PTAB

IPR2016-00286

Amerigen Pharmaceuticals Ltd v. Janssen Oncology Inc

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Key Events
Petition

1. Case Identification

2. Patent Overview

  • Title: Methods and Compositions for Treating Cancer
  • Brief Description: The ’438 patent discloses methods for treating prostate cancer by co-administering a therapeutically effective amount of abiraterone acetate (a CYP17 inhibitor) with a therapeutically effective amount of prednisone (a glucocorticoid).

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 article in the British Journal of Cancer) and Gerber (a 1990 article in The Journal of Urology).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that O'Donnell taught treating prostate cancer with abiraterone acetate, a CYP17 inhibitor that suppresses testosterone production. O'Donnell recognized that this treatment could cause adrenocortical suppression (a decrease in cortisol) and explicitly suggested that replacement glucocorticoid therapy may be necessary, noting it was common practice when using a similar drug, ketoconazole. Gerber taught that the combination of ketoconazole (another CYP17 inhibitor) and prednisone (a glucocorticoid) was a safe and effective treatment for patients with hormone-refractory metastatic prostate cancer. Petitioner asserted that claim 1's method of co-administering abiraterone acetate and prednisone was therefore disclosed by the combined teachings of the prior art. Dependent claims reciting specific dosages and patient populations were argued to be disclosed or rendered obvious by specific teachings within O'Donnell (e.g., patient types, abiraterone dosage ranges) and Gerber (e.g., prednisone dosage).
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would have been motivated to replace ketoconazole in the established Gerber combination with the more selective and potent abiraterone acetate taught by O'Donnell. The motivation was not to create a synergistic anti-cancer effect, but to use a superior primary drug (abiraterone acetate) while continuing the known, necessary supportive care (prednisone) to manage the predictable side effects of CYP17 inhibition, as explicitly suggested by O'Donnell.
    • Expectation of Success: A POSITA would have had a high expectation of success. Since combining ketoconazole with prednisone was known to be safe and effective, substituting it with a more potent drug from the same class was a predictable improvement. The success sought was effective cancer treatment with managed side effects, a result the prior art made highly probable.
    • Key Aspects: Petitioner argued that the Patent Owner overcame prosecution history rejections by mischaracterizing the commercial success of its drug Zytiga® as an unexpected result of the combination. Petitioner contended the success was attributable to abiraterone acetate alone (taught in the prior art) and that the addition of prednisone was merely an expected measure to improve safety and tolerability, not efficacy.

Ground 2: Obviousness over the '213 patent and Gerber - Claims 1-4 and 6-11 are obvious over the '213 patent in view of Gerber.

  • Prior Art Relied Upon: Patent 5,604,213 (’213 patent) and Gerber (a 1990 article in The Journal of Urology).
  • Core Argument for this Ground:
    • Prior Art Mapping: The ’213 patent, which is not related to the ’438 patent, disclosed abiraterone acetate and its use in treating androgen-dependent disorders like prostate cancer. The ’213 patent established abiraterone acetate as a potent CYP17 inhibitor and reported that it was significantly more effective than ketoconazole at inhibiting testosterone synthesis. As in Ground 1, Gerber taught the safe and effective use of ketoconazole in combination with prednisone. The core elements of the claimed invention—abiraterone acetate for prostate cancer and its combination with prednisone—were therefore present in the prior art.
    • Motivation to Combine: The motivation was identical to that in Ground 1: to improve upon the existing ketoconazole/prednisone therapy. A POSITA, knowing from the ’213 patent that abiraterone acetate was a superior alternative to ketoconazole, would have been motivated to substitute it into the known combination therapy from Gerber. This would be a straightforward and logical step to enhance the primary therapeutic effect while using a standard method to mitigate known side effects of the drug class.
    • Expectation of Success: A POSITA would have reasonably expected the combination to be successful. The ’213 patent provided clear data on the potency of abiraterone acetate, and Gerber established the utility of prednisone as a co-therapy for this class of drug. Combining the two was a predictable optimization of an existing treatment paradigm.

4. Key Claim Construction Positions

  • "treat," "treating," and "treatment": Petitioner proposed these terms be construed as defined in the ’438 patent’s specification: "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."
  • "anti-cancer agent": Petitioner proposed this term be construed as defined in the specification: "any therapeutic agent that directly or indirectly kills cancer cells or directly or indirectly prohibits, stops or reduces the proliferation of cancer cells."
  • "refractory cancer": Petitioner proposed this term be construed as defined in the specification: "cancer that is not responding to an anti-cancer treatment or cancer that is not responding sufficiently to an anti-cancer treatment."

5. Key Technical Contentions (Beyond Claim Construction)

  • Role of Prednisone: A central contention was that prednisone's role in the claimed combination is not as an anti-cancer agent but as hormone replacement therapy. Petitioner argued that CYP17 inhibitors like abiraterone acetate are known to cause side effects (e.g., hypertension, hypokalemia) by suppressing cortisol production. Administering a glucocorticoid like prednisone was a known and expected method to counteract these side effects, rather than to provide a synergistic anti-cancer benefit. This argument directly challenged the patentability of the combination, framing it as the pairing of a known drug with its known supportive care regimen.

6. Relief Requested

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