Plain English Summary
Background and study aims
Thyrotoxicosis (an overactive thyroid) arises when there is too much thyroid hormone in the body. It is an uncommon disorder in childhood and adolescence. Most patients with thyrotoxicosis have Graves disease, where antibodies 'switch on' the thyroid gland and causes it to produce too much thyroid hormone. Many general paediatricians have experience of managing patients with thyrotoxicosis but national guidelines to assist in patient care have not been produced to date. There is no ideal therapy for thyrotoxicosis in children and adolescents. The three treatment types for thyrotoxicosis - anti-thyroid drugs, surgery and radioiodine - all have significant disadvantages. Particular considerations when managing young people include:
1. Low remission rates following a course of anti-thyroid drug therapy - when the anti-thyroid drug is stopped the condition usually returns
2. Concerns about the morbidity associated with thyroidectomy - thyroid surgery leaves a scar, can cause voice change and can leave patients dependent on Vitamin D tablets to prevent low calcium levels
3. Shortage of data on the long-term safety of radioiodine - radioiodine involves radiation which will be associated with a small increase in cancer risk
Children and adolescents with autoimmune thyrotoxicosis in the United Kingdom are usually treated with anti-thyroid drugs, from diagnosis for 1 to 4 years. Treatment is then stopped and patients whose condition deteriorates return to anti-thyroid drugs or are treated with surgery or radioiodine. Lifelong thyroid hormone replacement will be required if the thyroid gland is removed by surgery or eradicated by radioiodine. The excess thyroid hormone in thyrotoxicosis can prevent people from concentrating properly and can also affect the health of the heart and bones. Keeping thyroid hormone levels normal is therefore very important. There are two possible approaches when treating patients with anti-thyroid drug (almost always carbimazole):
1. Combined therapy - otherwise known as 'block and replace', where thyroid hormone production is prevented by anti-thyroid drug and thyroxine is then added in a replacement dose
2. Adaptive therapy - otherwise known as 'dose titration', where the dose of the anti-thyroid drug is adjusted so that hormone production is normalised
Both strategies are used in adults but it is unclear which of these approaches is the most appropriate in the young person. Potential advantages of the combined therapy include improved stability with fewer episodes of hyper- or hypo-thyroidism, a reduced number of blood tests and visits to hospital, and improved remission rates following a larger anti-thyroid drug dose. Potential advantages of the adaptive therapy include fewer side effects with a lower anti-thyroid drug dose, and improved compliance on one rather than two medications. A study is therefore proposed which aims to establish which treatment - block and replace or dose titration - is the most appropriate medical therapy during childhood and adolescence.
Who can participate?
Patients with thyrotoxicosis aged between 2 and 16 at the time of diagnosis.
What does the study involve?
The study involved subjects undergoing standard medical therapy for thyrotoxicosis using an anti-thyroid drug. Patients were randomly allocated to either the 'block and replace' or the 'dose titration' approach for a period of 3 years.
What are the possible benefits and risks of participating?
Risks to participants are low, as this study is looking at treatments already used in standard practice.
Where is the study run from?
Royal Victoria Infirmary (UK).
When is the study starting and how long is it expected to run for?
The study ran from January 2005 to January 2013.
Who is funding the study?
Newcastle upon Tyne NHS Foundation Trust (UK).
Who is the main contact?
Dr Tim Cheetham (Chief Investigator)
tim.cheetham@nuth.nhs.uk
Trial website
Contact information
Type
Scientific
Primary contact
Dr Tim Cheetham
ORCID ID
Contact details
c/o Old Childrens Outpatients
Royal Victoria Infirmary
Queen Victoria Road
Newcastle upon Tyne
NE1 4LP
United Kingdom
-
tim.cheetham@nuth.nhs.uk
Additional identifiers
EudraCT number
2011-001238-40
ClinicalTrials.gov number
NCT01436994
Protocol/serial number
2759
Study information
Scientific title
A randomised study of two anti-thyroid drug treatment regimens in young people with thyrotoxicosis
Acronym
Study hypothesis
Current hypothesis as of 06/10/2014:
'Block and replace' vs 'dose titration' anti-thyroid drug treatment: is there any difference between the two regimens in terms of biochemical stability.
