Equity Holder Research Articles

Quality of Life and Life Satisfaction in AML Long-Term Survivors: Primary Results of the AMLCG-Survivorship Study

IntroductionAn increasing proportion of patients with Acute Myeloid Leukemia (AML) become long-term survivors. Somatic and psycho-social outcomes are therefore becoming increasingly important, but little is known about the long-term effects of the disease and its treatment.MethodsWe designed a comprehensive analysis of AML survivorship outcomes including psycho-social well-being and somatic health status and conducted a questionnaire-based study collecting data from AML long term survivors (AML-LTS) and their physicians. This report focuses on overall and health-related quality of life. Somatic, especially cardiovascular, morbidity in AML-LTS are reported separately (Moret et al.). The primary aim of this study was to compare quality of life (QoL, measured by the FACT-G questionnaire) and general and health-related life satisfaction (gLS/hLS, measured by the FLZ-M questionnaire) of AML-LTS with normative data of German adults who were not diagnosed with AML (Holzner et al. 2009; Daig et al. 2009). FLZ-M and FACT-G scores were standardized relative to the normal population mean and standard deviation, stratified by sex and age. These z-scores were then tested against the fixed value 0 (indicating no difference between AML-LTS and the general population) using Mann-Whitney U-tests. Our statistical design incorporated a sequentially rejective testing procedure to maintain the multiple testing significance level at 5%, using a graphical model as described by Bretz et al. (2009).Results427 former AML patients who had been enrolled in AMLCG trials (AMLCG-1999, AMLCG-2004, AMLCG-2008) or the AMLCG patient registry, participated in this study between 5 and 18.6 years [y] after their initial AML diagnosis (median, 11.3y). Median age of AML-LTS was 61y (range 28y-93y), and 56% were female. Thirty-eight percent of participants had been treated with chemotherapy alone, while 62% received at least one allogeneic stem cell transplant (alloSCT). A relapse occurred in 24% of the participants.Unexpectedly, quality of life and general life satisfaction summary scores were significantly higher in AML-LTS (p<.001) compared to adults without the diagnosis of AML, although most differences on QoL subscales relative to the general population were small and very likely not clinically relevant. No statistical difference between AML-LTS and normal adults was found for health-related life satisfaction (hLS).Notably, a subgroup of participants (26%) reported poor physical well-being (PWB), indicated by a FACT PWB subscore more than one standard deviation (SD) below the age- and sex-matched general population value (Figure A). This resulted in poor overall QoL (i.e. >1 SD below normal) for 13% of the participants (Figure B).To identify factors potentially associated with poor overall QoL, we constructed a logistic regression model including pre-specified cofactors (age, sex, time since initial diagnosis, relapse and alloSCT) and additional covariables that associated with QoL in univariate analyses (Table C). We found that participants with younger age, male sex, lower educational level, shorter time since diagnosis and a altered financial situation reported significantly lower QoL. No influence was found for other characteristics including treatment (alloSCT vs. no alloSCT), previous relapse, or de novo vs. secondary or therapy-related AML.DiscussionUnlike previous studies of AML survivorship, our large cohort included a diverse spectrum of patients regarding age, time since diagnosis, and treatment modalities, which allows for new insight into long-term quality of life. Our study establishes that overall QoL in AML long-term survivors is comparable to the general population. Improvement of QoL continues beyond five years post diagnosis. Importantly, disease- and treatment-related factors, such as prior relapse or status post allogeneic transplantation, are not associated with overall QoL. However, we were able to identify risk factors for worse QoL (younger age, male sex, alteration of the financial situation), delineating a subgroup of patients that may still have a need for targeted psycho-social interventions five or more years after an AML diagnosis. [Display omitted] DisclosuresBerdel: Philogen S.p.A.: Consultancy, Current equity holder in publicly-traded company, Honoraria, Membership on an entity's Board of Directors or advisory committees. Hiddemann: Janssen: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding. Metzeler: AbbVie: Honoraria; Astellas: Honoraria; Daiichi Sankyo: Honoraria; Novartis: Consultancy; Jazz Pharmaceuticals: Consultancy; Pfizer: Consultancy; Celgene/BMS: Consultancy, Honoraria, Research Funding.

Therapeutic Targeting of CD74 with STRO-001 Antibody-Drug Conjugate in AML and ALL

Introduction: Despite advances in cytotoxic and targeted therapies, recurrent disease remains the most significant obstacle to long-term survival in patients with childhood and adult leukemias. As part of our efforts to identify therapies that can be repurposed for immediate use in patients with leukemia, we interrogated a library of all available antibody-drug conjugates (ADCs) whose targets are expressed in leukemias (AML or ALL). A list of targets with available ADCs was merged with transcriptome data from over 3000 pediatric and adult leukemias (AML and ALL) to identify targets that are expressed in a large cohort of leukemias with immediate therapies for repurposing. The transcriptome data set included nearly 2000 pediatric AML cases sequenced as part of Target Pediatric AML (TpAML), 419 adult AML cases from TCGA LAML and the Beat AML program, as well as 853 ALL cases from COG and St. Jude trials. In this repurposing endeavor, CD74 emerged as the most expressed transcript in AML and ALL. CD74 encodes for a cell surface protein that associates with the class II major histocompatibility complex and is involved in the regulation of antigen presentation for immune response and B-cell differentiation. STRO-001 (Sutro Biopharma) is a CD74-directed, site-specific ADC developed for the treatment of multiple myeloma and lymphomas. Given broad expression of CD74 in leukemias, we evaluated the efficacy of STRO-001 in AML and ALL preclinical models.Methods: To characterize CD74 expression, RNA-seq data obtained from pediatric and adult AML and ALL patients was examined. Cell surface expression of CD74 was determined by flow cytometry using PE labeled anti-human CD74 antibody. The CD74-targeting ADC (STRO-001) was obtained from Sutro Biopharma.The preclinical efficacy of STRO-001 was evaluated against AML and ALL cell lines and patient samples expressing various levels of CD74 in vitro and in vivo. For in vivo studies, AML and ALL cell lines were transduced with GFP/Luciferase construct, and GFP+ cells were injected intravenously into NSG mice. Leukemia burden was measured by bioluminescence (IVIS) imaging weekly.Results: Transcriptomics analysis showed CD74 expression in a majority of adult and pediatric AML (>99% of cases) and at a much higher level compared CD33 and CD123 (targets currently developed for AML, Fig. 1A). CD74 is also broadly expressed in pediatric ALL, with a significant increase in expression observed compared to CD19 and CD22 (known targets in ALL, Fig. 1B). We confirmed that CD74 is expressed on the cell surface of AML blasts in primary patient samples (Fig. 1C) as well as AML and ALL cell lines (Fig. 1D). Given confirmation of cell surface expression of CD74, we investigated whether targeting CD74 can effectively eliminate leukemia cells. We evaluated the in vitro cytotoxicity of STRO-001 against K562 (a CML cell line that does not express CD74), AML cell lines (MV4;11 and NOMO-1), and ALL cell lines (REH1 and RS4;11) with varied CD74 expression. STRO-001 demonstrates target-specific cytotoxicity against CD74-expressing AML and ALL cell lines, but not K562 cells (Fig. 1E). STRO-001 exhibited high potency in CD74 expressing cells, with IC-50s of 41nM (MV4;11), 1.3nM (NOMO-1), 0.7nM (REH-1) and 3nM (RS4;11). In vivo studies in NSG mice transplanted with AML and ALL cell lines showed high potency. Treatment with STRO-001 at 3mg/kg once a week for 3 weeks effectively eradicated the leukemia in NOMO-1, REH-1, and RS4;11-bearing xenograft mice, while disease progression was observed in untreated control mice (Fig. 1F). We further evaluated the efficacy of STRO-001 in primary patient samples. Primary leukemia specimens from 3 patients with varied CD74 expression (Fig. 1G) were incubated with increasing concentrations of STRO-001 for 3 days. STRO-001 exhibited potent anti-leukemia activity against primary AML cells with IC-50s of 17.4nM, 12.8nM, and 4.07nM, respectively (Fig. 1H).Conclusion: Through transcriptomics profiling and validation of the cell surface expression by flow cytometry, we have identified CD74 as a viable therapeutic target for AML and ALL in children and adults. We further demonstrate that targeting CD74 with STRO-001 effectively eliminates leukemia cells both in vitro and in vivo, providing the preclinical data to compel evaluation of STRO-001 in clinical trials for childhood and adult leukemia. [Display omitted] DisclosuresHylkema: Moderna: Current equity holder in publicly-traded company; Quest Diagnostics Inc: Current equity holder in publicly-traded company. Pardo: Hematologics, Inc.: Current Employment. Abrahams: Sutro Biopharma: Current Employment. Bedard: Sutro Biopharma: Current Employment. Molina: Sutro Biopharma: Current Employment. Eidenschink Brodersen: Hematologics, Inc.: Current Employment, Other: Equity Ownership. Loken: Hematologics, Inc.: Current Employment, Other: current equity holder in a privately owned company.

