PTAB

IPR2017-01095

Celltrion Inc v. Biogen Inc

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Combination Therapies for B-Cell Lymphomas Comprising Administration of Anti-CD20 Antibodies
  • Brief Description: The ’821 patent relates to methods of treating low-grade or follicular non-Hodgkin's lymphoma (NHL) by administering the anti-CD20 antibody rituximab during a CVP (cyclophosphamide, vincristine, and prednisone) chemotherapy regimen.

3. Key Technical Contentions (Beyond Claim Construction)

  • Petitioner's primary contention was that the ’821 patent is not entitled to its claimed priority date of August 11, 1999. Petitioner argued the great-grandparent application (the '202 application) lacks adequate written description support for the claimed invention, specifically for administering rituximab during CVP chemotherapy to achieve a "beneficial synergistic effect," and for the specific dosing regimen of claims 4-6 ("once every 3 weeks for 8 doses"). Petitioner asserted that because the priority chain is broken, the critical date for prior art purposes is the patent’s actual filing date of June 15, 2012.

4. Grounds for Unpatentability

Ground 1: Anticipation over Marcus - Claims 1-6 are anticipated by Marcus under 35 U.S.C. §102.

  • Prior Art Relied Upon: Marcus (a Feb. 2005 article in Blood).
  • Core Argument for this Ground:
    • Prior Art Mapping: Assuming the patent's effective filing date is June 15, 2012, Marcus qualifies as prior art. Petitioner argued that Marcus, which describes a clinical trial comparing CVP with CVP plus rituximab, explicitly disclosed every element of claims 1-6. This included treating follicular lymphoma by administering 375 mg/m² of rituximab during CVP chemotherapy once every three weeks for eight doses. The reported "major improvement in all clinical endpoints" was alleged to meet the "beneficial synergistic effect" limitation. For claims 3 and 6, which recite specific amino acid sequences, Petitioner contended Marcus inherently disclosed the sequence of the well-known rituximab antibody used in the study.

Ground 2: Obviousness over Czuczman, IDEC, Foon, and Dana - Claims 1-3 are obvious over Czuczman in view of IDEC's 10-K/A, Foon, and Dana.

  • Prior Art Relied Upon: Czuczman (a Nov. 1995 abstract), IDEC's 10-K/A (a Mar. 1998 SEC filing), Foon (a 1995 textbook chapter), and Dana (a 1993 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground applies if the patent is granted its earlier priority date. Czuczman taught that combining rituximab with CHOP chemotherapy for low-grade NHL was safe, effective, and produced synergistic benefits. IDEC's 10-K/A announced plans to test rituximab in combination with other "widely used chemotherapy regimens." Foon and Dana established that CVP was a standard, equally effective, and less toxic alternative to CHOP for treating low-grade NHL.
    • Motivation to Combine: A POSITA, aware of the success of rituximab with CHOP (from Czuczman) and the explicit suggestion to explore other standard regimens (from IDEC), would combine rituximab with CVP. The motivation would be to achieve similar efficacy with a better safety profile, as Foon and Dana taught that CVP was less toxic than CHOP for this patient population.
    • Expectation of Success: Because CVP and CHOP were known to have indistinguishable survival rates for low-grade NHL, a POSITA would have had a reasonable expectation that the success and synergy observed with rituximab-CHOP would translate to a rituximab-CVP combination.

Ground 3: Obviousness over Czuczman et al. plus Link and Piro - Claims 4-6 are obvious over Czuczman, IDEC, Foon, and Dana in view of Link and Piro.

  • Prior Art Relied Upon: The references from Ground 2, plus Link (an Apr. 1998 publication) and Piro (a Nov. 1997 abstract).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground builds upon the core combination of Ground 2 to address the specific dosing regimen of claims 4-6: "once every 3 weeks for 8 doses." Link taught administering rituximab at 375 mg/m² every three weeks for six cycles in combination with CHOP. Piro taught administering rituximab in eight weekly doses as a single agent.
    • Motivation to Combine: A POSITA would be motivated to optimize the known parameters of rituximab-chemotherapy combinations. It would have been a matter of routine optimization to combine Link's three-week dosing interval with the known concept of an eight-dose course of treatment from Piro to determine the optimal duration and frequency for improving patient outcomes.
    • Expectation of Success: The prior art established the safety and efficacy of the components (rituximab, CVP, a 3-week cycle, and an 8-dose course). A POSITA would have reasonably expected that combining these known elements would yield a predictable and effective treatment regimen.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims 3 and 6 were obvious over Marcus in view of the ’137 patent (which explicitly discloses rituximab's amino acid sequence) and that claims 3 and 6 were obvious over the combination of Czuczman, IDEC, Foon, Dana, Link, Piro, and the ’137 patent.

5. Key Claim Construction Positions

  • Petitioner argued the term "beneficial synergistic effect" should be construed to mean "an improvement in clinical outcome." This construction was based on the Patent Owner's arguments during prosecution, where it pointed to data from the Marcus study showing improved progression-free survival as evidence of such an effect.

6. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 1-6 of the ’821 patent as unpatentable.