Blocking JAK1/JAK2 While Sparing JAK3 Not Only Prevents GvHD but Also Promotes Damaged Tissue Repair

The therapeutic benefits of allogeneic hematopoietic stem cell transplantation (allo-HSCT) are primarily derived from graft-versus-leukemia (GvL) that is mediated by mature T cells in donor grafts. Unfortunately, graft-versus-host disease (GvHD) results from immune reactions of these same donor T cells against host tissues and organs after allo-HSCT. Due to this strong association between GvHD and the beneficial GvL, our lab and others have been working on developing effective therapeutic strategies to selectively prevent and treat GvHD without abrogating GvL. Recently we have reported that pharmacologic inhibition of Janus kinases 1/2 (JAK1/JAK2) prevents GvHD by blocking IFNGR and IL6R signaling. Although baricitinib (BARI) and ruxolitinib (RUX) are both JAK1/JAK2 inhibitors with similar potency, BARI was found to be superior to RUX in prevention of GvHD in our mouse models of allo-HSCT. One of our proposed mechanistic pathways by which BARI prevents GvHD is via a robust increase in regulatory T cells (Tregs) which play a pivotal role in controlling GvHD. Since the proliferation and survival of Tregs are mediated through the IL2-JAK1/JAK3-STAT5 signaling pathway and that RUX is a more JAK3 inhibitor, we hypothesized that sparing JAK3 by BARI is critical for this increase of Tregs. To test this hypothesis, we administered BARI to allo-HSCT recipient mice with or without JAK3-specific inhibitor and monitored them for GvHD signs. The mice treated with BARI and iJAK3 had significantly lower Tregs and overall survival rates compared to the mice treated with BARI alone. This data suggests that BARI prevents GvHD by retaining JAK3, thereby increasing Tregs. We have also previously reported that BARI treats established GvHD. However, the mechanisms by which BARI reverses ongoing GvHD remain unclear. Consequently, we hypothesized that BARI not only modulates immune cell functions as we previously reported, but also promotes restoration of GvHD damaged tissues. To test our hypothesis, we delayed the administration of BARI until mice developed clinically apparent GvHD and treated them starting on days 10, 17, or 24 after allo-HSCT. Despite this latency, the day 10 group showed significantly better overall survival (p<0.001, n=14) and lower histopathological grades (p<0.001, n=5) in comparison with all other groups (Fig. A). Since the gastrointestinal (GI) tract is the one of most frequently diagnosed and severely damaged GvHD target organs, we tested the possible mechanistic pathways by which BARI reverses GvHD in the GI tract. We found that Paneth cells and intestinal stem cells which are both involved in maintaining the intestinal barrier integrity are substantially increased in day 10 (p<0.0001, n=13) and 17 (p<0.001, n=29) groups compared to the vehicle control (Fig. B). To understand the molecular mechanisms underlying BARI-mediated reversal of established GvHD, we treated human intestinal organoids with BARI and RUX. Upon observing an increased proliferation in organoids treated with BARI and RUX, we then performed RNA-seq analyses on them to determine the specific genes that are differentially regulated by the treatment of BARI and RUX. Thirteen genes were found to be significantly upregulated in the RUX and BARI treated samples and three of these genes (TFF1, ABCB1, and IGFBP3) have been shown to be positively associated with EGFR signaling while negatively associated with TNFR signaling. Once we confirmed the expression levels of these genes in the human organoids using real-time PCR, we then generated an in vitro established GvHD model by treating mouse intestinal organoids with inflammatory cytokines (IFNγ, TNFα, and IL-1β). Two days later, we treated these organoids with BARI and RUX to evaluate expressions of IGFBP3, TFF1 and ABCB1 (Fig. C). We found that BARI significantly upregulates expression of TFF1, ABCB1, and IGFBP3 RNA levels in those cytokine damaged intestinal organoids compared to RUX. Collectively, these data suggest that BARI possibly reverses established GvHD by promoting damaged tissue repair by activating EGFR signaling while inhibiting inflammation and crypt apoptosis by TNFR1 signaling through TFF1, IGFBP3, and ABCB1. Lastly, the increase of Tregs by sparing JAK3 and the upregulation of these three genes in BARI-treated groups may explain the superiority of BARI over RUX in both prevention and treatment of GvHD. Figure Disclosures DiPersio: Karyopharm Therapeutics: Consultancy; RiverVest Venture Partners Arch Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amphivena Therapeutics: Consultancy, Research Funding; Celgene: Consultancy; Incyte: Consultancy, Research Funding; Macrogenics: Research Funding, Speakers Bureau; WUGEN: Equity Ownership, Patents & Royalties, Research Funding; Magenta Therapeutics: Equity Ownership; Cellworks Group, Inc.: Membership on an entity's Board of Directors or advisory committees; Bioline Rx: Research Funding, Speakers Bureau; NeoImmune Tech: Research Funding. Choi:Daewoong Pharmaceuticals Co., Ltd: Consultancy.

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Final Analysis of Overall Survival from the Phase 3 Panorama 1 Trial of Panobinostat Plus Bortezomib and Dexamethasone Versus Placebo Plus Bortezomib and Dexamethasone in Patients with Relapsed or Relapsed and Refractory Multiple Myeloma

Blood ◽

10.1182/blood.v126.23.3026.3026 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3026-3026 ◽

Cited By ~ 5

Author(s):

Jesús F. San-Miguel ◽

Vania T.M. Hungria ◽

Sung-Soo Yoon ◽

Meral Beksac ◽

Meletios A. Dimopoulos ◽

...

Keyword(s):

