DCT

1:10-cv-00681

Celsis In Vitro Inc v. Xenotech LLC

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:10-cv-00681, N.D. Ill., 02/01/2010
  • Venue Allegations: Venue is alleged based on Defendants' business contacts in Illinois, including the presence of account managers, and the commission of alleged tortious acts directed at the judicial district.
  • Core Dispute: Plaintiff alleges that Defendants' pooled cryopreserved hepatocyte (liver cell) products and related drug testing services infringe a patent covering methods for repeatedly freezing and thawing such cells while maintaining high viability.
  • Technical Context: The technology relates to the cryopreservation of human hepatocytes, which are critical for in vitro preclinical drug metabolism and toxicity (ADMET) studies in the pharmaceutical industry.
  • Key Procedural History: The complaint alleges that Plaintiff provided Defendant XenoTech with written notice of the patent-in-suit on November 4, 2009. Following this notice, XenoTech allegedly launched a new accused product (CryostaX™) before formally declining a license on December 15, 2009. These events are asserted as a basis for willful infringement.

Case Timeline

Date Event
2005-04-21 ’929 Patent Priority Date
2008-07-09 Defendant Sekisui Chemical acquires Defendant XenoTech
2009-10-20 U.S. Patent No. 7,604,929 Issues
2009-10-20 Defendant XenoTech allegedly learns of ’929 Patent issuance
2009-11-04 Plaintiff Celsis sends written notice of infringement to XenoTech
2009-11-13 XenoTech acknowledges receipt of notice letter
2009-12-15 XenoTech declines license; allegedly launches CryostaX™ product
2010-02-01 Complaint Filed

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

U.S. Patent No. 7,604,929 - “Cellular Compositions and Methods for Their Preparation,” issued October 20, 2009

The Invention Explained

  • Problem Addressed: The patent identifies two primary problems in the field of drug testing using human liver cells (hepatocytes): the inconsistent supply and limited functional lifespan of fresh cells, and the significant donor-to-donor variation in metabolic enzyme activity, which complicates the reproducibility of experiments (’929 Patent, col. 3:23-31, col. 4:32-37). While single-cycle cryopreservation was known, it often resulted in a significant loss of viable cells (’929 Patent, col. 3:6-9).
  • The Patented Solution: The invention provides a method to create highly viable, pooled batches of hepatocytes that can survive repeated cycles of freezing and thawing. The core of the method involves taking a preparation of previously frozen-and-thawed hepatocytes, using a density gradient fractionation process (e.g., Percoll centrifugation) to separate the healthy, viable cells from the non-viable cells and debris, and then cryopreserving this purified population of viable cells a second time (’929 Patent, Abstract; col. 4:47-54). This enables the creation of large, standardized lots from multiple donors, addressing both the viability and variability problems (’929 Patent, col. 4:55-63).
  • Technical Importance: The described method allows for the commercial-scale production of standardized, high-viability, pooled hepatocyte preparations, which provides researchers with a more reliable and reproducible tool for in vitro drug metabolism and toxicity studies (’929 Patent, col. 4:55-63).

Key Claims at a Glance

  • The complaint alleges infringement of "one or more claims" of the ’929 patent (Compl. ¶1). Independent claim 1 is representative of the core inventive method.
  • Independent Claim 1 recites a method of producing a preparation of "multi-cryopreserved hepatocytes" with key steps including:
    • Providing hepatocytes that have already been "frozen and thawed."
    • (A) "subjecting" these thawed hepatocytes to "density gradient fractionation to separate viable hepatocytes from non-viable hepatocytes."
    • (B) "recovering the separated viable hepatocytes."
    • (C) "cryopreserving the recovered viable hepatocytes" to form the final preparation, which is required to have greater than 70% viability after a final thaw.
    • The claim includes a negative limitation that the hepatocytes are "not plated between the first and second cryopreservations."

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are Defendant XenoTech’s pooled cryopreserved hepatocyte products, specifically named "CryoXTreme™" and "CryostaX™," as well as the in vitro drug testing services that use these products (Compl. ¶¶17, 22, 38).

Functionality and Market Context

The complaint describes the accused products as "pooled cryopreserved hepatocytes" used for drug testing services (Compl. ¶17). The complaint alleges that XenoTech began making and selling these products after being acquired by Sekisui Chemical (Compl. ¶¶13, 16). It further alleges that the CryostaX™ product line was introduced to migrate customers away from the CryoXTreme™ product line after Plaintiff provided notice of its patent rights (Compl. ¶29).

