Merck Sharp & Dohme Corp v. Pfizer Inc

1. Case Identification

• Patent #: 9,492,559
• Filed: September 20, 2017
• Petitioner(s): Merck Sharp & Dohme Corp.
• Patent Owner(s): Pfizer Inc.
• Challenged Claims: 11-15, 20-37

2. Patent Overview

• Title: Multivalent Pneumococcal Conjugate Vaccines
• Brief Description: The ’559 patent is directed to immunogenic compositions comprising a Streptococcus pneumoniae serotype 22F glycoconjugate. The technology aims to broaden vaccine coverage to include emerging serotypes not found in prior licensed vaccines like PREVNAR®, SYNFLORIX®, and PREVNAR 13®, thereby addressing an unmet medical need.

3. Grounds for Unpatentability

Ground 1: Obviousness over Merck 2011 and GSK 2008 - Claims 11-14, 23-33, and 35-37 are obvious over Merck 2011 in view of GSK 2008 and the general knowledge of a POSITA.

• Prior Art Relied Upon: Merck 2011 (WO 2011/100151) and GSK 2008 (WO 09/000825).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the combination of Merck 2011 and GSK 2008 rendered the challenged claims obvious. The sole independent claim requires an immunogenic composition with a serotype 22F glycoconjugate having a molecular weight between 1,000-12,500 kDa and a polysaccharide-to-protein ratio between 0.4-2. Petitioner asserted that Merck 2011 disclosed an immunogenic 15-valent vaccine containing a serotype 22F conjugate and taught polysaccharide-to-protein ratios (disclosing a final conjugate ratio of ~1.0) falling within the claimed range. While Merck 2011 did not specify the molecular weight, GSK 2008 disclosed adding serotype 22F to a multivalent vaccine and reported molecular weights for its ten other conjugates ranging from 1,303 to 9,572 kDa, squarely within the ’559 patent’s claimed range.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) developing a pneumococcal vaccine would have been motivated to combine the teachings of Merck 2011 and GSK 2008, as they were published by two leading vaccine manufacturers. Both references explicitly addressed the development of multivalent vaccines including the emerging serotype 22F.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success. GSK 2008 demonstrated that conjugates with molecular weights in the claimed range could be routinely produced and were immunogenic. Both Merck 2011 and GSK 2008 showed that their respective serotype 22F conjugates elicited functional antibody responses, confirming that the resulting combination would be immunogenic as claimed.

Ground 2: Obviousness of Syringe Claims - Claim 15 is obvious over Merck 2011, GSK 2008, and the ’787 Patent.

• Prior Art Relied Upon: Merck 2011 (WO 2011/100151), GSK 2008 (WO 09/000825), and the ’787 Patent (Patent 7,935,787).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the primary combination to challenge claim 15, which recites a syringe that is "siliconized or made of glass" filled with the composition. Petitioner argued that the ’787 patent, also owned by Pfizer, explicitly taught formulating polysaccharide-protein conjugate vaccines in siliconized glass syringes.
  • Motivation to Combine: The ’787 patent explained that using siliconized syringes lubricates the plunger and inhibits protein aggregation, improving syringeability. A POSITA formulating the vaccine of Merck/GSK would have been motivated to use this conventional and advantageous container-closure system.
  • Expectation of Success: Given that siliconized glass syringes were a standard and well-understood delivery vehicle for conjugate vaccines, a POSITA would have had a high expectation of success in packaging the immunogenic composition in such a container.

Ground 3: Obviousness of Combination Vaccine Claims - Claims 20-21 are obvious over Merck 2011, GSK 2008, and Obaro 2002.

• Prior Art Relied Upon: Merck 2011 (WO 2011/100151), GSK 2008 (WO 09/000825), and Obaro 2002 (a journal article on vaccine safety and immunogenicity).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground challenged claims 20-21, which add antigens from other pathogens (e.g., diphtheria, tetanus) to the base composition. Petitioner cited Obaro 2002, which reported the safety and immunogenicity of co-administering a 9-valent pneumococcal conjugate vaccine with a combination vaccine containing diphtheria toxoid, tetanus toxoid, whole cell pertussis, and H. influenzae type b antigens.
  • Motivation to Combine: A POSITA would have been motivated to combine the base pneumococcal vaccine with other common antigens to enhance protection and reduce the total number of injections for a patient, a well-known goal in vaccinology, particularly for infants. Obaro 2002 provided an explicit example of this being done safely and effectively.
  • Expectation of Success: The successful combination reported in Obaro 2002, coupled with the demonstrated immunogenicity of the serotype 22F conjugates in Merck/GSK, provided a strong basis for a POSITA to expect success in creating a safe and effective combination vaccine.

• Additional Grounds: Petitioner asserted additional obviousness challenges for claim 22 (combination with meningococcal conjugates) based on Sigurdardottir 2008 and for claim 34 (use in immunocompromised patients) based on MMWR 2012. These grounds relied on the same core Merck/GSK combination, with the additional references providing established motivations for creating combination therapies or for use in specific, well-defined patient populations.

4. Key Claim Construction Positions

• Petitioner argued that the term "immunogenic" in independent claim 1 should be construed to mean "elicits functional antibody against at least pneumococcus serotype 22F."
• This proposed construction was based on the prosecution history of the ’559 patent. To overcome a rejection over prior art that disclosed serotype 22F conjugates, the Patent Owner amended the claims to add molecular weight and protein ratio limitations. Crucially, the Patent Owner argued for patentability by pointing to data in the specification (Example 13) showing that conjugates with these properties "produced sera having opsonophagocytic activity" (OPA), which is a measure of functional antibodies. Petitioner contended that since the Patent Owner relied on the generation of functional antibodies to distinguish its invention, "immunogenic" must be limited to that specific functional outcome.

5. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 11-15 and 20-37 of the ’559 patent as unpatentable.