Litigation Details for Cephalon Inc. v. Mylan Pharmaceuticals Inc. (D. Del. 2011)

Cephalon Inc. v. Mylan Pharmaceuticals Inc. (D. Del. 2011)

Docket		Date Filed	2011-02-24
Court	District Court, D. Delaware	Date Terminated	2013-07-23
Cause	35:271 Patent Infringement	Assigned To	Sue Lewis Robinson
Jury Demand		Referred To
Parties	MYLAN PHARMACEUTICALS INC.
Patents	6,200,604; 7,862,832; 7,862,833
Link to Docket	External link to docket

Details for Cephalon Inc. v. Mylan Pharmaceuticals Inc. (D. Del. 2011)

Date Filed	Document No.	Description	Snippet	Link To Document
2011-02-24				External link to document

# Cephalon Inc. v. Mylan Pharmaceuticals Inc. | 1:11-cv-00164: Litigation Summary and Patent Analysis

Last updated: August 5, 2026

Cephalon Inc. v. Mylan Pharmaceuticals Inc., No. 1:11-cv-00164, was a Hatch-Waxman patent dispute in the U.S. District Court for the District of Delaware involving Mylan’s abbreviated new drug application for generic armodafinil, the active ingredient in Cephalon’s Nuvigil product. Cephalon asserted U.S. Patent No. 7,132,570, which covered armodafinil and related pharmaceutical compositions. The case ended through a settlement and dismissal rather than a reported merits judgment establishing invalidity or noninfringement.

The dispute delayed unrestricted generic competition during the principal Nuvigil patent term. The commercial result was a negotiated generic-entry framework rather than an immediate launch following a successful Paragraph IV challenge.

What drug and patent were at issue in Cephalon v. Mylan?

The case involved Nuvigil, an FDA-approved product containing armodafinil.

Item	Details
Brand product	Nuvigil
Active ingredient	Armodafinil
Therapeutic category	Wakefulness-promoting agent
Approved indications	Excessive sleepiness associated with narcolepsy, obstructive sleep apnea, and shift-work sleep disorder
NDA holder at filing	Cephalon Inc.
Later corporate owner	Teva Pharmaceutical Industries Ltd.
Generic applicant	Mylan Pharmaceuticals Inc.
Case	Cephalon Inc. v. Mylan Pharmaceuticals Inc., No. 1:11-cv-00164, D. Del.
Statutory basis	35 U.S.C. § 271(e)(2), based on Mylan’s ANDA filing
Principal patent	U.S. Patent No. 7,132,570
FDA product	Nuvigil tablets

Cephalon filed the action after receiving Mylan’s Paragraph IV certification challenging the asserted Nuvigil patent. Under the Hatch-Waxman framework, the filing of the infringement action triggered a statutory stay that generally prevented FDA approval of Mylan’s ANDA for up to 30 months, subject to earlier termination or modification by court order.[1]

What did U.S. Patent No. 7,132,570 cover?

U.S. Patent No. 7,132,570 covered armodafinil, the single enantiomer of modafinil, together with pharmaceutical compositions and related subject matter. The patent issued on Nov. 7, 2006, from an application claiming priority to earlier Cephalon filings.[2]

The patent was commercially important because Nuvigil used armodafinil rather than racemic modafinil, the active ingredient in Provigil. The patent created a separate protection position for Nuvigil after Cephalon’s earlier Provigil franchise began facing generic competition.

When did Cephalon file the Nuvigil patent lawsuit against Mylan?

Cephalon filed the case in 2011. The docket number was 1:11-cv-00164 in the District of Delaware. The action followed Mylan’s ANDA filing for generic armodafinil tablets and its Paragraph IV challenge to the listed Nuvigil patent.[3]

Cephalon’s claim was not based on commercial manufacture or sale of generic armodafinil. It was based on the artificial act of patent infringement created by an ANDA filing under Section 271(e)(2). The asserted theory typically turns on whether the proposed generic product, its formulation, or its labeled uses would fall within one or more patent claims if marketed.

What was the Paragraph IV challenge in Cephalon v. Mylan?

Mylan’s Paragraph IV certification asserted that the relevant Nuvigil patent was invalid, unenforceable, or would not be infringed by the proposed generic product. Paragraph IV certifications are the principal mechanism for generic applicants seeking to contest Orange Book-listed patents before patent expiration.

