Pacira v. Evenus & Fresenius Kabi: Bupivacaine Liposome Patent Dispute Dismissed With Prejudice
Pacira Pharmaceuticals and Pacira Biosciences brought a patent infringement action in New Jersey District Court against three generic and biosimilar defendants over US11426348B2, protecting bupivacaine multivesicular liposome compositions. After 718 days of litigation, all parties jointly stipulated to dismiss every claim and counterclaim with prejudice — and with no costs awarded to either side.
A three-defendant liposomal analgesia patent battle ends by mutual agreement
On 28 April 2023, Pacira Pharmaceuticals, Inc. and Pacira Biosciences, Inc. filed a patent infringement action in the District of New Jersey against three defendants — Evenus Pharmaceutical Laboratories, Inc., Fresenius Kabi USA, LLC, and Jiangsu Hengrui Medicine Co., Ltd. The suit centred on US11426348B2, a patent covering compositions of bupivacaine multivesicular liposomes, the core formulation technology behind Pacira’s long-acting local analgesic Exparel. The multi-defendant structure is consistent with ANDA or NDA-related litigation in which a branded pharmaceutical company sues multiple generic or biosimilar filers simultaneously.
After 718 days, the case closed on 15 April 2025 when all parties jointly stipulated to dismiss all claims, counterclaims, and affirmative defenses with prejudice pursuant to Federal Rules of Civil Procedure 41(a)(1) and 41(c). The stipulation explicitly stated that no costs, disbursements, or attorneys’ fees would be awarded to any party. A dismissal with prejudice is a final adjudication on the merits for res judicata purposes — the defendants cannot re-litigate the dismissed claims, and Pacira cannot refile the same infringement allegations against these parties.
The nearly two-year duration before a stipulated dismissal suggests the parties likely engaged in substantive discovery or settlement negotiations before reaching this resolution. The mutual no-costs provision and simultaneous dismissal of all counterclaims — which typically include invalidity and unenforceability defences — may indicate a confidential settlement or licensing arrangement, though the public record is silent on any such terms. Whether Fresenius Kabi or Jiangsu Hengrui obtained market access rights to the bupivacaine liposome technology as part of any agreement remains unknown.
Filing to Dismissed with Prejudice in 718 days
718 days — nearly two years of active ANDA-linked pharmaceutical patent litigation before resolution
Dismissed with prejudice: what the stipulated exit means for each party
Rule 41 dismissal with prejudice bars re-litigation of these claims
Under Federal Rules 41(a)(1) and 41(c), a stipulated dismissal with prejudice operates as a final judgment on the merits. Pacira cannot reassert the same infringement claims under US11426348B2 against these three defendants in future proceedings. Equally, the defendants’ counterclaims — which typically allege invalidity or unenforceability — are also extinguished, meaning no court ruling on patent validity was issued in this action.
Final on merits — no refilingPacira preserves the patent but forgoes a validity ruling
Pacira exits with US11426348B2 intact and unchallenged by any court judgment in this action. The patent’s validity was never adjudicated, which means Pacira retains the ability to assert it against new entrants. However, the dismissal of invalidity counterclaims with prejudice also means these three defendants cannot later pursue those same invalidity arguments in a new action — a structural benefit for the patent holder.
Patent survives, unadjudicatedDefendants lose invalidity claims but may have secured commercial terms
For Evenus, Fresenius Kabi, and Jiangsu Hengrui, the with-prejudice dismissal closes off the invalidity arguments they raised as counterclaims in this case. They cannot re-raise those specific claims against Pacira in subsequent litigation. Whether they received any commercial concession — such as a licence, authorised generic arrangement, or deferred market entry date — is not disclosed in the public record, but a mutual no-cost, no-fee settlement structure is often consistent with such negotiations.
Counterclaims extinguishedLiposomal bupivacaine IP landscape remains competitive post-dismissal
Exparel generates significant revenue for Pacira, and the liposomal bupivacaine formulation space has attracted multiple generic challengers. The survival of US11426348B2 without a validity ruling sustains Pacira’s enforcement posture against future ANDA or NDA filers not party to this action. Competitors outside this case — and new entrants developing alternative bupivacaine delivery technologies — should monitor Pacira’s patent portfolio closely, as enforcement risk remains active.
Patent enforcement risk persistsFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Pacira Pharmaceuticals, Inc. | Company | Specialty pharmaceutical company — holder of US11426348B2 covering bupivacaine multivesicular liposome compositionsSearch in Eureka ↗ |
| Co-Plaintiff | Pacira Biosciences, Inc. | Company | Search in Eureka ↗ |
| Defendant | Evenus Pharmaceuticals Laboratories, Inc. | Company | Generic and multinational pharmaceutical manufacturers seeking entry into the long-acting local analgesia marketSearch in Eureka ↗ |
| Co-Defendant | Fresenius Kabi USA, LLC | Company | Search in Eureka ↗ |
| Co-Defendant | Jiangsu Hengrui Medicine Co., Ltd. | Company | Search in Eureka ↗ |
| Plaintiff counsel | Cynthia Stencel Betz | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | John Edmund Flaherty | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Mark M. Makhail | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Michael Theodore Zoppo | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | THOMAS P. SCRIVO | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | YOUNG YU | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Fish & Richardson, PC | Law Firm | Representing Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Mccarter & English, LLP | Law Firm | Representing Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | O’TOOLE SCRIVO, LLC | Law Firm | Representing Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | O’Toole Scrivo, LLC | Law Firm | Representing Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Eric I. Abraham | Attorney | Counsel for Evenus Pharmaceuticals Laboratories, Inc.Search in Eureka ↗ |
| Defendant counsel | William Murtha | Attorney | Counsel for Evenus Pharmaceuticals Laboratories, Inc.Search in Eureka ↗ |
| Defendant law firm | Hill Wallack LLP | Law Firm | Representing Evenus Pharmaceuticals Laboratories, Inc.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | New Jersey District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulation invokes Rules 41(a)(1) and 41(c) to simultaneously terminate all offensive and defensive claims across three defendants. The explicit with-prejudice designation on both claims and counterclaims is significant: unlike a without-prejudice dismissal, this bars any party from re-litigating the same causes of action in any future proceeding. The mutual no-costs provision eliminates any inference of a prevailing party, and the joint filing by all parties suggests a negotiated resolution — though no settlement terms are disclosed in the public record.
