PTAB

IPR2016-00822

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 detecting nucleic acids. The core technology involves an array of single-stranded nucleic acids fixed or immobilized in a hybridizable form onto a non-porous solid support, such as a microtiter plate or glass slide.

3. Grounds for Unpatentability

Ground 1: Anticipation by Fish - Claims 17, 19, 25, 105, 106, 114, 116, 119, 128, 129, 150, 152, 178, 180, 186, and 187 are anticipated by Fish under 35 U.S.C. § 102(b).

  • Prior Art Relied Upon: Fish (a March 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 disclosed every limitation of the independent claims. Fish described using polyvinyl microtitration trays, which are non-porous solid supports, with a plurality of wells arranged in rows, constituting an "array." Fish further disclosed immobilizing "various single-stranded" DNA molecules to the wells using a poly-l-lysine (PLL) coating. Petitioner contended that while Fish did not explicitly state the immobilized DNA was in "hybridizable form," this property was necessarily inherent because the non-covalent PLL binding method would not prevent the DNA from being capable of Watson-Crick base pairing, a fact later confirmed by other publications.
    • Key Aspects: The argument for the "hybridizable form" limitation relied on inherency, supported by the Patent Owner's own prosecution arguments in related applications and other technical literature showing that PLL-immobilized DNA is capable of hybridization.

Ground 2: Obviousness over VPK and Metzgar - Claims 17, 19, 25, 105, 106, 114, 119, 120, 128, 129, 131, 150, 151, 152, 178, 180, 186, and 189 are obvious over VPK in view of Metzgar.

  • Prior Art Relied Upon: VPK (an October 1982 journal article on in situ hybridization) and Metzgar (Patent 5,572,892).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was predicated on Petitioner’s assertion that the challenged claims were not entitled to their purported 1983 priority date due to a lack of written description support for the term "non-porous solid support" in the priority application. This would make VPK, published in 1982, valid prior art. Petitioner argued VPK disclosed immobilizing chromosomes (containing various DNA sequences) onto non-porous glass slides treated with aminoalkylsilane, which rendered the DNA fixed and in a hybridizable form. Metzgar was cited for its disclosure of microscope glass slides having "depressions or wells on the top surface," teaching the claimed "array" structure.
    • Motivation to Combine: A POSITA would combine VPK's immobilization chemistry with Metzgar's multi-well slide format for the predictable purpose of analyzing multiple samples simultaneously on a single slide. This was a well-known and common laboratory practice to increase efficiency and throughput.
    • Expectation of Success: Petitioner asserted a high expectation of success, as the combination involved applying a known immobilization technique (VPK) to a standard, compatible substrate format (Metzgar) to achieve a predictable and advantageous result.

Ground 3: Obviousness over Noyes, VPK, Metzgar, and Ramachandran - Claims 113, 116, 130, 154, 185, and 187 are obvious over Noyes in view of VPK and further in view of Metzgar and Ramachandran.

  • Prior Art Relied Upon: Noyes (a 1975 journal article), VPK, Metzgar, and Ramachandran (a 1976 journal article).

  • Core Argument for this Ground:

    • Prior Art Mapping: This complex combination targeted dependent claims requiring specific features like covalent immobilization and the use of RNA. The base combination of VPK and Metzgar provided the non-porous array. Noyes was introduced for its teaching of covalently linking DNA and RNA to a support using diazotized aryl amine groups. Ramachandran supplied the missing link by teaching a method to convert the alkylamines on VPK's treated glass slides into the arylamines required for Noyes's chemistry.
    • Motivation to Combine: A POSITA seeking a more robust and permanent attachment of nucleic acids than the non-covalent methods of VPK or Fish would have been motivated to explore known covalent linking chemistries. Noyes provided such a chemistry. To apply Noyes's method to the glass slide system of VPK/Metzgar, a POSITA would have turned to a reference like Ramachandran, which taught the necessary chemical conversion of the surface amine groups.
    • Expectation of Success: Success would be expected, as the combination involved a series of predictable chemical modification steps to adapt a known covalent attachment method to a common laboratory substrate.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including grounds based on Fish in view of Metzgar, Sato, or Gilham, which relied on similar theories to substitute materials or add known features to the base system disclosed in Fish.

4. Key Claim Construction Positions

  • "Non-Porous Solid Support": Petitioner proposed this term be given its ordinary and customary meaning, which includes conventional laboratory equipment such as microtiter wells and glass slides. This was supported by the patent's specification and the Patent Owner's admissions during prosecution.
  • "Hybridizable form": Petitioner proposed this term be construed as "capable of binding through Watson-Crick base pairing." This construction was agreed upon by both parties in related district court litigation and is supported by the patent's description of hybridization.
  • "Array": Petitioner proposed this term be construed as "an orderly grouping or arrangement," consistent with its use in the specification (referring to an "array of depressions or wells") and constructions adopted in related litigation.