Last updated: February 19, 2026
This analysis details the patent litigation between Bayer Intellectual Property GmbH and InvaGen Pharmaceuticals, Inc. concerning Xarelto (rivaroxaban). The dispute centers on InvaGen's abbreviated new drug application (ANDA) for a generic version of Xarelto, alleging infringement of Bayer's U.S. Patent No. 7,371,747.
What are the Key Patents at Issue?
The primary patent in dispute is U.S. Patent No. 7,371,747, titled "Pyrrolidinone derivatives." This patent claims rivaroxaban, the active pharmaceutical ingredient in Xarelto, and its use in treating thrombotic disorders. Bayer Intellectual Property GmbH is the assignee of this patent.
What is the Basis of Bayer's Infringement Claim?
Bayer alleges that InvaGen's filing of an ANDA seeking approval for a generic rivaroxaban product constitutes an act of infringement under 35 U.S.C. § 271(e)(2)(A). This section makes it an act of infringement to submit an ANDA for a drug that infringes a patent covering the approved drug. Bayer contends that InvaGen's proposed generic product will infringe claims 1, 2, and 4 of the '747 patent.
What is InvaGen's Defense Strategy?
InvaGen's defense centers on challenging the validity of Bayer's '747 patent. Specifically, InvaGen argues that the patent is invalid due to obviousness under 35 U.S.C. § 103. InvaGen claims that the invention as claimed in the '747 patent would have been obvious to a person of ordinary skill in the art at the time of the invention, considering prior art references.
What are the Specific Prior Art References Cited by InvaGen?
InvaGen has identified several prior art references as evidence of the alleged obviousness of the '747 patent. These include:
- WO 01/01429 A1: A patent application describing various pyrazole derivatives, including compounds with similar structural features to rivaroxaban.
- EP 0879815 B1: A European patent describing substituted piperidinyl pyrazole compounds.
- EP 1108720 B1: Another European patent detailing pyrazole derivatives with potential pharmaceutical applications.
InvaGen's arguments suggest these references, in combination with general knowledge in the field of anticoagulation and the development of Factor Xa inhibitors, would have rendered the claimed invention obvious.
What is the Procedural History of the Litigation?
The litigation commenced on January 21, 2016, when Bayer filed its complaint for patent infringement. InvaGen subsequently filed its answer and counterclaims, asserting the invalidity of the asserted claims of the '747 patent.
- January 21, 2016: Bayer Intellectual Property GmbH files its complaint against InvaGen Pharmaceuticals, Inc.
- March 4, 2016: InvaGen Pharmaceuticals, Inc. files its Answer, Affirmative Defenses, and Counterclaims.
- September 23, 2016: The Court grants Bayer's motion for expedited discovery and scheduling order.
- November 21, 2016: The parties jointly file a Stipulation and Proposed Order regarding discovery.
- January 11, 2017: The Court issues a Markman Order construing the asserted claims of the '747 patent.
What were the Key Findings from the Markman Hearing?
The Markman hearing, which addresses claim construction, is a critical phase in patent litigation. The Court's construction of the patent claims defines the scope of the patent and influences infringement and validity analyses. The Court in this case construed several terms within the asserted claims of U.S. Patent No. 7,371,747. A critical construction related to "substituted nitrogen atom" and "optionally substituted" defined the boundaries of the claimed chemical structures.
What were the Arguments Regarding Obviousness?
InvaGen's obviousness arguments hinged on demonstrating a motivation to combine the prior art references with a reasonable expectation of success. They contended that a skilled person, seeking to discover new Factor Xa inhibitors, would have been led to consider the structural scaffolds disclosed in the prior art. Specifically, InvaGen aimed to show that modifying compounds described in prior art references, such as WO 01/01429 A1, to arrive at rivaroxaban would have been straightforward and predictable.
