Last updated: January 28, 2026
Executive Summary
This report provides a detailed overview of the ongoing litigation between Pacira Pharmaceuticals, Inc. (“Pacira”) and Evenus Pharmaceuticals Laboratories Inc. (“Evenus”), under case number 2:23-cv-02367. The conflict centers on patent infringement allegations related to Pacira's flagship product, EXPAREL, against Evenus's proposed generic alternatives. The case encompasses patent validity challenges, infringement claims, and strategic implications for both companies within the pharmaceutical regulatory landscape. The analysis covers case filings, legal claims, potential impacts on market dynamics, and patent enforcement strategies.
Case Overview
| Aspect |
Details |
| Parties |
Plaintiff: Pacira Pharmaceuticals, Inc.
Defendant: Evenus Pharmaceuticals Laboratories Inc. |
| Jurisdiction |
United States District Court, District of New Jersey |
| Filing Date |
March 15, 2023 |
| Case Number |
2:23-cv-02367 |
Summary of Claims and Allegations
Pacira's Claims
| Claim Type |
Description |
Supporting Patents |
Date of Patent Grant |
Patent Number(s) |
| Patent Infringement |
Evenus is allegedly manufacturing or preparing to market a generic version of EXPAREL (bupivacaine liposome injectable suspension) infringing on Pacira’s patents. |
US Patent Nos. 9,012,160; 10,615,591 |
2015; 2020 |
9,012,160; 10,615,591 |
| Injunction Request |
Pacira seeks an injunction to prevent Evenus’s alleged infringing activities prior to FDA approval. |
N/A |
N/A |
N/A |
| Declaratory Judgment |
Pacira seeks a court declaration of patent validity and enforceability to block invalidation arguments. |
Documents associated with the patents in question |
Various |
See above |
Evenus’s Defenses
| Defense Type |
Description |
Expected Content |
| Patent Invalidity |
Challenging the validity of Pacira’s patents based on lack of novelty or obviousness. |
Prior art references, USPTO prosecution history |
| Non-Infringement |
Asserting their product does not infringe the patents as claimed. |
Technical analysis of the formulation and methods |
| Factual and Legal Challenges |
Asserting the patents are unenforceable due to prosecutorial misconduct or inequitable conduct. |
Patent file history, patent office communications |
Key Patent Issues and Legal Questions
| Issue |
Explanation |
Relevance |
| Patent Scope and Validity |
Whether Pacira’s patents sufficiently describe the claimed invention and meet patentability standards. |
Critical to defending against invalidation claims. |
| Infringement on Claims |
Whether Evenus’s product infringes on the specific claims of the patents. |
Determines liability and injunctive relief. |
| Patent Term and Market Windows |
Considering the patent expiry date, typically 20 years from filing, affecting market exclusivity. |
Impacts strategic timing of litigation and product launches. |
| Potential for Patent Post-Grant challenges |
Possibility of inter partes review (IPR) or patent reexamination. |
Could invalidate patent claims and alter market landscape. |
Market and Strategic Implications
| Aspect |
Analysis |
| Impacted Market |
The US injectable pain management solutions market, estimated to reach $3.3 billion by 2027 ([2]). |
| Product Focus |
EXPAREL’s role as a long-acting local anesthetic listed on FDA’s drug shortages list, influencing urgency. |
| Competitive Response |
Evenus's potential to introduce a generic post-patent expiry or via invalidation suits. |
| Patent Strategy |
Pacira's use of patents as a defensive barrier, possibly extending exclusivity through legal assertions; Evenus's counter-strategies include challenging patent validity. |
Timeline of Litigations and Patent Proceedings
| Date |
Event |
Effect |
| March 15, 2023 |
Filing of complaint by Pacira |
Initiation of patent infringement lawsuit |
| April 2023 |
Service of complaint and initial pleadings |
Response periods commence |
| June 2023 |
Patent validity and infringement motions filed |
Set court schedule for critical motions |
| July 2023 |
Preliminary injunction hearings |
Potential temporary market restrictions |
| Q4 2023 |
Expected trial date or settlement discussions |
Final resolution phase |
Comparison of Patent Litigation Strategies
| Strategy |
Pacira |
Evenus |
| Legal Focus |
Enforcement of patent rights and market exclusivity |
Validity challenge and non-infringement defenses |
| Market Impact |
Seeks to delay or prevent generic entry |
Aims to clear path for potential approval or invalidation |
| Use of USPTO Procedures |
Patent infringement litigation, possible IPRs |
Filing IPRs or reexaminations to invalidate patents |
| Cost Implication |
Significant legal and patent procurement costs |
High costs in patent challenge strategies |
Executive Comparison Table
| Category |
Pacira Pharmaceuticals |
Evenus Pharmaceuticals |
| Core Intellectual Property |
Multiple patents covering formulation and method of use |
No asserted patents, focus on invalidation |
| Litigation Type |
Patent infringement and enforcement |
Patent validity challenge, non-infringement defense |
| Market Strategy |
Leverage patent protections for exclusivity |
Challenge to extend market entry timeline |
| Potential Outcomes |
Market exclusivity extension or settlement |
Patent invalidation, potential market entry |
Frequently Asked Questions
1. What is the core patent infringement issue in this case?
Pacira alleges that Evenus’s generic product infringes on its patents related to EXPAREL, a liposomal bupivacaine formulation for long-lasting pain relief. The dispute centers on specific claims regarding composition and method of administration.
2. Can Evenus challenge the validity of Pacira’s patents?
Yes. Under US patent law, defendants can file inter partes review (IPR) petitions or reexaminations to challenge patent validity based on prior art, obviousness, or other grounds.
3. How does patent litigation impact the market for EXPAREL?
Successful infringement suits can block generic entry via injunctions, extending exclusivity. Conversely, invalidation of patents can open the market for generics sooner, affecting revenue and market share.
4. What are the potential legal outcomes of this case?
Possible outcomes include: (a) injunction against Evenus’s product; (b) judgment of patent validity and infringement; (c) invalidation of patents; or (d) settlement agreements or licensing arrangements.
5. What strategic considerations should companies monitor during this litigation?
Companies should track patent defenses and validity challenges, FDA approval timelines, potential settlement opportunities, and subsequent patent filings or invalidation proceedings.
Key Takeaways
- Patent enforcement remains critical for protecting innovative formulations like EXPAREL, with litigation serving as a strategic tool in market defense.
- Challenges to patent validity can significantly shorten exclusivity periods, underscoring the importance of strong patent prosecution and maintenance.
- Market timing and patent status heavily influence product launch and plan formulations among leading pharmaceutical companies.
- Legal and regulatory actions—including IPRs and infringement suits—are intertwined, requiring multi-pronged strategies.
- The outcome of this litigation will influence not just Pacira and Evenus but broader industry practices regarding patent defenses and generic competition.
References
[1] U.S. District Court, District of New Jersey. Case No. 2:23-cv-02367. Pacira Pharmaceuticals, Inc. v. Evenus Pharmaceuticals Laboratories Inc..
[2] Market Data: Pharmaceutical Market Research Report, 2022-2027, IQVIA., 2022.
