Litigation Details for Endo Pharmaceuticals Inc. v. Impax Laboratories Inc. (D. Del. 2008)

Endo Pharmaceuticals Inc. v. Impax Laboratories Inc. (D. Del. 2008)

Docket		Date Filed	2008-01-25
Court	District Court, D. Delaware	Date Terminated	2009-02-24
Cause	35:271 Patent Infringement	Assigned To	Katharine S. Hayden
Jury Demand	None	Referred To
Parties	IMPAX LABORATORIES INC.
Patents	7,276,250
Attorneys	Julia Heaney
Firms	Morris, Nichols, Arsht & Tunnell
Link to Docket	External link to docket

Details for Endo Pharmaceuticals Inc. v. Impax Laboratories Inc. (D. Del. 2008)

Date Filed	Document No.	Description	Snippet	Link To Document
2008-01-25				External link to document

Endo Pharmaceuticals v. Impax (1:08-cv-00057): Litigation Summary, Patent-Esque Risk Signals, and Generic-Entry Impact

Last updated: June 17, 2026

Endo Pharmaceuticals Inc. v. Impax Laboratories Inc., 1:08-cv-00057, is a Hatch-Waxman patent-infringement action in which Endo sought to block Impax’s proposed generic entry for an Endo-branded product. The case is procedurally tied to a Paragraph IV posture and typically resolves through stipulations, settlements, or court rulings that define the launch timing and design-around pathways. The decision impacts downstream “when can Impax launch” timelines and informs patent-strength and generic-risk assessments for investors and licensing partners tracking Endo’s estate.

What were the allegations in Endo Pharmaceuticals Inc. v. Impax Laboratories Inc. | 1:08-cv-00057?

A Hatch-Waxman infringement case at this docket number implies:

• Endo (plaintiff) asserted one or more patents listed for the brand in the FDA Orange Book.
• Impax (defendant) filed an ANDA containing a Paragraph IV certification against one or more listed patents.
• Endo alleged that Impax’s generic product would infringe the asserted claims (literal infringement and/or doctrine-of-equivalents), or would induce/contribute to infringement through marketing and use.

Which Endo product was at issue

The party names and docket format identify the dispute as Endo vs. Impax in the 2008 timeframe, but the specific drug name, strength, dosage form, and asserted Orange Book patents are not contained in the provided input. Without the case caption text showing the FDA product and asserted patent numbers, the litigation summary cannot be mapped to particular claims and cannot be used to compute launch-impact dates.

Which patents were asserted

A complete litigation “analysis” for this matter requires:

• asserted patent numbers
• claim construction posture (if any)
• infringement theories and defenses
• whether validity was litigated (anticipation/obviousness, indefiniteness, lack of written description, inequitable conduct, prosecution-history estoppel)

No patent numbers or holdings are present in the input, so a claim-by-claim infringement/validity breakdown cannot be produced accurately.

What happens procedurally in a Paragraph IV case like 1:08-cv-00057?

For this docket class, the procedural sequence usually determines the business outcome more than the merits:

1. ANDA filing and Paragraph IV certification by Impax
2. Notice of Paragraph IV to Endo, triggering the 45-day window
3. Infringement suit filed within 45 days of notice
4. 30-month stay (if triggered by timely suit), unless lifted by a court finding or settlement
5. Early rulings (preliminary injunction unlikely in Hatch-Waxman; summary judgment is common)
6. Markman/claim construction if the court reaches claim terms
7. Final judgment or settlement setting generic launch terms

How the 30-month stay affects “when can Impax launch?”

In business terms, the key question is whether the case ends before or after the 30-month mark, and whether a settlement grants an agreed launch date or continued exclusivity until a later triggering date.

A concrete “launch date” analysis requires the docket’s procedural endpoints (dismissal timing, settlement date, any lifting of the stay). None are included in the input.

When does Endo’s exclusivity expire in Endo v. Impax | 1:08-cv-00057?

“Exclusivity” in Hatch-Waxman disputes breaks into two tracks:

• Regulatory exclusivities (New Chemical Entity, new formulation, pediatric extensions)
• Patent exclusivities defined by Orange Book listed patents

To answer “when it loses exclusivity,” the following must be tied to the case:

• the Orange Book listing(s) that were litigated
• the specific patent expiration(s)
• whether the case involved method-of-use, formulation, or device/combination aspects
• whether pediatric exclusivity or terminal disclaimers extend the useful blocking window

The input does not identify the litigated patents or the FDA product, so an exclusivity expiration timeline cannot be computed.

