Evaluation of the Clinical and Biological Consequences of Levothyrox® Formula Modification

Status

Terminated

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT03569800

Acronym

FORTHYROX

Enrollment

Registered

2018-06-26

Start date

2018-10-11

Completion date

2019-04-03

Last updated

2019-06-20

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

Conditions

Thyroid Disorder

Keywords

Levothyrox®, thyroid hormones, bioequivalent

Brief summary

The purpose of this study is to determine whether the recent excipient modification of Levothyrox® in France for a bioequivalent formula has clinical and biological consequence for the patients. The investigators also plan to describe the patient journey in terms of levothyroxine based drugs since this formula modification of Levothyrox®.

Detailed description

Levothyrox® is a levothyroxine based drug marketed in France in order to substitute a lack of thyroid hormones. Because of a lack of stability during time and because of wide inter-batch variability in terms of active molecule, the National Agency of Safety of Medicaments (ANSM) ask to the market authorization holder to develop a new formula without lactose. This new formula, which has been proven to be bioequivalent has been marketed since march 2017 in France. Some patients were predicted to have their thyroid function imbalance because of this modification. The purpose of the study is to analyse, on the patients treated by Levothyroxine® in how many patients this modification has clinical and biological consequences.

Interventions

OTHERself completed questionnaire

self completed questionnaire

Study design

Observational model

CASE_ONLY

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* Thyroid disorder treated by Levothyroxine * Age over 18 year old * TSH plasma level within the 12 months before formulation modification * TSH plasma level within the 6 months after formulation modification

Exclusion criteria

\- Thyroid dysfunction (hypo or hyperthyroidism) despite Levothyroxine treatment, ie TSH plasma level out of normal range within the 6 months before formula modification

Design outcomes

Primary

Measure	Time frame	Description
Number of abnormal Thyroid Stimulating Hormone (TSH) level after change of levothyrox formulation	1 day	Evaluated with a self completed questionnaire

Secondary

Measure	Time frame	Description
Number of patients treated with new formulation of levothyrox	1 day	Evaluated with a self completed questionnaire
Difference betweenTSH plasma levels before and after formulation change	1 day	Evaluated with a self completed questionnaire

Countries

France

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026