Abstract: Nodal peripheral T-cell lymphomas (PTCL), the most common PTCLs, are generally treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-based curative-intent chemotherapy. Recent molecular data have assisted in prognosticating these PTCLs, but most reports lack detailed baseline clinical characteristics and treatment courses. We retrospectively evaluated cases of PTCL treated with CHOP-based chemotherapy that had tumors sequenced by the Memorial Sloan Kettering Integrated Mutational Profiling of Actionable Cancer Targets next-generation sequencing panel to identify variables correlating with inferior survival. We identified 132 patients who met these criteria. Clinical factors correlating with an increased risk of progression (by multivariate analysis) included advanced-stage disease and bone marrow involvement. The only somatic genetic aberrancies correlating with inferior progression-free survival (PFS) were TP53 mutations and TP53/17p deletions. PFS remained inferior when stratifying by TP53 mutation status, with a median PFS of 4.5 months for PTCL with a TP53 mutation (n = 21) vs 10.5 months for PTCL without a TP53 mutation (n = 111). No TP53 aberrancy correlated with inferior overall survival (OS). Although rare (n = 9), CDKN2A-deleted PTCL correlated with inferior OS, with a median of 17.6 months vs 56.7 months for patients without CDKN2A deletions. This retrospective study suggests that patients with PTCL with TP53 mutations experience inferior PFS when treated with curative-intent chemotherapy, warranting prospective confirmation.

Abstract: Background: Fit patients (pts) with mantle cell lymphoma (MCL) are commonly treated with immunochemotherapy and consolidative high-dose therapy + stem cell rescue (cHDT/SCR), yet this approach has not demonstrated an overall survival (OS) benefit in a randomized trial. Outcomes for pts with high-risk MCL (TP53 aberrancy, high proliferation index, blastic histology) after cHDT/SCR are poor, and not all pts with MCL are eligible for this approach. Methods: We conducted a phase II study of sequential immunochemotherapy incorporating lenalidomide enriching for pts with high-risk disease features (defined as blastoid/pleomorphic histology and/or Ki67 & gt;=30%). The three phases of tx were: 1) lenalidomide (15 mg daily, days 1-14) plus R-CHOP for four 21-day cycles; 2) R-HiDAC for 2 cycles (initially age-based cytarabine 1-3 g/m2; 3 g/m2 dose removed after 16 pts due to hematologic toxicity); and 3) rituximab monthly plus lenalidomide (15 mg daily) for 6 months (mos). Eligibility requirements were untreated stage II-IV MCL, KPS ≥70%, and adequate organ function; we sought ≥2/3 high-risk pts. We performed MRD testing on peripheral blood (cellular DNA) using the clonoSEQ Assay (Adaptive Biotechnologies). We obtained PET/CT and MRD testing after each phase of treatment and also MRD evaluation at 6 mos post-rituximab + lenalidomide maintenance. The primary endpoint was the rate of 3-yr progression-free survival (PFS), (acceptable PFS ≥75%, unacceptable ≤60%, based on desired proportion of high-risk pts). Results: Among 49 pts enrolled, 47 were evaluable for PFS (1 had progressive disease (PD) and 1 had toxicity during len-R-CHOP). Characteristics for 47 evaluable pts are shown in Table 1: 64% were high-risk and 18% had TP53 mutation. 45 completed maintenance (1 had PD during R-HiDAC and 1 withdrew to pursue cHDT/SCR) and 43 achieved complete response (CR), 1 stable disease, and 1 PD at end of treatment (EoT), yielding overall response rate of 91%, all CR (Figure 1). With a median follow-up of 2.8 yrs among survivors, the 3-yr PFS was 64% (95 CI 50, 82) and OS 85% (95 CI 74, 99). Three-yr PFS differed by TP53 status (14% mut vs. 85% wt, P & lt; 0.0001, Table 2). Of 4 pts with PD, 3 had TP53 mutation and 1 had an unknown mutation status. Among TP53 wt pts, there was no significant difference in outcomes by risk (Table 2). MRD results were not obtained in 4 pts. Among 45 pts with MRD results, tumor clonal characterization for MRD evaluation was successful in 87% (39/45). MRD results are shown in Figure 2. Examining