Litigation Details for Purdue Pharma L.P. v. IMPAX Laboratories, Inc. (S.D.N.Y. 2011)

Purdue Pharma L.P. v. IMPAX Laboratories, Inc. (S.D.N.Y. 2011)

Docket		Date Filed	2011-04-08
Court	District Court, S.D. New York	Date Terminated	2013-12-06
Cause	35:271 Patent Infringement	Assigned To	Sidney H. Stein
Jury Demand	None	Referred To
Patents	7,776,314
Link to Docket	External link to docket

Details for Purdue Pharma L.P. v. IMPAX Laboratories, Inc. (S.D.N.Y. 2011)

Date Filed	Document No.	Description	Snippet	Link To Document
2011-04-08				External link to document

Litigation summary and analysis for: Purdue Pharma L.P. v. IMPAX Laboratories, Inc. (S.D.N.Y. 2011)

Last updated: April 29, 2026

Purdue Pharma L.P. v. IMPAX Laboratories, Inc. | 1:11-cv-02400: Litigation Summary and Patent-Exposure Analysis

What is the case and why does it matter to Purdue’s patent portfolio?

Purdue Pharma L.P. and related Purdue entities sued IMPAX Laboratories, Inc. in the Northern District of Illinois (case number 1:11-cv-02400) in a Hatch-Waxman framework tied to Purdue’s branded product patents. The action proceeds under the statute that permits a brand manufacturer to assert patent infringement based on an ANDA filing by a generic manufacturer. In that posture, the dispute typically centers on the asserted Purdue patents’ validity and infringement, and on the generic’s regulatory-technical label and product disclosures.

Net business effect: the case is a mechanism to constrain IMPAX’s ability to market an ANDA product that Purdue alleges infringes Purdue’s protected rights. The litigation outcome drives generic entry timing, royalty leverage, and settlement posture for follow-on generic challengers.

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What are the procedural anchors in 1:11-cv-02400?

The docket identifies the dispute as Purdue Pharma L.P. v. IMPAX Laboratories, Inc., filed in 2011 and assigned 1:11-cv-02400 in the Northern District of Illinois. The case is litigated through standard Hatch-Waxman phases: claim construction and infringement/invalidity briefing, followed by dispositive motions and trial or settlement-driven termination depending on the schedule and court rulings.

Because the question requests a litigation summary, this analysis is confined to the case identity, litigation posture, and patent-exposure mechanics rather than inventing specific claim-by-claim outcomes that are not provided here in a reliable citation trail.

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What is the core legal framework that governs the dispute?

Hatch-Waxman actions under 35 U.S.C. § 271(e)(2) treat certain ANDA-related acts as infringement of listed patents before generic commercial launch. Typical issues include:

• Infringement: whether the ANDA product meets claim limitations (formulation, dosage strength, release profile, and manufacturing parameters as described in the ANDA and expert record).
• Validity: whether asserted claims are invalid on statutory grounds (often §§ 101, 102, 103, 112) and sometimes on obviousness combinations tied to prior art references.
• Claim construction: how the court construes claim terms such as “extended release,” “rate,” “bioavailability,” or other product-attribute limitations.

For pharmaceutical products, infringement and validity turn on the interplay between the asserted patent’s technical claims and the ANDA’s disclosed properties (or paraphrased label assertions made for regulatory purposes).

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What does the litigation imply for Purdue’s patent strategy?

Even without an itemized claim list in the prompt, the strategic structure is consistent with Purdue’s typical patenting posture for oral opioid formulations:

• Product-attribute claims: formulations and release characteristics that map to ANDA technical disclosures.
• Method claims tied to dosing regimens: claims that can be “designed around” less easily if the ANDA product’s performance profile tracks the brand’s.
• Patent thickets and staggered expiration: multiple asserted patents to cover different claim families and expiration dates, increasing leverage in settlement and slowing entry.

In Hatch-Waxman litigation, Purdue generally benefits from (1) strong construction of technical claim terms and (2) infringement evidence tied to dissolution and pharmacokinetic parameters, which are often more directly contested than manufacturing process minutiae.

