ALBERT

Description: Telomere length (TL) predicts the onset of cellular senescence in vitro but the diagnostic utility of TL measurement in clinical settings is not fully known. We tested the value of TL measurement by flow cytometry and FISH (flowFISH) in patients with mutations in telomerase and telomere maintenance genes. TL had a discrete and reproducible normal range with definable upper and lower boundaries. While TL above the 50th age-adjusted percentile had a 100% negative predictive value for clinically relevant mutations, the lower threshold in mutation carriers was age-dependent, and adult mutation carriers often overlapped with the lowest decile of controls. The extent of telomere shortening correlated with the age at diagnosis as well as the short telomere syndrome phenotype. Extremely short TL caused bone marrow failure and immunodeficiency in children and young adults, while milder defects manifested as pulmonary fibrosis-emphysema in adults. We prospectively examined whether TL altered treatment decisions for newly diagnosed idiopathic bone marrow failure patients and found abnormally short TL enriched for patients with mutations in some inherited bone marrow failure genes, such as RUNX1, in addition to telomerase and telomere maintenance genes. The result was actionable, altering the choice of treatment regimen and/or hematopoietic stem cell donor in one-fourth of the cases (9 of 38, 24%). We conclude that TL measurement by flowFISH, when used for targeted clinical indications and in limited settings, can influence treatment decisions in ways that improve outcome.

Description: With PTCy as GVHD prophylaxis, nonmyeloablative (NMA) HLA- haplo and HLA-matched blood or marrow (BMT) have comparable outcomes. Previous reports showed that discontinuation of immunosuppression (IST) as early as day 60 after infusion of bone marrow (BM) haplo allograft with PTCy is feasible. However, there are certain diseases in which PB may be favored over BM grafts to augment engraftment rates; however, given the higher rates of GVHD with PB, excessive GVHD becomes a concern with early discontinuation of IST. We present a completed, prospective single-center trial of stopping IST at days 90 and 60 after NMA haplo PB. (NCT02556931) From 12/2015-7/2018, 117 evaluable patients (pts) with hematologic malignancies associated with higher rates of graft failure with PTCy (MDS, MPN, overlap syndromes, 2o AML, AML with MRD, MM, and CLL) received NMA PB allografts on trial. Haplo donors were preferred, but in patients lacking suitable haplo relatives, unrelated donors were employed with 6 in each IST cohort. The primary objective was to evaluate the safety and feasibility of reduced‐duration IST (from Day 5 through Day 90 in cohort 1 and through Day 60 in cohort 2.) Transplant inclusion criteria were standard and the conditioning included Cy (14.5 mg/kg IV D -6 and -5), fludarabine (D -6 to -2), TBI (200 cGy D -1) and T-cell replete PB. GVHD prophylaxis consisted of high-dose PTCy (50 mg/kg IV D 3 and 4), mycophenolate mofetil (D 5-35) and IST (tacrolimus/sirolimus) from D 5 forward. Priot to transplantation, pts were assigned to stop IST early if eligible, as defined by having ≥ 5% donor T cells at ~D 56 onward, no relapse, and no grade 2-4 acute or significant chronic GVHD. If ineligible to discontinue IST early, it continued through D 180. Monitoring rules declared reduced IST feasible if ≥ 33% of pts stopped IST early as planned. Safety stopping rules for early IST cessation were based on ≥ 5% graft failure, ≥ 5% NRM, ≥ 50% relapse, and ≥ 10% combined grade 3-4 acute GVHD and severe chronic GVHD, measured from the IST stop date to ~D 180. Historical data from 55 haplo transplants for MDS, CLL, and MPNs at our center using the same regimen and PB grafts informed safety calculations. Of the 117 pts (median age 64 years, range 24-78), the most common diagnoses were MDS (33%), AML (with MRD or arising from antecedent disorder) (31%), MPNs (21%) myeloma (10%), and CLL (6%). By refined Disease Risk Index, 13% were low risk, 69% intermediate and 18% high. Shortened IST was feasible in 75 pts (64%) overall. Ineligibility for shortened IST was due most commonly to GVHD (17 pts), followed by early relapse (11 pts), NRM (7 pts), patient/ physician preference (4 pts) or graft failure (3 pts). Of the 57 patients in the D90 cohort (median follow up 35 mos), 33 (58%) stopped IST early as planned. Of the 60 patients in the D60 cohort (median follow up 20 mos), 42 (70%) stopped IST early as planned. The graft failure rate was 2.6%. NRM was very similar in the two arms, 12% at both 12 and 18 months in the D90 cohort and 10% and 13% at 12 and 18 months in the D60 cohort. Relapse in D90 cohort is 40% at 18 months compared to 33% at 18 months in the D60 cohort. Figure 1 shows cumulative incidence (CI) of acute grade 2-4 and grade 3-4 GVHD. Although the CI of grade 1-2 GVHD may be slightly higher in day 60 cohort, it is only 40% at D180. Severe chronic GVHD was 12% (D90) and 11% (D60) at 540 days. One year OS is 75% and 78% for the D90 and D60 cohorts, respectively. At 12 months PFS is 54% in the D90 group and 67% in the D60. At 12 months, the GRFS is 33% in the D90 group, and 38% in the D60 group. (Figure 2) These data suggest that reduced-duration IST in pts receiving NMA haplo PB with PTCy is feasible and carries an acceptable safety profile. Risks of acute GVHD, chronic GVHD, graft failure and NRM appear similar to historical outcomes with IST until D180 and between the two cohorts. When comparing the D90 and D60 arms, grade 3-4, severe chronic GVHD, GRFS, OS and PFS were similar. Although a larger, prospective trial would be needed to uncover potential small differences in outcomes based on IST duration, these data show that similar to our findings with BM, many PB pts (64% in this trial) can discontinue IST as early as D60 without undue toxicity. The favorable toxicity profile of the PTCy platform, coupled with the feasibility and safety of early IST cessation, provides an ideal setting to incorporate novel post-transplantation approaches for relapse reduction. Figure 1 Disclosures DeZern: Astex Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy. Bolanos-Meade:Incyte Corporation: Other: DSMB fees.

