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

Recruitment Status
RECRUITING
(See Contacts and Locations)Verified November 2025 by AbbVie
Sponsor
AbbVie
Information Provided by (Responsible Party)
AbbVie
Clinicaltrials.gov Identifier
NCT06345339
Other Study ID Numbers:
M21-341
First Submitted
March 26, 2024
First Posted
April 2, 2024
Last Update Posted
January 4, 2026
Last Verified
November 2025

ClinicalTrials.gov processed this data on December 2025. Link to the current ClinicalTrials.gov record .

History of Changes

Study Details

Study Description

Condition or DiseaseIntervention/Treatment
Hypothyroidism
Drug: Armour ThyroidDrug: Armour Thyroid

Study Design

Study TypeInterventional
Actual Enrollment2800 participants
Design AllocationRandomized
Interventional ModelParallel Assignment
MaskingTriple
Primary PurposeTreatment
Official TitleA Phase 2/3 Multicenter, Double Blinded, Randomized, Dose-conversion, Active Control Study Examining the Efficacy and Safety of Armour Thyroid Compared to Synthetic T4 for the Treatment of Adults With Primary Hypothyroidism
Study Start DateApril 25, 2024
Actual Primary Completion Date1yr 3mos from now
Actual Study Completion Date2yrs 1w from now

Groups and Cohorts

Group/CohortIntervention/Treatment
Group 1
Participants will receive Armour Thyroid for up to 81 weeks.
Drug: Armour Thyroid
Oral Capsule or Tablet
Group 2
Participants will alternate between Armour Thyroid and synthetic T4 for up to 81 weeks.
Drug: Armour Thyroid
Oral Capsule or Tablet

Outcome Measures

Primary Outcome Measures
  1. Percentage of Participants who Achieve Thyroid-Stimulating Hormone (TSH) Response
    TSH response is defined as TSH values falling within 0.45 to 4.12 mIU/L (inclusive). TSH response will be determined at Week 55 and at a prior visit with no out-of-range TSH values in between (response rate is tested against a specified non-inferiority margin).
  2. Number of Participants with Adverse Events (AEs)
    An AE is defined as any untoward medical occurrence in a patient or clinical investigation in which a participant is administered a pharmaceutical product which does not necessarily have a causal relationship with this treatment.
Secondary Outcome Measures
  1. Percentage of Participants who Achieve TSH Response
    TSH response is defined as TSH values falling within 0.45 to 4.12 mIU/L. TSH response will be determined at Week 55 and at a prior visit with no out-of-range TSH values in between (response rate is tested against a specified non-inferiority margin \[stricter than the one used in the Primary Outcome Measure\]).
  2. Number of Participants Needing Altered Dose Conversion from Synthetic T4 to Armour Thyroid
    Number of participants needing altered dose conversion from synthetic T4 to Armour Thyroid.
  3. Frequency of Dose Titrations During the Double-Blind (DB) Period Among Participants who Achieved TSH Response at the End of the DB Period
    Frequency of dose titrations (0,1,2...) during the DB period among participants who achieved TSH response at the end of the DB period.

Eligibility Criteria

Ages Eligible for Study(Adult, Older Adult)
Sexes Eligible for StudyAll
Accepts Healthy VolunteersNo
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
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.