IV. Analysis of Infringement Allegations

The complaint does not contain a claim chart or provide detailed factual allegations mapping the accused process to the elements of the patent claims. The infringement theory is presented in general terms. The complaint alleges that Defendant XenoTech uses processes and methods falling within the scope of the ’929 patent to manufacture its pooled cryopreserved hepatocyte products (Compl. ¶¶38, 44). The analysis below summarizes the likely points of dispute based on the complaint's narrative and the patent's claims.

No probative visual evidence provided in complaint.

  • Identified Points of Contention:
    • Technical Questions: A primary factual dispute will concern the specific steps of XenoTech's manufacturing process. Does XenoTech's procedure for creating its pooled products involve thawing previously cryopreserved cells, using a "density gradient fractionation" step to purify the viable cells, and then re-cryopreserving the purified cell population as required by Claim 1? The complaint pleads these facts on "information and belief" without providing direct evidentiary support (Compl. ¶38).
    • Scope Questions: The dispute may involve the scope of the negative limitation "not plated between the first and second cryopervations" (’929 Patent, col. 20:10-12). The court may need to determine whether any intermediate culturing steps in XenoTech's process constitute "plating" as contemplated by the patent.

V. Key Claim Terms for Construction

  • The Term: "density gradient fractionation"

    • Context and Importance: This term recites the core purification step of the claimed method (’929 Patent, col. 20:2-4). The infringement analysis will depend heavily on whether the purification method used by XenoTech, if any, falls within the scope of this term.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification discusses density gradient centrifugation as a preferred method but also mentions that separation can occur via "sequential washings," which could suggest that "fractionation" is not limited to a single technique (’929 Patent, col. 9:1-2).
      • Evidence for a Narrower Interpretation: The patent repeatedly highlights "percoll density centrifugation" as the exemplary and preferred embodiment (’929 Patent, col. 4:44-45, col. 9:34-36). A party could argue that the term should be construed as being limited to this specific type of centrifugation or functionally similar methods, potentially excluding other forms of cell separation or washing.

  • The Term: "multi-cryopreserved hepatocytes"

    • Context and Importance: This term in the preamble of Claim 1 describes the resulting product of the method. Its construction is important for defining the overall scope and purpose of the claimed process. Practitioners may focus on this term because it frames whether the claim requires a complete history of two freeze-thaw cycles.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification states the invention "permits the production and availability of hepatocyte preparations that may be repeatedly cryopreserved and thawed" (’929 Patent, col. 4:65-67). This could be interpreted as describing a capability of the resulting product, not necessarily a required historical process step for infringement.
      • Evidence for a Narrower Interpretation: Claim 1 explicitly recites a method performed on cells that "have been frozen and thawed" and concludes with a step of "cryopreserving" them again (’929 Patent, col. 19:62, col. 20:5-6). The claim also contains a limitation referring to a potential second thaw (’929 Patent, col. 20:8-10). This language strongly suggests the method covers a process that begins after a first thaw and ends with a second freeze, making the "multi-cryopreserved" nature integral to the claimed steps.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement against parent companies Sekisui Chemical and Sekisui Medical under 35 U.S.C. § 271(b) (Compl. Counts IV, V). The factual basis is the allegation that these entities, through their subsidiary/agent relationship, "actively induced" and "directed and controlling" XenoTech to perform the allegedly infringing activities in the United States (Compl. ¶¶32, 56, 62).
  • Willful Infringement: The complaint alleges willful infringement against all Defendants (Compl. ¶¶39, 45, 57). The claim is based on alleged knowledge of the ’929 patent as of its issue date, October 20, 2009, and from a specific notice letter sent by Celsis on November 4, 2009 (Compl. ¶¶19-20). The complaint further alleges that Defendants' continued infringement and the launch of the new CryostaX™ product line after receiving notice demonstrates bad faith (Compl. ¶¶22, 27, 30).

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

  1. A central issue will be one of evidentiary proof: What is the actual manufacturing process used by XenoTech to produce its CryoXTreme™ and CryostaX™ products? The outcome of the case will likely depend on whether discovery reveals that this process includes the key steps of thawing previously frozen cells, purifying them via density gradient fractionation, and subsequently re-cryopreserving the purified population.

  2. The case will likely involve a key question of claim scope: How should the term "density gradient fractionation" be construed? Whether XenoTech's purification techniques, if any, meet this definition will be a critical point of contention, turning on if the term is limited to the patent's preferred Percoll centrifugation embodiment or if it encompasses a broader range of cell separation methods.

  3. Should infringement be established, a major question for damages will be willfulness: Do the allegations—that XenoTech continued its activities and launched a new product line after receiving explicit notice of the ’929 patent—rise to the level of egregious conduct required for an enhancement of damages under 35 U.S.C. § 284?