Material Event - Form 8-K

On February 26, 2024, United Therapeutics Corporation (the Company) filed a motion in the U.S. District Court for the District of Delaware for a preliminary injunction in its previously-disclosed patent litigation with Liquidia Technologies, Inc. (Liquidia) related to Liquidia's efforts to seek approval by the U.S. Food and Drug Administration (FDA) for a pulmonary hypertension associated with interstitial lung disease (PH-ILD) indication for its inhaled treprostinil product. Liquidia's investigational product is currently tentatively approved by the FDA for the treatment of pulmonary arterial hypertension (PAH) but not PH-ILD. In this litigation, the Company alleges that Liquidia's product for use in PH-ILD infringes the Company's U.S. Patent No. 11,826,327 (the '327 patent), which expires in 2042. The '327 patent generally covers improving exercise capacity in patients suffering from PH-ILD by administering treprostinil by inhalation. In its preliminary injunction motion, the Company asked the district court to enjoin Liquidia from marketing its product for PH-ILD until the court can adjudicate the Company's infringement claims.

Separately, as previously disclosed, the Company has initiated litigation in the U.S. District Court for the District of Columbia against the FDA in another case regarding the FDA's review of Liquidia's efforts to obtain a PH-ILD indication for its inhaled treprostinil product. Liquidia submitted an amendment to the pending new drug application (NDA) for its product to pursue approval for a PH-ILD indication. The suit alleges that FDA rules, precedents, and procedures require that such a new indication be pursued in a new NDA rather than as an amendment to a pending NDA. Thus, the Company has asked FDA to require Liquidia to submit a new NDA if it wishes to further pursue approval for a PH-ILD indication. The Company believes that if Liquidia is required to submit a new NDA, the Company would be entitled to a 30-month stay of any PH-ILD approval for Liquidia's product as a result of the '327 patent litigation.

Together, these two litigation matters respond to Liquidia's efforts to add PH-ILD to its unapproved product label, in addition to an indication for the treatment of PAH. The NDA for Liquidia's product relies on the clinical data underlying the NDA for the Company's product, Tyvaso^® (treprostinil) Inhalation Solution, which is FDA-approved for the treatment of both PAH and PH-ILD. The PH-ILD indication was added to the label for nebulized Tyvaso in 2021, following the first-ever successful pivotal clinical trial of a therapy for PH-ILD. If either a preliminary injunction or a 30-month stay is granted, then Liquidia's product would be precluded from being marketed for PH-ILD while the underlying '327 patent litigation proceeds.

For more details concerning the Company's litigation matters regarding Liquidia, please see Note 14 - Litigation to the Company's Annual Report on Form 10-K filed on February 21, 2024.

TYVASO is a registered trademark of United Therapeutics Corporation.