DCT

1:25-cv-01445

Pacira Pharma Inc v. Whiteoak Group Inc

Log In
Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-01445, D. Del., 11/26/2025
  • Venue Allegations: Plaintiff alleges venue is proper in Delaware because Defendants WGI and Apotex are incorporated in the state and thus "reside" there, and because all Defendants committed acts of infringement in the district by submitting Abbreviated New Drug Applications (ANDAs) seeking to market products in Delaware.
  • Core Dispute: Plaintiff alleges that Defendants’ submission of ANDAs to the FDA for generic versions of EXPAREL® (bupivacaine liposome injectable suspension) constitutes an act of infringement of nine U.S. patents related to the drug's composition, manufacturing process, and methods of use.
  • Technical Context: The technology involves encapsulating the anesthetic bupivacaine within multivesicular liposomes (MVLs) to create an extended-release formulation for non-opioid, post-operative pain management.
  • Key Procedural History: Plaintiff’s U.S. Patent No. 11,033,495 was previously litigated in the District of New Jersey, where its original claim 7 was found invalid. Subsequent to that trial, the patent underwent an ex parte reexamination at the USPTO, which resulted in the cancellation of one claim and the allowance of 88 new claims, which are now asserted in this litigation.

Case Timeline

Date Event
2011-10-28 FDA approves commercial marketing of EXPAREL
2021-01-22 Priority Date for ’495, ’574, ’890, ’024, and ’047 Patents
2021-06-15 Issue Date for U.S. Patent No. 11,033,495
2023-11-21 Issue Date for U.S. Patent No. 11,819,574
2024-02-01 D.N.J. trial held regarding original claim 7 of the ’495 Patent
2024-05-20 Priority Date for ’483, ’940, ’468, and ’142 Patents
2024-11-19 Issue Date for U.S. Patent No. 12,144,890
2024-11-26 Issue Date for U.S. Patent No. 12,151,024
2024-12-03 Issue Date for U.S. Patent No. 12,156,940
2025-03-18 Issue Date for U.S. Patent No. 12,251,468
2025-05-13 Issue Date for U.S. Patent No. 12,296,047
2025-06-03 Issue Date for U.S. Patent No. 12,318,483
2025-07-29 Issue Date for U.S. Patent No. 12,370,142
2025-08-19 ’495 Patent ex parte reexamination certificate issued
2025-10-15 WGI and Apotex send ANDA Notice Letter to Pacira
2025-10-20 Qilu sends ANDA Notice Letter to Pacira
2025-11-07 WGI and Apotex send Supplemental Notice Letter to Pacira
2025-11-26 Complaint filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 11,033,495 - "Manufacturing of bupivacaine multivesicular liposomes", Issued June 15, 2021

The Invention Explained

  • Problem Addressed: The patent addresses the technical challenges of producing EXPAREL®, an extended-release anesthetic encapsulated in multivesicular liposomes (MVLs), at a large commercial scale (Compl. ¶ 61). The manufacturing process is described as complex and inherently unstable, particularly during the emulsification steps required to form the MVL's honeycomb-like structure (Compl. ¶¶ 64-65; ’495 Patent, col. 1:19-36).
  • The Patented Solution: The invention is a commercial-scale manufacturing process that creates a stable bupivacaine MVL formulation. The process involves creating a "water-in-oil" emulsion containing the drug and lipids, and then mixing it with a second aqueous solution to create a final "water-in-oil-in-water" emulsion that forms the MVLs (Compl. ¶ 65; ’495 Patent, col. 2:55-col. 3:13). The complaint alleges that this scaled-up process unexpectedly resulted in a product with greater stability (i.e., lower levels of lipid degradation products like erucic acid) (Compl. ¶ 66). This is illustrated in the cross-sectional diagram of an MVL particle, which shows the internal chambers that encapsulate and gradually release bupivacaine (Compl. p. 16).
  • Technical Importance: The technology enabled the reliable, scaled-up manufacturing of a first-of-its-kind, non-opioid analgesic that can control post-surgical pain for several days, reducing the need for addictive opioids (Compl. ¶¶ 1, 60).

