 - Has thyroid-stimulating hormone TSH results within normal laboratory limits at screening for all participants not receiving thyroid hormone replacement therapy. For participants on thyroid hormone replacement therapy, the thyroid hormone dose must have been stable for at least 4 weeks before screening, and serum TSH level must be within the central laboratory reference range. A serum TSH level below the lower limit of the normal range but not undetectable in participants treated with thyroid hormone may be allowed if there is no anticipated need for a change in thyroid hormone dose during the trial. 