Monoclonal antibody (MAb) based therapies have achieved considerable success in oncology, primarily when used in combination with cytotoxic drugs. Antibody drug conjugates (ADCs) are a class of therapeutics that harness the antigen-selectivity of MAbs to deliver highly potent cytotoxic drugs to antigen-expressing tumor cells. The use of MAb directed delivery can confer a therapeutic index to highly potent cytotoxic drugs, increasing both the efficacy and safety of therapy. Although simple in concept, to achieve the design goal of improved therapeutic efficacy and reduced toxicity, each of the components of an ADC; the MAb, linker and drug need to considered in the context of the targeted antigen, the selectivity of antigen expression and the biology of the tumor type on which the target antigen is expressed. The characteristics of targets, MAbs, linkers and drugs being used in ADC design are discussed.
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