FOXO1 Dependent Transcription Network Is a Targetable Vulnerability of Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) often has an adverse prognosis and despite aggressive multimodal treatment with conventional and targeted therapies, the median survival of MCL patients remains approximately 4 years. Thus, there is a significant unmet need to find novel targets and rational combination treatments.Targeting lineage vulnerabilities driven by specific transcription factors has been broadly confirmed as an effective intervention in many human cancers. To identify the transcription program dependency of MCL cells, we conducted an unbiased domain-focused CRISPR-Cas9 screening against a library of 8,750 sgRNAs targeting 1,434 transcription factors in MCL cell lines (JEKO1, MAVER1, UPN1, and CCMCL1). We identified Forkhead Box O1 (FOXO1), EBF1, PAX5, and IRF4 as 4 transcription factors that are specifically required for MCL survival and growth. Chromatin-immunoprecipitation and sequencing (ChIP-Seq) analysis further revealed that the four transcription factors act together to orchestrate B cell lineage transcriptional program and MCL cell survival.Despite its well-recognized role as a tumor suppressor, FOXO1 has been implicated as a lineage specific transcription factor involved in mature B cell development. Genetic studies revealed a critical role of FOXO1 in germinal center dark zone formation and lymphomagenesis, raising the possibility that FOXO1 acts as a master transcription factor for lineage survival transcription program of MCL. Indeed, hierarchical interaction analysis revealed that FOXO1 functions as a pioneer factor that facilitate the chromatin access of other B cell lineage transcription factors. We demonstrated that interaction of FOXO1 to its cognate motif stabilizes B cell transcription factor complex and supports MCL progression. Along this line, we show that enforced expression of FOXO1 in myeloid leukemia cells induces transdifferentiation and B-cell specific gene expression. Mechanistically, we demonstrate through tiling CRISPR scanning screen that forkhead DNA binding and c-terminal transactivation domains of FOXO1 are specifically required for the viability of MCL cells.Given our finding of FOXO1 as a lineage-specific oncogene in MCL, we next explored the possibility of developing FOXO1-tageted inhibitors. We screened a library of potential small molecule inhibitors of FOXO1 (Forkhead BioTherapeutics) and identified cpd10 as one of the most potent and selective FOXO1 inhibitors (IC 50=76 ×/÷ 1.7. nM) Through the CCMCL1 MCL-NSG preclinical model, we found that cpd10 (100 mg/kg/daily) was well tolerated without overt toxicities. Importantly, prolonged treatment induced a robust cytotoxic response of MCL cells and suppressed MCL progression in vivo. Altogether, our findings identified FOXO1 as a MCL lineage-survival oncogene that can be exploited as a therapeutic target of future drug development. DisclosuresCantley: Petra Pharmaceuticals: Research Funding; Agios Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Elemento: Freenome: Consultancy, Other: Current equity holder in a privately-held company; Volastra Therapeutics: Consultancy, Other: Current equity holder, Research Funding; Champions Oncology: Consultancy; Janssen: Research Funding; Owkin: Consultancy, Other: Current equity holder; AstraZeneca: Research Funding; One Three Biotech: Consultancy, Other: Current equity holder; Eli Lilly: Research Funding; Johnson and Johnson: Research Funding. Baiocchi: Prelude Therapeutics: Consultancy; viracta: Consultancy, Current holder of stock options in a privately-held company; Codiak Biosciences: Research Funding; Atara Biotherapeutics: Consultancy. Belvedere: Forkhead BioTherapeutics: Current Employment. Paik: Forkhead BioTherapeutics: Research Funding.

European Leukemianet (ELN) Response Predicts Disease Progression but Not Thrombosis or Death in Polycythemia Vera (PV): An Analysis of a Multicenter Database

European Leukemianet (ELN) Response Predicts Disease Progression but Not Thrombosis or Death in Polycythemia Vera (PV): An Analysis of a Multicenter Database

An Interim Report on a Phase 1/2 Study of HPN217, a Half-Life Extended Tri-Specific T Cell Activating Construct (TriTAC ®) Targeting B Cell Maturation Antigen for the Treatment of Relapsed/Refractory Multiple Myeloma

An Interim Report on a Phase 1/2 Study of HPN217, a Half-Life Extended Tri-Specific T Cell Activating Construct (TriTAC ®) Targeting B Cell Maturation Antigen for the Treatment of Relapsed/Refractory Multiple Myeloma

Characterizing Naked Nuclei Frequency and Movement in Primary AML Cell Culture Using an ECM-Based Model

