Pfizer Inc v. Biogen Inc

1. Case Identification

• Case #: IPR2017-01166
• Patent #: 8,329,172
• Filed: April 21, 2017
• Petitioner(s): Pfizer, Inc.
• Patent Owner(s): Biogen, Inc.
• Challenged Claims: 1

2. Patent Overview

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

3. Grounds for Unpatentability

Ground 1: Obviousness over Hochster I, Rituxan Label, and McNeil - Claim 1 is obvious over Hochster I in view of the Rituxan label and McNeil.

• Prior Art Relied Upon: Hochster I (a May 1998 abstract from an American Society of Clinical Oncology meeting), the Rituxan label (the FDA-approved product label from Nov. 1997), and McNeil (a Feb. 1998 news report in the Journal of the National Cancer Institute).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the prior art collectively disclosed every element of the claimed method. Hochster I, which was not considered during prosecution, disclosed a phase III clinical trial underway to treat LG-NHL with "CVP ± anti-CD20 maintenance," teaching the core combination of CVP induction therapy followed by maintenance with an anti-CD20 agent. The Rituxan label taught that rituximab was the only FDA-approved anti-CD20 agent at the time and disclosed the only recommended dosing regimen: four weekly infusions of 375 mg/m². Finally, McNeil disclosed the only known maintenance schedule for rituximab at the time: administration every six months for two years. Petitioner contended that combining these teachings rendered the single claim of the ’172 patent obvious.
  • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSA) would have been motivated to combine these references to arrive at the claimed invention. A POSA, starting with the CVP and anti-CD20 maintenance protocol disclosed in Hochster I, would have naturally selected rituximab as the anti-CD20 agent because it was the only one approved by the FDA for treating LG-NHL. The POSA would then have been motivated to use the specific dose (375 mg/m² weekly for four doses) from the Rituxan label as it was the only approved, clinically-proven, and recommended regimen. Likewise, the POSA would combine this with the maintenance schedule from McNeil (every six months for two years), as it was the only schedule for rituximab maintenance reported in the art. This motivation was strengthened by the Rituxan label's disclosure that B-cell recovery began approximately six months after treatment, providing a clear scientific rationale for the six-month dosing interval.
  • Expectation of Success: Petitioner asserted that a POSA would have had a reasonable expectation of success. The fact that Hochster I described an ongoing Phase III clinical trial—an advanced stage of human testing designed to secure regulatory approval—strongly indicated that the therapy was reasonably expected to be safe and effective. The individual components were all well-established: CVP was a standard first-line therapy, maintenance therapy was a known concept to extend remission, and rituximab was an FDA-approved drug with a known safety profile. Therefore, combining these known elements for their intended purposes would have been expected to succeed.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial would be inappropriate, particularly under 35 U.S.C. §325(d). It highlighted that a prior IPR on the ’172 patent (IPR2015-00418) was denied institution. However, Petitioner contended that the primary reference in the present petition, Hochster I, was not cited or considered in the earlier proceeding. Petitioner argued that Hochster I is a critical reference that expressly discloses the core combination of CVP induction followed by anti-CD20 maintenance, making the present challenge materially different and substantially stronger than the one previously denied by the Board.

5. Relief Requested

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