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CompletedNCT05712421Updated Feb 18, 2026

A Study Evaluation the Safety and Efficacy of Hormone Replacement Therapy With North Star Compared to Levothyroxine in Patients With Primary Hypothyroidism

A Phase 2 interventional study of North Star and Levothyroxine in Hypothyroidism, sponsored by Neuvosyn Laboratories, LLC. Completed at 31 sites in United States. Open to participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-02-18.

Sponsored by Neuvosyn Laboratories, LLC · Phase 2, Interventional, and Treatment

From the registry’s dates

  • Primary completion was May 2025, 1 year 5 months ago, and no results have been posted to the registry; the sponsor requested a delay in submitting them in Feb 2026.
Phase
Phase 2
Study type
Interventional
Enrollment
303
Allocation
Randomized
Ages
18 Years to 75 Years
Sex
All
01

Study summary

The North Star study is a multi-center, Phase 2, double-blind, randomized, parallel group clinical study to evaluate the safe and effective dose conversion from Levothyroxine to North Star therapy.

02

Conditions studied

  • Hypothyroidism

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03

In context

Hypothyroidism

247 studies on the registry are indexed under Hypothyroidism; 57 are open to participants now.

This study's enrollment of 303 is above the median of 78 across 128 interventional studies indexed under Hypothyroidism.

Browse Hypothyroidism studies →

Lead sponsor

Neuvosyn Laboratories, LLC is the lead sponsor of 2 studies on the registry; 1 is open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 75 Years
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  • Diagnosed with primary hypothyroidism
  • On continuous thyroid replacement therapy for at least 6 months before Study Entry
  • On a stable daily dose of LT4 for a minimum of 12 weeks prior to Screening
  • Agree to practice a method of contraception
  • Female patients not pregnant or lactating at Screening
  • Agree to practice a method of contraception of greater than 90% reliability
  • Willing to give written informed consent for the Study
  • Provide written authorization for use and disclosure of protected health information

Exclusion criteria

Exclusion Criteria:

  • Any clinical condition or previous surgery that might affect the absorption, distribution, biotransformation or excretion of North Star or levothyroxine
  • Hospitalization for a major illness within 4 weeks prior to Screening
  • Anticipated initiation or change in concomitant medications
  • Concomitant use of prohibited medications or supplements
  • Participated in another investigational new drug study within 30 days or 5 half-lives of the IMP, whichever is longer, prior to the first study drug administration.
  • For female subjects, be pregnant, nursing or planning to become pregnant during the study
05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
303 participants (actual)

Study arms

  • Experimental
    North Star

    Drug: North Star

  • Active comparator
    Levothyroxine

    Drug: Levothyroxine

Interventions

  • DrugNorth Star

    North Star

  • DrugLevothyroxine

    Levothyroxine

06

What researchers measure

Primary outcomes

  1. The ratio of the LT4 dose (mcg/day) at screening to North Star (mg/day) at the end of the treatment period required to achieve and maintain serum thyroid-stimulating hormone (TSH) levels within the normal reference range.

    Time frame: Week 30

Secondary outcomes

  1. Proportion of subjects who are euthyroid as determined by serum TSH level within the normal reference range at the end of the treatment period.

    Time frame: Week 30

07

Study locations

31 sites
  • Neuvosyn Investigational Site
    Birmingham, Alabama 35209, United States
  • Neuvosyn Investigational Site
    Canoga Park, California 91304, United States
  • Neuvosyn Investigational Site
    Greenbrae, California 94904, United States
  • Neuvosyn Investigational Site
    Toluca Lake, California 91602, United States
  • Neuvosyn Investigational Site
    Farmington, Connecticut 06030, United States
  • Neuvosyn Investigational Site
    Boca Raton, Florida 33434, United States
  • Neuvosyn Investigational Site
    Miami, Florida 33144, United States
  • Neuvosyn Investigational Site
    Miami, Florida 33145, United States
  • Neuvosyn Investigational Site
    Miami, Florida 33155, United States
  • Neuvosyn Investigational Site
    Miami, Florida 33174, United States
  • Neuvosyn Investigational Site
    Miami, Florida 33179, United States
  • Neuvosyn Investigational Site
    Sunrise, Florida 33351, United States
  • Neuvosyn Investigational Site
    Acworth, Georgia 30101, United States
  • Neuvosyn Investigational Site
    Atlanta, Georgia 30318, United States
  • Neuvosyn Investigational Site
    Columbus, Georgia 31904, United States
  • Neuvosyn Investigational Site
    Sugar Hill, Georgia 30024, United States
  • Neuvosyn Investigational Site
    Saginaw, Michigan 48602, United States
  • Neuvosyn Investigational Site
    Gladstone, Missouri 64118, United States
  • Neuvosyn Investigational Site
    Williamsville, New York 14221, United States
  • Neuvosyn Investigational Site
    Denver, North Carolina 28037, United States
  • Neuvosyn Investigational Site
    Winston-Salem, North Carolina 27103, United States
  • Neuvosyn Investigational Site
    Beavercreek, Ohio 45440, United States
  • Neuvosyn Investigational Site
    Columbus, Ohio 31904, United States
  • Neuvosyn Investigational Site
    Georgetown, Texas 78628, United States
  • Neuvosyn Investigational Site
    Houston, Texas 77040, United States
  • Neuvosyn Investigational Site
    Katy, Texas 77450, United States
  • Neuvosyn Investigational Site
    Katy, Texas 77494, United States
  • Neuvosyn Investigational Site
    Lewisville, Texas 75067, United States
  • Neuvosyn Investigational Site
    Paris, Texas 75462, United States
  • Neuvosyn Investigational Site
    Pearland, Texas 77584, United States
  • Neuvosyn Investigational Site
    Stafford, Texas 77477, United States
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Feb 18, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05712421
Lead sponsor
Neuvosyn Laboratories, LLC
Responsible party
Sponsor
First posted
Feb 3, 2023
Start date
Feb 28, 2023
Primary completion
May 5, 2025
Completion
Sep 18, 2025
Last update
Feb 18, 2026

Oversight

FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in Feb 2026. You cannot join it, but the record below documents what was studied.

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