The owner of a patent on a brand-name drug sues a competitor for infringing the patent. The parties settle. But the infringer doesn't pay. The patent-owner does. Why? In return for the competitor's agreement not to compete during the rest of the patent's term.

Four of our 13 courts of appeals held that such a "reverse

K-Dur treats low potassium. We think.

Since 2003, the Federal Trade Commission has fought a losing battle to halt bargains in which a brand-name drug-maker pays a generic competitor to put off entering the market. Pacts like that, the agency urged, result in "reverse payments", which compensate a patent infringer not to do stuff that might infringe the patent. Such arrangements violate antitrust law