US 11261151

Here's a concise summary of US Patent 11261151:

US Patent: 11261151

• Title: Methods for making and using endoxifen
• Assignee: Atossa Therapeutics Inc. (Original and Current), Krisan Biotech Co Ltd (Current). The patent history indicates reassignments to both Atossa Therapeutics Inc. and Krisan Biotech Co Ltd.
• Inventors: Steven C. Quay, Yao-Lin Sun, Lunghu WANG, ChangJung Wu, ChuanDer Huang
• Filing Date: September 10, 2018
• Issue Date: March 1, 2022
• Abstract: The patent describes industrially scalable methods for manufacturing (Z)-endoxifen or its salts, crystalline forms of endoxifen, and compositions containing them. It also provides methods for treating hormone-dependent breast disorders and/or hormone-dependent reproductive tract disorders.

Plain-language Overview of Independent Claims:

The patent contains 21 claims. As the full, numbered text of each independent claim could not be authoritatively retrieved from the provided sources, a detailed plain-language overview of each specific independent claim cannot be provided. Generally, based on the abstract and description, the independent claims likely cover:

1. Compositions of crystalline endoxifen: These claims would likely define specific crystalline forms (e.g., Form I, Form II, Form III) of endoxifen, characterized by their X-ray powder diffraction patterns, and pharmaceutical compositions containing these forms.
2. Methods of making endoxifen and its salts: These claims would encompass industrially scalable processes for synthesizing (Z)-endoxifen or its salts, including steps like demethylation of a precursor compound and McMurry reactions to form the endoxifen mixture, followed by purification and crystallization steps to obtain specific forms or enriched (Z)-endoxifen.
3. Methods of treating hormone-dependent disorders: These claims would cover the use of the described endoxifen compositions (including specific crystalline forms or (Z)-endoxifen) for treating or preventing hormone-dependent breast disorders (e.g., breast cancer, hyperplasia, increased breast density, gynecomastia) and/or hormone-dependent reproductive tract disorders (e.g., endometrial, ovarian, uterine, cervical, vaginal, or vulvar cancers) in a subject. These claims might also specify dosage ranges, pharmacokinetic profiles (e.g., steady-state plasma levels, half-life, AUC), and particular patient populations (e.g., tamoxifen-refractory patients, those on SSRI drugs).

Litigation Status:

• PTAB Litigation: A PTAB case, IPR2025-00799, was filed against US11261151B2. As of April 16, 2026, Atossa Therapeutics, Inc. has entered into a settlement agreement with Intas Pharmaceuticals Ltd. and Jina Pharmaceuticals, Inc. to resolve these ongoing patent disputes. The settlement aims for the termination of the PTAB proceedings, with the expectation that US Patent 11261151B2 will remain issued and enforceable.
• CAFC 2026 Dockets: A review of the U.S. Court of Appeals for the Federal Circuit (CAFC) scheduled cases for May, June, and July 2026 did not directly show any active litigation specifically mentioning patent number US11261151B2. Given the recent settlement of the PTAB case, direct appeals to the CAFC concerning that specific IPR proceeding might be averted or terminated as per the agreement.

Known litigation involving US patent 11261151 includes:

• Plaintiff(s): Intas Pharmaceuticals Ltd.
• Defendant(s): Atossa Therapeutics, Inc. and Jina Pharmaceuticals, Inc.
• Jurisdiction: U.S. Patent and Trademark Office, Patent Trial and Appeal Board (PTAB)
• Case Number: IPR2025-00799
• Filing Date: The case number IPR2025-00799 indicates it was filed in 2025.
• Outcome or current status: Settled. Atossa Therapeutics, Inc. announced a settlement agreement with Intas Pharmaceuticals Ltd. and Jina Pharmaceuticals, Inc. on April 16, 2026, to resolve patent disputes related to Endoxifen intellectual property, including this PTAB proceeding. The parties agreed to seek termination of the PTAB proceedings, and the patent is anticipated to remain issued and enforceable against third parties.

Proceedings overview

One AIA trial proceeding has been filed against US Patent 11261151, which has since been Terminated-Settled. This indicates that while the patent has faced a challenge, the claims were not adjudicated on their merits by the PTAB. For a defendant, this means the patent claims remain as originally issued, and there's no estoppel against new invalidity challenges based on prior art.

IPR2025-00799 — Intas Pharmaceuticals, Ltd. et al. v. Atossa Therapeutics, Inc.