Multiple Myeloma ◽

Overall Survival ◽

Board Of Directors ◽

Research Funding ◽

Final Analysis ◽

Employment Equity ◽

Phase 3 ◽

Advisory Committees ◽

Equity Ownership ◽

Study Therapy

Abstract Introduction: Panobinostat is a potent pan-deacetylase inhibitor (pan-DACi) that targets key aberrations in multiple myeloma (MM) cell biology, including epigenetics and protein metabolism. In the phase 3 clinical trial PANORAMA 1, panobinostat in combination with bortezomib and dexamethasone (PAN-BTZ-Dex) led to a statistically significant and clinically relevant increase in progression-free survival of approximately 4 months compared with that with placebo plus bortezomib and dexamethasone (Pbo-BTZ-Dex). Further analyses of patient outcomes by prior treatment demonstrated that the magnitude of PFS benefit was greatest among patients who received at least 2 prior regimens, including bortezomib and an immunomodulatory drug (IMiD; PAN-BTZ-Dex [n = 73]: 12.5 months [95% CI, 7.3-14.0 months]; Pbo-BTZ-Dex [n = 74]: 4.7 months (95% CI, 3.7-6.1 mo; HR 0.47 [95% CI, 0.32-0.72]). These data supported the regulatory approvals of PAN-BTZ-Dex for the treatment of patients with multiple myeloma who received at least 2 prior regimens, including bortezomib and an IMiD. Here we present the final analysis of overall survival (OS) for the entire patient population and among patients who received at least 2 prior regimens, including bortezomib and an IMiD. Methods: The study design for the PANORAMA 1 trial was described previously (San-Miguel. Lancet Oncol. 2014;15:1195-206). The key secondary endpoint was OS. As of June 29, 2015, the 415 events required to conduct the final analysis of OS had been observed. Kaplan-Meier estimation was utilized for OS analyses for the entire population (N = 768), the pre-specified subgroup of patients who received prior bortezomib and IMiD (n = 193), and patients who received at least 2 prior regimens including bortezomib and an IMiD (n = 147). Results: The median OS of patients who received PAN-BTZ-Dex in the overall population was 40.3 months (95% CI, 35.0-44.8 months) vs 35.8 months (95% CI, 29.0-40.6 months) for the Pbo-BTZ-Dex arm with HR 0.94 [95% CI, 0.78-1.14], P = .5435 (Fig 1A). The percentage of patients in each arm who received post-study therapy was 37.7% in the PAN-BTZ-Dex arm and 48.8% in the Pbo-BTZ-Dex arm. The median OS of patients who received at least 2 prior lines, including bortezomib and an IMiD, was 25.5 months (95% CI, 19.6-34.3 months) in the PAN-BTZ-Dex arm vs 19.5 months (95% CI, 14.1-32.5 months) in the Pbo-BTZ-Dex arm (Fig. 1B). The proportion of patients in this subgroup who received post-study therapy was 35.6% in the PAN-BTZ-Dex arm and 66.2% in the Pbo-BTZ-Dex arm. Conclusion: For the overall PANORAMA 1 study population, patients in the PAN-BTZ-Dex arm demonstrated an increase in median OS of 4.5 months vs patients in the Pbo-BTZ-Dex arm, but this result was not statistically significant (P = .5435). Median OS was also slightly longer for the PAN-BTZ-Dex arm among the more heavily pretreated subgroup of patients who received at least 2 prior regimens, including bortezomib and an IMiD. A higher percentage of patients on the Pbo-BTZ-Dex arm received post-study therapy vs the PAN-BTZ-Dex arm, which may have confounded the OS results. In summary, PAN-BTZ-Dex demonstrates statistically significant increases in PFS vs Pbo-BTZ-Dex in patients with relapsed or relapsed and refractory MM; however, this did not translate to a statistically significant increase in OS. Future trials will plan to focus on further optimization of dose and schedule of panobinostat and bortezomib to improve outcome, as well as novel combinations with other agents, including IMiDs and next-generation proteasome inhibitors. Figure 2. Figure 2. Disclosures Beksac: Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Consultancy, Speakers Bureau. Dimopoulos:Janssen: Honoraria; Janssen-Cilag: Honoraria; Onyx: Honoraria; Amgen: Honoraria; Genesis: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Jedrzejczak:Onconova: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Siritanaratkul:Pfizer: Research Funding; Roche: Research Funding; Novartis: Research Funding; Janssen-Cilag: Research Funding. Schlossman:Millennium: Consultancy. Hou:Novartis: Membership on an entity's Board of Directors or advisory committees. Moreau:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: 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; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Lonial:Bristol-Myers Squibb: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Onyx: Consultancy, Research Funding; Celgene: Consultancy, Research Funding. Sopala:Novartis Pharma: Employment, Equity Ownership. Bengoudifa:Novartis: Employment. Corrado:Novartis: Employment, Equity Ownership. Richardson: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; Novartis: Membership on an entity's Board of Directors or advisory committees; Millennium Takeda: Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Membership on an entity's Board of Directors or advisory committees.

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CD200 Is a Stem Cell-Specific Immunosuppressive Target in AML

Blood ◽

10.1182/blood-2018-99-114818 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2768-2768

Author(s):

Shelley Herbrich ◽

Keith Baggerly ◽

Gheath Alatrash ◽

R. Eric Davis ◽

Michael Andreeff ◽

...

Keyword(s):

Gene Expression ◽

Flow Cytometry ◽

T Cells ◽

Stem Cell ◽

Board Of Directors ◽

Research Funding ◽

Advisory Committees ◽

Cd200 Receptor ◽

Blast Cells ◽

Equity Ownership

Abstract Acute myeloid leukemia (AML) stem cells (LSC) are an extremely rare fraction of the overall disease (likely <0.3%), largely quiescent, and capable of both long-term self-renewal and production of more differentiated leukemic blasts. Besides their role in disease initiation, they are also hypothesized as the likely source of deadly, relapsed leukemia. Due to the quiescent nature of the LSCs, they are capable of evading the majority of chemotherapeutic agents that rely on active cell-cycling for cytotoxicity. Therefore, novel therapeutic approaches specifically engineered to eradicate LSCs are critical for curing AML. We previously introduced a novel bioinformatics approach that harnessed publically available AML gene expression data to identify genes significantly over-expressed in LSCs when compared to their normal hematopoietic stem cell (HSC) counterparts (Herbrich et al Blood 2017 130:3962). These datasets contain gene expression arrays on human AML patient samples sorted by leukemia stem, progenitor, and blast cells (with normal hematopoietic cell subsets for comparison). We have since expanded our statistical model to identify targets that are both significantly overexpressed in AML LSCs when compared to HSC as well as LSCs compared to their corresponding, more differentiated blast cells. Instead of traditional methods for multiple testing corrections, we looked at the intersection of genes that met the above criteria in 3 independently generated datasets. This resulted in a list of 30 genes, 28 of which appear to be novel markers of AML LSCs. From this list, we first chose to focus on CD200, a type-1 transmembrane glycoprotein. CD200 is broadly expressed on myeloid, lymphoid, and epithelial cells, while the CD200 receptor (CD200R) expression is strictly confined to myeloid and a subset of T cells. CD200 has been shown to have an immunosuppressive effect on macrophages and NK cells and correlates with a high prevalence FOXP3+ regulatory T cells (Coles et al Leukemia 2012; 26:2146-2148). Additionally, CD200 has been implicated as a poor prognostic marker in AML (Damiani et al Oncotarget 2015; 6:30212-30221). To date, we have screened 20 primary AML patient samples by flow cytometry, 90% of which are positive for CD200. Expression is significantly enriched in the CD34+/CD123+ stem cell compartment. To examine the role of CD200 in AML, we established two in vitro model systems. First, we used CRISPR/Cas9 to knockout the endogenous CD200 protein in Kasumi-1. Further, we induced CD200 in the OCI-AML3 cell line that had no expression at baseline. Both cell lines did not express the CD200 receptor before or after manipulation, negating any autocrine signaling. In both systems, CD200 manipulation did not affect the proliferation rate or viability of the cells. To examine the immune function of CD200 in AML, we performed a series of mixed lymphocyte reactions. We cultured normal human peripheral blood mononuclear cells (PBMCs) with the CD200+ or CD200- cells from each line both. Cells were incubated in the culture media for 4-48 hours before being harvested and measured by flow cytometry for apoptosis or intracellular cytokine production. The presence of CD200 on the cell surface reduced the rate of immune-specific apoptosis among these leukemia cells. The difference in cell killing was most likely attributable to a CD200-specific suppression of CD107a, a surrogate marker or cytotoxic activity. In the OCI-AML3 model, PBMCs co-cultured with CD200+ cells produced approximately 40% less CD107a when compared to the CD200- co-culture. Additionally, we characterized our new cell lines using RNA sequencing. By comparing the CD200+ to the CD200- cells within each line, we observed that CD200+ cells significantly downregulate genes involved in defining an inflammatory response as well as genes regulated by NF-κB in response to TNFα. This indicates that CD200 may have an undiscovered intrinsic role in suppressing the immune microenvironment of AML LSCs. In conclusion, we have expanded our novel bioinformatics approach for robustly identifying AML LSC-specific targets. Additionally, we have shown that one of these markers, CD200, has a potential role as a stem cell-specific immunosuppressive target by reducing immune-mediated apoptosis and transcriptionally suppressing inflammatory cell processes. We are extending our study to explore CD200 in primary patient samples using a CD200-blocking antibody. Disclosures Andreeff: SentiBio: Equity Ownership; Amgen: Consultancy, Research Funding; Oncolyze: Equity Ownership; Reata: Equity Ownership; United Therapeutics: Patents & Royalties: GD2 inhibition in breast cancer ; Jazz Pharma: Consultancy; Astra Zeneca: Research Funding; Aptose: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Patents & Royalties: MDM2 inhibitor activity patent, Research Funding; Eutropics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Oncoceutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy. Konopleva:Stemline Therapeutics: Research Funding.

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Development and Evaluation of a Human Single Chain Variable Fragment (scFv) Derived Bcma Targeted CAR T Cell Vector Leads to a High Objective Response Rate in Patients with Advanced MM

Blood ◽

10.1182/blood.v130.suppl_1.742.742 ◽

2017 ◽

Vol 130 (Suppl_1) ◽

pp. 742-742 ◽

Cited By ~ 1

Author(s):

Eric L Smith ◽

Sham Mailankody ◽

Arnab Ghosh ◽

Reed Masakayan ◽

Mette Staehr ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Employment Equity ◽

Advisory Committees ◽

Car T Cells ◽

Car T Cell ◽

Car T ◽

Equity Ownership

Abstract Patients with relapsed/refractory MM (RRMM) rarely obtain durable remissions with available therapies. Clinical use of BCMA targeted CAR T cell therapy was first reported in 12/2015 for RRMM, and based on small numbers, preliminary results appear promising. Given that host immune anti-murine CAR responses have limited the efficacy of repeat dosing (Turtle C. Sci Trans Med 2016), our goal was to develop a human BCMA targeted CAR T cell vector for clinical translation. We screened a human B cell derived scFv phage display library containing 6x1010 scFvs with BCMA expressing NIH 3T3 cells, and validated results on human MM cell lines. 57 unique and diverse BCMA specific scFvs were identified containing light and heavy chain CDR's each covering 6 subfamilies, with HCDR3 length ranges from 5-18 amino acids. 17 scFvs met stringent specificity criteria, and a diverse set was cloned into CAR vectors with either a CD28 or a 4-1BB co-stimulatory domain. Donor T cells transduced with BCMA targeted CAR vectors that conveyed particularly desirable properties over multiple in vitro assays, including: cytotoxicity on human MM cell lines at low E:T ratios (>90% lysis, 1:1, 16h), robust proliferation after repeat antigen stimulation (up to 700 fold, stimulation q3-4d for 14d), and active cytokine profiling, were selected for in vivo studies using a marrow predominant human MM cell line model in NSG mice. A single IV injection of CAR T cells, either early (4d) or late (21d) after MM engraftment was evaluated. In both cases survival was increased when treated with BCMA targeted CAR T cells vs CD19 targeted CAR T cells (median OS at 60d NR vs 35d p<0.05). Tumor and CAR T cells were imaged in vivo by taking advantage of luciferase constructs with different substrates. Results show rapid tumor clearance, peak (>10,000 fold) CAR T expansion at day 6, followed by contraction of CAR T cells after MM clearance, confirming the efficacy of the anti-BCMA scFv/4-1BB containing construct. Co-culture with primary cells from a range of normal tissues did not activate CAR T cells as noted by a lack of IFN release. Co-culture of 293 cells expressing this scFv with those expressing a library of other TNFRSF or Ig receptor members demonstrated specific binding to BCMA. GLP toxicity studies in mice showed no unexpected adverse events. We generated a retroviral construct for clinical use including a truncated epithelial growth factor receptor (EGFRt) elimination gene: EGFRt/hBCMA-41BBz. Clinical investigation of this construct is underway in a dose escalation, single institution trial. Enrollment is completed on 2/4 planned dose levels (DL). On DL1 pts received cyclophosphamide conditioning (3g/m2 x1) and 72x106 mean CAR+ T cells. On DL2 pts received lower dose cyclophosphamide/fludarabine (300/30 mg/m2 x3) and 137x106 mean CAR+ T cells. All pts screened for BCMA expression by IHC were eligible. High risk cytogenetics were present in 4/6 pts. Median prior lines of therapy was 7; all pts had IMiD, PI, high dose melphalan, and CD38 directed therapies. With a data cut off of 7/20/17, 6 pts are evaluable for safety. There were no DLT's. At DL1, grade 1 CRS, not requiring intervention, occurred in 1/3 pts. At DL2, grade 1/2 CRS occurred in 2/3 pts; both received IL6R directed Tocilizumab (Toci) with near immediate resolution. In these 2 pts time to onset of fever was a mean 2d, Tmax was 39.4-41.1 C, peak CRP was 25-27mg/dl, peak IL6 level pre and post Toci were 558-632 and 3375-9071 pg/ml, respectively. Additional serum cytokines increased >10 fold from baseline in both pts include: IFNg, GM CSF, Fractalkine, IL5, IL8, and IP10. Increases in ferritin were limited, and there were no cases of hypofibrinogenemia. There were no grade 3-5 CRS and no neurotoxicities or cerebral edema. No pts received steroids or Cetuximab. Median time to count recovery after neutropenia was 10d (range 6-15d). Objective responses by IMWG criteria after a single dose of CAR T cells were observed across both DLs. At DL1, of 3 pts, responses were 1 VGPR, 1 SD, and 1 pt treated with baseline Mspike 0.46, thus not evaluable by IMWG criteria, had >50% reduction in Mspike, and normalization of K/L ratio. At DL2, 2/2 pts had objective responses with 1 PR and 1 VGPR (baseline 95% marrow involvement); 1 pt is too early to evaluate. As we are employing a human CAR, the study was designed to allow for an optional second dose in pts that do not reach CR. We have treated 2 pts with a second dose, and longer follow up data is pending. Figure 1 Figure 1. Disclosures Smith: Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: BCMA targeted CAR T cells, Research Funding. Almo: Cue Biopharma: Other: Founder, head of SABequity holder; Institute for Protein Innovation: Consultancy; AKIN GUMP STRAUSS HAUER & FELD LLP: Consultancy. Wang: Eureka Therapeutics Inc.: Employment, Equity Ownership. Xu: Eureka Therapeutics, Inc: Employment, Equity Ownership. Park: Amgen: Consultancy. Curran: Juno Therapeutics: Research Funding; Novartis: Consultancy. Dogan: Celgene: Consultancy; Peer Review Institute: Consultancy; Roche Pharmaceuticals: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Liu: Eureka Therpeutics Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Brentjens: Juno Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding.

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Adoptive T-Cell Therapy for Acute Lymphoblastic Leukemia Targeting Multiple Tumor Associated Antigens

Blood ◽

10.1182/blood-2018-99-115465 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2693-2693

Author(s):

Swati Naik ◽

Premal Lulla ◽

Ifigeneia Tzannou ◽

Robert A. Krance ◽

George Carrum ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Disease Relapse ◽

Advisory Committees ◽

Leukemic Relapse ◽

Post Infusion ◽

Equity Ownership ◽

T Cell Lines

Abstract Background: Leukemic relapse remains the major cause of treatment failure in hematopoietic stem cell transplant (HSCT) recipients. While the infusion of donor lymphocytes to prevent and treat relapse has been clinically implemented this strategy does not provide durable remissions and carries the risk of life-threatening graft-versus-host disease (GVHD). More recently the adoptive transfer of T cells that have been engineered to express CD19-targeted chimeric antigen receptors (CARs), has shown potent anti-leukemic activity in HSCT recipients with recurrent disease. However, disease relapse with the emergence of CD19 negative tumors is an emerging clinical issue post-administration of these mono-targeted T cells. To overcome these limitations, we developed a protocol for the generation of donor-derived T cell lines that simultaneously targeted a range of tumor associated antigens (multiTAAs) that are frequently expressed by B- and T-cell ALL including PRAME, WT1 and Survivin for adoptive transfer to high risk recipients transplanted for ALL. Methods/Results: We were consistently able to generate donor-derived multiTAA-specific T cells by culturing PBMCs in the presence of a Th1-polarizing/pro-proliferative cytokine cocktail, using autologous DCs as APCs and loading them with pepmixes (15 mer peptides overlapping by 11 amino acids) spanning all 3 target antigens. The use of whole antigen increases the range of patient HLA polymorphisms that can be exploited beyond those matched to single peptides, while targeting multiple antigens simultaneously reduces the risk of tumor immune evasion. To date, we have generated 14 clinical grade multiTAA-specific T cell lines comprising CD3+ T cells (mean 94±9%) with a mixture of CD4+ (mean 21±28%) and CD8+ (mean 52±24 %) cells, which expressed central [CD45RO+/CD62L+: 14±9%] and effector memory markers [CD45RO+/CD62L-: 80±11%] associated with long term in vivo persistence. The expanded lines recognized the targeted antigens WT1, PRAME and Survivin by IFNg ELIspot with activity against >1 targeted antigens in all cases. None of the lines reacted against non-malignant patient-derived cells (4±3% specific lysis; E: T 20:1) - a study release criterion. Thus far we have treated 8 high risk ALL patients with donor derived TAA T cells post-transplant to prevent disease relapse (Table 1). Infusions were well tolerated with no dose-limiting toxicity, GVHD, CRS or other adverse events. Two patients were not evaluable per study criteria as they received >0.5mg/kg of steroids within 4 weeks of infusion and were replaced. Five of the 6 remaining patients infused remain in CR a median of 11.2 months post-infusion (range 9-22 months). We detected the expansion of tumor-reactive T cells in patient peripheral blood post-infusion against both targeted (WT1, Survivin, PRAME) and non-targeted antigens (SSX2, MAGE-A4, -A1, -A2B, -C1, MART1, AFP and NYESO1) reflecting epitope and antigen spreading. The single patient who relapsed showed no evidence of tumor-directed T cell expansion despite receiving 3 additional infusions at 4 week intervals. Conclusion: In summary, infusion of donor multi-TAA-specific T cells to patients with ALL post allogeneic HSCT is feasible, safe and as evidenced by expansion and antigen spreading in patients, may contribute to disease control. This strategy may present a promising addition to current immunotherapeutic approaches for prophylaxis for leukemic relapse in HSCT recipients. Table 1. Table 1. Disclosures Vera: Marker: Equity Ownership. Heslop:Marker: Equity Ownership; Cytosen: Membership on an entity's Board of Directors or advisory committees; Cell Medica: Research Funding; Gilead Biosciences: Membership on an entity's Board of Directors or advisory committees; Tessa Therapeutics: Research Funding; Viracyte: Equity Ownership. Leen:Marker: Equity Ownership.

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Development of Novel Second Generation DC/Tumor Fusion Vaccine in Lymphoma

Blood ◽

10.1182/blood-2019-124768 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 392-392 ◽

Cited By ~ 1

Author(s):

Shira Orr ◽

Marzia Capelletti ◽

Haider Ghiasuddin ◽

Dina Stroopinsky ◽

Jessica Liegel ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Tumor Cells ◽

Research Funding ◽

Second Generation ◽

Advisory Board ◽

Advisory Committees ◽

Equity Ownership ◽

Cells Cultured

Introduction: We have pioneered a personalized cancer vaccine in which patient derived tumor cells are fused with autologous dendritic cells (DCs) such that a broad array of shared and neo-tumor antigens is presented in the context of DC mediated co-stimulation, limiting the risk of antigen escape. In clinical trials of patients with hematologic malignancies, vaccination with DC/tumor fusions induced an expansion of tumor-specific T cells, and resulted in prolonged remissions in a subset of patients. In the current study, we have developed a novel second generation vaccine, whereby a DC/lymphoma fusion vaccine is presented in the context of a unique biomatrix that expresses high levels of the 41BB costimulatory molecule, to further accentuate T cell activation and prevent the establishment of tumor tolerance. In this study, we demonstrate efficacy of DC/lymphoma fusion cell vaccination in a preclinical lymphoma model, and show enhanced potency of the second-generation vaccine. Methods/Results: We first demonstrated the potency of the DC/tumor fusion vaccine in generating anti-tumor immunity in the A20 lymphoma model. Murine DC/A20 fusions were generated from bone marrow derived mononuclear cells cultured with GM-CSF and IL-4 then fused to syngeneic A20 lymphoma cells. DC/A20 fusion cells effectively induced tumor specific immunity as manifested by potent lysis of A20 T cells in vitro as compared to unstimulated T cells in a standard CTL assay. Consistent with this observation, vaccination with DC/A20 fusions effectively induced lymphoma specific immunity in an immunocompetent murine model. Balb/C mice (30 animals) underwent IV inoculation with 750,000 syngeneic, luciferase and mCherry transduced, A20 cells. 24 hours after tumor cells challenge, 15 mice were treated subcutaneously with 105 DC/A20 fusions. Tumor burden was detected using BLI imaging. 10 days post inoculation, within the untreated cohort all 15/15 mice had detectable tumor whereas within the treated group, 5 mice did not demonstrate any evidence of disease and 5 mice demonstrated minimal disease. We subsequently demonstrated that patient derived autologous DC/lymphoma fusions stimulated T cell mediated lysis of primary lymphoma cells. DC were generated from patient derived peripheral blood mononuclear cells cultured with GM-CSF and IL-4 and matured with TNFa. Primary lymphoma cells were isolated from resected tumor and fused with DC at a ratio of 10:1. Fusion stimulated T cells potently lysed autologous tumor cells as compared to unstimulated T cells (25.7% as compared to 12.66%) in a standard CTL assay. To further enhance vaccine potency, we developed a biomatrix substrate expressing the costimulatory molecule 41BB. Using carbodiimide chemistry we covalently bonded RGD peptide and 41BBL protein to an alginate (Alg)-based scaffold. The Alg/RGD/41BBL scaffold can serve as a supporting microenvironment for the co-culture of T cells and fusion vaccine. We cultured syngeneic T cells with DC/A20 fusion vaccine within a scaffold with or without bound 41BBL and examined the T cells cytotoxicity by a CTL assay as described above. Vaccine mediated stimulation of T cells in the context of the Alg/RGD/41BBL scaffold demonstrated higher levels of tumor lysis as compared to the percent T cells cultured within an Alg/RGD scaffold (22.95% and 13.95% respectively). Conclusion: In the current study we assessed the efficacy of the DC/Lymphoma fusion vaccine to elicit a tumor specific immune response. We succeeded in demonstrating the capacity of DC/Lymphoma fusion vaccine to generate tumor specific T cell cytotoxicity in vitro as well as in vivo in an immunocompetent murine model. Accordingly, we presented patient derived primary tumor results supporting the applicable nature of the DC/Lymphoma vaccine in lymphoma patients. In addition, we developed a second-generation fusion vaccine comprised of the original DC/Tumor vaccine presented to the T cells in an Alg/RGD/41BBL scaffold acting as a nurturing microenvironment for T cell immune specific response against the tumor cells. Our initial results exhibit promising potential and an in vivo experiment with the second-generation fusion vaccine is ongoing. Disclosures Arnason: Celgene/Juno: Consultancy; Regeneron Pharmaceuticals, Inc.: Consultancy. Kufe:Nanogen Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Genus Oncology: Equity Ownership; Reata Pharmaceuticals: Consultancy, Equity Ownership, Honoraria; Hillstream BioPharma: Equity Ownership; Victa BioTherapeutics: Consultancy, Equity Ownership, Honoraria, Membership on an entity's Board of Directors or advisory committees; Canbas: Consultancy, Honoraria. Rosenblatt:Dava Oncology: Other: Education; BMS: Research Funding; Partner Tx: Other: Advisory Board; Merck: Other: Advisory Board; Parexel: Consultancy; Imaging Endpoint: Consultancy; Celgene: Research Funding; BMS: Other: Advisory Board ; Amgen: Other: Advisory Board. Avigan:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Partners Tx: Membership on an entity's Board of Directors or advisory committees; Partner Tx: Membership on an entity's Board of Directors or advisory committees; Karyopharm: 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; Janssen: Consultancy; Parexel: Consultancy; Takeda: Consultancy.

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Phase 2 Study of the Response and Safety of P-Bcma-101 CAR-T Cells in Patients with Relapsed/Refractory (r/r) Multiple Myeloma (MM) (PRIME)

Blood ◽

10.1182/blood-2019-129562 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3184-3184 ◽

Cited By ~ 16

Author(s):

Caitlin L. Costello ◽

Tara K. Gregory ◽

Syed Abbas Ali ◽

Jesus G. Berdeja ◽

Krina K. Patel ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Phase 2 ◽

Employment Equity ◽

Advisory Committees ◽

Car T Cells ◽

Car T ◽

Equity Ownership

P-BCMA-101 is a novel chimeric antigen receptor (CAR)-T cell product targeting B Cell Maturation Antigen (BCMA). P-BCMA-101 is produced using the piggyBac® (PB) DNA Modification System instead of the viral vector that is used with most CAR-T cells, requiring only plasmid DNA and mRNA. This makes it less costly and produces cells with a high percentage of the favorable T stem cell memory phenotype (TSCM). The higher cargo capacity of PB permits the incorporation of multiple genes in addition to CAR(s), including a safety switch allowing for rapid CAR-T cell elimination with a small molecule drug infusion in patients if desired, and a selection gene allowing for enrichment of CAR+ cells. Rather than using a traditional antibody-based binder, P-BCMA-101 has a Centyrin™ fused to a CD3ζ/4-1BB signaling domain. Centyrins are fully human proteins with high specificity and a large range of binding affinities, but are smaller, more stable and potentially less immunogenic than traditional scFv. Cumulatively, these features are predicted to result in a greater therapeutic index. A Phase 1, 3+3 dose escalation from 0.75 to 15 x 106 P-BCMA-101 CAR-T cells/kg (RP2D 6-15 x 106 cells/kg) was conducted in patients with r/r MM (Blood 2018 132:1012) demonstrating excellent efficacy and safety of P-BCMA-101, including notably low rates and grades of CRS and neurotoxicity (maximum Grade 2 without necessitating ICU admission, safety switch activation or other aggressive measures). These results supported FDA RMAT designation and initiation of a pivotal Phase 2 study. A Phase 2 pivotal portion of this study has recently been designed and initiated (PRIME; NCT03288493) in r/r MM patients who have received at least 3 prior lines of therapy. Their therapy must have contained a proteasome inhibitor, an IMiD, and CD38 targeted therapy with at least 2 of the prior lines in the form of triplet combinations. They must also have undergone ≥2 cycles of each line unless PD was the best response, refractory to the most recent line of therapy, and undergone autologous stem cell transplant or not be a candidate. Patients are required to be >=18 years old, have measurable disease by International Myeloma Working Group criteria (IMWG; Kumar 2016), adequate vital organ function and lack significant autoimmune, CNS and infectious diseases. No pre-specified level of BCMA expression is required, as this has not been demonstrated to correlate with clinical outcomes for P-BCMA-101 and other BCMA-targeted CAR-T products. Interestingly, unlike most CAR-T products patients may receive P-BCMA-101 after prior CAR-T cells or BCMA targeted agents, and may be multiply infused with P-BCMA-101. Patients are apheresed to harvest T cells, P-BCMA-101 is then manufactured and administered to patients as a single intravenous (IV) dose (6-15 x 106 P-BCMA-101 CAR-T cells/kg) after a standard 3-day cyclophosphamide (300 mg/m2/day) / fludarabine (30 mg/m2/day) conditioning regimen. One hundred patients are planned to be treated with P-BCMA-101. Uniquely, given the safety profile demonstrated during Phase 1, no hospital admission is required and patients may be administered P-BCMA-101 in an outpatient setting. The primary endpoints are safety and response rate by IMWG criteria. With a 100-subject sample, the Phase 2 part of the trial will have 90% power to detect a 15-percentage point improvement over a 30% response rate (based on that of the recently approved anti-CD38 antibody daratumumab), using an exact test for a binomial proportion with a 1-sided 0.05 significance level. Multiple biomarkers are being assessed including BCMA and cytokine levels, CAR-T cell kinetics, immunogenicity, T cell receptor diversity, CAR-T cell and patient gene expression (e.g. Nanostring) and others. Overall, the PRIME study is the first pivotal study of the unique P-BCMA-101 CAR-T product, and utilizes a number of novel design features. Studies are being initiated in combination with approved therapeutics and earlier lines of therapy with the intent of conducting Phase 3 trials. Funding by Poseida Therapeutics and the California Institute for Regenerative Medicine (CIRM). Disclosures Costello: Takeda: Honoraria, Research Funding; Janssen: Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Gregory:Poseida: Research Funding; Celgene: Speakers Bureau; Takeda: Speakers Bureau; Amgen: Speakers Bureau. Ali:Celgene: Research Funding; Poseida: Research Funding. Berdeja:Amgen Inc, BioClinica, Celgene Corporation, CRISPR Therapeutics, Bristol-Myers Squibb Company, Janssen Biotech Inc, Karyopharm Therapeutics, Kite Pharma Inc, Prothena, Servier, Takeda Oncology: Consultancy; AbbVie Inc, Amgen Inc, Acetylon Pharmaceuticals Inc, Bluebird Bio, Bristol-Myers Squibb Company, Celgene Corporation, Constellation Pharma, Curis Inc, Genentech, Glenmark Pharmaceuticals, Janssen Biotech Inc, Kesios Therapeutics, Lilly, Novartis, Poseida: Research Funding; Poseida: Research Funding. Patel:Oncopeptides, Nektar, Precision Biosciences, BMS: Consultancy; Takeda, Celgene, Janssen: Consultancy, Research Funding; Poseida Therapeutics, Cellectis, Abbvie: Research Funding. Shah:University of California, San Francisco: Employment; Genentech, Seattle Genetics, Oncopeptides, Karoypharm, Surface Oncology, Precision biosciences GSK, Nektar, Amgen, Indapta Therapeutics, Sanofi: Membership on an entity's Board of Directors or advisory committees; Indapta Therapeutics: Equity Ownership; Celgene, Janssen, Bluebird Bio, Sutro Biopharma: Research Funding; Poseida: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Nkarta: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite: Consultancy, Membership on an entity's Board of Directors or advisory committees; Teneobio: Consultancy, Membership on an entity's Board of Directors or advisory committees. Ostertag:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Martin:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Ghoddusi:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Shedlock:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Spear:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Orlowski:Poseida Therapeutics, Inc.: Research Funding. Cohen:Poseida Therapeutics, Inc.: Research Funding.

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Influence of Karyotype On Overall Survival in Patients with Higher-Risk Myelodysplastic Syndrome Treated with Azacitidine or a Conventional Care Regimen.

Blood ◽

10.1182/blood.v114.22.1755.1755 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1755-1755 ◽

Cited By ~ 5

Author(s):

Ghulam J Mufti ◽

Steven D. Gore ◽

Valeria Santini ◽

Pierre Fenaux ◽

Lewis R. Silverman ◽

...

Keyword(s):

Overall Survival ◽

Board Of Directors ◽

Research Funding ◽

Conventional Care ◽

Complex Karyotype ◽

Trisomy 8 ◽

Employment Equity ◽

Advisory Committees ◽

Cytogenetic Abnormalities ◽

Equity Ownership

Abstract Abstract 1755 Poster Board I-781 Background Karyotypic abnormalities are common in myelodysplastic syndromes (MDS), and specific chromosomal abnormalities are associated with poor prognosis. The phase III AZA-001 study (Lancet Oncol, 2009) showed azacitidine (AZA) prolonged overall survival (OS) regardless of IPSS cytogenetic risk category. This analysis assessed the effects of specific cytogenetic abnormalities on OS in patient (pt) subgroups treated with AZA or a conventional care regimen (CCR). Methods Pts with higher-risk MDS (FAB RAEB, RAEB-t, or CMML and IPSS Int-2 or High) were enrolled and randomized to receive AZA or CCR. CCR comprised 3 treatments: best supportive care only, low-dose ara-C, or induction chemotherapy. Erythropoietins were prohibited. OS was determined in subgroups of pts with del 5/5q-, del 7/7q-, or trisomy 8, each as part of a non-complex karyotype (<3 cytogenetic abnormalities) or as part of a complex karyotype (≥3 cytogenetic abnormalities). OS was also analyzed in pts with combinations of del 5/5q- and/or del 7/7q- as part of non-complex or complex karyotypes (Table). Pt karyotype was determined at baseline. OS was assessed using Kaplan-Meier methods. A stratified Cox proportional hazards regression model was used to estimate hazard ratios (HRs) and associated 95% confidence intervals (CI). Results A total of 358 pts were enrolled (AZA 179, CCR 179). Of them, 153 had normal karyotypes (AZA 77, CCR 76). Median OS in pts with normal karyotypes was not reached at 21.1 months with AZA vs 17.2 months (95%CI: 15.2 – 24.1 months) with CCR; HR = 0.63 (95%CI: 0.39 – 1.03). Of remaining pts, 136 had del 5/5q-, del 7/7q-, and/or trisomy 8 as part of a non-complex or complex karyotype. AZA was associated with longer OS vs CCR in all subgroups of pts with non-complex cytogenetics, with HRs ranging from 0.20 (95%CI: 0.06 – 0.65) to 0.51 (95%CI: 0.05 – 4.74) (Table). In both the AZA and CCR treatment groups, pts in all subgroups with non-complex karyotypes had substantially longer OS than pts with complex karyotypes. Pts with complex karyotypes in some subgroups had longer OS with AZA vs CCR: median OS in pts with del 5/5q-, del 5/5q- WITHOUT del 7/7q-, or trisomy 8 as part of a complex karyotype treated with AZA survived 5.1, 8.0, and 12.4 months longer, respectively, than their counterparts who received CCR. HRs with AZA vs CCR in pts with complex cytogenetics ranged from 0.42 (95%CI: 0.10 – 1.69) to 0.55 (95%CI: 0.29 – 1.05). Conclusions These findings support earlier data showing effectiveness of AZA in higher-risk MDS pts with complex or non-complex karyotypes. Major gains in OS were obtained with AZA vs CCR (12-18 months longer OS with AZA) for the following categories: del 7/7q- (non-complex), del 7/7q- WITHOUT del 5/5q- (non-complex), and trisomy 8 (non-complex and complex). Pts with trisomy 8 treated with AZA experienced a 3-fold increase in median OS compared with similar pts who received CCR. Longer OS (AZA 15.3 vs CCR 7.3 months) was also obtained for pts with del5/5q- WITHOUT del7/7q- as part of a complex karyotype. The worse cytogenetic categories, del 7/7q- and del 5/5q- AND del 7/7q-, both with complex karyotype, were associated with the poorest OS regardless of treatment. Pt subgroups in this post hoc analysis were small and heterogeneous; confirmation of these findings in larger pt samples is warranted. Disclosures Mufti: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Gore:Celgene: Consultancy, Equity Ownership, Research Funding; Johnson & Johnson: Research Funding. Santini:Celgene: Honoraria. Fenaux:Celgene: Honoraria, Research Funding; Ortho Biotech: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Cephalon: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; MSD: Honoraria, Research Funding; Epicept: Honoraria, Research Funding. Skikne:Celgene: Employment, Equity Ownership. Hellstrom-Lindberg:Celgene: Research Funding. Seymour:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Beach:Celgene: Employment, Equity Ownership. Backstrom:Celgene: Employment, Equity Ownership. Fernando:Celgene: Employment, Equity Ownership.

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Aberrant a-to-I RNA Editing and Prognostic Impact of Adar in Multiple Myeloma Patients with 1q Amplification

Blood ◽

10.1182/blood.v128.22.357.357 ◽

2016 ◽

Vol 128 (22) ◽

pp. 357-357

Author(s):

Alessandro Lagana ◽

Deepak Perumal ◽

Violetta V Leshchenko ◽

Pei-Yu Kuo ◽

Brian Kidd ◽

...

Keyword(s):

Overall Survival ◽

Board Of Directors ◽

Rna Editing ◽

Copy Number ◽

Research Funding ◽

Cox Regression ◽

Advisory Committees ◽

Cox Regression Analysis ◽

Kaplan Meier ◽

Equity Ownership

Abstract Amplification of 1q is observed in 40% of Multiple Myeloma (MM) patients and is associated with a more aggressive clinical course of the disease. The frequency of 1q21 amplifications has been shown to increase significantly in the transition from monoclonal gammopathy of undetermined significance (MGUS) to overt myeloma and to relapse. Previous studies have reported genes on 1q such as ANP32E and CSK1B that have significant impact on survival. However, the biological mechanisms underlying disease aggressiveness associated to 1q amplification still remain unclear. ADAR (Adenosine Deaminase Acting on RNA) is an enzyme responsible for A-to-I editing, a post-transcriptional modification of double stranded RNA consisting in the conversion of specific Adenosines (A) into Inosines (I) by deamination. As Inosine is structurally similar to Guanosine (G), editing events can result in functional consequences in RNA and protein structure, including non-synonymous changes in protein coding sequences and creation/disruption of miRNA binding sites on UTRs. Dysregulation of A-to-I editing by ADAR has been recently linked to cancer. Since the ADAR gene is located in 1q21.3 (the critical minimally amplified region in MM), we asked whether 1q amplification affected ADAR expression, RNA editing and overall prognosis in MM patients. We identified 44 patients with 1q amplification from the IA6 release of the MMRF CoMMpass dataset. As a control group (wt), we selected an equal number of patients from CoMMpass without any 1q alteration. Gene expression analysis showed significantly higher expression of ADAR in 1q-amp patients compared to wt (q = 3.64e-7) (Fig. 1) and significant correlation between ADAR copy number and its expression (Spearman ρ=0.69, p = 4.52e-14). To evaluate the functional impact of ADAR up-regulation, we applied a computational pipeline based on the tool REDItools and our in-house scripts to detect A-to-I edited sites in RNA-Seq samples. The pipeline identified candidate A-to-G mutations in RNA sequences using corresponding Whole-Exome Sequencing data to filter out actual DNA mutations. We calculated sample-wise mean editing frequency across all edited sites and found significantly increased editing in 1q-amp patients compared to wt (p = 4.3e-5) (Fig. 2). Mean editing frequency was significantly correlated with ADAR expression (ρ = 0.62, p < 2e-16) and ADAR copy number (ρ= 0.5, p= 4.32e-7). Our analysis identified 3,286 sites residing in Alu sequences and 1,303 in non-Alu regions. A-to-I editing has been shown to occur predominantly in Alu elements, repetitive sequences abundantly interspersed throughout the human genome, mostly within introns and untranslated regions (UTRs). As expected, most sites were reported within 3' UTRs (66%) and introns (12%). Overall, at the site level, we observed increased editing in 1q-amp vs wt (p < 2e-16). We found that 2,173 sites (47%) had significant differential editing frequency between 1q-amp and wt patients (FDR < 20%). Next, we sought to assess the prognostic implications of ADAR activity. Cox regression analysis revealed a trend toward higher risk in terms of EFS (Event Free Survival) for 1q-amp vs wt (HR = 1.7, 95% CI = 0.83-3.59, p = 0.13), as well as for patients with higher expression of ADAR (HR = 2.4, 95% CI = 0.79-7.15, p = 0.11) and higher mean editing frequency (HR = 2, 95% CI = 0.72-5.59, p = 0.17). Since survival data in the CoMMpass dataset is not yet mature, we evaluated the effects of ADAR expression on survival on an independent dataset consisting of 559 samples from newly diagnosed patients pre-TT2 and -TT3 treatments (GSE2658, Shaughnessy et al, Blood 2007; 109:2276-84). Cox regression analysis showed a significant difference in terms of overall survival between patients with low and high ADAR expression, the latter being correlated with higher risk (HR = 2, 95% CI = 1.18-3.66, p = 0.01) (Fig. 3). In conclusion, we found a significant increase in ADAR expression and aberrant A-to-I RNA editing in MM patients with amplification of 1q. These results demonstrate a novel mechanism by which 1q amplification can contribute to MM pathogenesis via induction of A-to-I RNA editing by ADAR. Figure 1 ADAR expression in 1q-amp vs wt patients. Figure 1. ADAR expression in 1q-amp vs wt patients. Figure 2 Difference in mean RNA editing frequency between 1q-amp and wt patients. Figure 2. Difference in mean RNA editing frequency between 1q-amp and wt patients. Figure 3 Kaplan-Meier curves of overall survival in the Shaughnessy cohort stratified by ADAR expression (GSE2658) Figure 3. Kaplan-Meier curves of overall survival in the Shaughnessy cohort stratified by ADAR expression (GSE2658) Disclosures Chari: Janssen: Consultancy, Research Funding; Pharmacyclics: Research Funding; Takeda: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Amgen Inc.: Honoraria, Research Funding; Array Biopharma: Consultancy, Research Funding; Novartis: Consultancy, Research Funding. Cho:Ludwig Institute for Cancer Research: Membership on an entity's Board of Directors or advisory committees; Agenus, Inc.: Research Funding; Genentech Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding. Barlogie:Signal Genetics: Patents & Royalties. Jagannath:Janssen: Consultancy; Celgene: Consultancy; Merck: Consultancy; Bristol-Myers Squibb: Consultancy; Novartis: Consultancy. Dudley:NuMedii, Inc.: Patents & Royalties; AstraZeneca: Speakers Bureau; Ontomics, Inc.: Equity Ownership; NuMedii, Inc.: Equity Ownership; Ecoeos, Inc.: Equity Ownership; Ayasdi, Inc.: Equity Ownership; Janssen Pharmaceuticals, Inc.: Consultancy; GlaxoSmithKline: Consultancy; Personalis: Patents & Royalties.

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CD20-TCB, a Novel T-Cell-Engaging Bispecific Antibody, Induces T-Cell-Mediated Killing in Relapsed or Refractory Non-Hodgkin Lymphoma: Biomarker Results From a Phase I Dose-Escalation Trial

Blood ◽

10.1182/blood-2019-123979 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 5319-5319 ◽

Cited By ~ 2

Author(s):

Ann-Marie E Bröske ◽

Ian James ◽

Anton Belousov ◽

Enrique Gomez ◽

Marta Canamero ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

Board Of Directors ◽

T Cell Activation ◽

Research Funding ◽

Cell Activation ◽

Employment Equity ◽

Advisory Committees ◽

Equity Ownership

Introduction: CD20-TCB (RG6026) is a novel T-cell-engaging bispecific (TCB) antibody with a '2:1' molecular format that comprises two fragment antigen binding regions that bind CD20 (on the surface of B cells) and one that binds CD3 (on the surface of T cells). CD20-TCB offers the potential for increased tumor antigen avidity, rapid T-cell activation, and enhanced tumor cell killing versus other bispecific formats. The safety, tolerability, pharmacokinetics, biomarkers, and antitumor activity of CD20-TCB are currently being investigated in a multicenter Phase I dose-escalation trial (NP30179; NCT03075696). We recently presented preliminary clinical data demonstrating promising clinical activity in relapsed or refractory (R/R) non-Hodgkin lymphoma (NHL) patients with indolent or aggressive disease (Dickinson et al. ICML 2019). Here, we present preliminary blood and tissue biomarker analyses to explore modes of action, support optimal biological dose selection, and identify potential outcome predictors. Methods: For biomarker analyses, we performed immune profiling of peripheral blood by flow cytometry, analyzed plasma cytokine levels by ELISA, and characterized baseline and on-treatment tumor biopsies by immunohistochemistry/immunofluorescence assays and RNA sequencing. Biomarker data were obtained from 122 patients dosed with 0.005-25mg CD20-TCB. Results: CD20-TCB infusion led to a rapid and transient reduction in T cells in the peripheral circulation (T-cell margination) in all patients. T-cell margination reached nadir 6 hours after the first CD20-TCB infusion, and showed a strong association with CD20-TCB dose and receptor occupancy (RO%; as determined by Djebli et al. ASH 2019). Interestingly, rebound of T cells 160 hours after the first CD20-TCB infusion was associated with response to treatment. Responding patients showed long-term T-cell activation after the first infusion of CD20-TCB at doses from 0.6mg and above. T-cell activation was demonstrated by 2-4-fold elevation of T-cell activation markers such as Ki67, HLA-DR, PD-1, ICOS, OX40, and 4-1BB, which was sustained up to Cycle 5 (105 days). Analysis of paired pre- and on-treatment tumor biopsies (n=6) obtained before and 2-3 weeks after the first dose of CD20-TCB showed evidence of T-cell-mediated tumor cell killing. Analysis of archival and pre-treatment tumor biopsies (n=80) revealed that clinical responses were achieved irrespective of the amount of tumor T-cell infiltration at baseline. In contrast, preliminary baseline bulk tumor RNA sequencing data (n=46) showed upregulation of gene signatures associated with cell proliferation/Myc and T-cell subsets (effector vs exhausted-like) in non-responding patients. Conclusions: In this study, we demonstrated the mode of action of CD20-TCB, a novel bispecific antibody with promising clinical activity in R/R NHL. We also demonstrated that biomarker data on T-cell activation can support dose finding in conjunction with pharmacokinetics. Additional analysis is ongoing to evaluate response predictors and better characterize the population that will benefit most from T-cell mediated therapies. Disclosures Bröske: Roche: Employment, Equity Ownership. James:A4P Consulting Ltd: Consultancy. Belousov:Roche: Employment. Gomez:F. Hoffmann-La Roche Ltd: Employment. Canamero:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Ooi:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Grabole:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Wilson:F. Hoffmann-La Roche Ltd: Employment. Korfi:F. Hoffmann-La Roche Ltd: Consultancy. Kratochwil:F. Hoffmann-La Roche Ltd: Employment. Morcos:Roche: Employment, Equity Ownership. Ferlini:Roche: Employment, Equity Ownership. Thomas:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Dimier:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Moore:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Bacac:Roche: Employment, Equity Ownership, Patents & Royalties: Patents, including the one on CD20-TCB. Weisser:Pharma Research and Early Development Roche Innovation Center Munich: Employment, Equity Ownership, Patents & Royalties. Dickinson:Merck Sharpe and Dohme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; GlaxoSmithKline: 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, Speakers Bureau. OffLabel Disclosure: CD20-TCB (also known as RG6026, RO7082859) is a full-length, fully humanized, immunoglobulin G1 (IgG1), T-cell-engaging bispecific antibody with two fragment antigen binding (Fab) regions that bind to CD20 (on the surface of B cells) and one that binds to CD3 (on the surface of T cells) (2:1 format). The 2:1 molecular format of CD20-TCB, which incorporates bivalent binding to CD20 on B cells and monovalent binding to CD3 on T cells, redirects endogenous non-specific T cells to engage and eliminate malignant B cells. CD20-TCB is an investigational agent.

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T Cells Educated By DC/AML Fusions in the Context of 4-1BB Costimulation As a Potent Strategy for Adoptive Cellular Therapy

Blood ◽

10.1182/blood-2019-131491 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2673-2673

Author(s):

Jessica Liegel ◽

Dina Stroopinsky ◽

Haider Ghiasuddin ◽

Adam Morin ◽

Marzia Capelletti ◽

...

Keyword(s):

T Cells ◽

Board Of Directors ◽

Research Funding ◽

Cellular Therapy ◽

Ex Vivo ◽

Advisory Board ◽

Adoptive Cellular Therapy ◽

Advisory Committees ◽

Equity Ownership

Introduction: Our group has developed a novel vaccine using patient-derived acute myeloid leukemia (AML) cells and autologous dendritic cells (DCs), capable of presenting a broad array of leukemia antigens. In a phase I/II clinical trial DC/AML vaccination led to an expansion of leukemia-specific T cells. We hypothesized that the fusion vaccine offered a unique platform for ex vivo expansion of functionally potent leukemia specific T cells with broad specificity targeting shared and tumor specific neoantigens. We postulated that incorporating 4-1BB (CD137) mediated co-stimulation would further enhance activation of antigen specific T cells and the development of a crucial memory response as well as promote survival and persistence. Here we describe therapeutic exploration of the use of 4-1BB to augment vaccine-educated T cells for adoptive cellular therapy in an immunocompetent murine model. Methods: DC/AML fusion vaccine was generated using DCs obtained from C57BL/6J mice and syngeneic C1498 AML cells as previously described. T cells were obtained from splenocytes after magnetic bead isolation and cultured with irradiated DC/AML fusion vaccine in the presence of IL-15 and IL-7. Following co-culture, 4-1BB positive T cells were ligated using agonistic 4-1BB antibody (3H3 clone, BioXCell) and further selected with RatIgG2a magnetic beads (Easy Sep). Subsequently T cells were expanded with anti-CD3/CD28 activation beads (Dynabeads). In vivo, mice underwent retro-orbital inoculation with C1498 and vaccination with irradiated fusion cells the following day. Agonistic mouse anti-4-1BB antibody was injected intraperitoneally on day 4 and day 7. In addition, C1498 cells were transduced with Mcherry/luciferase and a reproducible model of disease progression was established. Results: DC/fusion stimulated T cells showed increased immune activation as measured by multichannel flow cytometric analysis. Compared to unstimulated T cells, there was 5-fold increase in CD4+CD25+CD69+, and a 10-fold and 7-fold increase in 4-1BB and intracellular IFNƔ expression on CD8+ cells respectively. Following agonistic 4-1BB ligation and bead isolation, the proliferation rate was increased in the 4-1BB positive fraction as compared to both 4-1BB negative cells and unstimulated T cells. In addition, the 4-1BB positive fraction demonstrated increased cytotoxicity, as measured by a CTL assay detecting granzyme B with 1:10 tumor to effector cells. A shift from naïve to memory T cell phenotype was also observed. Following DC/fusion stimulation, CD44+CD62L- cells comprised 67% of CD8+ cells versus 20% without stimulation, the latter reflecting the effect of cytokines alone. Following 4-1BB ligation and anti-CD3/CD28 bead expansion, this phenotype was retained with the CD4+ and CD8+ effector memory and central memory compartments comprising the majority of T cells. Such findings are significant as presence of memory T cell populations are a critical component for successful adoptive cell transfer. The effect of agonistic 4-1BB antibody following vaccination was evaluated in vivo in an aggressive immunocompetent murine AML model. The combination of DC/AML fusion vaccine with 4-1BB antibody was associated with increased long-term survival (>120 days) of 40% versus 20% of mice treated with vaccine alone while all controls required euthanasia by 40 days. Conclusion: In the current study we have demonstrated the ability of DC/AML fusion vaccine to stimulate T cells ex-vivo as demonstrated by both early-activation (CD25,CD69), upregulation of antigen-specific markers (CD137) and cytokine secretion. Further enhancement of the cellular product using agonistic 4-1BB ligation and isolation simultaneously enriches for antigen-activated cells, as demonstrated by more potent cytotoxicity, as well as promoting memory phenotype and survival. Use of 4-1BB ligation for antigen-specific selection while providing an agonistic co-stimulatory signal is a potentially novel approach for development of non-engineered T cells. Ongoing experiments evaluating the efficacy of 4-1BB selected vaccine educated T cells using bioluminescence monitoring will be reported as well as in vitro use of patient-derived T cells. Disclosures Kufe: Canbas: Consultancy, Honoraria; Victa BioTherapeutics: Consultancy, Equity Ownership, Honoraria, Membership on an entity's Board of Directors or advisory committees; Genus Oncology: Equity Ownership; Hillstream BioPharma: Equity Ownership; Reata Pharmaceuticals: Consultancy, Equity Ownership, Honoraria; Nanogen Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Rosenblatt:Dava Oncology: Other: Education; Partner Tx: Other: Advisory Board; Parexel: Consultancy; Celgene: Research Funding; BMS: Research Funding; Amgen: Other: Advisory Board; Merck: Other: Advisory Board; BMS: Other: Advisory Board ; Imaging Endpoint: Consultancy. Avigan:Takeda: Consultancy; Parexel: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Partners Tx: Membership on an entity's Board of Directors or advisory committees; Partner Tx: Membership on an entity's Board of Directors or advisory committees; Karyopharm: 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; Janssen: Consultancy.

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