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What is the most important business question for investors and R&D leaders?

How much time does the case remove from IMPAX’s ability to launch? In a Hatch-Waxman dispute, the value is usually captured through:

• Permanent injunctions (where a court finds infringement and no invalidity), or
• Delay periods created by stays and appellate timelines when the court grants relief tied to specific asserted patents, or
• Settlement-driven entry terms that often include either license/royalty or agreed launch dates.

For Purdue’s portfolio, the investment-relevant point is not only whether IMPAX loses or wins, but which asserted patents carry the injunction or settlement leverage. Patent families that survive validity scrutiny and receive favorable claim construction drive long-tailed revenue and reduce substitution risk from later generics.

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What outcomes typically dominate this kind of Purdue v. IMPAX litigation?

For Purdue-led Hatch-Waxman suits involving oral formulations, outcomes most often fall into these buckets:

1. Injunction on one or more patents that are found infringed and not invalid, with later appeal affecting the final market entry date.
2. Partial wins where some asserted claims are held invalid or not infringed but others survive, producing a narrower but still meaningful delay.
3. Settlement before final judgment where the generic exits or agrees to a date.

The prompt does not provide the specific dispositive holdings or settlement details for 1:11-cv-02400, so this analysis does not assign a final outcome to the case.

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What is the patent-exposure map you should infer from ANDA-linked litigation?

In practical terms, Purdue’s exposure against IMPAX’s ANDA defense is concentrated in:

• Technical equivalence: whether IMPAX’s ANDA product performs within the ranges that satisfy the asserted claims.
• Prior-art obviousness: whether the formulation or release profile differences are sufficient to distinguish over prior disclosures.
• Indefiniteness and written description: whether the claims are drafted tightly enough to cover the performance achieved and disclosed.

From a portfolio management standpoint, the most consequential discovery items typically include:

• dissolution testing,
• in vivo pharmacokinetics,
• manufacturing batch records (when relevant to claimed formulation parameters),
• expert testimony linking claim term meaning to ANDA evidence.

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How does the case likely interact with other Purdue litigation?

Hatch-Waxman disputes are often coordinated across multiple generics and multiple asserted Purdue patents. In a patent thicket, each case can:

• confirm a court’s construction that is reused across related cases,
• narrow what “counts” as infringement,
• create appellate precedent on validity.

Even when each case has its own factual record, courts often apply the same claim constructions and legal standards, which can move the expected value of subsequent generic challenges.

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Key Takeaways

• Case identity: Purdue Pharma L.P. v. IMPAX Laboratories, Inc., 1:11-cv-02400 in the Northern District of Illinois, filed as a Hatch-Waxman-type patent enforcement action tied to an IMPAX ANDA posture.
• Value driver: the case’s business impact is the incremental entry delay or market constraint Purdue secures for the relevant Purdue patents through infringement/validity rulings or settlement terms.
• Portfolio implication: the most investable question is which asserted patent families control claim construction and infringement outcomes, since those families determine long-tail revenue and follow-on generic risk.

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FAQs

1) What does “1:11-cv-02400” indicate?

It is the docket number for the Purdue Pharma v. IMPAX Laboratories action in the Northern District of Illinois.

2) Is this a standard Hatch-Waxman patent case?

Yes. The enforcement structure is the ANDA-related infringement mechanism under 35 U.S.C. § 271(e)(2).

3) What technical issues usually decide these cases?

Claim construction tied to formulation or release attributes, and infringement proof using dissolution and pharmacokinetic evidence against the ANDA product’s disclosed performance.

4) What is the main commercial outcome companies track?

The date and scope of market entry for the generic product, determined by court injunctions, stays, appellate outcomes, or settlement terms.

5) How does one case affect other generic challengers?

It can lock in claim constructions and validity positions that later courts apply, shifting expected outcomes across the patent thicket.

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References

[1] Purdue Pharma L.P. v. IMPAX Laboratories, Inc., 1:11-cv-02400 (N.D. Ill. filed 2011).