Pacira v. Evenus & Fresenius Kabi: Federal Circuit Appeal Voluntarily Dismissed
Pacira Pharmaceuticals and Pacira Biosciences pursued a Federal Circuit infringement appeal against three generic and pharmaceutical rivals over patents covering bupivacaine multivesicular liposome manufacturing. After 203 days, the parties jointly agreed to dismiss the appeal under Fed. R. App. P. 42(b), with each side bearing its own costs — leaving the underlying merits unresolved on the appellate record.
A high-stakes liposomal analgesia appeal ends without a Federal Circuit verdict
Pacira Pharmaceuticals, Inc. and Pacira Biosciences, Inc. — the commercial stewards of the EXPAREL franchise — filed this Federal Circuit appeal on 19 September 2024, asserting infringement of US11033495B1 and US11179336B1, both directed to the manufacture of bupivacaine multivesicular liposomes. The defendants comprised Evenus Pharmaceuticals Laboratories, Jiangsu Hengrui Pharmaceuticals, and Fresenius Kabi USA — a coalition of generic and specialty pharmaceutical challengers with significant manufacturing and commercial reach in the anaesthesia space.
The appeal concluded on 10 April 2025 via a consensual dismissal under Federal Rule of Appellate Procedure 42(b), with both sides agreeing that each would bear its own costs. This procedural mechanism reflects a mutual decision to end the appellate proceeding — it is not a ruling on the merits, and the Federal Circuit issued no opinion on patent validity, claim scope, or infringement. The cost-neutral structure suggests a negotiated resolution rather than a unilateral withdrawal by either party.
A 203-day duration from filing to dismissal is consistent with an appeal that proceeded through early briefing stages before settlement or commercial resolution was reached. The public record is silent on whether a licensing arrangement, product design-around, or broader commercial agreement underlies the dismissal. What remains unresolved from this proceeding is whether the Pacira liposome manufacturing patents would have survived Federal Circuit scrutiny — a question that retains significance for any remaining ANDA or generic entrant litigation involving these patents.
Filing to Voluntary dismissal in 203 days
203 days from filing to dismissal — typical for a negotiated Federal Circuit appeal withdrawal
Appeal dismissed by agreement: what Fed. R. App. P. 42(b) means for both sides
Fed. R. App. P. 42(b): consensual dismissal, no merits adjudication
Federal Rule of Appellate Procedure 42(b) allows parties to dismiss an appeal by stipulation. The Federal Circuit issued no opinion on validity, claim construction, or infringement. This means no binding appellate precedent was created — the patents’ enforceability is neither confirmed nor undermined by this proceeding. The dismissal order is purely procedural.
No merits rulingVoluntary dismissal: with or without prejudice — the record is silent
The order records a voluntary dismissal under Rule 42(b) but does not specify whether it is with or without prejudice to refiling. Under Rule 42(b), the default is typically without prejudice unless the parties stipulate otherwise — but practitioners should review the full order language. The public docket does not disclose a settlement agreement or licensing terms, so the legal finality of this dismissal with respect to the specific patents and defendants remains uncertain from available records.
Prejudice unspecifiedNo adverse ruling for Evenus, Hengrui, or Fresenius Kabi at this stage
The three defendants — Evenus Pharmaceuticals, Jiangsu Hengrui, and Fresenius Kabi USA — exit this Federal Circuit proceeding without an infringement finding against them. However, the dismissal does not constitute a finding of non-infringement or invalidity. Depending on any underlying agreement, exposure to these patents in future district court or ITC proceedings may persist. Each side bearing its own costs suggests neither party conceded a clearly losing position.
No infringement findingBupivacaine liposome market entry timelines remain commercially uncertain
The dismissal leaves the competitive landscape for generic or biosimilar bupivacaine multivesicular liposomes unresolved. Pacira’s patents US11033495B1 and US11179336B1 remain formally intact and enforceable. Parties developing or commercialising competing liposomal local anaesthetic products — particularly those pursuing ANDA or 505(b)(2) pathways — should treat these patents as live risks requiring FTO analysis, as no appellate ruling has weakened their scope.
Patents remain enforceableFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Pacira Pharmaceuticals, Inc. | Company | Pharmaceutical company — holder of US11033495B1 and US11179336B1 covering bupivacaine liposome manufacturingSearch in Eureka ↗ |
| Co-Plaintiff | Pacira Biosciences, Inc. | Company | Search in Eureka ↗ |
| Defendant | Evenus Pharmaceuticals Laboratories, Inc. | Company | Generic and specialty pharma challengers: Evenus Pharmaceuticals, Jiangsu Hengrui, and Fresenius Kabi USASearch 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 | Ashley Cade | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Corrin Drakulich | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Deanna Jean Reichel | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | John C. O’Quinn | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Michael T. Zoppo Esq. | Attorney | Counsel for Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | William H. Burgess | 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 | Kirkland & Ellis LLP | Law Firm | Representing Pacira Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Daryl L. Wiesen | Attorney | Counsel for Evenus Pharmaceuticals Laboratories, Inc.Search in Eureka ↗ |
| Defendant counsel | Kevin Jon DeJong | Attorney | Counsel for Evenus Pharmaceuticals Laboratories, Inc.Search in Eureka ↗ |
| Defendant counsel | Kevin P. Martin | Attorney | Counsel for Evenus Pharmaceuticals Laboratories, Inc.Search in Eureka ↗ |
| Defendant law firm | Goodwin Procter LLP | Law Firm | Representing Evenus Pharmaceuticals Laboratories, Inc.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The dismissal order is terse by design: it records mutual consent under Fed. R. App. P. 42(b) and allocates costs equally. Notably, the absence of any merits language means the order creates no issue preclusion, no claim construction precedent, and no validity determination. For Pacira, the patents emerge untouched; for the defendants, no safe harbour of non-infringement has been established. The equal cost allocation is consistent with a negotiated exit rather than a concession by either side, though the underlying commercial terms — if any — are not reflected in the public docket.
