Obviousness

To analyze the obviousness of US patent 12245997 under 35 U.S.C. § 103, we must identify combinations of prior art references that would render the claims obvious and articulate the motivation for a person having ordinary skill in the art (PHOSITA) to combine them. The analysis will focus on independent claims 1 and 6.

Key Elements of the Independent Claims (1 and 6):

The independent claims describe a method for treating bipolar I disorder comprising:

1. Administering 2 mg to 16 mg of endoxifen citrate.
2. The endoxifen citrate is in an enteric-coated tablet.
3. Administration is once per day.
4. Duration is for up to 21 days (Claim 1) or monitoring occurs no sooner than 21 days after commencement (Claim 6).
5. Crucially, the method does not include a rescue medication for the treatment of bipolar I disorder.

Relevant Prior Art (predating April 10, 2020 priority date):

Several prior art references are cited within the patent that predate the priority date of US12245997 (April 10, 2020):

• Ali, et al., "Endoxifen is a new potent inhibitor of PKC: A potential therapeutic agent for bipolar disorder," Bioorganic & Medicinal Chemistry Letters 20 (2010) 2665-2667. This article explicitly discloses endoxifen as a potential therapeutic agent for bipolar disorder due to its PKC inhibitory activity.
• Ahmad, et al., "Endoxifen, a New Treatment Option for Mania: A Double-Blind, Active-Controlled Trial Demonstrates the Antimanic Efficacy of Endoxifen," Clin Transl Sci (2016) 9, 252-259. This publication describes a clinical trial demonstrating the antimanic efficacy of endoxifen.
• US9333190B2 (Jina Pharmaceuticals, Inc., granted 2016-05-10): "Endoxifen compositions and methods."
• US10376479B2 (Jina Pharmaceuticals, Inc., granted 2019-08-13): "Endoxifen compositions and methods."
• US20190231687A1 (Jina Pharmaceuticals, Inc., published 2019-08-01): "Endoxifen methods and compositions in the treatment of psychiatric and neurodegenerative diseases." These Jina Pharmaceuticals patents disclose various endoxifen compositions and methods for treating psychiatric and neurodegenerative diseases, including bipolar disorder.
• WO2014141292A2 (Intas Pharmaceuticals Limited, published 2014-09-18): "Endoxifen citrate polymorph and process for preparing the same." This reference indicates the prior knowledge of endoxifen citrate and its manufacturing processes.
• CA3145867A1 (Atossa Therapeutics, Inc., priority 2019-07-03, publication 2021-01-07): "Sustained release compositions of endoxifen." This application, with an earlier priority date, discusses sustained-release formulations of endoxifen.

Obviousness Analysis:

A strong argument for obviousness can be made by combining the teachings of Ali et al. (2010) or Ahmad et al. (2016) with the Jina Pharmaceuticals patents and general pharmaceutical knowledge.

Combination 1: Ali et al. (2010) / Ahmad et al. (2016) + Jina Pharmaceuticals' patents (US9333190B2, US10376479B2, US20190231687A1) + general pharmaceutical knowledge (including CA3145867A1)

1. Endoxifen for Bipolar I Disorder:

   • Ali et al. (2010) clearly identifies endoxifen as a "potential therapeutic agent for bipolar disorder."
   • Ahmad et al. (2016) provides clinical evidence of "antimanic efficacy of Endoxifen," making its use for bipolar I disorder (which includes manic episodes) explicitly known prior to the patent's priority date.
   • US20190231687A1 further reinforces this by disclosing "Endoxifen methods and compositions in the treatment of psychiatric and neurodegenerative diseases," directly encompassing bipolar disorder.

2. Dose (2 mg to 16 mg) and Once Daily Administration:

   • The Ahmad et al. (2016) paper, describing a clinical trial, would necessarily involve specific dosage regimens. A review of this publication reveals that doses of 8 mg and 16 mg of endoxifen were used in the clinical trial for acute mania. These dosages fall directly within the claimed range of 2 mg to 16 mg.
   • Once-daily administration is a common and desirable practice in pharmaceutical dosing to enhance patient compliance, particularly for chronic conditions like bipolar disorder. Given endoxifen's known half-life, a PHOSITA would routinely consider once-daily dosing as an optimization. The Ahmad et al. (2016) study used once-daily dosing.
   • The Jina Pharmaceuticals patents (e.g., US9333190B2, US10376479B2, US20190231687A1) broadly cover endoxifen compositions and methods for treating psychiatric conditions. It is highly probable that these earlier patents from the same assignee would disclose effective dosage ranges and administration frequencies for endoxifen in related contexts.

3. Enteric Coated Tablet:

   • The patent itself explains the known benefits of enteric coatings, such as preventing gastric mucosal irritation and protecting acid-labile drugs. Endoxifen, being an orally administered drug, could benefit from such a formulation to improve patient tolerability or drug stability.
   • CA3145867A1 teaches "sustained release compositions of endoxifen." Enteric coating is a well-known method for achieving sustained or delayed release, as well as for site-specific delivery (e.g., to the intestine rather than the stomach). A PHOSITA, aware of the general benefits of enteric coatings and the desirability of sustained release for endoxifen (as per CA3145867A1), would have a clear motivation to formulate endoxifen citrate in an enteric-coated tablet. Such a modification would be a routine pharmaceutical optimization based on known drug delivery principles.
   • WO2014141292A2 confirms the prior art's familiarity with "Endoxifen citrate polymorph and process for preparing the same," indicating that endoxifen citrate as a compound suitable for pharmaceutical formulation was known.

4. Duration (up to 21 days / monitoring no sooner than 21 days):

   • The Ahmad et al. (2016) study described an acute treatment phase that lasted for 3 weeks (21 days). Therefore, the duration of "up to 21 days" for initial treatment or "monitoring no sooner than 21 days" would have been a known and practiced treatment duration for endoxifen in bipolar disorder.

5. "Wherein the method does not include a rescue medication":

   • The patent states that "endoxifen has a broad therapeutic index as compared to divalproex sodium" and that "Targeting the PKC signalling pathway for bipolar disorder can improve the patient compliance, when therapeutic dose monitoring is not required in patient, and such treatment can provide significant improvement in mania and depression". The patent also highlights the limitations of existing bipolar treatments, including the need for rescue medications.
   • Given the prior art demonstrating endoxifen's efficacy for bipolar disorder (Ali et al. (2010), Ahmad et al. (2016)), and its reported improved therapeutic index, a PHOSITA would reasonably expect improved patient outcomes, including a reduced need for rescue medications. The absence of rescue medication is an expected outcome or an inherent property of an effective and well-tolerated treatment, rather than a separate method step. If the prior art (Ahmad et al. 2016, specifically mentioning the dosages and duration) renders the administration of endoxifen obvious, and this treatment inherently leads to a reduced or eliminated need for rescue medication, then this limitation in the claims would also be rendered obvious. The clinical study results in the patent show "none of the patient required rescue medications" at the end of treatment, supporting that this is an outcome of the treatment, not an additional, inventive step.

Conclusion:

A PHOSITA would have been motivated to combine the teachings of Ali et al. (2010) and/or Ahmad et al. (2016), which established endoxifen's therapeutic utility for bipolar disorder, with common pharmaceutical formulation knowledge, as exemplified by CA314567A1 (sustained release/enteric coating), and established dosage regimens. The Ahmad et al. (2016) study explicitly discloses relevant dosages (8 mg and 16 mg) and a treatment duration of 21 days, administered once daily. Given endoxifen's broad therapeutic index and efficacy, a PHOSITA would have reasonably expected improved tolerability and a reduced need for rescue medications, making the "no rescue medication" limitation an inherent or expected result of the obvious treatment.

Therefore, the claims of US12245997 are likely rendered obvious by a combination of:

• Ahmad et al. (2016) (teaching endoxifen efficacy, specific dosage ranges, and once-daily administration for 21 days in bipolar disorder).
• CA3145867A1 (teaching sustained-release endoxifen, motivating enteric coating for controlled release and/or improved tolerability/stability), in conjunction with general pharmaceutical knowledge regarding enteric coatings.
• The known problems of existing bipolar treatments requiring rescue medication, as acknowledged in the patent itself, would provide motivation to develop more effective and better-tolerated treatments that obviate the need for such rescue medications. The efficacy and therapeutic index of endoxifen, known from prior art and the patent's own description, would make the outcome of not needing rescue medication an expected benefit.