ATA Continues Dialog With FDA on Levothyroxine Dose Precision and Bioequivalence Standards
 |
2003-2004 President Secretary Treasurer President-Elect Directors Jeffrey R. Garber, M.D. Stephanie L. Lee, M.D., Ph.D. John C. Morris, III, M.D. Rebecca S. Bahn, M.D. Donald L. St. Germain, M.D. Steven I. Sherman, M.D. Bryan R. Haugen, M.D. Sandra M. McLachlan, Ph.D. Executive Director Headquarters Office |
October 1, 2003
Janet Woodcock, M.D. Dear Dr. Woodcock: I am writing on behalf of Dr. Peter Singer, Immediate Past President of the American Thyroid Association; Dr. E. Chester Ridgway, President of the Endocrine Society; and Dr. Donald Bergman, President of the American Association of Clinical Endocrinologists. We thank you for the thoughtful manner in which you and your staff recently listened to the concerns of our societies, physician members, and patients regarding dose precision and bioequivalence standards for levothyroxine sodium formulations. We are heartened by the commitment that you made to plan and hold a workshop of sufficient depth and duration to address all of the relevant issues: bioequivalence testing baseline correction, optimal test subjects, and acceptable confidence limits; and TSH as a pharmacodynamic measure. We also support your interest in designing a crossover chronic thyroxine therapy trial with serum TSH as an outcome. We agree with you that a properly designed and executed study could address the fundamental concerns that physicians and their patients have about optimizing the safety and effectiveness of thyroxine therapy. We offer our assistance in designing, implementing, and interpreting the results of such a study. Because of the concerns that we all share regarding thyroxine dose precision and limitations in the current bioequivalence standard, we ask that 1) FDA suspend approval of new formulations until these matters are resolved, and 2) FDA not make a final decision regarding equivalence testing until it has received further input from experts at the workshop that you proposed. As you requested, we will send to you a draft agenda and list of potential contributors to the workshop program that you have proposed. Although I am no longer Secretary of the American Thyroid Association, I have become president-elect and our new president, Dr. Clark Sawin, has asked me to remain the primary point of contact between the three societies and FDA. We look forward to hearing from you. Sincerely,
PWL:sr |
See related articles on Bioequivalence of Levothyroxine
AMERICAN THYROID ASSOCIATION® , ATA® , THYROID® , CLINICAL THYROIDOLOGY® , and the distinctive circular logo are registered in the U.S. Patent and Trademark Office as trademarks of the American Thyroid Association® , Inc.