Last updated: August 15, 2026
Pfizer Inc. and Bristol-Myers Squibb challenged Mylan’s abbreviated new drug application for generic Eliquis (apixaban) in the U.S. District Court for the District of Delaware. The case was an Hatch-Waxman action under 35 U.S.C. § 271(e)(2), centered on U.S. Patent No. 6,967,208, the principal composition patent protecting apixaban. The litigation ended without a public merits judgment invalidating the patent. Mylan’s generic launch remained constrained by the patent and associated regulatory exclusivity, subject to the terms of the parties’ resolution and later Eliquis patent settlements. [1][2]
What drug and patents were involved in Pfizer v. Mylan, 1:15-cv-00026?
The action concerned Eliquis, the brand name for apixaban, an oral factor Xa inhibitor marketed in the United States by Bristol-Myers Squibb and Pfizer.
| Item |
Detail |
| Case |
Pfizer Inc. v. Mylan Laboratories Limited |
| Civil action |
No. 1:15-cv-00026 |
| Court |
U.S. District Court for the District of Delaware |
| Action type |
Hatch-Waxman patent infringement action |
| Product |
Eliquis, apixaban tablets |
| Reference NDA |
NDA 202155 |
| Generic filing |
Mylan ANDA for apixaban tablets |
| Principal patent |
U.S. Patent No. 6,967,208 |
| Statutory basis |
35 U.S.C. § 271(e)(2) |
| Commercial issue |
Whether Mylan could launch generic apixaban before expiration of Pfizer and Bristol-Myers Squibb patent rights |
The case is part of the broader Eliquis generic litigation involving multiple ANDA filers. The drug is approved for reduction of stroke and systemic embolism risk in nonvalvular atrial fibrillation and for treatment and prevention of deep-vein thrombosis and pulmonary embolism. [3]
What does U.S. Patent No. 6,967,208 cover?
U.S. Patent No. 6,967,208 covers apixaban compounds and related pharmaceutical compositions. The patent issued on Nov. 22, 2005, and was listed in the FDA Orange Book for Eliquis. Its claims provided the primary patent barrier to generic apixaban during the first wave of ANDA litigation. [2][4]
The patent’s ordinary term extended into 2026. FDA pediatric exclusivity, if applicable to the listed product and patent combination, can extend the effective regulatory barrier by six months. Orange Book dates and FDA exclusivity records control the operative launch analysis and should be read together with the patent file and any settlement restrictions. [2]
When does Eliquis lose exclusivity?
Eliquis has more than one form of protection. Patent expiry, pediatric exclusivity, regulatory exclusivity, and settlement-based launch restrictions must be analyzed separately.
| Protection |
Relevance |
| U.S. Patent No. 6,967,208 |
Core apixaban patent; ordinary term extends into 2026 |
| Pediatric exclusivity |
May add six months to eligible patent or regulatory protections |
| Orange Book-listed patents |
Can support additional Paragraph IV litigation if listed before ANDA approval |
| Newer formulation or method patents |
May create later litigation exposure but do not necessarily block approval of every ANDA |
| Settlement agreements |
May impose a contractual launch date different from the earliest theoretical patent date |
The commercially relevant generic-entry window is therefore not determined solely by the expiration date of U.S. Patent No. 6,967,208. The FDA must resolve any applicable 30-month stay, first-applicant exclusivity, pediatric extension, and unexpired Orange Book-listed claims.
What was Mylan’s Paragraph IV challenge?
Mylan’s ANDA included a patent certification challenging the Eliquis patent position. A Paragraph IV certification states that a listed patent is invalid, unenforceable, or will not be infringed by the proposed generic product.
Pfizer’s lawsuit was triggered under the Hatch-Waxman framework. Filing an infringement action within 45 days of receiving a Paragraph IV notice generally creates an automatic 30-month stay of FDA approval, subject to earlier termination or modification by court order. The action therefore had two commercial consequences:
- It delayed final FDA approval of Mylan’s ANDA during the statutory stay.
- It forced Mylan to litigate patent validity and infringement before commercial launch.
The case was not a conventional post-launch patent dispute. Mylan’s product had not entered the market, and the dispute focused on whether the proposed ANDA product would infringe the listed Eliquis patent.
Did Mylan challenge validity or only infringement?
The litigation presented the standard Paragraph IV issues of infringement, validity, and enforceability. In related Eliquis proceedings, generic defendants challenged the apixaban patent estate through obviousness and related validity theories. The Delaware court’s Eliquis rulings did not produce a broad public invalidation of the core apixaban patent. [1]
For Mylan, the practical result was that the company did not obtain an unrestricted early launch based on a final judgment defeating the principal patent. The case was resolved rather than completed through a publicly reported trial judgment against Pfizer.
