction. WES libraries were sequenced on a HiSeq4000-NovaSeq6000-Illumina platform, mean number of reads per sample was 144,429,985 with a Phred Quality Score >30 in 94% of bases and a 100x average depth. To identify potential germline-predisposing mutations, a selection tool incorporating 279 genes associated with cause or predisposition to bone marrow failure or cancer was implemented. The analysis of the variants was carried out by means of an in house pipeline: filtering out intronic, synonymous, and those variants with minor allele frequency (MAF) in the general population >1% (ExAC, 1000 Genomes-phase3, TOPmed), and requiring the presence both in tumour and germline DNA with a VAF>37%. In 45 cases without germline material the last requirement was substituted by not being reported as somatic in COSMIC in any cancer. To determine pathogenicity we followed conservative criteria: a CADD Phred score ≥20 and to be considered deleterious in, at least, three out of six used algorithm. Results: In 118 patients, the median age at diagnosis was 47 years with the following WHO 2017 diagnoses: 12% MDS-SLD, 9% MDS-RS, 34% MDS-MLD, 30% MDS-EB, 3% MDS-del(5q), 1%MDS-U, 11% CMML. We found deleterious/pathogenic germ variants in 68 of 118 patients. Strikingly, we found a higher frequency than expected, for this specific subset, in genes not yet considered in the category of myeloid neoplasms with germline predisposition: MSH6 (n=5;4.2%), ATR (n=5;4.2%), ERCC6L2 (n=4;3.4%), PMS2 (n=2; 1.6%), MLH1 (n=3;3.5%), HCLS1 (n=2;1.7%), ITGB3 (n=2;1.7%), LYST (n=4; 3.4%), SAMD9 (n=1;0.8%), MSH2(n=1;0.8%). In genes already considered in the category of myeloid neoplasms with germline predisposition: MPL (n=2;1.7%), DDX41 (n= 2;1.7%), RUNX1 (n=1; 0.8%), ANKRD26 (n=1;0.8%). We also detected 10 cases with deleterious germline variants in genes related to Fanconi anemia (BRIP1, FANCC, FANCD2, FANCG, FANCM, SLX4, XRCC2, RAD51C and BRCA2), 2 cases with a germline variant in a Shwachman-Diamond gene DNAJC21 (1.7%), and 3 cases with germline variant in a telomere biology gene (RTEL1, CTC1 and TERT). We then focused on the characterization of the variants found in 5 genes not considered to date as predisposing to MDS: MSH6, MSH2, MLH1, ATR and PMS2 involved in the instability of microsatellites and whose alteration determines genomic instability and predisposition to a different number of solid tumors. The frequency of patients carrying these variants (13.5%) is much higher than the frequency of DDX41 (1.7%) or CEBPA (not found in our cohort), the two genes currently considered in the category with germline predisposition without a preexisting disorder or organ dysfunction. The sixteen patients carrying these mutations were characterized by a median age of 47 (16-60) years with the following diagnoses, 33% MDS-MLD, 27% MDS-EB1 and 40% CMML, presenting up to 40% with decrease cellularity in the bone marrow. Conclusions: We describe, for the first time, a high frequency of germinal variants in genes that drive genomic instability by modulating the microsatellite pathway, in young adults diagnosed with MDS without previous organ dysfunction. Their frequency and high pathogenicity index warrant functional validation experiments and pose them as potential candidates to be included in future classifications and to be considered in clinical, therapeutic and genetic counseling strategies. Disclosures Díez-Campelo: Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Sanz:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Helsinn Healthcare: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onconova: Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffman - La Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen - Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Jerez:Novartis: Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