Description: Background: Patients with acute myeloid leukemia (AML) presenting with hyperleukocytosis have frequent complications and early mortality. Pulmonary, central nervous system, and cardiovascular complications are common. Attempts to improve outcomes in the 10% of AML patients arriving with hyperleukocytosis have included leukapheresis. No prospective randomized study has supported the use of leukapheresis, and retrospective reports have revealed persistently poor outcomes as well as emerging concerns of acquired coagulopathy and worsening hypoxemia after leukapheresis. While many centers use a leukapheresis protocol processing two blood volumes, Johns Hopkins protocol routinely processes three-five blood volumes. This study aimed to assess coagulopathy, hypoxemia, and mortality with large volume leukapheresis. Methods: 32 patients with newly diagnosed AML treated with large volume leukapheresis for WBC depletion are included in this report. Demographic, clinical, laboratory, and apheresis-related data were collected. Coagulopathy and hypoxemia-related metrics were evaluated within 6 hours before leukapheresis and within 6 hours of completion of leukapheresis. Descriptive and inferential statistics (chi square and Mann-Whitney U test) were used to compare pre and post-leukapheresis findings and assess clinical outcomes. Results: Twenty-nine of 32 (93.8%) patients presented with symptomatic leukostasis (with pulmonary and/or CNS symptoms in 26/29). Median blood volume processed was 14.8 liters (range 4-23.4L). Mean platelet count decreased from 60x109/L to 37x109/L after leukapheresis (p

Description: Key Points Posttransplantation cyclophosphamide is effective as sole GVHD prophylaxis for myeloablative HLA-matched–related or –unrelated BMT. Despite low chronic GVHD with PTCy, relapse and survival are comparable with outcomes reported using other GVHD prophylactic approaches.

Description: Background: Isocitrate dehydrogenase 2 (IDH2) mutations occur in 5-10% of patients (pts) with myelodysplastic syndrome (MDS) and are frequently associated with intermediate-risk cytogenetics, excess bone marrow blasts, neutropenia and sustained platelets. Enasidenib (ENA) is a selective oral inhibitor of the mutant IDH2 enzyme with single-agent activity in relapsed/refractory acute myeloid leukemia (AML). This study was designed to evaluate the efficacy and tolerability of ENA alone and in combination with azacitidine (AZA) in pts with high-risk IDH2-mutated MDS. Methods: This is a multicenter Phase II trial for pts with IDH2-mutated MDS, AML with 20-30% marrow blasts, or chronic myelomonocytic leukemia. The study includes two cohorts: HMA-naïve pts with high-risk MDS (IPSS int-2 or high-risk; IPSS-R high-risk or very high risk; or high-risk molecular features including TP53, ASXL1, EZH2 and/or RUNX1 mutations) (Arm A) receive AZA + ENA; pts relapsed/refractory with prior HMA therapy (Arm B) receive ENA alone. All pts receive ENA at a dose of 100 mg orally daily, on days 1-28 of each 28-day cycle. In Arm A, ENA is given in combination with AZA 75 mg/m2 IV or SC on days 1-7 of each cycle. The primary efficacy endpoint is overall response rate (ORR), including complete remission (CR), marrow CR (mCR), partial remission (PR) and hematologic improvement (HI) based on the Modified International Working group (IWG) Response Criteria for MDS. The primary safety endpoint is the incidence and severity of adverse events using the Common Toxicity Criteria for Adverse Events v4.0. Results: Using a pre-specified data cutoff of July 1st 2019, 25 pts have been enrolled with a median follow-up of 6.4 months (range, 2.4 - 17.1); 10 HMA-naïve pts (Arm A) and 15 HMA-failure pts (Arm B). The median age was 71 years (range, 46-83) (Table 1). Sixteen pts (64%) had neutropenia (absolute neutrophil count 〈 1.0 x 109/L) and 20 pts (80%) had anemia (hemoglobin 〈 11 g/dL), including 12 (48%) red blood cell (RBC) transfusion-dependent (TD) pts at baseline. Seventeen pts (68%) had high or very high risk IPSS-R. Nineteen pts (76%) had diploid or +8 cytogenetics, and 5 pts (20%) had -7 or complex karyotype. High-risk co-occurring mutations included ASXL1 (46%), RUNX1 (17%), EZH2 (8%) and TP53 (8%). Among 18 evaluable pts (7 too early for response assessment), the ORR was 67% (12/18) (Table 2). In HMA-naïve pts, 6/6 (100%) responded to therapy, including 2 CRs and 4 mCRs (1 with HI for neutrophils [HI-N]). In HMA-failure pts, 6/12 (50%) responded, including 2 CRs, 1 PR, 1 mCR (with HI-N) and 2 with stable disease with HI (1 with HI-N, 1 with HI erythroid). Interestingly, 3 pts who achieved CR also had clearance of the IDH2 mutation (1 in Arm A; 2 in Arm B). Two of 5 pts (40%) and 3/7 pts (43%) with neutropenia at baseline achieved HI-N in Arm A and B, respectively. Median time to first and best response were both 1.3 months (range, 0.9-2.1) in Arm A and 1.8 months (range, 0.9-3.7) and 2.7 months (0.9-4.6), respectively in Arm B. Among evaluable pts with RBC TD at baseline, 0/2 pt and 3/8 (38%) pts achieved transfusion independence, in Arm A and B, respectively. At last follow-up, 16 pts remain on treatment (7 with