At its heart, a patent grants the right to stop another person from doing whatever falls within the scope of the patent’s claims. A patent is not a right to practice what is included in the patent, or a government stamp of approval on everything within the scope of its claims. If so, then perhaps the U.S. Patent and Trademark Office (USPTO) or a court involved in patent litigation would take the role of the U.S. Food and Drug Administration (FDA) in determining whether, for example, a patent claiming a method of treatment is limited to safe and effective use of a drug. The Federal Circuit recently clarified the USPTO’s role in United Therapeutics Corp. v. Liquidia Techs., Inc., a decision of interest not just to patent practitioners but to those involved with clinical trials and drug development.

One of United Therapeutics’ patents at issue claimed a method of “treating pulmonary hypertension” with treprostinil. The parties’ experts agreed that a subtype of pulmonary hypertension (“Group 2”) would not be benefited by administration of treprostinil, and a clinical trial of this subtype had failed due to increased mortality. Liquidia argued that the District Court had erred in not considering safety and efficacy when construing the claim element, “treating pulmonary hypertension,” even though the claim itself said nothing about safety. The court stated that questions of safety and efficacy in patent law have long fallen under the purview of the FDA, and that the requirements under the law for obtaining a patent are different from the requirements for obtaining government approval to market a particular drug. As such, the court declined to limit the scope of the claims to a safe use absent any safety-related claim limitation.

Related to its claim scope argument, Liquidia asserted that the claims were invalid for lack of enablement and written description because the patent provided no guidance or examples of treating Group 2 patients. The court concluded, however, that the claims were enabled and adequately supported, pointing out that even if a clinical study had failed due to increased mortality, the study had still shown an improvement in hemodynamics in the Group 2 patients. The court indicated that the safety concerns pointed to by Liquidia were matters for the FDA and medical practitioners, and not an issue for the court, because safety and efficacy were not recited in the claims.

In sum, the Federal Circuit has confirmed that patents may be granted on claims encompassing unsafe uses of a drug. From those laboring under the misconception that a patent grant somehow equates to a governmental stamp-of-approval to practice the claimed subject matter, this may seem strange. However, this decision is consistent with the role of the patent system, which does not grant any rights to practice an invention, but rather grants rights to stop others from doing so. United Therapeutics v. Liquidia underscores that the patent system’s role is generally detached from evaluating safety or efficacy, and that it is the role of other governmental agencies—such as the FDA—to make evaluations of public safety and to grant approvals based on those evaluations.