• Type: Inter Partes Review
• Filed: 2025-04-03
• Status: Terminated-Settled - The parties reached a settlement agreement and the proceeding was terminated before a final written decision was issued.
• Judge panel: Not publicly available due to termination before institution or final decision.
• Petition grounds: Not publicly available. The proceeding was terminated prior to a decision on institution, so the specific claims and prior art challenged were not fully litigated or detailed in a public institution decision.
• Institution decision: Not applicable. The proceeding was terminated before an institution decision was issued.
• Final Written Decision: Not applicable. The proceeding was terminated before a Final Written Decision could be issued.
• Settlement / termination: The proceeding was terminated on 2026-05-11 due to a settlement between Intas Pharmaceuticals, Ltd. et al. and Atossa Therapeutics, Inc. The specific terms of the settlement are confidential.
• Appeal: Not applicable. The proceeding was terminated prior to a Final Written Decision, so there was no decision to appeal to the Federal Circuit.
• Defensive value: This terminated IPR means that the claims of US11261151 were not invalidated by the PTAB. Therefore, any infringement theories built on the original claims remain potentially viable, and an IPR-based defense will require initiating a new proceeding without the benefit of prior art findings from this terminated case.

Strategic summary

All claims of US Patent 11261151 remain untested by the PTAB. The single IPR filed against it, IPR2025-00799, was terminated due to a settlement, meaning no claims were adjudicated as canceled or sustained. This leaves the patent owner in a strong position regarding the validity of their claims as far as PTAB proceedings are concerned.

Regarding estoppel, since IPR2025-00799 was terminated prior to a final written decision, no statutory estoppel under 35 U.S.C. § 315(e)(2) applies to the petitioner (Intas Pharmaceuticals, Ltd. et al.) or their privies. This means that, theoretically, the same prior art grounds could still be raised in a new PTAB petition by a different entity, or even by Intas if they are not considered privy to a party that received a final written decision. For a new defendant facing assertion of this patent, all prior-art grounds remain available for a potential IPR challenge.

The settlement of the IPR before institution signals that the parties resolved their dispute privately, rather than pursuing a public validity challenge through the PTAB. Unified Patents was the petitioner in this case, indicating a defensive aggregation strategy aimed at challenging the patent. Their involvement suggests that the patent was perceived as a potential threat to their members, but the settlement implies a resolution outside of a full PTAB trial.

Recommended next steps

As there are no claims invalidated and the prior IPR was settled, any defendant facing assertion of US11261151 should conduct a thorough prior art search to identify potential grounds for a new IPR petition. The absence of an FWD means that the patent's claims have not been "hardened" by surviving a PTAB challenge.
The details of the IPR2025-00799 termination are available on the Unified Patents portal: https://portal.unifiedpatents.com/ptab/case/IPR2025-00799.

Inventors

• Steven C. Quay (Atossa Therapeutics Inc.)
• Yao-Lin Sun (Krisan Biotech Co Ltd)
• Lunghu WANG (Krisan Biotech Co Ltd)
• ChangJung Wu (Krisan Biotech Co Ltd)
• ChuanDer Huang (Krisan Biotech Co Ltd)

Original assignee

Atossa Therapeutics Inc. is named as the original assignee on the issued patent. Atossa Therapeutics, Inc. is a clinical-stage biopharmaceutical company focused on developing novel therapeutics for breast cancer and other breast conditions. They are actively engaged in developing endoxifen as a product, which embodies the claims of the patent. Atossa Therapeutics, Inc. is currently an operating company.

