Bayer & Janssen v. Ascent & Hetero: Rivaroxaban Patent Dispute Dismissed With Prejudice
Bayer AG, Bayer Pharma AG, and Janssen Pharmaceuticals brought a patent infringement action in the Delaware District Court against Ascent Pharmaceuticals and Hetero Labs over two patents covering rivaroxaban tablets. The case resolved in 173 days via a stipulated dismissal with prejudice, with all parties bearing their own costs.
ANDA Rivaroxaban Dispute Ends in Swift Bilateral Dismissal
Bayer AG, Bayer Pharma AG, and Janssen Pharmaceuticals, Inc. filed this patent infringement action on 16 May 2024 in the U.S. District Court for the District of Delaware before Judge Richard G. Andrews. The plaintiffs asserted two patents — US9539218B2 and US10828310B2 — against Ascent Pharmaceuticals, Inc. and Hetero Labs Limited, targeting Ascent’s proposed generic rivaroxaban tablets in 2.5 mg, 10 mg, 15 mg, and 20 mg dosage strengths. Rivaroxaban is the active ingredient in Xarelto, a blockbuster anticoagulant co-marketed by Bayer and Janssen.
The case closed on 5 November 2024, just 173 days after filing, through a joint stipulation of dismissal with prejudice under Federal Rules of Civil Procedure 41(a)(1) and 41(c). Both plaintiffs’ claims and defendants’ counterclaims were dismissed in their entirety. Critically, the dismissal was with prejudice on both sides, meaning neither party can relitigate the same claims arising from this action. Each party agreed to absorb its own legal costs, suggesting a negotiated resolution rather than a unilateral capitulation.
The 173-day resolution is notably rapid for Hatch-Waxman ANDA litigation, where cases routinely extend two to four years through trial. The bilateral nature of the dismissal — extinguishing both infringement claims and invalidity counterclaims — is consistent with a confidential settlement or licensing arrangement, though the public record does not disclose specific terms. The cost-bearing arrangement, in which each side absorbs its own fees, is a hallmark of negotiated exits rather than courtroom victories, suggesting the parties reached a commercial accommodation that the record does not fully reveal.
Filing to Dismissed with Prejudice in 173 days
173 days — resolved well under the median ANDA patent trial in Delaware
Dismissed with prejudice: what the bilateral stipulation means for both parties
Rule 41 stipulated dismissal — all claims extinguished permanently
Under FRCP 41(a)(1) and 41(c), the parties jointly stipulated to dismiss all claims and counterclaims with prejudice. A dismissal with prejudice is a final adjudication on the merits — neither Bayer/Janssen nor Ascent/Hetero can revive these specific claims in a future action. This is the functional equivalent of a final judgment, foreclosing relitigation of the infringement and invalidity issues raised in this case.
Permanent bar on relitigationPatents survive — no invalidity finding on the record
Because the dismissal is with prejudice before any merits ruling, Bayer and Janssen secure one critical outcome: neither US9539218B2 nor US10828310B2 was adjudicated invalid or unenforceable in this proceeding. The patents remain in force and can be asserted against other ANDA filers. However, the dismissal also forecloses any infringement judgment against Ascent, suggesting the parties reached a separate commercial arrangement outside the public record.
Patents intact, no invalidity rulingAscent avoids infringement finding — future market entry terms unclear
Ascent Pharmaceuticals and Hetero Labs exit this litigation without a court finding of infringement against them. Their invalidity counterclaims are also dismissed with prejudice, meaning they cannot relitigate those specific arguments in Delaware. Any commercial path to market for Ascent’s rivaroxaban tablets — whether through a license, authorised generic arrangement, or agreed launch date — would be governed by undisclosed private terms consistent with a settlement.
No infringement finding; counterclaims goneRapid resolution signals negotiated entry strategy for rivaroxaban generics
The 173-day timeline is atypically short for Hatch-Waxman ANDA litigation and strongly suggests a licensing or entry-date agreement was reached. For other ANDA filers and generic manufacturers watching the rivaroxaban landscape, the swift bilateral exit may signal that Bayer and Janssen are actively managing generic entry through negotiated arrangements rather than protracted litigation — a pattern that can affect the competitive dynamics and timing of the broader generic rivaroxaban market.
Likely licensed or agreed entryFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Bayer AG | Company | Pharmaceutical IP holders — co-owners of rivaroxaban tablet patents US9539218B2 and US10828310B2Search in Eureka ↗ |
| Co-Plaintiff | Janssen Pharmaceuticals, Inc. | Company | Search in Eureka ↗ |
| Co-Plaintiff | Bayer Pharma AG | Company | Search in Eureka ↗ |
| Co-Plaintiff | Bayer AG | Company | Search in Eureka ↗ |
| Defendant | Ascent Pharmaceuticals, Inc. | Company | Generic pharmaceutical manufacturer and API supplier facing ANDA infringement allegationsSearch in Eureka ↗ |
| Co-Defendant | Hetero Labs Limited | Individual | Search in Eureka ↗ |
| Plaintiff counsel | Derek James Fahnestock | Attorney | Counsel for Bayer AGSearch in Eureka ↗ |
| Plaintiff counsel | Jack B. Blumenfeld | Attorney | Counsel for Bayer AGSearch in Eureka ↗ |
| Plaintiff counsel | Rodger Dallery Smith , II | Attorney | Counsel for Bayer AGSearch in Eureka ↗ |
| Plaintiff law firm | Morris, Nichols, Arsht & Tunnell LLP | Law Firm | Representing Bayer AGSearch in Eureka ↗ |
| Defendant counsel | Cortlan S. Hitch | Attorney | Counsel for Ascent Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant law firm | Morris James LLP | Law Firm | Representing Ascent Pharmaceuticals, Inc.Search in Eureka ↗ |
| Presiding judge | Judge Richard G. Andrews | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulation explicitly invokes FRCP 41(a)(1) and 41(c), covering both the plaintiffs’ complaint and the defendants’ counterclaims, ensuring a fully bilateral and permanent resolution. The phrase ‘dismissed with prejudice’ carries significant legal weight: it bars both parties from reasserting these specific claims or defenses in any future proceeding. The cost-neutral fee arrangement — each party bearing its own costs — is characteristic of a negotiated commercial settlement rather than a contested court outcome, though no settlement terms are disclosed in the public record.
