PTAB

IPR2025-01582

Curium US LLC v. European Atomic Energy Community Euratom represented BY European Commission

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Treatment of PSMA Expressing Cancers
  • Brief Description: The ’901 patent relates to methods for treating cancers characterized by the overexpression of prostate-specific membrane antigen (PSMA). The claimed methods involve administering a radiopharmaceutical comprising the alpha-emitting radionuclide Actinium-225 (225Ac) chelated to a PSMA-targeting compound within specific dosage ranges.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 4–8, and 10–13 are obvious over Weineisen 2015 in view of Kratochwil.

  • Prior Art Relied Upon: Weineisen 2015 (a 2015 journal article) and Kratochwil (a 2015 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Weineisen 2015 disclosed PSMA I&T, a radiopharmaceutical targeting compound identical to that covered by challenged claims 1 and 2, complexed with a beta-emitter (177Lu). Weineisen 2015 established in human studies that this compound was safe and highly effective for treating metastatic prostate cancer. Kratochwil disclosed a dose escalation study for a structurally similar 225Ac-based radiopharmaceutical (225Ac-DOTATOC), which established well-tolerated and effective unitary doses (18.5 MBq and 25 MBq). Petitioner asserted these doses overlap with or are equivalent to per-body-weight doses within the ranges recited in the challenged claims.
    • Motivation to Combine: A POSITA would combine these teachings to improve upon Weineisen's beta-emitter therapy by substituting the radionuclide with the known superior alpha-emitter, 225Ac. Alpha emitters were understood to offer higher potency and specificity, resulting in greater efficacy with fewer side effects. Weineisen's PSMA I&T was an ideal candidate for this modification because its DOTAGA chelator was considered a "gold standard" for complexing with 225Ac. A POSITA would then look to Kratochwil's human study data to determine a safe and effective dosage, finding direct support for the claimed ranges.
    • Expectation of Success: Petitioner asserted a high expectation of success because swapping radionuclides (e.g., 177Lu for 225Ac) was a well-established practice, and the DOTAGA chelator in PSMA I&T was known to form stable complexes with 225Ac. The known therapeutic advantages of 225Ac, combined with successful human trials of similar compounds at similar doses as shown in Kratochwil, would provide a POSITA with strong confidence that the proposed combination would be safe and effective.

Ground 2: Claim 9 is obvious over Weineisen 2015 in view of Kratochwil and Jurcic.

  • Prior Art Relied Upon: Weineisen 2015 (a 2015 journal article), Kratochwil (a 2015 journal article), and Jurcic (a 2016 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built on Ground 1 to address the narrower dosage range of claim 9, which recites a range of 50 to 200 kBq/kg. Petitioner argued that while Kratochwil taught doses translatable to the higher end of this range (e.g., ~206 kBq/kg), Jurcic provided crucial data supporting the lower end. Jurcic disclosed a Phase I clinical trial for a different 225Ac-based therapy that found doses ranging from 18.5 kBq/kg to 74 kBq/kg to be safe and effective, with the 74 kBq/kg dose identified as promising for further study.
    • Motivation to Combine: A POSITA, having been motivated to create a 225Ac-PSMA I&T therapy as argued in Ground 1, would consult the full range of available clinical data to optimize the dose. The combination of Kratochwil's and Jurcic's findings would direct a POSITA to the specific 50-200 kBq/kg range, as Jurcic's data demonstrated safety and efficacy at the lower end (74 kBq/kg) while Kratochwil supported the higher end. The claimed range in claim 9 directly overlaps with and is strongly supported by Jurcic's clinical findings.

Ground 3: Claims 1, 2, and 4-13 are anticipated by Kratochwil 2016.

  • Prior Art Relied Upon: Kratochwil 2016 (a 2016 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kratochwil 2016 is an enabling prior art publication under 35 U.S.C. §102 that anticipates every limitation of the challenged claims. Petitioner asserted the publication predates the patent's filing date and was authored "by another" because it includes non-inventor co-authors, with no evidence of an exception under §102(b) provided by the Patent Owner. The argument relied heavily on the Patent Owner's own admissions and expert testimony from a prior inter partes review (IPR), IPR2023-00551, where its expert stated that Kratochwil 2016 "embodies all of the challenged claims of the '901 Patent." The reference explicitly discloses treating metastatic castration-resistant prostate cancer (meeting claims 4, 5, and 6) with 225Ac-PSMA-617 (a species of the formulas in claims 1 and 2) at a dose of 100 kBq/kg and a repeat schedule of every 60 days. This disclosed dose and schedule fall squarely within the dosage and timing limitations of all challenged claims (1, 2, 4–8, and 10–13).

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1, 2, and 4-13 of Patent 10,980,901 as unpatentable.