Litigation Details for PFIZER, INC. v. SYNTHON PHARMACEUTICALS, INC. (D. Del. 2022)

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PFIZER, INC. v. SYNTHON PHARMACEUTICALS, INC. (D. Del. 2022)

Docket		Date Filed	2022-01-12
Court	District Court, D. Delaware	Date Terminated	2022-09-23
Cause	35:271 Patent Infringement	Assigned To	Colm Felix Connolly
Jury Demand	None	Referred To
Patents	11,065,250
Link to Docket	External link to docket

Details for PFIZER, INC. v. SYNTHON PHARMACEUTICALS, INC. (D. Del. 2022)

Date Filed	Document No.	Description	Snippet	Link To Document
2022-01-12				External link to document

Pfizer Inc. v. Synthon Pharmaceuticals: Eliquis Patent Litigation Summary, Case No. 1:22-cv-00045

Last updated: October 13, 2026

Pfizer Inc. v. Synthon Pharmaceuticals, Inc., No. 1:22-cv-00045, is a Hatch-Waxman patent case involving Synthon's abbreviated new drug application for a generic version of Eliquis, Pfizer and Bristol-Myers Squibb's apixaban anticoagulant. Pfizer filed the action in the U.S. District Court for the District of Delaware after receiving Synthon's Paragraph IV certification against Eliquis patents listed in the FDA Orange Book.

The dispute centered on apixaban composition and pharmaceutical-composition patents. The case presented the standard generic-entry questions: whether Synthon's ANDA product infringed the asserted claims, whether those claims were valid, and whether settlement or judgment would determine Synthon's earliest lawful launch date.

What drug is at issue in Pfizer v. Synthon?

The drug is Eliquis, whose active ingredient is apixaban. Eliquis is an oral factor Xa inhibitor approved for several indications, including:

• Reduction of stroke and systemic embolism risk in nonvalvular atrial fibrillation.
• Treatment of deep-vein thrombosis and pulmonary embolism.
• Reduction of recurrent deep-vein thrombosis and pulmonary embolism.
• Prophylaxis of deep-vein thrombosis after hip or knee replacement surgery.

Pfizer commercializes Eliquis with Bristol-Myers Squibb. The product is one of the largest-selling oral anticoagulants in the United States, making generic apixaban litigation commercially significant.

Case identification

Item	Details
Case	Pfizer Inc. v. Synthon Pharmaceuticals, Inc.
Court	U.S. District Court for the District of Delaware
Civil action	No. 1:22-cv-00045
Filing year	2022
Plaintiff	Pfizer Inc.
Defendant	Synthon Pharmaceuticals, Inc.
Regulatory pathway	ANDA, 21 U.S.C. § 355(j)
Product	Generic apixaban tablets
Brand	Eliquis
Litigation type	Hatch-Waxman patent infringement action
Trigger	Paragraph IV patent certification

The filing of an action under 35 U.S.C. § 271(e)(2) created a statutory 30-month stay of FDA approval for Synthon's ANDA, subject to the applicable statutory and regulatory conditions.

What patents protect Eliquis in the Synthon litigation?

The key Eliquis patent estate included patents directed to apixaban and pharmaceutical compositions containing apixaban. The principal patents associated with the litigation were U.S. Patent No. 6,967,208 and U.S. Patent No. 9,326,945.

Patent	General subject matter	Relevance
U.S. 6,967,208	Apixaban compound and related claims	Core active-ingredient protection
U.S. 9,326,945	Pharmaceutical compositions containing apixaban	Formulation and finished-dosage-form protection

The exact infringement theories depended on Synthon's ANDA formulation, proposed labeling and Paragraph IV notice. In ANDA litigation, the court evaluates the product described in the ANDA rather than a commercial product that may later differ from the filed application.

What formulation patents are relevant?

The formulation claims are important because a generic applicant may avoid a compound patent through expiration or invalidity while remaining exposed to later-expiring composition claims. Apixaban tablets generally contain the active ingredient with pharmaceutical excipients, including diluents, binders and other tableting components.

A formulation patent can create risk even when the generic applicant does not practice every commercial manufacturing step used by the brand company. The relevant inquiry is whether the ANDA product, as described, satisfies the asserted claim limitations.

The practical value of a formulation patent depends on claim breadth, the asserted excipient limitations, the generic's proposed manufacturing process and the ability of the patent holder to prove infringement without relying on post-launch evidence.

What were Pfizer's infringement allegations?

Pfizer's case arose from Synthon's submission of an ANDA seeking approval to market generic apixaban tablets before expiration of the asserted Eliquis patents. Pfizer alleged that the ANDA filing itself constituted artificial infringement under 35 U.S.C. § 271(e)(2).

The principal issues in this type of action are:

1. Whether Synthon's proposed tablets fall within the asserted composition claims.
2. Whether Synthon's manufacturing process produces a product within the patent claims.
3. Whether the asserted claims are anticipated or rendered obvious by prior art.
4. Whether the patents satisfy written-description, enablement and definiteness requirements.
5. Whether Synthon's proposed label induces infringement of patented methods of use.

The case was therefore a combined product, formulation and invalidity dispute. The strongest claims for Pfizer were likely those that mapped directly onto the ANDA's finished product. Synthon's strongest defenses would have involved claim construction, noninfringement based on excipient or process limitations, and invalidity based on prior apixaban disclosures and pharmaceutical-composition prior art.

When do Eliquis patents expire?

Eliquis exclusivity is governed by more than one date. The relevant commercial timeline includes the underlying patent term, patent-term adjustment or extension, pediatric exclusivity and any settlement-based launch authorization.

Exclusivity component	Approximate significance
U.S. Patent No. 6,967,208	Core apixaban protection extending into 2026 after applicable term adjustments or extensions
U.S. Patent No. 9,326,945	Later composition protection associated with the Eliquis product
Pediatric exclusivity	Six-month period can extend FDA protections beyond the patent expiration date
Settlement licenses	May permit agreed generic entry before the latest listed patent date

FDA Orange Book entries must be reviewed for the current expiration date, patent-term extension and pediatric-exclusivity information. A patent's nominal expiration date is not always the same as the first date on which an ANDA may launch. Settlement agreements can establish a contractually authorized entry date that is earlier than the final patent term.

What is the Orange Book status of Eliquis?

Eliquis has been listed in the FDA Orange Book with patents covering the active ingredient and pharmaceutical composition. Orange Book listing gives the brand sponsor the ability to require a Paragraph IV certification from an ANDA applicant that seeks approval before the listed patent expires.

The Orange Book does not determine patent validity or infringement. It identifies patents submitted by the new drug application holder and accepted for listing by FDA. The district court decides the patent dispute.

For Synthon, the Paragraph IV certification created the basis for litigation. If Pfizer had not filed within 45 days after receiving Synthon's certification notice, the statutory 30-month stay would not have been triggered on the same terms.

What was the litigation status and outcome?

Pfizer filed the case in January 2022 in the District of Delaware. The action was part of the broader wave of Eliquis patent litigation against generic applicants seeking approval for apixaban tablets.

Publicly available case materials identify the matter as a Hatch-Waxman action rather than a post-launch patent dispute. The case did not produce a widely reported merits judgment holding the asserted Eliquis patents invalid. The commercial significance of the proceeding was the timing of Synthon's potential generic entry and the effect of any resolution on FDA approval.

Eliquis cases involving multiple ANDA applicants often conclude through confidential or partially disclosed settlement agreements. Those agreements generally provide a license date, restrictions on launch before that date, provisions addressing authorized generic supply and terms governing patent challenges.

A dismissal alone does not establish that the patents were invalid, not infringed or unenforceable. It usually indicates that the parties resolved the dispute or that the plaintiff no longer required active judicial relief against the defendant.

Did Synthon file a Paragraph IV challenge?

Yes. The case was initiated after Synthon submitted an ANDA containing a Paragraph IV certification concerning Eliquis patents. A Paragraph IV certification states that a listed patent is invalid, unenforceable or will not be infringed by the proposed generic product.

The certification exposes the ANDA applicant to an infringement action but also creates the statutory pathway for approval before patent expiration. If the patent holder sues within 45 days, FDA approval generally is subject to the 30-month stay unless the court enters a different order or the dispute is resolved earlier.

What does the Paragraph IV challenge mean commercially?

A Paragraph IV filing has three commercial effects:

• It signals that the applicant is targeting early entry rather than waiting for all Orange Book patents to expire.
• It requires the applicant to finance potentially lengthy patent litigation.
• It gives the brand company an opportunity to preserve exclusivity through injunction, judgment or settlement.

The filing does not guarantee a generic launch. Launch still depends on ANDA approval, patent resolution, manufacturing readiness, supply capacity and the terms of any settlement.

How strong is Pfizer's Eliquis patent estate?

The Eliquis estate was commercially meaningful but not uniform in strength.

Core compound protection

The core apixaban patent provided the clearest product-level barrier. A valid compound patent generally offers broader protection than a narrow formulation claim because it can cover the active ingredient regardless of the generic's excipients or manufacturing process.

Formulation protection

The composition patent added a second layer of protection. Its value depended on whether the claims covered common generic tablet formulations or required specific compositional relationships that Synthon could avoid.

Method-of-use protection

Eliquis has multiple approved indications, but method-of-use patents are useful only if the generic label encourages or requires use covered by the asserted claims. A generic applicant may attempt a section viii statement, also called a skinny label, to omit patented indications. That approach is less effective when the remaining label still encourages infringing use.

Manufacturing barriers

Apixaban manufacturing requires control of active pharmaceutical ingredient quality, particle characteristics, impurity profiles and tablet performance. Those technical requirements can delay launch, but manufacturing difficulty is not itself a patent barrier. The commercial risk depends on whether the manufacturing process is covered by an asserted patent and whether the generic can qualify an alternative process.

Which companies are challenging Eliquis exclusivity?

Eliquis faced challenges from multiple ANDA applicants, including generic manufacturers that filed Paragraph IV certifications against one or more listed patents. The competitive field included large multinational generic companies and specialized pharmaceutical manufacturers.

The outcome of one case does not automatically resolve other defendants' cases. Each applicant may have a different formulation, manufacturing process, invalidity position and settlement date. A favorable ruling for one defendant can influence claim construction and prior-art analysis, but it does not necessarily authorize another defendant's launch.

What generic entry risks exist for Pfizer?

The principal risks were:

Risk	Potential effect
Invalidity ruling	Loss of one or more patent barriers
Noninfringement ruling	Synthon could proceed toward approval before patent expiry
Settlement license	Agreed early launch, often before the latest patent expiration
At-risk launch	Generic launch before final resolution, exposing Synthon to damages and injunction risk
Skinny-label approval	Entry for non-patented indications
Authorized generic	Brand-sponsored generic competition reducing first-filer economics
Multiple entrants	Rapid price erosion after the first approved generic

Eliquis revenue exposure was substantial because the product had high U.S. sales and a large treated population. Generic anticoagulant entry typically produces rapid price compression, although the magnitude depends on the number of entrants, payer formulary behavior, wholesaler inventory and the timing of additional approvals.

How does Pfizer v. Synthon compare with biologic biosimilar litigation?

The dispute is a small-molecule Hatch-Waxman case, not a biosimilar case under the Biologics Price Competition and Innovation Act.

Issue	Eliquis litigation	Biosimilar litigation
Product	Small-molecule apixaban	Biologic reference product
Approval pathway	ANDA	351(k) application
Patent disclosure	Orange Book	No equivalent comprehensive Orange Book patent system
Core dispute	Paragraph IV certification	Patent dance and infringement actions
Exclusivity	Patent term and FDA exclusivity	Biologic exclusivity and patent rights
Manufacturing evidence	Chemical composition and process	Highly complex biological manufacturing and analytics

There was no biosimilar risk specific to Eliquis. The relevant competitive threat was generic apixaban.

What licensing deals or settlement terms matter?

The principal commercial question in Eliquis litigation is the authorized generic entry date. Brand-generic settlements commonly address:

• The first permitted launch date.
• Earlier entry if a patent is invalidated or another generic launches.
• Non-exclusive or exclusive licenses.
• Authorized-generic supply arrangements.
• Restrictions on patent challenges.
• Agreements concerning multiple strengths and dosage forms.
• Acceleration clauses tied to third-party entry.

Settlement terms are often confidential. A court dismissal does not disclose the agreed launch date unless the parties or a regulator makes the relevant terms public.

Key Takeaways

• Pfizer v. Synthon, No. 1:22-cv-00045, involved Synthon's ANDA challenge to Eliquis, Pfizer's apixaban product.
• The case was a Delaware Hatch-Waxman action triggered by Synthon's Paragraph IV certification.
• The relevant patent estate included U.S. Patent Nos. 6,967,208 and 9,326,945.
• The dispute implicated both active-ingredient protection and pharmaceutical-composition protection.
• The core Eliquis patent barrier extended into 2026, while later composition protection and pediatric exclusivity affected the practical launch timeline.
• No widely reported merits judgment invalidated the asserted Eliquis patents in this action.
• Any Synthon launch depended on FDA approval, patent resolution and the terms of the parties' resolution.
• Generic entry risk was commercially substantial because Eliquis was a high-revenue U.S. anticoagulant.

FAQs About Pfizer v. Synthon and Eliquis Patent Litigation

Is Synthon allowed to sell generic Eliquis immediately?

Not based solely on the filing or dismissal of the case. Synthon would need FDA approval and a legal basis for launch, such as patent expiration, a settlement license or a final judgment permitting entry.

Does a Paragraph IV certification mean the Eliquis patent is invalid?

No. It is the generic applicant's legal position that the patent is invalid, unenforceable or not infringed. The position must be tested through litigation or resolved through settlement.

Are Eliquis formulation patents stronger than the compound patent?

Usually, a compound patent provides broader protection. A formulation patent can remain valuable if its claims read on common generic products and survive validity and claim-construction challenges.

Is generic apixaban a biosimilar?

No. Apixaban is a chemically synthesized small-molecule drug. Generic apixaban is approved through the ANDA pathway, not the biosimilar pathway.

Can a generic launch after the main Eliquis patent expires but before all Orange Book patents expire?

Only if the remaining patents do not block the proposed product, the generic has a license, the patents are invalidated or the applicant accepts the legal risk of an at-risk launch.

References

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

2. Pfizer Inc. v. Synthon Pharmaceuticals, Inc., No. 1:22-cv-00045, U.S. District Court for the District of Delaware. (2022). Docket and pleadings.

3. U.S. Patent No. 6,967,208. (2005). Chemical compounds. U.S. Patent and Trademark Office.

4. U.S. Patent No. 9,326,945. (2016). Pharmaceutical compositions comprising apixaban. U.S. Patent and Trademark Office.

5. U.S. Food and Drug Administration. (2023). Drugs@FDA: FDA-approved drugs, Eliquis prescribing information. U.S. Department of Health and Human Services.