the initial phase of treatment (len-R-CHOP and R-HiDAC), among 37 pts with results at 1x10-5 sensitivity (1E5) following len-RCHOP, a substantial proportion (32%, 12/37 pts) remained MRD+ and 11 of 12 MRD+ pts post len-RCHOP converted to MRD- following R-HiDAC. At 1x10-6 sensitivity (1E6) following R-HiDAC, 5/20 pts were MRD+, and among responding pts, shorter median PFS was observed in MRD+ versus MRD- pts (23.1 mos vs. NR, P = 0.03). Examining the final phase of treatment (rituximab + lenalidomide maintenance) and observation period, among 37 pts with MRD results at 1E5 at EoT, 4 were MRD+, 2 of which were simultaneous (within 2 weeks of testing) with relapse; the remaining two MRD+ pts had median PFS 4.9 mos versus 37.4 mos for the 32 non-relapsed MRD- pts (P & lt; 0.001). At 1E6, 6 pts who were MRD- at EoT converted to MRD+ after 6 mos of observation. MRD status at 1E6 at 6-mos post-EOT correlated with PFS: among 20 non-relapsed pts (6 MRD+, 14 MRD-), median PFS was 30.8 mos for MRD- versus 13.2 mos for MRD+ (P = 0.02). Conclusions: In a novel approach of sequential immunochemotherapy plus lenalidomide enrolling majority high-risk pts, outcomes for TP53-mutant pts were poor and we did not reach our primary endpoint of 3-yr PFS ≥75%. Among TP53-wt pts, this treatment program was highly effective even among pts with elevated Ki-67 ( & gt;=30%) and was associated with a high response rate, a 3-yr rate of PFS of 85%, and a high rate of MRD- at EoT. A substantial proportion of pts converted to MRD- after receipt of R-HiDAC, highlighting the efficacy of cytarabine in MCL. There was a high rate of MRD- after induction chemoimmunotherapy (Len-R-CHOP + R-HiDAC) at 1E5 (97%) and at 1E6 (80%), and the latter predicted remission duration. Several pts converted from MRD- to MRD+ at 6-mos post-EOT and eventually relapsed, suggesting that a more prolonged period of maintenance may be beneficial. Finally, MRD at 1E6 at 6 mos following EoT predicted response duration. Disclosures Batlevi: Life Sci, GLG, Juno/Celgene, Seattle Genetics, Kite: Consultancy; Janssen, Novartis, Epizyme, Xynomics, Bayer, Autolus, Roche/Genentech: Research Funding. Dogan:National Cancer Institute: Research Funding; EUSA Pharma: Consultancy; Takeda: Consultancy; Seattle Genetics: Consultancy; Corvus Pharmaceuticals: Consultancy; Physicians Education Resource: Consultancy; Roche: Consultancy, Research Funding; AbbVie: Consultancy. Drullinsky:Novartis: Research Funding; Roche: Research Funding. Gerecitano:Janssen: Current Employment. Hamlin:Portola Pharmaceutics: Consultancy; J & J Pharmaceuticals: Research Funding; Juno Therapeutics: Consultancy; Celgene: Consultancy; Incyte: Research Funding; Molecular Templates: Research Funding; Portola: Research Funding; Karyopharm: Consultancy. Ho:Invivoscribe, Inc.: Honoraria. Jacob:Adaptive Biotechnologies: Current Employment, Current equity holder in publicly-traded company. Matasar:Rocket Medical: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Daiichi Sankyo: Consultancy; Takeda: Consultancy, Honoraria; GlaxoSmithKline: Honoraria, Research Funding; IGM Biosciences: Research Funding; Janssen: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; Immunovaccine Technologies: Honoraria, Research Funding; Merck: Consultancy; Bayer: Consultancy, Honoraria, Research Funding; Juno Therapeutics: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Teva: Consultancy; Genentech, Inc.: Consultancy, Honoraria, Research Funding. Moskowitz:Incyte: Research Funding; Imbrium Therapeutics, L.P.: Consultancy; Seattle Genetics: Consultancy; Miragen Therapeutics: Consultancy; Merck: Consultancy; Seattle Genetics: Research Funding; Bristol-Myers Squibb: Research Funding; Merck: Research Funding. Mullins:Adaptive Biotechnologies: Current Employment, Other: shareholder. Straus:Elsevier: Membership on an entity's Board of Directors or advisory committees, Other: CME writer; NY Lymphoma Rounds: Consultancy; Imedex, Inc.: Speakers Bureau; Karyopharm Therapeutics: Membership on an entity's Board of Directors or advisory committees; Targeted Oncology: Consultancy, Speakers Bureau; ASH: Other: Conference in December 2019 on HL to other physicians during ASH; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees; OncLive: Speakers Bureau; Takeda Pharmaceuticals: Research Funding, Speakers Bureau. Younes:BioPath: Consultancy; Daiichi Sankyo: Consultancy; Takeda: Consultancy; Novartis: Consultancy; AstraZeneca: Current Employment; BMS: Consultancy; Curis: Consultancy; Epizyme: Consultancy; HCM: Consultancy; Janssen: Consultancy. Zelenetz:Amgen: Consultancy; Celgene: Research Funding; Genentech/Roche: Consultancy; Sandoz: Research Funding; Novartis: Consultancy; Janssen: Consultancy; Adaptive Biotechnology: Consultancy; Celgene: Consultancy; Gilead: Consultancy; BeiGene: Membership on an entity's Board of Directors or advisory committees; Gilead: Research Funding; MorphoSys: Research Funding; MEI Pharma: Research Funding; Roche: Research Funding. Kumar:Celgene: Honoraria, Other: Honoraria for Advisory Board; Astra Zeneca: Honoraria, Other: Honoraria for Advisory Board; Celgene: Research Funding; Pharmacyclics: Research Funding; Adaptive Biotechnologies,: Research Funding; AbbVie: Research Funding; Seattle Genetics: Research Funding; Kite Pharmaceuticals: Honoraria, Other: Honoraria for Advisory Board.

Abstract: Background: Activating mutations of NRAS and KRAS genes are common in newly diagnosed acute myeloid leukemia (AML), occurring in 11-16% and 4-5% of patients, respectively. RAS mutations are frequently acquired at time of progression from MDS to AML and are associated with poor survival. Next generation sequencing (NGS) at diagnosis and during complete remission has shown that RAS mutations have high clearance rates with induction chemotherapy. In the CALGB 8525 study, RAS-mutant younger patients (age & lt;60 years) randomized to treatment with high-dose cytarabine consolidation had a lower 10-year cumulative incidence of relapse when compared to RAS WT patients. We performed a single center retrospective study to determine the outcomes of NRAS and KRAS mutated AML in patients receiving induction chemotherapy. Methods: We retrospectively reviewed the charts of patients with newly diagnosed AML treated at Memorial Sloan Kettering Cancer Center between January 1, 2014 to May 15, 2019. Patients with pathologic confirmation of AML and treatment with induction chemotherapy were included. Age & lt; 18 years old, treatment with a pediatric induction regimen, a diagnosis of biphenotypic AML, unknown RAS mutation status at diagnosis, or treatment an outside institution were criteria for exclusion. All patients underwent NGS from a diagnostic bone marrow aspirate (BMA) with MiSeq or MSK-IMPACT platforms. Mutations present with a variant allele frequency (VAF) ≥ 1% were retained. Response was evaluated per ELN 2017 criteria. Immunophenotypic MRD was identified in BMA by multiparameter flow cytometry. Any level of residual disease was considered MRD+. Baseline characteristics were evaluated by Fisher's exact test and Wilcoxon rank sum tests. Kaplan-Meier estimates were used to summarize OS and EFS. Multivariable cox regression, including time-dependent variables was performed on univariate factors with p & lt;0.05. Results: 202 patients, including 162 WT and 40 RAS mutant met inclusion criteria for further analysis. Mutations in NRAS and KRAS occurred in 14%, and 8% of patients, respectively with 6 patients having co-occurring NRAS and KRAS mutations. At baseline, the RAS mutant AML cohort had a significantly greater proportion of patients with AML-MRC and a trend toward fewer patients receiving allogeneic stem cell transplant. (Table 1.) Cytogenetic abnormalities were similar among RAS and WT patients. Sequencing at diagnosis revealed an increased frequency of FLT3 TKD, RUNX1, TET2, WT1, and ETV6 mutations and a decreased frequency of FLT3-ITD and TP53 mutations in the RAS mutant cohort. Response rates and MRD negative remission rates to induction chemotherapy were similar between RAS and WT AML patients (Table 2). With a median follow up of 25 months among survivors, RAS mutant AML was associated with a significant decrease in median EFS (4.9 