The U.S. Supreme Court case MedImmune, Inc. v. Genentech, Inc., et al., 2006 revolved around patent disputes and the right to challenge a patent's validity without breaching an existing licensing agreement. MedImmune had licensed a patent from Genentech but later sought to challenge its validity in court while continuing to pay royalties under protest, fearing that stopping payments would result in severe penalties for breach of contract and potential infringement charges if they lost the suit. The central question was whether there existed an actual controversy allowing federal courts jurisdiction over such cases even when the plaintiff-licensee is not refusing compliance with the contract (i.e., continues paying royalties). The Supreme Court ruled in favor of MedImmune stating that Article III’s “case or controversy” requirement does not mandate a licensee to risk liability before challenging a license agreement's enforceability.

The dissenting opinion in the MedImmune, Inc. v. Genentech, Inc., case argued that a licensee should not be allowed to challenge the validity of a patent while continuing to enjoy the benefits of the license agreement. The dissenters believed that by entering into such an agreement and making royalty payments under it, MedImmune had acknowledged Genentech's patent rights and thus could not now dispute them without first breaching or terminating its contract with Genentech. They also expressed concern about potential negative impacts on contractual relationships if parties were permitted to challenge agreements they voluntarily entered into while still reaping their benefits.