US11426348B2 — Bupivacaine Multivesicular Liposome Compositions
US11426348B2 protects compositions of bupivacaine multivesicular liposomes — the formulation technology underlying Exparel, Pacira’s long-acting post-surgical local analgesic. Multivesicular liposome (MVL) technology encapsulates drug molecules within multiple aqueous chambers inside a lipid particle, enabling controlled, sustained release of bupivacaine over an extended period. The application (US17/590636) reflects a continuation strategy, suggesting Pacira has maintained a layered patent portfolio around its core Exparel technology to extend exclusivity beyond earlier patent families.
For competitors seeking to launch a generic or biosimilar version of Exparel, US11426348B2 represents a direct formulation barrier. The commercial stakes are high: Exparel is one of Pacira’s principal revenue-generating products in the post-operative pain management market. Any company developing bupivacaine liposome compositions for injectable or surgical-site administration must account for this patent and Pacira’s broader MVL portfolio. The continuation filing date suggests this patent may have a meaningful remaining term, making it a live enforcement risk for any ANDA filer or new entrant not covered by the terms of this stipulated dismissal.
Should your team run an FTO against US11426348B2?
Any pharmaceutical company — domestic or international — developing injectable bupivacaine formulations, multivesicular liposomal drug delivery systems, or extended-release local anaesthetics should treat US11426348B2 as a primary clearance target. This case confirms Pacira is willing to enforce this patent across multiple defendants simultaneously, including large generic and multinational manufacturers. R&D and regulatory teams advancing an ANDA or 505(b)(2) application for a bupivacaine liposome product should commission an FTO analysis before entering Phase III or submitting to FDA.
PatSnap Eureka’s FTO Search Agent can map the full claim scope of US11426348B2 against your product’s formulation parameters — including lipid composition, encapsulation method, particle size, and drug loading ratios. Eureka surfaces the full Pacira continuation family, identifies potential design-around space, and flags prior art that may bear on validity. For in-house IP teams managing Exparel-adjacent pipeline products, Eureka’s portfolio monitoring tools can alert you to new Pacira filings before they create enforcement exposure.
Run a freedom-to-operate analysis on US11426348B2 to assess your product’s exposure
Run FTO in Eureka →Similar bupivacaine and liposomal drug delivery patent cases in U.S. district courts
Cases involving multivesicular liposome or extended-release anaesthetic formulation patents litigated in the District of New Jersey and comparable pharmaceutical patent venues.
What this case signals for the liposomal drug delivery IP landscape
A with-prejudice mutual exit after nearly two years points to a negotiated resolution — and leaves the bupivacaine patent standing.
With-prejudice dismissal of counterclaims is a meaningful concession by defendants
Generic and biosimilar defendants typically fight to preserve invalidity arguments as leverage. Their agreement to dismiss counterclaims with prejudice suggests they may have obtained commercial value elsewhere — potentially a licence or agreed entry date — in exchange for abandoning invalidity challenges to US11426348B2.
Pacira’s patent survives without judicial scrutiny — a double-edged outcome
US11426348B2 emerges from this case without any court-issued validity ruling. For Pacira, this preserves enforcement options against other entrants. For the broader market, it means the patent’s actual scope and validity remain untested — creating continued uncertainty for any company developing competing bupivacaine liposome compositions.
Pacira v Evenus — key questions answered
The case was dismissed with prejudice on 15 April 2025 by joint stipulation of all parties under Federal Rules 41(a)(1) and 41(c). All claims and counterclaims were dismissed with no costs, disbursements, or attorneys’ fees awarded to any party. The case ran for 718 days from its filing on 28 April 2023.
Pacira asserted US11426348B2, filed under application number US17/590636, covering compositions of bupivacaine multivesicular liposomes. This patent protects the formulation technology underlying Exparel, Pacira’s long-acting local anaesthetic used for post-surgical pain management.
The dismissal with prejudice means no court ruled on the validity of US11426348B2 in this case. The patent survives unchallenged by any judicial determination. However, the defendants’ invalidity counterclaims were also dismissed with prejudice, meaning these three defendants cannot re-raise those same invalidity arguments against Pacira in future proceedings.
The multi-defendant structure — Evenus, Fresenius Kabi USA, and Jiangsu Hengrui Medicine — is consistent with ANDA or NDA-linked Hatch-Waxman litigation, where a branded pharmaceutical company sues all parties that filed competing applications simultaneously. Each defendant likely filed separately to seek approval for a generic or follow-on version of Exparel.
The public record does not disclose any settlement agreement. However, the combination of a with-prejudice mutual dismissal, no-costs provision, and 718-day litigation duration is consistent with a negotiated resolution — potentially including licence terms, authorised generic rights, or agreed market entry dates. These terms, if any exist, are not available in publicly filed documents.
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