scholarly journals Phase 1 First-in-Human Trial of AMV564, a Bivalent Bispecific (2x2) CD33/CD3 T-Cell Engager, in Patients with Relapsed/Refractory Acute Myeloid Leukemia (AML)

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1455-1455 ◽  
Author(s):  
Peter Westervelt ◽  
Gail J. Roboz ◽  
Jorge E. Cortes ◽  
Hagop M. Kantarjian ◽  
Sangmin Lee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Dose Level ◽  
T Cell Activation ◽  
Research Funding ◽  
Cell Activation ◽  
Phase 1 ◽  
Disease Stage ◽  
Molecular Abnormalities ◽  
Grade 3

Abstract Background: AMV564 is a novel bivalent, bispecific (2x2) CD33/CD3 targeted immunotherapy that binds both CD33 and the invariant CD3ε on T-cell receptors with strong avidity, thus creating an immune synapse between CD33-expressing cells and T cells, initiating T-cell directed lysis of CD33 expressing cells, and inducing expansion, differentiation and proliferation of T cells. By design, AMV564 has reduced clearance and therefore has a longer half-life (t1/2) than monovalent, bispecific T-cell engagers. In preclinical investigations using both leukemic cell lines and primary cells from AML patients, AMV564 eliminated myeloid blasts with picomolar potency and broad activity independent of cytogenetic or molecular abnormalities, CD33 expression level, and disease stage, with no nonspecific activation of T cells (Reusch U et al. Clin Cancer Res 2016;22:5829-38). Methods: This is an ongoing Phase 1 study with a 3+3 dose-escalation design (NCT03144245). The primary objectives of this study are to characterize the safety, tolerability, and preliminary anti-leukemic activity of AMV564. Evaluation of pharmacokinetics (PK), cytokine changes, and immunophenotyping are secondary objectives. Key inclusion/exclusion criteria are: adults with relapsed and/or refractory AML after 1-2 prior induction regimens (with a standard anthracycline-based regimen or hypomethylating agent) and no more than 2 prior salvage regimens. AMV564 is administered by continuous intravenous infusion (CIV) for 14 consecutive days for up to 2 induction cycles. AMV564 and cytokine (IL2, IL4, IL6, IL8, IL10, TNF-α, and IFN-γ) concentrations were measured by validated immunoassays. T-cell activation was measured using flow cytometry to quantify T cells expressing CD25, CD38, CD69, or HLA-DR. Results: To date, 19 patients (10 male/9 female) with a median age of 72 years (range 24-84) have been enrolled in 6 dosing cohorts: 0.5, 1.5, 5.0, 15, 50, and 100 mcg/day. Thirteen patients (68%) had secondary AML and/or adverse cytogenetics, including 6 patients (32%) with a p53 mutation. Fifteen patients (79%) had received at least 1 prior salvage regimen and 11 (58%) had received prior intensive chemotherapy, including 6 patients (32%) who had received a high-dose (≥ 1 gm/m2) cytarabine-based regimen. Overall, 18 patients were evaluable for toxicity and response. No dose-limiting toxicity or treatment-related grade ≥ 3 adverse events (AE) were reported. Grade 2 CRS was observed in 1 patient (treated at 50 mcg/day) without a lead-in dose and was managed with drug interruption and 1 dose of tocilizumab. The patient was able to resume dosing and completed the full 14-day scheduled therapy without recurrence of CRS. Subsequent patients treated at 50 mcg/day and above were given a 15 mcg/day lead-in dose for 3 days followed by 11 days at the assigned dose level. The most common grade ≥ 3 treatment-emergent AE has been febrile neutropenia, reported in 39% (7/18) of patients and all considered unrelated to study drug. No patient has died within 30 days of treatment initiation. AMV564 PK was linear with a terminal t1/2 of 2-3 days. Plasma concentrations increased gradually, with times to steady-state concentration of 3-7 days. Marked increases in IL6 (peak concentration, 1.1 ng/mL), IL8 (1.5 ng/mL), and IL10 (0.3 ng/mL) cytokines were observed and increased numbers of activated T-cells were detected post-treatment. Reductions in bone marrow blasts, ranging from 13% to 91%, were observed in 12 of 18 evaluable patients including a partial response after cycle 1 in 1 patient at the 100 mcg/day dose level. Conclusions: AMV564 is well-tolerated and demonstrates anti-leukemic activity through T-cell engagement. AMV564 has a unique PK profile with a gradual increase in drug concentration and thus the potential for controlled T-cell activation. Disclosures Roboz: Daiichi Sankyo: Consultancy; Argenx: Consultancy; Sandoz: Consultancy; Aphivena Therapeutics: Consultancy; Cellectis: Research Funding; Argenx: Consultancy; Eisai: Consultancy; Celgene Corporation: Consultancy; Roche/Genentech: Consultancy; Jazz Pharmaceuticals: Consultancy; Otsuka: Consultancy; Roche/Genentech: Consultancy; Jazz Pharmaceuticals: Consultancy; Otsuka: Consultancy; AbbVie: Consultancy; Astex Pharmaceuticals: Consultancy; Celgene Corporation: Consultancy; Janssen Pharmaceuticals: Consultancy; AbbVie: Consultancy; Astex Pharmaceuticals: Consultancy; Bayer: Consultancy; Novartis: Consultancy; Sandoz: Consultancy; Novartis: Consultancy; Celltrion: Consultancy; Aphivena Therapeutics: Consultancy; Pfizer: Consultancy; Cellectis: Research Funding; Eisai: Consultancy; Orsenix: Consultancy; Celltrion: Consultancy; Bayer: Consultancy; Pfizer: Consultancy; Janssen Pharmaceuticals: Consultancy; Daiichi Sankyo: Consultancy; Orsenix: Consultancy. Cortes:Novartis: Consultancy, Research Funding; Astellas Pharma: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Arog: Research Funding. Lee:AstraZeneca: Consultancy; Clinipace: Consultancy; Karyopharm Therapeutics Inc: Consultancy; LAM Therapeutics: Research Funding; Amgen: Consultancy. Rettig:Amphivena Therapeutics: Research Funding; Novimmune: Research Funding. Han:Amphivena Therapeutics, Inc: Employment. Guenot:Amphivena Therapeutics, Inc: Employment. Feldman:Amphivena Therapeutics, Inc: Employment.