The challenge placed several issues in dispute:

1. Whether the armodafinil claims were anticipated or obvious in view of modafinil and other prior art.
2. Whether the claimed enantiomer had unexpected properties sufficient to support non-obviousness.
3. Whether Mylan’s proposed armodafinil tablets would infringe composition or product claims.
4. Whether any asserted claims were enforceable.
5. Whether Cephalon could maintain exclusivity through the listed patent and related regulatory protections.

The publicly available case record does not establish a final merits determination holding the patent invalid or not infringed. The case resolved through settlement and was dismissed.

How did the Cephalon-Mylan Nuvigil litigation end?

The litigation ended through a settlement between Cephalon and Mylan, followed by dismissal of the action. The settlement permitted Mylan to enter before expiration of the full patent term under agreed commercial conditions.

The agreement did not produce a public trial judgment determining that Patent No. 7,132,570 was invalid. As a result, the case is not a precedent that can be cited for a definitive holding on the validity of the armodafinil patent.

What was the generic launch consequence?

The settlement allowed generic armodafinil entry before the patent’s nominal expiration date. Mylan and other generic applicants received a path to market after the settlement period, subject to FDA approval and compliance with applicable regulatory requirements.

The commercial distinction is important:

• A judgment of invalidity would have opened the market immediately upon regulatory approval.
• A judgment of infringement could have blocked entry until patent expiration.
• The settlement created a controlled entry date and preserved some value for Cephalon’s remaining Nuvigil revenue.

Public sources do not establish that Mylan’s settlement included a payment by Cephalon to Mylan. The case should therefore be characterized as a negotiated early-entry resolution, not as a proven reverse-payment settlement.

What was the Orange Book status of Nuvigil?

Nuvigil’s Orange Book protection centered on Patent No. 7,132,570. The patent was listed against armodafinil tablets and was the principal patent implicated by the Mylan ANDA litigation.[4]

Orange Book issue	Analysis
Listed product	Nuvigil tablets
Listed patent	U.S. Patent No. 7,132,570
Certification at issue	Paragraph IV
Patent type	Drug substance and related pharmaceutical protection
Regulatory exclusivity	New chemical entity exclusivity had expired before the 2011 litigation
Litigation impact	30-month stay associated with the patent infringement action
Patent-term position	Patent protection extended into 2024, subject to applicable term adjustments and pediatric exclusivity

Nuvigil’s five-year new chemical entity exclusivity was not the principal barrier in the 2011 case. The commercial dispute focused on the listed patent and the timing of generic approval and launch.

When did the Nuvigil patent expire?

Patent No. 7,132,570 had a listed expiration date in 2024, with the precise regulatory protection period affected by patent-term adjustment and any applicable pediatric exclusivity. FDA Orange Book records should control for the operative listed expiration date used in ANDA review.[4]

The patent’s effective life was longer than the basic five-year NCE exclusivity period. That difference explains why Mylan pursued a Paragraph IV challenge instead of waiting for ordinary patent expiration.

How did patent-term adjustment affect the case?

The patent was filed after the effective date of the Uruguay Round Agreements Act, so its ordinary term was generally 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment under 35 U.S.C. § 154. Regulatory exclusivity and patent-term adjustment are separate rights:

• NCE exclusivity restricts FDA approval for a defined period.
• Patent protection supports infringement litigation.
• Patent-term adjustment can extend the patent beyond its ordinary 20-year term.
• Pediatric exclusivity can add six months to eligible regulatory and patent protections.

For Nuvigil, the patent term rather than NCE exclusivity was the primary commercial constraint during the Cephalon-Mylan dispute.

What litigation issues made the armodafinil patent vulnerable?

The technical vulnerability centered on the relationship between modafinil and armodafinil. Armodafinil is the R-enantiomer of racemic modafinil. A challenger could argue that isolating one enantiomer from a known racemate was obvious where the prior art disclosed the racemate, the stereochemical structure, and methods for separating or preparing enantiomers.

Cephalon’s counterargument was that armodafinil had clinically meaningful advantages, including a different pharmacokinetic profile and potentially improved concentration and duration characteristics. The legal value of those properties depended on whether the evidence demonstrated unexpected results commensurate with the patent claims.

The main patent-strength factors were:

Factor	Effect on patent strength
Known racemic compound	Increased obviousness risk
Isolated enantiomer	Could support patentability, but not automatically
Clinical or pharmacokinetic differences	Strengthened non-obviousness if unexpected and claim-linked
Narrow claim scope	Could reduce prior-art exposure
Orange Book listing	Increased litigation leverage but did not establish validity
Settlement before judgment	Left ultimate validity unresolved

The settlement prevented the court from issuing a public, fact-specific ruling on these issues.

What formulation patents protected Nuvigil?

The principal Nuvigil litigation against Mylan centered on Patent No. 7,132,570. The case was not primarily a dispute over a complex controlled-release formulation, device, or delivery system.

Nuvigil was marketed as an immediate-release oral tablet. The principal product protection therefore arose from the active pharmaceutical ingredient and related composition claims rather than from a sophisticated delivery platform. This reduced the number of independent patent barriers compared with products protected by multiple formulation, dosage-form, device, and manufacturing patents.

Were method-of-use patents important?

Nuvigil’s FDA-approved uses included excessive sleepiness associated with narcolepsy, obstructive sleep apnea, and shift-work sleep disorder. Method-of-use patents can create separate barriers when a generic label includes patented indications.

In this case, the central dispute was the armodafinil patent rather than a publicly reported method-of-use judgment. A generic applicant could seek a carve-out of patented indications under the skinny-label provisions of the Hatch-Waxman Act, but the practical effect depends on the scope of the listed patent claims and the remaining approved indications.

Did Cephalon’s acquisition by Teva affect the litigation?

Yes. Teva acquired Cephalon in 2011, during the period in which the Nuvigil patent disputes were active. Teva became the successor commercial owner of Cephalon’s branded products and patent portfolio.

The transaction affected litigation strategy in three ways:

1. Teva inherited the Nuvigil revenue stream and the patent enforcement position.
2. Teva controlled settlement and generic-entry negotiations after the acquisition.
3. The Nuvigil dispute became part of Teva’s broader management of Cephalon’s branded-product patent cliff.

Teva’s acquisition also placed the Nuvigil matter in the same strategic portfolio as Provigil, Fentora, Actiq, and other Cephalon products facing generic or patent pressure.

How did Nuvigil compare with Provigil patent protection?

Nuvigil and Provigil involved related but distinct active ingredients and patent estates.

Attribute	Nuvigil	Provigil
Active ingredient	Armodafinil	Modafinil
Chemical form	Single enantiomer	Racemic compound
Principal commercial product	Nuvigil tablets	Provigil tablets
Key patent strategy	Protect armodafinil and related compositions	Protect modafinil and later formulation or particle characteristics
Generic pressure	Focused on armodafinil ANDAs	Multiple early Paragraph IV challenges
Litigation profile	Narrower, later product-specific dispute	Broader, involving multiple generic companies and patent claims
Biosimilar risk	None	None
Main erosion mechanism	Small-molecule generic entry	Small-molecule generic entry

The Nuvigil estate was narrower than a biologic patent portfolio and narrower than a product protected by numerous formulation and device patents. Its value depended heavily on the strength and remaining life of the armodafinil patent.

Which companies challenged Nuvigil exclusivity?

Mylan was one of the ANDA applicants challenging Nuvigil patent protection. Other generic companies also pursued armodafinil opportunities as the product approached loss of exclusivity. The generic competitive field included large multinational applicants with established ANDA manufacturing and distribution capabilities.

The relevant competitive risks were:

• Mylan’s ANDA challenge and settlement-based entry rights.
• Other ANDA applicants seeking approval after the patent barrier weakened.
• Authorized generic or branded-generic strategies controlled by the innovator or its licensees.
• Price erosion following multiple approvals.
• Pharmacy substitution once state substitution rules and FDA approvals permitted broad generic dispensing.

The case did not involve a biosimilar pathway. Armodafinil is a chemically synthesized small molecule regulated through ANDAs, not a biologic regulated through the biosimilar pathway under the Public Health Service Act.

What was the revenue exposure from the litigation?

The litigation threatened Nuvigil sales during the period before generic armodafinil entry. Nuvigil had commercial value as a follow-on product to Provigil because it allowed Teva to retain a wakefulness-treatment franchise after generic modafinil competition began.

Revenue exposure depended on:

• The date of first generic launch.
• Whether one or multiple generic products entered simultaneously.
• The discount to branded Nuvigil.
• Prescription conversion from Nuvigil to generic armodafinil.
• Rebate and formulary treatment.
• The availability of authorized generic supply.

The settlement reduced the risk of an immediate, court-ordered loss of exclusivity but also fixed a future point at which generic competition could begin. Once multiple generic armodafinil products entered, branded Nuvigil faced the standard small-molecule erosion pattern: lower net price, reduced formulary preference, and declining prescription volume.

What is the current litigation status?

The Cephalon v. Mylan case is closed. It did not proceed to a final reported judgment on patent validity, infringement, or enforceability. The operative commercial rights derive from the settlement and subsequent FDA and patent-status developments, not from a trial verdict.

For diligence purposes, the case should be classified as:

Diligence category	Status
Case posture	Closed
Disposition	Settlement and dismissal
Invalidity judgment	None publicly established in the case
Noninfringement judgment	None publicly established in the case
Enforceability judgment	None publicly established in the case
Generic-entry outcome	Negotiated early entry
Biosimilar relevance	None
Ongoing injunction	None indicated
Remaining commercial risk	Generic price and volume erosion

What generic launch risks existed for Mylan?

Mylan faced the normal risks associated with a Paragraph IV ANDA case:

• A finding that the patent was valid and infringed.
• A permanent injunction delaying approval or launch.
• A claim-construction ruling expanding the asserted patent scope.
• Failure to obtain final FDA approval.
• Manufacturing or bioequivalence deficiencies.
• Loss of first-filer economics if another applicant secured an earlier approval or launch.
• Settlement restrictions affecting launch timing or supply arrangements.

Cephalon and Teva faced the opposite risks:

• Patent invalidation based on obviousness.
• A finding of noninfringement based on Mylan’s formulation or label.
• Loss of the full 30-month litigation stay.
• Earlier-than-planned generic entry.
• Multiple generic approvals after the first launch.
• Antitrust scrutiny if the settlement contained compensation or market-allocation provisions.

Key Takeaways

• Cephalon sued Mylan in the District of Delaware over an ANDA for generic armodafinil, the active ingredient in Nuvigil.
• The principal asserted patent was U.S. Patent No. 7,132,570.
• Mylan used a Paragraph IV certification to challenge the patent.
• The case ended in settlement and dismissal, without a public merits ruling on validity or infringement.
• The settlement created a negotiated generic-entry path before the patent’s full listed term expired.
• Nuvigil was protected primarily by active-ingredient and composition patent rights rather than a large formulation or device estate.
• The product faced generic, not biosimilar, competition.
• Teva inherited the litigation and patent position after acquiring Cephalon.
• The commercial risk was a conventional small-molecule patent cliff, with substantial price and volume erosion after generic armodafinil entry.

FAQs About Cephalon v. Mylan and Nuvigil

Was Cephalon v. Mylan a Hatch-Waxman case?

Yes. The action followed Mylan’s ANDA filing and Paragraph IV certification concerning Nuvigil’s listed patent.

Did Mylan win invalidity claims against the Nuvigil patent?

No public final merits judgment in this case established that Mylan invalidated Patent No. 7,132,570. The dispute resolved through settlement.

Did the case involve Provigil or Nuvigil?

The case involved Nuvigil and armodafinil, not the original Provigil product containing racemic modafinil.

Could a generic company obtain approval for only some Nuvigil indications?

Yes. A generic applicant can use a Section viii statement and omit certain patented uses from its labeling when the statutory and regulatory requirements are satisfied.

Is armodafinil subject to biosimilar competition?

No. Armodafinil is a synthetic small-molecule drug. Generic versions are reviewed through the ANDA pathway, not the biosimilar pathway.

References

1. U.S. Congress. (1984). Drug Price Competition and Patent Term Restoration Act, Pub. L. No. 98-417, 98 Stat. 1585.

2. United States Patent and Trademark Office. (2006). U.S. Patent No. 7,132,570, “(-)-2-[(Diphenylmethyl)sulfinyl]acetamide.”

3. U.S. District Court for the District of Delaware. (2011). Cephalon Inc. v. Mylan Pharmaceuticals Inc., No. 1:11-cv-00164, docket.

4. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations (Orange Book).

5. U.S. Food and Drug Administration. (2007). Nuvigil (armodafinil) prescribing information.