Pacira Pharmaceuticals vs. Qilu: Voluntary Dismissal in EXPAREL® Bupivacaine Liposome Patent Dispute

Case Overview

In a closely watched pharmaceutical patent dispute, Pacira Pharmaceuticals, Inc. voluntarily dismissed its infringement action against Chinese drugmaker Qilu Pharmaceutical (Hainan) Co., Ltd. after just 78 days — before the defendant was even served with process. Filed December 1, 2025, and closed February 17, 2026, in the Eastern District of Pennsylvania, Case No. 2:25-cv-06742 involved nine issued U.S. patents protecting EXPAREL® (bupivacaine liposome injectable suspension), one of the most commercially significant long-acting local anesthetics on the market.

The dismissal without prejudice under Fed. R. Civ. P. 41(a)(1)(A)(i) leaves the door open for future litigation, making this case a critical signal for pharmaceutical IP professionals, ANDA filers, and generic drug developers operating in the liposomal drug delivery space.

The Parties

Patents at Issue

Nine U.S. patents were asserted, covering formulation, manufacturing, and method-of-use aspects of liposomal bupivacaine technology. These patents span a mix of continuation and independent applications, reflecting a layered prosecution strategy commonly employed to extend exclusivity over core liposomal drug delivery innovations:

• • US12318483B1 (App. No. 18/957404)
• • US11033495B1 (App. No. 17/156400)
• • US12296047B2 (App. No. 18/943310)
• • US12156940B1 (App. No. 18/761863)
• • US12370142B1 (App. No. 19/077685)
• • US12251468B1 (App. No. 18/761898)
• • US12151024B2 (App. No. 17/840104)
• • US11819574B2 (App. No. 17/719716)
• • US12144890B2 (App. No. 18/325927)

The Verdict & Legal Analysis

Outcome

The case was terminated by **voluntary dismissal without prejudice** pursuant to Fed. R. Civ. P. 41(a)(1)(A)(i). No damages were awarded, no injunctive relief was granted, and no claim construction or merits rulings were issued. The dismissal without prejudice explicitly preserves Pacira’s right to re-file identical or similar claims against Qilu in the future.

Verdict Cause Analysis

The formal cause of action was patent infringement. However, the procedural mechanism of pre-service voluntary dismissal means no substantive legal findings were reached. The strategic calculus behind such early dismissals in pharmaceutical patent cases typically involves one or more of the following scenarios:

• Licensing or settlement negotiations initiated after filing that rendered continued litigation unnecessary at this stage.
• Regulatory intelligence: the plaintiff may have filed to establish a litigation record or preserve rights pending an ANDA or NDA submission by Qilu with the FDA.
• Tactical positioning: establishing a paper record of patent assertion for licensing leverage or future litigation reinstatement.
• Portfolio refinement: Pacira may have determined that additional patents (including some of the newer, higher-numbered patents in the asserted set) warrant further prosecution hardening before litigation proceeds to merits.

Legal Significance

While this dismissal produces no precedential ruling, several legally significant observations emerge:

• **Nine-Patent Assertion Strategy:** Asserting nine patents simultaneously against a single defendant signals an aggressive portfolio enforcement posture. The inclusion of patents with application numbers ranging from 2022 to 2024 (based on filing series) suggests Pacira is actively layering new IP around EXPAREL® to address potential design-arounds.
• **Rule 41(a)(1)(A)(i) as a Strategic Tool:** The clean use of this rule — enabled by the deliberate choice not to serve the defendant — gives plaintiffs maximum tactical flexibility. It is a notable reminder that complaint filing itself carries strategic value independent of litigation outcome.
• **Without Prejudice Preservation:** The explicit without-prejudice designation ensures all nine patent claims survive for reassertion. Any statute of limitations or laches arguments will reset upon re-filing, subject to applicable limitations periods.