Protease-activation using anti-idiotypic masks enables tumor specificity of a folate receptor 1-T cell bispecific antibody

• Published in: Nature communications Vol. 11; no. 1; pp. 3196 - 14
• Main Authors: Geiger, Martina, Stubenrauch, Kay-Gunnar, Sam, Johannes, Richter, Wolfgang F., Jordan, Gregor, Eckmann, Jan, Hage, Carina, Nicolini, Valeria, Freimoser-Grundschober, Anne, Ritter, Mirko, Lauer, Matthias E., Stahlberg, Henning, Ringler, Philippe, Patel, Jigar, Sullivan, Eric, Grau-Richards, Sandra, Endres, Stefan, Kobold, Sebastian, Umaña, Pablo, Brünker, Peter, Klein, Christian
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.06.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 13; 13/1; 13/21; 13/31; 13/51; 631/67/1059/153; 631/67/1059/2325; 631/67/1059/602; 64; 64/60; Animals; Antibodies; Antibodies, Bispecific - chemistry; Antibodies, Bispecific - immunology; Antibodies, Bispecific - metabolism; Antibodies, Bispecific - therapeutic use; Anticancer properties; Antigens; Antitumor activity; Biocompatibility; Bispecific antibodies; CD3 antigen; CD3 Complex - immunology; Cell Line, Tumor; Cleavage; Cloning; Crosslinking; Crystal structure; Fab; Folate Receptor 1 - immunology; Folic acid; GPI-Linked Proteins - immunology; Humanities and Social Sciences; Humans; Immunotherapy; Lymphocyte Activation - drug effects; Lymphocytes; Lymphocytes T; Masking; Masks; Medical research; Mesothelin; Mice; Molecular Targeted Therapy; multidisciplinary; Ovarian cancer; Peptide Hydrolases - metabolism; Protease; Proteinase; R&D; Receptors; Research & development; Science; Science (multidisciplinary); Selectivity; T-Lymphocytes - immunology; Toxicity; Tumors; Vitamin B; Xenograft Model Antitumor Assays
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-16838-w

T-cell bispecific antibodies (TCBs) crosslink tumor and T-cells to induce tumor cell killing. While TCBs are very potent, on-target off-tumor toxicity remains a challenge when selecting targets. Here, we describe a protease-activated anti-folate receptor 1 TCB (Prot-FOLR1-TCB) equipped with an anti-idiotypic anti-CD3 mask connected to the anti-CD3 Fab through a tumor protease-cleavable linker. The potency of this Prot- FOLR1-TCB is recovered following protease-cleavage of the linker releasing the anti-idiotypic anti-CD3 scFv. In vivo, the Prot-FOLR1-TCB mediates antitumor efficacy comparable to the parental FOLR1-TCB whereas a noncleavable control Prot-FOLR1-TCB is inactive. In contrast, killing of bronchial epithelial and renal cortical cells with low FOLR1 expression is prevented compared to the parental FOLR1-TCB. The findings are confirmed for mesothelin as alternative tumor antigen. Thus, masking the anti-CD3 Fab fragment with an anti-idiotypic mask and cleavage of the mask by tumor-specific proteases can be applied to enhance specificity and safety of TCBs. The clinical application of T cell bispecific antibodies (TCBs) is often limited by the lack of tumour-specific antigens. In this study, the authors present a strategy to increase TCB tumour-selectivity by adding an anti-CD3 moiety that can be specifically activated by tumor specific proteases in the tumor microenvironment.