Acute Myeloid Leukemia Myelodysplastic Syndrome Research Articles

A Phase 1 Study of LY3410738, a First-in-Class Covalent Inhibitor of Mutant IDH in Advanced Myeloid Malignancies (Trial in Progress)

A Phase 1 Study of LY3410738, a First-in-Class Covalent Inhibitor of Mutant IDH in Advanced Myeloid Malignancies (Trial in Progress)

Early discontinuation of empirical antibiotic treatment in neutropenic patients with acute myeloid leukaemia and high-risk myelodysplastic syndrome

IntroductionCurrent guidelines advocate empirical antibiotic treatment (EAT) in haematological patients with febrile neutropenia. However, the optimal duration of EAT is unknown. In 2011, we have introduced a protocol, promoting discontinuation of carbapenems as EAT after 3 days in most patients and discouraging the standard use of vancomycin. This study assesses the effect of introducing this protocol on carbapenem and vancomycin use in high-risk haematological patients and its safety.MethodsA retrospective before-after study was performed comparing a cohort from 2007 to 2011 (period I, before restrictive EAT use) with a cohort from 2011 to 2014 (period II, restrictive EAT use). Neutropenic episodes related to chemotherapy or stem cell transplantation (SCT) in patients with acute myeloid leukaemia (AML) or high-risk myelodysplastic syndrome (MDS) were analysed. The primary outcome was the use of carbapenems and vancomycin as EAT during neutropenia, expressed as days of therapy (DOT)/100 neutropenic days and analysed with interrupted time series (ITS). Also the use of other antibiotics was analysed. Safety measurements included 30-day mortality, ICU admittance within 30 days after start of EAT and positive blood cultures with carbapenem-susceptible microorganisms.ResultsThree hundred sixty-two neutropenic episodes with a median duration of 18 days were analysed, involving 201 patients. ITS analysis showed decreased carbapenem use with a step change of − 16.1 DOT/100 neutropenic days (95% CI − 26.77 to − 1.39) and an overall reduction of 21.6% (8.7 DOT/100 neutropenic days). Vancomycin use decreased with a step change of − 13.7 DOT/100 neutropenic days (95% CI − 23.75 to − 3.0) and an overall reduction of 54.7% (14.6 DOT/100 neutropenic days). The use of all antibiotics combined decreased from 155.6 to 138 DOT/100 neutropenic days, a reduction of 11.3%. No deaths directly related to early discontinuation of EAT were identified, also no notable difference in ICU-admission (9/116 in period I, 9/152 in period II) and positive blood cultures (4/116 in period I, 2/152 in period II) was detected.ConclusionThe introduction of a protocol promoting restrictive use of EAT resulted in reduction of carbapenem and vancomycin use and appears to be safe in AML or high-risk MDS patients with febrile neutropenia during chemotherapy or SCT.

Pharmacokinetic (PK)-pharamcodynamic (PD) analysis and receptor occupancy data to support every other week maintenance dosing of magrolimab in combination with azacitidine in MDS/AML patients.

e15098 Background: Magrolimab (Hu5F9-G4) is a monoclonal IgG4 antibody that binds to CD47 receptor and blocks its interaction with SIRPA, thereby enabling tumor cell phagocytosis and activation of an anti-tumor T-cell response. Magrolimab has shown encouraging efficacy and tolerable safety profiles in treatment-naïve myelodysplastic syndromes/acute myeloid leukemia (MDS/AML) patients on an every week (QW) maintenance dosing schedule. Reduced dosing frequency (e.g. every other week – Q2W) is desired to enhance patient convenience and quality of life. Methods: Interim pharmacokinetic (PK) and CD47 receptor occupancy (RO) data from study 5F9005 (Clinical Trial: NCT03248479) were used for this analysis. A previously developed population PK (PopPK) model of magrolimab was verified with observed PK data from study 5F9005. The PK model was linked to peripheral blood and bone marrow blast CD47 RO. The model-predicted RO was validated with observed RO data. Simulations of PK and RO were conducted to justify the proposed reduced dosing frequency of Q2W starting in Cycle 3 onward. Simulations were compared with preliminary observed RO data from the ongoing 5F9005 study after switching to Q2W dosing. Results: The results showed that observed magrolimab PK in study 5F9005 was consistent with model predictions. Model predicted RO was aligned with observed RO data. PK and RO simulations based on the model indicated > 99% RO in peripheral blood and ~90% RO in bone marrow are expected after switching to Q2W dosing regimen from Cycle 3 onward. Preliminary observed RO data confirmed these predictions. Conclusions: Magrolimab PK in AML/MDS is consistent with other patient populations including solid tumors and lymphomas. Model-based simulations and preliminary RO data support Q2W dosing of magrolimab from Cycle 3 onward as optimal RO is expected with the proposed dosing regimen. Clinical trial information: NCT03248479 .

Cyclosporine enhances the sensitivity to lenalidomide in MDS/AML in vitro

Our previous study revealed that expression of G protein-coupled receptor 68 (GPR68) was upregulated in MDSL cells, a cell line representing myelodysplastic syndromes (MDS), in response to lenalidomide (LEN), and mediated a calcium/calpain proapoptotic pathway. Isx, a GPR68 agonist, enhanced the sensitivity to LEN in MDSL cells. The fact that Isx is not a U.S. Food and Drug Administration-approved drug prompts us to look for alternative candidates that could enhance the sensitivity of LEN in MDS as well as other hematologic malignancies, such as acute myeloid leukemia (AML). In the study described here, we found that regulator of calcineurin 1 (RCAN1), an endogenous inhibitor of calcineurin (CaN), was upregulated in MDSL cells in response to LEN, possibly through degradation of IKZF1. Consistently, cyclosporin (Cys), a pharmacological inhibitor of CaN, inhibited the activity of CaN and induced apoptosis in MDSL cells, indicating that CaN provided a prosurvival signal in MDSL cells. In addition, Cys enhanced the cytotoxic effect of LEN in MDS/AML cell lines as well as primary bone marrow cells from MDS patients and AML patient-derived xenograft models. Intriguingly, pretreatment with LEN reversed the suppressive effect of Cys on T-cell activation. Our study suggests a novel mechanism of action of LEN in mediating cytotoxicity in MDS/AML via upregulation of RCAN1, thus inhibiting the CaN prosurvival pathway. Our study also suggests that Cys enhances the sensitivity to LEN in MDS/AML cells without compromising T-cell activation.

