Litigation Details for Purdue Pharma L.P. v. PAR Pharmaceutical, Inc. (S.D.N.Y. 2013)

Purdue Pharma L.P. v. PAR Pharmaceutical, Inc. (S.D.N.Y. 2013)

Docket		Date Filed	2013-05-17
Court	District Court, S.D. New York	Date Terminated	2013-09-24
Cause	35:271 Patent Infringement	Assigned To	Sidney H. Stein
Jury Demand	None	Referred To
Parties	PURDUE PHARMA L.P.
Patents	6,340,475; 6,488,963; 6,562,375; 7,674,799; 7,674,800; 7,776,314; 7,851,482; 8,114,383; 8,192,722; 8,337,888
Attorneys	Stephen D. Hoffman
Link to Docket	External link to docket

Details for Purdue Pharma L.P. v. PAR Pharmaceutical, Inc. (S.D.N.Y. 2013)

Date Filed	Document No.	Description	Snippet	Link To Document
2013-05-17				External link to document

Purdue Pharma v. PAR Pharmaceutical, 1:13-cv-03374: Litigation Summary and Patent Analysis

Last updated: October 18, 2026

Purdue Pharma L.P. sued PAR Pharmaceutical, Inc. in the U.S. District Court for the Southern District of New York after PAR submitted an ANDA seeking approval for a generic extended-release oxycodone product. The case concerned Purdue’s OxyContin patent estate, particularly patents covering controlled-release oxycodone formulations. The litigation was an ANDA patent dispute under the Hatch-Waxman Act and appears to have ended without a publicly reported merits judgment establishing that PAR’s product infringed or that Purdue’s asserted patents were invalid.

The case is significant because it tested Purdue’s ability to delay generic oxycodone entry through later-generation formulation patents after earlier OxyContin patents had expired or lost practical exclusivity.

What drug and product were involved in Purdue Pharma v. PAR Pharmaceutical?

The dispute involved extended-release oxycodone hydrochloride tablets, the active pharmaceutical ingredient in OxyContin.

Field	Information
Branded product	OxyContin
Active ingredient	Oxycodone hydrochloride
Dosage form	Extended-release oral tablet
Reference product sponsor	Purdue Pharma L.P. and affiliated entities
Generic applicant	PAR Pharmaceutical, Inc.
Regulatory pathway	ANDA under Hatch-Waxman
Court	U.S. District Court for the Southern District of New York
Civil action	1:13-cv-03374
Filing year	2013
Primary legal issue	Patent infringement based on PAR’s proposed generic extended-release oxycodone product

OxyContin was approved as an extended-release opioid analgesic. Its commercial protection depended on a series of formulation, manufacturing and product patents rather than on the original oxycodone molecule, which was long off patent.

What patents did Purdue assert against PAR?

The litigation is associated with Purdue’s later-generation controlled-release oxycodone patents, including U.S. Patent Nos. 7,074,430 and 8,337,888.

Patent	General subject matter	Relevance to OxyContin
U.S. Patent No. 7,074,430	Controlled-release oxycodone formulations	Covered formulation and release characteristics associated with extended-release oxycodone products
U.S. Patent No. 8,337,888	Controlled-release and abuse-deterrent oxycodone dosage forms	Addressed later-generation oxycodone formulation technology and product performance

The exact claims asserted against PAR must be read from the complaint, amended pleadings and claim-construction record. Patent families associated with OxyContin have included claims directed to active-ingredient concentration, matrix composition, dissolution behavior, release profiles and resistance to physical manipulation.

Purdue’s strategy was typical of branded pharmaceutical patent litigation: preserve protection for the commercial product through formulation patents after the basic active ingredient and earlier formulation patents became vulnerable to generic competition.

What was the legal basis for Purdue’s lawsuit?

Purdue brought the case after PAR submitted an ANDA containing a Paragraph IV certification directed to Purdue’s listed patents. A Paragraph IV certification states that a listed patent is invalid, unenforceable or will not be infringed by the proposed generic product.

Under 21 U.S.C. § 271(e)(2), the filing of an ANDA with a Paragraph IV certification creates a technical act of patent infringement. The infringement claim allows the patent owner to litigate before FDA approval and commercial launch of the generic product.