scholarly journals A T-cell–redirecting bispecific G-protein–coupled receptor class 5 member D x CD3 antibody to treat multiple myeloma

Blood ◽  
2020 ◽  
Vol 135 (15) ◽  
pp. 1232-1243 ◽  
Author(s):  
Kodandaram Pillarisetti ◽  
Suzanne Edavettal ◽  
Mark Mendonça ◽  
Yingzhe Li ◽  
Mark Tornetta ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
G Protein ◽  
T Cell Activation ◽  
Cell Activation ◽  
Plasma Cells ◽  
Phase 1 ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled

Abstract T-cell–mediated approaches have shown promise in myeloma treatment. However, there are currently a limited number of specific myeloma antigens that can be targeted, and multiple myeloma (MM) remains an incurable disease. G-protein–coupled receptor class 5 member D (GPRC5D) is expressed in MM and smoldering MM patient plasma cells. Here, we demonstrate that GPRC5D protein is present on the surface of MM cells and describe JNJ-64407564, a GPRC5DxCD3 bispecific antibody that recruits CD3+ T cells to GPRC5D+ MM cells and induces killing of GPRC5D+ cells. In vitro, JNJ-64407564 induced specific cytotoxicity of GPRC5D+ cells with concomitant T-cell activation and also killed plasma cells in MM patient samples ex vivo. JNJ-64407564 can recruit T cells and induce tumor regression in GPRC5D+ MM murine models, which coincide with T-cell infiltration at the tumor site. This antibody is also able to induce cytotoxicity of patient primary MM cells from bone marrow, which is the natural site of this disease. GPRC5D is a promising surface antigen for MM immunotherapy, and JNJ-64407564 is currently being evaluated in a phase 1 clinical trial in patients with relapsed or refractory MM (NCT03399799).

Impact of Lenalidomide Maintenance Therapy on Immune Polarization and Activation in Multiple Myeloma

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2966-2966 ◽  
Author(s):  
Manisha Bhutani ◽  
David Foureau ◽  
Tammy Cogdill ◽  
Kyle Madden ◽  
Qing Zhang ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Maintenance Therapy ◽  
T Cell Activation ◽  
Research Funding ◽  
Cell Activation ◽  
Lymphoid Cells ◽  
Relative Distribution ◽  
The Impact

