PTAB

IPR2018-00285

Pfizer Inc v. Biogen Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Combination Therapies for B-Cell Lymphomas Comprising Administration of Anti-CD20 Antibody
  • Brief Description: The ’172 patent’s sole claim is directed to a method of treating low-grade B-cell non-Hodgkin's lymphoma (LG-NHL) by administering chemotherapy consisting of CVP therapy (cyclophosphamide, vincristine, and prednisone), followed by a specific rituximab maintenance therapy regimen for patients who respond to the initial CVP therapy.

3. Grounds for Unpatentability

Ground 1: Obviousness over Hochster I, Maloney, and McNeil - Claim 1

  • Prior Art Relied Upon: Hochster I (a May 1998 abstract from an American Society of Clinical Oncology meeting), Maloney (a September 1997 journal article), and McNeil (a February 1998 news report).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the combination of these references disclosed every limitation of claim 1. Hochster I taught the core method of treating LG-NHL with CVP induction chemotherapy followed by “anti-CD20 maintenance” therapy, based on its disclosure of an ongoing Phase III clinical trial. At the time, rituximab was the only FDA-approved anti-CD20 agent. Maloney taught administering rituximab at a dose of 375 mg/m² in four weekly infusions, a regimen proven safe and effective in Phase II trials for LG-NHL. McNeil disclosed the only known schedule for rituximab maintenance therapy: every 6 months for 2 years, based on a clinical trial for intermediate-grade NHL.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSA) seeking to implement the “anti-CD20 maintenance” therapy disclosed in Hochster I would have been motivated to select rituximab, as it was the only approved anti-CD20 agent. The POSA would then logically use the clinically proven dose and administration schedule for rituximab taught by Maloney (375 mg/m², four weekly infusions). To determine the maintenance frequency and duration, the POSA would have been motivated to adopt the only schedule known for rituximab maintenance therapy, as taught by McNeil (every 6 months for 2 years). This 6-month frequency was further supported by Maloney’s teaching that B-cell recovery begins approximately six months after treatment, providing a scientific rationale for re-administration at that interval.
    • Expectation of Success: A POSA would have had a reasonable expectation of success because Hochster I described an ongoing Phase III clinical trial, which is an advanced stage of testing that presumes a high likelihood of therapeutic utility. Maloney further provided evidence of rituximab’s safety and efficacy at the specific claimed dose.

Ground 2: Obviousness over Hochster I, the Rituxan™ label, and McNeil - Claim 1

  • Prior Art Relied Upon: Hochster I (a May 1998 abstract), the Rituxan™ label (1997/1998 versions from the FDA, Physician's Desk Reference, and Genentech's website), and McNeil (a February 1998 news report).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented a substantially identical argument to Ground 1, substituting the Rituxan™ label for Maloney. Petitioner asserted that the Rituxan™ label, as the official prescribing information, served the same purpose as Maloney: it confirmed rituximab is a monoclonal antibody directed against the CD20 antigen and taught the single FDA-approved dosing regimen of 375 mg/m² given as an IV infusion once weekly for four doses. The label also noted that B-cell recovery began approximately six months after treatment, reinforcing the motivation to adopt McNeil's 6-month re-treatment interval.
    • Motivation to Combine: The motivation was identical to Ground 1. A POSA implementing Hochster I's method would combine it with rituximab, and would have been motivated to use, or at least try, the only FDA-approved dosing regimen as specified on the Rituxan™ label. The combination with McNeil’s known maintenance schedule would have been a logical and predictable design choice.
    • Expectation of Success: The expectation of success was the same as in Ground 1, further supported by the fact that the Rituxan™ label described the only FDA-approved and clinically successful regimen for the drug.

4. Key Claim Construction Positions

  • Petitioner stated it did not contest the Patent Trial and Appeal Board's constructions from a prior IPR (IPR2015-00418) for key claim terms.
  • These terms included "chemotherapy consisting of CVP therapy" (construed as a combination of cyclophosphamide, vincristine, and prednisone, to the exclusion of other agents) and "CVP therapy to which the patient responds, followed by rituximab maintenance therapy" (requiring a patient response before maintenance therapy begins).

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial would be inappropriate because this petition was a "follow-on" petition filed solely to cure a procedural deficiency identified in a prior petition (IPR2017-01166).
  • The prior petition was denied institution not on the merits, but because the Board found insufficient evidence that the Rituxan™ label was a publicly accessible printed publication.
  • This petition cured that defect by substituting the Rituxan™ label with Maloney (in Ground 1), an indisputably public prior art document with the same relevant teachings, and by providing additional evidence of the Rituxan™ label's public accessibility (for Ground 2). Petitioner cited Board precedent allowing such corrective follow-on petitions that do not rely on the Board's prior decision as a "roadmap" to attack the merits.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claim 1 of the ’172 patent as unpatentable under 35 U.S.C. §103.