Fig. 1 |. Modular components of ADCs.

a | Schematic representation of an antibody–drug conjugate (ADC), with the antibody in green, linker in blue and payload in yellow. This representative ADC has a drug-to-antibody ratio of 4. b | Illustration of the modular nature of ADCs, whereby an antibody with a given target can be attached to a payload via a cleavable or non-cleavable linker. Most approved ADCs utilize an immunoglobulin G1 (IgG1) backbone, although other antibody isotypes can be used to exploit different physiological attributes (such as serum half-life, complement component C1q-binding capacity and avidity for Fcγ receptors). Representative and commonly used examples of linkers and payloads are depicted, and their key properties are noted. The choice of linker and payload can determine the safety and efficacy of the ADC in different oncology indications. *Non-cleavable maleimidocaproyl (MC) and maleimidomethyl cyclohexane-1-carboxylate (MCC) linkers are often used with monomethyl auristatin F and emtansine payloads, respectively; MC and MCC linkers can be cleavable when conjugated to certain other payloads.