vs. 11.4 months, p & lt; 0.01) and a near significant decrease in median OS (12 vs. 30.1 months, p=0.057) (Figure 1 and 2). After controlling for variables with p & lt;0.05 on univariate analysis including age, prior myeloid malignancy, AML classification, ELN risk, transplantation, and re-induction, RAS mutation was independently associated with an increased risk of death (HR 1.85, p=0.016) and decreased EFS (HR 2.19, p & lt; 0.01) on multivariate analyses (Tables 3 and 4). Among 77 patients with paired sequencing at diagnosis and at time of CR or CRi, all RAS mutations (n=17) were cleared (Figure 3). Additionally, other RAS pathway mutations had high clearance rates including PTPN11 (n=8, 100%), NF1 (n=3, 100%, and CBL (n= 4, 80%) (Figure 3). RAS mutation clearance also occurred in 3 out of 8 patients (38%) not achieving CR or CRi after induction. RAS mutation clearance persisted in 6 out of 10 responding patients at time of relapse. Conclusions: In summary, the presence of RAS mutations in patients with AML receiving induction chemotherapy was associated with decreased overall and event free survival. RAS mutant AML was enriched among patients with AML-MRC and prior myeloid neoplasms, which was also associated with decreased survival. Lastly, treatment with chemotherapy led to a high rate of RAS mutation clearance in responders that persisted at the time of disease relapse. The poor prognosis of RAS mutant AML despite RAS mutation clearance suggests that other therapies are needed in combination with chemotherapy to improve outcomes in this high-risk population. Disclosures Cai: Imago Biosciences, Inc.: Consultancy. Viny:Hematology News: Membership on an entity's Board of Directors or advisory committees; Mission Bio: Other: Sponsored travel. Goldberg:American Society of Clinical Oncology: Research Funding; Abbvie: Research Funding; ADC Therapeutics: Research Funding; American Society of Hematology: Research Funding; DAVA Oncology: Honoraria; Pfizer: Research Funding; Arog Pharmaceuticals: Research Funding; Abbvie: Consultancy; Daiichi-Sankyo: Consultancy, Research Funding; Celgene: Consultancy. Tallman:BioLineRx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Biosight: Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Rigel: Consultancy; Cellerant: Research Funding; ADC Therapeutics: Research Funding; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; KAHR: 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. Stein:Astellas Pharma US, Inc: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo, Inc.: Membership on an entity's Board of Directors or advisory committees; Bioline: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees.

Abstract: Measurable residual disease (MRD) is a powerful prognostic factor in acute myeloid leukemia (AML). However, pre‐treatment molecular predictors of immunophenotypic MRD clearance remain unclear. We analyzed a dataset of 211 patients with pre‐treatment next‐generation sequencing who received induction chemotherapy and had MRD assessed by serial immunophenotypic monitoring after induction, subsequent therapy, and allogeneic stem cell transplant (allo‐SCT). Induction chemotherapy led to MRD− remission, MRD+ remission, and persistent disease in 35%, 27%, and 38% of patients, respectively. With subsequent therapy, 34% of patients with MRD+ and 26% of patients with persistent disease converted to MRD‐. Mutations in CEBPA, NRAS , KRAS , and NPM1 predicted high rates of MRD− remission, while mutations in TP53, SF3B1, ASXL1 , and RUNX1 and karyotypic abnormalities including inv (3), monosomy 5 or 7 predicted low rates of MRD− remission. Patients with fewer individual clones were more likely to achieve MRD− remission. Among 132 patients who underwent allo‐SCT, outcomes were favorable whether patients achieved early MRD− after induction or later MRD− after subsequent therapy prior to allo‐SCT. As MRD conversion with chemotherapy prior to allo‐SCT is rarely achieved in patients with specific baseline mutational patterns and high clone numbers, upfront inclusion of these patients into clinical trials should be considered.