ongoing response) and 9 pts stopped treatment: 4 due to progression, 1 pt decision, 1 underwent allogeneic transplant and 3 responding pts with mCR died from pneumonia or other infectious complications while on study (Figure 1). Adverse events (AEs) of any grade were reported in 17/25 pts (68%) and grade 3-4 AEs were reported in 11/25 pts (44%). Most AEs were manageable without dose interruption. The most common non-hematological AEs were unconjugated hyperbilirubinemia (39%), nausea (33%), fatigue (33%), pneumonia (22%) and diarrhea (17%). Possible differentiation syndrome (DS) was reported in 3 pts on days 31, 38 and 42 of treatment; 2 pts received dexamethasone with resolution, and 1 pt required hydrea and was ultimately determined to have progression to AML. Four pts developed leukocytosis (white blood cell count of 15.3, 28.3, 35.7, 56.6 x 109/L), with 3 at the time of possible DS and 1 at day 119 considered unrelated to DS. Conclusion: Enasidenib is well tolerated and shows promising efficacy in IDH2-mutated high-risk MDS. The ORR was 67%, including 100% in newly diagnosed pts receiving the combination of azacitidine plus enasidenib and 50% ORR in HMA-failure pts receiving enasidenib alone. The study continues to accrue and updated results will be presented at ASH. Disclosures DeZern: Celgene: Consultancy; Astex Pharmaceuticals, Inc.: Consultancy. Takahashi:Symbio Pharmaceuticals: Consultancy. Konopleva:Astra Zeneca: Research Funding; Calithera: Research Funding; Ablynx: Research Funding; Reata Pharmaceuticals: Equity Ownership, Patents & Royalties; Kisoji: Consultancy, Honoraria; Stemline Therapeutics: Consultancy, Honoraria, Research Funding; Ascentage: Research Funding; Genentech: Honoraria, Research Funding; F. Hoffman La-Roche: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Forty-Seven: Consultancy, Honoraria; Eli Lilly: Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Cellectis: Research Funding; Agios: Research Funding. Loghavi:MDACC: Employment; GLG Consultants: Consultancy; AlphaSights: Consultancy. Alvarado:Jazz Pharmaceuticals: Research Funding; Abbott: Honoraria. Ravandi:Selvita: Research Funding; Xencor: Consultancy, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cyclacel LTD: Research Funding; Macrogenix: Consultancy, Research Funding; Menarini Ricerche: Research Funding. Sasaki:Otsuka: Honoraria; Pfizer: Consultancy. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees. Nazha:Abbvie: Consultancy; Incyte: Speakers Bureau; Daiichi Sankyo: Consultancy; MEI: Other: Data monitoring Committee; Novartis: Speakers Bureau; Jazz Pharmacutical: Research Funding; Tolero, Karyopharma: Honoraria. Roboz:Trovagene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: 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; Actinium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amphivena: Consultancy, Membership on an entity's Board of Directors or advisory committees; Argenx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astex: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celltrion: Consultancy, 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; Eisai: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: 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; MEI Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees; Otsuka: 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; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees. Kantarjian:Immunogen: Research Funding; Cyclacel: Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Research Funding; Jazz Pharma: Research Funding; Astex: Research Funding; Ariad: Research Funding; Amgen: Honoraria, Research Funding; BMS: Research Funding; Takeda: Honoraria; Agios: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Research Funding; Daiichi-Sankyo: Research Funding. Garcia-Manero:Amphivena: Consultancy, Research Funding; Helsinn: Research Funding; Novartis: Research Funding; AbbVie: Research Funding; Celgene: Consultancy, Research Funding; Astex: Consultancy, Research Funding; Onconova: Research Funding; H3 Biomedicine: Research Funding; Merck: Research Funding. DiNardo:medimmune: Honoraria; abbvie: Consultancy, Honoraria; jazz: Honoraria; syros: Honoraria; notable labs: Membership on an entity's Board of Directors or advisory committees; agios: Consultancy, Honoraria; celgene: Consultancy, Honoraria; daiichi sankyo: Honoraria. OffLabel Disclosure: Enasidenib is not approved for the treatment of myelodysplastic syndrome

