Summary
Trial Background
While levothyroxine (LT4) is the most common drug prescribed in the UK for an underactive thyroid gland, it does not improve symptoms in 10-15% of the population. Particularly those with the Thr92Ala mutation, which affects how thyroxine (T4) is converted into the active hormone triiodothyronine (T3).
The LIONNs-D2 trial, supported by the Medical Research Council (MRC) (grant number MR/X013170/1), aims to provide proof that a slow release T3 preparation and LT4 taken together can improve symptoms and quality of life in patients with the Thr92Ala mutation. This mutation affects the enzyme deiodinase 2 or “D2” that converts T4 to T3.
Patients who normally take thyroxine will be randomly assigned to one of two groups:
- GROUP 1 takes a combination of T4, a blank capsule and slow release T3 preparation (intervention) for the first 24 weeks of the trial, and then switches to T4 and placebo (control) for the remaining 24 weeks of the trial.
- GROUP 2 takes T4 and placebo (control) for the first 24 weeks of the trial, and then switches to a combination of T4, blank capsule and slow release T3 preparation (intervention) for the remaining 24 weeks of the trial.
Patients will not be told which group they are in and will be given tablets that look identical during the trial.
Patients will be asked to complete a questionnaire to measure thyroid related quality of life called the ThyPro questionnaire, at the start, middle and end of the trial. We will also measure other effects of the thyroid hormone including body composition, body weight and metabolic rate to compare the two treatments.
Participants will be recruited from the GenThyr cohort based at Cwm Taf Morgannwg University Health Board and run by Professor Onyebuchi Okosieme. GenThyr study participants who have been identified as having the Thr92Ala mutation and have agreed to be contacted about future research will be invited to participate in the trial. For this trial we will not be recruiting from outside the GenThyr cohort, but future studies may expand beyond South Wales once we know if slow release T3 preparation benefits patients.
Contact Details
Trial Manager / Lead Contact: Dr Kym Carter
Phone: 01792 606372
Email: k.carter@swansea.ac.uk