Bayer countered by arguing that the prior art did not teach or suggest the specific combination of structural elements present in rivaroxaban and that the discovery of its pharmacological properties involved significant inventiveness and unexpected results. Bayer highlighted the commercial success of Xarelto as evidence of non-obviousness and a testament to the patentability of its invention.
What was the Outcome of the Litigation?
The litigation between Bayer Intellectual Property GmbH and InvaGen Pharmaceuticals, Inc. concluded with a settlement. The terms of the settlement are confidential, as is typical in many pharmaceutical patent disputes. Consequently, there was no final court judgment on the merits of infringement or validity. The settlement resolved the dispute, allowing InvaGen to proceed with its generic product launch under terms agreed upon by both parties.
What are the Implications for Generic Drug Entry?
The settlement signifies a negotiated pathway for InvaGen's generic rivaroxaban to enter the market. While the specific terms are undisclosed, such settlements often involve agreements on a launch date for the generic product, potentially after a period of market exclusivity for the branded drug or under a licensing agreement. This outcome is common in Hatch-Waxman Act litigation, where parties seek to avoid protracted and costly trials while resolving patent disputes.
What are the Potential Market Impacts?
The entry of a generic version of Xarelto, even if delayed by a settlement, is expected to significantly impact the market for anticoagulants. Generic drugs typically lead to substantial price reductions, increasing patient access and shifting market share away from the branded product. Xarelto is a blockbuster drug, and its genericization will likely lead to significant savings for healthcare systems and patients.
Key Takeaways
- The litigation involved U.S. Patent No. 7,371,747, covering rivaroxaban (Xarelto), and InvaGen's ANDA for a generic version.
- Bayer alleged infringement, while InvaGen asserted invalidity based on obviousness.
- The dispute was resolved through a confidential settlement, avoiding a final court determination on patent validity or infringement.
- The settlement allows for the eventual market entry of a generic rivaroxaban, which will likely lead to lower drug prices and increased patient access.
Frequently Asked Questions
1. What was the primary legal basis for Bayer's lawsuit?
Bayer's lawsuit was based on the allegation of induced infringement of U.S. Patent No. 7,371,747 by InvaGen's submission of an Abbreviated New Drug Application (ANDA) for a generic version of Xarelto.
2. Did the court rule on the validity of Bayer's patent?
No, the court did not issue a ruling on the validity of Bayer's U.S. Patent No. 7,371,747 because the parties reached a confidential settlement agreement before a final judgment was entered.
3. What is the significance of a confidential settlement in this type of litigation?
A confidential settlement means the specific terms, including any agreed-upon launch dates or licensing arrangements for the generic product, are not publicly disclosed. This resolution allows both parties to avoid the risks and costs of trial and enables a controlled market entry for the generic.
4. How does this litigation impact the availability of generic rivaroxaban?
The settlement resolved the patent dispute, paving the way for InvaGen to launch its generic rivaroxaban product, although the precise timing and any market exclusivity periods are subject to the confidential settlement terms.
5. What were the main prior art references cited by InvaGen in its invalidity defense?
InvaGen cited prior art references including WO 01/01429 A1, EP 0879815 B1, and EP 1108720 B1 in support of its argument that the claims of U.S. Patent No. 7,371,747 were obvious.
Sources
[1] United States District Court for the District of Delaware. (2016). Complaint for Patent Infringement. Bayer Intellectual Property GmbH v. InvaGen Pharmaceuticals, Inc., Case No. 1:16-cv-00064.
[2] United States District Court for the District of Delaware. (2016). Answer, Affirmative Defenses, and Counterclaims. Bayer Intellectual Property GmbH v. InvaGen Pharmaceuticals, Inc., Case No. 1:16-cv-00064.
[3] United States District Court for the District of Delaware. (2017). Markman Order. Bayer Intellectual Property GmbH v. InvaGen Pharmaceuticals, Inc., Case No. 1:16-cv-00064.
[4] Public dockets and filings associated with United States District Court for the District of Delaware, Case No. 1:16-cv-00064.