Description: To develop a prognostic scoring system tailored for therapy-related myelodysplastic syndromes (tMDS), we put together a database containing 1933 patients (pts) with tMDS from Spanish, German, Swiss, Austrian, US, Italian, and Dutch centers diagnosed between 1975-2015. Complete data to calculate the IPSS and IPSS-R were available in 1603 pts. Examining different scoring systems, we found that IPSS and IPSS-R do not risk stratify tMDS as well as they do primary MDS (pMDS), thereby supporting the need for a tMDS-specific score (Kuendgen et al., ASH 2015). The current analysis focuses on cytogenetic information as a potential component of a refined tMDS score, based on this large, unique patient cohort. Of the 1933 pts, 477 had normal karyotype (KT), 197 had missing cytogenetics, while 467 had a karyotype not readily interpretable. Incomplete karyotype descriptions will be reedited for the final evaluation. Of the remaining 1269 pts the most frequent cytogenetic abnormalities (abn) were: -7, del(5q), +mar, +8, del(7q), -5, del(20q), -17, -18, -Y, del(12p), -20, and +1 with 〉30 cases each. Frequencies are shown in Table 1. Some abn were observed mostly or solely within complex KTs, such as monosomies, except -7. Others, like del(20q) or -Y, are mainly seen as single or double abn, while del(5q), -7, or del(7q) are seen in complex as well as non-complex KTs. The cytogenetic profile overlapped with that of pMDS (most frequent abn: del(5q), -7/del(7q), +8, -18/del(18q), del(20q), -5, -Y, -17/del(17p), +21, and inv(3)/t(3q) (Schanz et al, JCO 2011)), with notable differences including overrepresentation of complete monosomies, a higher frequency of -7 or t(11q23), and a more frequent occurrence of cytogenetic subtypes in complex KTs, which was especially evident in del(5q) occurring as a single abn in 16%, compared to 70% within a complex KT. IPSS-R cytogenetic groups were distributed as follows: Very Good (2%), Good (35%), Int (17%), Poor (15%), Very Poor (32%). Regarding the number of abn (including incomplete KT descriptions) roughly 30% had a normal KT, 20% 1, 10% 2, and 40% ≥3 abn, compared to pMDS: 55% normal KT, 29% 1, 10% 2, and 6% ≥3 abn. To be evaluable for prognostic information, abn should occur in a minimum of 10 pts. As a single aberration this was the case for -7, +8, del(5q), del(20q), del(7q), -Y, and t(11;varia) (q23;varia). Of particular interest, there was no apparent prognostic difference between -7 and del(7q); del(5q) as a single abn was associated with a relatively good survival, while the prognosis was poor with the first additional abn; t(11q23) occurred primarily as a single abn and was associated with an extremely poor prognosis, and prognosis of pts with ≥4 abn was dismal independent of composition (Table 1). To develop a more biologically meaningful scoring system containing homogeneous and prognostically stable groups, we will further combine subgroups with different abn leading to the same cytogenetic consequences. For example, deletions, unbalanced translocations, derivative chromosomes, dicentric chromosomes of 17p, and possibly -17 all lead to a loss of genetic material at the short arm of this respective chromosome affecting TP53. Further information might be derived from analyses of the minimal common deleted regions. For some abn, like del(11q), del(3p), and del(9q), this can be refined to one chromosome band only (table 1). Conclusion: Development of a robust scoring system for all subtypes of tMDS is challenging using existing variables. This focused analysis on the cytogenetic score component shows that favorable KTs are evident in a substantial proportion of pts, in contrast to historic data describing unfavorable cytogenetics in the majority of pts. Although complex and monosomal KTs are overrepresented, this suggests the existence of distinct tMDS-subtypes, although some of these cases might not be truly therapy-induced despite a history of cytotoxic treatment. The next steps will be to analyze the prognosis of the different groups, develop a tMDS cytogenetic score, and examine minimal deleted regions to identify candidate genes for development of tMDS, as well as to describe the possible influence of different primary diseases and treatments (radio- vs chemotherapy, different drugs) on induction of cytogenetic subtypes. Our detailed analysis of tMDS cytogenetics should reveal important prognostic information and is likely to help understand mechanisms of MDS development. Disclosures Komrokji: Novartis: Consultancy, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Sole:Celgene: Membership on an entity's Board of Directors or advisory committees. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees. Roboz:Cellectis: Research Funding; Agios, Amgen, Amphivena, Astex, AstraZeneca, Boehringer Ingelheim, Celator, Celgene, Genoptix, Janssen, Juno, MEI Pharma, MedImmune, Novartis, Onconova, Pfizer, Roche/Genentech, Sunesis, Teva: Consultancy. Steensma:Amgen: Consultancy; Genoptix: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Millenium/Takeda: Consultancy; Ariad: Equity Ownership. Schlenk:Pfizer: Honoraria, Research Funding; Amgen: Research Funding. Valent:Amgen: Honoraria; Deciphera Pharmaceuticals: Research Funding; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Ariad: Honoraria, Research Funding; Deciphera Pharmaceuticals: Research Funding. Giagounidis:Celgene Corporation: Consultancy. Giagounidis:Celgene Corporation: Consultancy. Platzbecker:Celgene Corporation: Honoraria, Research Funding; TEVA Pharmaceutical Industries: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen-Cilag: Honoraria, Research Funding; Amgen: Honoraria, Research Funding. Lübbert:Janssen-Cilag: Other: Travel Funding, Research Funding; Celgene: Other: Travel Funding; Ratiopharm: Other: Study drug valproic acid.

