PTAB

IPR2017-01959

Samsung Bioepis Co Ltd v. Genentech Inc

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Dosages for treatment with Anti-ErbB2 Antibodies
  • Brief Description: The ’379 patent discloses methods of treating cancers characterized by ErbB2 receptor overexpression. The methods involve administering an anti-ErbB2 antibody using a "front-loaded" dosing regimen with an initial dose followed by subsequent doses at intervals of at least two weeks.

3. Grounds for Unpatentability

Ground 1: Claims 1-3, 5, 7, 9-11, 16-28, and 30-40 are obvious over the Herceptin Label in view of Baselga ’96, Pegram ’98, and the knowledge of a POSA.

  • Prior Art Relied Upon: Herceptin Label (1998 FDA Approved Label for rhuMAb HER2), Baselga ’96 (a 1996 journal article detailing a Phase II study of rhuMAb HER2), and Pegram ’98 (a 1998 journal article detailing a Phase II study of rhuMAb HER2 plus cisplatin).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the combination of prior art taught all limitations of the challenged claims. The Herceptin Label, the FDA-approved package insert for the commercial embodiment of the claimed antibody (trastuzumab), disclosed treating ErbB2-overexpressing metastatic breast cancer with a front-loaded, weekly dosing regimen of the antibody. Crucially, it taught that doses up to 500 mg had been safely administered and that the antibody had an average half-life of approximately 12 days at that dose. Petitioner asserted that for a standard patient weight range (55-85 kg), the disclosed 500 mg absolute dose converts to a weight-based dose of at least 5 mg/kg, meeting the initial dose limitation of independent claim 1. The Herceptin Label also explicitly taught combination therapy with chemotherapeutic agents like paclitaxel, which were administered on a tri-weekly (every 21 days) schedule. The Baselga ’96 and Pegram ’98 clinical trial publications established a known target minimum trough serum concentration of 10-20 µg/mL for therapeutic efficacy.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSA) would combine these references to optimize the existing, approved therapy. The primary motivation was to improve patient convenience, compliance, and quality of life by reducing the frequency of antibody injections to match the tri-weekly schedule of co-administered chemotherapy (paclitaxel). Aligning the dosing schedules would reduce the number of required hospital visits for terminally ill patients, a well-understood goal in clinical oncology. This alignment would reduce patient burden, travel time, and costs, while improving clinical efficiency.
    • Expectation of Success: A POSA would have had a strong expectation of success in developing a less frequent, multi-week dosing regimen. The Herceptin Label's disclosure of a long half-life (12 days) inherently suggested that weekly dosing was not required to maintain therapeutic concentrations. Petitioner argued that a POSA, armed with the pharmacokinetic data from the Herceptin Label (half-life, volume of distribution), the target trough concentration from Baselga ’96 and Pegram ’98, and standard, textbook pharmacokinetic equations (based on a one-compartment model taught by Baselga ’96), could routinely calculate and predict that a tri-weekly regimen would maintain serum levels well above the required therapeutic threshold. The known safety profile of the antibody at high doses (500 mg) further assured a POSA that such a regimen would be safe and effective. The development of such a schedule was presented not as an inventive leap, but as a routine optimization based on publicly available data and predictable principles.

4. Key Claim Construction Positions

  • Petitioner submitted that the term "ErbB2 receptor" in the ’379 patent claims should be understood to be interchangeable with "HER2," "ErbB2," or "p185HER2," consistent with the patent’s specification.
  • Beyond this clarification, Petitioner stated it assumed the challenged claims possess their broadest reasonable construction.

5. Key Technical Contentions (Beyond Claim Construction)

  • A central technical contention was that modifying a drug's dosing frequency based on its known pharmacokinetic properties was a routine optimization for a POSA at the time.
  • Petitioner's core technical argument relied on the assertion that a POSA could use standard, textbook pharmacokinetic equations for a one-compartment model to reliably predict the serum concentration of the antibody over time. By inputting the half-life and volume of distribution from the Herceptin Label, a POSA could calculate that a tri-weekly dosing schedule would successfully maintain concentrations above the known therapeutic trough level disclosed in Baselga ’96 and Pegram ’98.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and cancellation of claims 1-3, 5, 7, 9-11, 16-28, and 30-40 of Patent 7,371,379 as unpatentable under 35 U.S.C. §103.