PTAB

IPR2016-00820

Hologic Inc v. Enzo Life Sciences Inc

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Key Events
Petition

1. Case Identification

2. Patent Overview

  • Title: System, Array and Non-Porous Solid Support Comprising Fixed or Immobilized Nucleic Acids
  • Brief Description: The ’197 patent discloses systems and methods for attaching single-stranded nucleic acids to a non-porous solid support, such as glass or plastic. The attachment is achieved via specific chemical functional groups—amines, hydroxyls, or epoxides—present on the support's surface, rendering the nucleic acids fixed in a hybridizable form.

3. Grounds for Unpatentability

Ground 1: Anticipation by Fish - Claims 1, 6, 8, 9, 12-16, 27, and numerous dependent claims are anticipated by Fish under 35 U.S.C. § 102(b).

  • Prior Art Relied Upon: Fish (a 1981 journal article titled "A Sensitive Solid Phase Microradioimmunoassay For Anti-Double Stranded DNA Antibodies").
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Fish discloses every limitation of the independent claims. Fish described using polyvinyl microtitration trays (a non-porous plastic support) coated with poly-L-lysine (PLL), which provides amine groups on the surface. Fish then immobilized single-stranded DNA (ssDNA) onto these PLL-coated wells. Petitioner contended that the immobilized ssDNA is necessarily "in hybridizable form," even though Fish did not perform a hybridization step. The argument asserted that the non-covalent ionic attachment method used in Fish inherently leaves the ssDNA capable of Watson-Crick base pairing.
    • Key Aspects: This ground’s success hinges on the argument that the "hybridizable form" limitation is inherently disclosed by Fish.

Ground 2: Anticipation by VPK - Claims 1, 6, 8, 9, 12-15, 27, and numerous dependent claims are anticipated by VPK under 35 U.S.C. § 102(b).

  • Prior Art Relied Upon: VPK (a 1982 journal article by Van Prooijen-Knegt et al. on in situ hybridization).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground is contingent on the success of Petitioner’s argument regarding the patent's priority date (see Section 5). Assuming VPK is valid prior art, Petitioner argued it anticipates the claims. VPK disclosed treating non-porous glass microscope slides with aminoalkylsilane to provide amine groups on the surface. VPK then fixed chromosomal DNA to the slides, denatured it into single strands, and performed in situ hybridization with complementary RNA. This process explicitly demonstrates fixing ssDNA to a non-porous support via amines in a form that is proven to be hybridizable, thus meeting all limitations of the independent claims.
    • Key Aspects: This ground is predicated on successfully challenging the ’197 patent’s claim to its 1983 priority date, which would make the 1982 VPK publication anticipatory prior art.

Ground 3: Obviousness over Fish in view of Gilham - Claims 38, 78, and 218 are obvious over Fish in view of Gilham under 35 U.S.C. § 103.

  • Prior Art Relied Upon: Fish (1981 journal article) and Gilham (a 1974 publication on immobilized polynucleotides).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground addressed dependent claims requiring that the fixation of nucleic acids be covalent. Petitioner argued Fish taught the foundational system: a non-porous support with amine groups for non-covalently immobilizing nucleic acids. Gilham taught specific chemistries for covalently linking RNA to solid supports containing amine groups.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Gilham’s covalent binding chemistry with Fish’s convenient non-porous support system. The motivation was to create a more robust and stable attachment of the nucleic acid to the substrate, a well-known benefit of covalent bonding over non-covalent interactions.
    • Expectation of Success: A POSITA would have a high expectation of success because both references involve binding nucleic acids to amine-functionalized surfaces. The combination represented a predictable application of known techniques to achieve a predictable improvement.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims reciting RNA instead of DNA would have been obvious over Fish (as RNA and DNA have similar properties for this type of binding), and that claims reciting specific support structures like wells or depressions would have been obvious over VPK in view of Metzgar (which taught microscope slides with wells). Petitioner also presented an obviousness ground combining VPK, Noyes, and Ramachandran to teach covalent binding on glass slides.

4. Key Claim Construction Positions

  • "Non-Porous Solid Support": Petitioner argued this term should be given its ordinary and customary meaning, which would encompass conventional laboratory items such as the plastic microtiter wells disclosed in Fish and the glass microscope slides disclosed in VPK. This construction is crucial for applying the prior art directly to the claims.
  • "Hybridizable form": Petitioner construed this term to mean "capable of binding through Watson-Crick base pairing." This construction is essential for the anticipation argument over Fish, which immobilized ssDNA but did not perform a hybridization assay. The construction supports the inherency argument that the DNA, by virtue of its immobilization method, was capable of hybridization.

5. Key Technical Contentions (Beyond Claim Construction)

  • Priority Date Challenge: A central technical contention was that the ’197 patent is not entitled to its claimed priority date of January 27, 1983. Petitioner argued the 1983 parent application fails the written description requirement of 35 U.S.C. §112 because it does not disclose or mention the claim element "non-porous solid support." The petition asserted that merely disclosing a few species (e.g., glass plates, polystyrene plates) that are in fact non-porous is insufficient to provide written description support for the entire genus of "non-porous" substrates. This would push the claims' effective filing date to that of the 1985 continuation-in-part (CIP) application where the term was first introduced, thereby making VPK (published in 1982) an anticipatory reference under §102(b).

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of all challenged claims as unpatentable.