A Study to Assess the Safety and Efficacy of Oral Armour Thyroid Compared to Synthetic T4 for the Treatment of Primary Hypothyroidism in Adult Participants
About the study
This study will evaluate the efficacy and safety of Armour Thyroid treatment compared with synthetic T4 in subjects who have primary hypothyroidism and are currently stabilized (i.e., in-range thyroid-stimulating hormone \[TSH\]) on synthetic T4 treatment. This study will also therefore evaluate the efficacy and safety of dose conversion from synthetic T4 therapy to Armour Thyroid therapy.
Who can take part
You may be eligible to participate in the study if you meet the following criteria:
INCLUSION CRITERIA
Inclusion Criteria:
- Have a diagnosis of primary hypothyroidism made >= 12 months prior to Screening.
- Be on continuous thyroid replacement therapy of synthetic T4 for primary hypothyroidism for at least 12 months immediately prior to the Screening Visit.
- Be on a stable FDA-approved daily dose of synthetic T4 prior to the Screening visit, and must be taking synthetic T4 dose of at least 25 mcg at Screening visit. Must enter the study using the same stable dose to determine dose conversion.
- Documentation of 1 in-range thyroid-stimulating hormone (TSH) (i.e., within 0.45 - 4.12 mIU/L, inclusive) at Screening and at least 1 additional in range TSH (i.e., within 0.45 - 4.12 mIU/L, inclusive) taken at a minimum of 6 weeks and a maximum of 12 months prior to Screening.
EXCLUSION CRITERIA
Exclusion Criteria:
- Any clinical condition or previous surgery that might affect the absorption, distribution, biotransformation, or excretion of Armour Thyroid or synthetic T4.
- History of alcohol or other substance abuse within the previous 6 months prior to the Screening.
- Known or suspected allergy or intolerance to any ingredients of Armour Thyroid, including its excipients, synthetic T4, other thyroid replacement medications, or pork products.

Study Locations
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How to Apply
Contact the study center to learn if this study is a good match for you.
Study’s details
Contition
Hypothyroidism
Age
18 - 75
Phase
PHASE2/PHASE3
Participants needed
2800
Est. Completion Date
Jun 30, 2028
Treatment type
INTERVENTIONAL
Sponsor
AbbVie
ClinicalTrials.gov identifier
NCT06345339
Study number
M21-341
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