The US Supreme Court issued an opinion today in Medimmune, Inc. v. Genetech, Inc., et al. that held (8 to 1) that, under the facts of that case,? a licensee was not required terminate its existing license or be in breach prior to seeking a declaratory judgment that the licensed patent was invalid, unenforceable, or not infringed.

This was one of the long-standing issues confronting a patent licensee, and for licensees having similar fact patterns this question is resolved in their favors. Namely, you can keep your license and challenge the underlying patent.

This opinion of the court does not say that the parties could not have agreed to limits of the licensee’s ability to challenge the validity/enforceability/infringement of the patent, just that they could not find any basis to say that the licensee was in fact constrained based upon the particular license agreement.

In other words, it is not inherently the case that signing up for a license automatically prevents challenges to the licensed technology.