INTRODUCTIONNaked nuclei (NN) are observed upon examining bone marrow aspirate slides from healthy individuals and from those with hematologic malignancies, but are not well understood. Without characteristic findings like cytoplasm or plasma membrane, NN are considered remnants of slide preparation or are discounted as cells of undetermined significance. NN have been associated with poor prognosis in several solid cancers. Understanding the significance of NN in hematologic malignancies such as acute myelogenous leukemia (AML) may elucidate valuable diagnostic and prognostic knowledge. Decellularized Wharton's jelly matrix (DWJM) is an extra cellular matrix (ECM)-based in vitro model that shares similar elements with the bone marrow ECM and can be used as scaffolding to culture leukemia cells. We hypothesize that NN exist in AML and interact with other cells, suggesting potential biological relevance within the bone marrow microenvironment.METHODSPrimary AML samples obtained by leukapheresis were cultured in suspension with growth media or in the presence of DWJM submerged in growth media. In samples grown with DWJM, cells that were non-adherent to the matrix were collected first and then adherent cells were isolated by treating DWJM with collagenase. Live cells were stained with CellVue Maroon (CVM) for membrane, CellTracker Green (CTG) for cytoplasm, and Hoechst 33342 for nucleus, followed by analysis with Amnis/Luminex ImageStream-X imaging flow cytometer (Figure 1A). NN were defined as events positive for nuclear stain and negative for cytoplasmic and membrane stains (Figure 1B). 3-D movement of adherent AML cells in DWJM was captured in real time using confocal microscopy. Fixed cells from leukemia cell line K562 served as a control for movement. NN (Hoechst positive only), non-nucleated (Hoechst negative/CTG positive), and nucleated cells (Hoechst and CTG positive) were identified by fluorescent labeling. NN were also observed after isolation by cell sorting. Cell speed, cell displacement from origin, and change in distance to closest neighboring cell over time were measured. Additionally, flow sorted NN were examined by immunohistochemistry (IHC).RESULTSAdherent populations contained significantly more NN than non-adherent and suspension populations. The frequency of NN in matrix adherent cells ranged from 0.4-2.4% at day 3 and 0.5-5.4% at day 7 of culture (Figure 1C). Through confocal microscopic analysis, we observed NN, nucleated, and non-nucleated cells moving at speeds ranging from 0.002-0.08 µm/sec. Fixed cells showed no discernible movement in DWJM. The average speed of NN [0.019 mm/s, SD 0.011] significantly differed from the average speed of nucleated and non-nucleated cells [0.027 mm/s, SD 0.016] (p=0.004) (Figure 1E). To demonstrate directional movement, we measured change in distance between NN and closest neighboring nucleated or non-nucleated cells over time. Cells (nucleated and non-nucleated) and NN moved closer to each other over time suggesting directional movement (p=0.001) (Figure 1D). NN also showed movement in DWJM after isolation by cell sorting. IHC analysis showed sorted NN stained positive for nuclear lamin A/C, which are considered markers of nuclear membrane (Figure 1F).CONCLUSIONSOur findings confirm that NN are present in primary AML cells cultured in vitro using ourECM-based model and that they can be isolated using flow cytometry. Additionally, NN display directional movement in DWJM suggesting that they interact with other cells and may be biologically relevant structures in the bone marrow microenvironment. [Display omitted] DisclosuresBaran: AstraZeneca/Acerta: Research Funding. Chu: Pfizer: Current equity holder in publicly-traded company; Acerta/AstraZeneca: Research Funding; TG Therapeutics: Research Funding.

Evidence of Classical Complement Pathway Involvement in a Subset of Patients with Warm Autoimmune Hemolytic Anemia

Introduction: Autoimmune Hemolytic Anemia (AIHA) is caused by autoantibodies that react with red blood cells (RBCs) resulting in predominantly extravascular hemolysis in an FcR and/or complement-dependent manner. In warm AIHA (wAIHA), autoantibodies are generally of the IgG isotype, while in cold agglutinin disease (CAD) they are predominantly of the IgM isotype. It is well established that the classical complement cascade is critical for the pathogenesis of CAD based on therapeutic clinical studies. Published data also suggest that complement activation plays a role in wAIHA, although it is not clear which patients would most benefit from complement-based therapy. To help address this question, we utilized an assay that measures the ability of autoantibodies in patient sera to induce complement deposition on the surface of donor RBCs (based on Meulenbroek, et al., 2015).Methods: Sera were collected retrospectively from 12 wAIHA patients whose direct antiglobulin tests (DAT) were either IgG+/C3+ or IgG+/C3-. Sera retrospectively collected from two CAD patients were used as positive controls. Individual patient sera were examined in the in vitro complement deposition assay using RBCs from type O+ healthy donors. RBCs and sera were incubated at 37 oC in the presence of either EDTA or an inhibitory antibody against C1q as inhibitors of the classical pathway. RBCs were then stained and processed by flow cytometry to determine the level of C4 deposition.Results: Sera from both CAD patients deposited C4 on the surface of ~70% of healthy human RBCs in vitro. Four out of twelve (33%) sera from wAIHA patients displayed this activity, and all four of these patients were identified as IgG+/C3+ on DAT. Complement deposition ranged from ~10-60% of the RBCs in wAIHA, suggesting heterogeneity in antibody activity for complement deposition in sera from wAIHA patients. Addition of EDTA or an inhibitory antibody against C1q fully blocked deposition of C4 on RBCs by wAIHA sera, indicating dependence of the classical complement pathway. These results indicate differences in the frequency of classical pathway involvement in CAD versus wAIHA and may help identify a subset of wAIHA patients most likely to respond to anti-C1q therapy.Conclusions: The hypothesis of classical complement cascade involvement in wAIHA disease in a subset of patients is supported by our results. Critically, complement deposition on the surface of cells by anti-C1q prevented the deposition of a downstream complement marker, C4. Inhibition of C1q has been shown to block activation of all downstream classical complement components, including C3b and C4b involved in extravascular hemolysis and C5b involved in direct cell lysis. The therapeutic potential of blocking classical complement pathway activity in wAIHA is currently being evaluated in an ongoing Phase 2 interventional trial (NCT04691570) assessing efficacy of an anti-C1q drug candidate in wAIHA patients, focusing on those with evidence of classical complement pathway activity. DisclosuresTeigler: Annexon Inc: Current Employment, Current equity holder in publicly-traded company. Low: Annexon Inc: Current Employment, Current equity holder in publicly-traded company. Rose: Annexon Inc: Current Employment, Current equity holder in publicly-traded company. Cahir-Mcfarland: Annexon Inc: Current Employment, Current equity holder in publicly-traded company. Yednock: Annexon Inc: Current Employment, Current equity holder in publicly-traded company. Kroon: Annexon Inc: Current Employment, Current equity holder in publicly-traded company. Keswani: Annexon Inc: Current Employment, Current equity holder in publicly-traded company. Barcellini: Novartis: Honoraria; Bioverativ: Membership on an entity's Board of Directors or advisory committees; Agios: Honoraria, Research Funding; Alexion Pharmaceuticals: Honoraria; Incyte: Membership on an entity's Board of Directors or advisory committees.

Assessing Romiplostim Dose and Platelet Response-Guided Titration to Support Use of Romiplostim in ITP Patients Less Than 12 Months from Diagnosis