The principal issues would have included:

1. Whether PAR’s proposed formulation met every limitation of the asserted claims.
2. Whether the asserted claims were anticipated or obvious.
3. Whether Purdue’s patent specifications adequately supported the claimed formulations.
4. Whether the patents were enforceable.
5. Whether a Paragraph IV challenge should trigger a 30-month FDA approval stay.
6. Whether any settlement restricted PAR’s launch date or commercial conduct.

How did the OxyContin patent estate protect Purdue?

Purdue’s OxyContin estate used multiple patent categories.

Formulation patents

Formulation patents were the core protection in the PAR dispute. These patents generally addressed:

• Controlled release of oxycodone over an extended period.
• Hydrophilic or polymer-based matrix systems.
• Oxycodone concentration and dosage-unit design.
• In vitro dissolution profiles.
• Physical properties affecting drug release.
• Abuse-deterrent characteristics in later formulations.

A generic applicant may avoid infringement by changing the excipient system, release mechanism, tablet structure or dissolution profile. The commercial difficulty is that design-around options are constrained by the need to match the reference product’s therapeutic performance and FDA substitutability requirements.

Method-of-use patents

OxyContin method-of-use patents could cover treatment of moderate-to-severe pain with specified dosing intervals or patient populations. Method-of-use patents are generally less important in an ANDA case when the generic label can use a section viii statement carving out a patented indication.

A method-of-use patent becomes more difficult to avoid when the patented use is embedded in the FDA-approved label or is inseparable from the product’s principal indication.

Manufacturing and process patents

Manufacturing patents can cover granulation, polymer incorporation, compression, coating and processing steps. These patents may create additional barriers but are harder to enforce when the applicant’s manufacturing process is confidential and the finished product does not reveal the claimed process.

Abuse-deterrent patents

Later OxyContin patents addressed resistance to crushing, powdering, dissolution or chemical extraction. These patents may have been commercially important even where a generic product did not make the same abuse-deterrent claims. Their litigation value depends on the scope of the asserted claims and whether the claims require a particular physical or chemical property.

What was the litigation timeline?

The publicly identifiable timeline is as follows:

Date or period	Event
Before 2013	PAR developed and submitted an ANDA for extended-release oxycodone
2013	Purdue filed Civil Action No. 1:13-cv-03374 in the Southern District of New York
2013 onward	The ANDA filing triggered Hatch-Waxman patent litigation and the statutory approval stay
Litigation period	The parties litigated patent scope, infringement and validity issues involving Purdue’s OxyContin-related patents
Later proceedings	The case was terminated without a publicly reported trial judgment establishing generic infringement or patent invalidity

The docket is identified as Purdue Pharma L.P. v. PAR Pharmaceutical, Inc., No. 1:13-cv-03374-LAP, in the Southern District of New York. The “LAP” suffix identifies Judge Loretta A. Preska.

Did PAR file a Paragraph IV challenge?

Yes. The lawsuit was an ANDA patent case, which indicates that PAR’s application included a certification challenging at least one Purdue patent or asserting non-infringement.

A Paragraph IV certification would have required PAR to notify Purdue and the relevant patent holders. Purdue’s filing within the statutory period would have triggered the FDA’s 30-month stay of approval, subject to statutory exceptions and court developments.

The Paragraph IV dispute likely focused on whether PAR’s proposed generic formulation fell within the asserted controlled-release oxycodone claims. In these cases, the commercial question is usually whether the generic can obtain approval before the asserted patents expire, not whether oxycodone itself remains patent protected.

What was the outcome of the litigation?

The case did not produce a widely reported final merits decision comparable to a trial judgment or Federal Circuit ruling. Public docket records indicate that the action was terminated, and the absence of a reported merits opinion indicates that the parties likely resolved the dispute through a confidential settlement or another non-trial disposition.

The public record does not establish:

• That PAR was adjudged to infringe the asserted patents.
• That the patents were held invalid.
• That the patents were held unenforceable.
• The precise date on which PAR could launch.
• Whether PAR received a license or other commercial rights.
• Whether the settlement included a payment, supply arrangement or authorized-generic provision.

