Pfizer Inc v. Genentech Inc

1. Case Identification

• Patent #: 7,846,441
• Filed: October 3, 2017
• Petitioner(s): Pfizer Inc.
• Patent Owner(s): Genentech, Inc.
• Challenged Claims: 1-14

2. Patent Overview

• Title: Treatment with Anti-ErbB2 Antibodies
• Brief Description: The ’441 patent discloses methods for treating a human patient with a malignant, progressing, HER2-overexpressing tumor. The claimed method comprises administering a combination of an anti-ErbB2 antibody (e.g., Herceptin) and a taxoid (e.g., paclitaxel) in the absence of an anthracycline derivative.

3. Grounds for Unpatentability

Ground 1: Obviousness over Lottery in view of Hayes, Baselga '96, and Gelmon - Claims 1-14 are obvious over Lottery in view of Hayes and/or Baselga '96, and Gelmon.

• Prior Art Relied Upon: Lottery (LA Times article, Aug. 3, 1996), Hayes (J. CLIN. ONCOL., Mar. 1996), Baselga '96 (J. CLIN. ONCOL., Mar. 1996), and Gelmon (J. CLIN. ONCOL., Apr. 1, 1996).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Lottery, a newspaper article published over a year before the patent's priority date, discloses all elements of the challenged claims. Lottery described an ongoing clinical trial at UCLA treating HER2-overexpressing breast cancer patients with a combination of "taxol" (a taxoid) and Genentech's "HER2 antibody." The trial design described two arms—"taxol plus antibody" versus "just taxol"—which inherently teaches the claimed limitation "in the absence of an anthracycline derivative," as anthracyclines were not mentioned as part of the regimen. Petitioner asserted a POSITA would have known the "HER2 antibody" was the humanized 4D5 anti-ErbB2 antibody of the claims, a fact confirmed by Hayes and Baselga '96, which Lottery references.
  • Motivation to Combine: The primary motivation was manifest, as Lottery reported the combination was already being tested in human clinical trials to "boost the effectiveness of taxol." Further, Gelmon provided a strong rationale for avoiding anthracyclines due to their known cumulative cardiotoxicity and the high likelihood that metastatic breast cancer patients had received prior anthracycline treatment, making them ineligible or at high risk for further treatment with that class of drug.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success because a major clinical trial, as reported in Lottery, would not have commenced without promising preclinical data and a belief in its potential efficacy and safety. The article's report of "very promising" early results and tumor shrinkage would have reinforced this expectation.

Ground 2: Obviousness over Baselga '96 in view of Baselga '94 and Gelmon - Claims 1-14 are obvious over Baselga '96 in view of Baselga '94 and Gelmon.

• Prior Art Relied Upon: Baselga '96 (J. CLIN. ONCOL., Mar. 1996), Baselga '94 (PROC. AM. SOC. CLIN. ONCOL., Mar. 1994), and Gelmon (J. CLIN. ONCOL., Apr. 1, 1996).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Baselga '96, which describes a Phase II trial of rhuMAb HER2, explicitly notes that preclinical studies showed the antibody "markedly potentiated the antitumor effects" of agents including paclitaxel, and that "clinical trials of such combination therapy [were] in progress." This statement would have directed a POSITA to Baselga '94, which details these preclinical results. Baselga '94 discloses testing the antibody with either paclitaxel or an anthracycline (doxorubicin), but not both together, thereby teaching the claimed combination "in the absence of an anthracycline derivative."
  • Motivation to Combine: The motivation was explicitly provided by Baselga '96 itself, which pointed to the successful preclinical synergy with paclitaxel reported in Baselga '94. The combination in Baselga '94 achieved 93% tumor growth inhibition without increasing toxicity, far superior to the 70% inhibition from the antibody/doxorubicin combination. Gelmon again supplies the clinical motivation to pursue a non-anthracycline option for patients with prior exposure.
  • Expectation of Success: The compelling preclinical data in Baselga '94, showing significant synergistic effects without increased toxicity, created a strong expectation that the combination would be successful in the human clinical trials that both Baselga '94 and Baselga '96 stated were underway.

4. Key Claim Construction Positions

• "in the absence of an anthracycline derivative": Petitioner argued this term should be given its plain meaning of "not together with an anthracycline derivative." This construction means the claim only excludes a simultaneous three-drug regimen (antibody + taxoid + anthracycline). This interpretation is critical because prior art like Baselga '94 discloses treatment arms with an antibody plus paclitaxel, and separate arms with an antibody plus an anthracycline, which would fall within the scope of the claims under Petitioner's proposed construction. Petitioner contended that Patent Owner's contrary position—requiring active "avoidance" of anthracyclines—improperly imports a non-existent positive limitation and contradicts positions Patent Owner took during prosecution.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that the Board should not exercise its discretion to deny institution under 35 U.S.C. §314 or §325(d). The petition asserted that Ground 1 is based on Lottery, a non-scientific newspaper article that was not previously raised and was reasonably not discovered during prior searches focused on scientific literature. It argued that Ground 2, while containing overlapping art from a prior petition, was necessary to address Patent Owner's "newly-minted" claim construction requiring "avoidance" of anthracyclines, an argument not previously at issue. Petitioner also noted that the Board had already instituted review on a related patent (’549 patent) on substantively identical grounds, suggesting the challenged claims are likely unpatentable and that institution serves the public interest.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-14 of Patent 7,846,441 as unpatentable under 35 U.S.C. §103.