Background: Romiplostim, a subcutaneous treatment for adult ITP, uses a platelet response-guided dose adjustment algorithm (USPI dosing, Table 1) to maintain patients' platelet count (PC). Romiplostim was recently approved for patients with ITP ≤ 12 months from diagnosis.Objectives: The primary objective of this analysis was to confirm the appropriateness of romiplostim dose and platelet response-guided titration for patients with ITP ≤ 12 months from diagnosis using a model based approach.Methods: Data from 268 adult patients with ITP ≤ 12 months from diagnosis was extracted from 7 previously conducted clinical studies and used to develop a model based on a previously published model of romiplostim dose-response in ITP patients (Perez-Ruixo et al, 2012). Following the model update, patient characteristics (time from diagnosis, PC at baseline, sex, age, weight, number of prior therapies, region, and use of rescue medications) were assessed to identify any potential factors influencing dose or platelet response in ITP patients ≤ 12 months from diagnosis. The model was qualified for simulation using standard methods modified to account for response-guided dosing. Additionally, observed and predicted platelet responses (incidence of durable response, sustained response, and duration of response) were compared for patients stratified by time from ITP diagnosis (<3, 3 to ≤ 6, and 6 to ≤ 12 months). Simulations were then conducted using prescribed dosing guidance to predict PC and romiplostim doses over 52 weeks of treatment in patients ≤ 6 months and > 6 to ≤ 12 months from diagnosis.Results: The analysis dataset included 7854 PC from 268 patients (with median baseline PC of 18 x 10 9/L and median time since diagnosis of 3 months) receiving romiplostim weekly for up to 3 years at doses ranging from 1 to 15 mg/kg.The updated model (Figure 1) consisted of a drug-sensitive progenitor cell compartment (Pre), 4 maturation compartments (Transit), and a peripheral blood compartment (Circ). Romiplostim increased production of platelet precursors in Pre in 2 ways: 1. linearly with romiplostim exposure (immediate response), and 2. as a function of cumulative administered dose. Response to romiplostim was bimodal with approximately 50% of patients more sensitive to romiplostim treatment with drug sensitivity proportional to time since diagnosis. In the other 50% of patients, immediate response was reduced and there was no cumulative effect of romiplostim dosing on platelet response over time. Age was associated with average platelet transit time where a patient of 30, 60, or 90 years would have a platelet transit time of 6.3, 7.5, and 8.3 days respectively. No other covariates were found to influence any model parameters.Model predicted and observed platelet responses were similar for ITP patients stratified by time from ITP diagnosis (<3, 3 to ≤ 6 and 6 to ≤ 12 months). Simulations (Figure 2) showed that romiplostim prescribed dosing is effective in maintaining PC of 50 - 250 x 10 9/L following titration (approximately 65% of subjects) and minimizing the proportion <20 or >400 x 10 9/L regardless of time since ITP diagnosis or sensitivity to romiplostim treatment. The predicted <35% of subjects above 400 x 10 9/L is consistent with what was observed in the adult ITP safety datasets.Conclusions: An updated model of romiplostim dose and platelet response was developed using data from ITP patients ≤12 months from diagnosis. Clinical trial simulations using the updated model predicted that weekly dosing of romiplostim according to the dose titration rules in the label adequately maintained platelet counts in patients with ITP ≤ 12 months from diagnosis. [Display omitted] DisclosuresGibiansky: Amgen: Consultancy. Serrano Castillo: Amgen: Current Employment, Current equity holder in publicly-traded company. Saad: Amgen: Current Employment, Current equity holder in publicly-traded company. Chow: Amgen: Current Employment, Current equity holder in publicly-traded company. Doshi: Amgen: Current equity holder in publicly-traded company; Amgen: Current Employment.

Predictors of Relapse and Survival Following Autologous Stem Cell Transplant in Patients with Diffuse Large B-Cell Lymphoma

Background: Although the majority of patients with diffuse large B-cell lymphoma (DLBCL) can be cured with intensive chemotherapy and rituximab, 30-40% of patients will be refractory to or relapse after first line treatment. For these patients, the current standard of care is salvage chemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation (ASCT). Prior studies have largely examined clinical risk factors associated with higher risk of relapse after ASCT; however, there is limited data integrating both pathologic and molecular features. Thus, we aimed to identify high-risk features associated with relapse and survival after ASCT using a combination of clinical, molecular, pathologic, and transplant characteristics.Methods: We retrospectively analyzed the medical records of all adult patients with DLBCL who underwent ASCT at our two institutions from 2010 to 2020. Patients with primary CNS lymphoma, primary mediastinal B-cell lymphoma, or Burkitt lymphoma were excluded. We analyzed demographics, clinical characteristics, cell of origin (COO) by immunohistochemistry (IHC), fluorescence in-situ hybridization (FISH) testing, and treatment/transplant characteristics. The primary endpoints were 3-year progression-free survival (PFS) and overall survival (OS) from ASCT. The Kaplan-Meier method was used to estimate survival with univariate and multivariate Cox proportional hazards regression performed to identify factors associating with PFS and OS, summarized using hazard ratios (HR) with 95% confidence intervals (CI).Results: A total of 235 DLBCL patients underwent ASCT from 2010 to 2020. Median age at ASCT was 61 years (range: 25-75) and 63% were male. At DLBCL diagnosis, 80% had advanced stage disease, 74% had extranodal involvement, 13% had poor performance status, and 65% had elevated lactate dehydrogenase (LDH). 71 patients (30%) had a prior or concurrent indolent lymphoma diagnosis indicating transformed disease. Of the patients with available COO and molecular data, 115 (60%) had germinal center B-cell (GCB) phenotype by IHC, 10 (6%) had a single MYC rearrangement by FISH, and 35 (22%) had MYC plus BCL2 and/or BCL6 rearrangements (DHL/THL). After first-line treatment, 12% remained refractory and 62% later relapsed at a median of 13 months (range: 1-240). Patients received a median of 2 (range: 1-5) lines of treatment pre-ASCT. At time of ASCT, 66% were in complete response (CR) and 32% were in partial response (PR) by standard of care imaging and response criteria.With median follow-up of 5.2 years from time of ASCT, 98 patients (42%) relapsed and 78 (33%) died. 3-year PFS and OS were 58% (95% CI 51-64%) and 74% (95% CI 67-79%), respectively. In univariate analysis, factors associated with worse PFS and worse OS included 3 or more lines of treatment pre-ASCT (p<0.01 for both) and non-CR at ASCT (p<0.01 for both) (Figure 1A and B). Transformed disease was also associated with worse PFS (p=0.03). In multivariate analysis, non-CR at ASCT remained significant (HR 2.22, 95% 1.26-3.90, p<0.01) for worse OS, along with non-GCB COO (HR 1.81, 95% CI 1.03-3.18, p=0.04) and age >60 at ASCT (HR 1.92, 95% CI 1.06-3.47, p=0.03) (Figure 1C). Stratifying by COO and disease status at transplant, 3-year OS was best in the GCB/CR group (84%, 95% CI 73-90%), while worse but similar in the GCB/non-CR and non-GCB/CR groups (68%, 95% CI 51-80% and 71%, 95% CI 56-83%, respectively) (Figure 1D). The non-GCB/non-CR group had the worst 3-year OS (48%, 95% CI 27-67%). No individual factors beyond CR/non-CR at ASCT were associated with worse 3-year PFS. Notably, DHL/THL patients (77% of whom were in CR at time of ASCT) had similar PFS (p=0.08) and OS (p=0.30) to non-DHL/THL patients, suggesting that response to therapy may be more prognostic than high-risk molecular features alone.Conclusions: This analysis indicated that factors associated with OS after ASCT were disease status at time of transplant and COO, with non-GCB patients not in CR having the poorest outcomes. GCB patients not in CR were still able to be cured by ASCT at a high rate. Molecular rearrangements including DHL/THL were not prognostic, although interpretation may be limited by the modest number of DHL/THL patients. These findings may inform which patients should undergo ASCT, while the highest risk group may be better treated with alternatives including novel targeted agents or chimeric antigen receptor cell therapy. [Display omitted] DisclosuresBachanova: FATE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; KaryoPharma: Membership on an entity's Board of Directors or advisory committees; Gamida Cell: Membership on an entity's Board of Directors or advisory committees, Research Funding. Fehniger: Compass Therapeutics: Research Funding; Affimed: Research Funding; ImmunityBio: Research Funding; Wugen: Consultancy, Current equity holder in publicly-traded company, Patents & Royalties: related to memory like NK cells, Research Funding; OrcaBio: Other; Kiadis: Other; HCW Biologics: Research Funding; Indapta: Other. Weisdorf: Fate Therapeutics: Research Funding; Incyte: Research Funding.

