United Therapeutics, in 2020, was granted a patent on the delivery method used in Tyvaso (10,716,793, the ‘793 patent) as well as the creation method of the medication formula (9,593,066, ‘066 patent). Liquidia has been preparing for its generic drug to get FDA approval—which United Therapeutics believed there was patent infringement the drug. Liquidia argued that their activity was non-infringing because United Therapeutics’ patents were invalid and should not have been issued in the first place.
The lawsuit was divided into two different segments. One part of the case took place in federal court, while the other took place in front of the United States Patent and Trademark Office’s Patent Trial and Appeal Board (PTAB). United Therapeutics alleged patent infringement of the ‘793 and ‘066 patents by Liquidia. Thus, the burden of proof shifted to Liquidia to prove that they were not infringing. In response, the company asked the PTAB for an inter partes review, which is used to determine the validity of all parts of patents, on both of United Therapeutics’ asserted patents.
Throughout the course of the PTAB investigation, the panel found that all the claims in dispute within the ‘793 patent were invalid. Liquidia saw this as a victory, while United Therapeutics appealed the decision. Once again, upon second review, the PTAB ruled that all claims from the ‘793 patent that were supposedly infringed by Liquidia were invalid. As argued by Liquidia, and found by the PTAB, the claims were invalid because they lacked the necessary written description and enablement requirements that valid patents demand. As of April 2023, United Therapeutics has appealed this decision.
The issue found with ‘793’s description was that it was considered unsafe. The first claim from ‘793 reads: “A method of treating pulmonary hypertension comprising administering by inhalation to a human suffering from pulmonary hypertension a therapeutically effective single event dose of a formulation comprising Treprostinil.” Liquidia argued that any person of ordinary skill in the art (POSITA) would know that pulmonary hypertension has five different presentations of symptoms and causes. A POSITA would also know that it would be unsafe to treat someone who has Group 2—pulmonary venous hypertension—with Treprostinil, since it would lower the blood pressure of a patient uniquely struggling with low blood pressure. Due to the lack of clarity in the description, the patent claims to treat “pulmonary hypertension” generally, which could be potentially deadly to consumers. Liquidia further argued that because any changes in blood pressure caused by the Treprostinil would help Group 2 patients, the full scope of the claimed invention was not enabled (i.e., “a therapeutically effective” dose).
While the PTAB investigations and decisions were being made, United Therapeutics and Liquidia were seeing each other in district court. These proceedings happened in parallel with the PTAB, with the district court assuming—unless told otherwise—that the patents were valid. The district court found that Liquidia was, in fact, infringing on United Therapeutics’ patents: claims 1, 4, and 6-8 of the ‘793 patent. In court, Liquidia argued that claims 1-3 of the ‘066 patent were invalid, which the court agreed. Further, the court found that Liquidia’s medication would not infringe on the valid claims—6 through 9—of the ‘066 patent. This ruling was appealed by both parties—United Therapeutics, believing all claims of the ‘066 patent were patentable, and Liquidia, believing the claims within the ‘793 patent were also invalid. Upon appeal, the Federal Circuit affirmed the district court’s decision.
The Federal Circuit was not swayed by Liquidia’s arguments, and continued to uphold the validity (and therefore, infringement) of the claims in the ‘793 patent. The opinion stated that the question of “safety and efficacy of treating Group 2 PH patients is not before us” because, traditionally, all “[q]uestions of safety and efficacy in patent law have long fallen under the purview of the FDA.”
Until the final decision for the PTAB appeal has been reached, Liquidia will be prevented from advertising, selling, or attempting FDA approval for their generic medication until United Therapeutics’ patent expires in 2027.
In September of 2023, United Therapeutic filed another patent infringement action against Liquidia alleging that Liquidia infringed upon the ‘793 patent as Liquidia had submitted an amendment to the FDA seeking approval to engage in manufacturing of Yutrepia prior to the expiration of United Therapeutic’s ‘793 patent. No further action has been taken in this case; however, it shows that the fight over the ‘793 patent is far from over.
Patents afford businesses a monopoly on certain methods, inventions, and their licenses for the entire length of their validity. Patent infringers can take business away from rights-owners and can require lengthy, expensive trials to remedy the issue—even challenging the validity of the patent itself. All companies, no matter size or product, run the risk of having an intellectual property liability. Being prepared to assert one’s rights or defend against erroneous attacks allows businesses to protect the goods they have spent so much time, money, and passion to develop. Insuring your intellectual property against infringement is something the experts here at IPISC have been doing for over thirty years! If you are interested in intellectual property coverage against future infringers and are interested in learning more about what we can offer, explore our website, and connect with us.
