Menu
October 15, 2024
On Monday, October 7, 2024, the U.S. Supreme Court (“SCOTUS”) denied United Therapeutics Corporation (“UTC”) petition for certiorari clearing the way for Liquidia Corporation (“Liquidia”) to launch its Yutrpia® drug product. This decision marks the end of the patent litigation battle between the two pharmaceutical companies, representing a setback for UTC. However, Liquidia must now wait until UTC’s newly granted FDA exclusivity period expires on May 23, 2025 before launching Yutrpia®.
This litigation highlights the contrasting pathways and outcomes when challenging patent validity. In district court cases, even with a finding of invalidity, the patent claims remain in effect until all appeals are resolved. In contrast, at the USPTO’s Patent Trial and Appeal Board (“PTAB”), a finding of unpatentability requires the Director to issue a formal certificate of cancellation, which happens only after all appeals are exhausted, and the timing of the certificate issuance remains uncertain. When timing is critical in the race to final judgment between concurrent PTAB and district court proceedings, parties must consider the timing of the PTAB’s issuance of a certificate of cancellation when formulating their strategy.
UTC’s new drug application (“NDA”) for Tyvaso®, an inhalation solution of treprostinil used for the treatment of pulmonary hypertension, was approved in 2009.
In January 2020, Liquidia filed a Section 505(b)(2) NDA with the Food and Drug Administration (“FDA”) for Yutrepia®, an inhalation powder of treprostinil indicated to treat adults with pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease. 1
On May 23, 2022, the FDA approved UTC’s inhalation powder for treprostinil, called Tyvaso DPI®. The FDA also recently granted three years of regulatory exclusivity to UTC for chronic use of “essentially any dry-powder formulation of treprostinil” in the approved indications for its new dosage form, set to expire on May 23, 2025. 2
U.S. Patent No. 10,716,793 (“the ’793 patent”) was listed in FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations (“Orange Book”) for Tyvaso. 3 After receiving a notice letter from Liquidia indicating that Liquidia intends to launch before the expiration of the ’793 patent, UTC sued Liquidia in the District of Delaware for infringement of the ’793 patent.
Liquidia alleged the ’793 patent was invalid as being obvious (under 35 U.S.C. § 103), anticipated (under 35 U.S.C. § 102), and for lack of written description and enablement (under 35 U.S.C. § 112). Prior to trial, Liquidia dropped the prior art challenges and pursued them in an inter partes review at the PTAB.
On July 19, 2022, the PTAB held the claims of the ’793 patent were invalid as being obvious. 4 A little over a month later, on September 9, 2022, the District of Delaware held that the ’793 patent was infringed and not invalid under written description and enablement. 5
The Federal Circuit affirmed the validity ruling (under § 112) from the District of Delaware on July 24, 20236, and then affirmed the invalidity ruling (under § 103) from the PTAB on December 20, 20237. Based on the two federal circuit decisions, the ’793 patent claims were invalid as being obvious. Six days after the Federal Circuit’s holding of invalidity, Liquidia filed a Rule 60(b) motion with the District of Delaware to lift the injunction as there’s been a legal change that makes the judgment no longer applicable, and on March 28, 2024, the court granted the motion and vacated the injunction. 8
UTC appealed the District of Delaware’s decision to vacate the injunction and oral arguments at the Federal Circuit were held on September 3, 2024.
UTC argued the district court ignored the statutory requirements for an injunction under 35 U.S.C. § 271(e)(4)(D) that when a patent is infringed, the court shall order a permanent injunction until the patent expires, and since the Federal Circuit held that the patent was infringed, the injunction should not be lifted.
UTC also contended that the PTAB’s ruling that the ’793 patent is “unpatentable” differs significantly from a district court’s invalidity determination. UTC argued that, unlike a district court’s invalidity decision, which takes immediate effect, the PTAB’s finding of unpatentability requires further due process, including formal cancellation of the patent and issuance of a certificate to the district court before any injunction can be lifted. Additionally, patent cancellation cannot occur until all appeals are resolved, and a certiorari petition was pending before SCOTUS, filed on June 10, 2024. 9
UTC further argued that the District of Delaware improperly relied on issue preclusion, as the invalidity issues before the district court and the PTAB were not identical. Specifically, the district court addressed invalidity under §112, while the PTAB considered invalidity under §§102/103.
Liquidia argued that the ’793 patent is both invalid and unenforceable, and therefore cannot justify upholding the injunction. They claimed that the Federal Circuit had already issued its mandate to the PTAB, which is now merely performing the “non-discretionary formality” of canceling the patent—a step that does not impact the binding effect of the decision. Liquidia further contended that they would face harm if the FDA granted final approval to any other application based on UTC’s drug product, as this would delay their own product launch while awaiting the patent’s formal cancellation by the FDA.
Additionally, Liquidia argued that the District of Delaware correctly applied issue preclusion, asserting that the Federal Circuit’s affirmation of invalidity—whether by a district court or the PTAB—has collateral estoppel effect on all pending actions. They noted that the district court’s case remains open, as substantive issues still need to be resolved following the issuance of the mandate. Liquidia also contended that maintaining an injunction based on an invalid patent is inequitable and contrary to the public interest, emphasizing that UTC’s pending certiorari petition does not alter the fact that the patent has been ruled invalid.
During oral arguments before the Federal Circuit, UTC conceded that if SCOTUS denied the certiorari petition and the PTAB subsequently canceled the patent, the pending Federal Circuit appeal would become moot.
On October 7, 2024, SCOTUS denied the cert petition. 10 As a result, Liquidia will notify the PTAB, the Director will cancel the patent, and the Federal Circuit appeal will be rendered moot.
Through all their efforts in invalidating UTC’s ’793 patent, Liquidia must still wait for final FDA approval before launching Yutrepia® after UTC’s exclusivity period ends on May 23, 2025. 11