Pacira Pharmaceuticals v. Fresenius Kabi: EXPAREL Patent Dismissed With Prejudice
Pacira Pharmaceuticals filed a patent infringement action against Fresenius Kabi in the Northern District of Illinois over US12156940B1, protecting its EXPAREL bupivacaine liposome injectable suspension. The parties jointly stipulated to dismiss all claims and counterclaims with prejudice — and without costs to either side — just 141 days after filing.
EXPAREL patent dispute ends in mutual walk-away after 141 days
On 3 December 2024, Pacira Pharmaceuticals, Inc. — the commercial holder of EXPAREL, a liposomal bupivacaine injectable widely used for post-surgical pain management — filed a patent infringement action in the U.S. District Court for the Northern District of Illinois (Case No. 1:24-cv-12416) against Fresenius Kabi, a major generic and specialty pharmaceutical manufacturer. The suit centred on US12156940B1, a patent covering the 13.3 mg/mL bupivacaine liposome injectable suspension formulation underpinning EXPAREL.
The case closed on 23 April 2025, when both sides filed a stipulated dismissal under Federal Rules of Civil Procedure 41(a)(1) and 41(c). All claims, counterclaims, and affirmative defences asserted by Pacira Pharmaceuticals, Pacira Biosciences, Fresenius Kabi USA, and Jiangsu Hengrui Pharmaceuticals were dismissed with prejudice, with each party bearing its own costs. A with-prejudice dismissal bars both sides from re-litigating the same claims in any future proceeding.
The 141-day resolution is notably swift for pharmaceutical patent litigation and suggests the parties reached a private resolution — potentially a licensing arrangement, settlement, or commercial agreement — before the case reached claim construction or substantive motion practice. The public record does not disclose the terms of any underlying agreement, so the commercial rationale remains undisclosed. The involvement of Jiangsu Hengrui Pharmaceuticals as a named defendant signals this dispute likely had an ANDA or generic market-entry dimension.
Filing to Dismissed with Prejudice in 141 days
141 days — resolved well before the typical 2–3 year ANDA/Hatch-Waxman district court timeline
Dismissed with prejudice: what the stipulated exit means for both parties
Rule 41 stipulated dismissal with prejudice — all claims permanently closed
Under FRCP 41(a)(1) and 41(c), the parties jointly filed a stipulation dismissing every claim, counterclaim, and affirmative defence. A dismissal ‘with prejudice’ operates as a final adjudication on the merits: neither Pacira nor Fresenius Kabi can re-file the same claims arising from this patent and this alleged infringement in any U.S. court. Courts treat it as the functional equivalent of a judgment, making it one of the most legally conclusive voluntary exits available.
FRCP 41(a)(1) & 41(c)Pacira surrenders its infringement claims — but the patent itself survives
Dismissing with prejudice extinguishes Pacira’s right to sue Fresenius Kabi and Jiangsu Hengrui over the same alleged EXPAREL infringement. However, US12156940B1 remains a valid, enforceable patent and can be asserted against other parties. The no-costs provision suggests Pacira did not extract a public damages award, but any private licensing terms or market-delay agreement are not visible in the court record.
Patent remains enforceableFresenius Kabi cleared of this claim — but with-prejudice cuts both ways
Fresenius Kabi USA and Jiangsu Hengrui are permanently released from this specific infringement action, and no damages were publicly assessed. Their own counterclaims and affirmative defences — which may have included invalidity challenges — are also dismissed with prejudice, meaning they cannot re-raise those same invalidity arguments against Pacira on this patent in future litigation. This is a significant strategic concession if the defendants had strong invalidity positions.
Counterclaims also extinguishedSwift exit signals a likely private deal in the EXPAREL competitive landscape
Resolution in 141 days — before claim construction — is consistent with a negotiated commercial outcome: a licensing deal, authorised generic arrangement, or agreed market-entry timeline. EXPAREL is a high-revenue post-surgical analgesic; any generic entry by Fresenius Kabi or Hengrui would significantly impact Pacira’s market position. Competitors and generic filers watching this space should note that US12156940B1 was not invalidated and Pacira retains full enforcement rights against others.
Likely private resolutionFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Pacira Pharmaceuticals, Inc. | Company | Specialty pharma company — holder of US12156940B1 covering EXPAREL bupivacaine liposome injectableSearch in Eureka ↗ |
| Defendant | Fresenius Kabi | Individual | Global generic/specialty pharma manufacturer; Fresenius Kabi USA and Jiangsu Hengrui Pharmaceuticals named as defendantsSearch in Eureka ↗ |
| Plaintiff counsel | Corrin Nicole Drakulich | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Deanna J. Reichel | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Louis E. Fogel | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Michael T. Zoppo | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Fish & Richardson LLP | Law Firm | Representing Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Steven H. Sklar | Attorney | Counsel for Fresenius KabiSearch in Eureka ↗ |
| Defendant law firm | Leydig, Voit & Mayer, Ltd. | Law Firm | Representing Fresenius KabiSearch in Eureka ↗ |
| Presiding judge | Judge Steven C. Seeger | Judge | Illinois Northern District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulation invokes both Rule 41(a)(1) — governing voluntary dismissal by stipulation of all appearing parties — and Rule 41(c), which extends the same framework to counterclaims. By naming all four entities (two plaintiffs, two defendants) and explicitly extinguishing every claim, counterclaim, and affirmative defence, the parties left no residual dispute. The express no-costs language eliminates any post-dismissal fee motion risk. The with-prejudice designation is the most consequential element: it forecloses re-litigation on these specific infringement allegations, but does not limit Pacira from asserting US12156940B1 against unrelated third parties.
