What is an Antibody-Drug Conjugate (ADC)?

An Antibody-Drug Conjugate (ADC) combines the targeting specificity of monoclonal antibodies with the cytotoxic potency of small molecule drugs. Components include: the antibody (targets tumor-specific antigen), the linker (connects drug to antibody, cleavable or non-cleavable), and the payload (highly potent cytotoxic agent like auristatins, maytansinoids, or camptothecins). Mechanism: ADC binds to target antigen on cancer cells, is internalized via endocytosis, and releases the cytotoxic drug inside the cell. This targeted delivery reduces systemic toxicity compared to conventional chemotherapy. Key parameters include Drug-to-Antibody Ratio (DAR, typically 2-4), linker stability, and payload potency. FDA-approved ADCs include Kadcyla (breast cancer), Adcetris (lymphoma), and Enhertu (breast cancer).