Characterization of TROP-2 bispecific T cell engagers for immunotherapy of triple negative breast and bladder cancer

Sep 22, 2026

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T cell-based immunotherapy offers expanded options, yet limited clinical benefit persists in triple-negative breast cancer (TNBC) and bladder cancer. The study reports generation and characterization of a panel of TROP-2×CD3 bispecific antibodies combining clinically validated TROP-2 binders with CD3 binders of distinct affinities. These constructs trigger robust T cell activation, cytokine secretion and sustained expansion, producing potent cytotoxicity against TNBC and bladder cancer cells across high and low TROP-2 expression. Enhanced tumor selectivity with low-affinity CD3 improves discrimination between very low and high antigen-expressing cells while reducing cytokine release without compromising antitumor efficacy, supporting further development for solid tumors with heterogeneous TROP-2 levels.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages12

Reading Time30 min

AccessFree to download

Introduction

Immunotherapy and T cell-mobilizing strategies

TROP-2 as a therapeutic target

Study construction of TROP-2×CD3 bispecific antibodies

TYPE Original Research PUBLISHED 12 March 2026 DOI 10.3389/fimmu.2026.1794705 OPEN ACCESS EDITED BY Hiroto Katoh, National Cancer Center Japan, Japan REVIEWED BY Chalermchai Somboonpatarakun, Mahidol University, Thailand Shihao Chen, QLSF Biotherapeutics, Inc, United States *CORRESPONDENCE Ilona Hagelstein [Ilona.Hagelstein@med.uni-tuebingen.de](Ilona.Hagelstein@med.uni-tuebingen.de) RECEIVED 23 January 2026 REVISED 23 February 2026 ACCEPTED 25 February 2026 PUBLISHED 12 March 2026 CITATION A´vila-Nieto C, Jung G, Salih HR and Hagelstein I (2026) Characterization of TROP-2 bispeciﬁc T cell engagers for immunotherapy of triple negative breast and bladder cancer. Front. Immunol. 17:1794705 . doi: 10.3389/fimmu.2026.1794705 COPYRIGHT © 2026 A´vila-Nieto, Jung, Salih and Hagelstein. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Characterization of TROP-2 bispeciﬁc T cell engagers for immunotherapy of triple negative breast and bladder cancer Carlos A´vila-Nieto 1,2,3, Gundram Jung3, Helmut R. Salih 1,2,3 and Ilona Hagelstein 1,2,3* 1German Cancer Consortium (DKTK), Partner Site Tuebingen, a Partnership Between German Cancer Research Center (DKFZ) and University Hospital Tübingen, Tübingen, Germany, 2Clinical Collaboration Unit Translational Immunology, Department of Internal Medicine, University Hospital Tübingen, Tübingen, Germany, 3Cluster of Excellence iFIT (EXC 2180) “Image-Guided and Functionally Instructed Tumor Therapies”, Eberhard Karls University of Tübingen, Tübingen, Germany T cell-based immunotherapy has markedly expanded the therapeutic options in numerous cancers. However, these approaches still achieve only limited clinical beneﬁt in triple negative breast cancer (TNBC) and bladder cancer. Although immune checkpoint inhibitors improve outcomes for a subset of patients, no T cell-redirecting therapies such as CAR-T cells or bispeciﬁc antibodies (bsAbs) have been approved for either indication. Trophoblast cell surface antigen 2 (TROP-2) is highly expressed across several epithelial cancers including TNBC and bladder cancer, but has been primarily exploited as a target for antibody drug conjugates (ADCs) with limited exploration in T cell-engaging constructs. Here, we report on the generation and characterization of a panel of TROP-2×CD3 bsAbs containing clinically validated TROP-2 binders and CD3 binders with distinct afﬁnities. All bsAbs induced robust T cell activation, cytokine secretion and sustained T cell expansion, resulting in potent T cell-mediated cytotoxicity against TNBC and bladder cancer cells with either high or low levels of TROP-2 expression. Notably, combining a TROP-2 binder with enhanced tumor selectivity and a low-afﬁnity CD3 binder increased discrimination between high and very low TROP-2-expressing cells while (reducing cytokine release without compromising anti-tumor efﬁcacy. Thus, TROP-2-directed bsAbs can achieve effective tumor cell killing without over dependence on antigen density, in contrast to ADC-based approaches. Our results support further development of TROP-2×CD3 bsAbs as immunotherapy for solid tumors with heterogeneous or low TROP-2 expression. KEYWORDS immunotherapy, triple negative breast cancer, bladder cancer, TROP-2, CD3, bispeciﬁc antibody 1 Introduction Over the recent years, immunotherapy has revolutionized oncological treatment. Among the most impactful developments are T cell-mobilizing strategies, which have demonstrated meaningful survival beneﬁts across multiple malignancies (1–3) . These include immune checkp

FAQs

Why focus on TROP-2×CD3 bispecific antibodies for TNBC and bladder cancer?

TROP-2 is highly expressed across epithelial cancers, including TNBC and bladder cancer. While TROP-2 has been used mainly in antibody drug conjugates, its application in T cell-engaging bispecific constructs is less explored, motivating this work.

What do the TROP-2×CD3 bispecific antibodies induce in T cells?

The panel of bispecific antibodies induces robust T cell activation, cytokine secretion and sustained T cell expansion. This translates into potent T cell-mediated cytotoxicity against both TNBC and bladder cancer cells.

How does combining tumor selectivity with a low-affinity CD3 binder affect performance?

Pairing a TROP-2 binder with enhanced tumor selectivity and a low-affinity CD3 binder increases discrimination between high and very low TROP-2-expressing cells. It also reduces cytokine release without compromising antitumor efficacy.

Sep 22, 2026

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