Purdue Pharma v. Accord Healthcare: OxyContin Patent Struck Down After Bench Trial
Purdue Pharma and Purdue Pharmaceuticals LP sued Accord Healthcare over US Patent No. 11,304,908, asserting that Accord’s ANDA filing for a generic OxyContin® formulation constituted infringement. After a February 2024 bench trial before Judge William C. Bryson, the Delaware District Court declared six asserted claims invalid for obviousness — a decisive win for the generic challenger after 794 days of litigation.
How Accord Defeated Purdue’s OxyContin® Patent at Bench Trial
Filed on 8 July 2022 in the District of Delaware, this Hatch-Waxman ANDA litigation pitted branded opioid manufacturer Purdue Pharma L.P. and Purdue Pharmaceuticals L.P. against generic challengers Accord Healthcare Ltd. and Accord Healthcare Inc. USA. The core dispute centred on US Patent No. 11,304,908, covering extended-release oxycodone hydrochloride formulations marketed as OxyContin®. Purdue alleged that Accord’s submission of ANDA No. 213564 constituted infringement of the ‘908 patent.
The case proceeded to a bench trial the week of 12 February 2024 before Senior Judge William C. Bryson, sitting by designation. On 9 September 2024, the Court issued findings of fact and conclusions of law declaring claims 1, 10, 18, 23, 28, and 29 of the ‘908 patent invalid for obviousness under 35 U.S.C. § 103. Judgment was entered in Accord’s favour on all infringement claims, and all remaining claims and counterclaims — including those touching US11304909B2 — were dismissed without prejudice as moot, subject to reinstatement on reversal or remand.
The 794-day duration from filing to final judgment is consistent with contested Hatch-Waxman bench trials in Delaware, though notably the obviousness finding — rather than a claim-construction or enablement ruling — suggests the Court found the formulation advances claimed by Purdue were not sufficiently differentiated from the prior art. What drove settlement talks, if any, or why Purdue did not concede earlier remains unaddressed in the public record. Purdue retains the option to appeal to the Federal Circuit.
Filing to Dismissed without Prejudice in 794 days
794 days from filing to judgment — longer than the typical ANDA patent bench trial average of ~600 days
Bench trial verdict: what the obviousness finding means for both parties
Obviousness under § 103 — the patent’s core weakness
A finding of obviousness under 35 U.S.C. § 103 means the Court concluded that a person of ordinary skill in the pharmaceutical formulation arts could have arrived at the claimed OxyContin® composition by combining prior art references. This is a merits-level invalidity ruling — not a procedural dismissal — and carries presumptive weight in any subsequent ANDA litigation involving the same patent and similar prior art.
Invalidity — § 103 obviousnessPurdue’s ‘908 patent loses enforceability against Accord
With claims 1, 10, 18, 23, 28, and 29 declared invalid, Purdue cannot enforce the ‘908 patent to block Accord’s ANDA product in this proceeding. The ruling does not automatically cancel the patent — it binds Accord specifically — but it signals material vulnerability for Purdue if other generic filers assert the same prior art. Purdue’s remaining patent, US11304909B2, was dismissed without prejudice and may be litigated separately if circumstances change.
Enforceability impairedAccord clears a key patent obstacle to generic OxyContin® approval
Accord’s ANDA No. 213564 now faces one fewer patent barrier. An obviousness judgment in Accord’s favour supports its paragraph IV certification and may accelerate FDA approval timelines. The without-prejudice dismissal of remaining claims also limits Purdue’s ability to immediately relitigate US11304909 on the same facts, though that patent is not extinguished. This outcome is commercially significant for Accord’s generic oxycodone pipeline.
ANDA pathway clearedExtended-release opioid IP now under heightened scrutiny
This ruling is likely to embolden other ANDA filers challenging Purdue’s extended-release opioid portfolio with obviousness arguments built on similar prior art. For branded pharmaceutical companies, the decision suggests that formulation patents characterised by incremental improvements over established controlled-release technology face a high obviousness bar in Delaware courts. Generic entrants in the oxycodone space should monitor any Federal Circuit appeal closely.
