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Block-replacement Therapy During Radioiodine Therapy

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Steen Bonnema, Odense University Hospital
ClinicalTrials.gov Identifier:
NCT00150124
First received: September 6, 2005
Last updated: December 3, 2013
Last verified: December 2013
  Purpose

Background: The use of radioactive iodine (131I) therapy as the definite cure of hyperthyroidism is widespread. According to a survey on the management of Graves' disease, thirty per cent of physicians prefer to render their patients euthyroid by antithyroid drugs (ATD) prior to 131I therapy. This strategy is presumably chosen to avoid 131I induced 'thyroid storm', which, however, is rarely encountered. Several studies have consistently shown that patients who are treated with ATD prior to 131I therapy have an increased risk of treatment failure. Mostly, patients with Graves' disease have been studied, while other studies were addressed also toxic nodular goiter. Thus, it is generally accepted that ATD have 'radioprotective' properties, although this view is almost exclusively based on retrospective data and is still under debate. Indeed, this dogma was recently challenged by two randomized trials in Graves' disease, none of which showed such an adverse effect of methimazole pretreatment. It cannot be excluded that the earlier results may have been under influence of selection bias, a source of error almost unavoidable in retrospective studies. Whether ATD is radioprotective also when used in the post 131I period has also been debated. In the early period 131I therapy following a transient rise in the thyroid hormones is seen which may give rise to discomfort in some patients. The continuous use of ATD during 131I therapy, possibly in combination with levothyroxine (BRT: block-replacement therapy), leads to more stable levels of the thyroid hormones. By resuming ATD following 131I therapy, euthyroidism can usually be maintained until the destructive effect of 131I ensues. Nevertheless, many physicians prefer not to resume ATD, probably due to reports supporting that such a strategy reduces the cure rate. Parallel to the issue of ATD pretreatment, the evidence is based on retrospective studies and the ideal set-up should be reconsidered. To underscore the importance of performing randomized trials we showed recently that resumption of methimazole seven days after 131I therapy had no influence on the final outcome.

Aim:To clarify by a randomized trial whether BRT during radioiodine therapy of hyperthyroid patients influences the final outcome of this therapy, in a comparison with a regime in which methimazole as mono-therapy is discontinued 8 days before radioiodine.

Patients and Methods: Consecutive patients suffering from recurrent Graves' disease (n=50) or a toxic nodular goiter (n=50) are included. All patients are rendered euthyroid by methimazole (MMI) and randomized either to stop MMI eight days before 131I or to be set on BRT. This latter medication continues until three months after 131I. Calculation of the 131I activity (max. 600 MBq) includes an assessment of the 131I half-life and the thyroid volume. Patients are followed for one year with close monitoring of the thyroid function.


Condition Intervention Phase
Toxic Nodular Goitre
Graves' Disease
Drug: MTZ+LT4
Drug: Methimazole
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: The Influence of Continuous Block-replacement Therapy on the Effect of Radioiodine in Patients With Hyperthyroidism

Resource links provided by NLM:


Further study details as provided by Odense University Hospital:

Primary Outcome Measures:
  • Thyroid function after one year of follow-up [ Time Frame: one year ] [ Designated as safety issue: Yes ]

Secondary Outcome Measures:
  • Thyroid radioiodine 131I uptake [ Time Frame: one month ] [ Designated as safety issue: Yes ]
  • Thyroid volume after one year of follow-up [ Time Frame: one year ] [ Designated as safety issue: No ]

Enrollment: 100
Study Start Date: January 2003
Study Completion Date: March 2009
Primary Completion Date: December 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: block-replacement therapy
BRT regimen until 3 months after 131I therapy
Drug: MTZ+LT4
Active Comparator: methimazole
methimazole stopped 8 days before 131I therapy
Drug: Methimazole

  Eligibility

Ages Eligible for Study:   18 Years to 85 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Hyperthyroid patients going to be treated with radioiodine either due to recurrent Graves' disease or toxic nodular goiter.

Exclusion Criteria:

  • Age < 18 yrs.
  • Allergy to anti-thyroid drugs
  • Substernal or large (> 100ml) goiter
  • Severe endocrine ophthalmopathy
  • Pregnancy or lactation
  • Suspicion of thyroid malignancy
  • Unsafe contra-conception
  • Physical or mental condition that hinders corporation
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00150124

Locations
Denmark
Department of Endocrinology, Odense University Hospital
Odense, Funen, Denmark, 5000
Sponsors and Collaborators
Steen Bonnema
Investigators
Principal Investigator: Steen J. Bonnema, MD, PhD Odense University Hospital
  More Information

No publications provided by Odense University Hospital

Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Steen Bonnema, Consultant, phd, DMSc, Odense University Hospital
ClinicalTrials.gov Identifier: NCT00150124     History of Changes
Other Study ID Numbers: 012
Study First Received: September 6, 2005
Last Updated: December 3, 2013
Health Authority: Denmark: National Board of Health

Keywords provided by Odense University Hospital:
Radioiodine therapy
Graves' disease
toxic nodular goiter
antithyroid drugs
levothyroxine
radioprotection

Additional relevant MeSH terms:
Goiter, Nodular
Graves Disease
Hyperthyroidism
Autoimmune Diseases
Endocrine System Diseases
Exophthalmos
Eye Diseases
Goiter
Immune System Diseases
Orbital Diseases
Thyroid Diseases

ClinicalTrials.gov processed this record on November 27, 2014