Bioequivalence of Two Levothyroxine Tablet Formulations in Healthy Indian Volunteers

Hypothyroidism Clinical Trial

Official title: Bioequivalence of Two Levothyroxine Tablet Formulations in Healthy Indian Volunteers: A Single-dose, Randomized, Open-label, Crossover Study

Status Completed

Clinical Trial Summary

GSK markets a drug called levothyroxine or T4 that is used to treat patients with hypothyroidism. Till date, the active drug substance or active pharmaceutical ingredient (API) for levothyroxine tablets marketed in India has been obtained from a particular source. GSK India proposes to change the source of the API from the existing source to a new source. Some patients may experience a change in clinical effect when switched from one formulation to another. Therefore this study is being done to understand whether a change in API in levothyroxine tablet has any impact on the clinical effect of the drug.

The purpose of this study is to:

See how quickly the levothyroxine tablet from the new source (single dose of 600mcg) enters the bloodstream, is distributed in the body, broken down and removed compared to the levothyroxine tablet from the existing source (single dose of 600mcg).

Study the effect of single 600mcg doses of levothyroxine tablet from new source and levothyroxine tablet from existing source on TSH level in the blood.

Study the safety and side effects of single 600mcg doses of levothyroxine tablet from new source and levothyroxine tablet from existing source.

Clinical Trial Description

Levothyroxine (T4) is used to treat patients with hypothyroidism and may often result in lifelong therapy. Its physiologically active metabolite is tri-iodothyronine (T3). Levothyroxine is also endogenously produced in the body. Since small changes in levothyroxine administration (e.g. change in brand or formulation) can cause significant changes in serum thyroid stimulating hormone (TSH) concentrations, precise and accurate TSH control is critical to avoid potential adverse iatrogenic effects. Till date, the active pharmaceutical ingredient (API) for levothyroxine tablets marketed in India has been sourced from company 1. GSK India proposes to change the source of the API from the existing source (company 1) to to new source (company 2). In view of this change in the source of API, it is essential to determine whether it has any impact on drug product performance based on pharmacokinetic (PK) measures of total serum T4 and total serum T3 of the to-be-marketed formulation of levothyroxine (test formulation from company 2, Treatment A) relative to the formulation currently in the market (reference formulation from company 1, Treatment B).

This will be a single-center, open-label, two-period, two-treatment, two-sequence, randomized, single-dose, crossover study. 26 healthy adult males will be randomized to receive a single dose (6 x 100mcg tablets = 600mcg) of the test formulation of levothyroxine and reference formulation of levothyroxine separately in each treatment period. There will be two treatment sequences (AB, BA) and a 35 day washout between the two treatment periods.

The study will be conducted at BA/BE facility after approval from an independent ethics committee. Subjects will have a screening visit within 21 days prior to the first dose of study drug, two treatment periods with each containing a single dose of study drug, followed by 48 hours of serial PK sample collection. Subjects will check out of the unit on Day 3 (at 7am) after collection of the 48 hour PK sample. The subject will be instructed to return for the next treatment period or for the final follow-up visit, as appropriate. The final follow-up visit will occur 35 days after the last dose of study drug. Subjects will be assigned to each of the two treatments randomly as per the randomization schedule. ;

Related Conditions & MeSH terms

• Hypothyroidism

• NCT number: NCT01536678
• Study type: Interventional
• Source: GlaxoSmithKline
• Status: Completed
• Phase: Phase 4
• Start date: January 2012
• Completion date: April 2012