Description: Introduction The primary goal for treatment of higher-risk MDS patients (pts) is to improve overall survival (OS) and delay acute myeloid leukemia (AML) evolution. The IWG 2006 response criteria are used in clinical trials and in clinical practice for assessing efficacy of MDS therapies. These criteria were originally proposed by an international group of experts based on available data and consensus. In an ad hoc landmark analysis of the AZA-001 study using the 2006 IWG criteria, pts who achieved hematological improvement (HI), complete response (CR), marrow CR (mCR), or partial response (PR) demonstrated improved OS. The aim of this study is to validate the IWG 2006 response criteria among a large cohort of higher-risk MDS pts. Methods Pts with higher-risk MDS (intermediate-2 (Int-2) or High Risk by International Prognostic Scoring System (IPSS)) who had received treatment and for whom details of response and outcome were available were included from the MDS CRC database. Pts were also classified per IPSS-R. The best response to treatment was categorized per the published IWG 2006 response criteria as CR, PR, mCR, HI, stable disease (SD) or progressive disease (PD). The primary endpoint was OS. Results We identified 646 treated higher-risk MDS pts. Table-1 summarizes baseline characteristics. The first line treatment was hypomethylating agent-based therapy (HMA) in 470 pts (74%). The median duration of follow up was 23.2 months (mo) (95% CI: (19.9, 26.5). Median OS from diagnosis was significantly longer for pts with int-2 IPSS risk disease IPSS (26.2 mo (21.5, 29.7)) compared to those who were High Risk (18.8 mo (15.9, 23.6); (p = 0.026). Median OS from diagnosis also differed by IPSS-R category (p 〈 0.001): for pts with Low risk (n = 6) it was not reached; Intermediate risk it was 41.7 mo (31.8, NR); High Risk it was 28.4 mo (24.1, 33.2); and for pts with Very High it was 16.5 mo (15.3, 19.1). The best IWG 2006 response rate for first line therapy among evaluable pts (n=597) was CR in 93 pts (16%), mCR in 10 (2%), PR in 57(10%), HI in 60 (10%), SD in 233 (39%), and PD in 144 (24%). The median OS based on IWG 2006 best response for first line therapy was 41 mo for CR, 12 mo for mCR, 26 mo for PR, 13 mo for HI, 14 mo for SD and 7 mo for PD. (p

Description: Background: Despite recent advances in the therapeutic armamentarium for AML, outcomes remain dismal for patients (pts) with relapsed/refractory (R/R) AML. Response rates with high dose cytarabine (HiDAC) salvage chemotherapy are approximately 20%. Multiple immune aberrations in AML lead to immune suppression, exhaustion, and senescence. Programmed Death-1 (PD-1), a co-inhibitory receptor (IR) on immune cells, suppresses immune activation and is exploited by leukemic cells to evade immune surveillance. PD-1 and other IRs are up-regulated during disease progression. We hypothesized that pembrolizumab, a monoclonal antibody targeting PD-1, after HiDAC would stimulate a T-cell mediated anti-leukemic immune response. Methods: Eligibility for this study included R/R AML 18-70 years, ECOG PS 0-1 and adequate organ function. Treatment consisted of HiDAC (60 years: 1.5 gm/m2 IV Q12hours days 1-5) followed by pembrolizumab 200 mg IV on day 14. The primary objective of this study was to estimate the overall complete remission (CR + CRi) rate. Secondary objectives included assessment of safety, durability of CR, overall survival (OS) and biomarker correlates of response. Overall responders were eligible to receive maintenance phase pembrolizumab 200 mg IV Q3weeks for up to 2 years until progression. Allogeneic stem cell transplant (alloSCT) was permissible before or after maintenance phase. Results: Thirty-seven pts were enrolled and evaluable (Table 1). Sixteen (43%) pts had refractory disease and 16 (43%) pts had relapsed AML with CR1 duration 3: n=1), AST elevation (32%; Grade 〉3: n=1), fatigue (27%), alkaline phosphatase elevation (24%), and maculopapular rash (19%; Grade 〉3: n=2). Grade 〉3 immune-related adverse events (iRAE) were