Previous hypothesis:
Block & replace vs titration - any/no difference between efficacy, side effects or remission rates.
On 06/10/2014 the following changes were made to the trial record:
1. The anticipated end date was changed from 01/01/2013 to 01/11/2015.
2. The target number of participants was changed from 160 to 128.
3. 'The British Thyroid Foundation & The Child Growth Foundation' was added to the sources of funding field.
Ethics approval
Thames Valley Multi-centre Research Ethics Committee (committee name changed to Berkshire Valley REC), 14/07/2004, ref: 04/12/015
Study design
Two-arm randomised controlled trial
Primary study design
Interventional
Secondary study design
Randomised controlled trial
Trial setting
Hospitals
Trial type
Treatment
Patient information sheet
Condition
Thyrotoxicosis in children, endocrinology
Intervention
Current interventions as of 06/10/2014:
1. This is a multi-centre phase III randomised controlled trial of two standard treatments comparing outcomes for the block and replace regimen versus dose titration regimen in patients with thyrotoxicosis
2. The target recruitment is for 128 participants
3. Participants will be randomised, on a 1:1 ratio, as follows:
3.1. Block and replace regimen: [carbimazole (or propylthiouracil) plus thyroxine]
3.2. Titration regimen: carbimazole (or propylthiouracil)
4. Block and replace regimen:
4.1. The objective of treatment is to maintain free thyroxine concentrations in the normal laboratory range (mean -2SD < FreeT4 > mean + 2SD) with a TSH that is also within the normal laboratory range (neither elevated nor suppressed)
4.2. Carbimazole is commenced in a dose of 0.75 mg/kg/day The intention is to completely prevent endogenous thyroxine production
4.3. Thyroxine is then added in a low replacement dose as the thyroid hormone levels fall into the lower half of the laboratory normal range
5. Dose titration regimen:
5.1. The objective of treatment is to maintain free thyroxine concentrations in the normal laboratory range (mean -2SD < FreeT4 > mean + 2SD) with a TSH that is also within the normal laboratory range (neither elevated or suppressed)
5.2. Carbimazole is commenced in a dose of 0.75 mg/kg/day until thyroid hormone levels fall into the local laboratory normal range
5.3. The dose is then reduced to 0.25 mg/kg/day with the intention of maintaining a euthyroid state as reflected by a free thyroxine and TSH within the normal range
Previous interventions:
1. This is a multi-centre phase III randomised controlled trial of two standard treatments comparing outcomes for the block and replace regimen versus dose titration regimen in patients with thyrotoxicosis
2. The target recruitment is for 160 participants
3. Participants will be randomised, on a 1:1 ratio, as follows:
3.1. Block and replace regimen: [carbimazole (or propylthiouracil) plus thyroxine]
3.2. Titration regimen: carbimazole (or propylthiouracil)
4. Block and replace regimen:
4.1. The primary objective of treatment is to maintain free thyroxine concentrations in the normal laboratory range (mean -2SD < FreeT4 > mean + 2SD) with a TSH that is also within the normal laboratory range (neither elevated nor suppressed)
4.2. Carbimazole is commenced in a dose of 0.75 mg/kg/day The intention is to completely prevent endogenous thyroxine production
4.3. Thyroxine is then added in a low replacement dose as the thyroid hormone levels fall into the lower half of the laboratory normal range
5. Dose titration regimen:
5.1. The primary objective of treatment is to maintain free thyroxine concentrations in the normal laboratory range (mean -2SD < FreeT4 > mean + 2SD) with a TSH that is also within the normal laboratory range (neither elevated or suppressed)
5.2. Carbimazole is commenced in a dose of 0.75 mg/kg/day until thyroid hormone levels fall into the local laboratory normal range
5.3. The dose is then reduced to 0.25 mg/kg/day with the intention of maintaining a euthyroid state as reflected by a free thyroxine and TSH within the normal range
Intervention type
Drug
Phase
Not Applicable
Drug names
Carbimazole, propylthiouracil, thyroxine
Primary outcome measures
Current primary outcome measures as of 06/10/2014:
Biochemical control as reflected by blood thyroid stimulating hormone (TSH) levels. The standard deviation of the proportion of TSH measurements above or below the laboratory normal range on block and replace and dose titration regimens (n=12) is approximately 0.2. A clinically important difference in means between the two study groups is 0.1. 128 patients (two groups of 64 patients) required to detect a mean difference in control of 0.1 with 80% power at the 5% level. This primary outcome measure will be assessed at year 3 when subjects will have received anti-thyroid drug for 3 years.