European Group for Blood and Marrow Transplantation score correlates with outcomes of older patients undergoing allogeneic hematopoietic stem cell transplantation

Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) are hematological diseases predominantly occurring in older patients. Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the curative therapy for refractory AML or high-risk MDS, old age is often a hurdle to the procedure. We conducted a retrospective study to analyze the prognostic factors predicting outcomes of older patients undergoing allo-HSCT for acute leukemia and MDS. We collected data from patients diagnosed with acute leukemia or MDS, who underwent allo-HSCT at >50 years of age and reviewed clinical characteristics, including age, sex, underlying disease, European Group for Blood and Bone Marrow Transplantation (EBMT) risk score, and presence of acute graft-versus-host disease (aGVHD) or chronic GVHD (cGVHD). The Cox proportional hazard model was adopted to explore the independent prognostic factors for overall survival (OS), progression-free survival (PFS), and non-relapse mortality (NRM). A total of 85 older patients were included, with the median age at allo-HSCT being 55 years. The significant prognostic factors for worse OS or PFS were an EBMT risk score > 3 and grade III-IV aGVHD, while patients with moderate to severe cGVHD would have better OS or PFS. Interestingly, it is not cGVHD but grade III-IV aGVHD that significantly correlated with NRM. This cohort study suggests that an EBMT risk score >3 and grade III-IV aGVHD predict poor outcomes, and careful management of GVHD may allow better survival for older patients undergoing allo-HSCT.

Outpatient intensive induction chemotherapy for acute myeloid leukemia and high-risk myelodysplastic syndrome

AbstractTo improve patient quality of life and reduce health care costs, many conditions formerly thought to require inpatient care are now treated in the outpatient setting. Outpatient induction chemotherapy for acute myeloid leukemia (AML) may confer similar benefits. This possibility prompted a pilot study to explore the safety and feasibility of intensive outpatient initial or salvage induction chemotherapy administration for adults with AML and high-risk myelodysplastic syndrome (MDS). Patients with no significant organ dysfunction and a treatment-related mortality (TRM) score corresponding to a day 28 mortality rate of <5% to 10% were eligible for study. Patients were treated as outpatients with daily evaluation by providers and only admitted to the hospital if mandated by complications. Twenty patients were consented, and 17 were treated. Eight patients received initial induction chemotherapy and 9 received salvage induction chemotherapy. Fourteen patients completed induction chemotherapy administration in the outpatient setting (82.4%; exact 95% confidence interval [CI], 55.8-95.3). Three patients were admitted during the course of chemotherapy administration, 2 for neutropenic fever and 1 for grade 3 mucositis. No patients died within 14 days of the initiation of induction chemotherapy (exact 95% CI, 0-22.9). Results of this pilot study suggest it is feasible to complete outpatient induction chemotherapy in select patients with AML and high-risk MDS. A team including nurses, social workers, medical providers, and pharmacists was key to the successful implementation of outpatient induction.

Transplant Referral Patterns for Patients (Pts) with Newly Diagnosed (ND) Higher-Risk (HR) Myelodysplastic Syndromes (MDS), and European Leukemianet (ELN) 2010 Intermediate-Risk (IR) or Adverse-Risk (AR) Acute Myeloid Leukemia (AML) in the Connect® MDS/AML Registry

Hematopoietic stem cell transplantation (HSCT) is often indicated and formal transplant referral guidelines exist for pts with AML and HR MDS. However, the proportion of transplant-eligible pts not referred is largely unknown. We therefore assessed HSCT referral patterns, including potential barriers to referral, in pts with ND MDS and AML enrolled in the Connect® MDS/AML Disease Registry (NCT01688011), a large, US, multicenter, prospective observational cohort study of pts with ND AML (aged ≥ 55 years) or MDS (aged ≥ 18 years). We evaluated pt data, including transplant referral decisions collected at enrollment and every 3 months, from pts enrolled from Dec 2013 to Jul 2019. HR MDS and AML pts were included; AML pts were grouped by ELN 2010 risk groups into IR AML (Int-1 and Int-2 risk), or AR AML (adverse risk). Differences in transplant referral rates were assessed using a chi-square t-test (significance <i>P</i> < 0.05) in pts with HR MDS. Baseline characteristics of 720 pts with IR AML, AR AML, and HR MDS enrolled at 22 academic (AC) and 119 community/government (CO/GOV) sites are shown (Table). Median time in the Registry was 8.1 (range 0.1–62.9) months. Pts at CO/GOV sites were less likely to be considered for transplant by the treating physician than pts at AC sites (28% vs 43%; <i>P</i> < 0.001); of those considered, there was no difference in the transplant rates between the 2 site types (43% vs 36%; <i>P</i> = 0.290). For 358 pts deemed transplant ineligible, the most common reasons were comorbidities at AC sites and age at CO/GOV sites (Fig. A). Median age of ineligible pts was 77 (range 56–94) years. 7 pts were ineligible because of favorable cytogenetics; however, all had HR MDS, IR AML, or AR AML. In a subset of 262 pts (AC = 79; CO/GOV = 183) identified by investigators as likely potential transplant candidates based on age, comorbidity grade, frailty score, and ECOG PS, pts at AC sites were more likely to be considered for transplant than pts at CO/GOV sites (58% vs 43%; <i>P</i> = 0.020) with age the most common reason for transplant ineligibility (Fig. B) at both sites. Rates of consideration for transplant were lower at CO/GOV sites than AC sites. Among pts identified as potential transplant candidates, rates of consideration were lower at CO/GOV sites suggesting that further education may be needed to ensure referral of all pts who would benefit from transplant.

Serum ferritin and ECOG performance status predict the response and improve the prognostic value of IPSS or IPSS-R in patients with high-risk myelodysplastic syndromes and oligoblastic acute myeloid leukemia treated with 5-azacytidine: a retrospective analysis of the Hellenic national registry of myelodysplastic and hypoplastic syndromes.