rare (maculopapular rash: n=2, AST/ALT increase: n=2, right upper quadrant pain with lymphocytic infiltrate in liver: n=1) and self-limiting. Five (14%) pts required steroid administration for grade 2 hyperbilirubinemia (n=1), grade 3 ALT elevation (n=1), grade 3 AST elevation with liver biopsy revealing no evidence of iRAE (n=1), grade 3 bilirubin subsequently deemed to be a delayed hemolytic transfusion reaction (n=1), and grade 3 systolic dysfunction without evidence of myocarditis by endomyocardial biopsy or cardiac MRI (n=1). Sixty-day mortality was 3% (1/37) due to progressive AML. Median time to full neutrophil (〉1x109/L) and platelet (〉100x109/L) recovery was 32 and 31 days, respectively. The overall response (ORR: CR+CRi+PR+MLFS) and composite CR (CR+CRi) rates were 46% [29%,63%] and 38% [22%,55%], respectively, meeting the primary endpoint of the study. Notably, 13/28 (46%) pts receiving HiDAC + pembrolizumab as their first salvage regimen achieved CR/CRi. Two pts refractory to HiDAC (administered within past 6 months) achieved CR including one pt who was refractory to HiDAC salvage 1 month prior to enrollment and ultimately achieved CR without evidence of minimal residual disease. Nine (24%) pts received an alloSCT. There were no instances of Grade 〉3 acute GVHD or veno-occlusive disease post-alloSCT. Nine (24%) pts received maintenance phase pembrolizumab (median # of cycles = 3; range: 1-12) for CR (n=8) or PR (n=1). Seven out of 9 pts relapsed/progressed after maintenance phase. Median follow-up among survivors, and median OS, event-free survival and disease-free survival was 7.8 months, 8.9 months [6.0,13.1], 6.9 months [4.2,11.5], and 5.7 months [1.9,7.3], respectively. Conclusions: Pembrolizumab can be safely administered after HiDAC salvage in R/R AML. Severe iRAE's were uncommon despite administration after cytotoxic chemotherapy. The addition of pembrolizumab to HiDAC led to an encouraging overall CR rate meeting the primary endpoint of the study. Immunogenomic biomarker analyses consisting of B cell receptor amplicon sequencing, RNA-seq of blasts and CD8+ T cells, CD8+ T cell receptor repertoire, whole exome sequencing and flow cytometry analyses are ongoing to determine predictors of response. These results warrant further investigation of IR blockade and other immunomodulatory therapeutic strategies after intensive cytotoxic chemotherapy in AML. Disclosures Zeidner: Takeda: Research Funding; Merck: Research Funding; AsystBio Laboratories: Consultancy; Pfizer: Honoraria; Tolero: Honoraria, Research Funding; Daiichi Sankyo: Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Agios: Honoraria; AbbVie: Honoraria. Vincent:Pharmacyclics: Research Funding; Merck: Research Funding. Foster:Bellicum Pharmaceuticals: Research Funding; Macrogenics: Research Funding; Celgene: Research Funding; Daiichi Sankyo: Consultancy. Coombs:Dedham Group: Consultancy; Covance: Consultancy; Cowen & Co.: Consultancy; Octopharma: Honoraria; H3 Biomedicine: Honoraria; Loxo: Honoraria; Pharmacyclics: Honoraria; Medscape: Honoraria. Webster:Pfizer: Consultancy; Amgen: Consultancy; Genentech: Research Funding. DeZern:Astex Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy. Smith:Jazz: Consultancy; Pfizer: Consultancy; Novartis: Consultancy; Agios: Consultancy. Levis:Amgen: Consultancy, Honoraria; Astellas: Consultancy, Research Funding; FUJIFILM: Consultancy, Research Funding; Menarini: Consultancy, Honoraria; Novartis: Consultancy, Research Funding; Daiichi Sankyo Inc: Consultancy, Honoraria; Agios: Consultancy, Honoraria. Luznik:Merck: Research Funding, Speakers Bureau; Genentech: Research Funding; AbbVie: Consultancy; WindMiL Therapeutics: Patents & Royalties: Patent holder. Serody:Merck: Research Funding; GlaxoSmithKline: Research Funding. Gojo:Amphivena: Research Funding; Amgen Inc: Consultancy, Honoraria, Research Funding; Juno: Research Funding; Merck: Research Funding; Jazz: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria. OffLabel Disclosure: Pembrolizumab is investigational for AML.