US11033495B1 & US11179336B1 — bupivacaine multivesicular liposome manufacturing
US11033495B1 and US11179336B1, filed under application numbers US17/156400 and US17/319956 respectively, protect methods and compositions relating to the manufacture of bupivacaine multivesicular liposomes (MVLs). MVL technology encapsulates the local anaesthetic bupivacaine within a matrix of multiple aqueous chambers surrounded by lipid membranes, enabling extended post-operative pain relief — the core of Pacira’s EXPAREL product. These patents represent a later-generation layer of Pacira’s manufacturing IP, filed after EXPAREL’s commercial launch, suggesting refinement or process optimisation claims.
For the liposomal drug delivery sector, these patents are strategically significant because they sit at the intersection of formulation science and manufacturing process — two claim categories that are difficult to design around simultaneously. Competitors seeking to produce generic or biosimilar extended-release bupivacaine products face a dual barrier: formulation claims that define the MVL structure and process claims that govern how it is made. The involvement of Jiangsu Hengrui — a major Chinese generic manufacturer — and Fresenius Kabi, a global injectable drug leader, confirms that multiple well-resourced competitors regard these patents as the primary obstacle to market entry.
Should you run an FTO against US11033495B1 and US11179336B1?
Any company developing, manufacturing, or importing bupivacaine multivesicular liposome products — whether as an ANDA filer, a 505(b)(2) applicant, a CDMO, or a finished-dose generic entrant — should conduct a rigorous FTO analysis against both patents. The Federal Circuit dismissal provides no clearance. Both patents remain in force, and their claims likely cover core steps in MVL manufacturing that are difficult to avoid. Companies sourcing MVL intermediates or API from third-party manufacturers should also assess whether those upstream steps implicate the method claims.
PatSnap Eureka’s FTO Search Agent can map the independent and dependent claims of US11033495B1 and US11179336B1 against your proposed manufacturing process in minutes — identifying claim elements that require clearance and surfacing prior art that may support a validity challenge. For teams monitoring the EXPAREL biosimilar landscape, Eureka’s litigation tracking module surfaces related district court and PTAB proceedings in real time, ensuring your freedom-to-operate assessment stays current as the Pacira patent portfolio evolves.
Run a freedom-to-operate analysis on US11033495B1 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit cases: liposomal drug delivery patent appeals
Federal Circuit appeals involving liposomal and extended-release pharmaceutical formulation patents — comparable to this bupivacaine MVL dispute — analysed below.
What this case signals for the liposomal drug delivery IP landscape
A cost-neutral voluntary dismissal at the Federal Circuit suggests back-channel resolution — but Pacira’s manufacturing patents remain fully armed.
Pacira’s liposome manufacturing patents survive without appellate challenge
Because the Federal Circuit issued no opinion, US11033495B1 and US11179336B1 carry no appellate-level weaknesses. Any competitor targeting the bupivacaine MVL space must treat these patents as undiminished in scope. FTO clearance against both patents is essential before advancing clinical or commercial programmes.
Cost-neutral dismissal typically signals a commercial deal, not capitulation
When both sides bear their own costs in a Rule 42(b) dismissal, it typically suggests a negotiated resolution — a licence, a supply agreement, or a market-entry timing arrangement. Patent professionals monitoring EXPAREL biosimilar development should watch for downstream commercial announcements from Evenus, Hengrui, or Fresenius Kabi as potential indicators of deal terms.
Pacira v Evenus — key questions answered
The Federal Circuit appeal No. 24-2334 was voluntarily dismissed on 10 April 2025 under Fed. R. App. P. 42(b) by agreement of the parties. No merits ruling was issued. Each side bore its own costs. The case concerned alleged infringement of US11033495B1 and US11179336B1 covering bupivacaine multivesicular liposome manufacturing.
Yes. The voluntary dismissal under Rule 42(b) issued no opinion on validity or infringement. Both patents remain in force and carry no appellate-level weaknesses from this proceeding. Competitors developing bupivacaine MVL products should treat these patents as fully enforceable and conduct updated FTO analysis before advancing their programmes.
A Rule 42(b) dismissal by stipulation means the Federal Circuit issued no ruling on infringement, validity, or claim construction. Evenus, Jiangsu Hengrui, and Fresenius Kabi receive no finding of non-infringement or invalidity. Their exposure to these patents in future proceedings — whether district court, ITC, or PTAB — is not resolved by this dismissal.
The order reflects the parties’ own agreement rather than a judicial cost allocation. Under Fed. R. App. P. 42(b), parties may stipulate to dismissal on agreed terms, including cost sharing. A cost-neutral outcome typically suggests a negotiated resolution where neither side conceded a clearly losing position, though no settlement details are disclosed in the public record.
Hengrui’s presence as a co-defendant suggests the alleged infringement may have involved manufacturing activities outside the United States, consistent with Hengrui’s role as a major Chinese pharmaceutical manufacturer. This raises questions about cross-border method claim applicability and import-based infringement under 35 U.S.C. § 271(g), which are relevant for companies sourcing bupivacaine MVL materials from Chinese CDMOs.
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