Equity Holder Research Articles

Rejuvenated BCMA-Specific CD8 + Cytotoxic T Lymphocytes Derived from Antigen-Specific Induced Pluripotent Stem Cells : Immunotherapeutic Application in Multiple Myeloma

T cell regenerative medicine represents an emerging immunotherapeutic approach using antigen-specific Induced Pluripotent Stem Cells (iPSC) to rejuvenate CD8 + cytotoxic T lymphocytes (CTL). Here we report on an iPSC-derived therapeutic strategy targeting B-Cell Maturation Antigen (BCMA) against multiple myeloma (MM) via establishment of antigen-specific iPSC, followed by differentiation into highly functional BCMA-specific CD8 + CTL. The reprogrammed BCMA-specific iPSC displayed normal karyotypes and pluripotency potential as evidenced by expression of stem cell markers (SSEA-4, TRA1-60) and alkaline phosphatase, along with differentiation into three germ layers (Ectoderm, Mesoderm, Endoderm). During embryoid body formation, BCMA-specific iPSC further polarized into the mesoderm germ layer, evidenced by the activation of SNAI2, TBX3, PLVAP, HAND1 and CDX2 transcriptional regulators. Next, the BCMA-specific iPSC clones committed to CD8 + T cell differentiation were characterized by analyzing their hematopoietic progenitor cells (HPC; CD34 + CD43 +/CD14 - CD235a -) for specific transcriptional regulation. RNAseq analyses indicated a low variability and similar profiles of gene transcription within the iPSC clones committed to CD8 + CTL compared to increased transcriptional variability within iPSC clones committed to different cell types. The unique transcriptional profiles of the iPSC committed to CD8 + T cells included upregulation of transcriptional regulators controlling CD4/CD8 T cell differentiation ratio, memory CTL formation, NF-kappa-B/JNK pathway activation, and cytokine transporter/cytotoxic mediator development, as well as downregulation of regulators controlling B and T cell interactions, CD4 + Th cells, and inhibitory receptor development. Specifically, a major regulatory shift, indicated by upregulation of specific genes involved in immune function, was detected in HPC from the iPSC committed to CD8 + T cells. BCMA-specific T cells differentiated from the iPSC were characterized as displaying mature CTL phenotypes including high expression of CD3, CD8a, CD8b, TCRab, CD7 along with no CD4 expression (Fig. 1). In addition, the final BCMA iPSC-T cells were predominantly CD45RO + memory cells (central memory and effector memory cells) expressing high level of T cell activation (CD38, CD69) and costimulatory (CD28) molecules. Importantly, these BCMA iPSC-T cells lacked immune checkpoints (CTLA4, PD1, LAG3, Tim3) expression and regulatory T cells induction, distinct from other antigen-stimulated T cells. The rejuvenated BCMA iPSC-T cells demonstrated a high proliferative (1,000 folds increase) during the differentiation process as well as poly-functional anti-tumor activities and Th1 cytokine (IFN-g, IL-2, TNF-a) production triggered in response to MM patients' cells in HLA-A2-restricted manner (Fig. 2). Furthermore, the immune responses induced by these BCMA iPSC-T cells were specific to the parent heteroclitic BCMA 72-80 (YLMFLLRKI) peptide used to reprogram and establish the antigen-specific iPSC. Evaluation of 88 single cell Tetramer + CTL from the BCMA iPSC-T cells revealed a clonotype of unique T cell receptor (TCRa, TCRb) sequence. The BCMA-specific iPSC clones maintained their specific differentiation potential into the antigen-specific CD8 + memory T cells, following multiple subcloning in long-term cultures under feeder-free conditions or post-thaw after long-term (18 months) cryopreservation at -140 oC, which provides additional benefits to treat patients in a continuous manner. Taken together, rejuvenated CD8 + CTL differentiated from BCMA-specific iPSC were highly functional with significant (*p < 0.05) levels of anti-MM activities including proliferation, cytotoxic activity and Th-1 cytokine production. Therefore, the antigen-specific iPSC reprogramming and T cells rejuvenation process can provide an effective and long-term source of antigen-specific memory CTL lacking immune checkpoints and suppressors for clinical application in adoptive immunotherapy to improve patient outcome in MM. [Display omitted] DisclosuresMunshi: Amgen: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy; Adaptive Biotechnology: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy; Abbvie: Consultancy; Janssen: Consultancy; Legend: Consultancy; Oncopep: Consultancy, Current equity holder in publicly-traded company, Other: scientific founder, Patents & Royalties; Novartis: Consultancy; Pfizer: Consultancy. Ritz: Amgen: Research Funding; Equillium: Research Funding; Kite/Gilead: Research Funding; Avrobio: Membership on an entity's Board of Directors or advisory committees; Akron: Consultancy; Biotech: Consultancy; Blackstone Life Sciences Advisor: Consultancy; Clade Therapeutics, Garuda Therapeutics: Consultancy; Immunitas Therapeutic: Consultancy; LifeVault Bio: Consultancy; Novartis: Consultancy; Rheos Medicines: Consultancy; Talaris Therapeutics: Consultancy; TScan Therapeutics: Consultancy. Anderson: Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Millenium-Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Scientific Founder of Oncopep and C4 Therapeutics: Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Mana Therapeutics: Membership on an entity's Board of Directors or advisory committees.

A Novel Methodology for Building Longitudinal, Patient-Centric Real World Datasets in Hemophilia A

A Novel Methodology for Building Longitudinal, Patient-Centric Real World Datasets in Hemophilia A

CC-92480 Enhances Cell-Autonomous Cytotoxicity through Blockade of G 2/M Transition When Combined with Bortezomib/Dexamethasone in Pre-Clinical Multiple Myeloma

Background: Pomalidomide (POM) is an established agent in relapsed/refractory (R/R) multiple myeloma (MM). CC-92480, a novel cereblon E3 ligase modulator (CELMoD ®) agent, is being investigated in R/R MM patients in combination with the proteasome inhibitor (PI) bortezomib (BTZ) and steroid dexamethasone (DEX) (NCT03374085/NCT03989414). Previously, we showed mechanistic synergy of POM/BTZ/DEX in MM cell line models (Bjorklund et al). Here we analyzed the cell autonomous cytotoxic activities of CC-92480 or POM alone and in combination with BTZ/DEX to compare and differentiate their mechanisms of action (MOA).Results:Comparative analysis of the anti-proliferative activity against H929 and MM1.S cell lines revealed that CC-92480 demonstrated a more potent inhibition of proliferation by 100-fold lower dose compared to POM. Combination experiments utilizing a titration of POM or CC-92480 in combination with a 1 hr BTZ pulse, to mimic the clinical pharmacokinetics (+/- DEX co-treatment) showed an enhancement of antiproliferative capacity in both doublet and triplet combinations compared to single agents. Combination indices for POM/BTZ/DEX or CC-92480/BTZ/DEX resulted in values <1 for most combinations indicating a synergistic effect. Additionally, POM or CC-92480 in combination with BTZ or DEX, or in triplet combinations increased induction of apoptosis (>90% for each triplet compared to POM (20%) and CC-92480 (40%). Flow cytometric analysis of Aiolos and Ikaros protein level in MM cells treated with POM/BTZ/DEX or CC-92480/BTZ/DEX resulted in a slight kinetic delay in substrate depletion at early time points (1-4 hr), where the effect is less apparent with CC-92480, and indistinguishable at 24 hr compared to single agent POM or CC-92480 in the clinically relevant concentrations.We performed transcriptomic analyses of H929 cells treated with POM/BTZ/DEX or CC-92480/BTZ/DEX for 24 hrs to identify key pathways responsible for the observed synergistic combination effect. Common pathways dysregulated by POM or CC-92480 included previously identified interferon, protein homeostasis and proliferation gene sets. Gene set enrichment analysis (GSEA) showed many significant pathway differences when comparing the triplets, including general cell cycle progression, cell division and chromatin segregation. Interestingly, genes involved in negative regulation of G 2/M transition were identified as one of the most significant differences between POM/BTZ/DEX and CC-92480/BTZ/DEX.To understand how these pathways contributed to cell cycle effects and apoptosis, we assessed DNA fragmentation by TUNEL in conjunction with cell cycle flow cytometry to examine cell cycle specific apoptotic induction. Temporal assessment (6, 12, 18, 24, and 48 hr treatments) demonstrated accumulation of BrdU incorporation in all cell cycle phases when treated with POM/BTZ/DEX or CC-92480/BTZ/DEX indicating cell death was occurring within all phases. However, there was a marked enhancement of G 2/M BrdU incorporation (80% vs. 40% of G 2/M population) at 18-24 hr when treated with CC-92480/BTZ/DEX compared to POM/BTZ/DEX, or other single agent treatments. Additionally, G 2/M transition-dependent cyclins A and B were shown to be dysregulated by CC-92480. These data indicate that CC-92480 potentiates a G 2/M arrest in combination with BTZ in MM cells.Conclusions: These results demonstrate that CC-92480 alone or in combination with BTZ/DEX elicits a more potent cytotoxic effect on MM cells compared to POM. Importantly, the combination of either POM or CC-92480 with a PI, like BTZ, does not appreciatively affect single agent MOA. We have also identified a key differentiating mechanism of cell autonomous activity for CC-92480 in combination with BTZ/DEX where MM cells enhance apoptotic induction at the G 2/M stage compared to POM. Clinically, this added mechanistic difference suggests a more cytotoxic response in patients treated with CC-92480/BTZ/DEX compared to POM/BTZ/DEX. DisclosuresBjorklund: BMS: Current Employment, Current equity holder in publicly-traded company. Amatangelo: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Kang: BMS: Current equity holder in publicly-traded company. Chiu: Bristol Myers Squibb: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Pourdehnad: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: No royalty. Hagner: BMS: Current Employment, Current equity holder in publicly-traded company. Thakurta: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company.

Brentuximab Vedotin, Nivolumab, Doxorubicin, and Dacarbazine (AN+AD) for Advanced Stage Classic Hodgkin Lymphoma: Preliminary Safety Results from the Single-Arm Phase 2 Study (SGN35-027 Part B)

Brentuximab Vedotin, Nivolumab, Doxorubicin, and Dacarbazine (AN+AD) for Advanced Stage Classic Hodgkin Lymphoma: Preliminary Safety Results from the Single-Arm Phase 2 Study (SGN35-027 Part B)

Lower-Risk Myelodysplastic Syndromes: Erythropoiesis-Stimulating Agent Treatment Approaches and Outcomes in the United States

Lower-Risk Myelodysplastic Syndromes: Erythropoiesis-Stimulating Agent Treatment Approaches and Outcomes in the United States

A Phase 2, Open-Label, Multiarm, Multicenter Study to Evaluate Magrolimab Combined with Antileukemia Therapies for First-Line, Relapsed/Refractory, or Maintenance Treatment of Acute Myeloid Leukemia

A Phase 2, Open-Label, Multiarm, Multicenter Study to Evaluate Magrolimab Combined with Antileukemia Therapies for First-Line, Relapsed/Refractory, or Maintenance Treatment of Acute Myeloid Leukemia

Development of a Cold Agglutinin Disease-Specific Patient-Reported Outcome Symptom Measure

IntroductionCold agglutinin disease (CAD) is a rare autoimmune hemolytic anemia in which red blood cells are bound by cold agglutinin autoantibodies. In addition to cold-induced symptoms, patients with CAD experience symptoms of chronic anemia and hemolysis including fatigue, weakness, and shortness of breath (Swiecicki PL et al. Blood 2013;122(7):1114-21). The objectives of this study were to identify disease-related symptoms and impacts most important to patients with CAD, and to evaluate whether existing patient-reported outcome (PRO) measures are appropriate to assess relevant CAD concepts.MethodsAs part of a larger study, qualitative concept elicitation (CE) interviews were conducted to better understand the disease burden of CAD from the patient perspective. The results from the first set of interviews were reported by Su J et al. Blood 2020;136(1):29-30. Based on the identified symptoms and impacts, standard survey methodological principles were used to develop a draft item pool to address concepts of interest. Items were refined and evaluated during the second set of interviews, which included 3 rounds of 60-minute phone interviews with patients with CAD using a semi-structured interview guide that included a CE section and cognitive debriefing. Pooled results from both sets of interviews were used to develop a conceptual model of the symptoms and impacts of CAD. Physician advisors were also invited to review the concepts identified in the interviews and to select those that they believed were most relevant as part of an advisory board.A PubMed review of literature published between 2010-2020 was also conducted to identify existing PRO measures used in the assessment of symptoms, impacts, and/or quality of life and patient experiences in adults with CAD or similar disease areas. Identified PRO measures were assessed to determine the extent to which they captured CAD-specific concepts identified in the CE interviews.ResultsIn total, 37 participants diagnosed with primary or secondary CAD took part in the interviews (Set 1, n=16; Set 2, n=21). Overall, the mean age of participants was 67.2 years (range: 35-87), and the majority were female (73%).The most frequently reported symptom of CAD was reactions to cold environments (n=36; 97%), e.g., cold or numb feet/hands, and skin discoloration. Other reported symptoms included fatigue (n=35; 95%), shortness of breath (n=28; 76%), and trouble with thinking/concentration (n=21; 57%). The most frequently reported unfavorable impact of CAD was on day-to-day activities (n=32; 87%). Other negative impacts included effects on enjoyable activities (n=29; 78%) e.g., gardening, physical health/activities (n=28; 76%), social/leisure life (n=26; 70%); and mood/emotions (n=24; 65%). Most participants (n=30; 81%) reported they had made lifestyle/behavioral changes to help limit their CAD symptoms, such as wearing extra clothing in places that were likely to be cold. A conceptual model of the symptoms and impacts of CAD was developed based on these data (Figure 1). Physician advisors (n=7) agreed that the patient-reported symptoms and impacts identified during the interviews were relevant concepts to CAD.Following a literature review, no existing PRO measure was found to adequately address concepts deemed critical to CAD from the patient perspective. Owing to the lack of an existing fit-for-purpose measure, 14 concepts were identified from the interviews to develop an initial draft item pool. During the cognitive debriefing in the second set of interviews, participants (n=21: Round 1 n=8; Round 2 n=7; Round 3 n=6) evaluated these concepts. After 3 rounds of interviews, the new item set yielded 11 items relating to: fatigue; cold sensitivity; dyspnea; wearing extra clothing; limited physical, social, and enjoyable activities; difficulty with usual activities; mood; frustration; and anxiety/stress. Participants reported these items were comprehensive of their experiences with CAD, easy to understand, and would be relevant to gaining a better understanding of individuals' experiences with CAD.ConclusionThese results support the need for a novel PRO measure(s) that adequately addresses concepts critical to the measurement of CAD symptoms and impacts from the patient perspective. [Display omitted] DisclosuresJoly: Sanofi: Current Employment. Dasmahapatra: Sanofi: Current Employment, Current equity holder in publicly-traded company. Su: Sanofi: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Astellas US LLC: Current Employment. DiBenedetti: RTI Health Solutions: Current Employment, Other: Employee of RTI Health Solutions, funded by Sanofi Genzyme to conduct the original work which this abstract is based on. Kosa: RTI Health Solutions: Current Employment. Hill: Novartis: Consultancy, Honoraria; Grifols: Consultancy, Honoraria; Sanofi: Consultancy; ReAlta: Consultancy; Alexion: Honoraria; Amgen: Honoraria; Argenx: Consultancy; Apellis: Consultancy, Honoraria.

Long-Term Results of Alliance A041202 Show Continued Advantage of Ibrutinib-Based Regimens Compared with Bendamustine Plus Rituximab (BR) Chemoimmunotherapy

Long-Term Results of Alliance A041202 Show Continued Advantage of Ibrutinib-Based Regimens Compared with Bendamustine Plus Rituximab (BR) Chemoimmunotherapy

Ciltacabtagene Autoleucel for Triple-Class Exposed Multiple Myeloma: Adjusted Comparisons of CARTITUDE-1 Patient Outcomes Versus Therapies from Real-World Clinical Practice from the LocoMMotion Prospective Study

Ciltacabtagene Autoleucel for Triple-Class Exposed Multiple Myeloma: Adjusted Comparisons of CARTITUDE-1 Patient Outcomes Versus Therapies from Real-World Clinical Practice from the LocoMMotion Prospective Study

Rusfertide (PTG-300), a Hepcidin Mimetic, Maintains Liver Iron Concentration in the Absence of Phlebotomies in Patients with Hereditary Hemochromatosis

▪Introduction: Patients with hereditary hemochromatosis (HH) require continued phlebotomies to limit end-organ damage. Approximately 25% of patients in maintenance felt receiving phlebotomies was “inconvenient” or “very inconvenient” (Brisott et al, 2011). Patient compliance with phlebotomies generally declines with time (Hicken et al, 2003), and therapeutic phlebotomies may not be medically suitable for some HH patients. Rusfertide, a peptide mimetic of hepcidin, is an effective regulator of iron distribution and utilization that has demonstrated control of iron in an animal model of HH.Methods: We conducted an open-label, dose-finding efficacy study that investigated subcutaneous rusfertide in HH patients on a stable phlebotomy regimen of 0.25 to 1 phlebotomy per month for at least 6 months. Patients with clinical laboratory abnormalities and those receiving iron chelation therapy or erythrocytapheresis were excluded. Subjects received individually titrated rusfertide doses once or twice a week to maintain transferrin saturation (TSAT) below 45% and were followed for 6 months. Study measures included TSAT, serum iron, transferrin and ferritin, liver iron concentration (LIC) measured by MRI, and adverse events (AEs).Results: Sixteen subjects (10 male/6 female) were enrolled. Mean age and weight were 62.5 years and 88.1 kg, respectively. LIC values were maintained at pre-study levels, with minimal use of phlebotomies during the duration of the study (Figure 1A). Average pre-study phlebotomy rate was 0.27 phlebotomies/month compared to 0.03 phlebotomies/month during the study (p<0.0001; Figure 1B). There was a dose- and concentration-dependent decrease in serum iron and TSAT (Figure 2A and 2B). Transferrin levels were relatively constant over the course of the study. There were no notable changes in hematological parameters such as hematocrit, erythrocytes, leucocytes, or platelets. Rusfertide was generally well tolerated. Adverse events reported in 2 or more subjects included diarrhea, fatigue, injection site reactions (erythema, induration, pain, pruritis), dizziness, and headache.Conclusions: Rusfertide demonstrated a pharmacodynamic effect in reducing TSAT and serum iron, with corresponding significant reduction in the number of phlebotomies, and with LIC maintained at pre-study levels with minimal use of phlebotomies. These data indicate rusfertide was well tolerated in patients with HH and controls LIC, supporting development of rusfertide as a potential treatment for HH. [Display omitted] DisclosuresKowdley: PTG: Consultancy, Research Funding. Modi: Protagonist Therapeutics: Current Employment. Valone: Protagonist Therapeutics: Current Employment, Current equity holder in publicly-traded company. Gupta: Protagonist Therapeutics: Current Employment.

Posoleucel (ALVR105), an Off-the-Shelf, Multivirus-Specific T-Cell Therapy, for the Prevention of Viral Infections Post-HCT: Results from an Open-Label Cohort of a Phase 2 Trial

Posoleucel (ALVR105), an Off-the-Shelf, Multivirus-Specific T-Cell Therapy, for the Prevention of Viral Infections Post-HCT: Results from an Open-Label Cohort of a Phase 2 Trial

In Multiple Myeloma, High-Risk Secondary Genetic Events Observed at Relapse Are Present from the Diagnosis in Tiny Undetectable Subclones

In Multiple Myeloma, High-Risk Secondary Genetic Events Observed at Relapse Are Present from the Diagnosis in Tiny Undetectable Subclones

Updated Results from MajesTEC-1: Phase 1/2 Study of Teclistamab, a B-Cell Maturation Antigen x CD3 Bispecific Antibody, in Relapsed/Refractory Multiple Myeloma

Updated Results from MajesTEC-1: Phase 1/2 Study of Teclistamab, a B-Cell Maturation Antigen x CD3 Bispecific Antibody, in Relapsed/Refractory Multiple Myeloma

Chromatin Remodeling and Associated Changes in Gene Expression Induced By Bone Marrow Stromal Cells Identify Features of High-Risk Multiple Myeloma

Introduction: Stromal cells in the bone marrow microenvironment maintain a complex bidirectional relationship with the malignant plasma cells and have been implicated in the growth and survival of multiple myeloma (MM) cells along with the development of drug resistance and disease progression. We hypothesized that the perpetual induction of gene expression changes similar to those induced by stromal interactions may lead to an aggressive disease phenotype and possible stromal independence. We investigated the chromatin remodeling and associated gene expression changes in malignant plasma cells induced by stromal cells and applied the findings to large sets of patient data.Methods: We interrogated the chromatin accessibility (ATAC-seq) and gene expression profiles (RNA-seq) of malignant plasma cells (INA6, MM1S, RPMI) after co-culture with stromal cells (HS5). We identified de novo accessible enhancers and associated them with their putative target genes within conserved topologically associating domains based on their proximity in the linear genome. The in vitro data were then applied to data from patients with newly diagnosed MM (n=559). Using proportional hazards regression and automated feature selection algorithms we selected 10 of the 68 overexpressed target genes based on their association with progression-free survival. We devised a dichotomous classifier based on the expression of these 10 genes and validated its independent prognostic significance and ability to predict therapeutic resistance in two additional patient cohorts (n=214 and n=635, respectively). We applied gene set enrichment analysis to interrogate whether the gene expression profile induced by these adverse stromal interactions recapitulates the transcriptional program of extramedullary malignant plasma cells using single-cell RNA-seq.Results: Co-culture of malignant plasma cells with stromal cells induced widespread chromatin remodeling including de novo accessibility of known cis-regulatory elements and the overexpression of their putative target genes (68 overexpressed genes with associated accessible enhancers, overlap p=1.05x10 -13). The expression of 10 of these 68 genes was independently associated with progression-free survival in the UAMS TT2/3 data set (n=559). A summary measure of the expression of these 10 genes was dichotomized to classify approximately 30% of patients as having adverse stromal interactions (ASI+). The 10-gene ASI+ classifier was associated with overall survival in three independent patient cohorts with newly diagnosed MM: UAMS TT2/3 (29% ASI+, HR 1.93, 95% CI 1.43-2.62, p<0.001, n=559), IFM 2009 (32% ASI+, HR 2.61, 95% CI 1.67-4.10, p<0.001, n=214), and MMRF IA16 (30% ASI+, HR 1.69, 95% CI 1.29-2.24, p<0.001, n=635). Its prognostic significance was independent of age, sex, ISS stage, elevated LDH, high-risk cytogenetics, and the high-risk transcriptomic classifiers (UAMS-70, EMC-92). The 10-gene ASI+ classifier predicted resistance to first-line therapy in general and to treatment with VRd in particular (OR 1.64, 95% CI 1.10-2.43, p=0.015, MMRF IA16, n=211). Gene set enrichment analysis demonstrated that the gene expression profile of patients with ASI+ recapitulates the transcriptional program of extramedullary malignant plasma cells (5376 circulating plasma cells, NES 1.41, FDR=0.027; 477 plasma cells from malignant effusions, NES 1.37, FDR=0.029). This extramedullary-like gene expression pattern translated into a higher prevalence of circulating plasma cells among newly diagnosed ASI+ patients (54% versus 35%, p=1.65x10 -5, MMRF IA16, n=629) and a higher incidence of bone disease and plasmacytoma progression during follow-up (HR 2.24, 95% CI 1.51-3.31, p<0.001, MMRF IA16, n=622).Conclusions: We identified permissive chromatin states and associated transcriptional programs induced by the interactions between MM cells and bone marrow stromal cells. The constitutive induction of genes in the malignant plasma cells of patients with newly diagnosed MM supported transcriptional programs associated with therapeutic resistance, accelerated disease dissemination, and impaired long-term survival. These changes may allow MM cells to acquire the capacity to sustain extramedullary growth. The development of novel therapeutic approaches to overcome these adverse stromal interactions remains an unmet need in patients with MM. DisclosuresMunshi: Adaptive Biotechnology: Consultancy; Karyopharm: Consultancy; Abbvie: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Amgen: Consultancy; Oncopep: Consultancy, Current equity holder in publicly-traded company, Other: scientific founder, Patents & Royalties; Novartis: Consultancy; Legend: Consultancy; Pfizer: Consultancy.

Gut Microbiota Tuning Promotes Tumor-Associated Antigen Cross Presentation and Enhances CAR T Antitumor Effects

Gut Microbiota Tuning Promotes Tumor-Associated Antigen Cross Presentation and Enhances CAR T Antitumor Effects

Combination Therapy of Bcl-2/X L dual Inhibitor AZD0466 with Acalabrutinib to Overcome Therapeutic Resistance in Aggressive R/R Mantle Cell Lymphoma

IntroductionAs a rare form of non-Hodgkin's lymphoma, mantle cell lymphoma (MCL) is an aggressive subtype. This is largely due to frequent relapses after therapies including paradigm shifting therapies BTK inhibitors (BTKi), such as ibrutinib and acalabrutinib, and Bcl-2 inhibitor (Bcl-2i) venetoclax after long-term treatment in the clinic. Dysregulation of Bcl-2 and Bcl-X L, contributes to therapeutic resistance in MCL. AZD0466 is a novel and highly potent Bcl-2/X L dual inhibitor with active moiety AZD4320. Our preliminary data showed AZD4320 is potent in inhibiting cell viability of MCL cells (IC 50 = 1.6-78 nM). In this study, we assessed the combination efficacy of AZD4320/AZD0466 and acalabrutinib on preclinical MCL models.MethodsCell viability assay was performed to assess the in vitro efficacy of AZD4320 and acalabrutinib alone or in combination in a panel of ibrutinib/venetoclax-sensitive and -resistant MCL cell lines. Cell apoptosis assay was also performed to determine if AZD4320 and acalabrutinib enhanced cell death by cell apoptosis in MCL cell lines. Protein expression profiles of a panel of pro- and anti-apoptotic proteins and other relevant proteins were detected by immunoblotting. Since AZD4320 is limited in preclinical model due to physicochemical properties and dose limiting cardiovascular toxicity, AZD0466, the drug-dendrimer conjugate of AZD4320, was used for in vivo experiment. In vivo efficacy of AZD0466 (34 mg/kg, weekly, iv) and acalabrutinib (20 mg/kg, BID, oral) alone or in combination was evaluated using a Mino-venetoclax-R (Mino-R) cell xenograft model and a PDX model derived from an ibrutinib-CAR-T dual-resistant MCL patient.ResultsAZD4320 in combo with acalabrutinib inhibited cell proliferation synergistically in both ibrutinib/venetoclax-sensitive and -resistant cell lines (combination index = 0.17-0.93). Compared to vehicle or either single agent, the combination enhanced cell apoptosis by increasing pro-apoptotic markers cleaved caspase 3 and cleaved PARP. In the xenograft mouse model derived from venetoclax-resistant Mino-R cells, co-treatment of AZD0466 and acalabrutinib decreased tumor size significantly compared to vehicle (n = 5, p < 0.0001) or either single agent (n = 5, p = 0.0118 and 0.0070, respectively). Furthermore, in the PDX mouse model derived from a patient relapsed subsequently from ibrutinib and CAR T therapy, the combination of AZD0466 and acalabrutinib inhibited tumor growth compared to vehicle or either single agent. Acalabrutinib or AZD0466 improved survival compared with vehicle by 14 days or 32 days, respectively. Compared to Acalabrutinib or AZD0466, the combination therapy extended survival by 25 days and 7 days, respectively. All mice tolerated the treatment dose without any weight loss compared to the vehicle or either single agent group.ConclusionCompared to AZD4320/AZD0466 and acalabrutinib, combination therapy demonstrated anti-MCL synergy both in vitro and in vivo. These findings suggest that targeting Bcl-2/X L and BTK is promising to overcome multiple acquired resistance phenotypes, including CD19 CAR T-cell therapy. DisclosuresAndersen: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Cidado: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Wang: DTRM Biopharma (Cayman) Limited: Consultancy; BeiGene: Consultancy, Honoraria, Research Funding; Physicians Education Resources (PER): Honoraria; Anticancer Association: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; CAHON: Honoraria; The First Afflicted Hospital of Zhejiang University: Honoraria; Epizyme: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria, Research Funding; BGICS: Honoraria; Imedex: Honoraria; Clinical Care Options: Honoraria; Celgene: Research Funding; Genentech: Consultancy; Loxo Oncology: Consultancy, Research Funding; InnoCare: Consultancy, Research Funding; Molecular Templates: Research Funding; Lilly: Research Funding; VelosBio: Consultancy, Research Funding; BioInvent: Research Funding; Oncternal: Consultancy, Research Funding; OMI: Honoraria; Newbridge Pharmaceuticals: Honoraria; Scripps: Honoraria; Hebei Cancer Prevention Federation: Honoraria; Chinese Medical Association: Honoraria; Pharmacyclics: Consultancy, Research Funding; Juno: Consultancy, Research Funding; CStone: Consultancy; Bayer Healthcare: Consultancy; Miltenyi Biomedicine GmbH: Consultancy, Honoraria; Kite Pharma: Consultancy, Honoraria, Research Funding; Acerta Pharma: Consultancy, Honoraria, Research Funding; Dava Oncology: Honoraria; Moffit Cancer Center: Honoraria; Mumbai Hematology Group: Honoraria.

Precision Co-Targeting of the Thymic Stromal Lymphopoietin Receptor in Childhood CRLF2-Rearranged Acute Lymphoblastic Leukemia

Introduction : Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) is associated with high rates of chemoresistance and relapse. CRLF2 (cytokine receptor-like factor 2) rearrangements occur in 50% of Ph-like and 60% of Down Syndrome (DS)-associated ALL and induce constitutive JAK/STAT and other kinase signaling. Current clinical trials are studying chemotherapy with the JAK inhibitor ruxolitinib in patients with CRLF2-rearranged Ph-like ALL, but results are not yet known. While chimeric antigen receptor T-cell (CART) immunotherapies have induced remarkable remissions in children with relapsed/refractory B-ALL, approximately 50% of CD19CART-treated patients will relapse again, many with CD19 antigen loss. New therapies are needed to prevent relapse and overcome immunotherapeutic resistance.Methods : We previously developed CAR T cells targeting the thymic stromal lymphopoietin receptor (TSLPR; encoded by CRLF2) and demonstrated potent preclinical activity in Ph-like ALL models (Qin Blood 2015), which has led to a soon-to-open phase 1 clinical trial for patients with relapsed/refractory CRLF2-overexpressing ALL. In the current preclinical studies, we hypothesized that combinatorial targeting with bispecific TSLPRxCD19CART or TSLPRxCD22CART (Ross Cancer Res 2020) or with TSLPRCART + ruxolitinib will have superior activity against CRLF2-rearranged Ph-like and DS-ALL.Results : TSLPRCART treatment of CRLF2-rearranged ALL cell line (n=1) and patient-derived xenograft (PDX) models potently inhibited leukemia proliferation in vitro and in vivo and induced long-term ‘cure’ of xenograft mice. However, co-administration of TSLPRCART + ruxolitinib markedly diminished in vivo T cell numbers, blunted cytokine production, and facilitated leukemia relapse, which could be abrogated by delaying ruxolitinib. Importantly, ruxolitinib co-treatment prevented severe TSLPRCART-induced cytokine release syndrome (CRS) and animal death. Interestingly, ruxolitinib withdrawal led to return of T-cell functionality with re-detection of TSLPRCART in peripheral blood, induction of IFN-γ production, and leukemia clearance upon CRLF2+ ALL rechallenge (Figure 1).Conclusions: In these preclinical studies, we report potent activity of TSLPRCART in cell line (n=1) and PDX models of childhood CRLF2-rearranged Ph-like ALL (n=2) and DS-ALL (n=2) and, interestingly, deleterious effects of concomitant JAK inhibition upon CAR T cell functionality. We demonstrated that ruxolitinib co-administration impaired in vivo TSLPRCART-induced ALL cell killing but was also beneficial in protection against life-threatening cytokine release syndrome in co-treated animals. Importantly, TSLPRCART was not eliminated, only suppressed, by JAKi co-treatment with restoration of T cell functionality upon ruxolitinib removal and/or leukemia relapse/rechallenge studies. Ongoing studies are defining optimal TSLPRCART + ruxolitinib sequence(s) to maximize both anti-leukemia efficacy and potential CRS mitigation, as well as assessing in vivo efficacy of bispecific TSLPRCARTs in CRLF2-R Ph-like ALL and DS-ALL PDX models for future translation and clinical evaluation in next-generation trials. [Display omitted] DisclosuresFry: ElevateBio: Research Funding; Sana Biotechnology: Current Employment, Current equity holder in publicly-traded company. Tasian: Aleta Biotherapeutics: Consultancy; Kura Oncology: Consultancy; Gilead Sciences: Research Funding; Incyte Corporation: Research Funding.

Tafasitamab Plus Lenalidomide Versus Pola-BR, R2, and CAR T: Comparing Outcomes from RE-MIND2, an Observational, Retrospective Cohort Study in Relapsed/Refractory Diffuse Large B-Cell Lymphoma

Tafasitamab Plus Lenalidomide Versus Pola-BR, R2, and CAR T: Comparing Outcomes from RE-MIND2, an Observational, Retrospective Cohort Study in Relapsed/Refractory Diffuse Large B-Cell Lymphoma

Hospitalization and Healthcare Resource Use of Omidubicel Vs Cord Blood Transplantation for Hematological Malignancies in a Global Randomized Phase III Clinical Trial

IntroductionUmbilical cord blood (UCB) remains an important source of hematopoietic stem cells for patients, where no matched donor is available and for racial minorities. However, cord blood transplants have been associated with delayed hematopoietic recovery, prolonged hospitalization, and higher costs of transplant compared with other donor sources. Omidubicel is an advanced cell therapy that preserves stem cell function to optimize cell homing, engraftment, differentiation, and self-renewal and is manufactured from an appropriately HLA-matched single UCB unit for each patient. A recent phase III clinical trial (NCT02730299) reported that patients who received omidubicel experienced faster time to neutrophil engraftment, faster platelet recovery, reduced rates of infections and shorter hospitalization time than patients who received standard single (33%) or double (67%) UCB transplantation [Horwitz et al, Blood, 2021]. We report on an analysis of resource utilization including hospital length of stay, hospital care setting, visits by provider type, rates of transfusions and readmissions from the Phase III trial.MethodsThe Phase III clinical trial included patients aged 12-65 with hematological malignancies and eligible for an allogeneic transplant. The primary endpoint was time to neutrophil engraftment, with secondary endpoints of time to platelet engraftment, first grade 2/3 bacterial or fungal infections and days alive and out of hospital in the first 100 days. 125 patients were randomized in the study. We analyzed resource utilization data for patients treated with omidubicel (n=52) or UCB (n=56) (“as-treated population”) focusing on resource utilization within the first 100 days of transplantation. Summary statistics were compared between treatment arms, means and medians used to draw comparison and significance testing was performed.ResultsIn the Phase III clinical trial, omidubicel met its primary endpoint and secondary endpoints with statistical significance. The demographics and patient characteristics were overall well-balanced with slightly more males (52% vs 63%) and a lower median age (40 vs 36) in the UCB arm. The study population was diverse with 17.6% Black, 14.8% Asian, 14% Hispanic or Latino and 12% other/unknown. Most patients had AML (45%) or ALL (34.3%), with MDS, CML and lymphomas making up the rest of the study population. The disease risk index was high/very high in 35% of the patients and 24% of the patients had a Karnofsky/Lansky performance score of <90. The rapid hematopoietic recovery was supported by a reduced rate of infections. The rates of acute and chronic GVHD in the two arms were comparable.Within the first 100 days after transplant, omidubicel patients experienced shorter average total length of hospital stay than UCB recipients (mean 41.2 vs 50.8 days; p = 0.027) and more days alive and out of the hospital (mean 55.8 vs 43.7 days; p=0.023). 12% of patients on omidubicel arm died vs 16% on UCB arm before day 100. During the primary hospitalization (transplant to discharge), fewer omidubicel patients required intensive care unit (ICU) stay (9.6% vs 23.2%) and spent fewer days in the ICU (mean 0.4 vs 4.7 days; p =0.028) and the transplant unit (mean 25.3 vs 32.9 days; p =0.022) compared to UCB recipients. Omidubicel patients required fewer outpatient consultant visits and fewer outpatient non-consultant visits (X-rays, scans, biopsies etc.) and required fewer platelet or other transfusions (RBC, albumin, plasma, and factor product) within 100 days from transplant (Table 1).ConclusionsThis analysis shows that more rapid hematopoietic recovery in patients transplanted with omidubicel was associated with significantly shorter hospital length of stay and reduced healthcare resource use compared to UCB in the clinical trial. Although economic data were not collected as part of the clinical trial, the costs of providing transplantation care during the first 100 days are likely lower with omidubicel compared to UCB in the real-world setting, as hospital stay, outpatient visits, and blood product transfusions are among the major drivers of costs during this time period. [Display omitted] DisclosuresMajhail: Incyte Corporation: Consultancy; Anthem, Inc: Consultancy. Manghani: Gamida Cell, Inc.: Current Employment; Tricida, Inc.: Ended employment in the past 24 months. Sivaraman: Incyte Corporation: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Gamida Cell, Inc.: Current Employment. Galamidi-Cohen: Gamida Cell, Ltd: Current Employment. Maziarz: Bristol-Myers, Squibb/Celgene, Intellia, Kite: Honoraria; CRISPR Therapeutics: Consultancy; Artiva Therapeutics: Consultancy; Intellia: Honoraria; Omeros: Research Funding; Athersys: Other: Data and Safety Monitoring Board, Patents & Royalties; Incyte Corporation: Consultancy, Honoraria; Novartis: Consultancy, Other: Data and Safety Monitoring board, Research Funding; Allovir: Consultancy, Research Funding; Vor Pharma: Other: Data and Safety Monitoring Board.

A First-in-Class STAT3 Degrader KT-333 in Development for Treatment of Hematologic Cancers

Signal Transducer and Activator of Transcription 3 (STAT3) plays important roles in the transduction of signals from growth factors and cytokines in both normal and malignant cells. Upon activation, STAT3 controls expression of genes that regulate cell growth, survival, differentiation, stemness and cell-cell interactions. Aberrant activation of STAT3 has been observed in many cancers including lymphoma and leukemias through activating mutations, hyper-signaling through upstream regulators or loss of negative feedback regulation. Additionally, STAT3-mediated cross-talk in the tumor microenvironment results in suppression of immune surveillance compromising anti-tumor immunity.STAT3 has been historically considered “undruggable”. Heterobifunctional degraders that recruit endogenous E3 ligases to ubiquitinate substrate proteins leading to their degradation by the proteosome have emerged as a novel therapeutic modality with great potentials to drug undrugged protein targets. Here we introduce a first-in-class, potent and selective STAT3 degrader KT-333 that is being developed for the treatment of hematologic malignancies and solid tumors.KT-333 is a small molecule targeted protein degrader of STAT3 and was discovered by an iterative medicinal chemistry SAR campaign improving parameters such as potency, selectivity and ADME profile. It has high solubility in PBS buffer (103 mg/mL, pH7.4). low to moderate clearance in rat, dog and monkey, and moderate plasma half lives across pre-clinical species.KT-333 exhibits potent and selective degradation of STAT3 with DC 50 of 2.5 -11.8 nM in four anaplastic T cell lymphoma (ALCL) lines. Selective degradation of STAT3 over nearly 9000 proteins, including other STAT family members, was demonstrated by mass spectrometry in human PBMCs . Tumor cells expressing NPM-ALK fusion oncoproteins have activated STAT3 and dependency on STAT3 signaling for survival KT-333 treatment led to rapid apoptosis of these ALK+ALCL cells. To better understand the cellular responses to STAT3 degradation, time-course transcriptomic and proteomic analyses were performed using SU-DHL-1 cells treated with KT-333. Time-dependent changes in both mRNA and protein levels of STAT3-regulated genes and pathways were observed: at 8 h only STAT3 showed significant depletion, at 24 h canonical STAT3 downstream genes including SOCS3, IL-2RA and GRZMB showed modulation and at 48 h, pathways including interferon response and cell cycle were significantly enriched. A comparison of the transcriptomic and proteomic data sets showed high correlation. Furthermore, changes in mRNA and protein levels of bona fide STAT3 regulated targets showed a high degree of concordance between SU-DHL-1 cells and SU-DHL-1 xenograft tumors.Preclinical in vitro experiments have demonstrated that approximately 90% degradation of STAT3 for 48 h was sufficient to drive ALK+ ALCL lines into irreversible cell growth inhibition and death. In vivo xenograft studies of SU-DHL-1 and SUP-M2 ALCL models demonstrated dose-dependent tumor growth suppression. An indirect response model that linked exposure to target degradation was established to describe the relationship between exposure and target degradation in the tumor. Consistent with the in vitro data, PK-PD-efficacy analysis in the SU-DHL-1 xenograft model showed that tumor regression could be achieved with intermittent dosing schedules that achieved ~90% degradation of STAT3 for about 48 h over a weekly or bi-weekly dosing interval. . Based on preclinical ADME and PK/PD/efficacy relationship, KT-333 is predicted to drive tumor regression using weekly doses.In conclusion, we have identified a potent STAT3 degrader as development candidate that can be administered parenterally in the clinic on an intermittent dosing regimen that is predicted to be both efficacious and tolerated in STAT3-dependent hematologic malignancies. DisclosuresLiu: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Dixit: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Mayo: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Dey: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Yuan: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Karnik: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Walther: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Shi: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Sharma: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Rong: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Yang: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Gollerkeri: BEAM Therapeutics: Current Employment, Current equity holder in publicly-traded company; Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Gollob: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. DeSavi: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company.