Late vs Early Response and Depth of Response Are Associated with Improved Outcomes in Newly Diagnosed Multiple Myeloma (NDMM) Patients (pts) Treated with Ixazomib-Lenalidomide-Dexamethasone (IRd) or Placebo-Lenalidomide-Dexamethasone (pbo-Rd) in the Phase 3 TOURMALINE-MM2 Trial

Late vs Early Response and Depth of Response Are Associated with Improved Outcomes in Newly Diagnosed Multiple Myeloma (NDMM) Patients (pts) Treated with Ixazomib-Lenalidomide-Dexamethasone (IRd) or Placebo-Lenalidomide-Dexamethasone (pbo-Rd) in the Phase 3 TOURMALINE-MM2 Trial

Sustained Improvements in Patient-Reported Quality of Life up to 24 Months Post-Treatment with LentiGlobin for Sickle Cell Disease (bb1111) Gene Therapy

Sustained Improvements in Patient-Reported Quality of Life up to 24 Months Post-Treatment with LentiGlobin for Sickle Cell Disease (bb1111) Gene Therapy

Molecular Responses Are Observed across Mutational Spectrum in Treatment-Naïve Higher-Risk Myelodysplastic Syndrome Patients Treated with Venetoclax Plus Azacitidine

Molecular Responses Are Observed across Mutational Spectrum in Treatment-Naïve Higher-Risk Myelodysplastic Syndrome Patients Treated with Venetoclax Plus Azacitidine

Coastal: A Phase 3 Study of the PI3Kδ Inhibitor Zandelisib with Rituximab (R) Versus Immunochemotherapy in Patients with Relapsed Indolent Non-Hodgkin's Lymphoma (iNHL)

Coastal: A Phase 3 Study of the PI3Kδ Inhibitor Zandelisib with Rituximab (R) Versus Immunochemotherapy in Patients with Relapsed Indolent Non-Hodgkin's Lymphoma (iNHL)

IND-Enabling Studies of a Switchable Chimeric Antigen Receptor-T Cell (CLBR001+SWI019) to Support First in Human Clinical Study

Despite the tremendous clinical benefits, adverse events associated with CAR-T cell therapy remain a challenge. Most frequent adverse events are cytokine release and immune effector cell-associated neurotoxicity syndromes due to the inability to modulate the level of activity of current CAR-T cell products after administration to patients. Additional challenges include on target, off tumor toxicities and antigen loss mediated relapse of disease.To address these challenges, we have developed a “switchable” CAR-T (sCAR-T) where the activity of the sCAR-T cells is controlled by an antibody-based switch. The switch targets the tumor antigen, and the sCAR recognizes a unique peptide engrafted on the switch. The switch creates a bridge between the sCAR-T cell and the tumor cell, activating the sCAR-T cells and inducing tumor cell killing. Combined, the switch and sCAR-T cells afford complete elimination of tumors in xenograft and syngeneic models, but individually, each is designed to be inactive. A short half-life of the switch allows for a rapid modulation of sCART-cell activity through the switch dosing. Moreover, by swapping different switches, sCAR-T cells can be modularly redirected against other tumor targets. Further, we have shown the cyclical on/off stimulation of the sCAR-T cells affords improved memory and persistence of the sCAR-T cells. Here, we report IND-enabling studies for an optimized CD19-targeted switch (SWI019) and sCAR-T cell (CLBR001) to support a first in human (FIH) clinical study of the combination.The preclinical development of a platform which includes a sCAR-T cell that lacks any endogenous antigen target, in combination with an antibody-based switch molecule that lacks intrinsic activity in the absence of the sCAR-T cell, necessitated development of novel approaches. Fidelity of such a system is essential to control, thus, to confirm CLBR001 cells did not activate in the presence of normal tissues, in vitro activity studies were performed by co-culturing CLBR001 cells, in the presence or absence of SWI019, and a panel of 14 primary cells. This panel represented a survey of vital tissues throughout the body. CLBR001 did not demonstrate activity in any of the 14 cell types tested, supporting a high fidelity of CLBR001 recognition for SWI019.Because SWI019 lacks activity in the absence of CLBR001 cells, traditional toxicology studies to identify the no adverse effect level (NOAEL) in support of the first in human starting dose were not applicable. In such cases, a minimal anticipated biological effect level (MABEL) is commonly used to support starting human dose based on the predicted Cmax; however, the femtomolar-level in vitro activity of SWI019 in combination with CLBR001 resulted in starting doses that were modeled to be far outside of the range of potential clinical activity. Therefore, an in vivo-based approach to determine MABEL was developed. CLBR001 cells were administered in NSG mice bearing CD19+ Nalm-6 cell tumors and a single dose titration of SWI019 was performed. Comparison of the SWI019 efficacious dose (ED 50) values for anti-tumor activity, peripheral cytokines, and CLBR001 cells in peripheral blood demonstrated that reduction in Nalm-6 tumor burden was the most sensitive marker of activity. Extravasation of CLBR001 cells from peripheral blood and all three cytokines (IFN-γ, IL-2, and TNF-α) exhibited weaker ED 50 values. Therefore, antitumor activity (Nalm-6 tumor burden reduction) was chosen as the parameter for which to determine in vivo MABEL. Allometric scaling, using mouse and NHP SWI019 PK data, was used to model a SWI019 recommended dose in humans corresponding to the ED 20 of the in vivo MABEL study. Compared to the dose modelled using the in vitro MABEL approach, the in vivo MABEL approach afforded a first in human starting point which was ~13000-fold higher. We expect this approach provides an excellent starting point for the first in human study which balances safety and the potential for patient benefit.In summary, the results presented in this abstract led to the initiation of clinical trial NCT04450069, the combination of CLBR001+SWI019 for the treatment of relapse/ refractory B cell malignancies. DisclosuresStone: Abbvie: Current Employment, Current equity holder in publicly-traded company. Trikha: Abbvie: Current Employment, Current equity holder in publicly-traded company. Young: Abbvie: Research Funding; Qihan Bio: Membership on an entity's Board of Directors or advisory committees; Shoreline Bio: Membership on an entity's Board of Directors or advisory committees.

GBT021601, a Next Generation HbS Polymerization Inhibitor: Results of Safety, Tolerability, Pharmacokinetics and Pharmacodynamics in Adults Living with Sickle Cell Disease and Healthy Volunteers