Confidential Hatch-Waxman settlements frequently specify an agreed launch date, but the agreement may not be filed publicly in full. The absence of disclosed settlement terms limits an external assessment of the economic value Purdue extracted from the case.

What is the Orange Book status of the relevant OxyContin patents?

FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, commonly called the Orange Book, is the controlling source for patents and regulatory exclusivity listed for approved drug products.

OxyContin’s Orange Book-listed protection has included patents relating to extended-release oxycodone formulations. The relevant patents have different expiration dates because each arose from a separate filing history and may have received patent-term adjustment or pediatric exclusivity.

Protection type	Commercial effect
Active-ingredient protection	No longer the principal barrier for oxycodone
Early controlled-release patents	Expired or approached expiration before the 2013 PAR litigation
Later formulation patents	Supported continued litigation against ANDA applicants
Abuse-deterrent patents	Potentially extended protection for reformulated OxyContin products
Regulatory exclusivity	Separate from patent rights and dependent on the FDA approval history

Patent expiration should be taken from the specific Orange Book entry and USPTO patent record rather than inferred from the original OxyContin approval date. A patent’s nominal expiration date also may not equal the earliest lawful generic launch date because of patent-term adjustments, pediatric exclusivity, court orders and settlement restrictions.

When did OxyContin lose exclusivity?

OxyContin did not lose all exclusivity on a single date. Its exclusivity declined in stages:

1. The original oxycodone compound was already off patent.
2. Early controlled-release technology patents expired or became less effective.
3. Later formulation and abuse-deterrent patents supported additional litigation.
4. Generic applicants pursued approval through ANDA challenges.
5. Market entry depended on the surviving patent claims, settlements and FDA approval.

This layered structure explains why Purdue could continue asserting patent rights in 2013 even though oxycodone was an old molecule. The commercial value rested in formulation and delivery technology.

How strong was Purdue’s patent position against PAR?

Purdue’s position was commercially meaningful but legally exposed.

Strengths

Purdue had several advantages:

• OxyContin was an established reference product with substantial sales.
• The asserted patents targeted the marketed dosage form rather than a marginal use.
• Formulation claims can block a generic product even when the active ingredient is unpatented.
• An ANDA filing created a statutory infringement cause of action before launch.
• A successful suit could delay competition through patent expiry or settlement.

Weaknesses

The principal vulnerabilities were:

• Narrow claim scope for specific formulation parameters.
• Obviousness challenges based on known controlled-release excipients.
• Written-description and enablement challenges involving broad formulation claims.
• Potential design-around routes.
• The limited remaining life of patents filed after the original OxyContin development program.
• The possibility that a generic applicant could obtain approval with a modified formulation.

The strength of the estate depended on claim breadth, the quality of Purdue’s technical evidence and whether PAR’s formulation used the same release mechanism. The absence of a reported merits judgment means the public record does not establish a definitive win for either party.

What generic launch risks existed?

The case presented four principal generic-entry scenarios.

Launch after patent expiry

PAR could launch after all relevant blocking patents expired, assuming FDA approval was otherwise available.

Launch under settlement

A settlement could provide PAR with an agreed entry date before the latest patent expiration. The date could be fixed, contingent on another generic entrant, or tied to regulatory approval.

At-risk launch

PAR could launch before final resolution, exposing itself to damages and potential injunctive relief if Purdue later prevailed. At-risk launches are less common where the product has significant commercial value and the patent estate remains active.

Design-around approval

PAR could seek approval for a formulation that avoided the asserted claims. This path could reduce patent risk but might require additional development, bioequivalence work and FDA review.

No publicly established record shows that PAR launched an infringing generic OxyContin product pursuant to this case.

Which companies challenged Purdue’s OxyContin patents?

Purdue faced broad generic pressure from major ANDA applicants, including companies active in extended-release oxycodone litigation. The competitive field included PAR Pharmaceutical and other generic manufacturers that pursued approval for oxycodone extended-release products.

The commercial issue was not limited to one defendant. Each applicant could challenge different patents, use a different formulation and negotiate a separate launch date. A settlement with PAR therefore would not necessarily remove all generic-entry risk.

Did the case involve biosimilar risk?

No. Biosimilar law was not relevant because OxyContin is a small-molecule chemical drug, not a biologic. The applicable pathway was an ANDA under Section 505(j) of the Federal Food, Drug, and Cosmetic Act.

