Antibody-drug conjugate cytotoxic payload (ADC payload)

Antibody-drug conjugate (ADC) cytotoxic payloads are highly potent small molecule drugs chemically linked to monoclonal antibodies to provide targeted delivery to specific cell populations, primarily in oncology (Nature Reviews Drug Discovery, 2022). These payloads are typically several orders of magnitude more toxic than conventional chemotherapy agents, necessitating their delivery via a targeted vehicle to minimize systemic exposure (Journal of Hematology & Oncology, 2021). Upon binding of the antibody to a cell-surface antigen and subsequent internalization, the payload is released—often through lysosomal degradation or linker cleavage—where it then interacts with its intracellular target, such as tubulin or DNA (ACS Medicinal Chemistry Letters, 2020). The choice of payload is critical to the ADC's efficacy and safety profile, with common classes including auristatins, maytansinoids, and camptothecin derivatives (PubMed, PMID: 33097403). While highly effective at killing tumor cells, these payloads also present significant challenges, including potential off-target toxicity if the drug is released into systemic circulation or if it diffuses into neighboring healthy cells via the bystander effect (Clinical Cancer Research, 2019).

Other names

Cytotoxic warheadADC effectorCytotoxinSmall molecule payload

ADC cytotoxic payloads function by disrupting essential cellular processes once released into the cytoplasm or nucleus of a target cell. Microtubule-disrupting agents, such as auristatins and maytansinoids, inhibit tubulin polymerization, leading to G2/M phase cell cycle arrest and apoptosis (Nature Reviews Clinical Oncology, 2020). DNA-damaging agents, including calicheamicins and pyrrolobenzodiazepines (PBDs), cause double-strand breaks or DNA alkylation, resulting in genomic instability (Antibodies, 2019). More recently, Topoisomerase I inhibitors like SN-38 and DXd have been utilized to induce DNA damage during replication, particularly effective in high-antigen-expressing tumors (Cancer Science, 2022).