Pacira v. Evenus, Hengrui & Fresenius Kabi: EXPAREL Patent Action Dismissed in 63 Days
Pacira Pharmaceuticals and Pacira BioSciences filed suit in the District of New Jersey against three defendants — Evenus Pharmaceuticals, Jiangsu Hengrui, and Fresenius Kabi USA — asserting US11925706B2 covering EXPAREL bupivacaine liposome injectable suspension. The action was voluntarily dismissed without prejudice just 63 days after filing, before any defendant had answered or moved for summary judgment.
EXPAREL generic challenge triggers rapid Pacira patent action — then swift withdrawal
On 10 July 2024, Pacira Pharmaceuticals, Inc. and Pacira BioSciences, Inc. filed a patent infringement action in the United States District Court for the District of New Jersey against Evenus Pharmaceuticals Laboratories, Inc., Jiangsu Hengrui Pharmaceuticals Co., Ltd., and Fresenius Kabi USA, LLC. The suit centred on US11925706B2 and alleged infringement through the defendants’ bupivacaine liposome injectable suspension product — a prospective generic equivalent to Pacira’s branded EXPAREL (266 mg/20 mL, 13.3 mg/mL). EXPAREL is a commercially significant long-acting local anaesthetic used widely in postsurgical pain management.
The case closed on 11 September 2024, just 63 days after filing, when Pacira filed a notice of voluntary dismissal without prejudice pursuant to Fed. R. Civ. P. 41(a)(1). The procedural basis was expressly noted: none of the three defendants had filed an answer or a motion for summary judgment, making unilateral voluntary dismissal without court order permissible. The without-prejudice designation means Pacira formally retains the right to refile the same claims against the same defendants at a future date, though whether any confidential resolution was reached alongside this filing remains unknown from the public record.
The 63-day duration is notably short even for pre-answer pharmaceutical patent litigation. Cases of this type — typically arising under the Hatch-Waxman Act or involving ANDA filings — routinely extend for months or years before substantive proceedings conclude. The speed of dismissal, combined with the without-prejudice designation, is consistent with early-stage licensing negotiations, a decision to refile on a stronger litigation posture, or the parties reaching a confidential commercial arrangement. Fish & Richardson and McCarter & English represented Pacira; no defendant counsel is recorded in the public docket at the time of dismissal.
Filing to Voluntary dismissal in 63 days
63 days from filing to voluntary dismissal — well below median ANDA patent litigation duration
Voluntarily dismissed: what Rule 41(a)(1) means for each party
Rule 41(a)(1) allows unilateral dismissal before any responsive pleading
Fed. R. Civ. P. 41(a)(1) permits a plaintiff to dismiss an action without a court order by filing a notice before the defendant serves an answer or a motion for summary judgment. Because none of the three defendants had filed either, Pacira could — and did — end the litigation unilaterally. No judicial approval was required, and no merits determination was made.
No merits adjudicationWithout prejudice preserves Pacira’s right to refile — but the record is silent on terms
A dismissal without prejudice does not bar Pacira from bringing the same claims again. This is legally distinct from a with-prejudice dismissal, which would extinguish those claims permanently. The public record in this case does not specify why Pacira chose to dismiss or whether any confidential agreement was reached. Practitioners should not interpret the without-prejudice designation alone as indicating either a settlement or a concession on the merits of US11925706B2.
Refile right preservedDefendants exit without admissions — but litigation risk remains live
All three defendants — Evenus, Jiangsu Hengrui, and Fresenius Kabi — are released from this specific action with no adverse finding against them. No invalidity ruling, no non-infringement finding, and no injunction issued. However, because the dismissal is without prejudice, these parties face the possibility of renewed litigation on US11925706B2 if their generic products reach commercialisation or if negotiations break down.
No adverse findingEXPAREL’s IP perimeter remains contested — generic entry timeline uncertain
The swift dismissal leaves the competitive landscape for bupivacaine liposome injectable suspension unresolved. US11925706B2 has not been tested or invalidated, and Pacira retains enforcement rights. For market participants and payers tracking EXPAREL generic entry, the outcome suggests proceedings are likely to continue — whether through refiling, negotiated licences, or parallel regulatory pathways — rather than representing a clean resolution.
Generic entry still uncertainFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Pacira Pharmaceuticals, Inc. | Company | Pharmaceutical company — holder of US11925706B2 covering EXPAREL bupivacaine liposome suspensionSearch in Eureka ↗ |
| Co-Plaintiff | Pacira Biosciences, Inc. | Company | Search in Eureka ↗ |
| Defendant | Evenus Pharmaceuticals Laboratories, Inc. | Company | Evenus Pharmaceuticals, Jiangsu Hengrui, and Fresenius Kabi — developers of generic bupivacaine liposome suspensionSearch in Eureka ↗ |
| Co-Defendant | Jiangsu Hengrui Pharmaceuticals Co., Ltd. | Company | Search in Eureka ↗ |
| Co-Defendant | Fresenius Kabi USA, LLC | Company | Search in Eureka ↗ |
| Plaintiff counsel | Cynthia Stencel Betz | 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 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 ↗ |
| Presiding judge | Judge N/A | Judge | New Jersey District CourtSearch in Eureka ↗ |
Official order — verbatim text
The dismissal notice cites Rule 41(a)(1) and expressly records that no defendant had answered or moved for summary judgment — language that serves a precise legal function: it establishes the procedural conditions for unilateral dismissal and insulates the filing from challenge. The without-prejudice designation is equally deliberate. No findings on infringement, validity, or claim scope of US11925706B2 were made. For both Pacira and the three defendants, the legal slate is clean — but the competitive dispute over bupivacaine liposome injectable suspension is unlikely to be fully resolved.
