PTAB

IPR2016-01317

Argentum Pharmaceuticals LLC v. Janssen Oncology Inc

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1. Case Identification

2. Patent Overview

  • Title: Methods and Compositions for Treating Cancer
  • Brief Description: The ’438 patent discloses a method for treating prostate cancer in a human by administering a therapeutically effective amount of abiraterone acetate (or a salt thereof) in combination with a therapeutically effective amount of prednisone.

3. Grounds for Unpatentability

Ground 1: Obviousness over O'Donnell and Gerber - Claims 1-20 are obvious over O'Donnell in view of Gerber.

  • Prior Art Relied Upon: O'Donnell (a 2004 journal article on abiraterone acetate) and Gerber (a 1990 journal article on ketoconazole and prednisone).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that O'Donnell taught all elements of claim 1 except for the specific co-administration of prednisone. O'Donnell disclosed using abiraterone acetate, a CYP17 inhibitor, to treat prostate cancer by suppressing testosterone. Critically, O'Donnell recognized that this treatment could cause adrenocortical suppression (reduced cortisol) and suggested that concomitant administration of a replacement glucocorticoid might be necessary, noting it was common practice with ketoconazole. Gerber provided the missing element by teaching the safe and effective combination of ketoconazole (another CYP17 inhibitor) with prednisone (a glucocorticoid) for treating patients with hormone-refractory metastatic prostate cancer.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would combine these references to create a safer and more effective treatment. O'Donnell identified the known problem of cortisol suppression with CYP17 inhibitors and suggested a solution (glucocorticoid replacement). Gerber provided a specific, successful example of this solution in practice with a similar drug. A POSITA would have been motivated to substitute the more selective and effective CYP17 inhibitor from O'Donnell (abiraterone acetate) for ketoconazole in the established combination therapy taught by Gerber to manage the well-known side effects.
    • Expectation of Success: A POSITA would have had a high expectation of success. Gerber demonstrated that combining a CYP17 inhibitor with prednisone was safe and effective. The purpose of adding prednisone—to act as a glucocorticoid replacement and mitigate predictable side effects—was well understood. Therefore, applying this known safety-enhancing agent to a more potent primary drug like abiraterone acetate would have been a predictable and successful modification.

Ground 2: Obviousness over the ’213 Patent and Gerber - Claims 1-20 are obvious over the ’213 patent in view of Gerber.

  • Prior Art Relied Upon: Patent 5,604,213 (’213 patent) and Gerber (a 1990 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented an alternative primary reference for the abiraterone acetate element. Petitioner asserted that the ’213 patent explicitly disclosed abiraterone acetate and its use in treating prostate cancer. The ’213 patent also taught that abiraterone acetate was a superior CYP17 inhibitor compared to ketoconazole. As in Ground 1, Gerber taught the safe and effective practice of co-administering prednisone with ketoconazole to treat prostate cancer and manage side effects.
    • Motivation to Combine: The motivation was substantially the same as in Ground 1. The ’213 patent established abiraterone acetate as a known and superior agent for treating prostate cancer. A POSITA, aware of the known class-wide side effects of CYP17 inhibitors, would have looked to established clinical practice for managing them. Gerber provided this established practice: co-administering prednisone. Therefore, a POSITA would combine the superior drug from the ’213 patent with the known supportive care agent from Gerber.
    • Expectation of Success: The expectation of success was high and based on the same reasoning as Ground 1. The combination involved applying a known solution (prednisone for side effect management) to a known problem inherent in a class of drugs (CYP17 inhibitors), with the ’213 patent simply providing a better primary drug within that class.

4. Key Claim Construction Positions

  • Petitioner noted that the Board adopted several claim constructions in the related IPR2016-00286 proceeding and that it would not separately address them. The key adopted constructions relevant to the petition include:
    • "treat," "treating," and "treatment": "include the eradication, removal, modification, management or control of a tumor or primary, regional, or metastatic cancer cells or tissue and the minimization or delay of the spread of cancer"
    • "refractory cancer": "cancer that is not responding to an anti-cancer treatment or cancer that is not responding sufficiently to an anti-cancer treatment"
    • "therapeutically effective amount of prednisone": "an amount of prednisone effective for treating prostate cancer"

5. Key Technical Contentions (Beyond Claim Construction)

  • Rebuttal of Secondary Considerations of Non-Obviousness: Petitioner dedicated significant argument to preemptively rebutting the Patent Owner's likely reliance on secondary considerations, particularly the commercial success of the drug Zytiga® (abiraterone acetate).
    • Lack of Nexus: Petitioner argued that the commercial success of Zytiga® could not be attributed to the claimed invention (the combination of abiraterone acetate and prednisone). Instead, any success was due to the efficacy of the active ingredient, abiraterone acetate, alone. Petitioner contended that prednisone was not added to enhance the anti-cancer effect but merely to manage the expected side effects of CYP17 inhibition, a standard practice. Thus, no nexus existed between the claimed combination and the product's commercial success.
    • Blocking Patent: Petitioner asserted that the ’213 patent, which claims abiraterone acetate itself and its use in treating prostate cancer, acted as a blocking patent. This prevented others from marketing abiraterone acetate, thereby weakening any inference of non-obviousness from Zytiga's® commercial success, as there was no open market for others to develop similar obvious combinations.

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-20 of the ’438 patent as unpatentable.