Key Claims at a Glance

  • The complaint alleges infringement of "one or more claims" but does not identify specific claims (Compl. ¶ 149). It does note that the patent emerged from reexamination with new claims 23-110 (Compl. ¶ 121). Claim 23, a representative new independent claim, recites a method of treating pain by administering a composition produced by a specific commercial-scale process. The process itself is detailed in other independent claims, such as original claim 9. The essential process elements from claim 9 include:
    • mixing a first aqueous solution comprising phosphoric acid with a volatile water-immiscible solvent solution to form a water-in-oil first emulsion;
    • mixing the first emulsion with a second aqueous solution to form a water-in-oil-in-water second emulsion;
    • removing the volatile solvent to form an aqueous suspension of liposomes;
    • reducing the volume of the suspension by microfiltration;
    • exchanging the supernatant with a saline solution by diafiltration; and
    • further reducing the volume by microfiltration to achieve a target drug concentration. (’495 Patent, col. 22:50-col. 23:22).

U.S. Patent No. 11,819,574 - "Manufacturing of bupivacaine multivesicular liposomes", Issued November 21, 2023

The Invention Explained

  • Problem Addressed: As with the ’495 Patent, this invention addresses the difficulty of producing stable, high-quality batches of bupivacaine MVLs at a large commercial scale (Compl. ¶¶ 61, 64).
  • The Patented Solution: This patent claims the resulting product of the scaled-up manufacturing process, focusing on the improved stability characteristics of the final batches. The invention is defined not only by the manufacturing steps but also by the measurable qualities of the resulting batches, specifically a low concentration of the degradation product erucic acid after being stored for six months at 25°C. This links the process to a specific, verifiable stability outcome. (’574 Patent, col. 21:49-col. 22:12).
  • Technical Importance: This patent claims batches of the drug product defined by an improved stability profile, a key quality attribute for a pharmaceutical product that is challenging to manufacture consistently at scale (Compl. ¶ 61).

Key Claims at a Glance

  • The complaint alleges infringement of "one or more claims" without specifying which ones (Compl. ¶ 183). Independent claim 1 includes the following essential elements:
    • Batches comprising compositions of bupivacaine encapsulated MVLs prepared by a specific commercial scale process;
    • The process includes the water-in-oil-in-water double emulsion steps;
    • Each batch has a volume of about 100 L to about 250 L; and
    • An average erucic acid concentration of at least three such batches is about 105 µg/mL or less after six months of storage at 25° C. (’574 Patent, col. 21:49-col. 22:12).

Multi-Patent Capsule: U.S. Patent No. 12,144,890; U.S. Patent No. 12,151,024; and U.S. Patent No. 12,296,047 (the "Additional Erucic Acid Patents")

  • Technology Synopsis: These patents are part of the "Erucic Acid Patents" family and are directed to Pacira's scaled-up manufacturing process for EXPAREL (Compl. ¶ 60). They claim processes for preparing batches of bupivacaine encapsulated MVLs and compositions of such MVLs, similar to the ’495 and ’574 patents, focusing on aspects of the commercial-scale manufacturing that result in improved product stability as measured by erucic acid concentration (Compl. ¶¶ 78, 82, 86).
  • Asserted Claims: The complaint asserts "one or more claims" of each patent (Compl. ¶¶ 217, 251, 285).
  • Accused Features: The entirety of the WGI and Qilu ANDA products and their manufacturing processes are accused of infringement (Compl. ¶¶ 217, 251, 285).