US11925706B2 — EXPAREL bupivacaine liposome injectable suspension
US11925706B2 (application number US18/325924) covers formulations of bupivacaine liposome injectable suspension — the active pharmaceutical ingredient in Pacira’s EXPAREL product, administered at 266 mg/20 mL (13.3 mg/mL). EXPAREL is a multivesicular liposomal formulation designed for extended-release local anaesthesia following surgery, reducing reliance on opioid analgesics. The patent’s liposomal delivery mechanism is central to both its therapeutic differentiation and its IP value, as it directly determines the product’s duration of action and bioavailability profile.
For the branded postsurgical pain management market, US11925706B2 represents a key line of defence against generic erosion. EXPAREL has generated substantial revenues for Pacira, and the entry of generic equivalents from established distributors such as Fresenius Kabi USA — backed by Chinese API sourcing from Jiangsu Hengrui — would materially affect pricing and market share. The patent has not been invalidated or found not infringed in any public proceeding, making it an active and unresolved enforcement asset. Competitors in the liposomal anaesthetic space should treat it as a primary FTO concern.
Should you run an FTO against US11925706B2?
Any company developing, importing, or commercialising a bupivacaine liposome injectable suspension in the United States — whether as an ANDA filer, a contract manufacturer, or a 505(b)(2) applicant — should run a freedom-to-operate analysis against US11925706B2 before advancing toward regulatory submission or commercial launch. This case demonstrates that Pacira is actively willing to enforce this patent against multiple parties simultaneously, and the without-prejudice dismissal means enforcement risk has not been extinguished.
PatSnap Eureka’s FTO Search Agent can map the claim scope of US11925706B2 against your product’s formulation parameters, identify relevant prior art that may support design-around strategies, and surface related Pacira patents in the bupivacaine liposome space that may also require analysis. For R&D and regulatory teams tracking EXPAREL generic entry, Eureka provides a structured landscape of the liposomal anaesthetic patent family to inform both product development and litigation readiness.
Run a freedom-to-operate analysis on US11925706B2 to assess your product’s exposure
Run FTO in Eureka →Similar bupivacaine liposome patent cases in U.S. district courts
Explore related pharmaceutical patent infringement actions involving liposomal drug formulations and ANDA challenges filed in U.S. district courts, particularly in New Jersey.
What this case signals for the bupivacaine liposome IP landscape
A 63-day voluntary dismissal in a multi-defendant pharmaceutical patent case rarely signals the end of the dispute.
Without-prejudice dismissals in pharma patent cases warrant close monitoring
When a patent holder dismisses without prejudice this early — before any answer is filed — it typically signals an ongoing negotiation or a strategic repositioning rather than surrender. IP teams tracking EXPAREL competitors should monitor for refiling activity against Evenus, Jiangsu Hengrui, or Fresenius Kabi in the coming months.
US11925706B2 has not been tested — its validity and scope remain live questions
No court has ruled on the validity or infringement scope of US11925706B2. Any company developing or commercialising a bupivacaine liposome injectable suspension should treat this patent as an active enforcement risk and conduct a thorough freedom-to-operate analysis before market entry.
Pacira v Evenus — key questions answered
Pacira Pharmaceuticals and Pacira BioSciences filed suit in the District of New Jersey on 10 July 2024 against Evenus Pharmaceuticals, Jiangsu Hengrui, and Fresenius Kabi USA, asserting US11925706B2 over a generic bupivacaine liposome injectable suspension. The case was voluntarily dismissed without prejudice on 11 September 2024 — 63 days after filing — before any defendant had answered or moved for summary judgment.
A dismissal without prejudice under Rule 41(a)(1) means no court has ruled on the validity or infringement of US11925706B2. Pacira retains the right to refile the same claims against the same defendants at any time. The patent remains in force and continues to represent an active enforcement risk for any party developing a competing bupivacaine liposome product.
The public record does not specify the precise roles of each defendant, but the combination of Jiangsu Hengrui — a major Chinese pharmaceutical manufacturer — and Fresenius Kabi USA, an established U.S. generic distributor, suggests a vertically integrated generic supply arrangement. This pairing is consistent with an ANDA filing that combines offshore API or finished-product manufacturing with a U.S. commercialisation partner.
The case involves a bupivacaine liposome injectable suspension product described in terms identical to EXPAREL’s dosage form, and the defendants include an established U.S. generic distributor. This profile is consistent with Hatch-Waxman ANDA litigation, though the public court record does not expressly confirm an ANDA filing. If a Paragraph IV certification was made, a 30-month stay may have been triggered regardless of the subsequent dismissal.
Pacira was represented by Fish & Richardson, PC and McCarter & English, LLP. Individual attorneys of record for the plaintiff include Cynthia Stencel Betz, Mark M. Makhail, and Michael Theodore Zoppo. No defendant counsel is recorded in the public docket, consistent with the case having been dismissed before any responsive pleading was filed.
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