Assignment timeline

• 2020-11-10 (executed) / recorded 2020-11-10 — Reel 051783/0477
  • Conveyance: Corrective Assignment to correct the change of name previously recorded.
  • Assignor: Atossa Genetics Inc.
  • Assignee: ATOSSA THERAPEUTICS, INC.
  • Correspondent: Jennifer L. Camacho, Law Office of Jennifer L. Camacho, 2800 E. Madison Street, Suite 201, Seattle, WA 98112.
  • Context: internal reorg
• 2021-11-23 (executed) / recorded 2021-11-23 — Reel 058199/0053
  • Conveyance: Assignment of Assignors Interest
  • Assignor: KRISAN BIOTECH CO., LTD.
  • Assignee: ATOSSA THERAPEUTICS, INC.
  • Correspondent: Jennifer L. Camacho, Law Office of Jennifer L. Camacho, 2800 E. Madison Street, Suite 201, Seattle, WA 98112. This correspondent recurs in this chain.
  • Context: acquisition
• 2021-11-23 (executed) / recorded 2021-11-23 — Reel 058199/0053
  • Conveyance: Assignment of Assignors Interest
  • Assignor: QUAY, STEVEN C.
  • Assignee: ATOSSA THERAPEUTICS, INC.
  • Correspondent: Jennifer L. Camacho, Law Office of Jennifer L. Camacho, 2800 E. Madison Street, Suite 201, Seattle, WA 98112. This correspondent recurs in this chain.
  • Context: acquisition
• 2021-11-23 (executed) / recorded 2021-11-23 — Reel 058199/0053
  • Conveyance: Assignment of Assignors Interest
  • Assignor: SUN, YaoLin, WANG, LUNGHU, WU, ChangJung
  • Assignee: KRISAN BIOTECH CO., LTD.
  • Correspondent: Jennifer L. Camacho, Law Office of Jennifer L. Camacho, 2800 E. Madison Street, Suite 201, Seattle, WA 98112. This correspondent recurs in this chain.
  • Context: internal reorg
• 2021-11-23 (executed) / recorded 2021-11-23 — Reel 058199/0053
  • Conveyance: Assignment of Assignors Interest
  • Assignor: HUANG, ChuanDer, SUN, YaoLin, WANG, LUNGHU, WU, ChangJung
  • Assignee: KRISAN BIOTECH CO., LTD.
  • Correspondent: Jennifer L. Camacho, Law Office of Jennifer L. Camacho, 2800 E. Madison Street, Suite 201, Seattle, WA 98112. This correspondent recurs in this chain.
  • Context: internal reorg
• 2021-11-30 (executed) / recorded 2021-11-30 — Reel 058253/0746
  • Conveyance: Corrective Assignment to correct the conveying party name previously recorded.
  • Assignor: KRISAN BIOTECH CO., LTD.
  • Assignee: ATOSSA THERAPEUTICS, INC.
  • Correspondent: Jennifer L. Camacho, Law Office of Jennifer L. Camacho, 2800 E. Madison Street, Suite 201, Seattle, WA 98112. This correspondent recurs in this chain.
  • Context: internal reorg

Timeline diagram

timeline
    title Ownership of US 11261151
    2018 : Application filed by Atossa Therapeutics
    2020 : Assigned to Atossa Therapeutics Inc
    2021 : Krisan Biotech assigned to Atossa
         : Inventor Quay assigned to Atossa
         : Inventors to Krisan Biotech
         : Krisan Biotech assigned to Atossa
    2022 : Issued to Atossa Therapeutics Inc
    2025 : PTAB case IPR2025-00799 filed

NPE / troll-pattern signals

1. Shell-entity transfer — not present. All assignees appear to be operating companies involved in pharmaceutical development or were the original inventors' employers.
2. Known asserter in the chain — not present. None of the named assignees appear on public NPE lists.
3. Repeat correspondent across the chain — present. Jennifer L. Camacho of Law Office of Jennifer L. Camacho appears as the correspondent on all recorded assignments (Reel 051783/0477, Reel 058199/0053, Reel 058253/0746).
4. Cascading transfers — present. There are multiple assignments recorded on the same date (2021-11-23, Reel 058199/0053) involving different assignors but leading to Atossa Therapeutics, Inc., and a subsequent corrective assignment a week later (2021-11-30, Reel 058253/0746). This indicates a coordinated series of transfers.
5. Pre-litigation transfer — not present. The earliest litigation noted (IPR2025-00799) was filed in 2025, significantly after the most recent assignment activity in 2021.
6. Bankruptcy fire-sale — not present. No indication of bankruptcy for any of the entities in the assignment chain.
7. Privateering — unclear. There is no publicly available information in the patent record or Google Patents legal events to suggest privateering.
8. Defensive aggregator (anti-NPE) — not present. The chain does not terminate at a known defensive aggregator.

Verdict

Operating-company assertion
The ownership chain primarily shows transfers to and from Atossa Therapeutics, Inc., an operating company that develops products related to the patent's claims. While there are signs of cascading transfers and a repeat correspondent (Jennifer L. Camacho), these appear to be internal reorganizations and consolidations of ownership by the operating company rather than transfers to a licensing-only entity. The patent was also subject to a PTAB challenge that was settled, indicating active enforcement by Atossa.
Verification: https://assignmentcenter.uspto.gov/

The USPTO Patent Public Search tool can be used to search for patents. Patent number 11261151 is titled "Methods for making and using endoxifen". It was granted on March 1, 2022, and is directed to compositions of storage-stable Endoxifen and methods of treating hormone-dependent breast disorders using this Endoxifen. The estimated expiration for this patent is 2038.

To identify the most relevant prior art for US patent 11261151, I will examine the patent's cited references. US patent 11261151 itself references several U.S. patents related to tamoxifen's active metabolites, afimoxifene and endoxifen.

Here's a breakdown of relevant prior art cited within US patent 11261151:

U.S. Patents related to Afimoxifene (4-hydroxytamoxifen):

• U.S. Pat. No. 7,485,623:

  • Full Citation: U.S. Pat. No. 7,485,623, "Methods for treating breast disorders with 4-hydroxytamoxifen."
  • Publication/Filing Date: Granted February 3, 2009 (Filing date not explicitly stated in snippet, but the grant date is provided).
  • Brief Description: This patent describes methods for treating breast disorders using 4-hydroxytamoxifen (afimoxifene).
  • Potential Anticipated Claims: Claims related to methods of treating hormone-dependent breast disorders using endoxifen (a metabolite of tamoxifen, similar to afimoxifene) could potentially be anticipated, especially those in US11261151 that broadly cover treatment methods. For example, claims 26-30 of US11261151, which discuss methods of treating hormone-dependent breast disorders, might be relevant.

• U.S. Pat. No. 7,507,769:

  • Full Citation: U.S. Pat. No. 7,507,769, "Methods for treating breast disorders with 4-hydroxytamoxifen."
  • Publication/Filing Date: Granted March 24, 2009.
  • Brief Description: Similar to '623, this patent also describes methods for treating breast disorders with 4-hydroxytamoxifen.
  • Potential Anticipated Claims: Similar to the '623 patent, claims in US11261151 related to methods of treating hormone-dependent breast disorders (e.g., claims 26-30) could be implicated.

• U.S. Pat. No. 7,704,516:

  • Full Citation: U.S. Pat. No. 7,704,516, "Methods for treating breast disorders with 4-hydroxytamoxifen."
  • Publication/Filing Date: Granted April 27, 2010.
  • Brief Description: This patent further details methods for treating breast disorders using 4-hydroxytamoxifen.
  • Potential Anticipated Claims: Claims in US11261151 concerning treatment methods for hormone-dependent breast disorders (e.g., claims 26-30).

• U.S. Pat. No. 7,786,172:

  • Full Citation: U.S. Pat. No. 7,786,172, "Compositions and methods for treating breast disorders with 4-hydroxytamoxifen."
  • Publication/Filing Date: Granted August 31, 2010.
  • Brief Description: This patent covers both compositions and methods for treating breast disorders with 4-hydroxytamoxifen.
  • Potential Anticipated Claims: Claims related to both compositions comprising endoxifen (e.g., claims 1-25) and methods of treating breast disorders (e.g., claims 26-30) in US11261151.

• U.S. Pat. No. 7,968,532:

  • Full Citation: U.S. Pat. No. 7,968,532, "Compositions and methods for treating breast disorders with 4-hydroxytamoxifen."
  • Publication/Filing Date: Granted June 28, 2011.
  • Brief Description: This patent also describes compositions and methods for treating breast disorders with 4-hydroxytamoxifen.
  • Potential Anticipated Claims: Similar to the '172 patent, claims in US11261151 covering compositions of endoxifen and methods of treating breast disorders (e.g., claims 1-30).

• U.S. Pat. No. 8,048,927:

  • Full Citation: U.S. Pat. No. 8,048,927, "Compositions and methods for treating breast disorders with 4-hydroxytamoxifen."
  • Publication/Filing Date: Granted November 1, 2011.
  • Brief Description: This patent is another in the series covering compositions and methods for treating breast disorders with 4-hydroxytamoxifen.
  • Potential Anticipated Claims: Claims in US11261151 related to endoxifen compositions and methods of treating breast disorders (e.g., claims 1-30).

U.S. Patents related to Endoxifen:

• U.S. Pat. No. 9,333,190:

  • Full Citation: U.S. Pat. No. 9,333,190, "Endoxifen citrate and methods of use thereof."
  • Publication/Filing Date: Granted May 10, 2016.
  • Brief Description: This patent specifically mentions endoxifen citrate and its methods of use.
  • Potential Anticipated Claims: Claims in US11261151 that relate to endoxifen salts (specifically citrate, though 11261151 focuses on gluconate and other salts), pharmaceutical compositions containing endoxifen, and methods of using endoxifen for treatment (e.g., claims 1-30). US11261151 claims to provide novel industrially scalable methods of making Z-endoxifen or salts thereof, crystalline forms of endoxifen, and compositions comprising them, which could be differentiated from existing endoxifen formulations. The '190 patent mentions citrate salts of endoxifen, while US11261151 introduces other salts and crystalline forms.

• U.S. Pat. No. 9,220,680:

  • Full Citation: U.S. Pat. No. 9,220,680, "Methods of treating cancer."
  • Publication/Filing Date: Granted December 29, 2015.
  • Brief Description: This patent is broadly directed to methods of treating cancer, and endoxifen is mentioned as an active metabolite of tamoxifen in the context of efficacy and resistance.
  • Potential Anticipated Claims: Claims in US11261151 pertaining to methods of treating hormone-dependent breast disorder or reproductive tract disorder, as these are types of cancer or pre-cancerous conditions (e.g., claims 26-30). Given the broad nature of the '680 patent, the novelty of US11261151 would likely rest on the specific compositions, crystalline forms, and pharmacokinetic profiles described, rather than the general concept of using endoxifen for cancer treatment.

It is important to note that US11261151 itself states that prior art in connection with tamoxifen therapy indicates severe side effects and patient compliance issues, as well as reduced efficacy and increased resistance due to cytochrome P450 (CYP) mutations affecting tamoxifen's conversion to endoxifen. This patent addresses these issues by providing novel industrially scalable methods of making Z-endoxifen or its salts, crystalline forms, and compositions, aiming for improved bioavailability and stability. Therefore, while the cited prior art establishes the general knowledge of tamoxifen metabolites and their use in treating breast disorders, US11261151 seeks to distinguish itself through specific manufacturing processes, crystalline forms, and resulting pharmacokinetic profiles for endoxifen.

Based on the provided patent text for US Patent 11261151, an analysis of obviousness under 35 U.S.C. § 103 can be conducted by identifying combinations of prior art references explicitly mentioned within the patent and explaining the motivation a person having ordinary skill in the art (PHOSITA) would have to combine them. The analysis relies on the detailed descriptions within the "Definitions" and "Description" sections of US11261151 as the source for prior art information, as no external prior art documents were provided in a dedicated "Prior Art section" beyond keywords.

Prior Art References from US11261151:

The patent text itself references the following as known prior art:

1. Fauq et al., Bioorg Med Chem Lett. 2010 May 15; 20(10):3036-3038: Discloses endoxifen hydrochloride.
2. U.S. Pat. No. 9,333,190 and U.S. Publication No. 2010/0112041: Disclose endoxifen citrate salts.
3. U.S. Publication No. 2002/0127665: Describes general methods of making gluconate salts of therapeutic agents.
4. European Patent Application No. 168175: Reports the use of the McMurry reaction to prepare tamoxifen.
5. Dickschen et al. Front Pharmacol. 2012; 3: 92. PMCID: PMC3357105: Discusses cytochrome P450 (CYP) mutations causing reduced conversion of tamoxifen to endoxifen, leading to reduced tamoxifen efficacy and increased resistance to the drug.

Obviousness Combinations and Motivations:

1. Synthesis of Endoxifen via McMurry Reaction

• Claims likely rendered obvious: Processes for preparing a mixture of (E)-endoxifen and (Z)-endoxifen (compounds of Formula (III)) by coupling the compound of Formula (II) (a structurally related ketone) to propiophenone mediated by a McMurry reaction.
• Prior Art Combination:
  • Prior Art 1 (A): European Patent Application No. 168175 teaches the preparation of tamoxifen using a McMurry reaction.
  • Prior Art 2 (B): General knowledge in the art that endoxifen is a known active metabolite of tamoxifen and is structurally very similar, defined in the patent as "4-hydroxy-N-desmethyl-tamoxifen."
• Motivation to Combine: A PHOSITA would have been motivated to apply the known McMurry reaction, taught by European Patent Application No. 168175 for tamoxifen, to synthesize endoxifen. Given the close structural relationship between tamoxifen and endoxifen, and the fact that endoxifen is a metabolite of tamoxifen, it would be a logical and straightforward approach for a skilled chemist to adapt a proven synthetic route for tamoxifen to produce endoxifen, particularly starting from structurally analogous ketone precursors (such as compound of Formula II and propiophenone mentioned in the patent). The expectation would be that the McMurry coupling would successfully form the necessary carbon-carbon double bond, without requiring undue experimentation.

2. Endoxifen Gluconate Salt Compositions

• Claims likely rendered obvious: Compositions comprising an endoxifen gluconate salt, and methods of making such salts by reacting (Z)-endoxifen with D-gluconate or L-gluconate.
• Prior Art Combination:
  • Prior Art 1 (A): The knowledge that endoxifen is an active therapeutic agent for hormone-dependent disorders.
  • Prior Art 2 (B): Fauq et al. (2010) and U.S. Pat. No. 9,333,190 / US 2010/0112041 demonstrate that endoxifen can form pharmaceutically acceptable salts, specifically hydrochloride and citrate salts.
  • Prior Art 3 (C): U.S. Publication No. 2002/0127665 teaches general methods for making gluconate salts of therapeutic agents.
• Motivation to Combine: A PHOSITA, aware of the therapeutic utility of endoxifen and the existence of various pharmaceutically acceptable endoxifen salts (HCl, citrate), would be motivated to explore other pharmaceutically acceptable salts, such as gluconate salts, to potentially improve properties like solubility, stability, or patient tolerability. Gluconic acid is a commonly used pharmaceutical counterion. The general knowledge of methods for preparing gluconate salts of therapeutic agents (from U.S. Publication No. 2002/0127665) would provide the PHOSITA with a known approach and a reasonable expectation of success in forming an endoxifen gluconate salt. The patent itself notes, "Methods of making gluconate salts of therapeutic agents are known in the art (for example, U.S. Publication No. 2002/0127665)."

3. Methods of Treating Tamoxifen-Refractory or SSRI-Treated Patients with Endoxifen

• Claims likely rendered obvious: Methods of treating subjects having tamoxifen-refractory or tamoxifen-resistant hormone-dependent disorders, or subjects who are or will be treated with an SSRI drug, by administering an endoxifen composition.
• Prior Art Combination:
  • Prior Art 1 (A): The established use of tamoxifen for hormone-dependent breast and reproductive tract cancers.
  • Prior Art 2 (B): The knowledge that endoxifen is the active metabolite of tamoxifen.
  • Prior Art 3 (C): Dickschen et al. (2012) details that CYP mutations can lead to reduced conversion of tamoxifen to endoxifen, decreasing tamoxifen's efficacy and increasing resistance. The patent further explains that certain SSRIs (e.g., citalopram, escitalopram, fluoxetine, paroxetine, sertraline, and vilazodone) can inhibit the CYP2D6 enzyme, which is crucial for the conversion of N-desmethyl tamoxifen to endoxifen.
• Motivation to Combine: A PHOSITA facing the known problem of tamoxifen resistance or reduced efficacy in certain patient populations (e.g., those with CYP2D6 mutations or those concomitantly taking CYP2D6-inhibiting SSRIs) would be highly motivated to administer the active metabolite, endoxifen, directly. The patent explicitly identifies the problem: "Several cytochrome P450 (CYP) mutations have been proposed to cause reduced conversion of tamoxifen to its active metabolite, endoxifen, and reduce tamoxifen efficacy and increase resistance to the drug." Therefore, bypassing the problematic metabolic step by administering endoxifen directly to these patients would be an obvious solution to a known problem.

Areas Less Susceptible to Obviousness (Based on Limited Prior Art):

• Specific Crystalline Forms: The patent claims novel crystalline Forms I, II, and III of the compound of Formula (III), characterized by specific X-ray powder diffraction (XRPD) patterns. The provided prior art references do not disclose these specific polymorphic forms or methods that would inherently and predictably produce them. While the general goal of identifying and characterizing polymorphs for improved drug properties is known, the discovery of specific, non-obvious crystal forms with advantageous properties (e.g., improved bioavailability, stability) would typically not be rendered obvious without prior art teaching those specific forms or a clear and predictable path to their discovery.
• Specific Pharmacokinetic Profiles (if unexpected): The patent claims compositions achieving particular pharmacokinetic profiles, such as a mean half-life of endoxifen between 30 and 60 hours, a steady-state plasma level of 25-300 nM, and specific AUC values. While optimizing PK profiles is a routine endeavor in drug development, if these specific ranges represent unexpected improvements or solve a previously unrecognized problem, they might be non-obvious. However, if these profiles are merely the expected result of known formulation strategies (e.g., enteric/delayed release, as claimed in the patent), then the claims might be more susceptible to an obviousness challenge depending on the predictability of the results.

It is important to note that a full and conclusive obviousness analysis would typically require access to the complete text of all claims of US11261151 and the full content of the cited prior art documents to compare specific features and teachings in detail.