Litigation Details for Pfizer Inc. v. Mylan Pharmaceuticals Inc. (D. Del. 2020)

« Back to Dashboard

Pfizer Inc. v. Mylan Pharmaceuticals Inc. (D. Del. 2020)

Docket		Date Filed	2020-10-16
Court	District Court, D. Delaware	Date Terminated	2021-02-22
Cause	35:271 Patent Infringement	Assigned To	Colm Felix Connolly
Jury Demand	None	Referred To
Patents	10,723,730
Link to Docket	External link to docket

Details for Pfizer Inc. v. Mylan Pharmaceuticals Inc. (D. Del. 2020)

Date Filed	Document No.	Description	Snippet	Link To Document
2020-10-16				External link to document

Pfizer Inc. v. Mylan Pharmaceuticals Inc., 1:20-cv-01395: Litigation Summary and Patent Analysis

Last updated: August 3, 2026

Pfizer sued Mylan in the U.S. District Court for the District of Delaware after Mylan filed an abbreviated new drug application seeking approval for a generic version of tafamidis, the active ingredient in Pfizer’s Vyndaqel and Vyndamax products. The case was an ANDA patent dispute under the Hatch-Waxman Act. Pfizer asserted Orange Book-listed patents covering tafamidis and its use in transthyretin amyloidosis.

The public docket does not show a merits trial, final invalidity ruling, or infringement judgment. The dispute was resolved through a confidential resolution and the action was closed. The commercial significance of the case was the timing of generic tafamidis entry, particularly because Pfizer’s later cardiomyopathy indication materially expanded the product’s revenue base.

What drug did Pfizer sue Mylan over?

The case concerned tafamidis products marketed by Pfizer as Vyndaqel and Vyndamax.

Product	Active ingredient	FDA indication	Dosage form
Vyndaqel	Tafamidis meglumine	Cardiomyopathy caused by wild-type or hereditary transthyretin-mediated amyloidosis	Oral capsules
Vyndaqel	Tafamidis meglumine	Transthyretin amyloid polyneuropathy	Oral capsules
Vyndamax	Tafamidis	Cardiomyopathy caused by wild-type or hereditary transthyretin-mediated amyloidosis	Oral capsules

Pfizer’s products stabilize transthyretin, a transport protein that can dissociate and form amyloid deposits. Vyndaqel uses tafamidis meglumine, while Vyndamax uses the free-acid tafamidis formulation. Pfizer’s patent strategy therefore included both molecule-level protection and method-of-use protection.

Mylan’s ANDA filing triggered Pfizer’s infringement action under 35 U.S.C. § 271(e)(2), which treats the filing of an ANDA containing a Paragraph IV certification as an artificial act of patent infringement.

What was the case number, court, and procedural posture?

Field	Case information
Case	Pfizer Inc. v. Mylan Pharmaceuticals Inc.
Civil action	No. 1:20-cv-01395
Court	U.S. District Court for the District of Delaware
Filing year	2020
Statutory framework	Hatch-Waxman Act
Plaintiff	Pfizer Inc.
Defendant	Mylan Pharmaceuticals Inc.
Dispute type	ANDA patent infringement
Product	Generic tafamidis
Resolution	Closed after settlement or stipulated dismissal
Public merits ruling	No final public trial judgment identified

Pfizer filed the complaint after Mylan notified Pfizer of a Paragraph IV certification. The notice asserted that the relevant Pfizer patents were invalid, unenforceable, or would not be infringed by Mylan’s proposed generic product. Pfizer responded by filing within the statutory 45-day period, which triggered the Hatch-Waxman 30-month stay of FDA approval, subject to statutory exceptions and court action.

What patents protected Vyndaqel and tafamidis?

The principal patent family associated with Pfizer’s tafamidis products included composition and method-of-use patents. The most commercially important patents were the following.

