DCT

1:01-cv-02275

Zymogenetics Inc v. British Technology Group Ltd

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Key Events
Amended Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:01-cv-02275, D.D.C., 02/21/2002
  • Venue Allegations: Venue is asserted under 35 U.S.C. § 146, which governs civil actions to obtain a patent following a decision by the Board of Patent Appeals and Interferences, and general venue statutes.
  • Core Dispute: Plaintiff ZymoGenetics seeks judicial review of a decision from the U.S. Patent and Trademark Office's Board of Patent Appeals and Interferences, challenging the Board's findings on the patentability of its own claims and seeking to overturn the outcome of an interference proceeding concerning technology for producing recombinant Factor IX.
  • Technical Context: The dispute concerns methods for the high-yield production of biologically active Factor IX, a critical protein for blood coagulation, using recombinant DNA technology in mammalian cell cultures.
  • Key Procedural History: This case arises from USPTO Interference No. 103,463. In that proceeding, the Board of Patent Appeals and Interferences found that the Plaintiff's inventors (Hagen et al.) were entitled to priority for the subject matter of the interference count, but simultaneously held certain of their claims unpatentable under 35 U.S.C. § 112. The Plaintiff is now appealing these adverse patentability decisions to the district court pursuant to 35 U.S.C. § 146.

Case Timeline

Date Event
1985-04-17 Filing Date for ZymoGenetics's U.S. Patent Application No. 06/724,311
1985-04-22 Priority Date for U.S. Patent No. 4,770,999
1988-09-13 Issue Date for U.S. Patent No. 4,770,999
2000-01-31 Administrative Patent Judge holds Hagen et al. claims unpatentable under 35 U.S.C. § 112
2001-07-31 Board of Patent Appeals and Interferences issues final decision in Interference No. 103,463
2002-02-21 Complaint Filing Date

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

No probative visual evidence provided in complaint.

U.S. Patent No. 4,770,999 - High Yield Production of Active Factor IX

  • Patent Identification: U.S. Patent No. 4,770,999, "High Yield Production of Active Factor IX," issued September 13, 1988

The Invention Explained

  • Problem Addressed: The patent addresses the difficulty in producing the human blood-clotting protein Factor IX in large quantities and in a biologically active form using recombinant DNA methods. Prior art methods suffered from low yields or produced protein that was not functional, as Factor IX requires a specific post-translational modification (gamma-carboxylation) to be active. (U.S. Patent No. 4,770,999, col. 2:5-8).
  • The Patented Solution: The invention provides a method to solve this problem by transfecting a specific type of host cell—a Chinese Hamster Ovary (CHO) cell—with the DNA sequence for human Factor IX. The key insight is that culturing these engineered CHO cells in a medium supplemented with vitamin K enables the cells to correctly perform the necessary gamma-carboxylation, resulting in high yields of biologically active Factor IX. (U.S. Patent No. 4,770,999, Abstract; col. 2:9-18). The patent's Figure 1 illustrates the genetic expression plasmids, such as p91023-IX, used to transfect the host cells. (U.S. Patent No. 4,770,999, Fig. 1).
  • Technical Importance: This method provided a potential pathway to a stable, reliable source of therapeutic Factor IX for treating hemophilia B, avoiding the risks of viral transmission associated with sourcing the protein from pooled human plasma. (U.S. Patent No. 4,770,999, col. 1:19-27).

Key Claims at a Glance

  • The complaint does not explicitly assert specific claims. However, given the subject matter of the ’999 patent, the dispute centers on the subject matter embodied by its independent claim.
  • Independent Claim 1:
    • A method for producing biologically active human Factor IX in high yield
    • comprising culturing a CHO cell line transfected with chromosomally-integrated Factor IX cDNA
    • in medium containing vitamin K.
  • The complaint does not reserve the right to assert dependent claims as it is not a standard infringement action.

III. The Accused Instrumentality

This action is brought under 35 U.S.C. § 146 to review a decision of the Board of Patent Appeals and Interferences and does not allege infringement of an issued patent by a commercial product. Therefore, there is no accused instrumentality.

IV. Analysis of Infringement Allegations

The complaint does not contain allegations of patent infringement.

V. Key Claim Terms for Construction

  • The Term: "CHO cell line"
  • Context and Importance: Practitioners may focus on this term because the choice of the host cell line is a fundamental element of the claimed invention. The interference proceeding would have turned on which party first invented the method of producing Factor IX specifically in this type of cell, and whether each party's patent application adequately described and enabled the use of CHO cells for this purpose at their respective priority dates. The patentability of ZymoGenetics's claims may depend on the scope and definition of this term. (U.S. Patent No. 4,770,999, col. 11:11-15).
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claims refer to a "CHO cell line" generally, which could be argued to encompass any cell line derived from Chinese Hamster Ovary cells capable of being transfected and expressing the protein. The specification states that "Even cells that have not previously been demonstrated to provide y-carboxylation, can be shown to provide active Factor IX by this method." (U.S. Patent No. 4,770,999, col. 2:15-18).
    • Evidence for a Narrower Interpretation: The patent's examples exclusively use a specific type of CHO cell: DUKX B11 DHFR deficient CHO cells. (U.S. Patent No. 4,770,999, col. 9:11-13). An opposing party might argue that the invention as disclosed is limited to such DHFR-deficient CHO cells, which are particularly suited for the described gene amplification process using methotrexate. (U.S. Patent No. 4,770,999, col. 9:1-11).

VI. Other Allegations

The complaint does not allege indirect or willful infringement. It is an action for dissatisfaction with a decision from the Board of Patent Appeals and Interferences. (Compl. ¶1, ¶32).

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

  • A primary procedural question will be one of admissible evidence: Will the district court, conducting a de novo review under 35 U.S.C. § 146, permit ZymoGenetics to introduce new evidence and testimony that the USPTO Board allegedly refused to consider, as requested in the complaint? (Compl. ¶32, Prayer for Relief ¶A).
  • A central substantive issue will be the standard of patentability: The case will require the court to re-evaluate whether ZymoGenetics's patent application provided sufficient written description and enablement under 35 U.S.C. § 112 to support its claims, a question the Board decided adversely to ZymoGenetics. (Compl. ¶15, ¶32).
  • The ultimate question is one of priority of invention: While the complaint notes a favorable priority finding for its inventors on the "subject matter of the Count," the overall litigation will likely revisit the complete factual record to determine which party's inventors—ZymoGenetics's "Hagen et al." or the defendants' "Kaufman et al."—were the first to invent the patentable subject matter at issue. (Compl. ¶19).