Description: Background Patients (pts) with myelodysplastic syndromes (MDS) have heterogeneous outcomes that can range from months for some pts to decades for others. Although several prognostic scoring systems have been developed to risk stratify MDS pts, survival varies even within discrete categories, which may lead to over- or under-treatment. Deficits in discriminatory power likely derive from analytic approaches or lack of incorporation of molecular data. Here, we developed a model that uses a machine learning approach to analyze genomic and clinical data to provide a personalized overall outcome that is patient-specific. Method Clinical and mutational data from MDS pts diagnosed according to 2008 WHO criteria were analyzed. The model was developed in a combined cohort from the Cleveland Clinic and Munich Leukemia Laboratory and validated in a separate cohort from the Moffitt Cancer Center. Next generation targeted deep sequencing of 40 gene mutations commonly found in myeloid malignancies was performed. Pts who underwent hematopoietic cell transplant (HCT) were censored at the time of transplant. A random survival forest (RSF) algorithm was used to build the model, in which clinical and molecular variables are randomly selected for inclusion in determining survival, thereby avoiding the shortcomings of traditional Cox step-wise regression in accounting for variable interactions. Survival prediction is thus specific to each pt's particular clinical and molecular characteristics. The accuracy of the proposed model, compared to other models, was assessed by concordance (c-) index. Results Of 2302 pts, 1471 were included in the training cohort and 831 in the validation cohort. In the training cohort, the median age was 71 years (range, 19-99), 230 pts (16%) progressed to AML, 156 (11%) had secondary/therapy-related MDS, and 130(9%) underwent HCT. Risk stratification by IPSS: 391 (27%) low, 626 (43%) intermediate-1, 280 (19%) intermediate-2, 104 (7%) high, 104 (7%) missing, and by IPSS-R: 749 (51%) very low/ low, 336 (23%) intermediate, 190 (13%) high, 92 (6%) very high, and 104 (7%) missing. Cytogenetic analysis by IPSS-R criteria: 65 (4%) very good, 1060 (72%) good, 193 (13%) intermediate, 60 (4%) poor, and 93 (6%) very poor. The most commonly mutated genes were: SF3B1 (26%), TET2 (25%), ASXL1 (20%), SRSF2 (15%), DNMT3A (12%), STAG2 (8%), RUNX1 (8%), and TP53 (8%). All clinical variables and mutations were included in the RSF algorithm. To identify the most important variables that impacted the outcome and the least number of variables that produced the best prediction, we conducted several feature extraction analyses which identified the following variables that impacted OS (ranked from the most important to the least): cytogenetic risk categories by IPSS-R, platelets, mutation number, hemoglobin, bone marrow blasts %, 2008 WHO diagnosis, WBC, age, ANC, absolute lymphocyte count (ALC), TP53, RUNX1, STAG2, ASXL1, absolute monocyte counts (AMC), SF3B1, SRSF2, RAD21, secondary vs. de novo MDS, NRAS, NPM1, TET2, and EZH2. The clinical and mutational variables can be entered into a web application that can run the trained model and provide OS and AML transformation probabilities at different time points that are specific for a pt, Figure 1. The C-index for the new model was .74 for OS and .81 for AML transformation. The new model outperformed IPSS (c-index .66, .73) and IPSS-R (.67, .73) for OS and AML transformation, respectively. The geno-clinical model outperformed mutations only (c-index .64, .72), mutations + cytogenetics (c-index .68, .74), and mutations + cytogenetics +age (c-index .69, .75) for OS and AML transformation, respectively. Addition of mutational variant allelic frequency did not significantly improve prediction accuracy. When applying the new model to the validation cohort, the c-index for OS and AML transformation were .80, and .78, respectively. Conclusion We built a personalized prediction model based on clinical and genomic data that outperformed IPSS and IPSS-R in predicting OS and AML transformation. The new model gives survival probabilities at different time points that are unique for a given pt. Incorporating clinical and mutational data outperformed a mutations only model even when cytogenetics and age were added. Disclosures Nazha: MEI: Consultancy. Komrokji:Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding. Meggendorfer:MLL Munich Leukemia Laboratory: Employment. Walter:MLL Munich Leukemia Laboratory: Employment. Hutter:MLL Munich Leukemia Laboratory: Employment. Sallman:Celgene: Research Funding, Speakers Bureau. Roboz:Otsuka: Consultancy; Orsenix: Consultancy; Celgene Corporation: Consultancy; Daiichi Sankyo: Consultancy; Pfizer: Consultancy; Cellectis: Research Funding; Argenx: Consultancy; Roche/Genentech: Consultancy; Celltrion: Consultancy; Sandoz: Consultancy; Aphivena Therapeutics: Consultancy; Bayer: Consultancy; Pfizer: Consultancy; Aphivena Therapeutics: Consultancy; Eisai: Consultancy; Sandoz: Consultancy; Eisai: Consultancy; Roche/Genentech: Consultancy; AbbVie: Consultancy; Novartis: Consultancy; Janssen Pharmaceuticals: Consultancy; Bayer: Consultancy; Celltrion: Consultancy; Novartis: Consultancy; Janssen Pharmaceuticals: Consultancy; Astex Pharmaceuticals: Consultancy; Daiichi Sankyo: Consultancy; Celgene Corporation: Consultancy; Jazz Pharmaceuticals: Consultancy; Jazz Pharmaceuticals: Consultancy; Cellectis: Research Funding; Otsuka: Consultancy; Orsenix: Consultancy; Argenx: Consultancy; Astex Pharmaceuticals: Consultancy; AbbVie: Consultancy. List:Celgene: Research Funding. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Maciejewski:Apellis Pharmaceuticals: Consultancy; Ra Pharmaceuticals, Inc: Consultancy; Alexion Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Ra Pharmaceuticals, Inc: Consultancy; Alexion Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Apellis Pharmaceuticals: Consultancy. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Sekeres:Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees.