Generic entry risk elevatedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Purdue Pharma | Individual | Branded opioid manufacturer — holder of US11304908 (OxyContin® extended-release formulation)Search in Eureka ↗ |
| Co-Plaintiff | Purdue Pharmaceuticals, LP | Company | Search in Eureka ↗ |
| Defendant | Accord Healthcare, Ltd. | Company | Generic pharmaceutical manufacturer seeking ANDA approval for oxycodone HCl extended-release tabletsSearch in Eureka ↗ |
| Co-Defendant | Accord Healthcare, Inc. USA | Company | Search in Eureka ↗ |
| Plaintiff counsel | Gasper J. LaRosa | Attorney | Counsel for Purdue PharmaSearch in Eureka ↗ |
| Plaintiff counsel | Jack B. Blumenfeld | Attorney | Counsel for Purdue PharmaSearch in Eureka ↗ |
| Plaintiff counsel | Jason G. Winchester | Attorney | Counsel for Purdue PharmaSearch in Eureka ↗ |
| Plaintiff counsel | John J. Normile | Attorney | Counsel for Purdue PharmaSearch in Eureka ↗ |
| Plaintiff counsel | Kevin V. Mccarthy | Attorney | Counsel for Purdue PharmaSearch in Eureka ↗ |
| Plaintiff counsel | Megan Elizabeth Dellinger | Attorney | Counsel for Purdue PharmaSearch in Eureka ↗ |
| Plaintiff counsel | Rodger Dallery Smith , II | Attorney | Counsel for Purdue PharmaSearch in Eureka ↗ |
| Plaintiff counsel | Sarah A. Geers | Attorney | Counsel for Purdue PharmaSearch in Eureka ↗ |
| Plaintiff law firm | Morris, Nichols, Arsht & Tunnell LLP | Law Firm | Representing Purdue PharmaSearch in Eureka ↗ |
| Defendant counsel | Aaron F. Barkoff | Attorney | Counsel for Accord Healthcare, Ltd.Search in Eureka ↗ |
| Defendant counsel | Alejandro J. Menchaca | Attorney | Counsel for Accord Healthcare, Ltd.Search in Eureka ↗ |
| Defendant counsel | Ben J. Mahon | Attorney | Counsel for Accord Healthcare, Ltd.Search in Eureka ↗ |
| Defendant counsel | Benjamin J. Schladweiler | Attorney | Counsel for Accord Healthcare, Ltd.Search in Eureka ↗ |
| Defendant counsel | Renee Mosley Delcollo | Attorney | Counsel for Accord Healthcare, Ltd.Search in Eureka ↗ |
| Defendant law firm | Greenberg Traurig LLP | Law Firm | Representing Accord Healthcare, Ltd.Search in Eureka ↗ |
| Presiding judge | Judge William C. Bryson | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The Court’s final judgment is precise and consequential: six named claims are declared invalid — not merely unenforceable — on an affirmative obviousness finding under § 103 following a full bench trial on the merits. This is a merits disposition, not a procedural ruling, and carries collateral estoppel implications for Accord in any future proceeding on the same claims. The without-prejudice dismissal of remaining claims preserves Purdue’s right to revive US11304909B2 litigation only if the Federal Circuit reverses or remands the core obviousness ruling — a carefully constructed judicial safety valve.
US11304908B2 — OxyContin® extended-release oxycodone HCl formulation
US11304908B2 (application no. US17/027222) is a United States utility patent protecting formulations of extended-release oxycodone hydrochloride — the active ingredient in Purdue’s flagship OxyContin® product. The patent’s claims, as litigated, covered specific compositional and formulation parameters of the controlled-release matrix. Filing in the US17/027222 application series places it in a family of patents Purdue built around its abuse-deterrent and extended-release opioid technology, a domain that has seen sustained litigation activity since the original OxyContin® reformulation.