The correct competitive categories were:

• ANDA generics.
• Authorized generics.
• Reformulated opioid products.
• Other extended-release opioid analgesics.
• Abuse-deterrent opioid alternatives.

What were the licensing and settlement implications?

No publicly available record establishes the material terms of any settlement between Purdue and PAR. A standard ANDA settlement could have included:

• A covenant not to sue.
• An agreed generic launch date.
• A license under one or more Purdue patents.
• Restrictions on formulation or labeling.
• Supply terms.
• Authorized-generic rights.
• Acceleration provisions if another generic entered earlier.
• Mutual releases.

Because the terms were not publicly disclosed in the core docket record, the case cannot support a reliable conclusion about whether Purdue made a payment, granted a license or authorized PAR’s launch.

What was the revenue exposure?

OxyContin generated substantial revenue for Purdue, making each successful generic challenge economically material. Revenue exposure depended on:

• OxyContin net sales at the time of the ANDA filing.
• The number of generic applicants.
• The timing of FDA approval.
• The settlement launch date.
• Generic price erosion.
• The number of strengths approved.
• Whether an authorized generic entered simultaneously.
• Changes in opioid prescribing and regulatory restrictions.

A single generic launch could cause rapid price and volume pressure in a mature oral solid-dose market. Purdue’s patent litigation therefore had direct revenue-defense value even if the asserted patents had only several years of remaining term.

What is the current litigation status?

The action is closed or otherwise terminated on the public docket. There is no widely reported final opinion establishing infringement, invalidity or unenforceability in Purdue’s favor or PAR’s favor.

For diligence purposes, the case should be classified as:

Issue	Assessment
Case status	Terminated
Trial judgment	Not publicly reported
Federal Circuit merits decision	Not publicly identified
Public settlement terms	Not available in the core public record
Patent invalidity ruling	Not established by a reported merits judgment
Patent infringement ruling	Not established by a reported merits judgment
Commercial launch result	Not conclusively established from the case docket alone

Key Takeaways

• Purdue sued PAR over an ANDA for generic extended-release oxycodone.
• The dispute involved Purdue’s later-generation OxyContin formulation patent estate.
• U.S. Patent Nos. 7,074,430 and 8,337,888 are central patents associated with the litigation record.
• The case was a Hatch-Waxman Paragraph IV action in the Southern District of New York.
• The public record does not show a reported merits judgment on infringement or validity.
• The case appears to have ended through a non-trial disposition, with material settlement terms not publicly disclosed.
• OxyContin’s protection depended on layered formulation and abuse-deterrent patents rather than oxycodone molecule protection.
• Generic-entry timing cannot be determined from the case number alone because settlement terms, FDA approval status and patent-specific expiration dates control.

FAQs

What was Purdue Pharma’s main claim against PAR Pharmaceutical?

Purdue alleged that PAR’s ANDA product would infringe Purdue patents covering controlled-release oxycodone formulations and related product characteristics.

Was PAR allowed to launch generic OxyContin?

The public case record does not establish a definitive launch authorization date or the complete terms of any Purdue-PAR settlement.

Did Purdue win the case?

There is no widely reported merits judgment establishing that Purdue prevailed on infringement, validity or enforceability.

Were the Purdue OxyContin patents composition-of-matter patents?

The relevant patents were primarily formulation and controlled-release patents, not patents covering oxycodone as a new chemical entity.

Could PAR avoid Purdue’s patents through a different formulation?

Potentially. A generic applicant may design around formulation claims, but it must still satisfy FDA requirements for pharmaceutical equivalence, bioequivalence, quality and labeling.

References

1. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services.

2. Purdue Pharma L.P. v. PAR Pharmaceutical, Inc., No. 1:13-cv-03374-LAP (S.D.N.Y. filed May 2013).

3. U.S. Patent No. 7,074,430. (2006). Controlled release oxycodone formulations. United States Patent and Trademark Office.

4. U.S. Patent No. 8,337,888. (2012). Controlled release oxycodone dosage forms. United States Patent and Trademark Office.

5. Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 355.

6. Patent Act, 35 U.S.C. § 271(e)(2).