Esperion Therapeutics v. Hetero USA — NEXLETOL Patent Dispute Dismissed Without Prejudice
Esperion Therapeutics filed suit against Hetero USA, Hetero Labs Limited, and Honour Lab Limited in the District of New Jersey, asserting three patents covering bempedoic acid (NEXLETOL®), an ACL inhibitor for LDL cholesterol management. After 377 days, all claims and counterclaims between these parties were dismissed without prejudice by stipulation under Fed. R. Civ. P. 41(a)(1)(A)(ii), with each side bearing its own costs — while the broader consolidated action remains pending.
Stipulated exit: Esperion and Hetero part without a merits ruling on bempedoic acid IP
On 23 May 2024, Esperion Therapeutics, Inc. filed a patent infringement action in the U.S. District Court for the District of New Jersey against Hetero USA, Inc., Hetero Labs Limited, Hetero Labs Limited Unit V, and Honour Lab Limited, collectively the Hetero Defendants. The suit asserted three patents — US11760714B2, US7335799B2, and US11613511B2 — covering bempedoic acid and its ACL-inhibiting mechanisms, the active ingredient in Esperion’s branded cardiovascular drug NEXLETOL®.
The case was closed on 4 June 2025 via a stipulated dismissal filed under Fed. R. Civ. P. 41(a)(1)(A)(ii), with all claims and counterclaims between Esperion and the Hetero Defendants dismissed without prejudice. Crucially, each party agreed to bear its own costs, fees, and expenses. The dismissal was consolidated into a broader action at C.A. No. 24-05921, and the stipulation explicitly preserves all claims by Esperion against remaining defendants in that consolidated proceeding.
The 377-day duration before dismissal — without any merits ruling — is consistent with ANDA-related Hatch-Waxman litigation patterns where early commercial resolution or a negotiated licensing arrangement is possible but not publicly confirmed. The without-prejudice designation means Esperion could refile against Hetero on the same three patents; the public record does not disclose whether a confidential settlement, licensing deal, or strategic deferral drove the stipulation. The ongoing consolidated action against other defendants signals Esperion continues to actively enforce its bempedoic acid IP portfolio.
Filing to Dismissed without Prejudice in 377 days
377 days — above the median for ANDA-related pharmaceutical dismissals in D.N.J.
Dismissed without prejudice: what the stipulated exit means for both parties
Rule 41(a)(1)(A)(ii) — stipulated dismissal without court order
A dismissal under Fed. R. Civ. P. 41(a)(1)(A)(ii) is a voluntary, bilateral exit: both parties sign a stipulation and the case closes without any judicial ruling on the merits. The court has no discretion to reject it once properly filed. No findings of fact, no claim construction, and no validity or infringement determination are made — the three bempedoic acid patents remain fully intact and unchallenged on the record.
No merits adjudicationEsperion keeps its options open against Hetero on all three patents
A without-prejudice dismissal means Esperion is not barred from refiling the same infringement claims against the Hetero Defendants on US11760714B2, US7335799B2, or US11613511B2 if circumstances warrant. This contrasts sharply with a with-prejudice dismissal, which would function as a final adjudication. The public record does not disclose whether a licensing agreement or other arrangement underlies the stipulation — that question cannot be resolved from the docket alone.
Refile right preservedHetero exits this case, but no invalidity finding protects future ANDA launches
The Hetero Defendants secured dismissal without any adverse finding on infringement or validity. However, because the dismissal is without prejudice and the patents are unchallenged, Hetero has not established a legal basis for a commercial launch of a generic bempedoic acid product free of litigation risk. Any future ANDA approval or market entry could trigger a new infringement action. Hetero also bears its own legal costs, suggesting no cost-shifting leverage was obtained.
No invalidity shield securedConsolidated action continues — bempedoic acid patent enforcement is ongoing
The stipulation explicitly states that all claims against other defendants in the consolidated action at C.A. No. 24-05921 remain pending. This signals that Esperion’s enforcement strategy for NEXLETOL® IP is active and selective rather than concluded. Generic manufacturers outside the Hetero group remain under active litigation pressure. The three asserted patents — spanning bempedoic acid composition and ACL-inhibition methods — continue to represent a meaningful barrier to generic entry in the cardiovascular lipid-management market.
Broader enforcement ongoingFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Esperion Therapeutics, Inc. | Company | Cardiovascular biopharmaceutical company — holder of US11760714B2, US7335799B2, and US11613511B2Search in Eureka ↗ |
| Defendant | Hetero USA, Inc. | Company | Generic pharmaceutical manufacturer (Hetero USA, Hetero Labs, Honour Lab) seeking ANDA approvalSearch in Eureka ↗ |
| Co-Defendant | HONOUR LAB LIMITED | Individual | Search in Eureka ↗ |
| Co-Defendant | Hetero Labs Limited | Individual | Search in Eureka ↗ |
| Co-Defendant | Hetero Labs Limited | Individual | Search in Eureka ↗ |
| Plaintiff counsel | Jessica K. Formichella | Attorney | Counsel for Esperion Therapeutics, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Katelyn O’Reilly | Attorney | Counsel for Esperion Therapeutics, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Liza M. Walsh | Attorney | Counsel for Esperion Therapeutics, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Walsh Pizzi O’Reilly Falanga LLP | Law Firm | Representing Esperion Therapeutics, Inc.Search in Eureka ↗ |
| Defendant counsel | Jakob Benjamin Halpern | Attorney | Counsel for Hetero USA, Inc.Search in Eureka ↗ |
| Defendant law firm | Saiber LLC | Law Firm | Representing Hetero USA, Inc.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | New Jersey District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulation’s language is precise and consequential: claims are dismissed ‘without prejudice,’ preserving Esperion’s right to refile, while the cost-neutrality clause (‘each party to bear its own costs’) indicates neither side extracted a fee-shifting concession. The explicit carve-out — ‘All other claims… in the consolidated actions remain pending’ — is a deliberate drafting choice confirming this is a targeted bilateral exit, not a global resolution of the NEXLETOL® patent dispute. No infringement or invalidity finding was made on any of the three asserted patents.