Multi-Patent Capsule: U.S. Patent No. 12,318,483 (the "Method of Treatment Patent")

  • Technology Synopsis: This patent claims methods of treating pain by administering a composition of bupivacaine encapsulated MVLs to a subject (Compl. ¶ 92). The invention covers the use of EXPAREL for specific FDA-approved indications, such as producing postsurgical analgesia via infiltration or regional nerve blocks (Compl. ¶ 90).
  • Asserted Claims: The complaint asserts "one or more claims" of the patent (Compl. ¶ 319).
  • Accused Features: The use of the WGI and Qilu ANDA products in accordance with their proposed product labeling, which is expected to mirror EXPAREL's approved uses, is accused of infringement (Compl. ¶¶ 324-325).

Multi-Patent Capsule: U.S. Patent No. 12,156,940; U.S. Patent No. 12,251,468; and U.S. Patent No. 12,370,142 (the "IVRA Patents")

  • Technology Synopsis: These patents describe a new manufacturing process that allegedly improves upon prior processes by providing larger batch sizes and, critically, producing EXPAREL with an improved in vitro release (IVRA) stability profile (Compl. ¶ 97). The complaint explains that the IVRA test is essential for batch consistency and that failure of this test is a common reason for batch rejection (Compl. ¶ 96). The patented process results in batches with a flatter or slightly upward trend in drug release over 12 months, contrasting with older processes that showed a downward trend, as illustrated in the complaint's charts (Compl. pp. 23-24, Figs. 3A-3B).
  • Asserted Claims: The complaint asserts "one or more claims" of each patent (Compl. ¶¶ 353, 387, 421).
  • Accused Features: The WGI and Qilu ANDA products and their manufacturing processes are accused of infringing these patents by allegedly producing batches that meet the claimed IVRA stability profiles (Compl. ¶¶ 353, 387, 421).

III. The Accused Instrumentality

  • Product Identification: The accused instrumentalities are the Defendants' purported generic versions of EXPAREL® (bupivacaine liposome injectable suspension) for which they submitted ANDA No. 220735 (the "WGI ANDA Product") and ANDA No. 220830 (the "Qilu ANDA Product") (Compl. ¶¶ 17, 22).
  • Functionality and Market Context: The products are injectable suspensions containing bupivacaine as the active ingredient, intended for commercial manufacture and sale in the United States upon FDA approval (Compl. ¶¶ 17, 22, 119, 140). As generic versions of EXPAREL®, they are intended to be used for post-surgical pain management (Compl. ¶ 1). The act of filing the ANDAs with "Paragraph IV Certifications" asserting that Pacira's patents are invalid or not infringed is the statutory act of infringement under the Hatch-Waxman Act that triggered this lawsuit (Compl. ¶¶ 4, 117-118, 138-139).

IV. Analysis of Infringement Allegations

The complaint does not provide sufficient detail for a claim-chart analysis of any of the asserted patents. The infringement allegations are pleaded generally, stating on information and belief that the Defendants' ANDA products and the processes used to make them "are covered by one or more claims" of the Patents-in-Suit (e.g., Compl. ¶¶ 149, 183). This level of generality is common in Hatch-Waxman cases filed within the 45-day statutory window, often before the plaintiff has received and analyzed the confidential ANDA submission.

  • Identified Points of Contention:
    • Process Equivalence: A central factual question for the "Erucic Acid" and "IVRA" patents will be whether the manufacturing processes described in the confidential sections of the WGI and Qilu ANDAs include all the steps and parameters recited in Pacira's asserted process claims. This will require a step-by-step comparison of the respective manufacturing methods.
    • Product-by-Process Scope: For claims directed to compositions or batches defined by the process used to make them (e.g., claim 1 of the ’574 Patent), a key issue may be whether infringement requires practicing the exact claimed process, or whether producing a product with identical, distinguishing characteristics is sufficient.
    • Stability Profile Matching: For claims that recite specific stability outcomes (e.g., erucic acid levels in the ’574 Patent or IVRA release rates in the IVRA patents), a point of contention will be whether the Defendants' ANDA products will inevitably meet these claimed profiles when manufactured according to their proposed methods. This raises the question of whether the stability data in the Defendants' ANDAs will align with the numerical limitations in Pacira's claims.

