Thyroid Hormone Replacement After Radio Iodine: Value and Efficacy

NCT06647602 | Not Yet Recruiting FDA Drug

• 2 other identifiers: 114322024-511668-10-00
• Study Type: observational
• Target: 40
• Locations: 1 country
• Sites: 2

Brief Summary

This study will be a multicentre prospective cohort study on TH-substitution after thyroid hormone withdrawal preceding radioiodine treatment.

Conditions

Differentiated Thyroid Cancer; Thyroid Cancer; Levothyroxine; Liothyronine; Thyroid Hormones

Outcome Measures

Primary Outcomes (1)

• TSH after two weeks of TH substitution

  The percentage of patients reaching target TSH (\<0.5 mU/L) after two weeks of L-T3+L-T4 substitution compared to patients with L-T4-substitution.

  Before and after 2 weeks of TH-substitution

Secondary Outcomes (5)

• TSH (mU/L)

  Before and after 1, 2, 4, 6, and 12 weeks of TH-substitution.

• Thyroglobulin (Tg; ng/mL)

  Before and after 1, 2, 4, 6, and 12 weeks of TH-substitution

• QoL in patients treated with L-T3 or L-T4

  Before and after 2, 6, and 12 weeks of TH-substitution

• Heart rate (HR; bpm)

  Before and after 6 and 12 weeks of TH-substitution

• Blood pressure (BP; mmHg)

  Before and after 6 and 12 weeks of TH-substitution

Study Arms (2)

TH-combination cohort

L-T4+L-T3 combination according to local protocol.

Drug: Cytomel (liothyronine)

Levothyroxine cohort

L-T4 monotherapy according to local protocol.

Drug: Euthyrox (levothyroxine)

Interventions

Euthyrox (levothyroxine) DRUG

Euthyrox (levothyroxine sodium tablets; L-T4) is a thyromimetic synthetic drug identical to T4. Patients will recieve levothyroxine (euthyrox) in a dose of 2 μg × kg body weight / day.

Levothyroxine cohort

Cytomel (liothyronine) DRUG

Cytomel (liothyronine sodium tablets; L-T3) is a thyromimetic synthetic drug identical to T3. The patients in this cohort recieve L-T4+L-T3 combination therapy. The L-T4 dose will be 2 μg × kg body weight / day, equal to the dose in the other interventional arm. L-T3 will be added twice daily from the first day of combination treatment, in dosages gradually decreasing from 25 ug 2/day to 5 ug 2/day over a time span of 3 weeks after which L-T3 is stopped.

TH-combination cohort

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Probability Sample

Study Population

This study will include patients with a histologically confirmed high-risk DTC, men and women aged 18-75 years. Patients have to be prepared to RAI with TH-withdrawal and treated according to the ATA guidelines.

You may qualify if:

• Histologically confirmed DTC (papillary thyroid carcinoma, follicular thyroid carcinoma, oncocytic thyroid carcinoma)
• Classified as high-risk DTC according to the ATA guidelines or, patients for whom the risk of a recurrence is estimated to be higher based on clinical features (assessed by their treating physician).
• Prepared for RAI-therapy with TH-withdrawal
• Patients must be fit to adhere to the study protocol
• Patients must be able to read and understand the Dutch language

You may not qualify if:

• Pregnancy
• Patients with comorbidities, such as severe heart failure, (poorly controlled) atrial fibrillation, of which the treating physician decides that L-T3 is unsuitable.
• Conditions or drugs interfering with thyroid hormone uptake:
• Patients with a history of atrophic gastritis
• Patients using proton-pomp inhibitors

Sponsors & Collaborators

• University Medical Center Groningen: lead
• Radboud University Medical Center: collaborator

Study Sites (2)

University Medical Center Groningen (UMCG)

Groningen, Provincie Groningen, 9700RB, Netherlands

Location

Radboud University Nijmegen

Nijmegen, Netherlands

Location

Biospecimen

Retention: SAMPLES WITH DNA

Blood samples from venapuncture

MeSH Terms

Conditions

Thyroid Neoplasms

Interventions

Thyroxine; Triiodothyronine

Condition Hierarchy (Ancestors)

Endocrine Gland Neoplasms; Neoplasms by Site; Neoplasms; Head and Neck Neoplasms; Endocrine System Diseases; Thyroid Diseases

Intervention Hierarchy (Ancestors)

Thyroid Hormones; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists; Amino Acids, Aromatic; Amino Acids, Cyclic; Amino Acids; Amino Acids, Peptides, and Proteins; Thyronines

Study Officials

• Wouter Zandee, MD/PhD

  University Medical Center Groningen

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Mirthe Links, BSc

CONTACT

+31 50 3610973; m.h.links@umcg.nl

Wouter Zandee, MD/PhD

CONTACT

+31 50 3613731; w.t.zandee@umcg.nl

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 11, 2024
• First Posted: October 18, 2024
• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): March 31, 2028
• Study Completion (Estimated): December 31, 2028
• Last Updated: February 10, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

NL (2)