DCT

3:20-cv-01786

NantKwest Inc v. Fox Chase Cancer Center Foundation

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:20-cv-01786, S.D. Cal., 09/01/2021
  • Venue Allegations: Venue is based on Defendant’s principal place of business being located within the Southern District of California.
  • Core Dispute: Plaintiff alleges that its employee, Dr. Kerry Campbell, was a joint inventor of Defendant's patents related to genetically engineered NK-92 cells for cancer immunotherapy, and seeks correction of inventorship and a corresponding declaration of joint ownership.
  • Technical Context: The technology relates to the field of cellular immunotherapy, specifically the genetic modification of Natural Killer (NK) cells to enhance their cancer-fighting capabilities when used in combination with monoclonal antibody drugs.
  • Key Procedural History: The complaint states that this action originated as a cross-complaint filed by Plaintiff in a prior case. After the original claims in that case were remanded to state court, the parties were realigned, leaving Plaintiff's inventorship claims in federal court. Plaintiff also alleges it made repeated pre-suit requests to Defendant's predecessor to have the inventorship corrected, which were met with "cursory, non-substantive responses."

Case Timeline

Date Event
2013-11 Plaintiff alleges its employee, Dr. Campbell, began communications with a named inventor regarding vector design.
2014-04 Plaintiff alleges Dr. Campbell continued communications with another named inventor regarding plasmid design.
Late 2014 A Sponsored Research Agreement was executed between Plaintiff and Defendant's predecessor.
2015-03-27 Earliest Priority Date for '420, '921, and '550 Patents.
2016-03-25 International patent application filed, leading to the '420 Patent.
2019-08-15 U.S. patent application filed, leading to the '921 Patent.
2019-10-29 U.S. Patent No. 10,456,420 ('420 Patent) Issued.
2020-06-17 U.S. patent application filed, leading to the '550 Patent.
2020-08-11 U.S. Patent No. 10,736,921 ('921 Patent) Issued.
2021-05-11 U.S. Patent No. 11,000,550 ('550 Patent) Issued.
2021-09-01 Complaint Filing Date.

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

U.S. Patent No. 10,456,420 - “Genetically Modified NK-92 Cells and Monoclonal Antibodies for the Treatment of Cancer”

The Invention Explained

  • Problem Addressed: The patent addresses two key limitations of using the NK-92 cell line for cancer therapy. First, standard NK-92 cells lack the CD16 receptor, which prevents them from engaging in antibody-dependent cellular cytotoxicity (ADCC), a primary mechanism by which monoclonal antibody drugs kill cancer cells ('420 Patent, col. 1:41-52). Second, NK-92 cells require the cytokine Interleukin-2 (IL-2) for survival and growth, but systemic administration of IL-2 to patients can cause severe toxic side effects ('420 Patent, col. 14:35-43).
  • The Patented Solution: The invention describes genetically modifying NK-92 cells to solve both problems simultaneously. The cells are engineered to express the CD16 receptor, enabling them to perform ADCC. They are also engineered to express their own IL-2, making them self-sufficient. To avoid the toxicity of systemic IL-2, the engineered IL-2 is specifically targeted to remain within the cell's endoplasmic reticulum (ER), providing the necessary survival signal internally without being secreted ('420 Patent, col. 4:11-24; Abstract). The patent discloses a single plasmid expression vector containing the genetic code for both the CD16 protein and the ER-targeted IL-2, linked by an internal ribosome entry site (IRES) to ensure both are produced ('420 Patent, Claim 1; Fig. 1).
  • Technical Importance: This approach aims to create a more potent and safer "off-the-shelf" cell therapy that can synergize with existing monoclonal antibody treatments while eliminating the need for co-administration of toxic systemic cytokines ('420 Patent, col. 1:53-59).

Key Claims at a Glance

  • The complaint focuses on independent claim 1, which claims a method of treating cancer.
  • The essential elements of this claim are:
    • Administering a monoclonal antibody and genetically modified NK-92 cells.
    • The NK-92 cells are modified using a plasmid expression vector to stably express a specific high-affinity version of the CD16 polypeptide.
    • The cells also express Interleukin-2 (IL-2) that is targeted to the endoplasmic reticulum (ER).
    • The expression vector itself comprises a specific transgene structure: in the 5' to 3' direction, it contains a polynucleotide for CD16, an IRES, and a polynucleotide for the ER-targeted IL-2.

U.S. Patent No. 10,736,921 - “Genetically Modified NK-92 Cells and Monoclonal Antibodies for the Treatment of Cancer”

The Invention Explained

  • Problem Addressed: The '921 Patent addresses the same technical challenges as the '420 Patent: the inability of standard NK-92 cells to perform ADCC and the toxicity associated with the systemic IL-2 they require for survival ('921 Patent, col. 1:44-55; col. 3:19-24).
  • The Patented Solution: Rather than claiming a method of treatment, the '921 Patent claims the therapeutic product itself: a pharmaceutical composition containing the engineered NK-92 cells along with a monoclonal antibody ('921 Patent, Abstract). The core of the invention remains the genetic modification of the NK-92 cells using a bicistronic nucleic acid construct that co-expresses the high-affinity CD16 receptor and an ER-targeted IL-2, rendering the cells capable of ADCC and self-sufficient for growth signals ('921 Patent, Claim 1).
  • Technical Importance: By claiming the composition directly, the patent provides a distinct form of intellectual property protection covering the engineered cell product, complementing the method-of-use claims in the '420 Patent.