Background: Sickle cell disease (SCD) is caused by polymerization of sickle hemoglobin (HbS), resulting in red blood cell (RBC) sickling, RBC destruction, vaso-occlusion and end-organ damage. GBT021601 is an oral, small molecule, next-generation HbS polymerization inhibitor. Similar to voxelotor, the first generation HbS polymerization inhibitor, GBT021601 increases hemoglobin-oxygen (Hb-O2) affinity and stabilizes hemoglobin (Hb) in the oxy-hemoglobin (oxyHb) state, thereby inhibiting polymerization of HbS in RBCs. The fraction of Hb bound to drug - (Hb occupancy) approximates the oxyHb molecules per RBC. Compared to voxelotor, GBT021601 has the potential to achieve higher Hb occupancies. GBT021601 achieves greater exposures per dose and is more potent as measured by improvements in hematological parameters in an in vivo SCD mouse model (Dufu, Kobina 2020). We hypothesized that GBT021601 would achieve a substantial reduction in RBC hemolysis and increase in hemoglobin while maintaining a favorable safety profile. We therefore explored safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) in healthy volunteer participants (HVs) and adults living with SCD.Methods: Two studies are in progress: 1) the first in human (FIH), randomized, double-blind, placebo-controlled, parallel group phase 1 study for HVs ages 18-55 years; and 2) a single arm, intrapatient single dose and multiple ascending dose study in homozygous HbSS SCD patients ages 18-60 years with baseline Hb levels ≥5.5 g/dL and ≤10.5 g/dL and without vaso-occlusive crisis or transfusion within 30 days of screening. The HV study tests single ascending doses (SAD) with a 6:2 randomization ratio. Doses administered to HV cohorts ranged from 50 mg to 2200 mg. The SCD patient study tests a single dose (100 mg) followed by multiple ascending doses of the study drug in the same patients to reach a % Hb occupancy of >20-30% over 7 weeks. The primary endpoints for both studies are safety and tolerability. Secondary endpoints include PK and PD. For the patient study, additional secondary endpoints are confirmation of the relationship between time matched GBT021601 concentrations and the change from baseline of clinical measures of anemia and hemolysis. Hb occupancy is calculated as a percentage of the molar ratio of drug concentrations in RBCs to the estimated Hb concentrations (using MCHC) in RBCs.Results: As of July 22, 2021, 63 HVs and 6 adults with SCD were enrolled. Thirty-nine HVs completed the study; one discontinued due to moving to a new geographical area and 23 were in follow-up. GBT021601 was generally well-tolerated, most adverse events (AE) were Grade 1 and 2, there were no deaths, and there was one serious adverse event in a HV that was not related to the study drug. There were no AEs indicative of tissue hypoxia. GBT021601 showed linear PK, high partitioning into RBCs, and a dose dependent increase in percent hemoglobin occupancy in HVs (Figure 1). From single doses of 50 to 1400 mg, the mean preliminary % Hb occupancy ranged from 0.88 to 25%, respectively, exceeding the Hb occupancies reported for HV receiving single doses of voxelotor over a similar range (Putz, 2017).Six adults with SCD have received a single 100 mg dose of GBT021601 and the dose has been well tolerated. Multiple-dose data in adults will be presented.Conclusions: Single doses of GBT021601 are well tolerated in HV and adults with SCD. Given its drug exposure, GBT021601 has the capacity to achieve a targeted Hb occupancy and attain the desired hematological effect at low doses, therefore reducing pill burden and improving clinical outcomes for individuals living with SCD. Forthcoming multiple-dose data will help to evaluate GBT021601's potential as a best-in-class, oral, disease-modifying therapy for SCD.Funding: This study was supported by Global Blood Therapeutics. [Display omitted] DisclosuresBrown: Pfizer: Research Funding; Imara: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Forma Therapeutics: Research Funding; Novo Nordisk: Consultancy; Global Blood Therapeutics: Consultancy, Research Funding. Redfern: Eisai: Other: Advisory Board; Linear Clinical Research: Current Employment; Pfizer: Other: Advisory Board; Novartis: Other: Advisory Board; Astra Zeneca: Other: Advisory Board; Roche: Other: Advisory Board. Lisbon: Global Blood Therapeutics: Current Employment. Washington: Global Blood Therapeutics: Consultancy. Agodoa: Global Blood Therapeutics: Current Employment, Current equity holder in publicly-traded company. Smith-Whitley: Global Blood Therapeutics: Current Employment.

Neurotoxicity of Axicabtagene Ciloleucel and Long-Term Outcomes - in a Minority Rich, Ethnically Diverse Real World Cohort

IntroductionChimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of B- cell malignancies leading to durable responses in patients with relapsed/refractory disease. 1,2 One of the most severe toxicities associated with this treatment is immune effector cell-associated neurotoxicity syndrome (ICANS), which was seen in 65-75% of patients treated with axicabtagene ciloleucel (axi-cel) in initial clinical trials. ICANS can range from mild headache to coma, and can occur with or without cytokine release syndrome (CRS). Due to the recent development of CAR T-cell therapy, the long-term effects of ICANS are unknown. This study sought to determine the long-term outcomes in patients with neurotoxicity from axi-cel.MethodsWe conducted a retrospective chart review of patients who received CAR T-cell therapy with axi-cel between June 2018 and June 2021. Neurotoxicity was graded according to the American Society for Transplantation and Cellular Therapy (ASTCT) ICANS grading system. 3 The primary outcome was percentage of patients who had neurotoxicity defined as ICANS grade ≥ 1 as well as the percentage of patients with neurotoxicity lasting ≥ 1 month. We captured descriptive data such as age, sex, ethnicity, comorbidities, IPI score, stage, baseline neurologic dysfunction, performance status, and number of prior treatments. Secondary outcomes included progression free survival (PFS) and overall survival (OS).ResultsThirty-four patients received axi-cel between June 2018 and June 2021 at our institution. Median age of patients was 65. Twenty patients (59%) were male and 14 (41%) were female. The majority of patients received axi-cel for diffuse large B-cell lymphoma (97%). Study population was predominantly hispanic (35%), white (32%), African american (29%) and asian (3%). (Sixteen patients (47%) developed neurotoxicity of any grade, with 7 patients (21%) ≥ grade 3. Of note, 4 patients (12%) died during admission for CAR T-cell therapy and 3/4 deaths were in patients with ICANS ≥ grade 3. Median follow up time was 8 months. Of the 12 patients with neurotoxicity who survived initial admission for CAR-T, 9 (75%) patients recovered from neurotoxicity and mental status was at baseline at discharge without recurrence during follow up. Three (25%) of patients had prolonged neurotoxicity lasting > 1 month. Long-term neurotoxicity included confusion, disorientation,and mild cognitive impairment in the three patients. One patient recovered 15 months after CAR T-cell infusion. 2 patients had prolonged neurotoxicity resulting in deterioration of functional status and death in 1 patient, and 1 patient transitioning to hospice and being lost to follow up.ConclusionsNeurotoxicity from axicabtagene ciloleucel is a common adverse event, with half of patients in our cohort having neurotoxicity of some degree, and 20% ≥ grade 3. Twenty-five percent of patients that developed neurotoxicity had long-term effects lasting > 1 month, which resulted in deterioration of functional status in 2 patients. Long-term neurotoxicity included disorientation, confusion, and memory impairment. Our study is limited by a small sample size. Larger studies with longer follow-up times are needed to further characterize the long-term outcomes of neurotoxicity associated with CAR T-cell therapy. Neurotoxicity can be confounded by other causes of neurological dysfunction in these patients such as hospital delirium, chemotherapy toxicity, encephalopathy from infection, and subtle baseline neurologic dysfunction that may not be apparent at presentation. Next steps include prospective evaluation of patients with formal neurology evaluation prior to CAR T-cell therapy and periodically after treatment, in order to objectively monitor late neurologic effects of CAR T-cell therapy.1. Fl, L. et al. Long-term safety and activity of axicabtagene ciloleucel in refractory large B-cell lymphoma (ZUMA-1): a single-arm, multicentre, phase 1-2 trial. Lancet Oncol. 20, (2019).2. Jacobson, C. Primary Analysis of Zuma-5: A Phase 2 Study of Axicabtagene Ciloleucel (Axi-Cel) in Patients with Relapsed/Refractory (R/R) Indolent Non-Hodgkin Lymphoma (iNHL). in (ASH, 2020).3. Dw, L. et al. ASTCT Consensus Grading for Cytokine Release Syndrome and Neurologic Toxicity Associated with Immune Effector Cells. Biol. Blood Marrow Transplant. J. Am. Soc. Blood Marrow Transplant. 25, (2019). DisclosuresGritsman: iOnctura: Research Funding. Shastri: Onclive: Honoraria; Guidepoint: Consultancy; GLC: Consultancy; Kymera Therapeutics: Research Funding. Verma: Celgene: Consultancy; BMS: Research Funding; Stelexis: Current equity holder in publicly-traded company; Curis: Research Funding; Eli Lilly: Research Funding; Medpacto: Research Funding; Novartis: Consultancy; Acceleron: Consultancy; Stelexis: Consultancy, Current equity holder in publicly-traded company; Incyte: Research Funding; GSK: Research Funding; Throws Exception: Current equity holder in publicly-traded company.