Previous primary outcome measures:
We have undertaken a power estimation based on the assumption that a 20% absolute improvement in remission by 4 years would establish an indisputable clinically significant benefit of one regimen over the other. To gain 80% power with an assumption of 5% loss to follow up, we calculate that we would have to allocate 80 subjects to each treatment group
Secondary outcome measures
Current secondary outcome measures as of 06/10/2014:
Additional measures of biochemical control:
1. A comparison of the mean and variability (SD) of TSH and thyroid hormone concentrations in the two treatment groups
2. Remission rates as defined by patients who are biochemically euthyroid at the end of the 4-year study period
3. The frequency of adverse events on the two treatment regimens
Previous secondary outcome measures:
We have also undertaken a power calculation so that we can be confident that a key secondary outcome measure (measure 2) will also be addressed. The standard deviation of the proportion of TSH measurements above or below the laboratory normal range on block and replace and dose titration regimens (n=12) is approximately 0.2 (unpublished data from Newcastle-upon-Tyne and Glasgow). These outcome measures will be assessed at year 3, year 4 and year 6 using biochemistry results to show the stability of the patients thyroid function
Overall trial start date
10/01/2005
Overall trial end date
01/11/2015
Reason abandoned
Eligibility
Participant inclusion criteria
1. All patients with thyrotoxicosis aged between 2 and 16 years at the time of diagnosis
2. Thyrotoxicosis will be diagnosed by the paediatrician on the basis of the clinical picture and the biochemistry [suppressed thyroid stimulating hormone (TSH) with high thyroid hormone levels]
3. Child must consent/assent or consent via parent/guardian must be gained prior to any study-specific procedures
Participant type
Patient
Age group
Child
Gender
Both
Target number of participants
128
Participant exclusion criteria
1. Known toxic adenoma/toxic hyperplasia [germline activating thyroid-stimulating hormone receptor (TSHR) mutation]
2. McCune Albright Syndrome
3. Previous episodes of thyrotoxicosis
4. Known allergic response to any of the study medication or ingredients as per Summary of Product Characteristics (SmPC)
5. Previous participation in this study
Recruitment start date
12/01/2005
Recruitment end date
29/11/2011
Locations
Countries of recruitment
United Kingdom
Trial participating centre
c/o Old Childrens Outpatients
Newcastle upon Tyne
NE1 4LP
United Kingdom
Sponsor information
Organisation
The Newcastle upon Tyne NHS Foundation Trust (UK)
Sponsor details
Joint Research Office
Level 6
Leazes Wing
Royal Victoria Infirmary
Queen Victoria Road
Newcastle upon Tyne
NE1 4LP
United Kingdom
Sponsor type
Hospital/treatment centre
Website
Funders
Funder type
Hospital/treatment centre
Funder name
Newcastle upon Tyne NHS Foundation Trust (UK)
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Funder name
The British Thyroid Foundation & The Child Growth Foundation (UK)
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting
Publication summary