According to Liquidia Corporation, an inter partes review by the US Patent Trial and Appeal Board (PTAB) regarding US Patent No. 9,604,901, which is listed in the Orange Book as one of 7 patents covering United Therapeutics’ Tyvaso inhalation solution, determined that only 2 out of 9 claims included in the patent were potentially patentable based on a review of prior art. Liquidia notes that the 2 remaining claims could still be invalidated on other grounds.
United Therapeutics filed suit against Liquidia in June 2020 alleging infringement of the ‘901 patent and US Patent No. 9,593,066 after the FDA initially accepted Liquidia’s NDA for LIQ861 treprostinil DPI for the treatment of pulmonary arterial hypertension (PAH). In July 2020, United Therapeutics added claims related to infringement of its newly-issued US Patent No. 10,716,793 (“Treprostinil administration by inhalation”) to the suit.
The FDA issued a complete response letter to the LIQ861 NDA in November 2020. Liquidia refiled the NDA in May 2021, and the FDA has recently completed a pre-approval inspection of Liquidia’s manufacturing facility. The agency has also recently granted priority review to United Therapeutics’ NDA for its own inhaled dry powder treprostinil, Tyvaso DPI. A 30-month stay on FDA approval of the LIQ861 NDA is set to expire on October 24, 2022 if the litigation has not been resolved by then.
Liquidia President and CEO Damian deGoa commented, “We are very pleased with this decision by the PTAB. This is a clear win in our on-going patent dispute with United Therapeutics, and we remain confident that we will ultimately prevail on all patent claims they have asserted against us. We will continue to vigorously defend our right to commercialize LIQ861 as soon as possible.”
Read the Liquidia Corporation press release.
