Phase 1/2 Study of Nexi-001 Donor-Derived Multi-Antigen Specific CD8+ T Cells for the Treatment of Relapsed Acute Myeloid Leukemia (AML) after Allogeneic Hematopoietic Transplantation

Abstract Patients who relapse after allogeneic HCT have a poor prognosis and few effective treatment options. Responses to salvage therapy with donor lymphocyte infusions (DLI) are driven by a graft versus leukemia (GvL) effect. However, relapses and moderate to severe graft versus host disease (GVHD) are common. Therapies that increase the GvL effect without inducing GVHD are needed. The NEXI-001 study is a prospective, multicenter, open-label phase 1/2 trial designed to characterize the safety, immunogenic, and antitumor activity of the NEXI-001 antigen specific T-cell product. This product is a donor-derived non-genetically engineered therapy that consists of populations of CD8+ T cells that recognize HLA 02.01-restricted peptides from the WT1, PRAME, and Cyclin A1 antigens. These T cells consist of populations with key memory phenotypes, including stem-like memory, central memory, and effector memory cells, with a low proportion (<5%) of potentially allogeneic-reactive T-naïve cells. Patients enrolled into the first cohort of the dose escalation phase received a single infusion of 50 million (M) to 100M cells of the NEXI-001 product. Bridging anti-AML treatment was permitted during the manufacture of the cellular product with a wash-out period of at least 14 days prior to lymphodepletion (LD) chemotherapy (intravenous fludarabine 30 mg/m 2 and cyclophosphamide 300 mg/m 2) that was administered on Days -5, -4, and -3 prior to the infusion of the NEXI-001 product up to 72 hours later (Day1). Lymphocyte recovery to baseline levels occurred as early as three days after the NEXI-001 product infusion with robust CD4 and CD8 T cell reconstitution after LD chemotherapy. NEXI-001 antigen specific T cells were detectable in peripheral blood (PB) by multimer staining and were found to proliferate over time and to traffic to bone marrow. The phenotype composition of detectable antigen specific T cells at both sites was that of the infused product. T-cell receptor (TCR) sequencing assays revealed T cell clones in the NEXI-001 product that were not detected in PB of patients tested at baseline. These unique clones subsequently expanded in PB and bone marrow (BM) and persisted over time. Neutrophil recovery, decreased transfusion burden of platelets and red blood cells, and increased donor chimerism were observed. Decreases in myeloblasts and reduction in the size of an extramedullary myeloid sarcoma were suggestive of clinical activity. One patient, a 23-year- old with MRD+ disease at baseline, received two doses of 200M NEXI-001 cells separated by approximately 2 months. Following the first infusion, antigen specific CD8+ T cells increased gradually in PB to 9% of the total CD3+ T cell population just prior to the second infusion and were found to have trafficked to bone marrow. By Day 2 following the second infusion, which was not preceded by LD chemotherapy, the antigen specific CD8+ T cells again increased to 9% of the total CD3+ T cell population in PB and remained at ≥5% until the end of study visit a month later. The absolute lymphocyte count increased by 50% highlighting continued expansion of the NEXI-001 T cells. These cells also maintained significant Tscm populations. Treatment related adverse events, including infusion reactions, GVHD, CRS, and neurotoxicity (ICANS), have not developed in these patients who have received 50M to 200M T cells of the NEXI-001 product either as single or repeat infusions. In conclusion, these results show that infusion of the NEXI-001 product is safe and capable of generating a cell-mediated immune response with early signs of clinical activity. A second infusion is associated with increasing the level of antigen specific CD8+ T cells and their persistence in PB and BM. TCR sequencing and RNA Seq transcriptional profiling of the CD8+ T cells are planned, and these data will be available for presentation during the ASH conference. At least two cycles of 200M NEXI-001 cells weekly x 3 weeks of a 4-week cycle is planned for the next dose-escalation cohort. Early data suggest that the NEXI-001 product has the potential to enhance a GvL effect with minimal GVHD-associated toxicities. Disclosures Al Malki: Jazz Pharmaceuticals, Inc.: Consultancy; Neximmune: Consultancy; Hansa Biopharma: Consultancy; CareDx: Consultancy; Rigel Pharma: Consultancy. Vasu: Boehringer Ingelheim: Other: Travel support; Seattle Genetics: Other: travel support; Kiadis, Inc.: Research Funding; Omeros, Inc.: Membership on an entity's Board of Directors or advisory committees. Modi: MorphoSys: Membership on an entity's Board of Directors or advisory committees; Seagen: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding. Perales: Sellas Life Sciences: Honoraria; Novartis: Honoraria, Other; Omeros: Honoraria; Merck: Honoraria; Takeda: Honoraria; Karyopharm: Honoraria; Incyte: Honoraria, Other; Equilium: Honoraria; MorphoSys: Honoraria; Kite/Gilead: Honoraria, Other; Bristol-Myers Squibb: Honoraria; Celgene: Honoraria; Medigene: Honoraria; NexImmune: Honoraria; Cidara: Honoraria; Nektar Therapeutics: Honoraria, Other; Servier: Honoraria; Miltenyi Biotec: Honoraria, Other. Edavana: Neximmune, Inc: Current Employment. Lu: Neximmune, Inc: Current Employment. Kim: Neximmune, Inc: Current Employment. Suarez: Neximmune, Inc: Current Employment. Oelke: Neximmune, Inc: Current Employment. Bednarik: Neximmune, Inc: Current Employment. Knight: Neximmune, Inc: Current Employment. Varela: Kite: Speakers Bureau; Nexlmmune: Current equity holder in publicly-traded company, Honoraria, Membership on an entity's Board of Directors or advisory committees.

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Phase 1/2 Study of Nexi-002 Autologous Multi-Antigen-Specific CD8+ T Cells for the Treatment of Relapsed or Refractory Multiple Myeloma

Blood ◽

10.1182/blood-2021-152185 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2824-2824

Author(s):

Robert D Knight ◽

Myo Htut ◽

Juan C. Varela ◽

Andrew Kin ◽

Vineetha Edavana ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Phase 1 ◽

Cd8 T Cell ◽

Clinical Activity ◽

Cell Product ◽

Over Time

Abstract The NEXI-002 study is a prospective, multicenter, open-label phase 1/2 trial designed to characterize the safety, immunologic, and preliminary anti-myeloma activity of the NEXI-002 antigen specific CD8+ T cell product. Multiple myeloma (MM) is an incurable malignancy that occurs predominantly in older patients and is characterized by the growth of malignant plasma cells in the bone marrow. Despite substantial advances in therapy, virtually all patients relapse after treatment, emphasizing the unmet medical need for additional effective treatments. The NEXI-002 product is an autologous non-genetically engineered therapy of CD8+ T cells that recognize HLA 02.01-restricted peptides from the WT1, CD138, CS1, and NY-ESO-1 antigens. This T-cell product includes key memory phenotypes such as stem-like memory, central memory, and effector memory cells. Eligible patients have relapsed or refractory multiple myeloma (RRMM) who have received at least three prior lines of treatment that included at least an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 agent. Three patients were enrolled into the Safety Evaluation phase and received a single infusion of 80 million (M) to 100M cells of NEXI-002 product. In this phase of the study the primary endpoint is safety and secondary endpoints include expansion, persistence, and trafficking of the NEXI-002 cells. Bridging anti-MM treatment was permitted during the manufacture of the cellular product with a wash-out period of at least 14 days prior to lymphodepletion (LD) chemotherapy (intravenous fludarabine 30 mg/m 2 and cyclophosphamide 300 mg/m 2), which was administered on Days -5, -4, and -3 prior to the infusion of the NEXI-002 product up to 72 hours later (Day1). Treatment-related adverse events, including infusion reactions, events that prolong hospitalization post infusion, CRS, and neurotoxicity (ICANS) have not developed in these patients who received the NEXI-002 product. Lymphocyte recovery to baseline levels occurred within a few days after the infusion of the NEXI-002 product, demonstrating robust CD4 and CD8 T cell reconstitution following LD chemotherapy. NEXI-002 antigen specific T cells were detected in peripheral blood (PB) by multimer staining and proliferated over time and trafficked to the bone marrow (BM). The phenotype composition of detectable antigen specific T cells at both sites maintained that of the infused product. These NEXI-002 T cells persisted in PB and BM during follow-up. T-cell receptor (TCR) sequencing assays revealed T cell clones in the NEXI-002 product that were not detected in PB of patients tested at baseline. These clones subsequently expanded and persisted over time in the PB and BM. In conclusion, these results show that infusion of the NEXI-002 product is safe, well tolerated, and capable of generating a cell-mediated immune response that may lead to clinical activity. RNA Seq transcriptional profiling of the CD8+ T cells is planned. Additional patients have recently received NEXI-002 infusions and the trial will continue to be expanded to gain additional safety, immunologic, and clinical activity experience. Disclosures Knight: Neximmune, Inc: Current Employment. Varela: Nexlmmune: Current equity holder in publicly-traded company, Honoraria, Membership on an entity's Board of Directors or advisory committees; Kite: Speakers Bureau. Edavana: Neximmune, Inc: Current Employment. Lu: Neximmune, Inc: Current Employment. Kim: Neximmune, Inc: Current Employment. Suarez: Neximmune, Inc: Current Employment. Oelke: Neximmune, Inc: Current Employment. Bednarik: Neximmune, Inc: Current Employment.

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Vecabrutinib Is Efficacious In Vivo in a Preclinical CLL Adoptive Transfer Model

Blood ◽

10.1182/blood-2018-99-116664 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1868-1868 ◽

Cited By ~ 1

Author(s):

Billy Michael Chelliah Jebaraj ◽

Annika Scheffold ◽

Eugen Tausch ◽

Judith A. Fox ◽

Pietro Taverna ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Research Funding ◽

Tumor Burden ◽

Transfer Model ◽

Advisory Committees

Abstract B cell receptor signaling (BCR) in chronic lymphocytic leukemia (CLL) drives tumor cell proliferation and survival. Inhibition of Bruton's tyrosine kinase (BTK), a key enzyme in the BCR pathway, has proved to be efficacious even in poor-risk and chemo-refractory patients. However resistance to the BTK inhibitor ibrutinib has been shown to emerge in a subset of CLL patients. Of importance, the C481S BTK mutation conferred resistance by preventing the covalent binding of ibrutinib to its target cysteine 481 in BTK. Vecabrutinib (formerly known as SNS-062, a succinate salt) is a novel, highly potent, next generation noncovalent BTK inhibitor which demonstrated biochemical and cellular activity against C481S BTK mutant in vitro. However, the efficacy of vecabrutinib and its impact on the T-cell microenvironment has not been studied in in vivo preclinical CLL models. In the present study, the efficacy of vecabrutinib was investigated using the Eµ-TCL1 adoptive transfer model. Mice were randomized to treatment with either 40mg/kg vecabrutinib succinate, twice daily by oral gavage (n=6) or vehicle control (n=6). The mice were sacrificed after 2 weeks of treatment and changes in tumor burden as well as alterations in T-cell microenvironment were analysed in detail. Treatment with vecabrutinib decreased tumor burden as observed by a significant decrease in WBC count (36.5 vs. 17.1 giga/L; P=0.002), spleen weight (median 0.56g vs. 0.31g; P=0.005) and liver weight (median 1.5g vs. 1.2g; P=0.005) compared to vehicle treatment. Correspondingly, the CD5+ CD19+ tumor cells were significantly decreased in blood (P=0.002) and spleen (P=0.002) while no significant difference was observed in bone marrow (P=0.818) upon treatment with vecabrutinib. Since BTK inhibition is known to reshape the tumor microenvironment, we studied the impact of vecabrutinib specifically on T-cell subsets. Firstly, no difference in the proportions of CD4 or CD8 expressing T-cells was observed in mice treated with vehicle or vecabrutinib. However, of interest, the percentage of CD4+ CD25+ FoxP3+ regulatory T cells (Tregs) were significantly decreased upon treatment with vecabrutinib in peripheral blood (P=0.026) and spleen (P=0.009). The decrease in Tregs was due to reduced proliferation of these cells upon exposure to the drug as measured by Ki-67 staining. Also, the Tregs expressing the maturation and activation markers such as CD103 and GITR were significantly decreased in blood and spleen upon drug treatment. Further, we analysed the changes in CD8 T-cell subsets following treatment with vecabrutinib. Treatment with the drug resulted in expansion of the CD127+ CD44- naïve CD8 T-cells in blood, bone marrow and spleen (all P values 0.002) while the CD127+ CD44+ memory CD8 T-cells were significantly decreased in bone marrow and spleen (all P values 0.009). Also, the CD127low CD44int-hi effector CD8 T-cells were decreased in blood (P=0.004), bone marrow (P=0.004) and spleen (P=0.002) upon vecabrutinib treatment. Therefore, vecabrutinib treatment did not alter the percentage of CD4+ and CD8+ T cells in mice however, significant changes in the subset composition of the CD4 and CD8 T cells were observed. Lastly, to analyse the impact of vecabrutinib on survival, a cohort of mice (n=12) were transplanted with 5 million splenic tumor cells isolated from Eµ-TCL1 transgenic mice. After allowing for engraftment, the mice were randomized to treatment with the drug (n=6) or vehicle (n=6). Of note, the mice treated with the drug showed a significant increase in survival (median 35 days from transplant; P<0.001) compared to treatment with vehicle (median 28 days). In summary, vecabrutinib was efficacious in vivo in a preclinical CLL adoptive transfer model, decreasing tumor burden in different organs and significantly improving survival. Treatment with the drug altered the T-cell architecture in vivo. Of interest, the immunosuppressive Tregs, which protect the tumor from immune surveillance were decreased in various tissue compartments; however, a decrease in the effector CD8 T cells might impact anti-tumor immunity if there is a consistent effect upon drug treatment. Vecabrutinib antitumor activity and effects on T-cell populations in vivo in this preclinical CLL model are intriguing, merits further investigation and supports the ongoing phase 1b/2 study in patients with previously treated B-lymphoid malignancies (NCT03037645). Disclosures Tausch: AbbVie: Consultancy, Other: Travel grants; Celgene: Consultancy, Other: Travel grants; Gilead: Consultancy, Other: Travel grants. Fox:Sunesis Pharmaceuticals: Employment; Amphivena Therapeutics: Employment. Taverna:Sunesis Pharmaceuticals: Employment. Stilgenbauer:Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffmann La-Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genzyme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmcyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Phase 1 Study of CART-Ddbcma, a CAR-T Therapy Utilizing a Novel Synthetic Binding Domain for the Treatment of Subjects with Relapsed and Refractory Multiple Myeloma

Blood ◽

10.1182/blood-2020-142931 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 2-2

Author(s):

Matthew J Frigault ◽

Michael R. Bishop ◽

Elizabeth K. O'Donnell ◽

Noopur S. Raje ◽

Allegra Mondillo ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Phase 1 ◽

Private Company ◽

Advisory Committees ◽

Car T Cells ◽

Car T

Introduction: Chimeric Antigen Receptor (CAR) T cell therapies directed against B-cell maturation antigen (BCMA) have demonstrated compelling clinical activity and manageable safety in subjects with relapsed and refractory Multiple Myeloma (RRMM). These CAR T cells encode humanized or murine scFvs, or camelid heavy chain antibody fragments with CD3-zeta in combination with 41BB or CD28 co-stimulatory domains. In contrast, CART-ddBCMA is an anti-BCMA investigational CAR T cell therapy encoding a non-scFv, synthetic binding domain targeting BCMA with a 4-1BB costimulatory motif and CD3-zeta T cell activation domain. The binding domain is a small stable protein comprising 73 amino acids engineered to reduce the risk of immunogenicity. CART-ddBCMA is being studied as part of a Master Phase 1 Cell Therapy protocol for RRMM and is a first-in-human clinical study to assess the safety, pharmacokinetics, immunogenicity, efficacy, and duration of effect. Methods: ARC-101 (NCT04155749), ARM 1 (CART-ddBCMA) is a Phase 1, multi-center, open label, dose escalation trial enrolling approximately 12 subjects with RRMM who have received ≥ 3 prior regimens, including a proteasome inhibitor, an immuno-modulatory agent, and a CD38 antibody or are triple-refractory. There is no prescreening or requirement for BCMA expression on tumor cells. Peripheral blood mononuclear cells are collected via leukapheresis and sent to a central facility for selection, transduction, and expansion on the CliniMACS Prodigy® system. The drug product is cryopreserved and undergoes release testing prior to being returned to the site for infusion. Subjects undergo lymphodepletion with fludarabine (30 mg/m2) and cyclophosphamide (300 mg/m2) daily for 3 days, then receive CART-ddBCMA as a single infusion. Planned dose levels are 100, 300, and 900 x 106 CAR+ T cells. The primary outcome measure is incidence of adverse events (AEs), including dose-limiting toxicities (DLTs). Additional outcome measures are quality and duration of clinical response assessed according to the IMWG Uniform Response Criteria for MM, evaluation of minimal residual disease (MRD), progression-free and overall survival, and quantification of CAR+ cells in blood. Results: As of July 1, 2020, 4 subjects (median age 73.5 [min;max 73 to 75]) were enrolled and 4 received CART-ddBCMA. Median follow-up after CART-ddBCMA infusion was 100 days (min:max 9 to 142 days), 3 subjects were evaluable for initial safety and clinical response and 1 subject was pending assessment. All subjects received a dose of 100 x 106 CAR+ T cells±20%, median drug product CAR+ expression was 76% (min:max 72-78%) of total CD3+ T cells. Subjects had a median of 5 (min;max 5 to 7) prior lines of therapy and one had prior autologous stem cell transplant; one had high-risk cytogenetics. All 4 subjects had previously received Bort/Len/Car/Pom/Dara and 2 were penta-refractory. Three subjects had high tumor burden, with 95, 95, and 70% bone marrow plasma cells pre-infusion, respectively. Three subjects developed Grade 2 cytokine release syndrome (CRS) and 1 subject developed Grade 2 ICANS. These adverse effects resolved quickly after intervention; 3 subjects received tocilizumab and 2 received steroids (dexamethasone). All 3 evaluable subjects have demonstrated clinical response per IMWG criteria: currently 1 sCR (MRD-10-4), 1 sCR, 1 sCR (MRD-10-6). MRD negative results were obtained by next-generation sequencing (Adaptive clonoSEQ), 1 subject did not have baseline bone marrow involvement. Extramedullary disease resolved in three subjects. CAR+ T cell expansion during the first 30 days was observed in evaluable subjects by ddPCR. No post treatment ADA were detected in the first 3 subjects, through M1. Conclusions: In the initial cohort receiving 100 x 106 CAR+ T cells of CART-ddBCMA, no subjects experienced severe CRS and/or ICANs. Early efficacy results are encouraging, with all 3 evaluable subjects demonstrating deep clinical responses of sCR, with 2 MRD negative bone marrow responses at 1 month. No evidence of ADA has been detected to date. These data are encouraging in a small group of elderly subjects who did not initially receive autologous transplant following induction therapy. Subjects continue to be enrolled and treated. Additional subjects, and longer follow-up will establish whether treatment with CART-ddBCMA results in durable CAR+ T responses. Disclosures Frigault: Celgene: Consultancy; Novartis: Consultancy, Research Funding; Arcellx: Consultancy; Gilead/Kite: Consultancy, Research Funding. Bishop:Kite: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Honoraria, Speakers Bureau; Autolus: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; CRSPPR Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Speakers Bureau. O'Donnell:Celgene: Consultancy. Raje:Celgene: Consultancy. LeFleur:Arcellx: Current Employment, Current equity holder in private company. Buonato:arcellx: Current Employment, Current equity holder in private company. Edwards:arcellx: Current Employment, Current equity holder in private company. Richman:arcellx: Current equity holder in private company. Polianova:arcellx: Current Employment, Current equity holder in private company. Sabatino:Arcellx: Current equity holder in private company. Currence:Arcellx: Current Employment, Current equity holder in private company. Shen:Arcellx: Current Employment, Current equity holder in private company. Quigley:Arcellx: Current Employment, Current equity holder in private company. Maus:arcellx: Consultancy, Research Funding; kite: Consultancy, Research Funding; Novartis: Consultancy, Research Funding.

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Final Results of Phase 1/1b Study of Tenalisib, Dual PI3K δ/γ Inhibitor in Patients with Relapsed/Refractory T-Cell Lymphoma

Blood ◽

10.1182/blood-2019-123954 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2831-2831 ◽

Cited By ~ 1

Author(s):

Swaminathan P. Iyer ◽

Brad M. Haverkos ◽

Jasmine Zain ◽

Radhakrishnan Ramchandren ◽

Mary Jo Lechowicz ◽

...

Keyword(s):

T Cell ◽

Adverse Events ◽

Board Of Directors ◽

Dose Escalation ◽

Safety Profile ◽

Research Funding ◽

Cell Lymphoma ◽

Phase 1 ◽

Clinical Activity ◽

Advisory Committees

Introduction: Tenalisib (RP6530) is a novel, highly specific, dual PI3K δ/γ inhibitor with nano-molar inhibitory potency at the enzyme and cellular level. PI3K plays a critical role in T-cell development and activation and several studies have validated the PI3K-AKT pathway as a potential therapeutic target in T cell lymphomas. Preliminary results of the ongoing Phase 1/1b T-cell lymphoma (TCL) study demonstrated an acceptable safety profile with encouraging clinical activity in relapsed/refractory TCL (Oki, ASCO 2018 and Iyer, ASH 2018). We now present the final results of the study (NCT02567656). Methods: This study comprised of four-dose escalation cohorts, followed by two dose expansion cohorts at MTD enrolling 20 patients each in PTCL and CTCL cohorts. Patients had histologically confirmed TCL, ECOG PS ≤2, and had received ≥1 prior therapy. Patients received Tenalisib [200 mg BID-800 mg BID (fasting), 800 mg (fed only)] orally until progression or unacceptable toxicity. The primary objectives were to determine the MTD and pharmacokinetic profile. The secondary objective was to evaluate overall response rate (ORR) and duration of response. Responses were evaluated for PTCL and CTCL based on IWG criteria (Cheson 2007) and mSWAT respectively. Adverse events were graded according to CTCAE v4.03. Results: Fifty-eight patients were enrolled in study, 19 in dose escalation and 39 in dose expansion (28 PTCL and 30 CTCL). Median number of prior therapies was 4 (range, 1-15). Safety assessment of 58 patients receiving at least one dose of Tenalisib demonstrated an acceptable safety profile. Treatment related Grade≥3 AEs were elevated ALT/AST (21%), rash (5%), and hypophosphatemia (3%). These events were reversible and managed by withholding study drug. Additionally, in few patients (N=9), steroids were used to manage elevated ALT/AST. There were six treatment related serious adverse events, none of these led to fatal outcome. At end of the study, four (3 CTCL; 1 PTCL) patients who completed minimum 8 cycles of therapy were rolled over to a compassionate use study (NCT03711604) and were followed up. Efficacy assessments demonstrated an ORR of 46% (3 CR and 13 PR) and clinical benefit rate (CR+PR+SD) of 77%. Subset efficacy analysis showed an ORR in PTCL of 47% (3 CR; 4 PR) and in CTCL of 45% (9 PR). The median time to initial response was 1.8 months and was similar in both sub-types. The overall median DOR was 4.91 months (range 0.9-26.6); in PTCL patients the DOR was 6.53 months, (range: 0.97-21.0) and 3.8 months (range: 1.67-25.67) in CTCL patients. In 3 PTCL patients who achieved CR, the median DOR was 19.5 months (range 7.5-21). Conclusion: Tenalisib demonstrated promising clinical activity and an improved safety profile in patients with relapsed/ refractory TCL. Currently, a phase I/II combination study to further evaluate safety and efficacy with romidepsin is ongoing in this target population. Disclosures Iyer: Arog: Research Funding; Bristol-Myers Squibb: Research Funding; Novartis: Research Funding; Seattle Genetics, Inc.: Research Funding; Genentech/Roche: Research Funding; Incyte: Research Funding. Zain:Spectrum: Consultancy; Seattle Genetics: Consultancy. Korman:Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Glaxo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Immune Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kyowa: Research Funding; Leo: Research Funding; Menlo: Research Funding; Merck: Research Funding; Novartis: Consultancy, Honoraria, Speakers Bureau; Pfizer: Research Funding; Principia: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Prothena: Research Funding; Regeneron: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Rhizen: Research Funding; Sun: Honoraria, Membership on an entity's Board of Directors or advisory committees; Syntimmune: Research Funding; UCB: Research Funding; Valeant: Honoraria, Membership on an entity's Board of Directors or advisory committees; Eli Lilly: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Dermira: Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Routhu:Rhizen Pharmaceuticals S.A.: Employment. Barde:Rhizen Pharmaceuticals S.A.: Employment. Nair:Rhizen Pharmaceuticals S.A.: Employment. Huen:Galderma Inc: Research Funding; Glaxo Smith Kline Inc: Research Funding; Rhizen Pharmaceuticals: Research Funding; Innate Pharmaceuticals: Research Funding.

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CD4+ T Cell Fate in Multiple Myeloma

Blood ◽

10.1182/blood-2018-99-117674 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4494-4494

Author(s):

Rachel Elizabeth Cooke ◽

Jessica Chung ◽

Sarah Gabriel ◽

Hang Quach ◽

Simon J. Harrison ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Research Funding ◽

Flow Cytometric Analysis ◽

Advisory Committees ◽

Mitochondrial Mass ◽

Flow Cytometric

Abstract The average incidence of multiple myeloma (MM) is in the 7th decade that coincides with the development of immunosenescence and thymic atrophy, meaning that lymphocyte recovery after lymphopenia-inducing therapies (most notably autologous stem cell transplant, ASCT) is largely reliant on homeostatic proliferation of peripheral T cells rather than replenishing the T cell pool with new thymic emigrants. We have previously shown that there is a significant reduction in circulating naïve T cells with a reciprocal expansion of antigen-experienced cells from newly diagnosed MM (NDMM) to relapsed/refractory disease (RRMM). This results in a reduced TCR repertoire and the accumulation of senescence-associated secretory phenotype cytotoxic T cells, which maintain the ability to produce IFNγ but lose proliferative potential. A reduction in CD4:8 ratio is also a characteristic finding in MM with disease progression, which can be explained by high IL-15 levels in lymphopenic states that preferentially drive expansion of CD8+ memory T cells. We wanted to further evaluate what changes were occurring in the CD4+ T cell population with disease progression in MM. We analyzed paired peripheral blood (PB) samples from patients with NDMM and RRMM, and compared with age-matched normal donors (ND). In the NDMM cohort, we examined T cells from PB samples at baseline, after 4 cycles of lenalidomide and dexamethasone (len/dex), and after ASCT; and in the RRMM cohort samples from baseline and after 6 cycles of len/dex. We firstly confirmed in flow cytometric analysis of T cells at serial intervals in NDMM patients that the reduction in circulating naïve T cells and in CD4:8 ratio occurs post ASCT and does not recover by time of last follow-up. We next utilised RNA-seq to analyse differences in CD4+ T cells from NDMM, RRMM and ND. CD4+ T cells from RRMM showed downregulation of cytosolic ribosomal activity but maintenance of mitochondrial ribosomal activity and significant upregulation of pathways involved with calcium signalling. To this end, we evaluated mitochondrial biogenesis and metabolic pathways involved with mitochondrial respiration. Flow cytometric analysis of mitochondrial mass showed a marked increase in RRMM compared with ND, in keeping with a shift towards memory phenotype. Key rate-limiting enzymes in fatty acid β-oxidation (CPT1-A, ACAA2 and ACADVL) were all significantly increased in RRMM compared with ND. To analyse whether these cells were metabolically active, we also measured mitochondrial membrane potential and reactive oxygen species (ROS), gating on cells with high mitochondrial mass. Mitochondrial membrane potential was significantly increased in RRMM compared with ND, although ROS was reduced. The significance of this is not clear, as ROS are not only implicated in cell senescence and activation-induced cell death, but are also positively involved in tyrosine kinase and PI3K-signalling pathways. PD-1 has been shown to play a role in transitioning activated CD4+ T cells from glycolysis to FAO metabolism, and elevating ROS in activated CD8+ T cells. We analysed PD-1 expression on T cells in RRMM and at treatment intervals in NDMM (as described earlier). The proportion of CD4+ and CD8+ T cells expressing PD-1 was increased 4-6 months post-ASCT and remained elevated in CD4+ T cells 9-12 months post-ASCT, but normalised to baseline levels in CD8+ T cells. Increased PD-1 expressing CD4+ T cells was also evident in RRMM patient samples. This may suggest that in the lymphopenic state, PD-1 expression enhances longevity in a subset of CD4+ T cells by promoting reliance on mitochondrial respiration; however, their ability to undergo homeostatic proliferation is impaired. In CD8+ T cells, high PD-1 expression may lead to cell death via ROS accumulation, and these cells do not persist. ASCT remains a backbone of myeloma treatment in medically fit patients. However, this leads to significant permanent defects in the T cell repertoire, which may have unintended adverse outcomes. Additionally, T cells post-ASCT may not be metabolically adequate for the production of CAR-T cells, nor respond to checkpoint blockade therapies. Disclosures Quach: Amgen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Sanofi Genzyme: Research Funding; Janssen Cilag: Consultancy. Harrison:Janssen-Cilag: Other: Scientific advisory board. Prince:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees.

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The Innate Immune Sensor Sting Promotes Donor CD8+ T Cell Activation and Recipient APC Death Early after Preclinical Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽

10.1182/blood-2019-130197 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3202-3202

Author(s):

Cameron S. Bader ◽

Henry Barreras ◽

Casey O. Lightbourn ◽

Sabrina N. Copsel ◽

Dietlinde Wolf ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

T Cell Activation ◽

Cd8 T Cells ◽

Research Funding ◽

Cell Activation ◽

Cd8 T Cell ◽

Advisory Committees ◽

Hematopoietic Stem

Graft-versus-host disease (GVHD) remains a significant cause of morbidity and mortality in patients receiving allogeneic hematopoietic stem cell transplants (aHSCTs). Pre-HSCT conditioning typically consists of irradiation and drug administration resulting in the death of rapidly dividing cells and release of endogenous danger signals. These molecules drive the activation of antigen presenting cells (APCs) and the differentiation of allo-reactive donor T cells, leading to damage of particular host tissues characteristic of GVHD. Cell death following conditioning has promoted the hypothesis that sensors of cytoplasmic DNA damage in GVHD target tissues contribute to pro-inflammatory cytokine production. We identified a role for Stimulator of Interferon Genes (STING), an innate immune sensor, in GVHD using pre-clinical MHC-matched unrelated donor (MUD) aHSCT models. Here we show that STING rapidly promotes donor CD8+ T cell activation and recipient APC death early after aHSCT. To assess STING involvement immediately post-HSCT, cytokine mRNA expression was examined 48 hrs after transplant of MUD C3H.SW bone marrow (BM) + T cells into irradiated B6 wildtype (WT) or STING-/- recipients. Colon tissue from STING-/- recipients had >2x reduction in IFNβ, TNFα and IL-6 mRNA vs WT. MUD STING-/- HSCT recipients also experienced decreased weight loss, GVHD scores and skin pathology 6 wks post-HSCT vs WT. Double chimerism studies showed that the absence of STING in non-hematopoietic cells was responsible for GVHD amelioration. Conversely, a single dose of the highly specific STING agonist DMXAA given in vivo increased IFNβ, TNFα and IL-6 mRNA expression in WT, but not STING-/-, colon tissue 48 hrs after transplant and increased GVHD scores and lethality post-HSCT. Post-transplant cytoxan treatment abolished the ability of DMXAA to augment GVHD, supporting the notion that STING signaling increases donor T cell activation during aHSCT. To evaluate the potential impact of STING in the clinical setting, we transplanted C3H.SW BM + T cells into mice homozygous for a murine homologue of a human allele associated with diminished STING activity (STINGHAQ/HAQ) and found that these mice also exhibited diminished GVHD. Interestingly, our findings that STING deficiency ameliorates GVHD in MUD aHSCT contrasts to reported observations that STING deficiency can exacerbate GVHD after MHC-mismatched (MMUD) aHSCT (Fischer J, et al, Sci. Transl. Med. 2017). Since CD4+ and CD8+ T cells are central in MMUD and MUD GVHD, respectively, we hypothesized that STING's effect on the predominant T cell subset in each model may explain these seemingly paradoxical results in STING-/- vs WT recipients. Therefore, we transplanted MMUD BALB/c BM + CD8+ T cells into B6-WT and STING-/- mice and found that - in contrast to MMUD recipients of combined CD4+ and CD8+ T cells - STING-/- recipients developed lower GVHD clinical scores, reduced skin pathology and had lower frequencies of activated T cells 8 wks post-HSCT vs WT, supporting a role for STING in the promotion of CD8+ T cell-mediated GVHD. Next, we investigated if recipient APCs played a role in STING's enhancement of CD8+ T cell-mediatedGVHD. We found that STING-/- mice had greater frequencies and numbers of recipient splenic CD11b+CD11c+ APCs 1 day after MMUD B6 into BALB/c aHSCT (Fig. A). BALB/c-STING-/- APCs also expressed reduced MHC class I protein levels (Fig. B). Moreover, STING-/- recipient spleens contained lower numbers of donor CD8+ T cells producing IFNγ and TNFα (Fig. C). These data support the hypothesis that STING contributes to early activation of donor CD8+ T cells and elimination of recipient APCs. Next, to identify if the loss of host MHC II+ APCs affected subsequent donor CD4+ T cell activation, B6-Nur77GFP transgenic donor T cells were used to explicitly monitor T cell receptor signaling. Consistent with increased numbers of host MHC II+ APCs in the spleens of STING-/- recipients 1 day post-aHSCT, we found greater frequencies and numbers of donor Nur77GFP CD4+ T cells expressing GFP, CD69 and IFNγ in STING-/- spleens 6 days after transplant (Fig. D). In summary, our studies demonstrate that STING plays an important role in regulating aHSCT and provide one potential mechanism by which STING could promote CD8+ T cell-mediated GVHD yet diminish CD4+-mediated GVHD. Overall, our studies suggest this pathway can provide a target for new therapeutic strategies to ameliorate GVHD. Disclosures Blazar: BlueRock Therapeutics: Membership on an entity's Board of Directors or advisory committees; Childrens' Cancer Research Fund: Research Funding; KidsFirst Fund: Research Funding; Tmunity: Other: Co-Founder; Kamon Pharmaceuticals, Inc: Membership on an entity's Board of Directors or advisory committees; Regeneron Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Five Prime Therapeutics Inc: Co-Founder, Membership on an entity's Board of Directors or advisory committees; Magenta Therapeutics and BlueRock Therapeuetics: Membership on an entity's Board of Directors or advisory committees; Fate Therapeutics, Inc.: Research Funding; RXi Pharmaceuticals: Research Funding; Alpine Immune Sciences, Inc.: Research Funding; Abbvie Inc: Research Funding; Leukemia and Lymphoma Society: Research Funding. Levy:Heat Biologics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pelican Therapeutics: Consultancy, Research Funding.

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Early Mycosis Fungoides Lesions with Increased CD3-CD4+ Histiocytes Are Associated with Dyslipidemia and Use of Statins

Blood ◽

10.1182/blood.v126.23.4609.4609 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4609-4609

Author(s):

Chee Won Oh ◽

Carlos Torres-Cabala ◽

Mikyoung Chang ◽

Madeleine Duvic

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Research Funding ◽

Skin Lesions ◽

Medication History ◽

Advisory Committees ◽

History Of ◽

Skin Biopsies

Abstract Background The term "histiocyte" includes cells of the monocyte/macrophage series as antigen processing cells and the Langerhans cell/DC series as antigen-presenting cells. At least three DC subsets exist in skin: two expressing either CD1a or CD14 are dermal and Langerhans cells expressing CD1a are epidermal. Since the phenotype of histiocytic cells is typically CD3-CD4+, an estimation of the CD4+ histiocytic population can be made by comparing the numbers of CD3+ T cells with CD4+ cells. Programmed Cell Death 1 (PD-1) is an inhibitory receptor expressed on T cells, B cells, and some myeloid cells. During chronic antigen exposure, expression of PD-1 is sustained. Statins, inhibitors of cholesterol biosynthesis, are immunomodulatory agents acting on T cells and DCs, but their effects on skin immunology are unknown. Objectives To investigate whether infiltrates of CD3-CD4+histiocytes in early mycosis fungoides (MF) lesional skin biopsies are associated with any other factors, including history of medication and to reveal their histopathological pattern. Methods From Jan to Dec 2014, we identified cases of early MF from the clinic in which CD4+ cells exceeded CD3+ cells with biopsies to identify increased histiocytic population. Exclusion criteria included Sézary syndrome, granulomatous MF, T cell receptor beta monoclonality, abnormal T cell populations by flow cytometry, retinoid treatment, and progression of disease after treatment (n=12). Clinical and laboratory findings were retrospectively reviewed. Skin biopsies stained for H&E, CD3, CD4, CD7, and CD8 were reviewed. In 3 cases with paraffin blocks available, immunohistochemical stains for CD68, CD1a, CD163, PD-1, and PD-1 ligand PD-L1 were done. Results Clinical manifestations of early MF were pink scaly patches (9/12), capillaritis (2/12), and annular erythema - like patches (1/12). Eleven also had an increased monocytes in peripheral blood. All cases had a medication history of taking statins (atorvastatin 5/12; simvastatin 2/12; rosuvastatin 1/12) for dyslipidemia (hypercholesterolemia 7/12; both hypercholesterolemia and hypertriglyceridemia 3/12). In 9/12, symptoms persisted after MF treatment. A lichenoid or superficial perivascular lymphohistiocytic infiltration was observed in skin lesions. Focal basal vacuolization was found in all 12 patients. Upper dermal perivascular extravasation of RBCs suggesting vasculopathy was also found in 12/12 cases. All twelve cases showed predominant CD4+ T cells compared to CD8+ T cells in dermis and the CD4+ T cells were more prominent in dermis rather than in epidermis. CD7+ T cells were preserved (3/12) or partially lost (9/12). In all 3 cases, macrophage markers CD68 and CD163 were positive in dermal infiltrates. CD1a+ DCs were increased in both epidermis and dermis in all 3/3. Only one case of three showed PD1/PD-L1+ T cells in dermis. Discussion and Conclusion All our cases had a medication history of statins for dyslipidemia. Of interest, skin biopsies showed a vasculopathy previously reported during high-dose atorvastatin treatment (Tehrani et al, 2013) and infiltration of CD4/CD8+ T cells, CD1a+DCs and CD163/CD68+ macrophages. We hypothesize that statins or dyslipidemia in early MF were associated with cutaneous T cell immune reaction. In support of our hypothesis that dyslipidemia is associated with histiocytosis, we found a report of nine cases of granulomatous pigmented purpuric dermatosis with concurrent hyperlipidemia (Battle et al, 2015). Cholesterol induces monocytosis and M1 macrophages in mice. One study showed that predominant migration of mature CD1a+ DC is associated with release of IL-12p70 and efficient expansion of Th 1 cells and functional CD8+ T cells. On the contrary, IL-10 up-regulates migration of immature CD14+ DC, expression of the M2 macrophage marker CD163, poor expansion of CD4+ and CD8+ T cells, and skewing of Th responses conducive to expression of PD-L1. We cannot know whether skin lesions are secondary to hyperlipidemia or to treatment with statins. Although M1 and M2 macrophages can be distinguished by diverse markers, none of these antigens are suitable for single-marker identification by immunohistochemistry in paraffin embedded tissue blocks. Further study of the cutaneous effect and immunologic mechanisms leading to increased expression of DCs and T cell dysfunction after statin medication is necessary. Disclosures Duvic: Oncoceutics: Research Funding; Therakos: Research Funding, Speakers Bureau; Huya Bioscience Int'l: Consultancy; Tetralogics SHAPE: Research Funding; Innate Pharma: Research Funding; Cell Medica Ltd: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees; MiRagen Therapeutics: Consultancy; Soligenics: Research Funding; Allos (spectrum): Research Funding; Array Biopharma: Consultancy; Spatz Foundation: Research Funding; Rhizen Pharma: Research Funding; Eisai: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kyowa Hakko Kirin, Co: Membership on an entity's Board of Directors or advisory committees, Research Funding.

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NME-2 Protein Functions as a Tumour Associated Antigen in HLA-A2+ Cells and Is Over Expressed in CML Via a Bcr/Abl Dependent Post Transcriptional Mechanism.

Blood ◽

10.1182/blood.v114.22.3266.3266 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3266-3266

Author(s):

Sabine Tschiedel ◽

Melanie Adler ◽

Karoline Schubert ◽

Annette Jilo ◽

Enrica Mueller ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Cell Response ◽

Research Funding ◽

Kinase Activity ◽

T Cell Response ◽

Advisory Committees

Abstract Abstract 3266 Poster Board III-1 Introduction: NmE2 (Nm23-H2, NDP kinase B) is one of a family of proteins that catalyze the transfer of gamma-phosphate between nucleoside-triphosphates and diphosphates. The two major family members, NmE1 and NmE2 are strongly implicated in the control of differentiation, proliferation, migration and apoptosis via interactions which are often independent of their kinase activity, NmE2 being a transcriptional activator of the c-myc gene. We recently identified NmE2 as a tumour associated, HLA-A32+ restricted, antigen in a patient with CML and found the protein (but not the mRNA) to be generally over expressed in CML but not in other haematological malignancies. We also detected a specific T-cell response in peripheral blood cells of a patient 5 years after transplantation. This identifies NmE2 as a potential target for both molecular and immunotherapy of CML. However, the development of immunotherapeutic approaches will depend on the ability of NmE2 to function as a tumour antigen in common HLA backgrounds. The aims of this study were firstly to investigate the antigenicity of NmE2 in the HLA-A2 background (which accounts for more than 50% of the Caucasian population), and secondly to characterise the regulatory relationship between Bcr/Abl and NmE2 using a cell line model of CML. Materials and Methods: 5 nonameric NmE2 peptides with predicted anchor amino acids for HLA-A2 were loaded at concentrations of 10μM separately onto HLA-A2 expressing antigen presenting cells. Elispot Assays were carried out with CD8+ MLLCs (for the identification of antigenic peptides) or CD8+ cells isolated directly from a CML patient at different time points after HCT. Ba/F3 cells stably expressing wild type and mutant forms of Bcr/Abl were treated with imatinib and nilotinib (0 – 10 μM) for 48h. Bcr/Abl activity was assessed by FACS using antibodies specific for the phosphorylated forms of CrkL and Stat5. NmE2 and c-Myc protein were detected by immunocytochemistry and Western blotting with specific antibodies [Santa Cruz, clones L-16 and 9E10 respectively]. Levels of nme2 and c-myc mRNA were determined by quantitative real time PCR. Results: Full length NmE2 protein and 2 of 5 HLA-A2 anchor-containing peptides tested (NmE2132–140 and NmE2112–120) were specifically recognized by the HLA-A2+ CD8+ MLLC, demonstrating the antigenicity of NmE2 in the HLA-A2 background in vitro. Furthermore, while CD8+ T-cells from a transplanted HLA-A2+ CML patient showed little or no specific reactivity in the first 10 months after HCT, a distinct reactivity (up to 0.6 % NmE2 reactive CD8+ T cells) became apparent at later stages, consistent with the development of an immune response against NmE2-expressing cells in vivo. The patient remained negative for bcr/abl transcripts throughout this period. BA/F3 Bcr/Abl cells expressed increased levels of NmE2 protein (but not mRNA) compared to the parent BA/F3 line. Interestingly, treatment with imatinib or nilotinib reduced NmE2 protein expression in BA/F3 Bcr/Abl, but not in cells expressing Bcr/Abl mutants resistant to the respective inhibitors. Treatment of BA/F3 Bcr/Abl cells with the PI3K inhibitor Ly294002 resulted in reduced Bcr/Abl activity and a corresponding reduction in both c-Myc and NmE2 protein levels, without affecting mRNA levels. Conclusion: The over expression of NmE2 is closely linked to Bcr/Abl kinase activity, the predominant level of regulation being post-transcriptional and dependent on PI-3K activity. The NmE2 protein is restricted by HLA-A2 as well as by HLA-A32. The development of an NmE2-specific T-cell response in a CML patient after stem cell transplantation suggests that NmE2 functions as a tumour antigen in HLA-A2+ patients in vivo and may be relevant to the long term immune control of CML. NmE2 is therefore a promising candidate for the development of new immunotherapeutic strategies for the treatment of CML. Disclosures: Lange: BMS: Honoraria; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Niederwieser:BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Research Funding.

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Preliminary Clinical Results from a Phase 1 Study of ACTR707 in Combination with Rituximab in Subjects with Relapsed or Refractory CD20+ non-Hodgkin Lymphoma

Blood ◽

10.1182/blood-2019-125995 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1587-1587

Author(s):

Ian W. Flinn ◽

Jason R. Westin ◽

Jonathon B. Cohen ◽

Luke P. Akard ◽

Samantha Jaglowski ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Dose Escalation ◽

Research Funding ◽

Phase 1 ◽

Advisory Board ◽

Phase 1 Study ◽

Advisory Committees ◽

Clinical Responses

Background: The Antibody-Coupled T-cell Receptor (ACTR) platform is an autologous engineered T-cell therapy that combines the cell-killing ability of T cells and the tumor-targeting ability of co-administered antibodies to exert potent antitumor immune responses. ACTR707 comprises the extracellular domain of CD16 linked to a CD3ζ signaling domain and a CD28 co-stimulatory domain. ACTR707 is in clinical development in combination with rituximab (NCT03189836) or trastuzumab (NCT03680560). Here we present clinical findings from the dose escalation phase of Study ATTCK-20-03, an ongoing, multicenter, phase 1 study of ACTR707+rituximab in subjects with relapsed or refractory (R/R) CD20+ NHL. Methods: The primary objectives of this first-in-human study are to evaluate the safety of the combination of ACTR707 and rituximab and to determine a recommended phase 2 dose (RP2D). Other objectives include evaluating antitumor activity and ACTR T-cell persistence. Subjects must have CD20+ NHL that is R/R after prior treatments, which must include anti-CD20 antibody-containing chemotherapy. Subjects receive lymphodepleting chemotherapy (cyclophosphamide and fludarabine) for 3 days, followed by rituximab and a single dose of ACTR707. Additional doses of rituximab are administered q3w until disease progression, unacceptable toxicity, or Investigator decision. The study includes a dose escalation phase (increasing doses of ACTR707 with fixed dose of rituximab at 375 mg/m2 q3w) and an expansion phase at the RP2D. Results: Six subjects received ACTR707 at Dose Level 1 (DL1; 23-38×106 ACTR+ T cells), 3 subjects at DL2 (30-50×106 ACTR+ T cells), and 5 subjects at DL3 (45-55×106 ACTR+ T cells). The majority of the subjects were diagnosed with DLBCL (93%) and had refractory disease (71%), defined as progressive disease as the best response to any prior treatment or relapse <1 year post autologous stem cell transplant. In DL1 through DL3, as of 27 May 2019, there were no dose-limiting toxicities, AEs of cytokine release syndrome (CRS), serious or severe neurologic AEs, or AEs leading to deaths on treatment. TEAEs reported in >2 subjects, regardless of causality or grade, included neutropenia, thrombocytopenia, anemia, febrile neutropenia, pyrexia, cough, constipation, diarrhea, nausea, and vomiting. SAEs considered possibly related to ACTR707 were febrile neutropenia (n=2) and cytopenia (n=1). ACTR707 expansion generally reached peak levels within 1 to 2 weeks after administration. All subjects with complete response (CR) up to 1 year had detectable ACTR at the last timepoint evaluated. Higher ACTR707 CD8:CD4 T-cell ratios were associated with clinical responses. Clinical activity was reported across DL1 through DL3, with an overall response rate of 64% including durable complete responses (CRs), with one subject in CR for 387+ days (Table 1). Conclusions: Data available from DL1 through DL3 of ACTR707+rituximab suggest that clinical responses can be achieved without severe T cell-mediated toxicities (eg, CRS and neurotoxicity) that have been reported with other autologous T-cell products. Dose escalation continues at a target dose of 80×106 ACTR+ T cells; enrollment in DL4 (n=6) was recently completed. Updated data, including identified correlates of clinical outcomes, will be presented for DL1 through DL4. Disclosures Flinn: TG Therapeutics, Trillum Therapeutics, Abbvie, ArQule, BeiGene, Curis, FORMA Therapeutics, Forty Seven, Merck, Pfizer, Takeda, Teva, Verastem, Gilead Sciences, Astra Zeneca (AZ), Juno Therapeutics, UnumTherapeutics, MorphoSys, AG: Research Funding; AbbVie, Seattle Genetics, TG Therapeutics, Verastem: Consultancy; TG Therapeutics, Trillum Therapeutics, Abbvie, ArQule, BeiGene, Curis, FORMA Therapeutics, Forty Seven, Merck, Pfizer, Takeda, Teva, Verastem, Gilead Sciences, Astra Zeneca (AZ), Juno Therapeutics, UnumTherapeutics, MorphoSys, AG: Research Funding; Acerta Pharma, Agios, Calithera Biosciences, Celgene, Constellation Pharmaceuticals, Genentech, Gilead Sciences, Incyte, Infinity Pharmaceuticals, Janssen, Karyopharm Therapeutics, Kite Pharma, Novartis, Pharmacyclics, Portola Pharmaceuticals: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding. Westin:Genentech: Other: Advisory Board, Research Funding; Janssen: Other: Advisory Board, Research Funding; Kite: Other: Advisory Board, Research Funding; Unum: Research Funding; Curis: Other: Advisory Board, Research Funding; Juno: Other: Advisory Board; MorphoSys: Other: Advisory Board; 47 Inc: Research Funding; Celgene: Other: Advisory Board, Research Funding; Novartis: Other: Advisory Board, Research Funding. Cohen:Genentech, Inc.: Consultancy, Research Funding; Takeda Pharmaceuticals North America, Inc.: Research Funding; Gilead/Kite: Consultancy; LAM Therapeutics: Research Funding; UNUM: Research Funding; Hutchison: Research Funding; Astra Zeneca: Research Funding; Lymphoma Research Foundation: Research Funding; ASH: Research Funding; Bristol-Meyers Squibb Company: Research Funding; Seattle Genetics, Inc.: Consultancy, Research Funding; Janssen Pharmaceuticals: Consultancy. Akard:Celgene: Speakers Bureau; Novartis: Speakers Bureau; Takeda: Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau; Gilead: Speakers Bureau. Jaglowski:Juno: Consultancy, Other: advisory board; Kite: Consultancy, Other: advisory board, Research Funding; Unum Therapeutics Inc.: Research Funding; Novartis: Consultancy, Other: advisory board, Research Funding. Sachs:Unum Therapeutics Inc.: Employment. Ranger:Unum Therapeutics Inc.: Employment. Harris:Unum Therapeutics Inc.: Employment. Payumo:Unum Therapeutics Inc.: Employment. Bachanova:Celgene: Research Funding; Gamida Cell: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; GT Biopharma: Research Funding; Kite: Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; Novartis: Research Funding.

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Single-Cell Analysis of the Classical Hodgkin Lymphoma Immune Environment Reveals a Clonally-Expanded CD8+ T Cell Population with a Cytotoxic Phenotype

Blood ◽

10.1182/blood-2020-137171 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 40-41

Author(s):

Jovian Yu ◽

Xiufen Chen ◽

James Godfrey ◽

Girish Venkataraman ◽

Sonali M. Smith ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Single Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Research Funding ◽

Immune Cell ◽

Clonal Expansion ◽

Advisory Committees ◽

Cell Clusters

Introduction: Classical Hodgkin lymphoma (cHL) is characterized by a robust and complex immune cell infiltrate and the rare presence of malignant Hodgkin-Reed-Sternberg (HRS) cells. At the genetic level, HRS cells recurrently acquire alterations that lead to defective antigen presentation (β2 microglobulin mutations) and mediate T cell dysfunction (PD-L1 copy gains/amplifications) in order to subvert host immune surveillance. The clinical relevance of PD-L1 protein over-expression in cHL is clear, as response rates to PD-1 blockade therapy are extremely high among patients with relapsed/refractory (r/r) disease. Despite its remarkable efficacy, the cells that mediate response to anti-PD-1 therapy in cHL remain undefined. Recent analyses have highlighted a possible role for CD4+ T cells in mediating the clinical activity of anti-PD-1 therapy in cHL. CD4+ T cells significantly outnumber CD8+ T cells in cHL lesions and are more frequently juxtaposed to HRS cells in situ. Furthermore, HLA class II expression on HRS cells predicted higher complete response rates to PD-1 blockade therapy in r/r cHL patients. However, a candidate T cell population capable of specific reactivity to antigens expressed by HRS cells has yet to be identified. This information is critical as such T cells might be functionally reinvigorated to mediate HRS cell elimination following PD-1 blockade therapy. In order to address this key knowledge gap, we analyzed data at single cell (sc) resolution using paired RNA and T cell receptor (TCR) sequencing in 9 diagnostic cHL and 5 reactive lymph node (RLN) specimens. Methods: Sequencing was performed using the 10x Genomics Chromium Single Cell 5' Gene Expression and V(D)J workflows. B-cell depletion of each sample was achieved using CD19 microbeads and negative selection to enrich T cell populations. Reads were analyzed and aligned with CellRanger (v3.1.0) and Seurat (v3.2.0) was used to conduct clustering by a shared nearest neighbor (SNN) graph on scRNA data. TCR sequencing data was integrated using scRepertoire (v1.0.0). Results: A detailed map of the immune cell states in cHL was created using scRNA-seq (10X) data on 79,085 cells from 9 cHL (52,602 cells) and 5 RLN samples (26,484 cells) expressing a total of 21,421 genes (mean 5649 cells/sample; mean 2849 mRNA reads/cell). Dimensionality reduction and unsupervised graph-based clustering revealed 21 distinct cell type and activation state clusters, including T cells, NK cells, macrophages, and dendritic cells (Fig 1A-B). A cluster identifying HRS cells was not observed, consistent with a recently published report. Ten T cell clusters were identified (47,573 cells), including naive- and memory-like T cells, effector/cytotoxic CD8+ T cells, regulatory T cells, and T follicular helper cells. Unexpectedly, a putative exhausted T cell cluster was not clearly observed. The relative contributions of cHL and RLNs cases to these clusters are shown in Fig 1C. Paired TCR sequencing was available for 23,943 cells. Overall TCR diversity was lower among cHL samples compared to RLN specimens (Fig 1D). In cHL samples, modest clonal expansion within regulatory T cell and memory CD4+ T cell clusters was observed, but the most striking clonal expansion occurred among cells assigned to effector/cytotoxic CD8+ T cell clusters - a finding not observed in most RLN specimens (Fig 1E). Clonally-expanded effector/cytotoxic CD8+ T cells displayed high expression of granzymes (GZMA, GZMH, GZMK), cytokines (TNF, IFNG) and chemokines (CCL4/CCL5), and modest expression of exhaustion markers (PDCD1, ENTPD1, HAVCR2, ITGAE), contrasting with data from single-cell analyses of solid tumors. Clonal expansion of effector/cytotoxic CD8+ T cells was particularly robust in EBV-positive cHLs, likely due to recognition of viral-derived epitopes displayed on HRS cells (Fig 1F). Phenotypic and functional validation of key immune cell clusters in cHL specimens using spectral cytometry is underway and will be reported at the meeting. Conclusions: For the first time, our data have unveiled the nature of the T cell repertoire in cHL at single cell resolution. Our results reveal a recurrent pattern of clonal expansion within effector CD8+ cells, which may be the HRS antigen-specific T cells that mediate response to PD-1 blockade. This hypothesis requires confirmation through similar analyses of pre- and on-treatment biopsies of cHL patients receiving anti-PD-1 therapy. Disclosures Godfrey: Gilead: Research Funding; Merck: Research Funding; Verastem: Research Funding. Venkataraman:EUSA Pharma: Speakers Bureau. Smith:Janssen: Consultancy; BMS: Consultancy; TG Therapeutics: Consultancy, Research Funding; Genentech/Roche: Consultancy, Other: Support of parent study and funding of editorial support, Research Funding; Karyopharm: Consultancy, Research Funding; FortySeven: Research Funding; Pharmacyclics: Research Funding; Acerta: Research Funding; Celgene: Consultancy, Research Funding. Kline:Kite/Gilead: Speakers Bureau; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Verastem: Membership on an entity's Board of Directors or advisory committees, Research Funding.

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