Mechanism of Action: Thyroid Hormone Synthesis Inhibitors

Drugs with Mechanism of Action: Thyroid Hormone Synthesis Inhibitors

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Actavis Elizabeth	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	080172-001	Approved Prior to Jan 1, 1982	BD	RX	No	No
Chartwell Molecular	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	080016-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Endo Operations	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	006188-001	Approved Prior to Jan 1, 1982	AB	RX	Yes	Yes
Macleods Pharms Ltd	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	208867-001	May 10, 2023	AB	RX	No	No
Macleods Pharms Ltd	METHIMAZOLE	methimazole	TABLET;ORAL	209827-002	May 24, 2023	AB	RX	No	No
Quagen	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	080154-001	Approved Prior to Jan 1, 1982	BD	RX	No	No

yroid Hormone Synthesis Inhibitors: Market Dynamics and Patent Landscape
The thyroid hormone synthesis inhibitors market is a critical segment in endocrine therapeutics, addressing conditions like hyperthyroidism and Graves' disease. With a projected growth from $2.4 billion in 2023 to $2.75 billion by 2028 (CAGR 2.8%)[1][7], this market is driven by rising thyroid disorder prevalence, drug innovation, and evolving healthcare infrastructure. Concurrently, a dynamic patent landscape—marked by formulation advancements and impending expirations—shapes competition and accessibility. Below, we explore key trends, clinical developments, and strategic shifts defining this sector.

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Global Market Overview

Market Size and Growth Projections

The global anti-thyroid drugs market grew from $2.4 billion in 2023 to $2.46 billion in 2024 (CAGR 2.5%)[1], with steady expansion expected to $2.75 billion by 2028[1][7]. Parallel reports highlight a potential rise to $1.85 billion by 2033 (CAGR 5.0%) for hyperthyroidism-specific therapies[13], reflecting nuanced segmentation across conditions like Graves' disease and thyroid cancer.

Key Market Drivers

• Rising Thyroid Disorder Prevalence: Over 200 million people globally suffer from thyroid diseases[13], with Graves' disease responsible for 40% of hyperthyroidism cases[2].
• Drug Innovations: Liquid levothyroxine (e.g., Tirosint-SOL) and monoclonal antibodies like TEPEZZA address compliance and efficacy gaps[3][4].
• Healthcare Expenditure: Increased investment in endocrine care and telemedicine supports market penetration[1][13].

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Mechanism of Action: How Thyroid Inhibitors Work

Thyroid hormone synthesis inhibitors suppress hormone production via two primary mechanisms:

1. Thionamides (e.g., methimazole, propylthiouracil): Inhibit thyroid peroxidase (TPO), blocking iodine incorporation into thyroglobulin[9][12].
2. Iodides (e.g., potassium iodide): Reduce hormone release by saturating thyroid follicles[7].

Propylthiouracil uniquely inhibits peripheral conversion of thyroxine (T4) to triiodothyronine (T3)[9][14], whereas methimazole offers 10x greater potency[12].

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Major Drugs in the Market

Methimazole

• Mechanism: TPO inhibition, preventing thyroglobulin iodination[12].
• Advantage: Preferred over PTU due to lower hepatotoxicity risk[12].
• Market: Patents like CN107353253A optimize synthesis, while generics dominate post-expiry markets[11][17].

Propylthiouracil (PTU)

• Use Case: Pregnancy (lower teratogenicity risk) and severe thyrotoxicosis[12].
• Innovation: Sustained-release pellets (CN102764239B) enhance compliance[16].

Levothyroxine Formulations

• Tirosint-SOL: FDA-approved liquid levothyroxine bypasses absorption issues caused by food or antacids[3].

"Liquid levothyroxine overcomes limitations of traditional tablets, particularly for patients with swallowing difficulties."
—Arturo Licenziati, President of IBSA[3]

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Emerging Therapies and Innovations

TEPEZZA (Teprotumumab)

Attribute	Detail
Indication	Thyroid Eye Disease (TED)
Mechanism	IGF-1R inhibitor
2023 Market	$2.3 billion (7 major markets)[4]
Competitor	Batoclimab (anticipated 2025–2026)[4]

Pipeline Developments

• TSHR Antagonists: Patent US10596168B2 targets Graves' disease via TSH receptor blockade[2].
• AXL/MER Inhibitors: Repurposed oncology drugs show potential in thyroid cancer[6].

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Patent Landscape Analysis

Key Patents and Innovations

1. TSHR Antagonists: Heterocyclic compounds (US10596168B2) for autoimmune thyroid disorders[2].
2. Synthesis Methods: CN107353253A streamlines methimazole production[11], while US11564926B2 covers thyroid hormone analog synthesis[8].
3. Formulation Patents: Tirosint-SOL’s liquid delivery system[3] and PTU sustained-release pellets[16].

Impact of Patent Expirations

• Generics Entry: Methimazole generics (e.g., Bionpharma, Qingdao Baheal) captured 30%–50% market share post-2020[17].
• Revenue Erosion: Branded drugs face 60%–80% revenue drops within 2 years of patent expiry[10].

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Competitive Landscape

Leading Pharmaceutical Companies

• Top Players: Mylan N.V., AbbVie Inc., GlaxoSmithKline, and Merck & Co.[1][7].
• Strategic Moves: Amgen’s acquisition of TEPEZZA developer Horizon Therapeutics (2023) strengthened its endocrine portfolio[4].

Generic Drug Market Entry

• Methimazole: 15+ manufacturers compete in the U.S., driving prices down by 70%[17].
• PTU: Limited generics due to niche use but growing in Asia-Pacific[16].

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Challenges and Market Restraints

• Side Effects: Agranulocytosis (1 in 500–1000 PTU users) and hepatotoxicity[14].
• Cost Barriers: Annual treatment costs exceed $1,500 in low-income regions[13].
• Regulatory Hurdles: Delays in OTC approvals for thyroid drugs[5].

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Future Outlook and Opportunities

• Personalized Therapies: Biomarker-driven dosing for Graves’ disease[2].
• Digital Health: Telemedicine platforms improving rural access to endocrinologists[1].
• Biosimilars: TEPEZZA biosimilars expected post-2030[4].

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Key Takeaways

1. The anti-thyroid drugs market grows steadily (CAGR 2.5%–5.0%), fueled by Graves' disease and thyroid cancer.
2. Methimazole and PTU remain cornerstones, with innovations like Tirosint-SOL enhancing compliance.
3. Patent expirations accelerate generics, reshaping competitive dynamics by 2030.
4. TEPEZZA dominates the $2.3 billion TED market, with batoclimab poised to disrupt it.

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FAQs

1. What drives the growth of thyroid hormone inhibitors?
Rising thyroid disorder prevalence, drug innovations (e.g., TEPEZZA), and healthcare investment[1][4][13].

2. How do methimazole and PTU differ?
Methimazole is 10x more potent with fewer side effects, while PTU is preferred in pregnancy[9][12].

3. What happens when anti-thyroid drug patents expire?
Generics enter the market, reducing prices by 70% and eroding branded drug revenue[10][17].

4. Which companies lead this market?
Mylan, AbbVie, Amgen, and Horizon Therapeutics (TEPEZZA)[1][4].

5. What are emerging therapies to watch?
Batoclimab for TED and TSHR antagonists for Graves’ disease[2][4].

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“The FDA approval of Tirosint-SOL opens opportunities in a market of 18 million patients.”

— Arturo Licenziati, President of IBSA[3]

References

1. https://www.einpresswire.com/article/737362693/global-anti-thyroid-drugs-market-overview-and-statistics-for-2024-2033
2. https://patents.justia.com/patent/10596168
3. https://www.biospace.com/the-fda-has-approved-tirosint-sol-levothyroxine-in-liquid-solution-for-the-american-market-b-ibsa-b-patent
4. https://www.globenewswire.com/news-release/2025/02/19/3029065/0/en/TEPEZZA-Market-Sales-on-the-Rise-Due-to-the-Strong-Growth-Driven-by-Demand-for-Thyroid-Eye-Disease-Treatment-DelveInsight.html
5. https://www.aeaweb.org/conference/2022/preliminary/paper/h3hseFFr
6. https://www.research.ed.ac.uk/files/22230049/AXL_Inhibitors_in_Cancer.pdf
7. https://www.thebusinessresearchcompany.com/report/anti-thyroid-drugs-global-market-report
8. https://patents.google.com/patent/US11564926B2/en
9. https://go.drugbank.com/drugs/DB00550
10. https://www.qualifyze.com/resources/blog/understanding-the-financial-implications-of-patent-expirations
11. https://patents.google.com/patent/CN107353253A/en
12. https://go.drugbank.com/drugs/DB00763
13. https://www.verifiedmarketreports.com/product/anti-thyroid-drugs-market/
14. https://www.pharmacy180.com/article/thyroid-inhibitors-1040/
15. https://patents.google.com/patent/US6365616B1/en
16. https://patents.google.com/patent/CN102764239B/en
17. https://www.drugpatentwatch.com/p/generic/methimazole