Abstract: Background: Measurable residual disease (MRD) is a powerful prognostic factor in AML, including in prediction of outcomes post allogeneic stem cell transplant (alloSCT). However, genomic predictors of successful MRD eradication with chemotherapy prior to alloSCT are unclear. Objectives: Here we provide an integrated analysis of 233 patients (pts) who underwent induction chemotherapy with baseline next-generation sequencing (NGS) followed by serial immunophenotypic monitoring for MRD while patients received additional therapy and alloSCT. Methods: All pts who received anthracycline + cytarabine, +/- investigational agents at Memorial Sloan Kettering Cancer Center starting in April 2014 were retrospectively studied (A). 142 out of 233 pts subsequently underwent alloSCT after induction or additional therapy (A). Immunophenotypic MRD was identified in bone marrow aspirates (BMA) by multiparameter flow cytometry. Any level of residual disease was considered MRD+. Molecular analysis was obtained from pre-induction BMA by NGS using 28 or 49 or 400 gene panels. Results: Patient and treatment characteristics for all pts are detailed in panel (B). Induction chemotherapy resulted in an MRD-CR/CRi and MRD+CR/CRi in 29% and 23% of all pts, respectively (C). Additional therapy included consolidation (n=51), intensive re-induction/salvage (n=47) and non-intensive therapy (n=9). Of 83 AML pts with persistent AML and 58 pts with MRD+CR/CRi after induction (R1), 38/141 (27%) were able to be converted to MRD-CR/CRi. While 33/38 of pts went on to alloSCT after conversion to MRD-CR/CRi, 22 and 36 pts went to alloSCT with persistent AML and MRD+CR/CRi AML, respectively. We focused on pre-induction molecular predictors for achieving an MRD-CR/CRi response prior to transplant for the 142 pts who underwent alloSCT (D). Pts with a NPM1 (79%, Odds ratio [OR] 3.7, p=0.01), IDH1 (92%, OR 3.9, p=0.01) and KRAS (100%, OR 5.0, p=0.03) mutations achieved high rates of MRD-CR/CRi prior to alloSCT. In contrast, RUNX1 (28%, OR 0.2, p=0.01), TP53 (12%, OR 0.1, p=0.02) and SF3B1 (14%, OR 0.1, p=0.04) mutations predicted decreased odds of achieving MRD-CR/CRi prior to alloSCT despite induction and post-induction therapy. AlloSCT resulted in high rates of conversion from MRD+ and persistent disease to MRD negativity. Most pts who entered transplant with CR/CRi MRD+ (28/36, 76%) or persistent AML (14/22, 64%) cleared MRD by the first post-transplant BMA at a median of 32 days (E). Post-alloSCT follow-up indicated value in converting MRD+ to MRD- prior to alloSCT. There was no significant difference in post-transplant cumulative incidence of relapse (F) and OS (G) between early MRD-CR/CRi immediately following induction versus later conversion to MRD-CR/CRi with additional therapy prior to alloSCT. Despite initial post-transplant MRD clearance, pts who entered alloSCT with persistent AML or MRD+ had higher incidence of relapse (p=0.00037, F) and poorer post-transplant OS (p=0.013, G) compared to pts who entered alloSCT with MRD-. Pts with persistent disease prior to alloSCT had shorter duration of MRD- induced by alloSCT compared to pts with MRD-CR/CRi after induction or converted MRD-CR/CRi prior to alloSCT (p=0.0042, H). Importantly, duration of MRD negativity after alloSCT for patients who achieved MRD- prior to alloSCT was not affected by whether patients received induction +/- consolidation (I: treatment type 1-3 from B) vs. induction and salvage treatment for refractory AML (I: treatment type 4-6 from B). Conclusion: We show that transplanted AML pts with specific molecular mutations (RUNX1, SF3B1, and TP53) are unlikely to achieve MRD-CR/CRi after induction, consolidation or salvage therapy, while other mutations (NPM1, IDH1, KRAS) predict high rates of MRD- prior to alloSCT. Additional post-induction therapy may be advantageous for some MRD+ pts to achieve MRD- prior to alloSCT. Post-transplant OS is improved in pts who are MRD- at time of transplant, regardless of whether they required additional therapy beyond induction to achieve this state. AlloSCT is highly effective