Which patents protect the Endo product in this dispute, and how many?

To produce an “estate map,” the response needs:

• Orange Book “listed drug” name
• Orange Book “patent list” numbers tied to the brand
• patent assignees and expiration dates
• status (expired, active, surrendered, or delisted)

Without the Orange Book identifiers or case caption details listing the patents, any count of “how many patents cover” would be speculative.

What is the Orange Book status tied to 1:08-cv-00057?

Orange Book status analysis typically includes:

• Orange Book “listed patents” at the time of ANDA submission
• Paragraph IV vs. Paragraph I/II/III posture by Impax
• whether the asserted patents were the sole blocking patents
• whether any subsequent amendments changed the patent list

No Orange Book data is provided in the prompt.

Did Impax succeed, and what did the court order in 1:08-cv-00057?

A litigation summary that is decision-grade must state:

• whether Endo obtained a judgment of infringement
• whether patents were found invalid or not infringed
• whether the case was dismissed on procedural grounds
• whether the parties entered a settlement agreement and its launch terms
• whether an injunction entered or was waived in settlement

The input contains only the docket number and party names. It includes no judgment/disposition date, no settlement terms, and no procedural outcome.

How strong was the patent estate for Endo in this case?

Patent strength analysis depends on:

• claim construction outcomes
• the trial record or dispositive motions
• prior art and obviousness landscape
• enablement/written description issues
• prosecution history, including disclaimers and estoppel

None of those inputs are present.

What settlement or stipulation terms typically follow in Endo v. Impax?

Hatch-Waxman settlements commonly include:

• agreed effective date of generic launch
• “non-at-risk” launch conditions
• payment structures (if any) and covenants-not-to-sue
• design-around paths if there are formulation/method differences

A settlement analysis cannot be made without the settlement date and terms, which are not provided.

Which companies were challenging Endo’s patents alongside Impax?

Co-defendants and other ANDA filers can appear depending on:

• multiple Paragraph IV suits consolidated
• later-filed ANDAs with similar certifications
• related cases before the same or different judges

No other parties are supplied.

How does this case affect biosimilar or biologic competition risk?

This case caption names Impax Laboratories and Endo Pharmaceuticals. The matters at this docket format typically involve small-molecule ANDAs, not biologics. A biosimilar analysis would require confirmation that the asserted product is a biologic (BLA) and whether any biosimilar was at issue.

No product identity is provided.

What are the generic entry risks for other ANDA filers after 1:08-cv-00057?

Generic-entry risk analysis depends on:

• whether the asserted patents were upheld
• whether the decision narrowed claim scope
• whether the case created collateral estoppel or persuasive non-infringement/validity findings
• whether the settlement established a “best” design-around template

Without case disposition, the risk cannot be tied to legal outcomes.

Key Takeaways

• Endo v. Impax, 1:08-cv-00057, is a Hatch-Waxman-style patent infringement dispute tied to Paragraph IV ANDA activity.
• A litigation summary that maps to patent numbers, claim outcomes, and launch timing cannot be completed from the provided input because no asserted patent list, disposition, or settlement terms are included.
• The business impact in these cases generally turns on (1) whether the 30-month stay lifted early, (2) whether patents were invalidated or not infringed, or (3) whether the parties settled on a defined generic launch date.

FAQs

1) What does a “1:08-cv-00057” Hatch-Waxman docket generally cover?
A civil action tied to a Paragraph IV ANDA, alleging infringement of Orange Book-listed patents and seeking to prevent generic market entry pending resolution.

2) How do court outcomes in Paragraph IV cases affect FDA approval versus launch?
FDA approval can be separate from launch; even if an ANDA is approved, a patent injunction or settlement terms can still delay market entry.

3) What evidence typically drives infringement findings in these cases?
Product comparison (labels, specs), claim construction, and expert testimony linking the generic’s features to asserted claim limitations.

4) What legal triggers lift the 30-month stay?
A final court decision on infringement/invalidity before 30 months or a settlement that supersedes the stay, depending on docket events.

5) How do settlements in Endo-style cases usually structure entry timing?
They often define an agreed launch date, covenant not to sue, and rules around design-arounds and at-risk manufacturing.

References

1. Federal Court docket entry for Endo Pharmaceuticals Inc. v. Impax Laboratories Inc., No. 1:08-cv-00057.