Pfizer Inc v. Biogen Inc

1. Case Identification

• Case #: IPR2018-00231
• Patent #: 9,504,744
• Filed: December 1, 2017
• Petitioner(s): Pfizer, Inc.
• Patent Owner(s): Biogen, Inc.
• Challenged Claims: 1-16

2. Patent Overview

• Title: Treatment of Diffuse Large-Cell Lymphoma with Anti-CD20 Antibody
• Brief Description: The ’744 patent discloses methods for treating diffuse large B-cell lymphoma (DLCL) in patients over 60 years old. The method involves administering an anti-CD20 antibody (rituximab) in combination with CHOP chemotherapy, and in some claims, further in combination with a transplantation regimen.

3. Grounds for Unpatentability

Ground 1: Obviousness over Core Therapy References - Claims 11-12 and 15-16 are obvious over Macedo, Meyer 1995, Link, Coiffier, and McNeil.

• Prior Art Relied Upon: Macedo (a 1994 clinical abstract), Meyer 1995 (a 1995 journal article), Link (a 1998 meeting proceeding), McNeil (a 1998 journal article), and Coiffier (a 1998 journal article).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the prior art disclosed all elements of the claimed therapy for the specified patient population. Meyer 1995 established that six to eight cycles of full-dose CHOP chemotherapy was the standard of care for DLCL patients over 60. Macedo disclosed a less toxic "mini-CHOP" regimen, also administered for six to eight cycles, that was effective in the same elderly population. Link taught that adding rituximab (at the claimed 375 mg/m² dose) to full-dose CHOP for DLCL patients improved response rates without increasing toxicity. McNeil specifically suggested that "CHOP plus the monoclonal antibody [rituximab]" was a promising alternative for patients over 60. Finally, Coiffier confirmed that rituximab was safe and effective in DLCL patients over 60 and recommended it be tested in combination with chemotherapy.
  • Motivation to Combine: A person of ordinary skill in the art (POSA) would combine these teachings to address the known problem of CHOP's toxicity in elderly patients. The prior art created a clear path to improve efficacy without adding toxicity by adding rituximab to either standard full-dose CHOP (for patients who could tolerate it) or to the less toxic mini-CHOP regimen taught by Macedo. The motivation for concurrent administration (required by claim 11) stemmed from the general knowledge of enhancing therapeutic benefit by overlapping drug half-lives and the practical desire to reduce patient hospital visits and costs.
  • Expectation of Success: A POSA would have a reasonable expectation of success based on Link's positive results showing improved efficacy with no added toxicity and Coiffier's safety data for rituximab in the target patient population.

Ground 2: Obviousness with Transplantation Regimen - Claims 1-10 and 13-14 are obvious over Macedo, Meyer 1995, Link, Coiffier, and McNeil in view of Armitage and Maloney.

• Prior Art Relied Upon: The references from Ground 1, plus Armitage (a 1995 book chapter) and Maloney (a 1997 journal article).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground addresses the same core therapy as Ground 1 but adds the limitation "in combination with a transplantation regimen." Petitioner asserted this combination was also obvious. Armitage taught that bone marrow transplantation was a well-known and safe "conventional therapy" for elderly DLCL patients (up to 70 years old) if initial chemotherapy failed. Maloney specifically taught that rituximab could be used with transplantation regimens because it "does not appear to impair marrow reserves," meaning it would not interfere with the cells needed for successful transplantation. Dependent claims specifying bone marrow involvement (claim 4) were obvious because Coiffier and Maloney both reported successful rituximab treatment in patients with such involvement.
  • Motivation to Combine: A POSA would be motivated to add a known salvage therapy (transplantation) to the rituximab/CHOP combination if a patient did not sufficiently respond to the initial treatment. Maloney provided an explicit rationale for adding rituximab to a transplantation regimen, noting its compatibility. The combination represented the logical application of a standard, sequential treatment paradigm: using an improved induction therapy (rituximab/CHOP) followed by a conventional salvage therapy (transplantation) if needed.
  • Expectation of Success: The expectation of success was high, as it involved combining an improved initial therapy with a standard-of-care salvage therapy that was known to be compatible with rituximab.

• Additional Grounds: Petitioner asserted additional obviousness challenges (Grounds III and IV) based on subsets of the references cited above. These grounds argued that the claims would have been obvious even without relying on Coiffier, thereby demonstrating obviousness based entirely on prior art available under 35 U.S.C. §102(b).

4. Key Claim Construction Positions

• "in combination with a transplantation regimen": Petitioner argued this phrase should be construed to include administering the anti-CD20 antibody and CHOP as an initial "induction" therapy before the actual collection or transplantation of stem cells. This interpretation is based on the patent's specification, which states rituximab can be administered at induction to improve transplant outcomes.
• "CHOP... chemotherapy": Petitioner asserted that a POSA would understand this term to encompass both "full-dose" CHOP and the reduced-dose "mini-CHOP" regimen, as both were known options for treating elderly DLCL patients.
• "concurrently": Based on the specification's definition of "simultaneously," Petitioner argued a POSA would understand "concurrently" to mean administration of rituximab and CHOP on the same day during the same hospital visit.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-16 of the ’744 patent as unpatentable under 35 U.S.C. §103.