United Timber v. Liquidia Technologies: Federal Circuit Affirms (22-2133)
United Timber Corp. appealed a patentability ruling against US9604901B2 — a process patent covering synthesis of treprostinil, the active ingredient in Remodulin®. The Federal Circuit affirmed the lower decision after 679 days, leaving the invalidity finding intact and Liquidia’s treprostinil pathway undisturbed.
Federal Circuit seals treprostinil process patent invalidity on appeal
United Timber Corp. filed appeal No. 22-2133 at the Court of Appeals for the Federal Circuit on 18 August 2022, challenging a patentability ruling concerning US9604901B2. That patent covers a chemical process for preparing treprostinil — the prostacyclin analogue that serves as the active pharmaceutical ingredient in United Therapeutics’ Remodulin®, a treatment for pulmonary arterial hypertension. Liquidia Technologies, Inc. was the respondent, having previously succeeded on an invalidity or cancellation action against the patent at the tribunal below.
On 27 June 2024, the Federal Circuit issued an affirmance, finding no reversible error in the decision below. An affirmance at this level is dispositive: the invalidity or cancellation finding against US9604901B2 is now confirmed by the nation’s primary patent appellate court, and the patent cannot be revived through further proceedings at the same appellate tier. The basis of termination is recorded as ‘Appeal Dismissed,’ which in Federal Circuit practice is consistent with a merits affirmance that formally closes the appellate docket.
The 679-day duration from filing to closure is notable and suggests substantive merits engagement rather than a quick procedural resolution. The case turned on patentability — specifically invalidity or cancellation — of a pharmaceutical process patent, a technically dense area where claim construction and prior art analysis typically drive length. What drove the precise scope of the affirmance, and whether any individual claim survived, is not fully disclosed in the public termination record.
Filing to Appeal Dismissed in 679 days
679 days — longer than the median Federal Circuit appeal, suggesting substantive briefing complexity
Federal Circuit affirms: what the ruling means for both parties
Affirmance means the lower decision stands without reversible error
When the Federal Circuit issues an affirmance, it has reviewed the record and found no legal or factual error significant enough to disturb the tribunal below. In a patentability/invalidity context, this means the cancellation or invalidity finding against US9604901B2 is now confirmed at the highest specialist patent appellate level in the US. No further rehearing at this tier is available as of right.
Invalidity confirmed on appealUS9604901B2 cannot be enforced: invalidity finding now final
For United Timber Corp., the affirmance extinguishes the patent rights conferred by US9604901B2 as a practical matter. The process claims covering treprostinil synthesis have been held invalid, and that holding is now backed by Federal Circuit authority. Any licensing programme or exclusivity strategy that relied on this patent is materially impaired. The only remaining avenue would be a petition for certiorari to the Supreme Court, which is rarely granted in patent cases.
Patent rights extinguishedLiquidia secures freedom to operate its treprostinil process
Liquidia Technologies emerges from this appeal with the invalidity finding affirmed, meaning the process patent that could have blocked or encumbered its treprostinil manufacturing pathway is no longer a live threat. This is strategically significant for a company developing inhaled treprostinil products: cleared process IP lowers the risk of injunctive relief and damages exposure in future infringement proceedings tied to this specific patent.
Process freedom confirmedTreprostinil process IP landscape tilts toward generic and biosimilar entrants
An affirmed invalidity ruling on a key treprostinil synthesis process patent signals that at least one previously asserted process barrier has been cleared. For the broader PAH drug sector, this suggests competitors developing treprostinil-based therapies should audit remaining process patents in the Remodulin® portfolio — this ruling does not clear all process claims, but it raises the bar for enforcing closely related synthetic-route patents and may embolden further IPR or cancellation challenges.
PAH market entry barrier reducedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | United Timber, Corp. | Company | Patent appellant asserting US9604901B2 — treprostinil synthesis process patentSearch in Eureka ↗ |
| Defendant | Liquidia Technologies, Inc. | Company | Clinical-stage biopharmaceutical company developing inhaled treprostinil productsSearch in Eureka ↗ |
| Plaintiff counsel | Adam William Burrowbridge | Attorney | Counsel for United Timber, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Arthur Paul Dykhuis | Attorney | Counsel for United Timber, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Douglas H. Carsten | Attorney | Counsel for United Timber, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Jaime Santos | Attorney | Counsel for United Timber, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Jenny J. Zhang | Attorney | Counsel for United Timber, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Rohiniyurie Tashima | Attorney | Counsel for United Timber, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Shaun R. Snader | Attorney | Counsel for United Timber, Corp.Search in Eureka ↗ |
| Plaintiff counsel | William Covington Jackson | Attorney | Counsel for United Timber, Corp.Search in Eureka ↗ |
| Plaintiff counsel | William M. Jay | Attorney | Counsel for United Timber, Corp.Search in Eureka ↗ |
| Plaintiff law firm | Goodwin Procter LLP | Law Firm | Representing United Timber, Corp.Search in Eureka ↗ |
| Plaintiff law firm | McDermott Will & Emery LLP | Law Firm | Representing United Timber, Corp.Search in Eureka ↗ |
| Defendant counsel | Jonathan Davies | Attorney | Counsel for Liquidia Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Sanya Sukduang | Attorney | Counsel for Liquidia Technologies, Inc.Search in Eureka ↗ |
| Defendant law firm | Cooley LLP | Law Firm | Representing Liquidia Technologies, Inc.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The single-word verdict — AFFIRMED — reflects the Federal Circuit’s standard of review: legal questions such as claim construction are reviewed de novo, while underlying factual findings (e.g., anticipation, obviousness) are reviewed for substantial evidence when arising from an administrative tribunal. An affirmance signals the court found the patentability/invalidity determination was legally sound and supported by the record. For US9604901B2, this means the cancellation or invalidity holding is now binding and no longer subject to revision at the appellate level.