What was the litigation timeline?
| Date or period |
Event |
| Jan. 12, 2015 |
Pfizer action filed in the District of Delaware |
| 2015 |
Mylan’s ANDA and Paragraph IV challenge placed the Eliquis patent estate in dispute |
| 2015-2017 |
Claim-construction, discovery, and coordinated litigation activity involving Eliquis ANDA defendants |
| 2017 onward |
Related courts addressed validity and infringement issues involving the core apixaban patent |
| Resolution period |
Pfizer, Bristol-Myers Squibb, and Mylan resolved the dispute without a public merits judgment invalidating the core patent |
| 2026 |
Ordinary term of the principal apixaban patent reaches its scheduled expiration period |
| 2026-2027 |
Potential generic-entry period depends on pediatric exclusivity, remaining Orange Book patents, FDA approval, and settlement terms |
The docket should be distinguished from later Eliquis antitrust and patent cases. A docket-level dismissal or settlement termination does not mean the underlying patent was judicially invalidated.
What was the litigation outcome?
The case ended without a publicly reported final decision holding U.S. Patent No. 6,967,208 invalid in the Mylan action. The commercial outcome was a negotiated resolution or dismissal rather than an unrestricted Mylan launch following a successful invalidity judgment.
That distinction matters for patent-risk analysis:
- Pfizer and Bristol-Myers Squibb retained the benefit of the core patent position.
- Mylan avoided the cost and risk of a full patent trial.
- Mylan’s launch rights depended on the settlement framework, patent expiry, FDA approval, and any later-listed patents.
- The resolution did not eliminate the possibility of later litigation over additional Eliquis patents or product-specific claims.
Public summaries of pharmaceutical settlements often report a permitted launch date without disclosing every commercial term. A launch license does not establish that the challenged patent was weak. It reflects the parties’ allocation of litigation, regulatory, and market-entry risk.
What is the Orange Book status of Eliquis?
Eliquis is an approved small-molecule drug listed in the FDA Orange Book. Unlike a biologic, it is subject to the ANDA pathway and Orange Book patent-certification rules.
Orange Book significance
An Orange Book listing can require a generic applicant to submit one of four certifications:
- Paragraph I: no patent information has been submitted.
- Paragraph II: the patent has expired.
- Paragraph III: the applicant will wait until patent expiration.
- Paragraph IV: the patent is invalid, unenforceable, or not infringed.
The Eliquis litigation arose from the Paragraph IV pathway. The relevant analysis includes the patent number listed against NDA 202155, the scope of the approved indication, the generic label, and whether the proposed product’s labeling induces infringement of any method-of-use claims.
The Orange Book is not a complete inventory of every patent that may affect commercial risk. It does not replace review of continuation patents, process patents, device rights, trade secrets, contractual restrictions, or litigation settlements.
What formulation and method-of-use patents protect Eliquis?
The core dispute in this case involved apixaban itself. Later Eliquis protection may include formulation, dosage, treatment-method, and manufacturing-related rights.
Formulation patents
Formulation claims can cover:
- Apixaban tablets containing specified excipients.
- Release, dissolution, or stability characteristics.
- Specific drug-to-excipient ratios.
- Manufacturing processes that produce a defined solid form or particle profile.
A formulation patent may not block every generic product. Its practical effect depends on whether the ANDA product uses the claimed formulation and whether the patent is listed for the reference product.
Method-of-use patents
Method-of-use patents may cover:
- A dosage regimen.
- Treatment of a defined patient population.
- Reduction of stroke or systemic embolism risk.
- Prevention or treatment of venous thromboembolism.
- Use after surgery or in a particular clinical setting.
Generic applicants can use a section viii “skinny label” to omit patented indications from labeling when the FDA permits the omission. That strategy does not eliminate infringement risk if the remaining label, promotional activity, or prescribing environment supports induced infringement.
Which companies challenged Eliquis patents?
Eliquis patent litigation involved multiple generic manufacturers, not only Mylan. Publicly reported defendants and challengers included major ANDA applicants such as Teva, Mylan, Apotex, and other generic drug companies. The cases were coordinated in Delaware and involved overlapping questions concerning apixaban patent validity and infringement. [1]
The competitive implications were substantial because generic entry by one approved applicant could rapidly reduce net pricing. Multiple successful Paragraph IV challengers would increase the probability of an accelerated price decline, while settlements could stagger or delay entry.
How strong was Pfizer’s Eliquis patent estate?
The estate was commercially strong against early generic entry but less secure after the 2026 core patent expiration period.
| Strength factor |
Assessment |
| Core composition patent |
Strongest barrier; supported by Orange Book listing and litigation |
| Litigation record |
No Mylan merits judgment publicly invalidating the core patent |
| ANDA exposure |
High because multiple generic companies challenged the same product |
| Secondary patents |
Potentially valuable but narrower and more vulnerable to non-infringement positions |
| Formulation protection |
Depends on the specific generic formulation and listed claim scope |
| Method-of-use protection |
Vulnerable to skinny-label strategies and indication-specific analysis |
| Manufacturing protection |
Can constrain supply chains but may not block all finished-dose manufacturers |
| Post-expiry position |
Substantially weaker once core composition rights and regulatory barriers lapse |
The most important weakness was concentration around a finite patent-expiry horizon. Eliquis did not have biologic-style interchangeability barriers or manufacturing complexity comparable to a monoclonal antibody. Once a lawful generic pathway opened, substitution and price competition could accelerate.
What generic launch risks existed for Mylan?
Mylan faced four principal risks.
1. Invalidity risk
If the court upheld the core patent, Mylan could not launch before the patent barrier expired without risking substantial damages and injunctive relief.
2. Infringement risk
A generic product may infringe composition or formulation claims even if its label differs from the brand label. A Paragraph IV defense therefore requires product-specific claim analysis.
3. Regulatory delay
The 30-month stay delayed FDA approval unless the court ended the stay earlier. Approval timing also depended on the first-filer position and any shared exclusivity.
4. Settlement restrictions
A settlement could provide an authorized or licensed launch date later than the earliest date suggested by a patent-expiry calculation. It could also include acceleration provisions, forfeiture conditions, or restrictions tied to other defendants’ launches.
Did the case involve biosimilar risk?
No. Eliquis is a chemically synthesized small molecule, not a biologic. Mylan’s product would proceed through an ANDA, not a biosimilar application under the Public Health Service Act.
The relevant competitive threats were:
- Abbreviated new drug applications.
- Paragraph IV certifications.
- 180-day generic exclusivity.
- Brand-generic settlement terms.
- Formulation and method-of-use patent litigation.
Biosimilar concepts such as interchangeability, reference-product exclusivity under the biologics statute, and patent dance procedures do not govern this case.
What revenue exposure did the litigation create?
Eliquis became one of Pfizer’s and Bristol-Myers Squibb’s largest products. Generic entry risk affected both companies’ alliance economics and global anticoagulant revenue.
The exposure profile had three stages:
- Pre-entry: high price and market share, with litigation costs and settlement leverage.
- Initial generic entry: rapid erosion risk, especially if multiple ANDA applicants launch concurrently.
- Post-entry: lower net pricing, reduced brand volume, and possible retention of patients through adherence, contracting, and indication breadth.
The case itself did not determine the full revenue trajectory. It addressed one ANDA applicant and one litigation pathway within a broader patent and settlement strategy.
What is the current legal significance of Pfizer v. Mylan?
The case is significant as an early Eliquis Paragraph IV action. It established the litigation context for Mylan’s attempted generic entry and preserved the commercial value of the core apixaban patent through negotiated resolution rather than an adverse invalidity ruling.
For diligence purposes, the case should be read with:
- FDA Orange Book records for NDA 202155.
- The complete prosecution history for U.S. Patent No. 6,967,208.
- Related Delaware Eliquis opinions.
- Any publicly filed settlement or dismissal papers.
- Later patent listings and continuation patents.
- FDA approval and exclusivity data for generic apixaban.
Key Takeaways
- Pfizer v. Mylan, No. 1:15-cv-00026, was an Eliquis apixaban Hatch-Waxman case.
- The principal patent issue involved U.S. Patent No. 6,967,208.
- Mylan challenged Pfizer and Bristol-Myers Squibb through the Paragraph IV ANDA process.
- The case ended without a public merits judgment invalidating the core patent.
- Eliquis is regulated as a small-molecule drug, so generic, not biosimilar, competition is the relevant risk.
- Generic entry depends on patent expiry, pediatric exclusivity, Orange Book listings, FDA approval, and settlement restrictions.
- Secondary formulation and method-of-use patents may affect timing but do not necessarily preserve the same market barrier as the core composition patent.
FAQs
What was Mylan’s proposed generic product in the case?
Mylan sought approval for generic apixaban tablets corresponding to Eliquis, Pfizer and Bristol-Myers Squibb’s branded factor Xa inhibitor.
Was Pfizer v. Mylan a patent trial?
It was a Hatch-Waxman patent infringement action, but the Mylan docket did not produce a publicly reported final merits judgment invalidating the principal Eliquis patent.
Can a generic company launch apixaban after the core patent expires?
Yes, if FDA approval is in place and no unexpired patent, pediatric exclusivity period, injunction, or settlement restriction prevents launch.
Does an Eliquis method-of-use patent block all generic apixaban sales?
No. The effect depends on the claim scope, the approved generic label, the omitted indications, and potential induced-infringement theories.
Why is the case number important in Eliquis patent research?
The case number identifies one Mylan proceeding within a larger group of Eliquis ANDA cases. Patent, settlement, and judgment conclusions from another defendant’s docket should not be attributed automatically to Mylan.
References
-
U.S. District Court for the District of Delaware. (2015). Pfizer Inc. v. Mylan Laboratories Limited et al., No. 1:15-cv-00026. PACER/CourtListener docket materials.
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U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
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U.S. Food and Drug Administration. (2012). Eliquis (apixaban) prescribing information. FDA, NDA 202155.
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United States Patent and Trademark Office. (2005). U.S. Patent No. 6,967,208: Novel compounds. USPTO.
