Seven years ago, the US Food and Drug Administration (FDA) approved the first product in a new class of biologics: antibody–drug conjugates (ADCs). The idea for these products already had been hatched a decade earlier when the promising field of antibody research — touting such molecules as “magic bullets” — had faltered, specifically against oncology-related indications. The early crop of anticancer monoclonal antibodies (MAbs) proved to have only limited efficacy, and interest in developing antibodies as therapeutic agents against cancer…