US9539218B2 & US10828310B2 — rivaroxaban tablet formulation patents
US9539218B2 (application number US11/883218) and US10828310B2 (application number US16/264032) relate to rivaroxaban tablet formulations — the active ingredient in Xarelto, a Factor Xa inhibitor used for stroke prevention, DVT, and pulmonary embolism treatment. These patents cover formulation and dosing aspects of rivaroxaban tablets across the commercially critical 2.5 mg, 10 mg, 15 mg, and 20 mg dosage strengths targeted by Ascent’s ANDA filing. Both patents are held by the Bayer/Janssen partnership that co-developed and co-commercialises Xarelto globally.
Rivaroxaban is one of the highest-revenue branded anticoagulants worldwide, making its patent estate a primary enforcement target for Bayer and Janssen. The two asserted patents represent successive layers of formulation protection — a common originator strategy to extend effective market exclusivity beyond the core compound patent. For generic manufacturers and API suppliers, the breadth of these formulation claims creates meaningful ANDA filing risk, particularly where dosage strength overlap with the 2.5 mg–20 mg commercial range is unavoidable. The absence of any invalidity ruling in this case leaves these patents at full strength for enforcement against subsequent filers.
Should you run an FTO against US9539218B2 and US10828310B2?
Any pharmaceutical company developing or commercialising generic rivaroxaban tablets — particularly in the 2.5 mg, 10 mg, 15 mg, or 20 mg strengths — should treat these two patents as primary FTO obstacles. API suppliers, contract development and manufacturing organisations (CDMOs), and ANDA filers sourcing rivaroxaban from third-party manufacturers face potential co-defendant exposure, as this case’s inclusion of Hetero Labs illustrates. An FTO analysis should assess both formulation claims and method-of-use claims across the full dosage range.
PatSnap Eureka’s FTO Search Agent can map the claim scope of US9539218B2 and US10828310B2 against your proposed formulation and dosage profile, identify prior art relevant to invalidity arguments, and surface related patents in Bayer and Janssen’s rivaroxaban estate that may present additional clearance issues. With no invalidity ruling on the record from this case, proactive FTO analysis is essential before any ANDA filing or commercial launch decision targeting the rivaroxaban market.
Run a freedom-to-operate analysis on US9539218B2 to assess your product’s exposure
Run FTO in Eureka →Similar rivaroxaban and ANDA patent cases in Delaware District Court
Explore related Hatch-Waxman ANDA infringement actions involving rivaroxaban tablet formulation patents litigated in the Delaware District Court.
What this case signals for the pharmaceutical patent IP landscape
This rapid ANDA dismissal offers pointed lessons for generic manufacturers, branded pharma IP teams, and FTO analysts tracking rivaroxaban patent exposure.
With-prejudice bilateral dismissals preserve patent validity for future ANDA challengers
Bayer and Janssen secured a dismissal that leaves both US9539218B2 and US10828310B2 unscathed on validity grounds. Any subsequent ANDA filer must contend with patents that have never been invalidated in court, raising the risk profile for future paragraph IV certification challenges against these specific patents.
173-day resolution suggests proactive licensing is Bayer/Janssen’s preferred playbook
The speed of resolution — well inside a typical Hatch-Waxman 30-month stay window — is consistent with originator-preferred negotiated entry strategies. Generic manufacturers and their investors should anticipate that Bayer and Janssen may seek early commercial resolution rather than full trial, shaping how future ANDA challengers price litigation risk for rivaroxaban.
Bayer v Ascent — key questions answered
Bayer and Janssen asserted two patents: US9539218B2 and US10828310B2. Both cover rivaroxaban tablet formulations and were asserted against Ascent’s proposed generic rivaroxaban tablets in 2.5 mg, 10 mg, 15 mg, and 20 mg dosage strengths in the Delaware District Court.
The case was dismissed with prejudice by joint stipulation under FRCP 41(a)(1) and 41(c). A with-prejudice dismissal permanently extinguishes all claims and counterclaims — neither party can relitigate these specific issues. It is the functional equivalent of a final judgment and is consistent with a negotiated settlement, though no terms are publicly disclosed.
No. The case was dismissed before any merits ruling. The court made no finding on validity or infringement. Both patents remain in force and have not been adjudicated invalid or unenforceable in this proceeding, leaving them available for enforcement against other ANDA filers.
Hetero Labs Limited was named as a co-defendant, consistent with its role as an API or formulation supplier to Ascent. In ANDA litigation, originator plaintiffs frequently name upstream manufacturers when the accused generic product relies on third-party API or manufacturing. The public record does not specify the precise basis for Hetero’s inclusion beyond its co-defendant status.
The 173-day resolution is well below the typical Hatch-Waxman ANDA litigation timeline of two to four years. This rapid exit, combined with the bilateral with-prejudice dismissal and cost-neutral fee arrangement, strongly suggests a negotiated licensing or market-entry agreement was reached. It signals that Bayer and Janssen may be managing rivaroxaban generic entry through commercial deals rather than prolonged litigation — a pattern relevant to other ANDA filers assessing their litigation and market-entry risk.
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