US11760714B2, US7335799B2 & US11613511B2 — bempedoic acid ACL inhibitor patents
The three asserted patents cover different aspects of the bempedoic acid franchise. US7335799B2, with a 2003 application date, represents the foundational compound chemistry underlying NEXLETOL®. US11760714B2 and US11613511B2, both filed in 2022, extend protection into formulation and method-of-use territory. Collectively, they protect the ACL-inhibiting mechanism by which bempedoic acid reduces hepatic cholesterol synthesis — a non-statin approach to LDL reduction that gained FDA approval for patients unable to tolerate statins.
This layered portfolio architecture — an anchor compound patent supplemented by later formulation and method patents — is strategically significant because it allows Esperion to maintain Hatch-Waxman 30-month stays and litigation leverage across multiple ANDA filers through staggered expiry dates. The two 2022-filed patents in particular extend beyond the lead compound’s original exclusivity window. Any manufacturer seeking to launch a generic bempedoic acid product must contend with all three patent families, each of which survived this proceeding without any validity or claim-scope ruling.
Should you run an FTO against US11760714B2, US7335799B2, and US11613511B2?
Any company developing a generic, biosimilar, or next-generation ACL inhibitor — or a bempedoic acid-containing formulation — should treat these three patents as active clearance requirements. The dismissal without prejudice in this case provides zero FTO cover: no claim has been narrowed, invalidated, or found not infringed. The ongoing consolidated D.N.J. action means the litigation landscape around these patents is actively evolving and could produce claim construction guidance at any time.
PatSnap Eureka’s FTO Search Agent can map your compound’s structural features and method steps against the claim language of US11760714B2, US7335799B2, and US11613511B2, flag dependent claim fallback positions, and surface relevant PTAB prior art proceedings. Eureka’s litigation monitoring layer will also alert you to any Markman orders or trial dates in the consolidated proceeding at C.A. No. 24-05921 that could redefine claim scope relevant to your product strategy.
Run a freedom-to-operate analysis on US11760714B2 to assess your product’s exposure
Run FTO in Eureka →Similar bempedoic acid and ACL inhibitor patent cases in D.N.J.
Explore related Hatch-Waxman patent infringement actions involving bempedoic acid, ACL inhibitors, and cardiovascular drug IP litigated in the District of New Jersey.
What this case signals for the bempedoic acid and cardiovascular drug IP landscape
Esperion’s selective exit with Hetero while maintaining the consolidated action reveals a targeted, patent-by-patent enforcement posture in the NEXLETOL® generic defence.
Without-prejudice exits in Hatch-Waxman cases rarely mean the dispute is over
When a branded pharmaceutical plaintiff dismisses without prejudice against one ANDA filer while continuing against others, it typically signals either a licensing arrangement or a strategic sequencing of enforcement. Neither outcome eliminates the underlying patent risk for the dismissed party — or for other generics watching the consolidated case.
All three bempedoic acid patents remain fully enforceable and unchallenged
US11760714B2, US7335799B2, and US11613511B2 emerged from this case with no claim construction, no IPR estoppel, and no invalidity ruling attached. Any generic or biosimilar developer targeting the ACL inhibitor space should treat these patents as live enforcement risk until a substantive decision is issued in the ongoing consolidated proceedings.
Esperion v Hetero — key questions answered
Esperion asserted three patents: US11760714B2, US7335799B2, and US11613511B2. All three relate to bempedoic acid, the active ingredient in NEXLETOL®, covering the compound chemistry, formulations, and methods of use targeting ACL inhibition for LDL cholesterol reduction.
A without-prejudice dismissal under Fed. R. Civ. P. 41(a)(1)(A)(ii) means Esperion is not barred from refiling the same patent infringement claims against the Hetero Defendants in the future. No merits ruling was made, so neither validity nor infringement was adjudicated. Esperion’s patent rights remain fully intact.
Yes. The stipulated dismissal in Case No. 2:24-cv-06389 explicitly states that all claims and counterclaims involving other defendants in the consolidated action at C.A. No. 24-05921 remain pending. The dismissal applies only to the Hetero Defendants and does not resolve the broader enforcement action.
The stipulation provides that each party bears its own costs, fees, and expenses incurred in relation to the action. There was no fee-shifting order, meaning neither side was required to compensate the other’s litigation expenses. This is a common arrangement in Hatch-Waxman stipulated dismissals.
US7335799B2, filed in 2003, represents the foundational compound patent for bempedoic acid’s ACL-inhibiting chemistry. The two 2022-filed patents — US11760714B2 and US11613511B2 — extend protection to more specific formulation and method-of-use claims, a portfolio layering strategy designed to maintain litigation leverage and exclusivity beyond the original compound patent’s expiry window.
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