Background:5-azacytidine (5-AZA) improves survival of patients with higher-risk myelodysplastic syndromes (MDSs) and oligoblastic acute myeloid leukemia (AML); however, predictive factors for response and outcome have not been consistently studied.Methods:This study of the Hellenic MDS Study Group included 687 consecutive patients with higher-risk MDS and oligoblastic AML treated with 5-AZA.Results:The International Prognostic Scoring System (IPSS) revised version (IPSS-R), Eastern Cooperative Oncology Group Performance Status (ECOG PS) (0 or 1 versus ⩾2) and baseline serum ferritin (SF) levels > 520 ng/ml were shown to independently predict response to 5-AZA. In the survival analysis, the IPSS and IPSS-R risk classification systems along with the ECOG PS and SF levels > 520 ng/ml proved to be independent prognosticators for overall survival (OS), as well as for leukemia-free survival (LFS). Next, we built new multivariate models for OS and LFS, incorporating only ECOG PS and SF levels besides IPSS or IPSS-R risk classification systems. Thereby, the new modified IPSS and IPSS-R risk classification systems (H-PSS, H-PSS-R) could each discriminate a low, an intermediate and a high-risk patient group regarding OS and LFS. The H-PSS and H-PSS-R proved to be better predictors of OS than their previous counterparts as well as the French prognostic score, while the most powerful OS predictor was the new, H-PSS-R system.Conclusions:ECOG PS and SF levels > 520 ng/ml independently predict response to 5-AZA, OS and LFS. Their incorporation in the IPSS and IPSS-R scores enhances these scores’ predictive power in 5-AZA-treated higher-risk MDS and oligoblastic AML patients.

Effect of the Unfolded Protein Response and Oxidative Stress on Mutagenesis of CSF3R a Model of Evolution of Severe Congenital Neutropenia to Myelodysplastic Syndrome/Acute Myeloid Leukemia

Background. Severe congenital neutropenia (SCN) is an inherited bone marrow failure syndrome that can transform to myelodysplastic syndrome/acute myeloid leukemia (MDS/AML). The most common recurrent mutation that causes SCN involve neutrophil elastase (ELANE). Mutations in ELANE result in the unfolded protein response stress. The treatment of choice for SCN is the chronic administration of high-dose granulocyte-colony stimulating factor (G-CSF), which elevates the neutrophil count, helps resolve pre-existing infections, diminishes the number of new infections, and significantly improves the survival and quality of life. G-CSF treatment also leads to enhanced oxidative stress. Long-term survival with G-CSF is frequently associated with development of MDS/AML. Of note, approximately 70% of SCN patients with MDS/AML acquire nonsense mutations in the region of CSF3R that encodes the cytoplasmic domain. These somatic CSF3R mutations are characterized by a truncation variant found in the cytoplasmic domain of the CSF3R and are associated with a hyper-proliferative/impaired differentiative phenotype that might contribute to the MDS/AML transformation. We hypothesize that the terminal exon of CSF3R constitutes a hotspot vulnerable to mutations resulting from excessive oxidative stress or endoplasmic reticulum (ER) stress. Results. Murine factor-dependent Ba/F3 cells were used to measure the effect of induced oxidative or ER stress on the mutation rate involving the hypothesized hotspot of the exogenous human CSF3R, the corresponding region in the endogenous Csf3r, and Runx1 (a transcription factor involved in leukemogenesis). Ba/F3 cells transduced with the cDNA for the hypothesized hotspot of CSF3R (partial C-terminal) fused in-frame with m-NeonGreen, a yellow-green fluorescent protein, were subjected to stress-inducing treatment for 30 days (~51 doubling times). The amplicon-based targeted deep-sequencing data for days 15 and 30 samples showed increased mutagenesis of the coding nucleotide sequences for CSF3R, Csf3r, and Runx1. There was no correlation between the stress-inducing chemical treatments and overall level of mutagenesis in Ba/F3 cells. Interestingly, the GC-rich partial CSF3R region was less mutated as compared to the mNeonGreen region, having much lower GC content. However, analysis of our data, including the site-frequency spectra, indicated effects that may be due to clonal selection, specifically at the Csf3r gene. Conclusion. Our data suggested that oxidative or ER stress induction did not promote genomic instability affecting the 3' exonic end of CSF3R, the endogenous Csf3R, and the endogenous Runx1 in Ba/F3 cells that could account for these targets being mutational hotspots. We conclude that other mechanisms, such as stochastic events, result in mutations of CSF3R drive the evolution of SCN to MDS/AML. Disclosures No relevant conflicts of interest to declare.

Donor Clonal Hematopoiesis Increases Risk of Acute Graft Versus Host Disease after Matched Related Transplantation in AML and MDS Patients

Oran: AROG pharmaceuticals: Research Funding; Astex pharmaceuticals: Research Funding. Champlin:Sanofi-Genzyme: Research Funding; Actinium: Consultancy; Johnson and Johnson: Consultancy. 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. Kantarjian:Amgen: Honoraria, Research Funding; Agios: Honoraria, Research Funding; BMS: Research Funding; Jazz Pharma: Research Funding; Novartis: Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria; Ariad: Research Funding; Daiichi-Sankyo: Research Funding; Astex: Research Funding; Cyclacel: Research Funding; Immunogen: Research Funding; Pfizer: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding. Popat:Jazz: Consultancy; Incyte: Research Funding; Bayer: Research Funding. Takahashi:Symbio Pharmaceuticals: Consultancy.

Feasibility and Outcomes of T-Cell Depleted Hematopoietic Stem Cell Transplantation in Patients with Relapsed or Refractory AML and High Risk MDS

Feasibility and Outcomes of T-Cell Depleted Hematopoietic Stem Cell Transplantation in Patients with Relapsed or Refractory AML and High Risk MDS

A Phase 1 Dose Escalation Study of Milademetan in Combination with 5-Azacitidine (AZA) in Patients with Acute Myeloid Leukemia (AML) or High-Risk Myelodysplastic Syndrome (MDS)

A Phase 1 Dose Escalation Study of Milademetan in Combination with 5-Azacitidine (AZA) in Patients with Acute Myeloid Leukemia (AML) or High-Risk Myelodysplastic Syndrome (MDS)

Population-Based, Cause-Specific Risk of Non-Lymphoma Deaths Among 20,491 Adults with Classical Hodgkin Lymphoma (cHL) Treated with Initial Chemotherapy in the United States, 2000-2015