US12156940B1 — Bupivacaine liposome injectable suspension formulation
US12156940B1 (application number US18/761863) protects the formulation of bupivacaine liposome injectable suspension at a concentration of 13.3 mg/mL — the active pharmaceutical ingredient presentation marketed as EXPAREL. Liposomal encapsulation of bupivacaine extends the drug’s local anaesthetic effect well beyond conventional formulations, reducing reliance on opioids in post-operative pain management. The patent’s utility designation reflects a product-specific formulation claim, directly tying the IP to the commercial product rather than a broad platform technology.
EXPAREL generated over $500 million in annual U.S. net product sales for Pacira in recent years, making US12156940B1 a commercially critical asset. Generic entry by Fresenius Kabi or Jiangsu Hengrui would directly threaten that revenue. The patent’s formulation-level specificity means competitors must design around not just the active molecule but the liposomal delivery system itself — raising the technical bar for any generic or biosimilar entrant. For companies active in injectable analgesics, long-acting local anaesthetics, or liposomal drug delivery, this patent represents a significant freedom-to-operate consideration.
Should your team run an FTO analysis against US12156940B1?
Any company developing, manufacturing, or commercialising a bupivacaine liposome injectable suspension — particularly at or near 13.3 mg/mL concentrations — should treat US12156940B1 as a priority FTO target. This includes ANDA filers, 505(b)(2) applicants, contract manufacturers, and international pharmaceutical companies seeking U.S. market entry. The dismissal in this case did not invalidate the patent, and Pacira retains full enforcement rights. A design-around analysis should also consider the liposomal encapsulation methodology, excipient composition, and dosing presentations.
PatSnap Eureka’s FTO Search Agent can map US12156940B1’s claim scope against your formulation pipeline, flag related family members and continuations, and identify prior art that was or was not cited during prosecution. Eureka can also surface similar infringement actions Pacira has filed in other jurisdictions, giving your IP and regulatory teams a complete picture of enforcement risk before an ANDA filing or product launch decision is made.
Run a freedom-to-operate analysis on US12156940B1 to assess your product’s exposure
Run FTO in Eureka →Similar liposomal drug delivery patent cases in U.S. district courts
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What this case signals for the liposomal drug delivery IP landscape
A fast, cost-neutral exit in a high-stakes pharmaceutical patent case raises important questions for every player in the long-acting injectable analgesic market.
US12156940B1 was not invalidated — Pacira’s EXPAREL fortress stands
The with-prejudice dismissal extinguished Fresenius Kabi’s counterclaims, which likely included invalidity arguments. No court ruled the patent invalid. For competitors developing bupivacaine liposome formulations, US12156940B1 remains a live enforcement risk. Any new market entrant should conduct a fresh FTO analysis before filing an ANDA or launching a competing product.
Pre-claim-construction resolution compresses the invalidation window
Settling before claim construction prevents the public record from accumulating any narrowing claim interpretations. This preserves Pacira’s broadest possible claim scope for future enforcement. Patent challengers who hoped this litigation would produce limiting constructions will find the docket offers no such leverage for future disputes over US12156940B1.
Pacira v Fresenius — key questions answered
The case was dismissed with prejudice by joint stipulation on 23 April 2025, 141 days after filing. All claims, counterclaims, and affirmative defences were extinguished with no costs awarded to either party. No court ruling on the merits was issued.
Pacira asserted US12156940B1 (application number US18/761863), a patent covering the bupivacaine liposome injectable suspension formulation at 13.3 mg/mL — the formulation underlying its EXPAREL commercial product.
No. A dismissal with prejudice reflects a mutual agreement to end the litigation permanently, not a judicial ruling on patent validity. US12156940B1 was not adjudicated invalid and remains an enforceable patent that Pacira can assert against other parties.
The public record does not specify Hengrui’s precise role, but its inclusion as a named defendant alongside Fresenius Kabi USA is consistent with an ANDA or 505(b)(2) generic drug filing scenario, where both the U.S. applicant and the foreign manufacturer may be named as co-defendants in a Hatch-Waxman infringement action.
A mutual waiver of costs, disbursements, and attorneys’ fees in a with-prejudice pharmaceutical dismissal typically suggests the parties reached a private commercial resolution — such as a licensing agreement, authorised generic arrangement, or agreed market-entry timeline — rather than one side capitulating. The specific terms of any such agreement are not publicly disclosed.
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