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Pyridazinone Compounds as Thyroid Hormone Analogs Synthesis Methods

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Published March 18th, 2026
Detected March 23rd, 2026
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Summary

The European Patent Office has published a patent application detailing new synthesis methods for pyridazinone compounds, which act as thyroid hormone analogs. These methods aim to improve purity, yield, and scalability for large-scale preparation, and also describe morphic forms and a treatment method for thyroid hormone resistance.

What changed

The European Patent Office (EPO) has published patent application EP4691557A3, which describes novel synthesis methods for pyridazinone compounds that function as thyroid hormone analogs. The application, filed by Madrigal Pharmaceuticals, Inc. and F. Hoffmann-La Roche Ltd, highlights preferred methods for large-scale preparation with high purity and improved yield compared to existing techniques. It also covers specific morphic forms of these compounds and a method for treating thyroid hormone resistance in subjects with TRP mutations.

This publication represents a new disclosure of intellectual property related to pharmaceutical synthesis and treatment. While it is a patent application and not a binding regulation, it provides detailed technical information that could influence future drug development and manufacturing processes. Companies involved in the synthesis or therapeutic use of thyroid hormone analogs should review this patent to understand potential new methodologies and claims, particularly concerning large-scale production and specific therapeutic applications.

What to do next

  1. Review patent application EP4691557A3 for potential impact on synthesis methods and therapeutic applications.
  2. Assess current manufacturing processes for pyridazinone compounds against disclosed methods for purity and yield improvements.
  3. Evaluate potential for new morphic forms and their implications for drug formulation and stability.

Source document (simplified)

← EPO Patent Bulletin

METHOD OF SYNTHESIZING THYROID HORMONE ANALOGS AND POLYMORPHS THEREOF

Search Report EP4691557A3 Kind: A3 Mar 18, 2026

Applicants

Madrigal Pharmaceuticals, Inc., F. Hoffmann-La Roche Ltd

Inventors

HESTER, Keith D., DUGUID, Robert J., KELLY, Martha, CHASNOFF, Anna, DONG, Gang, CROW, Edwin L., TAUB, Rebecca, REYNOLDS, Charles H., CHOI, Duk Soon, SHU, Lianhe, WANG, Ping

Abstract

The disclosure describes methods of synthesis of pyridazinone compounds as thyroid hormone analogs and their prodrugs. Preferred methods according to the disclosure allow for large-scale preparation of pyridazinone compounds having high purity. In some embodiments, preferred methods according to the disclosure also allow for the preparation of pyridazinone compounds in better yield than previously used methods for preparing such compounds. Also disclosed are morphic forms of a pyridazinone compound. Further disclosed is a method for treating resistance to thyroid hormone in a subject having at least one TRP mutation.

IPC Classifications

C07D 237/16 20060101AFI20260206BHEP A61K 31/50 20060101ALI20260206BHEP A61P 3/00 20060101ALI20260206BHEP A61P 9/00 20060101ALI20260206BHEP

Designated States

AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LI, LT, LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, SM, TR

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Named provisions

METHOD OF SYNTHESIZING THYROID HORMONE ANALOGS AND POLYMORPHS THEREOF

Classification

Agency
EPO
Published
March 18th, 2026
Instrument
Guidance
Legal weight
Non-binding
Stage
Final
Change scope
Substantive
Document ID
EP4691557A3

Who this affects

Applies to
Drug manufacturers Pharmaceutical companies
Industry sector
3254 Pharmaceutical Manufacturing
Activity scope
Drug Synthesis Therapeutic Treatment
Geographic scope
European Union EU

Taxonomy

Primary area
Pharmaceuticals
Operational domain
Research & Development
Topics
Drug Development Medical Treatments

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