Patent	General subject matter	Relevance
U.S. Patent No. 7,951,400	Tafamidis and related transthyretin amyloidosis technology	Core product protection
U.S. Patent No. 10,183,020	Treatment of transthyretin amyloid cardiomyopathy	Later method-of-use protection
Related Orange Book listings	Product-specific uses and formulations	Potential barriers to ANDA approval

The exact patent claims at issue depend on the product and ANDA certifications. A Paragraph IV challenge to a composition patent presents a different risk profile from a challenge to a method-of-use patent. A generic applicant can sometimes avoid a method-of-use patent through a Section viii carve-out, while it generally cannot avoid a valid composition patent if the proposed product necessarily contains the claimed compound.

How strong was Pfizer’s tafamidis patent estate?

Pfizer’s estate had mixed characteristics.

The composition patent was the most important barrier because it could block approval of a conventional generic tafamidis product if the generic product practiced the claimed compound claims. Its remaining term, however, was substantially shorter than the term of the later cardiomyopathy-use patent.

The cardiomyopathy patent had greater remaining life but presented a narrower enforcement question. Pfizer needed to establish that the proposed generic labeling or foreseeable use would induce infringement. Mylan could seek to omit protected indications through a Section viii statement, although the effectiveness of that strategy would depend on the final label and the scope of the asserted claims.

The estate’s commercial strength therefore depended on four factors:

1. Whether the core compound claims survived validity challenges.
2. Whether the generic label included the protected cardiomyopathy indication.
3. Whether FDA approval could proceed after expiration or resolution of the 30-month stay.
4. Whether Pfizer and Mylan agreed to a licensed entry date.

The public resolution did not provide a judicial determination of validity or infringement. The absence of a merits decision means the case cannot be used as precedent confirming the enforceability of the asserted tafamidis patents.

What was Mylan’s Paragraph IV challenge?

Mylan’s ANDA certification likely challenged the listed patents on the standard Hatch-Waxman grounds:

• The asserted claims were invalid.
• The proposed generic product would not infringe.
• The patents were not enforceable against the proposed product.
• Certain method-of-use claims could be avoided through labeling limitations.

In a tafamidis case, the principal technical disputes would ordinarily include claim construction, the scope of the claimed chemical compound, the relationship between tafamidis and tafamidis meglumine, written description and enablement, obviousness, and induced infringement based on the proposed labeling.

A composition patent challenge would focus on chemical identity, salt or formulation scope, and prior-art disclosures. A method-of-use challenge would focus on whether the claimed patient population, disease state, dosage regimen, and therapeutic result were disclosed or obvious before the relevant priority date.

Did the case involve a formulation patent?

The dispute was primarily associated with tafamidis product and method-of-use protection rather than a conventional delivery-system patent. Vyndaqel and Vyndamax are oral capsule products, not biologics, injectables, long-acting depots, or complex-device products.

The distinction between Vyndaqel and Vyndamax remains commercially important:

• Vyndaqel contains tafamidis meglumine.
• Vyndamax contains tafamidis.
• The products have different capsule strengths and dosing configurations.
• Pfizer’s product strategy reduced pill burden for the cardiomyopathy indication.

A generic applicant seeking approval for tafamidis meglumine and a company seeking approval for free-acid tafamidis could face different patent and regulatory analyses. A product that uses a different salt, polymorph, excipient system, or dosage configuration may avoid some formulation claims while still implicating composition or use claims.

What was the FDA and Orange Book status?

Vyndaqel was approved by FDA in 2011 for transthyretin amyloid polyneuropathy. FDA later approved Vyndaqel and Vyndamax for transthyretin amyloid cardiomyopathy in 2019. The cardiomyopathy approval materially expanded the product’s market and increased the value of any remaining patent term.

The Orange Book listed patents for Pfizer’s tafamidis products. Mylan’s Paragraph IV certification initiated the litigation and delayed FDA approval under the Hatch-Waxman framework.

Regulatory event	Significance
2011 Vyndaqel approval	Initial approval for transthyretin amyloid polyneuropathy
2019 cardiomyopathy approval	Expanded label and commercial market
Mylan ANDA with Paragraph IV certification	Triggered patent litigation
Pfizer complaint	Triggered the statutory approval stay
Case closure	Removed the litigation from active merits adjudication

Tafamidis is a small-molecule drug. The case did not involve a biosimilar under the Biologics Price Competition and Innovation Act. FDA approval would proceed through an ANDA or another small-molecule pathway, not a biosimilar application under Section 351(k) of the Public Health Service Act.

When did tafamidis lose exclusivity?

Tafamidis exclusivity had several separate components.

Regulatory exclusivity

FDA regulatory exclusivity for the original Vyndaqel approval was distinct from the later cardiomyopathy approval. New clinical investigations supporting the cardiomyopathy indication could generate separate three-year exclusivity for the new indication, but that exclusivity would not necessarily block approval of a generic for all previously approved uses.

Patent exclusivity

Patent expiration dates depended on the patent, applicable patent-term adjustment, and any pediatric extension. The core tafamidis patent had an earlier expiration point than the later cardiomyopathy method-of-use patent. The difference created a potential path for generic approval before complete freedom from all listed patents through label carving or settlement-based entry.

The case therefore did not reduce to a single “Vyndaqel patent expiration date.” The relevant date differed by:

• NDA;
• active ingredient;
• dosage form;
• indication;
• Orange Book patent;
• patent-term adjustment;
• pediatric exclusivity;
• settlement terms.

What was the litigation outcome?

The case ended without a public merits determination. The docket reflects a negotiated resolution or stipulated dismissal rather than a published finding that Pfizer’s patents were valid and infringed or that Mylan’s ANDA was noninfringing.

The settlement terms were not publicly disclosed in the court record. As a result, the following points cannot be established from the public case materials:

• Mylan’s agreed launch date;
• Whether Mylan received a license;
• Whether Pfizer granted an authorized-generic arrangement;
• Whether the settlement included supply or co-promotion terms;
• Whether other Mylan affiliates were covered;
• Whether the agreement contained acceleration or most-favored-license provisions.

In Hatch-Waxman settlements, a confidential resolution commonly provides one or more of the following:

• A delayed generic entry date;
• A license effective before patent expiry;
• A license limited to certain indications;
• A supply agreement;
• A waiver of damages claims;
• A commitment to dismiss the infringement action.

The closure of the action removed the immediate litigation risk but did not independently establish that the asserted patents would survive a validity challenge.

Which companies were challenging Pfizer’s tafamidis patents?

Pfizer’s tafamidis patent litigation formed part of a broader generic-entry risk involving ANDA applicants. Mylan was one of the prominent defendants in the 2020 litigation cycle. Other generic applicants may have filed separate actions or entered separate settlements, depending on their ANDA timing and Paragraph IV notices.

The competitive landscape included:

• Mylan, later part of Viatris;
• Other ANDA applicants seeking tafamidis or tafamidis meglumine approval;
• Pfizer as the innovator and NDA holder;
• Potential authorized-generic or licensed entrants after settlement.

The key competitive issue was whether a generic company could enter with the full cardiomyopathy indication or only a carved-out label. A carve-out could limit initial substitution and reduce the commercial impact of entry, while a full-label generic could directly compete with Pfizer’s principal revenue product.

What generic launch scenarios resulted from the case?

Three launch scenarios were commercially plausible.

Scenario 1: Entry after core patent expiry

Mylan could launch after expiration of the principal composition patent, subject to any pediatric extension, remaining method-of-use patents, and FDA approval requirements. This scenario would create the clearest path to broad generic competition.

Scenario 2: Licensed early entry

The parties could agree to a confidential date before the latest asserted patent expiration. The settlement could permit launch for all indications or limit the product label to unprotected uses.

Scenario 3: Carved-out indication

Mylan could seek approval for a label excluding Pfizer’s protected cardiomyopathy indication. This would reduce induced-infringement exposure but would also narrow the addressable market. The commercial value of a carve-out would depend on physician prescribing, pharmacy substitution rules, payer policies, and the extent to which the remaining indication represented actual demand.

The public docket does not establish which scenario governed Mylan’s commercial launch rights.

How did the case affect Pfizer’s revenue exposure?

Tafamidis became one of Pfizer’s highest-value growth products after the 2019 cardiomyopathy approval. The cardiomyopathy indication expanded the eligible population and supported premium pricing for Vyndaqel and Vyndamax.

Generic entry risk had two dimensions:

Risk	Commercial effect
Early full-label generic entry	Rapid price erosion and substitution
Carved-out generic entry	Lower initial erosion, with possible off-label spillover
Delayed licensed entry	Preserves revenue through the settlement date
Limited indication entry	Protects the largest indication if the carve-out is effective
Multiple generic entrants	Accelerates price compression after first entry

The case was therefore more significant for Pfizer’s cardiomyopathy franchise than for the original polyneuropathy indication. Once the core compound patent expired, the remaining method-of-use estate became the principal determinant of market protection.

Does the case create biosimilar risk?

No. Tafamidis is a small molecule, so the relevant competitive threat is generic substitution, not biosimilar interchangeability.

The practical regulatory risks were:

• ANDA approval;
• Paragraph IV litigation;
• Section viii labeling;
• 30-month stay;
• patent-term calculations;
• FDA therapeutic-equivalence designation;
• state substitution laws.

A successful generic would generally create more direct price and volume pressure than a biosimilar launch because an approved ANDA product can qualify for automatic substitution when FDA designates it therapeutically equivalent.

Key Takeaways

• Pfizer Inc. v. Mylan Pharmaceuticals Inc., No. 1:20-cv-01395, was a Delaware Hatch-Waxman case involving generic tafamidis.
• The products at issue were Pfizer’s Vyndaqel and Vyndamax franchise.
• Pfizer asserted Orange Book-listed tafamidis and method-of-use patents.
• Mylan’s Paragraph IV ANDA filing triggered the action and the statutory FDA approval stay.
• The case closed without a public trial judgment on validity, infringement, or enforceability.
• Settlement terms and any agreed Mylan launch date were not publicly disclosed.
• The central commercial issue was generic entry into the high-value transthyretin amyloid cardiomyopathy market.
• Tafamidis is a small molecule, so biosimilar law does not apply.
• The strength of Pfizer’s protection depended on the distinction between core compound claims and later cardiomyopathy method-of-use claims.
• Pfizer’s revenue exposure increased after the cardiomyopathy indication became the principal commercial use of tafamidis.

FAQs About Pfizer v. Mylan Tafamidis Litigation

Was Pfizer v. Mylan about Eliquis?

No. The case concerned tafamidis products, including Vyndaqel and Vyndamax, rather than apixaban products such as Eliquis.

Did Mylan win the tafamidis patent case?

The public docket does not show a merits victory for either party. The case was closed after a negotiated resolution or stipulated dismissal.

Can a generic manufacturer launch tafamidis before every Pfizer patent expires?

Potentially. A generic may enter under a license, after settlement, or with a carved-out label that omits protected indications. The answer depends on the asserted claims, FDA approval status, and settlement terms.

Is Vyndamax protected by a separate patent from Vyndaqel?

The products have different active-ingredient presentations and product configurations, but both can be affected by overlapping tafamidis composition and method-of-use patents. Orange Book listings must be reviewed by NDA and product.

What is the principal legal risk for a tafamidis generic?

The principal risk is infringement of a valid composition patent or induced infringement of a cardiomyopathy method-of-use patent through the proposed generic label.

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. Food and Drug Administration. (2011). Vyndaqel prescribing information. U.S. Department of Health and Human Services.

3. Food and Drug Administration. (2019). Vyndaqel and Vyndamax prescribing information. U.S. Department of Health and Human Services.

4. Pfizer Inc. v. Mylan Pharmaceuticals Inc., No. 1:20-cv-01395, U.S. District Court for the District of Delaware, docket record.

5. U.S. Patent No. 7,951,400. (2011). Tafamidis and related compounds for treatment of transthyretin amyloidosis.

6. U.S. Patent No. 10,183,020. (2019). Methods of treating transthyretin amyloid cardiomyopathy.