Contacts and Locations

Sponsors and CollaboratorsAbbVie
Locations
Central Research Associates /ID# 255719 | Birmingham Alabama, United States, 35205UAB Hospital /ID# 262565 | Birmingham Alabama, United States, 35233-1932Kaiser San Diego Dept Endocrinology, SCPMG /ID# 262552 | Bonita California, United States, 91902-1230Facey Medical Foundation - Burbank /ID# 262104 | Burbank California, United States, 91505-4554John Muir Medical Center /ID# 257103 | Concord California, United States, 94520Diagnamics Inc. /ID# 262680 | Encinitas California, United States, 92024Providence - St. Jude Medical Center /ID# 256520 | Fullerton California, United States, 92835NorCal Medical Research /ID# 256512 | Greenbrae California, United States, 94904Velocity Clinical Research - Huntington Park /ID# 259044 | Huntington Park California, United States, 90255-2951Scripps Whittier Diabetes Institute /ID# 259215 | La Jolla California, United States, 92037Facey Medical Foundation /ID# 260863 | Mission Hills California, United States, 91345Hoag Memorial Hospital Presbyterian /ID# 260990 | Newport Beach California, United States, 92663Diabetes Associates Medical Group /ID# 256949 | Orange California, United States, 92866-2862Western University of Health Sciences /ID# 262183 | Pomona California, United States, 91766Research at Mills-Peninsula Medical Center - Sutter Health /ID# 258825 | San Mateo California, United States, 94404Care Access - Santa Clarita /ID# 262573 | Santa Clarita California, United States, 91321Facey Medical Foundation - Valencia /ID# 262102 | Santa Clarita California, United States, 91355-4462Olive View UCLA Medical Center /ID# 259092 | Sylmar California, United States, 91342-1437The Lundquist Institute at Harbor-UCLA Medical Center /ID# 262572 | Torrance California, United States, 90502Diablo Clinical Research /ID# 261329 | Walnut Creek California, United States, 94598San Fernando Valley Health Institute /ID# 257363 | West Hills California, United States, 91304-3837New England Research Associates - Bridgeport /ID# 262184 | Bridgeport Connecticut, United States, 06606Innovative Research of West Florida /ID# 257356 | Clearwater Florida, United States, 33756-2004ALL Medical Research /ID# 256748 | Cooper City Florida, United States, 33024Northeast Research Institute (NERI) /ID# 261841 | Fleming Island Florida, United States, 32003Northeast Research Institute (NERI) /ID# 261846 | Fleming Island Florida, United States, 32003The Center for Diabetes and Endocrine Care /ID# 255721 | Fort Lauderdale Florida, United States, 33312Encore Medical Research LLC /ID# 256758 | Hollywood Florida, United States, 33021East Coast Institute For Research - LaVilla - West Monroe Street /ID# 256972 | Jacksonville Florida, United States, 32204The University of Florida Heal /ID# 257361 | Jacksonville Florida, United States, 32207-4966East Coast Research - Jacksonville /ID# 256971 | Jacksonville Florida, United States, 32216Encore Research Group-Jacksonville Center for Clinical Research /ID# 256147 | Jacksonville Florida, United States, 32216Baptist Health Research Institute /ID# 260989 | Jacksonville Florida, United States, 32258South Florida Wellness & Clinic /ID# 256513 | Margate Florida, United States, 33063Med Research of Florida /ID# 257837 | Miami Florida, United States, 33186Ocean Blue Medical Research Center, Inc /ID# 260438 | Miami Springs Florida, United States, 33166Adult Medicine of Lake County - Mount Dora /ID# 257371 | Mt. Dora Florida, United States, 32757Suncoast Clinical Research Pasco County /ID# 257018 | New Port Richey Florida, United States, 34652West Orange Endocrinology /ID# 256139 | Ocoee Florida, United States, 34761-4547Suncoast Clinical Research - Palm Harbor /ID# 256741 | Palm Harbor Florida, United States, 34684Comprehensive Medical & Research Center /ID# 261678 | Plantation Florida, United States, 33317-2911Northeast Research Institute - St. Augustine /ID# 261857 | Saint Augustine Florida, United States, 32080Metabolic Research Inst /ID# 255729 | West Palm Beach Florida, United States, 33401Grady Clinical Research Center Grady Memorial Hospital /ID# 258419 | Atlanta Georgia, United States, 30303Atlanta Diabetes Associates /ID# 255736 | Atlanta Georgia, United States, 30318East Coast Institute for Research - Canton /ID# 256974 | Canton Georgia, United States, 30114Centricity Research - Endocrine Consultants Research /ID# 255738 | Columbus Georgia, United States, 31904Physicians Research Associates, LLC /ID# 255675 | Lawrenceville Georgia, United States, 30046The Jones Center Clinical Research /ID# 256529 | Macon Georgia, United States, 31210Endocrine Research Solutions /ID# 256784 | Roswell Georgia, United States, 30076Pacific Diabetes & Endocrine Center /ID# 259030 | Honolulu Hawaii, United States, 96813Rocky Mountain Clinical Research, LLC /ID# 256753 | Idaho Falls Idaho, United States, 83404-7596Northwestern University Feinberg School of Medicine /ID# 260677 | Chicago Illinois, United States, 60611-2927West Broadway Clinic /ID# 256756 | Council Bluffs Iowa, United States, 51501-3822Iowa Diabetes and Endocrinology Research Center /ID# 256750 | West Des Moines Iowa, United States, 50266Cotton O'Neil Diabetes & Endocrinology /ID# 256749 | Topeka Kansas, United States, 66606University of Louisville Hospital /ID# 262568 | Louisville Kentucky, United States, 40202Robley Rex VA Medical Center /ID# 262569 | Louisville Kentucky, United States, 40206L-MARC Research Center /ID# 255733 | Louisville Kentucky, United States, 40213-1014Pennington Biomedical Research Center /ID# 262390 | Baton Rouge Louisiana, United States, 70808Nola Care Clinical Research /ID# 260145 | Metairie Louisiana, United States, 70006-2930Omega Clinical Research /ID# 260162 | Metairie Louisiana, United States, 70006-2930Tufts Medical Center /ID# 262974 | Boston Massachusetts, United States, 02111-1552Circle Health Diabetes and Endocrine Center /ID# 270461 | Dracut Massachusetts, United States, 01826NECCR PrimaCare Research, LLC /ID# 256531 | Fall River Massachusetts, United States, 02721Metro Detroit Endocrinology Center /ID# 260862 | Dearborn Michigan, United States, 48126Michigan Healthcare Professionals /ID# 260859 | Farmington Hills Michigan, United States, 48334Elite Clinical Research Center /ID# 256782 | Flint Michigan, United States, 48532Diabetes and Endocrinology Specialists /ID# 259068 | Chesterfield Missouri, United States, 63017University of Missouri Hospital /ID# 262562 | Columbia Missouri, United States, 65212Jefferson City Medical Group /ID# 257099 | Jefferson City Missouri, United States, 65109Mercy Research - Springfield /ID# 262385 | Springfield Missouri, United States, 65804St. Louis University /ID# 262375 | St Louis Missouri, United States, 63104Washington University-School of Medicine /ID# 262391 | St Louis Missouri, United States, 63110Billings Clinic /ID# 258316 | Billings Montana, United States, 59101-0733Mercury Street Medical /ID# 259632 | Butte Montana, United States, 59701-1652Bryan Health Pine Lake Campus /ID# 259638 | Lincoln Nebraska, United States, 68516Methodist Physicians Clinic /ID# 259276 | Omaha Nebraska, United States, 68114Palm Research Center /ID# 256131 | Las Vegas Nevada, United States, 89148Northern Nevada Endocrinology /ID# 259646 | Reno Nevada, United States, 89511Southern New Hampshire Diabetes and Endocrinology /ID# 257841 | Nashua New Hampshire, United States, 03060Albany Medical College- Endocrinology Washington Extension /ID# 256794 | Albany New York, United States, 12203Research Foundation of SUNY - University of Buffalo /ID# 261019 | Buffalo New York, United States, 14203NYC Research /ID# 258662 | New York New York, United States, 10001Endocrine Assc Long Island PC /ID# 257357 | Smithtown New York, United States, 11787Physician's East Endocrinology /ID# 256491 | Greenville North Carolina, United States, 27834Carteret Medical Group /ID# 256869 | Morehead City North Carolina, United States, 28557Lucas Research /ID# 256127 | Morehead City North Carolina, United States, 28557Lucas Research /ID# 257061 | Morehead City North Carolina, United States, 28557Accellacare - Salisbury /ID# 257019 | Salisbury North Carolina, United States, 28144-2735Accellacare Wilmington /ID# 256744 | Wilmington North Carolina, United States, 28401Diabetes and Endocrinology Associates of Stark County Inc /ID# 256751 | Canton Ohio, United States, 44718Cleveland Clinic - Cleveland /ID# 262392 | Cleveland Ohio, United States, 44195The Ohio State University Wexner Medical Center - CarePoint East /ID# 264061 | Columbus Ohio, United States, 43203Lynn Institute of Norman /ID# 256785 | Norman Oklahoma, United States, 73072Lynn Institute of Oklahoma City /ID# 263141 | Oklahoma City Oklahoma, United States, 73112Diabetes & Endocrinology Consultants of Pennsylvania /ID# 259064 | Feasterville-Trevose Pennsylvania, United States, 19053Thomas Jefferson University Hospital /ID# 256834 | Philadelphia Pennsylvania, United States, 19107Jefferson Health - Roosevelt Boulevard /ID# 256837 | Philadelphia Pennsylvania, United States, 19114-1025Guthrie Robert Packer Hospital /ID# 261838 | Sayre Pennsylvania, United States, 18840TMA Headlands LLC /ID# 259800 | Myrtle Beach South Carolina, United States, 29572Carolina Endocrine Associates Llc /ID# 259640 | North Charleston South Carolina, United States, 29406-9823Palmetto Clinical Research - Summerville /ID# 258845 | Summerville South Carolina, United States, 29485Chattanooga Medical Research /ID# 257631 | Chattanooga Tennessee, United States, 37404-3239PMG Research of Knoxville /ID# 256854 | Knoxville Tennessee, United States, 37938University of Tennessee Health Science Center /ID# 259825 | Memphis Tennessee, United States, 38103Lifedoc Research /ID# 262975 | Memphis Tennessee, United States, 38115Mid State Endocrine Associates /ID# 259641 | Nashville Tennessee, United States, 37203Texas Diabetes and Endocrinology - Central Austin /ID# 255728 | Austin Texas, United States, 78731Texas Diabetes and Endocrinology - South Austin /ID# 255723 | Austin Texas, United States, 78749Brusco, Corpus Christi, TX /ID# 256746 | Corpus Christi Texas, United States, 78414North TX Endocrine Center /ID# 255737 | Dallas Texas, United States, 75231Research Institute Dallas /ID# 256126 | Dallas Texas, United States, 75231Academy of Diabetes, Thyroid and Endocrine /ID# 255735 | El Paso Texas, United States, 79935Diabetes and Thyroid Center of Ft. Worth /ID# 256781 | Fort Worth Texas, United States, 76132Juno Research /ID# 259238 | Houston Texas, United States, 77040Biopharma Informatic - Houston - Business Center Drive /ID# 256149 | Houston Texas, United States, 77043PlanIt Research, PLLC /ID# 259221 | Houston Texas, United States, 77079-2204Endocrine and Psychiatry Cente /ID# 259631 | Houston Texas, United States, 77095Tekton Research - Irving /ID# 260988 | Irving Texas, United States, 75039Southern Endocrinology Associates /ID# 256795 | Mesquite Texas, United States, 75149Texas Diabetes and Endocrinology /ID# 255722 | Round Rock Texas, United States, 78681Northeast Clinical Research of San Antonio, LLC /ID# 256868 | San Antonio Texas, United States, 78233Diabetes & Glandular Disease Clinic /ID# 255734 | San Antonio Texas, United States, 78237Consano Clinical Research, LLC /ID# 256138 | Shavano Park Texas, United States, 78231Texas Valley Clinical Research /ID# 261476 | Weslaco Texas, United States, 78596Advanced Research Institute /ID# 259821 | Ogden Utah, United States, 84405-6779The University of Vermont Medical Center /ID# 256533 | South Burlington Vermont, United States, 05403Virginia Endocrinology Research /ID# 259623 | Chesapeake Virginia, United States, 23321Richmond VA Medical Center /ID# 262386 | Richmond Virginia, United States, 23249Salem VA Medical Center /ID# 262387 | Salem Virginia, United States, 24153Rainier Clinical Research /ID# 255802 | Renton Washington, United States, 98055MultiCare Rockwood Clinic /ID# 255951 | Spokane Washington, United States, 99202MultiCare Institute for Research & Innovation /ID# 255954 | Tacoma Washington, United States, 98405Clinical Research Investigator Group, LLC /ID# 263177 | Bayamón , Puerto Rico, 00960ISIS Clinical Research Center /ID# 263182 | Guaynabo , Puerto Rico, 00969-2806BRCR Global Puerto Rico /ID# 268231 | San Juan , Puerto Rico, 00907-1510GCM Medical Group, PSC /ID# 263183 | San Juan , Puerto Rico, 00917Mindful Medical Research /ID# 263184 | San Juan , Puerto Rico, 00918-3756
Investigators
Study Director: ABBVIE INC., AbbVie