The Market-Expanding Role of Regulatory Approval in Medicine

Abstract Regulatory review is often seen as a barrier to innovation, increasing costs and delaying new medicines. Yet approval may also expand markets by certifying quality and reducing uncertainty. We test this by studying FDA approval for follow-on indications—uses that physicians could already prescribe “offlabel” — and find approval raises use in newly approved diseases by 25 percent within a year, with larger increases in smaller off-label markets. Subsequent approvals in the same disease yield smaller gains. Our results suggest regulatory approval of medicines expands market size by increasing demand, rather than easing insurer-imposed restrictions, revealing limits to marketbased learning.