First of all, we want to thank Abbott Laboratories for conducting their correction method study.
However, there are some drawbacks with this particular study design. The use of 400 and 450 microgram doses yielded thyroxine concentrations that were closer to baseline. This is problematic because it prevents an accurate evaluation of the true differences that exist between the two doses and this is likely due to some sort of baseline interference. That's why the agency has recommended in the guidance and continues to recommend that doses of 600 micrograms or greater are used.
Also the checkbox slide that compared the different evaluation methods clearly shows why TSH on its own is inappropriate. The point estimate was detecting a 24 percent difference when in actuality there was only a 12.5 percent real difference between the products.
Now on to the bioequivalence design. This is the current study protocol that we're recommending to sponsors seeking A-B ratings. A single-dose, two-way crossover study in which healthy subjects will receive 600 micrograms of both test and reference product. Pharmacokinetic analysis will be conducted using total