US9604901B2 — Treprostinil synthesis process for Remodulin®
US9604901B2 (application no. US14/754932) protects a chemical process for preparing treprostinil — a prostacyclin analogue approved for the treatment of pulmonary arterial hypertension and sold by United Therapeutics as Remodulin®. Process patents of this type protect the manufacturing route rather than the compound itself, making them a critical secondary layer of exclusivity for branded pharmaceutical manufacturers seeking to delay generic or follow-on entry even after compound patents expire or are challenged.
In the PAH therapeutics sector, treprostinil has attracted sustained IP litigation because of its commercial value and the number of companies seeking to develop inhaled or injectable generics. A process patent on synthesis is strategically significant: it can block competing manufacturers even if the active molecule is unpatented or off-patent. The affirmance of invalidity against US9604901B2 removes one such barrier, but competitors must audit the broader United Therapeutics and related patent estate to assess residual process and formulation risk before proceeding with treprostinil development programmes.
Should you run an FTO against US9604901B2 and related treprostinil process patents?
Any company developing, manufacturing, or commercialising treprostinil-based therapies — including inhaled, subcutaneous, or oral formulations — should treat this ruling as a prompt to refresh their FTO analysis. While US9604901B2 has been held invalid and affirmed as such, the broader Remodulin® patent estate includes additional process, formulation, and method-of-use patents that remain live. Relying on this single affirmance without a full landscape review creates residual infringement exposure.
PatSnap Eureka’s FTO Search Agent can map the complete treprostinil patent family, flag active process and formulation claims, and surface prior art that may support further invalidity positions. For R&D and regulatory teams preparing an ANDA, 505(b)(2) application, or biosimilar pathway, a structured FTO report anchored to the current claim status of each surviving patent is essential before committing to a manufacturing route or clinical programme.
Run a freedom-to-operate analysis on US9604901B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit appeals involving pharmaceutical process patent invalidity
Cases involving Federal Circuit review of process patent invalidity in small-molecule pharmaceutical synthesis, particularly in the pulmonary and cardiovascular drug space.
What this case signals for the treprostinil and PAH patent IP landscape
A Federal Circuit affirmance on a pharmaceutical process patent carries durable precedential weight — here is what practitioners and product teams should take away.
Process patent invalidity at the Federal Circuit is final for practical purposes
With US9604901B2 held invalid and the Federal Circuit affirming, United Timber’s enforcement options are effectively exhausted. IP teams tracking the treprostinil space should remove this patent from active freedom-to-operate risk registers. Supreme Court certiorari petitions in patent cases succeed at well below 1%, making this outcome near-definitive.
Liquidia’s treprostinil process clearance strengthens its commercial position in PAH
For companies watching competitive dynamics in pulmonary arterial hypertension therapies, Liquidia’s win on this process patent suggests its manufacturing pathway is more defensible. R&D teams at rival developers should map which remaining process patents in the Remodulin® cluster are still live, as this ruling does not extinguish the full portfolio.
United v Liquidia — key questions answered
The Federal Circuit affirmed the lower patentability/invalidity ruling against US9604901B2 on 27 June 2024. The affirmance means the Federal Circuit found no reversible error, and the invalidity or cancellation finding against the treprostinil synthesis process patent is now confirmed at the appellate level.
US9604901B2 protects a chemical process for preparing treprostinil, the active pharmaceutical ingredient in Remodulin®, used to treat pulmonary arterial hypertension. Process patents of this kind can block competing manufacturers from using specific synthesis routes even when the underlying compound is not independently patented, making them strategically important for both brand holders and generic developers.
The affirmance clears the specific process patent US9604901B2 as a barrier for Liquidia, but it does not clear the entire treprostinil IP estate. Other process, formulation, or method-of-use patents held by United Therapeutics or related entities may remain active. A comprehensive FTO analysis is required before drawing conclusions about full freedom to operate.
The appeal was filed on 18 August 2022 and closed on 27 June 2024, a duration of 679 days. This is longer than a typical Federal Circuit appeal, suggesting substantive merits briefing and potentially oral argument, though the specific procedural steps are not fully disclosed in the public record.
In Federal Circuit practice, ‘Appeal Dismissed’ as a docket closure basis is consistent with a merits affirmance that formally closes the appellate proceeding. It does not necessarily imply a purely procedural dismissal without merits review — the AFFIRMED verdict is the operative legal outcome, confirming the lower decision on patentability stands.
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