at eradicating MRD, but post-transplant MRD- is more durable in pts who are MRD- pre-alloSCT. Our results suggest that development of MRD-eradicating therapies has the potential to improve post-transplant outcomes and argues for innovative trials for pts with adverse molecular features currently unlikely to achieve MRD- pre alloSCT. Figure Disclosures Cai: Imago Biosciences, Inc.: Consultancy, Current equity holder in private company; DAVA Oncology: Honoraria. Geyer:Amgen: Research Funding. Glass:Gerson Lehman Group: Consultancy. Stein:Syros: Membership on an entity's Board of Directors or advisory committees; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biotheryx: Consultancy; Bayer: Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Syndax: Consultancy, Research Funding; Seattle Genetics: Consultancy; Abbvie: Consultancy; Amgen: Consultancy; Celgene Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas Pharmaceuticals: 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, Research Funding. Levine:Gilead: Honoraria; Isoplexis: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Qiagen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy; Lilly: Consultancy, Honoraria; Imago: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy; Novartis: Consultancy; Prelude Therapeutics: Research Funding; Loxo: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Morphosys: Consultancy; Roche: Consultancy, Honoraria, Research Funding. Gyurkocza:Actinium: Research Funding. Perales:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Nektar Therapeutics: 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; MolMed: Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Medigene: Membership on an entity's Board of Directors or advisory committees, Other; Servier: Membership on an entity's Board of Directors or advisory committees, Other; Omeros: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Consultancy, Honoraria; NexImmune: Membership on an entity's Board of Directors or advisory committees; Cidara Therapeutics: Other; Miltenyi Biotec: Research Funding; Kite/Gilead: Honoraria, Research Funding; Incyte Corporation: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria; Bellicum: Honoraria, Membership on an entity's Board of Directors or advisory committees. Abdel-Wahab:H3 Biomedicine Inc.: Consultancy, Research Funding; Janssen: Consultancy; Envisagenics Inc.: Current equity holder in private company; Merck: Consultancy. Papaemmanuil:Kyowa Hakko Kirin: Consultancy, Honoraria; Isabl: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; MSKCC: Patents & Royalties; Novartis: Consultancy, Honoraria; Illumina: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Prime Oncology: Consultancy, Honoraria. Giralt:KITE: Consultancy; NOVARTIS: Consultancy, Honoraria, Research Funding; OMEROS: Consultancy, Honoraria; AMGEN: Consultancy, Research Funding; TAKEDA: Research Funding; ACTINUUM: Consultancy, Research Funding; MILTENYI: Consultancy, Research Funding; CELGENE: Consultancy, Honoraria, Research Funding; JAZZ: Consultancy, Honoraria. Tallman:Glycomimetics: Research Funding; Rafael: Research Funding; Amgen: Research Funding; Bioline rx: Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; KAHR: Membership on an entity's Board of Directors or advisory committees; UpToDate: Patents & Royalties; Rigel: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Oncolyze: Membership on an entity's Board of Directors or advisory committees; Delta Fly Pharma: Membership on an entity's Board of Directors or advisory committees; BioSight: Membership on an entity's Board of Directors or advisory committees, Research Funding; ADC Therapeutics: Research Funding; Orsenix: Research Funding; Cellerant: Research Funding; Abbvie: Research Funding. Goldberg:AROG: Research Funding; Aprea: Research Funding; ADC Therapeutics: Research Funding; Genentech: 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, Research Funding; Celgene: Consultancy; Aptose: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Dava Oncology: Honoraria; Pfizer: Research Funding; Celularity: Research Funding.