Introduction: Advances in cHL treatment over the past 50 years have been fueled, in part, by recognition of long-term treatment-related complications that emerged after cure of cHL became a reality. While cHL-specific survival has continued to improve with time, premature death following diagnosis and treatment of cHL remains life-limiting. Most studies of cHL mortality have focused on long-term survivors and included patients treated with chemotherapy approaches and radiation techniques used in the past. Therefore, we sought to comprehensively quantify early and late cause-specific risks of death among U.S. adults with cHL treated with chemotherapy during a treatment era predominated by ABVD-based (doxorubicin, bleomycin, vinblastine, dacarbazine) chemotherapy. Methods: We used data from 17 cancer registry areas of the Surveillance, Epidemiology, and End Results Program to quantify risks of death among individuals diagnosed with early (I/II) or advanced (III/IV) stage cHL between ages 20-74 years and treated with initial chemotherapy during 2000-2015. We calculated standardized mortality ratios (SMRs) and 95% confidence intervals to compare cause-specific risk of death following cHL to that expected in the general U.S. population and estimated absolute excess risks (per 10,000 patient-years) to quantify disease-specific death burden. Results: Among 24,205 cHL patients, we assessed mortality among the 85% (n=20,491) treated with initial chemotherapy (37% of the 20,491 also received initial radiotherapy). With a mean follow-up of 6.7 years, we observed 3,230 deaths due to lymphoma (n=1,936), other neoplasms (n=273), noncancers (n=937), and unknown (n=84) causes. The risk of non-lymphoma deaths overall was significantly elevated 1.5- and 2.3-fold among adults diagnosed with early or advanced cHL, respectively, representing 20 (early stage) and 75 (advanced stage) excess deaths/10,000 patient-years. The most common causes of noncancer deaths were attributed to cardiovascular (n=284), respiratory (n=166), and infectious (n=119) diseases and accidents/falls/adverse events (n=121). The greatest increased risk of cardiovascular deaths was observed for heart disease &lt;1-year after cHL which persisted 1-4 and &gt;5 years after early and advanced stage cHL. Death from interstitial lung disease (ILD) significantly exceeded the expected rate by 14- and 24-fold in early and advanced stage cHL, respectively, most notably within the first year of diagnosis (SMRearly=90; SMRadvanced=128), with SMRs decreasing substantially after 1-year but remaining significantly increased in both stage groups. Patients were also prone to infection-related deaths irrespective of early (SMRearly=2.2) or advanced (SMRadvanced=3.9) cHL, both &lt;1 or &gt;1 year after diagnosis, with the greatest excesses occurring within the first year. Individuals with early (SMRearly=1.8) and advanced stage (SMRadvanced=4.2) disease had significantly elevated risks of death from adverse events (deaths coded as sequelae of drug, treatment, or other specified exposure), most notably &lt;1 year after cHL diagnosis (SMRearly=7.5; SMRadvanced=17.5). Among non-lymphoma neoplasms, death from myelodysplastic syndromes/acute myeloid leukemia (MDS/AML) was significantly increased among early (SMRearly=5.2) and advanced stage (SMRadvanced=8.6) cHL. No MDS/AML deaths occurred within 1-year of cHL, but risks increased to &gt;9-fold among both stage groups 1-4 years after diagnosis, and excesses persisted at &gt;5-years among those with advanced stage cHL (SMRadvanced=9.1). Lung cancer accounted for the majority of solid tumor deaths among those with early (SMRearly=1.4) and advanced stage (SMRadvanced=1.9) cHL, with heightened risks beginning at &gt;5 years among early stage cHL and at 1-4 years among advanced stage disease. Conclusion: Despite tailored treatment approaches in an ABVD-predominant era, risk of non-lymphoma deaths remains significantly elevated among cHL patients 20-74 years of age in the U.S., with early or advanced stage disease, and &lt;1 or &gt;1 year from diagnosis. Our data strongly support implementation of preventive and supportive measures following cHL diagnosis and continued refinement of treatment approaches to minimize premature deaths. Disclosures No relevant conflicts of interest to declare.

Long-Term Outcome of Patients with Low-Grade Follicular Lymphoma Treated with Yttrium-90 Ibritumomab Tiuxetan: The Mayo Clinic Experience

Background Follicular lymphoma (FL) is the second most common lymphoma accounting for approximately 15% of all non-Hodgkin's lymphoma (NHL). Yttrium-90 ibritumomab tiuxetan [(90)Y-IT; Zevalin] is a radio-immunoconjugate (RIC) which targets CD20. It is approved in relapsed/refractory low-grade NHL and as consolidation after upfront induction chemoimmunotherapy for FL. This study analyzed patients with previously untreated (UFL) or relapsed/refractory low-grade FL (RFL) treated at our institution with (90)Y-IT. It represents the largest reported cohort for therapeutic use of (90)Y-IT in low-grade FL. Methods Medical records of patients with low-grade FL (WHO grade 1-2) who received treatment with (90)Y-IT at Mayo Clinic Cancer Center between January 2003 and December 2018 were analyzed. Overall response rate (ORR) and complete response rate (CR) were calculated. Progression-free survival (PFS), time to next therapy (TTNT), and overall survival (OS) were analyzed using the Kaplan-Meier method. Results Our cohort consists of 137 patients - 29% (40/137) with UFL and 71% (97/137) with RFL. The median age at diagnosis was 60 years (range, 18-86) with 54% (74/137) males. The median number of previous treatments in RFL patients was 1 (range, 1-5). ECOG performance status at the time of treatment was 0 in 90% and 1 in 10% of patients. 87% (119/137) had stage III/IV disease at the time of (90)Y-IT therapy. The median follow up from the time of (90)Y-IT therapy was 10.2 years (95% CI; 8.8, 11.6); 69% (95/137) of patients are alive. The ORR was 100% in UFL with 93% (37/40) CR while ORR in UFL was 93% (90/97) with 73% (71/97) CR. 45% (48/108) of the CR patients remain in continuous CR (CCR) with a median follow-up of 7 years (95% CI; 5.2, 9.9). CCR was observed in 55% (22/40) of UFL patients compared to 27% (26/97) of RFL patients. 63% (86/137) of patients had relapsed. More relapses occurred in the RFL group (69/97; 71%) compared to the UFL group (17/40; 43%), (p=0.002). In the entire cohort, the median PFS was 2.5 years (95% CI; 2.1, 3.5) and TTNT was 3.6 years (95% CI; 2.5, 4.7). Median PFS was significantly higher in UFL group compared to RFL group- 4.1 years (95% CI; 2.3, NR) vs 2.2 years (95% CI; 1.6, 3.1), respectively (Figure 1-A). Median TTNT was higher in UFL group compared to RFL group- NR (95% CI; 4.1 years, NR) vs 2.4 years (95% CI; 2, 3.6), respectively (Figure 1-B). Median OS (entire cohort) was 18 years (95% CI; 15.8, NR) with no statistically significant difference between UFL group and RFL group; NR (95% CI; NR, NR) vs 18 years (95% CI; 12.3, 20.5), respectively (Figure 1-C). Transformation to high grade lymphoma was seen in 19% (18/97) in RFL group compared to 2.5% (1/40) in UFL group, (p=0.005). Median time to transformation was 4.3 years (range, 1-11). More patients developed therapy-related myelodysplastic syndrome/acute myeloid leukemia (MDS/AML) in the RFL group 14% (14/97) compared to 2.5% (1/40) in the UFL group (p= 0.02). Median time to develop MDS/AML was 3.3 years (range, 0-9.7). Grade ³3 neutropenia was observed in 46% of patients with median time to recovery of 21 days (range, 2-706). Grade ³3 thrombocytopenia was observed in 47% of patients with median time to recovery of 23 days (range, 7-548). Eighteen patients required growth factors support and 14 required transfusions. Non-hematologic AEs included mild to severe fatigue in 35 patients. Conclusion Radio-immunoconjugate therapy with (90)Y-IT is an effective single-agent regimen for low-grade FL. The response and survival data in this large real-world cohort is superior to the pivotal trials of this agent conducted nearly 20 years ago. The data in untreated FL is also of interest and provides the rationale for our current randomized phase 2 trial in untreated FL (https://clinicaltrials.gov/show/NCT02320292). Long-term complete remission (&gt;7 years) was seen in 35% of the study population. Based on these promising results, clinical trials combining RIC with novel agents that could potentiate its effects are warranted. Figure 1 (A) Progression-free survival; comparing time to progression or death after (90)Y-IT treatment between previously untreated patients (UFL) and patients with relapsed/refractory FL (RFL), (B) Time to next therapy; comparing time to starting next line of treatment after (90)Y-IT treatment between UFL and RFL, (C) Overall survival; comparing time to death from all causes after (90)Y-IT treatment between UFL and RFL. Figure 1 Disclosures Tun: DTRM Biopharma: Research Funding; TG Therapeutics: Research Funding; BMS: Research Funding; Curis: Research Funding; Celgene: Research Funding; Mundi-pharma: Research Funding. OffLabel Disclosure: Yttrium-90 ibritumomab tiuxetan [(90)Y-IT; Zevalin] is a radio-immunoconjugate (RIC) which targets CD20. It is approved in relapsed/refractory low-grade NHL and as consolidation after upfront induction chemoimmunotherapy for FL. We are discussing its use as a frontline therapy in low grade FL.