V. Key Claim Terms for Construction

  • The Term: "commercial scale process"

  • Context and Importance: This term appears in the preambles of claims in the ’495 and ’574 Patents and is central to the patents' purpose of solving problems related to scaling up manufacturing from smaller, 45-liter batches (Compl. ¶ 61). Its construction will be critical for determining whether the Defendants' manufacturing processes, as detailed in their ANDAs, fall within the scope of the claims.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The patent specifications do not appear to provide an explicit numerical definition for "commercial scale." A party could argue that the term should be given its plain and ordinary meaning, which might encompass any production level intended for commercial sale, as opposed to laboratory or pilot-scale experimentation.
    • Evidence for a Narrower Interpretation: The specifications contrast the invention with a prior art 45-liter process and describe embodiments of the new process producing batches of about 200 L or more (’574 Patent, col. 15:45-50). Furthermore, claim 1 of the ’574 Patent explicitly recites a batch volume of "about 100 L to about 250 L." A party could argue this language contextually limits "commercial scale" to batches of at least 100 L, potentially excluding processes that operate at smaller volumes.

  • The Term: "average rate of change" (in cumulative percentage release)

  • Context and Importance: This term is critical to the IVRA Patents, which are distinguished by their improved stability profile over time (Compl. ¶ 97). The complaint includes charts plotting this "rate of change" to show the superiority of the new process (Compl. pp. 23-24). The definition and method of calculating this rate will be central to determining infringement of the IVRA patents.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The patents may describe the "rate of change" generally as the slope of the line comparing release percentages over time, as depicted in Figures 3A and 3B of the IVRA patents (e.g., '940 patent, Figs. 3A-3B). This could support a straightforward linear regression analysis based on stability data.
    • Evidence for a Narrower Interpretation: The patents specify that the data is generated from an IVRA test performed at specific intervals (0, 3, 6, 9, and 12 months) (Compl. ¶ 98). A party may argue that the term is implicitly limited to the specific methodology, time points, and statistical analyses detailed in the patent's examples, and that any deviation from this protocol in the Defendants' ANDA stability studies would fall outside the claim's scope.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement on the basis that Defendants, upon approval, will market and distribute their ANDA products with product labels and inserts that instruct healthcare professionals on methods of use (e.g., for nerve blocks) that are covered by claims of the ’483 Patent (Compl. ¶¶ 324-325). The complaint also alleges contributory infringement, stating the products are not staple articles of commerce and are especially adapted for infringing use (Compl. ¶¶ 157, 327).
  • Willful Infringement: Willfulness is alleged based on Defendants' knowledge of the patents, as evidenced by their filing of Paragraph IV certifications, and the allegation that they did so without a reasonable basis for their assertions of non-infringement or invalidity (Compl. ¶¶ 161, 195).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of prosecution history and claim scope: How will the court treat the 88 new claims of the ’495 Patent, which were allowed by the USPTO in an ex parte reexamination proceeding that occurred after a district court had found the patent’s original claim 7 invalid? The analysis will likely focus on whether the new claims are substantively different from the invalidated claim and the degree of deference, if any, afforded to the PTO’s subsequent examination.
  • A key evidentiary question will be one of process and product identity: Once discovery is completed, does the manufacturing process detailed in the Defendants’ confidential ANDA submissions read on every element of Pacira's asserted process claims? Further, will the resulting generic products inevitably exhibit the specific, quantitative stability characteristics (e.g., erucic acid levels, IVRA release rates) that are recited as limitations in several of Pacira's product and batch claims?
  • A central question of claim construction will be definitional: How will the court define "commercial scale process"? The interpretation of this term will be critical in determining the threshold for infringement of the key manufacturing patents, particularly if the Defendants' processes operate at a scale different from the specific examples provided in the patents-in-suit.