Abstract BACKGROUND: Lenalidomide is an immunomodulatory drug (IMiD) with co-stimulatory effects on immune effector cells in vitro and is an approved treatment for multiple myeloma (MM), although its mode of action in patients is not well defined. We studied the impact of lenalidomide maintenance therapy, following autologous stem cell transplant (ASCT), on NK and NK-T polarization (i.e. activating or inhibitory molecules) and, T cell activation (early vs. late activation) in patients with multiple myeloma. PATIENTS AND METHODS: In this ongoing prospective study with a targeted enrollment of 28 newly diagnosed multiple myeloma patients, blood samples are being collected at 2 to 3 months post ASCT, before starting lenalidomide maintenance therapy (baseline), and serially after 1, 3 and 6 months of treatment (T+1mo, T+3mo, T+6mo). Using a 9 color flow cytometry panel, peripheral blood samples were analyzed for expression of CD3 and CD56 to define NK (CD56+ CD3-), NKT (CD56+ CD3+), and T cell (CD56- CD3+) subsets. Killer 'inhibitory' Ig-like receptors, (KiR2DS4, KiR3DL1) natural killer group 2 proteins (NKG2a, NKG2D) and natural killer p46 protein (NKp46) expression were quantified to assess polarization of NK, and NK-T cells. Programmed death receptor 1 (PD-1) and T-cell Ig and mucin receptor 3 (Tim3) expression was quantified to assess T cell activation state. Flow cytometry data were acquired on a BD FACSAria II, and analyzed using FlowJo version X software. RESULTS: Samples from 11 patients have been collected and analyzed so far (11 baseline, 6 T+1mo, 4 T+3mo). At baseline lymphoid cells represent 12-46% of white blood cells (WBC), this heterogeneity being mainly driven by a wide range of T cell relative distribution among patients (30-74 % lymphoid cells). Phenotypically, NK cells at baseline mainly express natural cytotoxicity receptors (NKp46 and NKG2D), whereas NK-T cell also express NKG2D but approximately 1/3 also express PD-1 indicating they may be functionally defective. T cells at baseline express early T cell activation markers NKG2D and approximately 1/3 also stained positive for late T cell activation marker PD-1. Lymphoid cells relative distribution among WBC tends to normalize at T+1mo of treatment (15 to 35 % of WBC) before expanding at T+3mo (35 to 43 % of WBC). Phenotypically, across the 27 immune variables analyzed, each multiple myeloma patient displayed high level of immune homeostasis after 1 or 3 months of lenalidomide treatment. Noticeably, Nkp46 expression by NK cell and PD-1 expression by NK-T cells decreased in 4/6 patients and, NKG2D expression by T cell decreased in all but one patient during lenalidomide therapy. CONCLUSION: To our knowledge, this is the first study examining the influence of lenalidomide maintenance on the comprehensive immune repertoire in the post-ASCT setting in MM patients. The wide heterogeneity of NK, NK-T and T cell distribution observed at baseline among lymphoid cells indicates the potential effect of post-ASCT immune reconstitution and immunomodulatory the impact of lenalidomide. The capacity of lenalidomide to mediate effects on several immune cells raises the question as to which, if any, of these changes correlate with clinical responses. In our study, serially collected data from each patient, when completed would determine the impact of lenalidomide immunomodulatory effect of therapeutic efficacy and PFS duration in relation to immune reconstitution stage. Disclosures Cogdill: Millennium: Speakers Bureau; Onyx: Speakers Bureau; Celgene: Speakers Bureau; Novartis: Speakers Bureau. Ghosh:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Usmani:Sanofi: Honoraria, Research Funding; Millennium: Honoraria, Speakers Bureau; Onyx: Honoraria, Research Funding, Speakers Bureau; Pharmacyclics: Research Funding; Celgene: Honoraria, Speakers Bureau; Janssen Oncology: Honoraria, Research Funding; Array BioPharma: Honoraria, Research Funding.

New Insights into the Mechanism of Action (MoA) of First-in-Class IgG-Based Bcma T-Cell Bispecific Antibody (TCB) for the Treatment of Multiple Myeloma (MM)

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2096-2096 ◽  
Author(s):  
Laura Moreno ◽  
Aintzane Zabaleta ◽  
Diego Alignani ◽  
Marta Lasa ◽  
Patricia Maiso ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Research Funding ◽  
Cell Activation ◽  
Rational Combination ◽  
Dose Dependent ◽  
Tumor Cell Lysis

Abstract Novel agents have improved outcomes in MM, but prognosis after patients relapse remains poor and new drugs with novel MoA are needed. The breakthrough of immuno-oncology has rendered new therapeutic options, and most recently we reported on EM801, a novel BCMA-TCB that showed remarkably efficacy when used as single agent in primary bone marrow (BM) samples from MM patients (Seckinger, Blood 2015;126: abstr 117). Because of its novelty, further knowledge about the MoA of BCMA-TCB is of utmost importance to improve its efficacy by designing rational treatment combinations. In order to optimize the in vitro efficacy of the BCMA-TCB, we started by investigating in primary BM samples from 6 MM patients whether longer treatment periods with BCMA-TCB2 (a BCMA-TCB candidate sharing similar "2+1" structure of EM801 but displaying higher affinity to BCMA) would increase MM cell death. Upon treating samples with BCMA-TCB2 for 48h vs 96h, we noted a 2-fold increment in MM tumor cell lysis at 1nM and 10nM concentrations (Panel A). In parallel, the phenotypic profiles of CD4 and CD8 T cells showed that BCMA-TCB2 induced robust activation (ie. dose-dependent increment in CD69, CD25, HLADR after exposure to 100pM, 1nM and 10nM of BCMA-TCB2), but also led to the natural emergence of the checkpoint inhibitor PD-1 in the surface of activated CD4 and CD8 T cells (Panel B). We then investigated if there was a correlation between the percentage of PD-1 positive CD4 and CD8 T cells and the efficacy of BCMA-TCB2; interestingly, those patients with lower frequencies of PD-1 positive CD4 and CD8 T cells prior to treatment showed the highest rates of MM tumor cell lysis after 48h and 96h of BCMA-TCB2 at 10nM of (r=0.6, P=0.04; Panel C). By contrast, upon measuring the concentration of soluble BCMA and APRIL in the supernatants of primary BM samples from 16 MM patients treated with BCMA-TCB, we found no significant differences between responding (n=11) and non-responding (n=5) patients. Similar results were observed upon comparing the density of BCMA in the surface of MM tumor cells from responding vs non-responding patients (1256 vs 1522 SABC units; P=87). Since the efficacy of BCMA-TCB2 was found to be intrinsically related to the phenotype and activation status of T cells, we then investigated whether we could further harness immune cells by combining BCMA-TCB2 with three drugs representing different types of immunotherapy: lenalidomide (IMIDs), anti-PD1 (checkpoint inhibitors) and daratumumab (mAb). H929 MM cells were co-cultured with human leukocytes (n=5) and challenged to suboptimal concentrations of BCMA-TCB2 (10pM) alone, or in combination with standard doses of lenalidomide (1µM), anti-PD1 (10µg/ml) and daratumumab (10µg/ml) (Panel D). Interestingly, we observed that combining BCMA-TCB2 with lenalidomide or daratumumab significantly increased their anti-MM efficacy by 4-fold and 2.5-fold, respectively. Because lenalidomide and daratumumab share in common that they rely, at least in part, on activated NK cells to eradicate MM cells, we hypothesized whether such robust T cell activation induced by BCMA-TCB2 was leading to co-stimulation of NK cells. First, we demonstrated by analyzing the transcriptomes of T cells prior and after treatment exposure (n=3), that BCMA-TCB2 modulated the transcriptomes of CD4 and CD8 T cells (159 and 141 deregulated genes, respectively), consistent with enhanced activation and T-cell mediated inflammatory response (eg. TNFRS18, STAT1, CCL4). Furthermore, we observed a dose-dependent and significant increment of the CD69 (2-fold), CD25 (2.5-fold) and HLADR (4-fold) activation markers in the surface of NK cells from primary BM samples of 11 MM patients treated with BCMA-TCB2 (Panel E), suggesting a functional crosstalk between activated T cells and NK cells. In conclusion, we showed that the promising pre-clinical activity of the first-in-class IgG-based BCMA-TCB can be further enhanced by longer treatment periods followed by robust T cell activation. The observation that the efficacy of BCMA-TCB is intrinsically related to the activation status of T cells suggests its rational combination with IMIDs as demonstrated here. Most interestingly, potential crosstalk between activated T and NK cells could lead to enhanced function of the later immune subset, and provide a rational combination between BCMA-TCB and anti-CD38 antibodies to eradicate MM cells through highly activated T and NK cells. Figure Figure. Disclosures Strein: EngMab: Employment. Vu:EngMab: Employment. Paiva:Celgene: Honoraria, Research Funding; Janssen: Honoraria; Takeda: Honoraria, Research Funding; Sanofi: Consultancy, Research Funding; EngMab: Research Funding; Amgen: Honoraria; Binding Site: Research Funding.

Preclinical evaluation of AMG 160, a next-generation bispecific T cell engager (BiTE) targeting the prostate-specific membrane antigen PSMA for metastatic castration-resistant prostate cancer (mCRPC).

2019 ◽  
Vol 37 (7_suppl) ◽  
pp. 301-301 ◽  
Author(s):  
Julie Bailis ◽  
Petra Deegen ◽  
Oliver Thomas ◽  
Pamela Bogner ◽  
Joachim Wahl ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cells ◽  
T Cell Activation ◽  
Half Life ◽  
Cell Activation ◽  
Phase 1 ◽  
Xenograft Model ◽  
Cytokine Release ◽  
Single Chain

301 Background: mCRPC is a disease of high unmet medical need, especially for patients who fail novel hormonal therapies and chemotherapy. BiTE molecules provide an off the shelf therapy that activates a patient’s own immune system and redirects T cells to kill tumor cells. The BiTE mechanism of action is distinct from other immunotherapies and may unlock immune response in mCRPC. PSMA is a compelling BiTE target that is highly expressed on PCa compared to normal tissue and has increased expression in mCRPC. Methods: AMG 160 is a fully human, half-life extended (HLE) BiTE that targets PSMA on tumor cells and CD3 on T cells. AMG 160 comprises two tandem single chain variable fragments fused to an Fc domain. Results: AMG 160 binds human and non-human primate (NHP) PSMA and CD3, leading to T cell activation and proliferation and cytokine production. AMG 160 redirects T cells to kill PSMA-positive cancer cell lines in vitro, including those with low PSMA levels or androgen-independent signaling. Weekly dosing of AMG 160 induces significant antitumor activity in established PCa xenograft model. The pharmacokinetics (PK) and pharmacodynamics of AMG 160 were tested in NHP. AMG 160 treatment led to BiTE target engagement in vivo, including transient T cell activation and cytokine release in blood, and mixed cellular infiltrates in multiple organs known to express PSMA. AMG 160 treatment was well tolerated. Cytokine release associated with the first dose could be attenuated using a step dose regimen. The half-life of AMG 160 in NHP was about one week. Based on allometric scaling, the PK profile of AMG 160 may be projected to enable dosing every other week in humans. Conclusions: AMG 160 is a potent HLE BiTE with specificity for PSMA-positive tumor cells. A Phase 1 study is planned to evaluate the safety and efficacy of AMG 160 in patients with mCRPC.

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

Blood ◽  
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.

scholarly journals Local Activator and T Cell Engager (αBCMA x αPD-L1 x αCD3) with Enhanced Tumor Killing and Minimal Cytokine Release for the Treatment of Multiple Myeloma

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 20-20
Author(s):  
Melissa Vrohlings ◽  
Stephanie Jungmichel ◽  
Jan Müller ◽  
David Senn ◽  
Thomas Schleier ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Tumor Cell ◽  
Cell Lines ◽  
T Cell Activation ◽  
Research Funding ◽  
Cell Activation ◽  
Cytokine Release ◽  
Private Company

BCMA-targeting bispecific T-cell engagers in clinical development have demonstrated encouraging preclinical efficacy. The most advanced of these is AMG 420, which showed significantly improved response rates in relapsed/refractory multiple myeloma (MM) patients. Nevertheless, median duration until relapse is currently limited to approximately 12 months, highlighting the need for new drugs with novel MoA. Recently, we reported on a Local Activator and T cell Engager (LocATE) antibody that targets BCMA and selectively blocks programmed death-ligand 1 (PD-L1) on malignant cells (ASCO, June 2019). LocATE induced superior T cell activation and cancer cell killing, in vitro and ex vivo, compared to a BCMAxCD3 BiTE alone or in combination with a PD-L1 inhibitor. Here, we sought to further characterize the novel MoA of our LocATE. To assess the therapeutic potential of the LocATE, we first investigated whether potent cytotoxicity is uncoupled from high levels of cytokine release. We evaluated three LocATE molecules with different PD-L1 affinities (low, medium, high). Using BCMA-expressing MM cell lines (U-266, MM.1S, RPMI-8226 and H929) with distinct PD-L1 surface expression levels (3 - 53%), we determined the cytokine profile (IL-2, IL-6, IFN-γ, TNF-α) and target cell lysis induced by each candidate in the presence of CD3-positive human T cells. All three candidates exhibited comparable killing potency, however, low-affinity PD-L1 LocATE antibodies induced significantly less cytokine release (up to 10-fold) than its higher PD-L1 affinity counterparts across all cell lines investigated. Notably, using the low-affinity PD-L1 LocATE, we observed a 2-fold increase in tumor cell killing compared to bispecific BCMAxCD3 targeting controls in cell lines expressing high PD-L1 levels (53%), underlining the contribution of PD-L1 inhibition. Accordingly, phenotypic profiling of effector cells showed that the LocATE more potently induced dose-dependent upregulation of the activation markers CD69, CD25 and HLA-DR compared to bispecific controls. Importantly, cytotoxic activity, T cell activation and cytokine release were not induced when BCMA-negative cells expressing high levels of PD-L1 were treated with LocATE, underlining the BCMA-selective killing mechanism. Since the superior efficacy of LocATE was found to correlate with the expression level of PD-L1 on MM cell lines and upregulation of PD-L1/PD-1 has been reported as one of the major myeloma cell escape mechanisms during treatment with BiTEs, we subsequently investigated the efficacy of LocATE using primary bone marrow samples and peripheral blood mononuclear cell (PBMCs) obtained from MM patients. Six bone marrow mononuclear cell (BMMC) and eight PBMC samples from MM donors of different disease stages were characterized for PD-1/PD-L1 expression levels; analysis of T cell frequency and level of activation/exhaustion was performed based on CD4, CD8, CD25, CD69, Tim-3, Lag-3 and PD-1 marker expression. Using patient samples with high frequencies of PD-1 expressing T cells prior to treatment, LocATE induced superior MM tumor cell lysis and T cell activation compared to BCMAxCD3 bispecific antibodies. No activity was observed on healthy cells, underlining the safe and selective killing mechanism through tumor-local reactivation of exhausted T cells. Collectively, these findings demonstrate that the simultaneous T cell redirection and tumor-specific checkpoint inhibition with the LocATE leads to an improved therapeutic index with robust tumor cell killing and low levels of cytokine release. Capable of counteracting adaptive immune resistance caused by increased PD-1/PD-L1 signaling, the LocATE antibody has the prospect to significantly improve survival for multiple myeloma patients. Disclosures Vrohlings: CDR-Life: Current Employment. Jungmichel:CDR-Life: Current Employment, Other: current option holder. Senn:CDR-Life: Current Employment. Schleier:CDR-Life: Current Employment, Current equity holder in private company. Scheifele:CDR-Life: Current Employment, Current equity holder in private company. Wendelspiess:CDR-Life: Current Employment. Leisner:CDR-Life: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees. Jaeger:CDR Life AG: Consultancy, Research Funding; Miltenyi: Consultancy, Honoraria; Karyopharm: Honoraria; BMS/Celgene: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; AbbVie: Honoraria; F. Hoffmann-La Roche: Honoraria, Research Funding. Borras:CDR-Life: Current Employment, Current equity holder in private company.

Clinical Efficacy of Anti-CD22 Chimeric Antigen Receptor T Cells for B-Cell Acute Lymphoblastic Leukemia Is Correlated with the Length of the Scfv Linker and Can be Predicted Using Xenograft Models

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 807-807
Author(s):  
Marco Ruella ◽  
Shannon L Maude ◽  
Boris Engels ◽  
David M. Barrett ◽  
Noelle Frey ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Board Of Directors ◽  
T Cell Activation ◽  
Research Funding ◽  
Cell Activation ◽  
Lymphoblastic Leukemia ◽  
Advisory Committees ◽  
Xenograft Models

Abstract Introduction. Anti-CD19 chimeric antigen receptor T cells (CART19 or CTL019) have shown impressive clinical activity in B-cell acute lymphoblastic leukemia (B-ALL) and are poised to receive FDA approval. However, some patients relapse after losing CD19 expression. Since CD22 remains highly expressed in relapsed/refractory (r/r) B-ALL even in these patients, anti-CD22 CART (CART22) have been developed. The National Cancer Institute (NCI) reported 4/9 complete remission (CR) in patients receiving CART22, with 100% CR at the highest T cell dose (NCT02315612)(S hah NN, ASH 2016 #650). Patients and Methods. We generated a second-generation CAR22 differing from that used by the NCI only by the use of a longer linker [4x(GGGGS); LL vs. 1x(GGGGS); SL] between the light and heavy chains of the scFv (Fig. 1 A). This construct was tested in two pilot clinical trials in adults (NCT02588456)and children with r/r-ALL (NCT02650414). CART22 cells were generated using lentiviral transduction as in our previous studies. The protocol-specified CART22 dose was 2x106-1x107 cells/kg for pediatric patients <50kg and 1-5x108 for pediatric patients ≥50kg and adult patients,. infused after lymphodepleting chemotherapy. Patient characteristics are described in Table 1. For the adult trial, 5 patients were screened, 4 enrolled (1 patient withdrew consent) and 3 infused (1 manufacturing failure). For the pediatric trial, 9 patients were screened, 8 enrolled (1 screen failure) and 6 infused (two patients were not infused for disease progression). For the preclinical studies, we generated CART22LL and CART22SL and tested them in vivo using xenograft models. NOD-SCID gamma chain deficient (NSG) mice were engrafted with either a luciferase+ standard B-ALL cell line (NALM6) or primary B-ALL cells obtained from a patient relapsing after CART19 (CHP110R). We also used 2-photon imaging to study the in vivo behavior and immune synapse formation and flow cytometry to asses T cell activation. Results. CART22 cells were successfully manufactured for 10/12 patients. In the adult cohort 3/3 patients developed CRS (gr.1-3) and no neurotoxicity was observed; in the pediatric cohort out of 5 evaluable patients (1 discontinued for lineage switch to AML on pre-infusion marrow), 3/5 developed cytokine-release syndrome (CRS) (all grade 2) and 1 patient had encephalopathy (gr.1). CART22 cells expanded in the PB with median peak of 1977 (18-40314) copies/ug DNA at day 11-18. Interestingly, in an adult patient who had previously received CART19 a second CART19 re-expansion was observed following CART22 expansion (Fig 1 B). At day 28, in the adult cohort the patient who was infused in morphologic CR remained in CR, while the other 2 had no response (NR); in the pediatric cohort 2/5 patients were in CR, 1 in partial remission (PR) that then converted to CR with incomplete recovery at 2 months, and 2 NR. No CD22-negative leukemia progression was observed. Since our results with a long linker appeared inferior compared to the previously reported CART22 trial (short linker), we performed a direct comparison of the 2 different CAR22 constructs. In xenograft models, CART22SL significantly outperformed CART22LL (Fi 1 C) with improved overall survival. Moreover, CART22SL showed higher in vivo proliferation at day 17 (Fig 1 D). Mechanistically, intravital 2-photon imaging showed that CART22SL established more protracted T cell:leukemia interactions than did CART22LL, suggesting the establishment of productive synapses (Fig 1 E). Moreover, in vivo at 24 hrs higher T cell activation (CD69, PD-1) was observed in CART22SL from the BM of NALM-6-bearing mice. Conclusions. Here we report the results of two pilot clinical trials evaluating the safety and feasibility of CART22 therapy for r/r B-ALL. Although feasible and with manageable toxicity CART22LL led to modest clinical responses. Preclinical evaluation allowed us to conclude that shortening the linker by 15 amino acids significantly increases the anti-leukemia activity of CART22, possibly by leading to more effective interactions between T cells and their targets. Finally, with the caveats of cross-trial comparison, our data suggest that xenograft models can predict the clinical efficacy of CART products and validate the use of in vivo models for lead candidate selection Disclosures Ruella: Novartis: Patents & Royalties, Research Funding. Maude: Novartis Pharmaceuticals: Consultancy, Other: Medical Advisory Boards. Engels: Novartis: Employment. Frey: Novartis: Research Funding. Lacey: Novartis: Research Funding; Genentech: Honoraria. Melenhorst: Novartis: Research Funding. Brogdon: Novartis: Employment. Young: Novartis: Research Funding. Porter: Incyte: Honoraria; Novartis: Honoraria, Patents & Royalties, Research Funding; Immunovative Therapies: Other: Member DSMB; Genentech/Roche: Employment, Other: Family member employment, stock ownship - family member; Servier: Honoraria, Other: Travel reimbursement. June: WIRB/Copernicus Group: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celldex: Honoraria, Membership on an entity's Board of Directors or advisory committees; Immune Design: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Novartis: Patents & Royalties, Research Funding; Tmunity Therapeutics: Equity Ownership, Research Funding. Grupp: Jazz Pharmaceuticals: Consultancy; Novartis Pharmaceuticals Corporation: Consultancy, Other: grant; University of Pennsylvania: Patents & Royalties; Adaptimmune: Consultancy. Gill: Novartis: Patents & Royalties, Research Funding.

scholarly journals Chronic Lymphocytic Leukemia Actively Induces T-Cell Dysfunction By Contact-Dependent Signaling Via CD24 and CD52

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3714-3714
Author(s):  
Jaco A. C. Van Bruggen ◽  
Fleur Peters ◽  
Gaspard Cretenet ◽  
J. Joseph Melenhorst ◽  
Eric Eldering ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Research Funding ◽  
Cell Activation ◽  
Cell Function ◽  
Cell Dysfunction ◽  
T Cell Function ◽  
Car T ◽  
T Cell Dysfunction

Abstract Introduction Success rates of autologous T cell-based therapies, such as CAR-T cell therapy, in chronic lymphocytic leukemia (CLL) have been suboptimal and correlate with failure of activation and proliferation of T cells in vitro and in vivo. Previous data showing that impaired CD8 T-cell activation, proliferation and metabolic reprogramming could be restored by purifying CLL T cells via cell-sorting (van Bruggen et al., Blood, 2019) indicating that an as yet unknown, CLL-derived factor is responsible for acquired T-cell dysfunction. In this study we aim to elucidate the mechanistic basis of CLL-mediated T-cell dysfunction. Results Dynamic analysis of αCD3/CD28 stimulated autologous T cells in presence of CLL cells over a period of 9 days revealed that T-cell activation (CD25, CD71, CD95 and PD-1) in CLL is in fact not impaired but occurs in a delayed fashion. CLL T cells reached peak activation after 5-6 days in contrast to 2-3 days for age-matched healthy donors. (Fig. 1A). This delayed T cell receptor-induced T cell activation was largely normalized with tumor cell depletion by flow-sorting prior to activation. Accordingly, in absence versus presence of autologous CLL cells, CAR-T cells derived from CLL patients showed enhanced proliferation, cytokine production and cytotoxicity, indicating potential clinical relevance. These findings show that T cells in CLL are not (terminally) exhausted but that a CLL-derived factor interferes with proper T-cell activation, leading to a delay in activation and impaired proliferation and cytotoxicity. We attempted to identify the mechanism of action in which CLL cells induce T cell dysfunction and whether these suppressive effects are mediated through a soluble factor secreted by CLL cells or by contact-dependent mechanisms. Previous studies have shown that CD40 activation of CLL cells results in increased expression of key surface-expressed adhesion and costimulatory molecules, but also in alterations of immune-modulatory cytokines secretion. This model was therefore used to decipher mechanisms of CLL-mediated T cell dysfunction. CD40-activation of CLL cells resulted in improved T-cell activation and proliferation upon αCD3/CD28 stimulation in a contact-dependent manner (based on trans-well experiments; Fig. 1B ). Several clinically approved kinase inhibitors were tested to identify signaling cascades involved in CD40-mediated alleviation of T-cell dysfunction. Only pre-treatment of CLL cells with the SRC-inhibitor dasatinib (100nM) abrogated the enhanced T-cell activation induced by CD40-activated CLL cells. Additional control experiments excluded direct effects of dasatinib on T cell function. Dasatinib did not reduce expression of co-stimulatory markers on CD40-activated CLL cells, indicating that lack of co-stimulation was not the sole explanation for CLL-mediated T cell dysfunction. RNA sequencing of CD40-stimulated CLL cells treated with or without dasatinib and filtered for membrane-bound factors revealed the Sialic acid-binding Ig-like lectin 10 (Siglec-10) ligands CD24 and CD52 as potential candidates responsible for inhibiting T-cell function in CLL, which we confirmed at the protein level. We also found increased expression of Siglec-10 on CLL T cells, suggesting a role for Siglec-10 ligation in inhibition of the TCR signaling cascade. Indeed, inhibition of Siglec-10 ligation by blocking CD24, and CD52 antibodies subsequently improved T-cell activation despite presence of CLL cells (Fig. 1C). Conclusion These results demonstrate that T cells derived from CLL patients are not terminally dysfunctional and can be revived. Our observations indicate that CLL cells actively suppress (CAR) T-cell function in a contact-dependent fashion through CD24- and CD52-mediated Siglec-10 ligation. These proteins might represent targets for therapeutic intervention aimed at enhancing T-cell function in CLL. Figure 1 Figure 1. Disclosures Kater: Genmab, LAVA: Other: Ad Board, Steering Committee; Abbvie: Honoraria, Other: Ad Board, Research Funding; Janssen, AstraZeneca: Other: Ad Board, steering committee, Research Funding; BMS, Roche/Genentech: Other: Ad Board, , Research Funding.

scholarly journals Adult Patients with ALL Treated with CD62L+ T Naïve/Memory-Enriched T Cells Expressing a CD19-CAR Mediate Potent Antitumor Activity with a Low Toxicity Profile

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4016-4016 ◽  
Author(s):  
Samer K. Khaled ◽  
Suzette Blanchard ◽  
Xiuli Wang ◽  
Jamie Wagner ◽  
Araceli Naranjo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Research Funding ◽  
Disease Burden ◽  
Phase 1 ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T ◽  
Manufacturing Platform ◽  
Grade 3

Abstract Introduction: Treatment of adults with relapsed/refractory (R/R) B-ALL using CD19-targeted chimeric antigen receptor (CAR) T cells has achieved remarkable remission rates, both in pediatric and adult populations. There are multiple CAR constructs and T cell manufacturing platforms in use, and both aspects of the therapy may impact efficacy and toxicity. Park et al. report that 83% of adult patients (pts) achieve complete response (CR) to their CD19 CAR T cells with a CD28 costimulatory domain (NEJM; 3785: 449), using an unselected peripheral blood (PBMC) manufacturing platform. Unfortunately, therapy-associated toxicities in adult and pediatric ALL pts are problematic, with grade 3/4 cytokine release syndrome (CRS) ranging from 26-49 % and neurotoxicity 18-42%. Here we report preliminary data from one arm of a phase 1 clinical trial (NCT02146924) in adult pts with R/R B-ALL testing a memory-enriched T cell starting population engineered to express a CD19-specific, CD28-costimulatory CAR (CD19:28z-CAR). All pts achieved CR or CRi with a low incidence of severe cytokine release syndrome (CRS) and neurotoxicity. Unique to this study is our Tn/mem-enriched manufacturing platform, a naïve/memory T cell-enriched T cell product that is lentivirally transduced to express our CD19:28z-CAR. The manufacturing process starts with patient PBMC, depletes the CD14+ monocytes and CD25+ Tregs, and selects for CD62L+ T cells. The resultant T cell population for CAR transduction includes both the central memory and stem cell memory populations along with naïve T cells. Preclinical studies in mice had suggested that using a more uniform T cell product with a less-differentiated T cell phenotype improved antitumor activity. This Tn/mem manufacturing platform is the same as our Tcm-derived platform (Blood;127:2980) except that CD45RA depletion was omitted. Patients and Methods: This phase I study used the activity constrained for toxicity (ACT) design, an extension of the toxicity equivalence range (TEQR) design of Blanchard and Longmate (Contemp Clin Trials; 32:114), that dose escalates based on lack of activity, while constraining the dose for toxicity. The primary objectives of this study were to test the safety and activity of Tn/mem-enriched CD19:28z CAR T cells, and to determine the phase 2 recommended dose. The primary endpoints were toxicity and disease response. Sixteen pts were consented and received a lymphodepleting regimen (LDR) of 1.5-3 gm/m2 cyclophosphamide over 2-3 days and 25-30 mg/m2 fludarabine for 3 days. Three pts received LDR, but did not receive T cells due to infection or lack of CD19+ disease. Patients received a flat dose of 200 million (M) CD19:28z-CAR T cells: 11 autologous and 2 allogeneic donor products. Of the 13 that received 200 M CAR+ T cells, 2 pts were deemed ineligible for dose escalation / disease response evaluation, as 1 received <80% of the prescribed dose (100 M) and the other had CD19-negative extramedullary disease. The median age of the 13 CAR T cell treated pts was 33 years (24-72). All pts had active bone marrow (BM) disease at the time of LDR: 8 pts (62%) had high disease burden (15-91% BM blasts) and 5 had low disease burden (</= 5% BM blasts). Patients were heavily pretreated, with a median of 5 (2-6), prior regimens. Six pts received prior allogeneic transplant (HSCT), 9 had prior blinatumomab, and 1 had prior CD19 CAR T cells. Results: Toxicity: Table 1 describes the major toxicities of the 13 CAR-treated pts, stratified based on disease burden. There were no DLTs, and T-cell therapy attributed (>/=possibly) toxicities were typically mild and reversible. Eight pts had grade 2 CRS, and 2 had grade 3 CRS. Three pts had grade 2 neurotoxicity and 2 had grade 3. Response: Eleven pts were evaluable for response, with best response of 4 CRs (MRD- by flow) and 7 CRi (6 MRD-, 1 not tested). Median response duration at last contact or HSCT start was 81 days (39-286); 8 pts proceeded to HSCT (in CR or CRi) at a median of 69 days post-CAR infusion (39-103). Conclusions: Our ongoing phase 1 trial demonstrates a 100% response rate to Tn/mem-enriched CD19:28z-CAR T cell therapy in adults with relapsed/refractory (R/R) B-ALL. Although the numbers are small, the unanimous response, combined with a tolerable and reversible toxicity profile in pts with both low and high disease burden is remarkable and suggests promise for this Tn/mem manufacturing platform for CD19 and other CAR targets. Disclosures Khaled: Juno: Other: Travel Funding; Daiichi: Consultancy; Alexion: Consultancy, Speakers Bureau. Wang:Mustang Therapeutics: Other: Licensing Agreement, Patents & Royalties, Research Funding. Brown:Mustang Therapeutics: Consultancy, Other: Licensing Agreement, Patents & Royalties, Research Funding. Forman:Mustang Therapeutics: Other: Licensing Agreement, Patents & Royalties, Research Funding.

scholarly journals 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 ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5319-5319 ◽  
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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