A Phase I Study of CC-90002, a Monoclonal Antibody Targeting CD47, in Patients with Relapsed and/or Refractory (R/R) Acute Myeloid Leukemia (AML) and High-Risk Myelodysplastic Syndromes (MDS): Final Results

A Phase I Study of CC-90002, a Monoclonal Antibody Targeting CD47, in Patients with Relapsed and/or Refractory (R/R) Acute Myeloid Leukemia (AML) and High-Risk Myelodysplastic Syndromes (MDS): Final Results

Comparison of a New Reduced Toxicity Myeloablative Treosulfan and Fludarabine Preparative Regimen with Myeloablative Busulfan or Melphalan in Combination with Fludarabine in Older Patients with Acute Myeloid Leukemia or Myelodysplastic Syndromes: A Retrospective Matched Pair Analysis of Patients from a Prospective Randomized Trial and the European Blood and Marrow Transplantation Society Registry

Background The best preparative regimen for the growing number of older acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) patients undergoing allogeneic hematopoietic cell transplantation (HCT) from matched related (MRD) or unrelated donors (MUD) remains undefined. A large randomized phase III trial (MC-FludT.14/L study: ClinicalTrials.gov Identifier: NCT00822393) recently demonstrated that myeloablative intravenous (IV) treosulfan (10 g/m² IV on days -4 to -2) in combination with fludarabine (TreoFlu) improves outcome in older and/or comorbid patients with AML in complete remission (CR) or MDS compared with the reference reduced intensity busulfan (0.8 mg/kg IV in 6-hour intervals on days -4 and -3) and fludarabine (30 mg/m² IV on days -6 to -2 in each study arm) regimen. The beneficial effect of the TreoFlu regimen resulted from a significantly reduced non-relapse mortality (NRM) and translated to improved event-free survival (EFS) and overall survival (OS) (Beelen DW et al The Lancet Haematology, 2019). These results raised the question, how this new regimen compares to broadly applied myeloablative regimens, namely busulfan (0.8 mg/kg IV in 6-hour intervals over 4 days) plus cyclophosphamide (120 mg/kg IV over 2 days) (BuCy) or melphalan (140 mg/m² IV over 1 day or 2 days) plus fludarabine (MelFlu) in older AML and MDS patients. To address this question, we performed a comparative analysis of MC-FludT.14/L study patients treated with the TreoFlu regimen and similar patients of the European Blood and Marrow Transplantation Society (EBMT) registry, who underwent HCT from MRD or MUD after the BuCy or MelFlu regimen between 2010 and 2016. Patients and Methods Inclusion criteria were essentially the same as for the MC-FludT.14/L-study (patient age 50 to 70 years [yrs], primary or secondary AML in CR or MDS, Karnofsky-index ≥ 60%, MRD or MUD, 1st HCT). The study objectives were to compare OS, relapse incidence (RI), and NRM at 2 yrs after HCT between the TreoFlu regimen and the BuCy or MelFlu regimen. A total of 1493 EBMT registry patients (median age 58 yrs, AML: n=1135 [76%], MDS: n=358 [24%]) were identified for the comparison with the 252 MC-FludT.14/L patients (median age 61 yrs, AML: n=174 [69%], MDS: n=78 [31%]). A 1:1 matching method based on propensity scores (PS) with 14 patient-, donor-, and disease-characteristics was used to reduce confounding due to differences between regimens and was performed separately for AML and MDS patients. With the exception of comparison between the TreoFlu and BuCy regimen in AML patients, a significantly higher proportion of patients in the TreoFlu regimen subsets had a HCT-comorbidity index &gt; 2 compared to patient subsets treated with the BuCy or MelFlu regimen. Results For patients with AML, the 2-yrs OS estimate was significantly higher after the TreoFlu compared with the BuCy regimen (76.4%, 95%-confidence interval [95%-CI]: 66.8% - 85.9% vs 49.2%, 95%-CI: 36.4% - 62.1%, p&lt;0.001) and MelFlu regimen (72.7%, 95%-CI: 63.7% - 80.7% vs 58.7%, 95%-CI: 48.3% - 69.1%, p=0.04). This was clearly related to the significantly lower 2-yrs NRM estimate after the TreoFlu compared with the BuCy regimen (3.9%, 95-CI: 0% - 8.2% vs 23.5%, 95%-CI: 13.1% - 33.9%, p&lt;0.001) and MelFlu regimen (6.4%, 95-CI: 1.8% - 11.0% vs 17.5%, 95%-CI: 9.6% - 25.5%, p&lt;0.02). For patients with MDS, the differences of the 2-yrs OS and NRM estimates between patient subsets were similar, but were only significant for the comparison of the OS estimate between the TreoFlu and BuCy regimen (72.0%, 95%-CI: 54.4% - 89.6% vs 30.5, 95%-CI: 6.1% - 54.9%, p&lt;0.01). The adjusted hazard ratios of 2-yrs overall mortality and NRM between regimens including all eligible patients by multivariate sensitivity analysis based on Cox proportional hazards models are given in the table below. Notably, no differences between the respective 2-yrs RI were detectable when comparing these patient subsets. Conclusion In older AML and MDS patients, the new TreoFlu regimen compares favorable to the broadly applied myeloablative BuCy and MelFlu regimens. The substantially lower 2-yrs NRM estimate supports its superior tolerability in this patient population. This large retrospective comparative analysis provides a basis for properly designed randomized trials of the new toxicity reduced myeloablative TreoFlu regimen in comparison with other myeloablative regimens in this target population. Table Disclosures Beelen: Medac GmbH Wedel Germany: Consultancy, Honoraria. Stoelzel:Neovii: Other: Travel funding; Shire: Consultancy, Other: Travel funding; JAZZ Pharmaceuticals: Consultancy. Dreger:MSD: Membership on an entity's Board of Directors or advisory committees, Other: Sponsoring of Symposia; Neovii, Riemser: Research Funding; AbbVie, Gilead, Novartis, Riemser, Roche: Speakers Bureau; AbbVie, AstraZeneca, Gilead, Janssen, Novartis, Riemser, Roche: Consultancy.

