Synthesis and Characterization of Cetuximab-Docetaxel and Panitumumab-Docetaxel Antibody-Drug Conjugates for EGFR-Overexpressing Cancer Therapy

The safety and efficacy of anticancer antibody-drug conjugates (ADC) depend on the selection of tumor-targeting monoclonal antibody (mAb), linker, and drug, as well as their specific chemical arrangement and linkage chemistry. In this study, we used a bifunctional linker to conjugate docetaxel (DX) to cetuximab (CET) or panitumumab (PAN). The resulting double-drug ADCs were investigated for their in vitro EGFR-specific cytotoxicity and in vivo anticancer activity. Reaction conditions, such as reducing agent, time, temperature, and alkylation buffer, were optimized to yield potent and stable ADCs with consistent batch-to-batch DARs. ADCs were synthesized with DARs from 0.4 to 3.0, and all retained their EGFR affinity and specificity after modification. ADCs were sensitive to cell surface EGFR expression, demonstrating more cytotoxicity in high EGFR-expressing A431 and MDA-MB-231 cells lines compared to low EGFR-expressing U87MG cells. ADCs were equipotent to DX in high EGFR-expressing A431 cells and signif...