Abstract: Background: MRD is a powerful prognostic factor in AML. Emerging data indicate that allogeneic stem cell transplant (alloSCT) with MRD results in outcomes equivalently poor to alloSCT with morphologic AML (Araki et al., JCO 2016). Genomic predictors of MRD are unclear, and relative efficacy of therapies for MRD remains elusive. Objectives: Here we provide an integrated analysis of responses for 163 patients (pts) who underwent induction chemotherapy with baseline next-generation sequencing (NGS) followed by serial immunophenotypic monitoring for MRD. Methods:163 patients starting in April 2014 who underwent induction chemotherapy at Memorial Sloan Kettering Cancer Center were retrospectively studied. All received anthracycline + cytarabine, with or without investigational agents. Immunophenotypic MRD was identified in bone marrow aspirates (BMA) by multiparameter flow cytometry. Any level of residual disease was considered MRD+. Molecular analysis was obtained from pre-induction BMA by NGS using 28 or 49 gene panels. Cytogenetics/FISH were performed using standard techniques. Results: Patient characteristics are in Table 1. 7/163 (4.9%) died within 30 days of induction.153 pts had BM biopsy after induction prior to further therapy. 124/153 underwent flow after induction. 65/124 (52.4%) achieved CR/CRi after induction alone, 31/124 (25%) MRD+CR/CRi, and 34/124 (27.4%) MRD-CR/CRi. Pre-induction molecular analysis from 126 suggests that certain cytogenetic and molecular abnormalities correlate with achievement of MRD-CR. (Figure 1) Only 2/25 (8%) with RUNX1, 0/13 with SF3B1, and 0/11 with TP53 mutations achieved MRD-CR/CRi as best response after 1 cycle of induction. Only 3 additional RUNX1, 2 SF3B1, and 0/11 TP53 achieved MRD-CR/CRi as best response after a second cycle of therapy. In contrast, 7/8 with CBF AML (inv16 and no KIT mutation, n=4) or (t(8;21), n=3) achieved MRD-CR/CRi (n=5) or CR without flow (n=2) after 1 cycle of induction. 91/163 (55.8%) underwent alloSCT following induction or additional therapy. Post-alloSCT follow-up indicates potential value in converting MRD+ to MRD-. 84/91 were evaluable for MRD with flow cytometry prior to alloSCT. 41/84 (48.8%) were MRD-, 30/84 (35.7%) MRD+, and 13/84 (15.4%) persistent AML. 13/41 (31.7%) MRD-pre-alloSCT were MRD- post-induction. 28/41 (68.2%) MRD+ or persistent AML converted to MRD- prior to alloSCT following additional therapy. 23/29 MRD+CR/CRi pts after induction were intermediate/unfavorable and therefore transplant candidates. 19/23 MRD+CR/CRi intermediate/unfavorable underwent transplant (9 without post-induction therapy, 10 after consolidation), while 4 did not proceed to transplant due to relapse after induction (n=1), relapse after consolidation (n=2), and patient preference. There was no significant difference in post-transplant OS between early MRD-CR immediately following induction and later conversion to MRD-CR prior to alloSCT (Figure 1B). Post-transplant analysis reveals that most pts who enter transplant with persistent AML (n=13) or MRD+ (n=30) clear MRD (30/43, 69.7%) by the first post-transplant BM (median 32 days, Figure 1C). Despite initial post-transplant MRD clearance, pts who entered alloSCT with persistent AML or MRD+ had poorer post-transplant OS compared to pts who entered alloSCT with MRD- (p=0.02, Figure 1D). Conclusion: Our data show that AML pts with specific molecular mutations (RUNX1, SF3B1, and TP53) are unlikely to achieve MRD-CR/CRi after induction chemotherapy. We further show that additional therapy such as consolidation may be advantageous for some MRD+ pts to achieve MRD-CR prior to alloSCT, although others remain resistant to MRD clearance. Post-transplant OS is improved in pts who are MRD- at time of transplant, regardless of whether they required additional therapy beyond induction to achieve this state. Our results suggest that development of MRD-eradicating therapies after AML induction has the potential to improve post-transplant outcomes. Disclosures Goldberg: AROG: Research Funding; Pfizer: Research Funding; Celgene: Consultancy. Arcila:Invivoscribe, Inc.: Consultancy, Honoraria. Perales:Takeda: Other: Personal fees; Merck: Other: Personal fees; Abbvie: Other: Personal fees; Incyte: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees and Clinical trial support; Novartis: Other: Personal fees. Tallman:ADC Therapeutics: Research Funding; Daiichi-Sankyo: Other: Advisory board; Orsenix: Other: Advisory board; Cellerant: Research Funding; BioSight: Other: Advisory board; AROG: Research Funding; AbbVie: Research Funding.