Efficacy of Venetoclax Combination Therapy with Hypomethylating Agents in Patients with Relapsed Acute Myeloid Leukemia after Allogeneic Hematopoietic Cell Transplantation

Introduction: Venetoclax (VEN), a selective BCL-2 inhibitor, in combination with hypomethylating agents (HMA) has high efficacy in treatment-naïve elderly patients with acute myeloid leukemia (AML). The role for VEN in patients with relapsed/refractory (R/R) AML, myelodysplastic syndrome (MDS), or other myeloproliferative neoplasms remains incompletely defined. In particular, the efficacy of VEN+HMA has not been studied systematically in patients who experience AML relapse following allogeneic hematopoietic cell transplantation (HCT). Method: All patients treated with VEN+HMA (azacitidine or decitabine) for R/R de novo or secondary AML or progressive MDS following allogeneic HCT were identified and reviewed retrospectively. All included AML patients had overt clinical relapse with ≥ 5% bone marrow blasts or extramedullary disease biopsy proven to be AML. Patients were included in this analysis if they received at least 14 days of VEN therapy. Results: Eleven patients with median age 66 (range 25-75) were treated for R/R AML post-allogeneic HCT. Transplant characteristics included use of reduced intensity conditioning in 10/11 (91%), matched sibling donors in 5/11 (45%), matched unrelated donors in 5/11 (45%), and cord blood in 1/11 patients. The median time from HCT to relapse/disease progression was 7 months (range 3-36). Two patients had extramedullary relapse only, and the remainder had marrow involvement. Eight patients (73%) received azacitidine and 3 (27%) received decitabine in combination with VEN. All but two patients (82%) had prior HMA exposure and most received VEN+HMA as initial post-transplant salvage therapy (64%). Only one patient received donor lymphocyte infusion in conjunction with VEN+HMA therapy, and none proceeded to a second allotransplant. Nine patients (82%) experienced an objective response, which included 4 CR/CRi (36%) and 5 PR/SD (45%). In patients with CR/CRi, three patients had adverse risk cytogenetics and one had a favorable risk profile at diagnosis consisting of normal cytogenetics with an isolated NPM1 mutation. All patients who failed to remit with VEN+HMA had intermediate- or high-risk genetic features. The median number of treatment cycles given was 3 (range 1-20). Median survival was 11 months and estimated 6-month and 12-month survival was 82% and 36%, respectively. Three patients remain alive with median 16.5 months follow-up (range 2.5-32). Conclusion: Venetoclax in combination with HMA is a viable salvage option in patients with relapsed AML or progressive MDS after allogeneic HCT, including those with prior exposure to HMA. Although one patient in this cohort sustained long term complete remission, overall prognosis remains dismal in this high-risk patient population and improved treatment options for relapsed/refractory AML following alloHCT remain needed. Disclosures Damon: Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Martin:Amgen, Sanofi, Seattle Genetics: Research Funding; Roche and Juno: Consultancy. Olin:MedImmune: Research Funding; Ignyta: Research Funding; Clovis: Research Funding; AstraZeneca: Research Funding; Revolution Medicine: Consultancy; Daiichi Sankyo: Research Funding; Astellas: Research Funding; Genentech: Consultancy, Research Funding; Pfizer: Research Funding; Jazz Pharmaceuticals: Consultancy, Honoraria; Novartis: Research Funding; Mirati Therapeutics: Research Funding; Spectrum: Research Funding. Smith:Astellas Pharma: Research Funding; Abbvie: Research Funding; fujiFilm: Research Funding; Revolution Medicines: Research Funding. Logan:Amgen: 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; Novartis: Consultancy; Pharmacyclics: Research Funding; Astellas: Research Funding; Jazz: Research Funding; Kite: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees; TeneoBio: Consultancy; Kiadis: Consultancy; Kadmon: Research Funding; Abbvie: Consultancy.