Description: Introduction: Patients with International Prognostic Scoring System (IPSS) intermediate 1 and 2 (Int) and high risk (HR) MDS benefit from therapy with hypomethylating agents (HMAs) decitabine (DAC) and azacitidine (AZA). Treatment requires 5 or 7 daily parenteral doses every month while the patient is benefitting. An oral HMA taken at home would provide patient convenience, and potentially enhance adherence to treatment particularly for long-term responders. Neither DAC nor AZA is readily bioavailable in oral form due to rapid clearance by cytidine deaminase (CDA) present in the gut and liver. E7727, a novel CDAi, is orally bioavailable with a large safety margin in preclinical models. We report here the final results of a Phase 1 study including an extension arm of a PK-guided first in human dose escalation trial of ASTX727 (the combination of oral DAC and E7727). Methods: Adult patients with Int or HR MDS or Chronic Myelomonocytic Leukemia (CMML) were enrolled in this dose-escalating trial. In addition to assessing the safety of the combination, the primary PK objective was to achieve a mean AUC of DAC following oral ASTX727 comparable to that achieved by IV DAC at the approved daily dose of 20 mg/m2. In the first cycle, each patient received an IV DAC dose of 20 mg/m2 on Day 1 as an internal comparator followed by oral ASTX727 on Days 2-5 escalated by cohort. Subsequent cycles were given with oral ASTX727 on Days 1-5 at the same dose of Cycle 1. Cycles were 28 days in length. Only one component at a time was escalated in each cohort and oral doses were not adjusted for weight or body surface area. Intrapatient dose escalation was permitted. Pharmacodynamics (PD) were evaluated by LINE-1 DNA methylation in peripheral blood. Responses were assessed using the International Working Group (IWG) criteria for response (Cheson et al, 2006). Results: 43 patients were treated in 5 cohorts of 6 patients each plus a 13 patient expansion of cohort 5. The median age was 71.5 years (range 59-86), 30/43 (70%) were male, and median time from diagnosis was 273 days (range 5-3518). Prior therapies had been administered to 22/43 (51%) patients including 20 who had received prior HMA. The AUC for IV DAC 20 mg/m2 in all patients (n=43) had a mean (CV) of 171(37%) ng*hr/mL. The Cmax for IV DAC 20 mg/m2 had a mean (CV) of 179(36%) ng/mL. Doses of each component of ASTX727 were escalated as shown in Table 1. E7727 was escalated first from 40 to 100 mg in cohorts 1 to 3 then kept constant at cohorts 4 to 6. DAC doses were kept constant at 20 mg in cohorts 1 to 3 then escalated to 40 mg at cohort 4 and de-escalated to 30 mg at cohort 5. Dose dependent increases in AUC and Cmax occurred with escalating doses. DAC AUC values after oral ASTX727 approached then exceeded IV at 149% by cohort 4. DAC Cmax values after oral ASTX727 never exceeded IV in any Cohort. Mean % LINE-1 demethylation on cycle 1 Day 8±SE increased with dose escalation reaching 12.8%±3.8 by cohort 4. Lower DAC AUC and Cmax were observed after lowering the oral DAC dose from 40 to 30 mg in cohort 5 as shown in Table 1. One patient in cohort 4 had a dose limiting toxicity of thrombocytopenia and no Grade ≥ 3 drug-related non-hematologic AEs were observed in any patient. The most common ≥ Grade 3 AEs regardless of relationship to the drug were thrombocytopenia (36%), anemia (30%), neutropenia (27%), and febrile neutropenia (21%). No drug-related Grade ≥ 3 gastrointestinal AEs were reported. A median of 5 cycles (range 1-23) were administered, 11 patients remain on therapy, and 14 (32%) have experienced objective clinical responses so far, including 5 Complete Response (CR), 4 marrow CR, and 5 Hematologic Improvement. Of 23 patients initially RBC dependent, 6 (26%), became independent and of 6 who were platelet dependent, 2(33%) became independent. Conclusions: ASTX727 (the combination of E7727 and DAC administered PO concomitantly) achieved the primary PK objective of emulating IV DAC 20 mg/m2 AUC levels with a similar safety profile. Day 8 LINE-1 demethylation in Cohort 4, overall clinical response and transfusion independence rates are consistent with those historically reported following DAC 20 mg/m2 IV for 5 days, even though 47% had received prior HMA therapy. ASTX727 has now proceeded to a randomized phase 2 study comparing IV DAC 20 mg/m2 IV daily for 5 days to oral ASTX727 at the doses of 35 mg DAC and 100 mg E7727 daily for 5 days in Int or HR MDS and CMML patients. Disclosures Odenike: Geron: Research Funding; Suneisis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; CTI/Baxter: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Spectrum: Honoraria, Membership on an entity's Board of Directors or advisory committees; Algeta: Honoraria, Membership on an entity's Board of Directors or advisory committees. Steensma:Amgen: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Ariad: Equity Ownership; Genoptix: Consultancy; Millenium/Takeda: Consultancy. Michaelis:Incyte: Honoraria; Pfizer: Equity Ownership; Celgene: Honoraria, Speakers Bureau. Lowder:Astex Pharmaceuticals, Inc.: Employment. Taverna:Astex Pharmaceuticals: Employment. Oganesian:Astex Pharmaceuticals, Inc.: Employment. Zhang:Astex Pharmaceuticals, Inc.: Employment. Azab:Astex Pharmaceuticals, Inc.: Employment. Savona:Ariad: Membership on an entity's Board of Directors or advisory committees; Amgen Inc.: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Research Funding; Sunesis: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding.