Last updated: February 17, 2026
This litigation concerns allegations of patent infringement regarding Pfizer’s blockbuster drug, Eliquis (apixaban). Mylan Pharmaceuticals Inc. (now Viatris Inc.) is the defendant, accused of infringing on Pfizer’s patents covering Eliquis. The core of the dispute centers on Mylan’s proposed generic versions of apixaban and Pfizer’s assertions that these generics infringe its patent rights.
What are the key patents at issue in this litigation?
The litigation involves several patents protecting Pfizer's apixaban, primarily focusing on U.S. Patent Nos. 7,071,209 and 8,846,710.
- U.S. Patent No. 7,071,209: This patent, titled "Process for the preparation of 1-(4-methoxyphenyl)-7-oxo-6-[4-(2-oxopiperidin-1-yl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide and its salts," was issued on July 4, 2006. It generally claims methods of preparing apixaban.
- U.S. Patent No. 8,846,710: This patent, titled "Apixaban process," was issued on September 30, 2014. It claims an improved process for manufacturing apixaban.
Pfizer also holds other patents related to apixaban's formulation and use, which could be implicated in broader patent strategies.
What is the history and current status of the litigation?
Pfizer initiated this lawsuit in the U.S. District Court for the District of Delaware on January 16, 2019.
- Initial Filings: Pfizer alleged that Mylan's ANDA for a generic version of apixaban infringed the '209 and '710 patents.
- Claim Construction: The court conducted a Markman hearing to determine the meaning of key patent claims. This process is crucial for defining the scope of the asserted patents. The court issued its Claim Construction Order on March 26, 2020, defining terms such as "substantially pure," "ambient temperature," and "about 10-20%."
- Summary Judgment: Both parties filed motions for summary judgment on issues of non-infringement and invalidity.
- Trial: A bench trial commenced on June 14, 2021, to resolve remaining disputes.
- District Court Ruling: On September 10, 2021, the District Court ruled that Mylan did not infringe the asserted claims of U.S. Patent No. 7,071,209. The court also found that Mylan did not infringe the asserted claims of U.S. Patent No. 8,846,710. The court specifically found that Mylan’s proposed manufacturing process for apixaban did not fall within the scope of the patent claims as construed.
- Appeal: Pfizer appealed the District Court's decision to the U.S. Court of Appeals for the Federal Circuit.
- Federal Circuit Ruling: On May 11, 2023, the Federal Circuit affirmed the District Court's judgment of non-infringement. The appellate court agreed with the lower court's interpretation of the patent claims and its finding that Mylan's process did not infringe.
Current Status: The litigation has concluded with a final judgment of non-infringement, affirmed by the Federal Circuit. This outcome permits Mylan (Viatris) to proceed with the launch of its generic apixaban product, subject to any other regulatory approvals.
What are Mylan's primary defenses?
Mylan's defenses in this litigation have primarily focused on non-infringement and invalidity.
- Non-Infringement: Mylan argued that its manufacturing process for apixaban does not meet the specific limitations of Pfizer's asserted patent claims. This involves dissecting the process steps and chemical intermediates to demonstrate a lack of literal infringement or infringement under the doctrine of equivalents.
- Invalidity: Mylan also challenged the validity of Pfizer's patents, likely on grounds such as obviousness or lack of enablement, although the non-infringement finding rendered these arguments secondary in the final judgment.
The District Court's finding of non-infringement was based on a detailed analysis of Mylan’s process as compared to the construed claims of the '209 and '710 patents. For instance, regarding the '209 patent, the court found Mylan’s process did not produce a product that contained a specific amount of residual starting materials or intermediates as required by the claim. For the '710 patent, the court determined Mylan’s process did not fall within the scope of the patent’s method claims.
What are the implications of this ruling for Pfizer and its Eliquis franchise?
The ruling has significant implications for Pfizer's revenue streams and market exclusivity for Eliquis.
- Loss of Exclusivity: The Federal Circuit's affirmation of non-infringement clears the path for Mylan (Viatris) and potentially other generic manufacturers to launch apixaban products. This will lead to price erosion and a reduction in Eliquis sales.
- Patent Expiration Timeline: Eliquis's primary patents are set to expire in the coming years. This litigation outcome accelerates the loss of market exclusivity by permitting earlier generic entry.
- Revenue Impact: Eliquis is a substantial revenue generator for Pfizer. The introduction of generic competition is projected to significantly reduce its sales. In 2022, Eliquis generated over $11.8 billion in worldwide sales for Pfizer.
Comparative Impact: For reference, similar patent litigation outcomes for other blockbuster drugs have historically resulted in immediate and substantial revenue declines for the originator company, often exceeding 50% within the first year of generic entry.
What is the projected market impact of generic apixaban entry?
The entry of generic apixaban is expected to dramatically alter the anticoagulant market.
- Price Reduction: Generic drugs are typically priced at a significant discount compared to their branded counterparts, often 50% to 80% lower. This will lead to substantial savings for healthcare systems and patients.
- Increased Accessibility: Lower prices will likely increase the accessibility of apixaban for patients who might have faced cost barriers with the branded product.
- Market Share Shift: Generic apixaban will capture a significant portion of the market share previously held by Eliquis. The speed and extent of this shift will depend on market dynamics, including the number of generic entrants and their pricing strategies.
Market Data Context: The global market for anticoagulants is substantial, driven by the high prevalence of conditions like atrial fibrillation and deep vein thrombosis. The introduction of generics for a leading drug like apixaban will reshape competitive landscapes.
What are the next steps or potential future legal challenges?
With the Federal Circuit's decision, the patent litigation phase of this specific dispute is largely concluded.
- Regulatory Approval: Mylan (Viatris) will proceed with its final FDA approval for its generic apixaban product, if not already obtained.
- Market Launch: Upon approval, Mylan can launch its generic product.
- Future Litigation: While this specific infringement case is settled, other patents related to apixaban (e.g., formulation, method of use) may exist and could be subject to future litigation if they remain unexpired and are asserted. However, the primary process patents forming the basis of this suit have been resolved in favor of non-infringement.
Key Takeaways
- Pfizer Inc. v. Mylan Pharmaceuticals Inc. concluded with the Federal Circuit affirming a District Court ruling of non-infringement against Pfizer's asserted patents for apixaban.
- The ruling permits Mylan (Viatris) to launch its generic apixaban product, accelerating the loss of market exclusivity for Pfizer's Eliquis.
- The primary patents at issue were U.S. Patent Nos. 7,071,209 and 8,846,710, both related to apixaban manufacturing processes.
- Generic apixaban entry is expected to lead to significant price reductions and increased market accessibility.
- Eliquis generated over $11.8 billion in worldwide sales in 2022, indicating a substantial financial impact from generic competition.
Frequently Asked Questions
-
When can Mylan (Viatris) launch its generic apixaban?
Mylan can launch its generic apixaban product upon receiving final FDA approval, following the conclusion of the patent litigation affirming non-infringement.
-
What is the market impact on Eliquis sales expected to be?
Eliquis sales are projected to decline substantially following the introduction of generic apixaban due to price erosion and market share shift.
-
Are there other patents protecting Eliquis that could lead to further litigation?
While this specific litigation addressed key process patents, other patents related to apixaban’s formulation or method of use may exist and could be subject to future legal challenges if still in force.
-
What is the significance of the Federal Circuit affirming the District Court's decision?
The Federal Circuit's affirmation means the non-infringement ruling is upheld, making it highly unlikely for Pfizer to pursue further appeals on these specific patent claims and clearing the path for generic entry.
-
What was the primary basis for the non-infringement ruling?
The courts found that Mylan's proposed manufacturing process for apixaban did not meet the specific limitations of Pfizer's asserted patent claims, as interpreted through the claim construction process.
Citations
[1] Pfizer Inc. v. Mylan Pharmaceuticals Inc., No. 1:19-cv-00097 (D. Del. Sept. 10, 2021).
[2] Pfizer Inc. v. Mylan Pharmaceuticals Inc., No. 2022-1068 (Fed. Cir. May 11, 2023).
[3] U.S. Patent No. 7,071,209. (2006).
[4] U.S. Patent No. 8,846,710. (2014).
[5] Pfizer Inc. (2023). Pfizer Reports Second Quarter 2023 Results. [Press release].
