Withdrawal of Tiratricol Treatment in Males with Monocarboxylate Transporter 8 Deficiency (MCT8 Deficiency): A Double-blind, Randomized, Placebo-controlled Study

Phase 3

• Conditions: Allan-Herndon-Dudley syndrome; MCT8 deficiency; 10014699; 10043739; 10029317

• Registration Number: NL-OMON53686
• Lead Sponsor: Rare Thyroid Therapeutics

Brief Summary

Not available

Detailed Description

Not available

Study Timeline

• Last Update Posted: 19 August 2024

Recruitment & Eligibility

• Status: Pending
• Sex: Not specified
• Target Recruitment: 5

Inclusion Criteria

1. Male participants diagnosed with a pathogenic mutation in the MCT8 gene,
confirmed with a genetic test.
2. Serum total T3 concentration above the ULN of the age-specific normal range:
a) at the time of diagnosis (or the closest sample taken prior to first ever
treatment with tiratricol) for participants who are currently treated with
tiratricol
b) in the Screening Visit sample, or most recent standard of care sample prior
to screening, for participants who have never received and/or currently not
receiving tiratricol.
3. Participants will be aged 4 years or older at the time of randomization.
Participants entering screening who are <4 years of age but expected to be aged
4 years at randomization should be discussed with the medical monitor.
4. Signed and dated informed consent form from the parents or legal guardian.

Exclusion Criteria

1. Major illness or recent major surgery unrelated to MCT8 deficiency (in the
principal investigator*s judgement), defined as:
• Conditions requiring repeated hospitalizations that are likely to
confound ability to participate in the trial.
• Major illness in the 3 months prior to the Screening Visit that is likely
to confound the ability of the participant to participate fully within
the trial and/or confound the assessment of serum total T3 and/or
safety.
• Major surgery within the 3 months prior to the Screening Visit or
planned to take place during the study, including but not limited to
major abdominal/thoracic/neurosurgical procedures.
• Major/minor abdominal and/or maxillofacial surgery that may inhibit
the administration and/or absorption of study drug.
2. Body weight <10 kg at the Screening Visit.
3. Patients who are participating, or intend to participate, in other
therapeutic
and/or interventional clinical studies during the study period.
4. History of allergic reactions to components of tiratricol or any excipients
in
the investigational product (IP).
5. Participants with any contra-indication for treatment with tiratricol or any
excipients in the IP.
6. Participants using other T3 analogues, levothyroxine, or propylthiouracil.

In addition to these eligibility criteria, participants must meet further
criteria at the time
of randomization to enter the Randomized Treatment Period.
Randomization criteria:
1. Confirmation that the *Stable Dose Criterion* has been met.
2. Absence of any new or exacerbated medical or surgical condition that fulfils
Exclusion criterion #1.
3. Confirmation that participant is at least 4 years of age at the time of
randomization.

Study & Design

• Study Type: Interventional
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
<p>Proportion of participants who meet the rescue criterion (serum total<br /><br>T3 > ULN) from samples obtained during the 30-day double-blind<br /><br>Randomized Treatment Period</p><br>