Two months ago, when a federal appeals court rejected United Therapeutics’ attempt to revive an invalidated patent on its aging pulmonary arterial hypertension drug Tyvaso (treprostinil), it cleared one hurdle for the FDA to approve a rival treatment from the North Carolina-based Liquidia Corporation.
Now, United is using a different tactic to thwart the potential competitor as it is challenging the FDA, questioning the thoroughness of its approval process for Liquidia’s Yutrepia.
In a lawsuit filed (PDF) on Wednesday, United alleges that the FDA allowed Liquidia to sidestep “rules, precedents and procedures” in adding an amendment to its pending submission for a new drug application (NDA) in September of last year. The amendment seeks to add a second indication—pulmonary hypertension associated with interstitial lung disease (PH-ILD)—which United claims should only be approved by way of a separate NDA.
The FDA apparently has questions about its procedure as well. The lawsuit comes four weeks after the regulator delayed its decision on an approval of Yutrepia, which carried a target decision date of Jan. 24.
In a release the following day, Liquidia explained that the FDA is “confirming the process for adding the PH-ILD indication as an amendment to the NDA,” noting that the regulator did not request any additional clinical data and did not issue a new decision date.
Liquidia submitted its application for approval of Yutrepia in 2020, and, a year later, the FDA tentatively blessed it, signing off on its efficacy and safety.
Wednesday, Liquidia had no comment other than to say it was “reviewing the news and the lawsuit,” according to Chief Business Officer Jason Adair.
The FDA, for its part, said that it does not comment on pending litigation.
United also presented its fourth-quarter and annual earnings on Wednesday, revealing record revenue of $2.33 billion for 2023, which was a 20% jump from 2022, due to booming sales of Tyvaso. The drug reached $1.23 billion in revenue for the year, up 41% from 2022, with $731 million coming from United’s new dry powder formulation of the treatment.
Tyvaso DPI was approved in May 2022 as an alternative to the original nebulized version, which saw sales fall 30% to $512 billion last year. United added the PH-ILD indication for Tyvaso in April of 2021. Liquidia’s Yutrepia is a DPI formulation as well.
United has inked settlements allowing generics makers to begin selling copycats of nebulized Tyvaso starting in January 2026, according to an annual Securities and Exchange Commission filing published Wednesday.
United's action against the FDA has drawn the attention of Public Innovation Project (PIP), an advocacy group which called the lawsuit a "sham."
"United Therapeutics offers a case study in Big Pharma’s abuse of the patent system undermining actual innovation,” said Joshua Lamel, executive director of PIP. “UTC’s record revenue is directly fueled by a patent abuse strategy on the Big Pharma giant’s treprostinil products that continues to support expectation-busting profits while blocking patient access to medications that could help them achieve better health outcomes.”