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

A Randomized, Double-blind, Dose-Conversion Study to Evaluate the Safety and Efficacy of Hormone Replacement Therapy With North Star Compared to Levothyroxine in Subjects With Primary Hypothyroidism Who Are Euthyroid on Levothyroxine Replacement Therapy

Status

Completed

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05712421

Enrollment

303

Registered

2023-02-03

Start date

2023-02-28

Completion date

2025-09-18

Last updated

2026-02-18

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Hypothyroidism

Brief 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.

Interventions

DRUGNorth Star

North Star

DRUGLevothyroxine

Levothyroxine

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

18 Years to 75 Years

Healthy volunteers

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

* 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

Design outcomes

Primary

Measure	Time frame
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.	Week 30

Secondary

Measure	Time frame
Proportion of subjects who are euthyroid as determined by serum TSH level within the normal reference range at the end of the treatment period.	Week 30

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 19, 2026