In Vivo Biorthogonal Antibody Click for Dual Targeting and Augmented Efficacy in Cancer Treatment

Abstract

Antibody-drug conjugates (ADCs) have emerged as promising therapeutics for cancer treatment; however, their effectiveness has been limited by single antigen targeting, potentially leading to resistance mechanisms triggered by tumor compensatory pathways or reduced expression of the target protein. Here, we present antibody-ADC click, an approach that harnesses bioorthogonal click chemistry for in vivo dual targeting of ADCs, irrespective of the tumor's expression of the ADC-targeting antigen. We conjugated the bioorthogonal click moieties tetrazine (Tz) and trans-cyclooctene (TCO) to both antibodies and ADCs. Through in vivo clicking of antibody-TCO with antibody-Tz, we achieved sequential dual-receptor targeting in tumors. We show that the clicked antibody therapy outperformed conventional ADC monotherapy in preclinical models mimicking ADC-eligible, ADC-resistant, and ADC-ineligible tumors. Antibody-ADC click allows reversal of drug resistance through multi-antigen targeting and enhanced ADC accumulation within tumors. Antibody-ADC click enables in vivo multi-targeting without extensive bioengineering, sustains tumor treatment, and enhances antibody-mediated cytotoxicity.