Last January, in MedImmune Inc. v. Genentech Inc., 127 S. Ct. 764 (2007), the U.S. Supreme Court held that a patent licensee in good standing may sue for a declaratory judgment that the licensed patent is invalid, unenforceable or not infringed. That ruling overturned settled U.S. Court of Appeals for the Federal Circuit precedent prohibiting licensees who are current in their obligation to pay royalties from mounting challenges to licensed patents.

In reaching that result, the Court authored a lengthy footnote (No. 11) discussing the test used by the Federal Circuit to determine when a party threatened with a claim of patent infringement may sue for declaratory judgment. Under that test, a declaratory judgment plaintiff must show that it has a “reasonable apprehension” that “it will face an infringement suit.” This rule does much to place the keys to the courthouse in the hands of the patent holder, who can make it difficult or impossible to trigger declaratory judgment jurisdiction by disclaiming any intent immediately to sue for infringement.