Estimated Glomerular Filtration Rate Is an Independent Predictor of Outcome in High-Risk Myelodysplastic Syndrome (MDS) and Low Blast Count Acute Myeloid Leukaemia (AML) Patients Treated with Azacytidine (AZA). a Retrospective Study from the MDS Registry of the Hellenic MDS Study Group

Introduction. Myelodysplastic Syndrome (MDS) is a disease of the elderly. Apart from IPSS, IPSS-R and WPSS, several indexes incorporating patient comorbidities (such as the MDS CI index- Della Porta et al Haematologica 2011, the HCT-CI index - Sorror et al Blood 2005) and performance status (the GFM index- Itzykson et al Blood 2011) have been used to predict outcome in MDS patients treated with azacytidine (AZA). We sought to investigate the effect of comorbidities on the outcome after AZA in a large group of patients from the MDS registry of the Hellenic MDS Study Group. Methods. The present study has been conducted as a retrospective observational cohort one. It included high-risk MDS and low blast count AML patients treated with AZA from 26 centers in Greece from 2007 to 2018. T-test and ANOVA were used to compare scale variables between two or more groups respectively. Univariate analysis of nominal and scale survival data was performed using Kaplan-Meier survival curves and Cox regression respectively. All variables achieving p&lt;0.05 at univariate analysis were considered eligible for multivariate analysis; the latter was based on Cox regression method. Results. We analyzed 536 consecutive patients. Patient characteristics are depicted in Table 1. The median follow-up period was 27.5±4.8 months. 371 patients received at least four cycles of AZA and 165 patients received less than 4 cycles of AZA. Patients who received ≥4 cycles of AZA did not differ from those who received &lt;4 cycles regarding gender, age, estimated Glomerular Filtration Rate (eGFR), cardiovascular, renal, and tumor comorbidities. Significantly higher IPSS-R and GFM scores at baseline were found in the group of patients receiving &lt; 4 cycles of AZA compared to patients who received ≥ 4 cycles of AZA (p=0.042 and 0.05 respectively), while transfusion dependence at baseline occurred more often in patients who received ≥ 4 cycles of AZA (p=0.039). To assess the prognostic significance of risk factors on leukemia free survival (LFS) and overall survival (OS), univariate and multivariate analysis for the whole population was performed, as well as a landmark analysis for patients who were treated with at least 4 cycles of AZA. ECOG performance status and the presence of peripheral blasts were independent prognostic factors for LFS and OS for the whole cohort analysis while response to AZA and the presence of peripheral blasts were independent prognosticators for LFS and OS in the landmark analysis. In addition, prior low dose cytarabine was an independent adverse prognostic factor for LFS in the landmark analysis. As regards comorbidities, neither of MDS-CI, HCT-CI and GFM systems independently predicted LFS or OS in either analysis, but eGFR with a cut-off of 45 ml/min was a strong and independent prognosticator for LFS and OS in both the standard and the landmark analysis. Kaplan-Meier survival curves regarding LFS and OS at AZA initiation and landmark analysis after 4th cycle of AZA in relation with eGFR are shown in Figure 1. Conclusion. This is the first study to demonstrate the importance of eGFR at baseline as a prognostic marker for LFS and OS in high-risk MDS and low-blast AML patients treated with AZA. The role of comorbidities and PS needs to be further evaluated in this patient group. Disclosures Symeonidis: Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; 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; Tekeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Vassilakopoulos:Novartis: 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; WinMedica: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene / GenesisPharma: 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; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Panayiotidis:Bayer: Other: Support of clinical trial. Pappa:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Research Funding; Gilead: Honoraria, Research Funding; Novartis: Honoraria, Research Funding, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene / GenesisPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Kotsianidis:Celgene: Research Funding.

Ivo-Nivo: A Phase II Study of the IDH1 Inhibitor Ivosidenib (AG-120) in Combination with the Checkpoint Blockade Inhibitor Nivolumab for Patients with IDH1 Mutated Relapsed/Refractory AML and High Risk MDS

Background: The normal function of isocitrate dehydrogenase 1 (IDH1) is to catalyze the conversion of cytoplasmic isocitrate to α-ketoglutarate (aKG) in the Krebs cycle. In hematologic malignancies a hotspot mutation at arginine 132 within the conserved active site of IDH1 leads to loss of the expected Krebs Cycle reaction as well as production of the oncometabolite 2- hydroxyglutarate (2-HG). In acute myeloid leukemia (AML) increased cellular 2-HG levels has been shown to impact the tumor microenvironment and promotes tumorigenesis via paracrine stimulation as well repression of the tumor associated immune system. Ivosidenib (AG-120) is a small molecule inhibitor of mIDH1 and is FDA approved for the treatment of patients (pts) with relapsed refractory IDH1 mutant AML. Ivosidenib is known to lower 2-HG levels, independent of response. By reducing 2-HG levels that promote immune escape of IDH-mutant tumors with ivosidenib, we hope to harness the known programmed death receptor pathway dysregulation in AML and high risk myelodysplastic syndrome (MDS). Study Design and Methods: IVO-NIVO is a single arm, multi-institutional phase II investigator initiated clinical trial with a safety cohort to confirm safety and tolerability of combination AG-120 and nivolumab. To be included pts must have MDS or AML with a documented IDH1 mutation in blood or bone marrow within 30 days of inclusion based on mutational testing by PCR or sequencing in a CLIA certified laboratory and be willing to undergo a bone marrow biopsy. Pts will initially start therapy with AG-120, 500mg by mouth daily for 1 cycle. A cycle is defined as 28 days of therapy. On cycle 2 day 1 enrolled pts will receive nivolumab 480 mg that will subsequently be infused every four weeks. Disease response to treatment will be serially assessed through the evaluation of blood (at least monthly) and bone marrow biopsies and aspirates. A complete response assessment will be performed after 6 cycles of therapy. Transplant eligible pts may proceed to allogeneic stem cell transplant (ASCT) if complete response (CR) or morphologic complete remission with incomplete count recovery (CRi) is achieved. Pts that are not eligible for ASCT will continue to receive AG-120- nivolumab combination therapy until documented progression or unacceptable toxicity (figure 1). Safety Cohort: We will have an interim safety analysis after the first 6 pts finishing the first cycle of combination therapy to ensure dosing is safe and tolerable. Pts will undergo clinical assessment with each cycle of therapy, with particular attention to known toxicities like differentiation syndrome that may be life threatening. If 0 to 1 of the first 6 subjects experienced unacceptable toxicities the study will continue as planned. If 2 pts experienced unacceptable toxicities, accrual will be temporarily suspended in order to conduct a review of safety data. If after review, a safety issue is identified and can be corrected, the protocol will be amended accordingly, and enrollment will restart. If an additional 2 pts (4 of 12) or more experience an unacceptable toxicity the patient will be taken off trial and the trial will be terminated. Statistical plan: It is estimated that 45 pts will be enrolled on trial. Using optimal Simon Stage 2 minimax design, if less than 7 of the first 16 pts respond the treatment will be study will be stopped for futility (type 1 error 0.05, type 2 error 0.2). Primary endpoint: We aim to improve the cumulative response rate after 6 cycles of therapy from 40% to 60% (Two-sided alpha risk of 0.05, 1-Beta of 0.8 = 38 pts + 7 additional pts for potential drop-off observed in prior studies) in pts with mIDH1 relapsed/ refractory AML and MDS. Based on published data, it is known that overall response rate is approximately 40% to single agent AG-120 in the relapsed/ refractory IDH1 mutant AML population. Therefore, we expect a 20% ORR improvement compared to historical control after 6 cycles of treatment, based on MDS International Working Group 2006 criteria and AML MDS International Working group MDS/AML criteria. Secondary endpoints: Progression-free survival (the interval between the time of initiation of olaparib to the time of documentation of olaparib failure or last follow-up), overall survival (the interval between the time of initiation of olaparib to the time of death or last follow-up) and percentage of pts that can be bridged to ASCT. Disclosures Prebet: novartis: Honoraria; Jazz Pharmaceuticals: Consultancy, Honoraria, Research Funding; pfizer: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; Boehringer Ingelheim: Research Funding; Genentech: Consultancy; novartis: Honoraria; pfizer: Honoraria; novartis: Honoraria; Boehringer Ingelheim: Research Funding; novartis: Honoraria; pfizer: Honoraria; pfizer: Honoraria; Tetraphase: Consultancy; Agios: Consultancy, Research Funding; pfizer: Honoraria; novartis: Honoraria; Boehringer Ingelheim: Research Funding. OffLabel Disclosure: We will use Ivosidenib and nivolumab in combination as a part of a clinical trial to improve care of patients with relapsed/ refractory AML and MDS