BACKGROUND As the result of population aging, hematologists increasingly face the challenge of effectively managing older adults with oncological diseases. The heterogeneity of the aging process means that chronological age does not serve as a pivotal variable on which the clinical or treatment decisions are based. To improve outcomes in older population it is critical to select treatment considering patients' frailty profile and patients' needs to ensure they complete the treatment proposedComprehensive geriatric assessment (CGA) is a gold-standard multidimensional tool to characterize older patients according to their biological frailty profile. CGA identifies patient- and condition-related factors that might be potentially reversible through subsequent clinical interventions Older patient may present some degree of physical decline during the treatment due to variables related to the disease itself and/or to the treatment. This can lead to an accelerated decline from aging, affect their functional independence, their quality of life, and their ability to complete the treatment There is evidence that nutritional support and physical exercise during and after oncological treatments provides benefits in muscular and aerobic condition, quality of life, fatigue and adherence to treatment. But data on hematological patient, usually treated with more intensive schemes associated with a higher incidence of cytopenia and fatigue is scarce ENDPOINT - PRIMARY To determine the impact of an individualized geriatric intervention program of physical exercise and nutritional support on adherence to planned oncological treatment in patients ≥ 70 years with hematological malignancies - SECONDARY Analyze the relation between CGA and aging biomarkersEvaluate adherence to the intervention programDetermine the rate of completion and causes for non-completion of treatmentMeasure at the beginning and end of intervention, and 6 months after treatment completion: The program's effect on physical condition parametersChanges in functional capacity: basic and instrumental activities of daily lifeLevels of fatigueQuality of lifeDetermine the incidence and degree of severity of toxicityDetermine treatment response parameters: time to treatment failure and to progression, disease-free, overall and cancer-specific survival METHODS DESIGN Prospective clinical trial, randomized, parallel and open groupsSETTING Comprehensive cancer centerINCLUSION CRITERIA Histopathological diagnosis of hematological malignancies: multiple myeloma, lymphoproliferative syndromes and myelodisplastic syndromesPatients who meet criteria for medical treatment: chemotherapy, radiotherapy, immunotherapy or targeted therapiesPatients in optimal conditions to perform moderate intensity physical exercise (responsible doctor's judgement)Signature of informed consentEXCLUSION CRITERIA Failure to meet any of the inclusion criteria.INTERVENTION All patients will be assessed through a CGA. The intervention group will received the standard treatment according to the clinical protocol of the institution and will participate in a program of personalized physical exercise and nutritional support. The control group will be treated in a standard manner according to the institution's clinical protocolRANDOMIZATION Subjects will be assigned a 1.1 ratio to one of the groups using a simple randomisation methodMAIN VARIABLE: rate of treatment compliance (relationship between the prescribed dose and the dose administered)SECONDARY VARIABLES: CGA scales, aging biomarkers, nutritional parameters and basal body composition before and after the intervention, quality of life before and after the intervention, toxicity and complications during treatment and response to treatment.STATISTICAL ANALYSIS The comparability of the components of the intervention and control group will be analyzed by Chi square test (qualitative variables) and Student's t test and Wilcoxson test (quantitative variables). The analysis of the intervention will be carried out according to the intention of treatment. The main variable will be analyzed by comparison test of chi-square proportions and confidence intervals will be calculated. The variable will be measured at the end of the intervention, according to the degree of compliance with the nutritional and physical exercise program. Disclosures Domingo-Domenech: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; Seattle Genetics: Research Funding; Bristol-Myers Squibb: Other: Travel expenses; Roche: Other: Travel expenses. González-Barca:Kiowa: Consultancy; Roche: Consultancy, Honoraria; Celgene: Consultancy; Celtrion: Consultancy; AbbVie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Honoraria. Sureda:Roche: Honoraria; BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Gilead: Consultancy; Sanofi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau.

Background: Isocitrate dehydrogenase 1 mutations (IDH1m) occur in 7-14% of AML patients (pts) and approximately 3-4% of MDS pts. Olutasidenib is a highly potent, selective small molecule inhibitor of IDH1m with the therapeutic potential to restore normal cellular differentiation. Azacitidine (AZA) has shown synergistic effects with IDHm inhibitors on releasing differentiation block in IDHm leukemia models in vitro. Methods: The Phase 1 study (NCT02719574) assessed the safety, PK/PD, and clinical activity of olutasidenib in patients with IDH1m AML or MDS. Eligibility criteria included: IDH1m AML or MDS [relapsed/refractory (R/R) or treatment naïve (TN) pts not eligible for or refusing standard therapy], adequate liver and renal function. There were no restrictions for concomitant non-anticancer medications. IDH1m variant allele frequency (VAF) and co-mutations were measured at baseline and during treatment. Available safety data are presented for all pts (AML/MDS); efficacy data are presented for AML pts only. Results: As of April 12, 2019, 32 pts had been treated with single agent (SA) olutasidenib and 46 pts with olutasidenib in combination (COMBO) with AZA; median time on treatment was 4.2 mo for SA (range: 10% of pts, including thrombocytopenia (28% vs 33%), febrile neutropenia (22% vs 28%), anemia (22% vs 20%), pneumonia (16% vs 11%), and leukocytosis (13% vs 15%); COMBO-treated pts had more Gr 3/4 neutropenia (6% vs 28%), fatigue (6% vs 15%), and nausea (0% vs 9%). No QTcF prolongation was reported in SA while 3 (7%) pts treated with COMBO reported prolonged QTcF (1 Gr 3). Ten (13%) pts had differentiation syndrome (4 SA; 6 COMBO), which resolved with temporary interruption of olutasidenib and treatment with dexamethasone, hydroxyurea, and/or supportive care. None led to treatment discontinuation. Nineteen (24%) pts died on treatment or within 28 days of the last dose, no deaths were considered treatment-related. For AML pts, clinical responses occurred in 39% SA and 54% COMBO (CR 15% and 23%, respectively; Table 1). CRs were durable (up to >27 mo); disease control (SD >13 mo) was observed in pts without an IWG-defined response. Of the 59 AML pts (23 SA; 36 COMBO) who were transfusion-dependent at baseline, 26 (11 [48%] SA; 15 [42%] COMBO) and 21 (9 [39%] SA; 12 [33%] COMBO) became transfusion-independent (seen in all response categories) during 28 and 56 days on treatment, respectively. For R/R AML pts, median survival was 8.7 mo for SA and 12.1 mo for COMBO; for TN AML pts, median survival was 8.8 mo for SA (n=4) and not reached for COMBO. For R/R and TN AML patients with available pre- and on-treatment samples, IDH1m clearance or significant reduction (VAF Conclusions: SA and COMBO olutasidenib has shown favorable safety and clinical activity in IDH1m R/R AML with a SA ORR of 41% (95% CI: 21, 64) and a COMBO ORR of 46% (27, 67), and durable disease control. Olutasidenib induces deep responses with IDH1 mutation clearance in a subset of treated pts. Phase 2 investigations of SA and COMBO olutasidenib at the RP2D are ongoing in multiple IDH1m AML populations. Additional combinations are also being explored. Disclosures Watts: Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding. Baer:Forma: Research Funding; Kite: Research Funding; Astellas: Research Funding; Incyte: Research Funding; Takeda: Research Funding; Abbvie: Research Funding; Al Therapeutics: Research Funding. Yang:Agios: Consultancy; AstraZeneca: Research Funding. Prebet:pfizer: Honoraria; novartis: Honoraria; pfizer: Honoraria; Boehringer Ingelheim: Research Funding; novartis: Honoraria. Lee:Helsinn: Consultancy; Jazz Pharmaceuticals, Inc: Consultancy; Roche Molecular Systems: Consultancy; AstraZeneca Pharmaceuticals: Consultancy; Karyopharm Therapeutics: Consultancy; Ai Therapeutics: Research Funding. Schiller:Biomed Valley Discoveries: Research Funding; Bristol Myer Squibb: Research Funding; Astellas: Research Funding; Agios: Research Funding, Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Constellation Pharmaceutical: Research Funding; Daiichi Sankyo: Research Funding; Eli Lilly and Company: Research Funding; FujiFilm: Research Funding; Genzyme: Research Funding; Gilead: Research Funding; Incyte: Research Funding; J&J: Research Funding; Jazz Pharmaceuticals: Honoraria, Research Funding; Karyopharm: Research Funding; Novartis: Research Funding; Onconova: Research Funding; Pfizer Pharmaceuticals: Equity Ownership, Research Funding; Sangamo Therapeutics: Research Funding; Amgen: Other, Research Funding. Dinner:Agios: Consultancy; Pfizer: Consultancy; AstraZeneca: Consultancy. Pigneux:Roche: Honoraria; F. Hoffmann-La Roche Ltd: Honoraria; Pfizer: Honoraria; Abbvie: Honoraria; Jazz: Honoraria; Amgen: Honoraria; Daichi: Honoraria; Astellas: Honoraria; Novartis: Honoraria. Montesinos:Abbvie: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research support, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research support, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: Research support; Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Teva: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau. Wang:Stemline: Other: Advisory role, Speakers Bureau; Daiichi: Other: Advisory role; Amgen: Other: Advisory role; Abbvie: Other: Advisory role; Kite: Other: Advisory role; Jazz: Other: Advisory role; Astellas: Other: Advisory role, Speakers Bureau; celyad: Other: Advisory role; Pfizer: Other: Advisory role, Speakers Bureau; Agios: Other: Advisory role. Seiter:Novartis, Incyte, Celgene, Astellas, Sanofi: Speakers Bureau; Novartis, Astellas,: Consultancy; Novartis, Forma, Sun Pharma, Celgene, Jazz, Roche: Research Funding. Wei:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Macrogenics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra Zeneca: Honoraria, Research Funding; Janssen: Honoraria; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: AHW is a former employee of the Walter and Eliza Hall Institute and receives a fraction of its royalty stream related to venetoclax, Research Funding, Speakers Bureau; Astellas: 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, Research Funding, Speakers Bureau. De Botton:Agios: Consultancy, Research Funding; Celgene: Consultancy, Speakers Bureau; Pierre Fabre: Consultancy; Servier: Consultancy; Pfizer: Consultancy; Novartis: Consultancy; Janssen: Consultancy; FORMA: Consultancy, Research Funding; Syros: Consultancy; Bayer: Consultancy; Abbvie: Consultancy; Daiichi: Consultancy; Astellas: Consultancy. Jonas:AbbVie, Accelerated Medical Diagnostics, AROG, Celgene, Daiichi Sankyo, Esanex, Forma, Genentech/Roche, GlycoMimetics, Incyte, LP Therapeutics, Pharmacyclics: Research Funding; AbbVie, Amgen, GlycoMimetics: Other: Travel expenses; AbbVie, Amgen, Celgene, GlycoMimetics, Jazz, Pharmacyclics, Tolero: Consultancy, Membership on an entity's Board of Directors or advisory committees. Ferrell:Astex Pharmaceuticals: Research Funding; Incyte: Research Funding; Agios: Consultancy; Forma Therapeutics: Research Funding. Dao:Incyte Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Kelly:FORMA Therapeutics: Employment. Sweeney:FORMA Therapeutics: Employment. Forsyth:FORMA Therapeutics: Employment. Guichard:FORMA Therapeutics: Employment. Brevard:FORMA Therapeutics: Employment. Henrick:FORMA Therapeutics: Employment. Mohamed:FORMA Therapeutics: Employment. Cortes:Pfizer: Consultancy, Honoraria, Research Funding; Immunogen: Consultancy, Honoraria, Research Funding; Merus: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Astellas Pharma: Consultancy, Honoraria, Research Funding; BiolineRx: Consultancy; Forma Therapeutics: Consultancy, Honoraria, Research Funding; Biopath Holdings: Consultancy, Honoraria; Jazz Pharmaceuticals: Consultancy, Research Funding; Sun Pharma: Research Funding.

Introduction The association of NPM1mut and FLT3-ITD in de novo acute myeloid leukemia (AML) with intermediate-risk cytogenetics has different prognostic impact depending on the FLT3 allelic burden. Previous studies published by our cooperative group showed that patients with de novo AML of intermediate-risk cytogenetics with NPM1mut and FLT3-ITD low ratio ( We analysed our data to determine whether these findings were confirmed in our cohort, specifically in the low FLT3-ITD ratio patients, since this could have therapeutic implications. Methods and patients A total of 163 patients with de novo AML, intermediate-risk cytogenetics and NPM1mut were analysed (median age 53 years (18-72); male:female 72:91 (0.79)). Eighty patients (49%) harboured an FLT3-ITD, with a high allelic ratio in 42 of 76 patients with available ITD/wt ratio (55%). They were included in the AML-2003 (n=49) and AML-2012 (n=114) CETLAM protocols. Proportion of patients undergoing alloHSCT in CR1 is detailed in table 1. Bone marrow samples from diagnosis were studied for DNMT3A mutations as previously described. The definition of complete remission (CR), overall survival (OS), leukemia-free survival (LFS) and risk of relapse (RR) followed recommended ELN criteria. The Kaplan-Meier method was used to estimate the distribution of LFS and OS, for RR cumulative incidence was used. Results Out of the 163 patients with AML of intermediate risk cytogenetics and NPM1mut, 78 presented DNMT3A mutations (48%). Of these, 62 (79%) presented mutations in codon R882 or corresponded to DNA insertions/deletions while 16 (21%) harboured missense mutations. Presence of DNMT3A mutation did not associate with FLT3-ITD (ITD/85 DNMT3Awt vs ITD/78 DNMT3Amut, p=0.394). In the entire cohort, 5-year OS, LFS and RR were 58±4.5%, 59±4.6% and 27±13.9%. FLT3-ITD ratio confirmed its prognostic impact when analysing FLT3wt (n=83) vs FLT3low (n=34) vs FLT3high (n=42) patients (5-year OS of 68±6% vs 62±8.7% vs 37±8.6%; p=0.002; and 5-year RR of 18±9.4% vs 27±16.1% vs 41±23.2%; p=0.023). On the contrary, DNMT3Amut did not exert any effect on overall outcome (5-yr OS DNMT3Awt vs DNMT3Amut 61±6.2% vs 55±6.2%; p=0.234) When DNTM3A mutational status was considered, the impact of FLT3-ITD on outcome was mitigated in wild-type DNMT3A population. Thus, we found that DNMT3Awt patients presented no statistical differences in OS according to FLT3 mutational status or ratio: FLT3wt (n=46) vs FLT3-ITD (n=39) was 67±8.5% vs 57±8.2%; p=0.122, whereas FLT3wt (n=46) vs FLT3low (n=18) vs. FLT3high (n=19) was 67±8.5% vs. 66±11.5% vs 46±11.8%; p=0.088 (image 1A).This was also seen in relation to LFS and RR according to FLT3 ratio: 5-yr LFS of FLT3wt vs FLT3low vs FLT3high was 72±7.9% vs 61±12.6% vs 51±13.4%; p=0.244 and 5-year RR of the same groups: 19±8.8% vs 26±12.5% vs 27±21.9%; p=0.724 (image 2A). In the DNMT3Amut group, patients with FLT3-ITD (n=41) presented shorter OS than those with FLT3wt (n=37) with an OS of 37±10.7% vs 69±7.8%; p=0.028. When FLT3 ratio was considered, FLT3wt (n=37) vs FLT3low (n=16) vs FLT3high (n=23) showed an OS of 69±7.8% vs. 58±13.2% vs 27±13.1%; p=0.038 (image 1B). Similar results were seen in LFS according to FLT3 ratio (FLT3wt (n=29) vs FLT3low (n=16) vs FLT3high (n=20) 71±8.6% vs 53±12.9% vs 18±13.8%; p=0.012). Finally, we observed significant differences in the 5-year RR when considering DNMT3Amut patients in relation to FLT3 ratio (FLT3wt vs FLT3low vs FLT3high 18±10.6% vs 27±20% vs 54±28.8%; p=0.021)(image 2B). Conclusions In this study, patients with NPM1mut and FLT3-ITDlow presented a similar outcome to patients with NPM1mut and FLT3wt regardless of DNMT3A mutational status. These results support the modification of alloHCST policy in CR1 in CETLAM-2012, which do not consider alloHSCT for patients with FLT3low. On the other hand, concurrence of DNMT3A mutation may have an added negative effect in patients with NPM1mut and FLT3-ITDhigh, which should be further confirmed in larger studies. Disclosures No relevant conflicts of interest to declare.

Introduction Patients diagnosed with AML with NPM1mutation (NPM1mut AML) included in the European LeukemiaNet favorable genetic risk category (ELNfav, i.e., without FLT3-ITD or with a low allelic burden FLT3-ITD comutation [FLT3-ITD/FLT3wt Methods All patients diagnosed with ELNfav NPM1mut AML treated according to CETLAM-12 protocol who achieved CR after 1 or 2 courses of induction chemotherapy were included in the study. Intended post-CR therapy consisted of 3 courses of high-dose cytarabine chemotherapy (HDAC). MRD was assessed in bone marrow samples after each chemotherapy course and thereafter, at regular 3-month interval during 3 years, in reference labs from CETLAM group following standard NPM1-mutation specific RQ-PCR. MF was defined as failure to achieve a molecular response (molCR) after consolidation therapy (i.e., NPM1mut/ABL·100 ratio > 0.05) or MRD reappearance after molCR. All MFs were confirmed in a second sample collected at least 4 weeks apart from previous sample. For patients who present a MF, alloSCT was recommended, without a predefined indication of debulking previous salvage chemotherapy. Results Out of 145 patients with ELNfav NPM1mut AML (75 M/70 F; median age, 56, 18-74), 132 (91%) achieved CR after 1 (n=124) or 2 courses (n=8). After a median follow-up of 25 months, 2-year overall survival (OS), event-free survival (EFS), leukemia-free survival (LFS) of the entire cohort were 79.9% (±3.6), 71.8% (±4) and 79.4% (±3.8), respectively. Among patients with available complete MRD information (n=89), 33 patients developed an hematological and/or molecular failure (Mol/Hem failure), resulting into a Mol/Hem failure-free survival at 2 years of 62% (±5.6%); median time from CR to Mol/Hem failures was 8.2 months (2-43). Fourteen patients presented with an overt hematological relapse (hREL), preceded by a detectable MF in 8. Overall, 14 received salvage therapy in morphological CR, MRD(+) status (MF), and 14 For hREL. Among MF, 5 patients received HDAC-type salvage treatment (followed by alloSCT in 3) and 9 proceeded directly to alloSCT. In 5 additional MF patients with MRD persistence after consolidation, subsequent MRD monitoring showed decreasing MRD levels until complete clearance (n=4) or intermitent detection (n=1) and have not received further therapy. After salvage therapy, 12/14 (86%) patients with MF achieved molCR, and 10/14 (71%) treated for hREL achieved CR2 (MRD negative in 7, 50%), followed by alloSCT in 9. OS after Mol/Hem failure was 64.8% (± 8.4) at 2 years, 88.8 (±7.5%) in patients treated for MRD(+)-status (MF) and 32.1% (±13.6%) in patients treated with overt hREL (p Potential predictive factors of Mol/Hem failure were investigated. Interestingly, a ratio of NPM1mut/ABL*100 ≥1 after induction allowed distinction of two patient subpopulation with strikingly different Mol/Hem failure risk: Mol/Hem failure-free survival at 2 years of 84±6% vs. 33±10% in patients with a lower ( Conclusion Despite a significant proportion of Mol/Hem failures, NPM1mut AML patients allocated in the ELN favorable risk group presented a favorable overall outcome. NPM1mut-based MRD surveillance is able to anticipate most hematological relapses, and a MRD-driven early intervention policy, at time of MF, allowed a successful rescue of a significant proportion of patients. Moreover, an early measure of residual tumor burden, after induction therapy, might identify those patients with a high risk of molecular or hematological subsequent failure, allowing the potential implementation of preemptive intensification strategies. Disclosures No relevant conflicts of interest to declare.

Background: Isocitrate dehydrogenase 1 mutations (IDH1m) occur in 7-14% of AML patients and 3% of MDS patients. Mutated IDH1 metabolizes alpha-ketoglutarate into 2-hydroxyglutarate (2-HG), an oncometabolite that impairs differentiation. FT-2102 is an oral, highly potent, selective small molecule inhibitor of mutated IDH1, with the therapeutic potential to restore normal cellular differentiation. Azacitidine (AZA), a hypomethylating agent (HMA), is a standard of care for MDS and for AML patients unfit for intensive therapy. We present Phase 1 clinical data from the ongoing Phase 1/2 study of FT-2102 in combination with azacitidine (FT-2102+AZA) in patients with IDH1m AML and MDS (CT.gov: NCT02719574). Methods: A Phase 1 study was initiated to evaluate the safety, PK/PD, and antileukemic activity of FT-2102 in patients with IDH1m AML or MDS and included both dose escalation and expansion. FT-2102 was administered daily (150 QD or 150 BID) until disease progression or unacceptable toxicity; AZA was administered at 75 mg/m2 IV or SC daily for 7 days of each 28-day cycle. Eligible patients had IDH1m AML/MDS that was relapsed/refractory (R/R) or treatment-naïve (TN), were eligible for AZA therapy and had adequate liver and renal function. Prior IDH1 inhibitors and hypomethylating agents were allowed, and there were no restrictions for concomitant non-anticancer medications. Investigator-assessed responses were per modified IWG 2003/2006 criteria. Efficacy was assessed at Cycle 2 Day 1 and as clinically indicated thereafter. Adverse events (AEs) were assessed throughout the study per NCI CTCAE version 4.03. Results: At the time of the data cutoff, 07 April 2018, 27 patients had been enrolled and 26 had been treated with FT-2102+AZA, with a median of 3 months on treatment (range: 0.2 to 12 months). Of the 27 enrolled patients, 24 had AML (20 R/R; 4 TN) and 3 patients had MDS (all TN). The median number of prior antileukemia therapies was 3 (range: 0-5) in the AML patients. Doses of FT-2102 were 150 mg QD (n=7) and 150 mg BID (n=20). Thirteen (50%) patients discontinued treatment, with the most common reasons for treatment discontinuation were hematopoietic stem cell transplant (n=4), death (n=2), and progressive disease (n=2). No patients discontinued due to an AE. Severe (≥ Grade 3) AEs occurring in ≥ 5% of patients included febrile neutropenia (27%), anemia, thrombocytopenia, leukocytosis (19% each), fatigue, hypertension, neutropenia (15% each), nausea, pneumonia, hypokalemia (12% each) and abdominal pain (8%). Three patients had differentiation syndrome (IDH-DS), which resolved with FT-2102 temporary interruption, and treatment with dexamethasone, hydroxyurea, and supportive care in all three. Five patients died within 28-days of the last dose of study drug, none of which were considered related to FT-2102+AZA. No DLTs were observed during dose escalation. PK analysis demonstrated no impact of AZA on steady-state exposure of FT-2102. 2-HG levels to normal levels by C2D1. Table 1 shows the Investigator-assessed ORR per IWG. Responses have been seen as early as 1 month on treatment, and stable disease for greater than 6 months; 50% of patients remain on treatment. Conclusions: FT-2102+AZA is well tolerated in AML and MDS, with 150 mg BID selected as the RP2D based on safety, PK and PD (2-HG) response. Clinical activity has been observed, with an ORR of 42%. Durable CRs (>12 months) have been observed. The current data support the continued evaluation of FT-2102 150 mg BID+AZA in the Phase 2 study. Three Phase 2 combination therapy cohorts are currently open for enrollment in patients < 60 years with R/R AML or MDS naïve to HMA and IDH1m inhibitors; R/R AML or MDS with inadequate response/PD on HMA, and R/R AML or MDS who have progressed on a prior IDH1m inhibitor. Updated clinical data will be available at the time of presentation. Disclosures Cortes: Pfizer: Consultancy, Research Funding; Arog: Research Funding; Astellas Pharma: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Novartis: Consultancy, Research Funding. Schiller:Celator/Jazz Pharmaceuticals: Research Funding; Pharmacyclics: Research Funding. Lee:AstraZeneca: Consultancy; Clinipace: Consultancy; Karyopharm Therapeutics Inc: Consultancy; LAM Therapeutics: Research Funding; Amgen: Consultancy. Wang:Amgen: Consultancy; Jazz: Speakers Bureau; Amgen: Consultancy; Jazz: Speakers Bureau; Novartis: Speakers Bureau; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Speakers Bureau; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees. Ferrell:Incyte: Research Funding. Jonas:LP Therapeutics: Research Funding; Genentech/Roche: Research Funding; Incyte: Research Funding; Daiichi Sankyo: Research Funding; Kalobios: Research Funding; Glycomimetics: Research Funding; AbbVie: Consultancy, Research Funding; Forma: Research Funding; Accelerated Medical Diagnostics: Research Funding; Tolero: Consultancy; Esanex: Research Funding; Celgene: Consultancy, Research Funding; Amgen: Consultancy; Pharmacyclics: Research Funding. Wei:Novartis: Honoraria, Other: Advisory committee, Research Funding, Speakers Bureau; Servier: Consultancy, Honoraria, Other: Advisory committee, Research Funding; Pfizer: Honoraria, Other: Advisory committee; Abbvie: Honoraria, Other: Advisory board, Research Funding, Speakers Bureau; Amgen: Honoraria, Other: Advisory committee, Research Funding; Celgene: Honoraria, Other: Advisory committee, Research Funding. Montesinos:Novartis: Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Speakers Bureau. Kelly:Forma Therapeutics Inc.: Employment. Li:Forma Therapeutics Inc.: Employment. Sweeney:Forma Therapeutics Inc.: Employment. Watson:Forma Therapeutics Inc.: Employment. Mohamed:Forma Therapeutics Inc.: Employment.

INTRODUCTION MDS are a heterogeneous group, and it is necessary an adequate prognostic stratification in order to the best management. The new revised international prognostic scoring system (IPSS-R) has improved prognostic ability for survival and AML evolution comparing with the previous prognostic indexes. But, it is not clear the prognosis of patients included in the intermediate group, 20% of MDS, patients with a median OS of 3 years according to Greenberg et al, are they in the high or in the low risk category? The aims of the present study were to describe characteristics of patients included in this intermediate group of the IPSS-R in the Spanish MDS cohort and to identify which factors could have an impact on survival. A new score prognostic system (GESMDi score) in order to a better stratification should be proposed in this subset of patients that will be useful for determine the best therapeutic approach for them. METHODS: All patients were included in the GESMD, diagnosed of Primary MSD and Intermediate IPSS-R. The Statistical analyzes were performed using SPSS version 21, Cox models and Kaplan-Meier curves were used to demonstrate clinical outcomes. Regarding the new score proposed, GESMDi score, modeling of prognostic risk was based on multivariate analysis of survival time. Cox model for survival was built to derive the relative weights within the score. RESULTS: Data from 957 patients of 69 centers of GESMD were evaluated. Their median age was 73.9 years (p25/p75 66-80), 61.6% males (N=590), and median follow-up 21,4 months (p25-p75 de 11-41). Regarding WHO 2001 classification: 31% were RAEB-1, 21% CMML, 18% RCMD, 14% RAEB-2, 3% RCMD-RS, 3.1% RARS, 2.5% RA, 2% 5q-syndrome, 2% AML, 1% unclassified. Median hemoglobin at diagnosis was 9.8 g/dL (p25/p75:8.3-11.6), median bone marrow (BM) blasts 6% (p25/p75:3-8) and median platelet count 99x109/L (p25/p75:66-180). According to IPSS, 5% of patients were classified as low risk, 78% as intermediate-1, 16% as intermediate-2 and 1% as high risk. Cytogenetic were very good in 2% of patients, good in 76%, intermediate in 17%, poor in 5% and in 1% very poor. IPSS-R score classified patients in 3 different groups, with a punctuation of≤ 3.5 (35.6%), >3.5 and ≤ 4 (35.8%) and> 4 and ≤ 4.5 (28.5%). Median OS was 30.1 months, the estimated 1-year and 2-y OS were 79.2% and 57.8%, respectively. In the univariate analysis for OS older age (>74y, p500 ng/ml, p=0.002), and higher IPSS-R score (>3.5 and ≤ 4 and >4 and ≤ 4.5, p=0.023 and p=0.004, figure 1) had a deleterious impact on survival. In the multivariate analysis, only age, Hb level, PB blast, ferritine level and IPSS-R value retained statistical significant impact on OS (table 1a). In the multivariate analysis, Hazard ratio, a new score system (GESMDi score) was established for all patients. Patients with adverse features were added points in order to stratify the risk of death: age500 ng/ml and/or IPSS-R of >3.5 (1 point), table 1a. The GESMDi score was performed in 685 patients with all data available and 7 groups of patients were defined with different median OS (p30 months) and high risk patients ( CONCLUSIONS: GESMDi score, a proposed prognostic score system from patients with intermediate IPSS-R, allow us to establish a better prognosis stratification in this heterogeneous MDS population. Treatment and management should be better established for those patients nowadays according to this novel stratification. Table 1 a) Univariate and multivariate analysis for OS among patients with Intermediate IPSS-R b) OS according to the GESMDi score proposed Table 1. a) Univariate and multivariate analysis for OS among patients with Intermediate IPSS-R b) OS according to the GESMDi score proposed Figure 1 OS according to IPSS-R value in the intermediate group (≤3.5, ≤4 and ≤4.5) Figure 1. OS according to IPSS-R value in the intermediate group (≤3.5, ≤4 and ≤4.5) Figure 2 OS according the GESMDi score proposed in the intermediate IPSS-R group: low and high risk patients (n=685) Figure 2. OS according the GESMDi score proposed in the intermediate IPSS-R group: low and high risk patients (n=685) Disclosures Del Cañizo: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astex: Membership on an entity's Board of Directors or advisory committees; janssen: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Díez Campelo:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astex: Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.