PTAB

IPR2017-02132

Merck Sharp & Dohme Corp v. Pfizer Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Immunogenic Compositions
  • Brief Description: The ’559 patent discloses immunogenic compositions comprising a Streptococcus pneumoniae serotype 22F glycoconjugate. The invention is aimed at broadening the coverage of existing pneumococcal conjugate vaccines by including serotypes not found in prior commercial vaccines like Prevnar 13®, with the serotype 22F conjugate defined by specific molecular weight and polysaccharide-to-protein ratio ranges.

3. Grounds for Unpatentability

Ground 1: Obviousness over Merck 2011 and Pfizer 2012 - Claims 1, 5-10, 16-19, 39, 41-42 and 45 are obvious over Merck 2011 in view of Pfizer 2012

  • Prior Art Relied Upon: Merck 2011 (International Publication No. WO 2011/100151) and Pfizer 2012 (a 2012 scientific symposium presentation).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Merck 2011 discloses all limitations of independent claim 1 except for the specific molecular weight range. Merck 2011 teaches a 15-valent immunogenic pneumococcal conjugate vaccine that includes serotype 22F conjugated to a CRM197 carrier protein. It also discloses a polysaccharide-to-protein ratio of approximately 1:1, which falls within the claimed range of 0.4 to 2. The only missing element, the molecular weight, was supplied by Pfizer 2012. This presentation, given by the Patent Owner, discloses that the "Typical Mass (kDa)" for glycoconjugates is "500 to 5000 [kDa]," a range that substantially overlaps with the claimed range of 1,000 to 12,500 kDa. Petitioner asserted that this overlap establishes a prima facie case of obviousness. Dependent claims were argued to recite standard, well-known features of such vaccines, also disclosed in Merck 2011.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) developing a next-generation pneumococcal vaccine would have been motivated to combine the teachings. Merck 2011 provided a promising 15-valent vaccine candidate including the emerging serotype 22F. Pfizer 2012 provided the Patent Owner's own guidance on typical, and thus desirable, molecular weight ranges for such glycoconjugates. A POSITA would combine these teachings to optimize the vaccine composition using known parameters for achieving immunogenicity.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because applying a typical molecular weight range to a known conjugate composition involved only routine experimentation. Merck 2011 already disclosed standard reductive amination chemistry to create the conjugates, and it was well-known that the final molecular weight could be controlled by routine variation of conjugation conditions.

Ground 2: Obviousness over Merck 2011, Pfizer 2012, and PVP 2013 - Claims 2, 40 and 43 are obvious over the combination of Merck 2011, Pfizer 2012, and PVP 2013

  • Prior Art Relied Upon: Merck 2011, Pfizer 2012, and PVP 2013 (a revision to Japan's "Minimum Requirements for Biological Products").
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground adds PVP 2013 to the primary combination to address claims reciting a minimum acetate content. PVP 2013 specifies that for a pneumococcal polysaccharide vaccine, serotype 22F must contain an O-acetyl to polysaccharide molar ratio of "0.5 - 1.5". This range inherently satisfies the claimed limitation of "at least 0.1 mM acetate per mM polysaccharide."
    • Motivation to Combine: A POSITA would consult a standard like PVP 2013 when designing a vaccine. Because O-acetyl groups were known to contribute to the immunogenicity of polysaccharides, a POSITA would be motivated to preserve the required acetate levels taught by PVP 2013 when creating the conjugate vaccine of Merck 2011 and Pfizer 2012 to ensure an effective immune response.

Ground 3: Obviousness over Merck 2011, Pfizer 2012, and GSK 2008 - Claims 3-4, 39 and 45 are obvious over the combination of Merck 2011, Pfizer 2012, and GSK 2008

  • Prior Art Relied Upon: Merck 2011, Pfizer 2012, and GSK 2008 (International Publication No. WO 09/000825).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground adds GSK 2008 to address claims requiring additional serotypes (15B, 33F, etc.), limitations on free polysaccharide, and specific polysaccharide molecular weights. GSK 2008 discloses multivalent conjugate compositions containing serotypes 22F, 15B, and 33F, among others. It also teaches that its serotype 22F conjugates contained less than 12% free polysaccharide, well below the claimed limit of "less than about 50%," and disclosed serotype 22F polysaccharide sizes between 50 and 800 kDa, overlapping the claimed range in claim 45.
    • Motivation to Combine: GSK 2008 demonstrated the feasibility of creating multivalent vaccines with the specific serotypes claimed. A POSITA seeking to create the broadest possible effective vaccine would be motivated to include these known, prevalent serotypes taught by GSK 2008 into the base composition from Merck 2011. The low level of free polysaccharide was a known goal for improving vaccine efficacy and consistency.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge against claims 38 and 44 over Merck 2011, Pfizer 2012, and Hsieh 2000 (a 2000 journal article), which provided teachings on molecular size distribution and degree of conjugation for pneumococcal vaccines.

4. Key Claim Construction Positions

  • Petitioner argued that the term "immunogenic," which appears in the preamble of claim 1, required construction and should be treated as a claim limitation.
  • Based on the patent’s specification and the Patent Owner’s arguments during prosecution to overcome prior art, Petitioner proposed that "immunogenic" be construed to mean "elicits functional antibody against at least pneumococcus serotype 22F." The Patent Owner had relied on data showing opsonophagocytic activity (a measure of functional antibody) to distinguish its invention from prior art that disclosed serotype 22F conjugates without such immunogenicity data.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-10, 16-19, and 38-45 of the ’559 patent as unpatentable.