PTAB

IPR2017-02126

Pfizer Inc v. Genentech Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Treatment of Hematological Malignancies Associated with Circulating Tumor Cells Using Chimeric Anti-CD20 Antibody
  • Brief Description: The ’612 patent discloses methods for treating chronic lymphocytic leukemia (CLL) in human patients. The methods involve administering an effective amount of a non-radiolabeled anti-CD20 antibody (rituximab), either as a monotherapy or combined with chemotherapy.

3. Grounds for Unpatentability

Ground 1: Claims 1-13, 15-22, 58, and 60 are obvious over Maloney 1994, Maloney (Sept.) 1997, and the Genentech Press Release.

  • Prior Art Relied Upon: Maloney 1994 (a 1994 publication in Blood), Maloney (Sept.) 1997 (a 1997 publication in Blood), and the Genentech Press Release (a 1995 press release).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the prior art disclosed all elements of the single-agent therapy claims. Maloney 1994 taught that rituximab was a promising therapy for non-Hodgkin's lymphoma (NHL), another B-cell cancer, by depleting CD20-expressing B-cells. It disclosed a safe and effective dose range (10 mg/m² to 500 mg/m²) that encompasses the claimed doses and suggested extending studies to patients with "more extensive disease," which a person of ordinary skill in the art (POSITA) would understand to include CLL. Furthermore, the Genentech Press Release, issued by the Patent Owner, explicitly announced plans to conduct clinical trials of rituximab for treating CLL. Petitioner also asserted that Maloney 1994 taught the negative claim limitations by disparaging the use of radiolabeled antibodies in favor of "naked" antibodies like rituximab.
    • Motivation to Combine: A POSITA would combine these references to apply a therapy shown to be safe and effective for one B-cell cancer (NHL) to a similar, albeit more extensive, B-cell cancer (CLL). The Patent Owner's own 1995 press release announcing clinical trials for this exact purpose provided a powerful motivation for a POSITA to pursue this therapeutic strategy.
    • Expectation of Success: The public disclosure by the Patent Owner that it was "planning additional studies" with rituximab to treat CLL based on "encouraging results" in NHL provided a POSITA with a strong reasonable expectation of success.

Ground 2: Claims 23-35, 37-45, and 59 are obvious over the Maloney References, and the Genentech Press Release.

  • Prior Art Relied Upon: Maloney 1994, Maloney (Sept.) 1997, Maloney (Oct.) 1997 (a 1997 publication in Journal of Clinical Oncology), and the Genentech Press Release.
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addresses claims for combination therapy. Petitioner contended that, in addition to the teachings supporting Ground 1, the Maloney references from 1997 made the combination of rituximab with chemotherapy obvious. Maloney (Oct.) 1997 taught that rituximab "increases sensitivity to the cytotoxic effect of chemotherapy/toxins in some resistant human lymphoma cell lines," providing a clear scientific rationale for a synergistic effect. Maloney (Sept.) 1997 explicitly suggested investigating rituximab in "combination with or after standard chemotherapy" for B-cell histologies like CLL.
    • Motivation to Combine: A POSITA would have been motivated to combine rituximab with chemotherapy to improve treatment efficacy, a common strategy in oncology. The rationale that rituximab could sensitize tumor cells to chemotherapy, thereby creating a more powerful, multi-pronged attack on the cancer, would have driven a POSITA to explore this combination, especially for a high tumor-burden disease like CLL where monotherapy might be insufficient.

Ground 3: Claims 46-57 are obvious over the Maloney References, the Genentech Press Release, and Kipps.

  • Prior Art Relied Upon: Maloney 1994, Maloney (Sept.) 1997, Maloney (Oct.) 1997, the Genentech Press Release, and Kipps (a 1995 textbook chapter in Williams Hematology).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground targets claims reciting specific chemotherapeutic agents. Petitioner argued that while the Maloney references and the Genentech Press Release established the obviousness of a general rituximab-chemotherapy combination, the Kipps textbook reference identified the specific claimed agents as the standard of care for treating CLL. Kipps disclosed that agents such as chlorambucil, cyclophosphamide, COP, CHOP, and fludarabine were well-known and effective treatments for CLL.
    • Motivation to Combine: The motivation was to implement the obvious combination therapy from Ground 2 using the known, established, and effective chemotherapeutic agents for CLL. A POSITA would naturally and predictably combine the promising new agent (rituximab) with the existing gold-standard chemotherapies for the target disease, as identified in a standard textbook like Kipps, to create the best possible treatment regimen.

4. Key Claim Construction Positions

  • Petitioner addressed the disputed term "amount effective to treat the CLL." Petitioner noted that while it proposes a broader construction, the obviousness analysis holds even under the Patent Owner's narrower proposed construction of "providing a positive clinical benefit to the chronic lymphocytic leukemia patient."
  • Petitioner argued that because the prior art taught that rituximab reduces the number of circulating tumor cells in B-cell cancers, a POSITA would have reasonably expected that administering rituximab to a CLL patient would result in such a reduction, which in turn would be expected to provide a positive clinical benefit.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-13, 15-35, and 37-60 of Patent 7,682,612 as unpatentable under 35 U.S.C. §103.