Time and Side-Effect Burden Associated with Red Blood Cell Transfusions in Patients Diagnosed with Transfusion-Dependent β-Thalassemia

▪Introduction: β-thalassemia is a genetic blood disorder marked by the inability to produce hemoglobin. Diagnosed primarily in childhood, transfusion-dependent β-thalassemia (TDT) is the most severe form of this disorder and results in chronic anemia, requiring frequent red blood cell (RBC) transfusions to maintain hemoglobin levels. While previous studies have shown that health-related quality of life (HRQoL) is adversely affected in patients with TDT, the issues associated with the transfusion process itself in these patients (eg, side effects and time requirements) have not always been examined. These issues are the focus of this study.Methods: Following exploratory qualitative interviews with a small sample of patients identified by the Cooley's Anemia Foundation (CAF), a 30-minute web-based survey was developed to assess HRQoL variables in TDT. Subsequently, CAF identified patients in the US who were ≥ 18 years of age, had a self-reported physician diagnosis of β-thalassemia, and had received ≥ 1 RBC transfusion in the past 6 months, and invited them to participate in the study. Following informed consent, patients completed a number of validated and ad hoc questions about their treatment, side effects, psychological burden, time requirements for a transfusion, and caregiver information. Data were collected in May 2021. Descriptive results are presented as frequencies, means, and standard deviations (SD).Results: A total of 100 patients were identified and recruited by CAF and completed the survey. Of these, 35 (35%) were male, with a mean age of 36.0 (SD = 10.4) years. Patients had been diagnosed with TDT for a mean of 34.4 years (SD = 10.3) and had received a mean of 9.6 (SD = 4.3) RBC transfusions in the previous 6 months. In addition to receiving RBC transfusions (100%), other treatments ever received for TDT included iron chelation therapy (94%), surgery (47%), and stem cell/bone marrow transplantation (5%). Regarding RBC transfusions, 66% of patients reported requiring them more than once per month, 31% each month, and 3% every other month. Common patient-reported side effects of RBC transfusions were iron overload (81%), rashes/hives (74%), fatigue (61%), and pain/bruising at the injection site (52%). Additionally, 86% of patients reported feeling fatigued leading up to RBC transfusions, 75% reported that treatments for TDT had become routine, and 64% accepted the routine. Time required for an RBC transfusion was estimated at a mean of 7.4 hours (SD = 11.3) including transfusion preparation time. Travel and wait times were estimated as requiring an additional 7.1 hours. Other time requirements included frequent outpatient visits and frequent laboratory tests, averaging 3.9 visits and 6.1 visits in a 6-month period, respectively. Overall, 13% of patients reported having a caregiver. Caregiver activities included travel to and from appointments (77%), help with household duties (77%), and assistance in treatment decisions (62%).Conclusions: The results of this survey suggest there is a substantial time and side-effect burden associated with transfusion and treatment among patients diagnosed with TDT. This includes considerable time devoted to preparing for and receiving transfusions, transfusion-related side effects, frequent laboratory and outpatient appointments, and help from a caregiver. Medical treatments that would decrease the dependency on transfusions in TDT could decrease this burden and improve overall quality of life. DisclosuresGupta: Kantar Health: Current Employment; Bristol Myers Squibb: Consultancy, Research Funding. Costantino: Kantar Health: Current Employment; Bristol Myers Squibb: Consultancy, Research Funding. Perkowski: Kantar Health: Current Employment; Bristol Myers Squibb: Consultancy, Research Funding. Inyart: Kantar Health: Current Employment; Bristol Myers Squibb: Consultancy, Research Funding. Ashka: Kantar Health: Current Employment; Bristol Myers Squibb: Consultancy, Research Funding. Clapp: Kantar Health: Current Employment; Bristol Myers Squibb: Consultancy, Research Funding. Price: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Knoth: Bristol Myers Squibb: Current Employment.

Changes in Hemoglobin Measures Observed in PNH Patients Treated with Both C5 Inhibitors Ravulizumab and Eculizumab: Real-World Evidence from a US-Based EMR Network

Changes in Hemoglobin Measures Observed in PNH Patients Treated with Both C5 Inhibitors Ravulizumab and Eculizumab: Real-World Evidence from a US-Based EMR Network

Predictors of Central Nervous System (CNS) Involvement in North American Adult T-Cell Leukemia Lymphoma (ATLL) and Their Survival Pattern

▪Introduction:North American-ATLL (NA-ATLL) is a distinct genomic and clinical entity when compared with Japanese ATLL. Despite the frequent CNS involvement by this entity there are no prognostication tools to identify variables associated with higher risk. We studied one of the largest NA-ATLL cohorts in the United States at a minority rich ethnically diverse New York City based tertiary care center to identify discrete variables that may be associated with CNS involvement. Additionally, we examined the predictive power of the previously validated International Prognostic Index (IPI) developed for Diffuse Large B-cell Lymphoma (DLBCL) in terms of CNS involvement as well as overall survival in our cohort.In our previous work, we assigned CNS involvement of ATLL if: 1) cerebrospinal fluid (CSF) cytology or flow cytometry was positive; 2) CNS imaging was positive for disease involvement or 3) physical exam was compatible with neurologic involvement.Methods and results:Of 65 NA-ATLL patients (pts), 20 (30.77%) had CNS involvement by ATLL meeting above mentioned criteria. The median age of all pts in our dataset was 59 years. Pts were divided into non- CNS involved NA-ATLL (non-CNS NA-ATLL) and CNS involved NA-ATLL (CNS NA-ATLL) groups. Parameters to predict CNS involvement were outlined as leukocytosis (>11000 per microliter [μL]), elevated acute lymphocytic count (>4000/ μL), elevated lactate dehydrogenase (LDH) (>190 units/liter [u/l]), generalized lymphadenopathy (LAD) defined as involvement of 2 or more non-contiguous nodal sites, elevated corrected serum calcium levels (>10.5 mg/deciliter), bone marrow (bm) involvement and serosal involvement defined as pleural or peritoneal involvement. These variables were chosen given our prior work identifying them as critical to predict OS in our general NA-ATLL population.We then performed the Fisher test of proportions to determine if the variables above mentioned were different between the CNS NA-ATLL and the non-CNS NA-ATLL. We did not find significant associations when analyzing gender (p=0.0535), leukocytosis (p= 0.4001), lymphocytosis (p =0.57), hypercalcemia (p= 0.7661), elevated LDH (p= 0.4898), generalized LAD (p=0.271), serosal involvement (p= 0.05088) or bone marrow involvement (p=1). We only found a strong association when examining ATLL subtypes, being the acute/lymphomatous variant strongly associated with CNS involvement (p=2.226e10 -5).To identify variables that can have an impact in OS in CNS NA-ATLL vs non-CNS NA-ATLL we calculated Kaplan Meier survival curves. We did not find any difference based on age (p=0.23), gender (p=0.95), leukocytosis (p= 0.074), lymphocytosis (p =0.21), hypercalcemia (p= 0.094), elevated LDH (p= 0.37), generalized LAD (p=0.28), and serosal involvement (p= 0.1) in the overall survival. The only significant association we found was bone marrow involvement in predicting poor OS in CNS NA-ATLL group (p= 0.038).Next, we determined IPI scores (age>60, ECOG performance status>2, Ann Arbor stage III/IV, serum LDH score >190 u/L and more than 1 extra-nodal site) in our CNS NA ATLL and non-CNS NA ATLL cohorts. We sought to determine if: 1) this prognostication tool is predictive in NA-ATLL and 2) if these variables can be used to identify CNS involvement in our cohort.CNS pts with a higher IPI score (>3) showed tendency towards a lower survival rate (p=0.089) than non-CNS pts (p=0.3). IPI score of 3 or more was not predictive of CNS involvement in our sample (p=1).Conclusions:NA-ATLL is a rare and protean disease with poor prognosis and CNS involvement is prevalent. With the variables used we did not find clear predictors of CNS associated disease other than patients presented with the lymphomatous and acute subtypes. We also observed than bone marrow involvement portends a dismal prognosis for individuals with CNS involvement. Future studies with a larger cohort could provider further insight on discovering predictors for CNS involvement in NA ATLL. [Display omitted] DisclosuresShah: Celgene/BMS: Research Funding; Janssen: Research Funding. Gritsman: iOnctura: Research Funding. Shastri: GLC: Consultancy; Kymera Therapeutics: Research Funding; Guidepoint: Consultancy; Onclive: Honoraria. Verma: BMS: Research Funding; GSK: Research Funding; Incyte: Research Funding; Medpacto: Research Funding; Curis: Research Funding; Eli Lilly: Research Funding; Stelexis: Consultancy, Current equity holder in publicly-traded company; Novartis: Consultancy; Acceleron: Consultancy; Celgene: Consultancy; Stelexis: Current equity holder in publicly-traded company; Throws Exception: Current equity holder in publicly-traded company. Janakiram: Amgen: Honoraria.

Preclinical Results of an Allogeneic, Universal CD19/CD7-Targeting CAR-T Cell Therapy (GC502) for B Cell Malignancies

BackgroundAutologous CD19 CAR-T therapies show very promising clinical efficacy, but are limited in their applicability by several factors including cost, time to manufacture, and other factors involving patients own T-cell qualities. GC027, a CD7 targeting allogeneic, universal CAR-T (UCAR-T) currently in development for the treatment of T-cell acute lymphoblastic leukemia (T-ALL) has demonstrated robust expansion and anti-leukemia efficacy with a manageable safety profile in an investigator-initiated trial in China. These data suggest that, a single CD7 targeting CAR-T therapy is able to generate a therapeutic window by suppressing host vs graft (HvG) rejection of UCAR-T cells by patients' own NK and T cells, and achieve efficacy in patients with T-ALL. Based on these findings we developed GC502, a CD19/CD7 dual-targeting, allogeneic CAR-T therapy for B-cell malignancies, in which the CD19 CAR moiety targets malignant cells while CD7 CAR moiety suppresses HvG in variety of preclinical models.MethodsGC502 was manufactured using leukopaks from HLA-unmatched healthy donors. It contains a 4-1BB based 2 nd-generation dual targeting CAR comprising an anti-CD19 and an anti-CD7 single-chain variable fragments (scFvs). TRAC and CD7 loci were disrupted to avoid graft vs host disease and fratricide, respectively. To select the leading CAR candidate, CAR expression and functionalities of CAR constructs with different heavy-light (H-L) chain orientations of the dual CAR were analyzed via in vitro assays and mouse xenograft models, in comparing to single CD19 CAR and CD7 CAR products. To achieve optimal anti-tumor efficacy, a T-cell enhancer was included in the CAR construct.ResultGene editing and dual CAR orientation selectionTRAC and CD7 double knockout efficiencies were constantly above 97% across multiple donor pan T cells. Although CD19/CD7 CAR expression levels in different H-L chain orientations were similar, in the final CAR-T product as measured by flow cytometry (FCM) analysis, significant difference was observed in their cytotoxicity and in vitro expansion under repeated antigen stimulations by CD19+ B-cell acute lymphoblastic leukemia (B-ALL) cell line Nalm6 and CD7+ T-cell line CCRF-CEM. CAR candidates mediated the strongest cytotoxicity and most durable response were selected for further optimizations.CAR construct optimizationsFor the leading candidates, we first assessed the dual CAR efficacy after incorporation of an enhancer. While the IL-2, TNFα and IFNγ secretion levels were comparable, enhancer addition significantly improved tumor killing and CAR-T cell expansion under repeated stimulations by either CD19+ or CD7+ target cells. Anti-leukemia response under sub-optimal CAR-T cell dosages were also greatly enhanced as assessed by both B-ALL and T-ALL mouse xenograft models.GC502 CAR functionality comparison to single CAR products with proven clinical efficaciesGC502 and GC027 were compared for their CD7 CAR function to assess their anti-HvG activities. GC502 and GC027 exhibited comparable toxicities towards pan T cells and similar efficacies in a highly malignant T-ALL mouse model. The CD19 CAR functionality of GC502 were evaluated and compared to a 2 nd generation CD19 CAR product comprising a FMC63 scFv and a 4-1BB-CD3ȥ signaling domain. In a Raji based B-ALL mouse xenograft model, both products rapidly eliminated cancer cells. While CD19 CAR treated mice showed signs of relapse at 2 weeks post CAR-T infusion, GC502 treatment group maintained “leukemia free” status till the end of study (Day28).ConclusionGC502 was optimized for CD19/CD7 dual CAR functionality and in vivo durability. It demonstrated robust anti-tumor efficacy and promising potentials to suppress HvG. This report presents an example that the dual CAR design of GC502 may serve as a novel “off-the-shelf” CAR-T technology. DisclosuresGe: GracellBiotechnologies Ltd: Current Employment, Current equity holder in publicly-traded company. Yang: GracellBiotechnologies Inc: Current Employment, Current equity holder in publicly-traded company. Sun: GracellBiotechnologies Inc: Current Employment, Current equity holder in publicly-traded company. Chen: GracellBiotechnologies Inc: Current Employment, Current equity holder in publicly-traded company. Qiu: GracellBiotechnologies Inc: Current Employment, Current equity holder in publicly-traded company. Yin: GracellBiotechnologies Inc: Current Employment, Current equity holder in publicly-traded company. Shen: GracellBiotechnologies Inc: Current Employment, Current equity holder in publicly-traded company. Sersch: GracellBiotechnologies Inc: Current Employment, Current equity holder in publicly-traded company. Cao: GracellBiotechnologies Inc: Current Employment, Current equity holder in publicly-traded company. Wang: GracellBiotechnologies Inc: Current Employment, Current equity holder in publicly-traded company.