Formulation of Levothyroxine plus slow-release Liothyronine preparation for treatment of hypothyroidism (Clinical trial Phase 2& 3)

Phase 3: To assess and compare the efficacy of treatment with LT4+SR-T3 with that of LT4 monotherapy.

The parallel randomized double-blind controlled clinical trial

Setting: Tehran Thyroid Study (TTS). At the first visit, a fasting blood sample will be obtained to measure serum TSH, TT3, TT4, FT4, FT3, FBS, lipid profile, insulin, HbA1C, HOMA-IR, SHBG, Enolase, LDH and CK, Ferritin, and metabolomics. Assessment of demographic data, quality of life, symptoms of thyroid function, and physical examination will be done. Body composition will be measured. The specified treatment will be given to both groups for 48 weeks. All tablets will be distributed in similar packages and the same size and color to ensure double-blinded design. Participants will be evaluated at baseline and 3 follow-ups at first, six, and 12 months after the start-up. All blood parameters and questionnaires will be filled out at baseline and 6 and 12 months after start-up. Also, the polymorphism related to deiodinase will be measured and compared between responders and non-responders.

Inclusion: Patients≥20y with hypothyroidism who attain euthyroidism under LT4 monotherapy. Exclusion: Pregnancy, end organ failure,cancer,taking methimazole,PTU,Tamoxifen, estrogen,progesterone and corticosteroids.

Phase 3: 1. LT4+SR-T3 2. LT4 monotherapy

1. T3/T4 ratio,TSH,T4,T3, FT4,FT3 2. Clinical signs and symptoms of hypothyroidism 3. Quality of life 4. Patient preference 5. SerumLipid profile 6. FBS,HbA1C,HOMA-IR 7. SHBG 8. Enolase,LDH,CK 9. C-telopeptide or N-telopeptide 10. Ferritin 11. heart rate,BP 12. Metabolomics 13. Genetic polymorphism 14.Body composition

Update 2: Reasons for the update The results of the clinical trial phase 2 were presented in a publication* and made us update the protocol of phase 3 in a few parts which are as follows: 1. We found that we should increase the ratio of SR-T3 to LT4 in the combination therapy. We also formulated SR-T3 in isolated tablets and not in one tablet/ capsule preparation due to the complexity of drug formulation and mixing a slow-release and normal-release product. In the new version, we consider treating hypothyroid patients with 75 µg lt4 and 15 µg sr-t3 and adjust the dosage based on the patient's weight. 2. We deleted the normal control group, there for our trial groups consist of one control group (LT4 monotherapy) and a trial group ( receiving 75 µg LT4 and 15 µg SR-T3) 3. We decided to measure all outcomes in 6 and 12 months after starting the trial instead of only at the end of the trial. 4. We also decided to measure body composition as another outcome of the trial. *Mehran L, Amouzegar A, Foroutan SM, Masoumi S, Tohidi M, Abdi H, Aghaei A, Saghafinia AE, Azizi F. Pharmacodynamic and pharmacokinetic properties of the combined preparation of levothyroxine plus sustained- release liothyronine; a randomized controlled clinical trial. BMC Endocr Disord. 2023 Aug 28;23(1):182. UPDATE 1 The phase 3 clinical trial had been approved previously by IRCT, but due to Covid-19 epidemic crisis, the trial was postponed. At the present time, we are ready to conduct the trial, however, based on the recently published Consensus Statements to guide development of best-designed future clinical trials of LT4+LT3 combination therapy by the American Thyroid Association (ATA), British Thyroid Association (BTA), and European Thyroid Association (ETA), we are going to make some changes in the protocol and update the previous trial in some parts including the extension of follow- up period up to 12 months, adding new outcomes (bone markers of C-telopeptide/N-telopeptide, Resting energy expenditure) and replacing the primary outcome to quality of life based on the suggestions made by the Consensus Statements1. Also, we added the complementary phase 2 clinical trial in a limited number of hypothyroid patients to evaluate the effectiveness and safety of monotherapy with our SR-T3 product. In the complementary phase 2 clinical trial we will select 30 patients with hypothyroidism (serum TSH>30 mU/L). These patients will be randomized into three groups receiving 1.6 μg/kg L-T4, equivalent doses of SRT3 and L-T3 of 0.55 μg/kg for 4 weeks and serum fT4, T3 and TSH will be measured weekly up to 4 weeks. This study is preliminary study to the previous approved clinical trial and the National Research Council of the Islamic Republic of Iran and the Human Research Review Committee of the Endocrine Research Center, Shahid Beheshti University, Tehran, Iran approved the complementary phase 2 protocol (IR.SBMU.ENDOCRINE.REC.1402.031). Trial participants will sign informed consent forms at baseline, and their personal information will remain strictly confidential. 1. Jonklaas J, Bianco AC, Cappola AR, Celi FS, Fliers E, Heuer H, McAninch EA, Moeller LC, Nygaard B, Sawka AM, Watt T, Dayan CM. Evidence-Based Use of Levothyroxine/Liothyronine Combinations in Treating Hypothyroidism: A Consensus Document. Thyroid. 2021 Feb;31(2):156-182.

Phase 3: Patients will be allocated to intervention and control groups using simple stratified randomization. 1. The groups with a daily intake of LT4+SR-T3 (Intervention Group) 2. The groups with LT4 mono-therapy (Control group) Participants will be randomized with equal probability (1:1) to receive one of the two treatments. As the size of each group is predicted to be 50 , the allocation sequence is generated with sample randomization and stratification by gender. The sequences will be generated by the software and in Excel format. The patients sequentially entered to study based on this random sequence. Phase 2: After simple randomization, participants will be assigned to a pre-breakfast regimen of SRT3, L-T3, or L-T4 for 4 weeks. The dose of L-T4 is 1.6 μg/kg. This dosage will be adjusted to achieve 1:5 ratio of SR-T3 to LT4 in combination therapy. Patients will be recalled to the endocrine clinic for weekly follow-up visits and blood sampling.

After proper implementation of randomization, the subjects will be assigned to the groups using allocation concealment which helps to keep clinicians, participants and investigators unaware of upcoming assignments. The standard methods of ensuring allocation concealment will be sequentially numbered or coded opaque containers. For single-center clinical trials such as the current trial, we will identify a staff member not involved with the trial who can keep the randomization list. This staff will be instructed to keep the list private and to only reveal a treatment allocation after receiving information demonstrating that the patient is eligible and has consented to the trial. Both the subjects and the investigators will be kept from knowing who will be assigned to which treatment (double-blind) to fulfill this both groups will receive tablets that are identical in physical appearance, taste, and smell. The patients in the control group will receive Placebo instead of SR-T3.

These data are belonged to Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran