scholarly journals Potent and selective antitumor activity of a T cell-engaging bispecific antibody targeting a membrane-proximal epitope of ROR1

2018 ◽  
Vol 115 (24) ◽  
pp. E5467-E5476 ◽  
Author(s):  
Junpeng Qi ◽  
Xiuling Li ◽  
Haiyong Peng ◽  
Erika M. Cook ◽  
Eman L. Dadashian ◽  
...  

T cell-engaging bispecific antibodies (biAbs) present a promising strategy for cancer immunotherapy, and numerous bispecific formats have been developed for retargeting cytolytic T cells toward tumor cells. To explore the therapeutic utility of T cell-engaging biAbs targeting the receptor tyrosine kinase ROR1, which is expressed by tumor cells of various hematologic and solid malignancies, we used a bispecific ROR1 × CD3 scFv-Fc format based on a heterodimeric and aglycosylated Fc domain designed for extended circulatory t1/2 and diminished systemic T cell activation. A diverse panel of ROR1-targeting scFv derived from immune and naïve rabbit antibody repertoires was compared in this bispecific format for target-dependent T cell recruitment and activation. An ROR1-targeting scFv with a membrane-proximal epitope, R11, revealed potent and selective antitumor activity in vitro, in vivo, and ex vivo and emerged as a prime candidate for further preclinical and clinical studies. To elucidate the precise location and engagement of this membrane-proximal epitope, which is conserved between human and mouse ROR1, the 3D structure of scFv R11 in complex with the kringle domain of ROR1 was determined by X-ray crystallography at 1.6-Å resolution.

2017 ◽  
Author(s):  
Junpeng Qi ◽  
Xiuling Li ◽  
Haiyong Peng ◽  
HaJeung Park ◽  
Christoph Rader

AbstractT-cell engaging bispecific antibodies present a promising strategy for cancer immunotherapy and numerous bispecific formats have been developed for retargeting cytolytic T cells toward tumor cells. To explore the therapeutic utility of T-cell engaging bispecific antibodies targeting the receptor tyrosine kinase ROR1, which is expressed by tumor cells of various hematologic and solid malignancies, we used a bispecific ROR1 × CD3 scFv-Fc format based on a heterodimeric and aglycosylated Fc domain designed for extended circulatory half-life and diminished systemic T-cell activation. A diverse panel of ROR1-targeting scFv derived from immune and naïve rabbit antibody repertoires was compared in this bispecific format for target-dependent T-cell recruitment and activation. A ROR1-targeting scFv with a membrane-proximal epitope, R11, revealed potent and selective antitumor activity in vitro and in vivo and emerged as a prime candidate for further preclinical and clinical studies. To elucidate the precise location and engagement of this membrane-proximal epitope, which is conserved between human and mouse ROR1, the three-dimensional structure of scFv R11 in complex with the kringle domain of ROR1 was determined by X-ray crystallography at 1.6-Å resolution.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A904-A904
Author(s):  
Louise Koopman ◽  
Laura Smits-de Vries ◽  
Frederikke Lihme Egerod ◽  
Sebastiaan Wubben ◽  
Mischa Houtkamp ◽  
...  

BackgroundThe immune checkpoint protein B7H4 is expressed on malignant cells in various solid cancers, whereas its expression is highly restricted in normal tissue. B7H4 is therefore an attractive target for a CD3 bispecific antibody (bsAb) therapeutic. Moreover, its expression is reported to be inversely correlated with PD-L1. Here, we describe the preclinical characterization of two B7H4-targeting CD3 bsAbs with different CD3 affinities, supporting the selection of our clinical lead, DuoBody-CD3xB7H4 (GEN1047).MethodsB7H4 protein expression in patient-derived samples was determined by immunohistochemistry. Controlled Fab-arm exchange of an Fc-silenced B7H4 antibody with two Fc-silenced CD3ε-binding antibodies generated two CD3xB7H4 bsAbs that differ in CD3 binding affinity by approximately 30-fold. In vitro T-cell mediated cytotoxicity, T-cell activation, and cytokine release were assayed using cocultures of B7H4-expressing tumor cells and healthy donor T cells. Nonclinical safety (NCS) of the two CD3xB7H4 bsAbs was assessed in cynomolgus monkeys, and antitumor activity of the clinical lead in vivo was tested in a patient-derived xenograft (PDX) screen in mice with a humanized immune system (HIS).ResultsB7H4 protein expression was confirmed in tumor biopsies from multiple indications, including breast, ovarian and lung cancer. Both bsAbs induced target-specific and dose-dependent tumor cell kill in vitro. Maximal kill and T-cell activation were comparable for both variants, although the potency of the high CD3 affinity bsAb was higher. However, production of inflammatory cytokines at comparable effective concentrations (IC90) was lower for the low CD3 affinity bsAb. Single dose NCS studies in cynomolgus monkeys showed that both CD3xB7H4 bsAbs were well-tolerated. A dose-dependent increase in plasma cytokines IL-6 and MCP-1 2 hours after dosing was observed only with the high CD3 affinity bsAb. Based on these findings, the low CD3 affinity bsAb was selected for follow-up studies and named DuoBody-CD3xB7H4 (GEN1047). DuoBody-CD3xB7H4 demonstrated antitumor activity in vivo in a PDX screen in HIS mice. Repeated dosing of DuoBody-CD3xB7H4 in cynomolgus monkeys confirmed an acceptable safety profile up to the maximal dose tested (30 mg/kg).ConclusionsThese studies describe the preclinical development of DuoBody-CD3xB7H4, a bsAb that induces T-cell mediated cytotoxicity of B7H4-positive tumor cells, which may provide an alternative therapeutic modality in the immune-oncology space for patients with solid cancers.Ethics ApprovalAnimal experiments were performed according to the guidelines of the Institutional Animal Care and Use Committee (IACUC) and in accordance with the regulations of the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC). NCS studies were conducted at Citoxlab (Evreux, France) and Charles River Laboratories (Tranent, UK) in accordance with the European Convention for the Protection of Vertebrate Animals Used for Experimental and Other Scientific Purposes (Council of Europe).


2015 ◽  
Vol 33 (3_suppl) ◽  
pp. 262-262
Author(s):  
David M. Goldenberg ◽  
Edmund A. Rossi ◽  
Diane L Rossi ◽  
Thomas M. Cardillo ◽  
Chien-Hsing Chang

262 Background: Trop-2 [also called tumor-associated calcium signal transducer 2 (TACSTD2), EGP-1 (epithelial glycoprotein-1), GA733-1, or M1S1]is a 35 kDa transmembrane glycoprotein that is overexpressed relative to normal tissues in a variety of human cancers, including pancreatic and gastric carcinomas, where increased expression correlates with poor prognosis. Trop-2 appears to be more tumor-specific than the related molecule, EpCAM (Trop-1). MT110, the EpCAM antibody x CD3 bispecific T-cell engager (BiTE), is currently undergoing a Phase I study in various solid tumors, including lung, gastric, colorectal, breast, prostate, and ovarian cancers. We produced a similar T-cell redirecting bispecific tandem scFv, E1-3, using the variable domains of hRS7 (humanized anti-Trop-2 mAb) and Okt-3 (anti-CD3 mAb). Methods: T-cell activation, cytokine induction and cytotoxicity were evaluated ex vivo using PBMCs or purified T cells with human pancreatic (Capan-1 and BxPC3) and gastric (NCI-N87) cancer cell lines as target cells. In vivo activity was assayed with NCI-N87 xenografts that were inoculated s.c. in a mixture with twice the number of human PBMCs and matrigel. Results: In the presence of target cells and PBMCs, E1-3 potently induced T-cell activation, proliferation, and dose-dependent cytokine production of IL-2 (>2 ng/mL), IL-6 (>1 ng/mL), IL-10 (>7 ng/mL), TNF-α (>1 ng/mL) and IFN-γ (>50 ng/mL). In vitro, E1-3 mediated a highly potent T-cell lysis of BxPC3 [IC50=0.09(±0.04) pM], Capan-1 [IC50=1.2(±1.1) pM] and NCI-N87 [IC50=1.2(±1.2) pM] target cells. In vivo, two 50-µg doses of E1-3 given three days apart cured all of the mice (N=8) bearing NCI-N87 xenografts (P=0.0005; Log-Rank). Tumors in the control group (PBMCs only) reached the endpoint (TV>1 cm3) with a median of 39.5 days. All mice remained tumor-free in the E1-3 group at 78 days. Conclusions: Trop-2 is an attractive target for T-cell-mediated killing of pancreatic, gastric and other epithelial cancers.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A587-A587
Author(s):  
Diego Alvarado ◽  
Laura Vitale ◽  
Mike Murphy ◽  
Thomas O’Neill ◽  
Edward Natoli ◽  
...  

BackgroundAxl is a member of the TAM (Tyro3/Axl/MerTK) family of receptor tyrosine kinases and a negative regulator of innate immunity. Activation of Axl through its ligand Gas6 leads to suppression of myeloid cell activity, while its activation in tumor cells drives tumor growth, metastasis, and is associated with acquired resistance to targeted therapies, radiotherapy and chemotherapy.MethodsPurified monoclonal antibodies and variants thereof were tested in human cancer lines and primary human myeloid cells for effects on Axl signaling and immune activation, respectively.ResultsWe describe a humanized IgG1 Axl-targeting monoclonal antibody (mAb), CDX-0168, that binds to the ligand-binding domain of Axl with sub-nanomolar affinity and potently inhibits Gas6 binding. In tumor cells, CDX-0168 inhibits Gas6-dependent Axl phosphorylation and signaling and elicits tumor cell killing via ADCC in vitro and in vivo. In primary human immune cells, CDX-0168 treatment induces potent release of pro-inflammatory cytokines and chemokines from dendritic cells, monocytes and macrophages through an Fc receptor-dependent mechanism and enhanced T cell activation in mixed lymphocyte reactions. Axl inhibition may further enhance antitumor activity associated with PD-(L)1 blockade. To this end, we generated a tetravalent bispecific Axl x PD-L1 antibody combining CDX-0168 with a potent anti-PD-L1 mAb (9H9) using an IgG-scFv format. The bispecific antibody elicits greater cytokine release and T cell activation in vitro than the combination of the parental antibodies, while maintaining robust Axl and PD-L1 blockade.ConclusionsAdditional studies investigating simultaneous blockade of the Axl and PD-L1 pathways with other agents may further exploit the potential for this novel anti-cancer therapeutic approach.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A928-A928
Author(s):  
Steve Sazinsky ◽  
Phuong Nguyen ◽  
Mohammad Zafari ◽  
Ryan Phennicie ◽  
Joe Wahle ◽  
...  

BackgroundVSIG4 (V-set immunoglobulin-domain-containing 4) is a B7 family related protein with known roles as a complement receptor involved in pathogen clearance as well as a negative regulator of T cell activation by an undetermined mechanism.1–3 VSIG4 is expressed in tumor associated macrophages (TAMs) with exquisite specificity. In cancer, increased expression of VSIG4 has been associated with worse survival in multiple indications, including non-small cell lung cancer, multiple myeloma, ovarian cancer, and glioma, suggesting an important role in tumor immune evasion.3–6 Based upon computational analysis of transcript data across thousands of primary cancer and normal tissue samples, we hypothesized that VSIG4 has an important regulatory role in promoting M2-like immune suppressive macrophages in the tumor microenvironment, and that targeting VSIG4 via a monoclonal antibody could relieve VSIG4-mediated macrophage suppression by repolarizing TAMs to an inflammatory phenotype capable of coordinating an anti-tumor immune response.MethodsThe ability of anti-VSIG4 antibodies to repolarize M2-like macrophages and induce T cell activation was assessed in vitro and ex vivo, by measuring production of inflammatory mediators. In vitro assays were performed primarily with M-CSF plus IL-10 driven monocyte-derived M2c macrophages from healthy donors. Ex vivo assays were performed with fresh, patient-derived tumor samples in culture. To determine whether targeting VSIG4 can lead to an anti-tumor effect in vivo, syngeneic mouse models were dosed with anti-mouse VSIG4 antibodies and characterized for changes in tumor volume and immune cell populations.ResultsIn in vitro and ex vivo assays anti-VSIG4 antibodies repolarize M2 macrophages and induce an immune response culminating in T cell activation. Targeting VSIG4 upregulates pro-inflammatory cytokines in M2c macrophages, as well as upregulates pro-inflammatory myeloid-derived cytokines and T cell-derived cytokines in M2c macrophages co-cultured with autologous T cells in the presence of staphylococcal enterotoxin B (SEB) activation. To assess targeting VSIG4 in a relevant translational model, fresh, patient-derived tumor samples were treated ex vivo with anti-VSIG4. Across multiple tumor types, anti-VSIG4 treatment resulted in a significant upregulation of cytokines involved in TAM repolarization and T cell activation, and chemokines involved in immune cell recruitment, at levels greater than observed by treatment with anti-PD-1 or a clinical macrophage repolarizing agent (anti-ILT-4). In vivo, tumor growth inhibition is observed in syngeneic mouse models dosed with anti-mouse-VSIG4 alone and in combination with anti-PD-1.ConclusionsTaken together, these data suggest that VSIG4 represents a promising new target capable of stimulating an anti-cancer response via multiple key immune mechanisms.Referencesvan Lookeren Campagne M, Verschoor A. Pathogen clearance and immune adherence “revisited”: immuno-regulatory roles for CRIg. Semin Immunol 2018;37:4–11.Xu S, Sun Z, Li L, Liu J, He J, Song D, Shan G, Liu H, Wu X. Induction of T cells suppression by dendritic cells transfected with VSIG4 recombinant adenovirus. Immunol Lett 2010;128(1):46–50.Liao Y, Guo S, Chen Y, Cao D, Xu H, Yang C, Fei L, Ni B, Ruan Z. VSIG4 expression on macrophages facilitates lung cancer development. Lab Invest 2014;94(7):706–715.Roh J, Jeon Y, Lee A, Lee S, Kim Y, Sung C, Park C, Hong J, Yoon D, Suh C, Huh J, Choi I, Park C. The immune checkpoint molecule V-set Ig domain-containing 4 is an independent prognostic factor for multiple myeloma. Oncotarget 2017;8(35):58122–58132.Xu T, Jiang Y, Yan Y, Wang H, Lu C, Xu H, Li W, Fu D, Lu Y, Chen J. VSIG4 is highly expressed and correlated with poor prognosis of high-grade glioma patients. Am J Transl Res 2015;7(6):1172–1180.Byun J, Jeong D, Choi I, Lee D, Kang M, Jung K, Jeon Y, Kim Y, Jung E, Lee K, Sung M, Kim K. The significance of VSIG4 expression in ovarian cancer. Int J Gynecol Cancer 2017;27(5):872–878.Ethics ApprovalAll legal and ethical requirements were met with regards to the humane treatment of animals described in the study. The animal study was conducted in compliance with CRL IACUC under IACUC No. I033.


2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Damian Clarke ◽  
Corinne Letendre ◽  
Marie-Pier Lecours ◽  
Paul Lemire ◽  
Tristan Galbas ◽  
...  

Group BStreptococcus(GBS) serotype III causes life-threatening infections. Cytokines have emerged as important players for the control of disease, particularly IFN-γ. Although potential sources of this cytokine have been proposed, no specific cell line has ever been described as a leading contributor. In this study, CD4+T cell activation profiles in response to GBS were evaluated throughin vivo,ex vivo,andin vitroapproaches. Total splenocytes readily produce a type 1 proinflammatory response by releasing IFN-γ, TNF-α, and IL-6 and actively recruit T cells via chemokines like CXCL9, CXCL10, and CCL3. Responding CD4+T cells differentiate into Th1 cells producing large amounts of IFN-γ, TNF-α, and IL-2.In vitrostudies using dendritic cell and CD4+T cell cocultures infected with wild-type GBS or a nonencapsulated mutant suggested that GBS capsular polysaccharide, one of the major bacterial virulence factors, differentially modulates surface expression of CD69 and IFN-γproduction. Overall, CD4+T cells are important producers of IFN-γand might thus influence the course of GBS infection through the expression balance of this cytokine.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1836-1836 ◽  
Author(s):  
Marina Bacac ◽  
Pablo Umaña ◽  
Sylvia Herter ◽  
Sara Colombetti ◽  
Johannes Sam ◽  
...  

Abstract Despite the recent advancements in treatment options with the introduction of anti-CD20 monoclonal antibody therapy, approximately 50% of patients with non-Hodgkin's lymphomas (NHL) will not sustain a durable response to standard of care (SOC) treatment. Thus, there remains a continuous need for safer and more effective anti-cancer therapies in this indication. T-cell bispecific antibodies (TCBs) represent a new class of disease targeting agents shown to promote the activation of a patient's own T cells to attack and kill cancer cells. CD20 TCB is a new bispecific antibody with IgG-like pharmacokinetic properties whose unique "2:1" structure leads to increased tumor antigen avidity, T cell activation, and tumor cell killing, as compared to other T cell engaging bispecific antibody molecular formats. The molecule comprises two CD20 binding Fabs (derived from the Type II CD20 IgG1 obinutuzumab), one CD3e binding Fab (fused to one of the CD20 Fabs via a short flexible linker), and an engineered, heterodimeric Fc region with completely abolished binding to FcgRs and C1q. In vitro, CD20 TCB was shown to dose-dependently induce tumor lysis with EC50 values in the range of 0.05 - 3.1 pM. The "2:1"format of CD20 TCB was shown to confer superior potency (up to 10 - 1000x) when compared to CD20 TCBs having the conventional "1:1" IgG-based format (i.e., one binding domain for CD20 and one for CD3). CD20 TCB-mediated tumor lysis resulted in T-cell activation, proliferation and cytokine release with up-regulation of programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) axis upon tumor lysis. CD20 TCB also demonstrated potent ex vivo activity in whole bone marrow aspirate samples of NHL and CLL patients (n=17). Such primary tumor samples preserve the native tumor microenvironment and bear low effector to target cell ratios ranging in this study from 0.02 to 0.8 (average value 0.3). CD20 TCB activity was consistently superior to that of the "1:1" CD20 TCB and demonstrated faster, more profound and more potent B cell depletion with EC50 values ranging from 0.002 to 2.7 nM. In vivo, CD20 TCB displayed potent anti-tumor activity in xenograft models in stem cell humanized mice and induced regression of large, aggressive WSU-DLCL2 lymphoma tumors (0.5 mg/kg, weekly administration). In addition to tumor regression, CD20 TCB treatment led to fast and complete elimination of peripheral blood B cells within 24 h after the first administration (0.05, 0.15 and 0.5 mg/kg, weekly administration) and to a complete elimination of B cells in spleen, bone marrow and lymph nodes after two administrations. B cell depletion was paralleled by transient decrease of T-cell counts in the peripheral blood and by the peak of cytokine release 24 h after the first administration, followed by rapid recovery and return to baseline levels at 72 h post treatment. Tumor growth inhibition mediated by CD20 TCB was accompanied by increase in intra-tumor T-cell infiltration, up-regulation of PD-1 receptor on T cells and PD-L1 in the tumor. Combination studies of CD20 TCB with PD-L1 blocking antibody led to more profound and faster tumor growth inhibition. Taken together, the preclinical data show that CD20 TCB is a novel differentiated CD20-targeting T cell bispecific antibody with promising anti-tumor activity and the ability to modify the tumor microenvironment. CD20 TCB consistently demonstrated superior potency compared to other CD20 TCBs with a conventional "1:1" IgG format. This translated into superior efficacy in vitro, ex-vivo and in vivo, which could not be matched by increasing doses of the "1:1" TCBs. The molecule is now scheduled to start clinical trial by December 2016. Disclosures Bacac: Roche: Employment, Equity Ownership, Patents & Royalties. Umaña:Roche: Employment, Equity Ownership, Patents & Royalties. Herter:Roche: Employment, Patents & Royalties. Colombetti:Roche: Employment. Sam:Roche: Employment. Le Clech:Roche: Employment. Freimoser-Grundschober:Roche: Employment. Richard:Roche: Employment. Nicolini:Roche: Employment. Gerdes:Roche: Employment. Lariviere:Roche: Employment. Neumann:Roche: Employment. Klein:Roche: Employment, Patents & Royalties.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A746-A746
Author(s):  
Kristel Kemper ◽  
Ellis Gielen ◽  
Mischa Houtkamp ◽  
Peter Boross ◽  
Saskia Burm ◽  
...  

BackgroundThe tumor-associated antigen 5T4 is expressed across a wide range of solid cancers. DuoBody-CD3x5T4 is a bispecific antibody (bsAb) that crosslinks CD3 on T cells with 5T4 on tumor cells, thereby inducing T-cell activation and T-cell mediated cytotoxicity in 5T4-expressing tumor cells. Here, we tested the capacity of DuoBody-CD3x5T4 to engage different T-cell subsets in vitro and investigated the mechanism of action (MoA) in vivo by combining preclinical efficacy studies with exploratory pharmacodynamic (PD) biomarker analysesMethodsImmunohistochemistry was performed on patient-derived tumor tissue-microarrays using a commercial 5T4 monoclonal antibody (EPR5529). The capacity of DuoBody-CD3x5T4 to engage naïve and memory T-cell subsets was assessed in co-cultures of T cells and 5T4-positive tumor cells, using T-cell activation and T-cell mediated cytotoxicity as readouts. Anti-tumor activity in vivo as well as peripheral and intratumoral PD biomarkers were investigated in humanized mice bearing 5T4-expressing cell line-derived xenograft (CDX) or patient-derived xenograft (PDX) tumor models.ResultsHigh prevalence of 5T4 expression (in >86% of biopsies) was observed in NSCLC, SCCHN, TNBC, bladder, esophageal, prostate and uterine cancer. In co-cultures of 5T4+ tumor cells and T cells in vitro, DuoBody-CD3x5T4 induced dose-dependent cytotoxicity, associated with T-cell activation, proliferation, and cytokine, perforin and granzyme production. Crosslinking of T cells with 5T4-expressing tumor cells was essential as no cytotoxicity was observed in CRISPR-Cas9-generated 5T4-knockout tumor cells or with control bsAbs targeting only CD3 or 5T4. Importantly, naïve and memory CD4+ or CD8+ T-cell subsets had equal capacity to mediate DuoBody-CD3x5T4-induced cytotoxicity, although naïve T-cell subsets showed slower kinetics. DuoBody-CD3x5T4 (0.5–20 mg/kg) demonstrated anti-tumor activity in 5T4+ breast and prostate cancer CDX and lung cancer PDX models in humanized mice. Treatment with DuoBody-CD3x5T4 was associated with intratumoral and peripheral T-cell activation as well as elevated cytokine levels, including IFNγ, IL-6 and IL-8, in peripheral blood.ConclusionsDuoBody-CD3x5T4 induced T-cell mediated cytotoxicity in 5T4-expressing tumor cells, associated with T-cell activation and cytokine production in vitro. DuoBody-CD3x5T4 efficiently engaged naïve and memory T cells within both CD4+ and CD8+ T-cell populations to induce T-cell mediated cytotoxicity in 5T4+ tumor cells. In humanized CDX and PDX mouse models, DuoBody-CD3x5T4 showed anti-tumor activity, in addition to PD biomarkers associated with T-cell activation in the tumor and periphery. Currently, DuoBody-CD3x5T4 is being investigated in a first-in-human clinical trial for the treatment of solid tumors (NCT04424641), in which exploratory biomarker analyses to study the clinical MoA and PD are included.Ethics ApprovalThe CDX animal experiments performed are in compliance with the Dutch animal protection law (WoD) translated from the directives (2010/63/EU) and are approved by the Ethical committee of Utrecht. For the PDX models, all patients had given written informed consent, and the animal experiments were carried out in accordance with the German Animal Protection Law (LaGeSoBerlin, A0452/08). The studies were approved by the local Institutional Review Board of Charite University Medicine, Germany.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lauric Haber ◽  
Kara Olson ◽  
Marcus P. Kelly ◽  
Alison Crawford ◽  
David J. DiLillo ◽  
...  

AbstractT-cell-redirecting bispecific antibodies have emerged as a new class of therapeutic agents designed to simultaneously bind to T cells via CD3 and to tumor cells via tumor-cell-specific antigens (TSA), inducing T-cell-mediated killing of tumor cells. The promising preclinical and clinical efficacy of TSAxCD3 antibodies is often accompanied by toxicities such as cytokine release syndrome due to T-cell activation. How the efficacy and toxicity profile of the TSAxCD3 bispecific antibodies depends on the binding affinity to CD3 remains unclear. Here, we evaluate bispecific antibodies that were engineered to have a range of CD3 affinities, while retaining the same binding affinity for the selected tumor antigen. These agents were tested for their ability to kill tumor cells in vitro, and their biodistribution, serum half-life, and anti-tumor activity in vivo. Remarkably, by altering the binding affinity for CD3 alone, we can generate bispecific antibodies that maintain potent killing of TSA + tumor cells but display differential patterns of cytokine release, pharmacokinetics, and biodistribution. Therefore, tuning CD3 affinity is a promising method to improve the therapeutic index of T-cell-engaging bispecific antibodies.


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