PTAB

IPR2016-00233

Roche Diagnostics Operations Inc v. Abbott Laboratories

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1. Case Identification

2. Patent Overview

  • Title: Diagnostic Test for Vitamin B12
  • Brief Description: The ’369 patent describes methods for producing recombinant porcine intrinsic factor (pIF). The core of the invention is the isolation of a nucleic acid sequence that encodes pIF, which is then used in standard recombinant protein expression systems.

3. Grounds for Unpatentability

Ground 1: Claims 7 and 11 are obvious over Hewitt in view of Kuemmerle and Sambrook 2001.

  • Prior Art Relied Upon: Hewitt (a 1991 journal article in Genomics), Kuemmerle (a 1992 journal article in Clinical Chemistry), and Sambrook 2001 (Molecular Cloning: A Laboratory Manual).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the alleged inventive step of the challenged claims—isolating a nucleic acid sequence for pIF—was obvious. Hewitt taught the successful cloning and sequencing of human intrinsic factor (IF) by using known rat IF cDNA as a probe, demonstrating the feasibility of cross-species gene isolation. Human IF shares 81% amino acid identity with the claimed pIF sequence (SEQ ID NO:9). Kuemmerle established that native pIF was the "gold standard" for use in vitamin B12 assays but suffered from purification difficulties and assay interferences. The remaining method steps of the claims—constructing a vector and expressing the protein in a host cell—were admittedly standard, well-known molecular biology techniques, as detailed in the Sambrook 2001 laboratory manual. Claim 11 differs from claim 7 only by requiring the isolation of a "complementary" nucleic acid, a routine step in molecular cloning also taught by Hewitt and Sambrook 2001.
    • Motivation to Combine: A POSITA would combine these references to solve a known problem. Kuemmerle highlighted the need for a reliable source of pIF for B12 assays, as isolating native pIF was expensive, tedious, and resulted in impure protein that caused assay interferences. Hewitt provided a clear roadmap for isolating a target species' IF gene (porcine) by using a known homologous sequence from another species (human, rat, or mouse). A POSITA was therefore motivated to apply the cloning strategy from Hewitt to the specific problem of producing recombinant pIF to overcome the drawbacks of native pIF described in Kuemmerle, using the standard methods outlined in Sambrook 2001.
    • Expectation of Success: A POSITA would have a high expectation of success. Hewitt successfully isolated human IF using a rat probe despite only ~80% sequence identity, demonstrating the principle's viability across species. Given the known conservation of the IF gene and the high sequence identity between human and porcine IF (81%), a POSITA would reasonably expect to isolate the porcine gene using the human sequence as a basis for designing probes or primers. Sambrook 2001 provided detailed protocols and troubleshooting guides for the standard techniques involved, further bolstering the expectation of success.

Ground 2: Claims 7 and 11 are obvious over Dieckgraefe in view of Kuemmerle and Sambrook 2001.

  • Prior Art Relied Upon: Dieckgraefe (a 1988 journal article in Proc. Natl. Acad. Sci. USA), Kuemmerle (a 1992 journal article in Clinical Chemistry), and Sambrook 2001 (Molecular Cloning: A Laboratory Manual).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented an alternative to Hewitt. Dieckgraefe taught the isolation and structural characterization of a cDNA clone encoding rat IF. Like Hewitt, Dieckgraefe also noted that the IF structure appears to be conserved among species, with antiserum against human IF recognizing IF in pigs. Dieckgraefe thus provided another example of a known IF sequence that a POSITA could use as a starting point to isolate the porcine equivalent. The roles of Kuemmerle (establishing the need for recombinant pIF) and Sambrook 2001 (providing the standard methods) were identical to their roles in Ground 1.
    • Motivation to Combine: The motivation was the same as in Ground 1: to produce a recombinant version of the "gold standard" pIF to overcome the known problems of cost, purity, and assay interference associated with the native protein. Dieckgraefe provided the knowledge of a conserved IF gene and a sequenced rat IF that could be leveraged to achieve this goal.
    • Expectation of Success: The expectation of success was similarly high. Dieckgraefe demonstrated successful isolation of the full-length rat IF gene and noted the cross-species conservation. A POSITA would reasonably expect that the methods used in Dieckgraefe, combined with the general knowledge and techniques in Sambrook 2001, could be successfully applied to isolate the homologous porcine gene.

4. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 7 and 11 of Patent 7,932,369 as unpatentable under 35 U.S.C. §103.