The regulatory pathway to approve ‘biosimilar’ competitors was signed into U.S. law in 2010, but savings have been slow to materialize until recently. Earlybiosimilars have been few in number and generated limited savings compared to expectations. Slower uptake and muted savings raise fundamental questionsaround defining the success of biosimilars for all stakeholders, and particularly patients. By contrast, recent events suggest an inflection has occurred and eventsexpected in the next few years potentially offer to bring further significant shifts.