Key Claims at a Glance

  • The complaint discusses independent claim 1, which claims a pharmaceutical composition.
  • The essential elements of this claim are:
    • A composition comprising a population of engineered NK-92 cells and a monoclonal antibody.
    • The NK-92 cells are genetically modified to express a nucleic acid construct.
    • The construct encodes a CD16 polypeptide (with the high-affinity valine at position 158) and an IL-2 polypeptide targeted to the ER.
    • The construct is "bicistronic," meaning it is designed to produce both the CD16 and IL-2 proteins from a single transcript.

U.S. Patent No. 11,000,550 - “Genetically Modified NK-92 Cells and Monoclonal Antibodies for the Treatment of Cancer”

The Invention Explained

  • Technology Synopsis: This patent is a continuation of the application that led to the '921 Patent and claims similar subject matter. The claims focus on a composition of engineered NK-92 cells defined by a key functional characteristic: the engineered cell line "exhibits enhanced ADCC activity in combination with a monoclonal antibody" ('550 Patent, Claim 1; Compl. ¶36). This functionally-defined limitation distinguishes it from the prior patents, which focus more on the structural aspects of the genetic modification.
  • Accused Features: This is an inventorship, not an infringement, action. The complaint alleges that Plaintiff's employee, Dr. Campbell, was a joint inventor of the subject matter claimed in the '550 Patent (Compl. ¶40).

Key Claims at a Glance

  • Asserted Claims: The complaint discusses independent claim 1 (Compl. ¶36).

III. Analysis of Inventorship Allegations

No probative visual evidence provided in complaint.

The complaint does not allege patent infringement; rather, it alleges that Plaintiff’s employee, Dr. Kerry Campbell, was a joint inventor who was improperly omitted from the '420, '921, and '550 patents. The central legal test for inventorship is conception—the formation of a definite and permanent idea of the complete and operative invention in the mind of the inventor. The complaint alleges that Dr. Campbell conceived of and communicated to the named inventors the key features that define the patented technology (Compl. ¶¶ 21-24, 40).

The complaint specifically alleges that Dr. Campbell's inventive contributions included the conception of the core design of the expression vector used to modify the NK-92 cells (Compl. ¶¶ 22-24). These alleged contributions map directly onto limitations found in the patents' asserted claims, including:

  1. Targeting IL-2 to the Endoplasmic Reticulum (ER): The complaint alleges Dr. Campbell conceived of "ideas to target [IL-2] to the ER" to provide an internal survival signal without causing systemic toxicity (Compl. ¶24).
  2. The Bicistronic Vector Structure: The complaint alleges Dr. Campbell conceived of using a single vector to express both CD16 and the ER-targeted IL-2, including the specific structural arrangement of "a polynucleotide encoding the CD16 polypeptide, an IRES, and a polynucleotide encoding the IL-2 targeted to the ER" (Compl. ¶27).

The complaint alleges that these specific contributions were communicated to the named inventors in emails and as part of a collaboration for an SBIR grant in 2013 and 2014, prior to the patents' priority date (Compl. ¶¶ 22-24). To underscore the significance of these alleged contributions, the complaint asserts that the specific vector structure allegedly conceived by Dr. Campbell was the very feature added by amendment during prosecution to overcome a patent office rejection, leading directly to the allowance of the claims of the '420 Patent (Compl. ¶27). The complaint further alleges that this same bicistronic construct is central to the patentable subject matter of the '921 and '550 Patents (Compl. ¶38).

IV. Ownership Claims

In addition to seeking correction of inventorship under 35 U.S.C. § 256 (First, Second, and Third Causes of Action), the complaint seeks a declaratory judgment of joint ownership of the '420, '921, and '550 patents (Fourth, Fifth, and Sixth Causes of Action) (Compl. ¶¶ 45-71). The basis for this claim is the allegation that Dr. Campbell, as an employee of Plaintiff, was under a contractual obligation to assign his inventions to Plaintiff (Compl. ¶46). If the court finds Dr. Campbell to be a joint inventor, Plaintiff, as his assignee, would become a joint owner of the patents. Under U.S. patent law, a joint owner can exploit a patent without the consent of, or an accounting to, other co-owners.

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

The resolution of this dispute does not turn on claim construction or infringement, but on questions of fact and law regarding inventorship. The central issues for the court will likely be:

  • A core legal question will be one of inventive contribution: does the evidence cited in the complaint, such as emails and research proposals, demonstrate that Dr. Campbell contributed to the "conception"—the definite and permanent idea of the complete invention—of the subject matter as ultimately claimed? The analysis will likely focus on whether his alleged contributions went beyond providing general knowledge or executing the ideas of others and rose to the level of conceiving a specific, claimed element.
  • A key evidentiary question will be one of corroboration: can Plaintiff provide sufficient independent evidence to corroborate Dr. Campbell’s testimony regarding the timing and substance of his alleged conception? Under patent law, an inventor’s testimony must be supported by corroborating evidence, and the court will need to determine if the documents referenced in the complaint satisfy this legal requirement.