Observers worry that generic patent challenges are on the rise and reduce the effective market life of drugs. A related concern is that challenges disproportionately target high-sales drugs, reducing market life for these “blockbusters.”

Predation occurs when a firm offers consumers favorable deals, usually in the short run, that get rid of competition and thereby harm consumers in the long run. Modern economic theory has shown how commitment or collective-action problems among consumers can lead to such paradoxical effects. But...