The PRIME Trial: PARP Inhibition in IDH Mutant Effectiveness Trial. a Phase II Study of Olaparib in Isocitrate Dehydrogenase (IDH) Mutant Relapsed/Refractory Acute Myeloid Leukemia and Myelodysplastic Syndrome

Background: Recurring mutations have been identified in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) which translate to therapeutic targets. Isocitrate dehydrogenase-1 and -2 (IDH1/2) mutations occur in ~20% of AML, and up to 12% of patients with MDS. Three conserved mutational hotspots in the IDH enzymes alter their function and lead to the production of (R)-2-hydroxyglutarate (2HG), an oncometabolite with numerous downstream effects, including impaired DNA damage repair. Specifically, homologous recombination (HR) is impaired by inhibiting the function of histone demethylases that are critical for HR and recruitment of the HR machinery to sites of DNA damage. In HR deficient tumors poly-ADP ribose polymerase (PARP) enzymes mediate a key salvage pathway. PARP inhibition in HR deficient tumors leads to synthetic lethality via simultaneous inhibition of HR and SSB mediated DNA repair. Our group previously demonstrated synthetic lethality with PARP inhibition in IDH mutant cells lines, and other IDH mutant models including primary patient-derived cell lines and genetically-matched tumor xenografts. Study Design and Methods: The PRIME trial (NCI10264) is a proof of concept, biomarker-driven, multi-institution, phase II open label clinical trial to assess the overall response of IDH1/2 mutant relapsed/refractory AML and MDS to PARP inhibitor monotherapy with olaparib. The clinical trial is executed by the Experimental Therapeutics Clinical Trials Network of the NCI. The Cancer Therapy Evaluation Program will provide olaparib. Eligibility criteria include documented IDH1 or IDH2 mutation in blood or bone marrow within 30 days of enrollment based on mutational testing by PCR or sequencing in a CLIA certified laboratory and willingness to undergo a bone marrow biopsy. Patients will be treated with olaparib 300 mg q12hrs each day of a 28-day cycle, using a tablet formulation, until disease progression, unacceptable toxicity, withdrawal of consent or death. Blood and bone marrow samples for 2-HG analysis will be collected prior to starting therapy and after 1 cycle (28 days), cycle 2, 3, 6, 9, 12 or when there is concern for disease progression (Figure 1). A Simon two-stage optimal design will be used to test the null (ORR=10%) versus the alternative hypothesis (ORR=40%) in each arm. In the first stage, 9 patients will be accrued in each arm. If one or fewer responses are observed in these 9 patients, that arm will be stopped early for futility. Otherwise, 11 additional patients will be accrued for a total of 18 in each arm. We reject the null hypothesis if at least 5 responses are observed in these 20 patients. In each arm, we have approximately 90% power to detect a 30% increase in ORR at a one-sided type I error rate of 0.05. Primary endpoint: Overall response rate (ORR) of 40%, i.e., a 30% ORR improvement (40% vs. historical control ORR = 10%) based on MDS International Working Group 2006 criteria and AML MDS International Working Group 2003 criteria after 6 cycles of treatment. Cumulative ORR will include complete remission, complete remission with incomplete blood count recovery, partial response, and bone marrow complete remission. Secondary endpoints: Progression-free survival (the interval between the time of initiation of olaparib to the time of documentation of olaparib failure or last follow-up) and overall survival (the interval between the time of initiation of olaparib to the time of death or last follow-up) for the trial. Exploratory studies: The PRIME trial will also test the utility of 2-HG and DNA damage markers such as γ-H2AX as potential biomarkers of response to olaparib. Using multiple viability assays on leukemia cell lines and bone marrow cultures we will assess synergistic therapeutic combinations to further improve outcomes in this patient population. To confirm efficacy in vivo without undue toxicity, promising combination therapies will be confirmed in cytokine-humanized immunodeficient "MISTRG" mice. We will also examine the impact of PARP inhibitors on the genomic, proteomic, metabolomic and immunologic landscape of IDH 1/2-mutant hematologic malignancies using DNA whole exome sequencing (WES), RNA-Seq, and liquid chromatography-mass spectrometry assessment of oncometabolites. Disclosures Bindra: Cybrexa: Consultancy, Equity Ownership. Prebet:pfizer: Honoraria; pfizer: Honoraria; pfizer: Honoraria; Boehringer Ingelheim: Research Funding; pfizer: Honoraria; Tetraphase: Consultancy; novartis: Honoraria; novartis: Honoraria; Genentech: Consultancy; Boehringer Ingelheim: Research Funding; novartis: Honoraria; Boehringer Ingelheim: Research Funding; Agios: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Honoraria, Research Funding; pfizer: Honoraria; novartis: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; novartis: Honoraria. OffLabel Disclosure: We will be using PARP inhibitors as a novel therapy for patients with relapsed or refractory AML and high risk MDS based on preclinical data.