PTAB

IPR2017-01168

Pfizer Inc v. Biogen Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Treatment of Diffuse Large-Cell Lymphoma with Anti-CD20 Antibody
  • Brief Description: The ’873 patent discloses a method for treating diffuse large B-cell lymphoma (DLCL) in patients older than 60. The method involves administering an anti-CD20 antibody (e.g., rituximab) and CHOP chemotherapy in combination with a stem cell transplantation regimen.

3. Grounds for Unpatentability

Ground 1: Obviousness over Moreau, Link, McNeil, and Maloney - Claims 1-5 are obvious over Moreau and Link in view of McNeil and/or Maloney.

  • Prior Art Relied Upon: Moreau (a 1998 journal article), Link (a 1998 meeting proceeding), McNeil (a 1998 journal article), and Maloney (a 1997 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the prior art collectively taught every element of the claimed method. Moreau disclosed a "conventional" therapy for patients over 60 with DLCL comprising a reduced-dose CHOP chemotherapy regimen followed by peripheral blood stem cell transplantation (PBSCT), establishing the core treatment framework for the claimed patient population. The only missing element was the administration of an anti-CD20 antibody. Link taught that adding rituximab (an anti-CD20 antibody) to CHOP chemotherapy for DLCL patients resulted in higher response rates without increasing toxicity compared to CHOP alone. Petitioner contended that combining Moreau's regimen for elderly patients with Link's teaching to add rituximab for improved, safe efficacy rendered the claimed invention obvious. Dependent claims 2-3 (chimeric antibody, rituximab) were allegedly disclosed by Maloney, and independent claim 5 (specifying rituximab) was argued to be obvious for the same reasons.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references to solve a known problem. Moreau's study showed only a 50% complete response rate, creating a clear need for a more effective therapy for elderly DLCL patients. Link provided the solution by demonstrating that adding rituximab to CHOP improved efficacy without additional toxicity, providing a strong motivation to add rituximab to the Moreau regimen. Furthermore, McNeil explicitly suggested combining CHOP with rituximab as an alternative for patients over 60, and Maloney recommended adding rituximab to chemotherapy and stem-cell transplant regimens because it did not impair marrow reserves.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because Link taught that the toxicity profile of rituximab did not overlap with that of CHOP, making the combination tolerable. The predictable nature of combining known therapeutic agents with known individual effects (improving efficacy without adding toxicity) supported this expectation.

Ground 2: Obviousness over Moreau, Link, McNeil, Maloney, and Coiffier - Claims 1-5 are obvious over Moreau and Link in view of McNeil and/or Maloney, and further in view of Coiffier.

  • Prior Art Relied Upon: Moreau (a 1998 journal article), Link (a 1998 meeting proceeding), McNeil (a 1998 journal article), Maloney (a 1997 journal article), and Coiffier (a 1998 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground reinforced the arguments from Ground 1 and specifically addressed claim 4, which requires that the lymphoma is "accompanied by bone marrow involvement." While Maloney taught that rituximab was effective in patients with bone marrow involvement, Petitioner argued that Coiffier provided even stronger evidence. Coiffier specifically studied rituximab in elderly patients (median age >62) with DLCL and confirmed its safety and efficacy. Crucially, Coiffier showed that nearly half (43%) of patients with bone marrow involvement responded effectively to rituximab treatment.
    • Motivation to Combine: Coiffier's direct teaching of rituximab's safety and efficacy in the specific claimed patient population (elderly with DLCL) and sub-population (those with bone marrow involvement) provided an independent and compelling motivation to add rituximab to a standard CHOP and stem cell therapy regimen like that disclosed in Moreau.
    • Expectation of Success: The positive clinical results reported in Coiffier for the exact patient group claimed in the patent would provide a POSITA with a very high expectation of success for the combination therapy, particularly for patients with bone marrow involvement as recited in claim 4.

4. Key Claim Construction Positions

  • Petitioner argued that the terms of the ’873 patent should be given their plain and ordinary meaning.
  • The phrase "in combination with stem cell transplantation" was argued to be broad, encompassing the administration of the anti-CD20 antibody (rituximab) at the "induction" stage of CHOP chemotherapy, even before the actual collection or transplantation of stem cells. This interpretation was asserted to be supported by the patent's specification.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-5 of the ’873 patent as unpatentable under 35 U.S.C. §103.