The commercial stakes of the ‘908 patent are substantial: OxyContin® has historically been one of the highest-revenue branded opioid products in the US market. By asserting the ‘908 patent against Accord’s ANDA, Purdue sought the standard 30-month stay under Hatch-Waxman to delay generic entry. The Court’s obviousness ruling, however, removes this barrier for Accord and signals that the formulation claims in this patent family may be vulnerable to well-constructed prior art arguments — a significant strategic blow for Purdue’s remaining exclusivity position.
Should your team run an FTO against US11304908B2 and US11304909B2?
Any pharmaceutical company developing or planning to commercialise extended-release oxycodone or structurally analogous opioid formulations should treat this case as an active FTO signal. The ‘908 patent’s claims have been adjudicated invalid for obviousness, but the patent remains nominally in force pending any appeal. US11304909B2 was dismissed without prejudice and retains its presumption of validity. Generic filers, contract manufacturers, and branded reformulators in the opioid or controlled-release pain management space should assess their exposure to the ‘909 patent independently.
PatSnap Eureka’s FTO Search Agent can map your formulation’s feature set against the claim scope of US11304908B2 and US11304909B2, surface relevant prior art cited in the Delaware proceedings, and flag related family members that may cover adjacent formulation parameters. For R&D teams designing around Purdue’s extended-release platform, Eureka can identify the white-space between the invalidated claims and the broader patent family — reducing the risk of inadvertent infringement of surviving claims.
Run a freedom-to-operate analysis on US11304909B2 to assess your product’s exposure
Run FTO in Eureka →Similar ANDA patent invalidity cases in Delaware District Court
Explore related Hatch-Waxman bench trial decisions in Delaware involving extended-release pharmaceutical formulation patents challenged on obviousness grounds.
What this case signals for the pharmaceutical IP landscape
The ‘908 invalidity ruling has ripple effects across the extended-release opioid patent estate and ANDA litigation strategy broadly.
Formulation patents need clear technical differentiation from prior art
The Court’s obviousness finding suggests Purdue’s claimed formulation advances were insufficiently distinguished from existing controlled-release oxycodone art. Pharmaceutical IP teams should audit whether their formulation patents articulate a non-obvious technical problem-solution nexus, not merely incremental compositional variation, before filing enforcement actions.
ANDA challengers can use this ruling as prior art leverage in similar proceedings
An obviousness ruling against the ‘908 patent, once final, creates persuasive precedent for other generic filers asserting the same prior art against related Purdue formulation patents. IP counsel advising ANDA applicants should review the Court’s findings of fact for citable prior art combinations that survived Purdue’s secondary considerations arguments.
Pharma v Accord — key questions answered
The Delaware District Court held, after a February 2024 bench trial, that claims 1, 10, 18, 23, 28, and 29 of US11304908B2 are invalid for obviousness under 35 U.S.C. § 103. Judgment was entered in Accord’s favour. Remaining claims, including those relating to US11304909B2, were dismissed without prejudice as moot.
US11304908B2 (application US17/027222) is a US utility patent owned by Purdue Pharma covering formulations of extended-release oxycodone hydrochloride — the active ingredient in OxyContin®. Purdue asserted the patent against Accord’s ANDA No. 213564, which sought FDA approval for a generic version of OxyContin® tablets.
A § 103 obviousness finding by a district court after a full bench trial is a merits judgment. It means the Court concluded the claimed formulation would have been obvious to a skilled formulator based on prior art. While the ruling binds Accord specifically and does not automatically cancel the patent, it creates significant collateral estoppel risk in any subsequent ANDA proceeding involving the same claims and similar prior art.
Yes. Purdue may appeal the Final Judgment to the United States Court of Appeals for the Federal Circuit. The judgment explicitly preserves Purdue’s right to reinstate dismissed claims relating to US11304909B2 if the Federal Circuit reverses or remands the core obviousness ruling on the ‘908 patent. No appeal had been publicly recorded at the time of publication.
US11304909B2 was named in the litigation but the claims relating to it were dismissed without prejudice as moot following the Court’s invalidity ruling on US11304908B2. This means the patent was not adjudicated on the merits and retains its presumption of validity. It may be litigated afresh if Purdue successfully appeals the ‘908 ruling, or in separate proceedings.
PatSnap Eureka searches patents and litigation data to answer instantly.