PTAB

IPR2025-00799

Intas Pharmaceuticals Ltd v. Atossa Therapeutics Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Methods for making and using Endoxifen
  • Brief Description: The ’151 patent relates to compositions comprising a specific crystalline form of (Z)-endoxifen, designated “Form I,” which is characterized by a specific X-ray powder diffraction (XRPD) profile. The patent also covers methods of using these compositions to treat hormone-dependent breast disorders.

3. Grounds for Unpatentability

Ground 1: Claims 1-6, 16, 18, and 21 are anticipated by Liu

  • Prior Art Relied Upon: Liu (WO 2017/070651).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Liu disclosed every element of the challenged claims. Liu explicitly taught methods for synthesizing and purifying endoxifen to achieve a crystalline composition with greater than 90% (Z)-isomer purity for treating hormone-dependent breast disorders. While Liu did not provide XRPD data or identify the resulting crystal as "Form I," Petitioner contended that Form I is an inherent, unstated property of the material produced by Liu's disclosed methods. To support this, Petitioner's expert allegedly reproduced two of Liu’s synthesis and purification procedures (sequential recrystallization and isomerization followed by recrystallization) and subjected the resulting highly pure (Z)-endoxifen samples to XRPD analysis. The analysis reportedly confirmed that both methods produced crystalline material with XRPD patterns matching the peaks claimed for Form I. Therefore, Petitioner asserted Liu inherently disclosed the claimed composition and methods of use.

Ground 2: Claims 1-21 are obvious over Liu and Ahmad

  • Prior Art Relied Upon: Liu (WO 2017/070651) and Ahmad (Patent 9,333,190), in view of the general knowledge of a person of ordinary skill in the art (POSA) as evidenced by secondary references.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Liu taught the base composition: a highly pure, crystalline form of (Z)-endoxifen that inherently possesses the claimed Form I structure. Ahmad taught formulating (Z)-endoxifen (of at least 90% purity) for treating breast cancer. Ahmad’s teachings included formulating the active ingredient with pharmaceutically acceptable carriers and diluents into oral dosage forms like tablets and capsules, including enteric-coated and delayed-release versions. For method claims, Liu and Ahmad both disclosed using (Z)-endoxifen to treat hormone-dependent breast disorders. Petitioner argued that the pharmacokinetic parameters recited in dependent claims (e.g., half-life, steady-state plasma levels, AUC) were either inherent properties of administering the obvious formulation or would have been obvious to achieve through routine optimization, as supported by clinical data in other prior art.
    • Motivation to Combine: A POSA, knowing from Liu how to create a highly pure (Z)-endoxifen active pharmaceutical ingredient (API), would combine this API with the well-established formulation and delivery technologies for that same API as taught by Ahmad. The motivation would be the straightforward and well-understood goal of developing a stable and effective oral drug product for the known therapeutic purpose of treating breast cancer, thereby improving upon existing treatments like tamoxifen.
    • Expectation of Success: A POSA would have had a high expectation of success. The combination involved applying conventional formulation techniques (carriers, oral dosage forms, enteric coatings) to a known API to achieve its known therapeutic effect. The result was predictable and amounted to the sum of its known parts, requiring only routine implementation rather than inventive skill.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued against discretionary denial under 35 U.S.C. §325(d), asserting that the Examiner committed a material error during prosecution. While the Liu and Ahmad references were cited to the Examiner, the core of Petitioner’s invalidity argument was not considered. Specifically, the Examiner did not have the benefit of the new experimental XRPD data generated by Petitioner, which allegedly proves that Liu’s disclosed method inherently produces the claimed Form I polymorph. Petitioner contended that this new evidence and the resulting inherency argument were never before the Office and are necessary to correct the Examiner’s erroneous allowance of the claims, which was based on the novelty of the Form I polymorph without considering whether prior art methods created it.

5. Relief Requested

  • Petitioner requests that the Board institute an inter partes review and cancel claims 1-21 of Patent 11,261,151 as unpatentable under 35 U.S.C. §102 and §103.