Abstract: Background Measurable residual disease (MRD) is associated with inferior outcomes in patients with acute myeloid leukemia (AML). MRD monitoring enhances risk stratification and may guide therapeutic intervention. Post-induction MRD is frequently cleared with further therapy and the clearance may lead to better outcomes. In contrast, persistent MRD is associated with poor outcomes. At present it is not possible to predict which patients are likely to clear MRD with further therapy. Here we report a simple, objective, widely applicable and quantitative MFC approach using the ratio of blast/PDC to predict persistent MRD and poor outcomes in AML. Patients and Methods A cohort of 136 adult patients with a confirmed diagnosis of AML by WHO criteria who underwent standard induction therapy at a single center between 4/2014 and 9/2017 was initially included. 69 patients achieved complete morphologic remission (36 MRD-neg. and 33 MRD-pos.). MRD status was assessed by MFC using a different from normal (DfN) approach. PDC were quantified as the percent of total WBC by flow cytometry based on low side scatter, moderate CD45, CD303, bright CD123 and HLA-DR expression. Results The proportion of PDC was markedly decreased in patients with AML (≥20% blasts) (N=136) with a median of 0.016% (interquartile range IQR: 0.0019%-0.071%, Figure 1A), more than 10-fold lower than observed in normal controls (median 0.23%, IQR 0.17%-0.34%) (N=20). While there was no difference between MRD-neg. and normal control groups (median 0.31%, IQR: 0.17%-0.49%; vs. 0.28%, IQR: 0.17%-0.34%), MRD-pos. group had significantly reduced PDC proportion compared to the control (median 0.074%, IQR: 0.022%-0.33%, Wilcoxon rank sum, p=0.019). In an attempt to achieve better separation and to eliminate possible effects of hemodilution, the ratio of blast/PDC was calculated by using the proportions of blasts and PDCs out of total WBCs as quantitated by flow cytometry. A cut-off threshold of the blast/PDC ratio of 10 was chosen to separate each group (Figure 1B). Importantly, a ratio cut-off of 10 had a corresponding specificity of 97.4% for predicting MRD positivity status. MRD positivity was significantly associated with inferior overall survival (OS) and relapse-free survival (RFS) in our study cohort (OS HR 4.11 (95% CI: 1.30-13.03), p=0.016; RFS HR 4.20 (95% CI: 1.49-11.82), p=0.007, Figure 1C and D). The 2-year cumulative incidence of relapse in the MRD-neg. group compared to MRD-pos. group was 10% (95% CI: 2-24%) vs. 37% (95% CI: 18-56%, p=0.014). Importantly, blast/PDC ratio ≥10 was also strongly associated with inferior OS and RFS (OS HR 3.12 (95% CI: 1.13-8.60), p= 0.028; RFS HR 4.05 (95% CI: 1.63-10.11), p=0.003, Figure 1E and F), which is similar in magnitude to MRD positivity. Furthermore, MRD-pos. patients with blast/PDC ratio 〈 10 had 4 times higher MRD clearance rate than MRD-pos. patients with a ratio ≥10 (6/11, 55% vs 2/17, 12%, Fisher exactp=0.02). Conclusion We have established an objective and quantitative MFC method to risk stratify post induction AML patients by risk for relapse, MRD clearance and likelihood of survival. Loss of PDC correlates with residual leukemia, is highly specific for MRD positivity in post-induction patients, and strongly predicts poorer overall survival and higher likelihood of relapse. Loss of PDC also predicts persistent MRD in post-induction MRD-pos. patients despite further therapy, suggesting that MRD-pos. patients with normal PDC may benefit from further therapy prior to transplant, while MRD-pos. patients with loss of PDC may not. Figure 1. Figure 1. Disclosures Goldberg: AROG: Research Funding; Pfizer: Research Funding; Celgene: Consultancy. Geyer:Dava Oncology: Honoraria. Levine:Isoplexis: Equity Ownership; C4 Therapeutics: Equity Ownership; Gilead: Honoraria; Qiagen: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Prelude: Research Funding; Imago: Equity Ownership; Roche: Consultancy, Research Funding; Loxo: Consultancy, Equity Ownership; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Epizyme: Patents & Royalties; Janssen: Consultancy, Honoraria. Tallman:BioSight: Other: Advisory board; AROG: Research Funding; AbbVie: Research Funding; Cellerant: Research Funding; ADC Therapeutics: Research Funding; Orsenix: Other: Advisory board; Daiichi-Sankyo: Other: Advisory board.