ThyCa Comments at FDA Workshop on Therapeutic Equivalence of Levothyroxine Sodium Products

On May 23, 2005, staff of the U.S. Food and Drug Administration (FDA) met with representatives of the American Thyroid Association (ATA), American Association of Clinical Endocrinologists (AACE), and The Endocrine Society (TES).

The purpose of the joint public meeting was to discuss the FDA’s method for determining the bioequivalence of levothyroxine sodium products made by different manufacturers. Earlier, the three medical associations had issued a joint statement expressing concerns about the FDA method for determining therapeutic equivalence. The statement also advised patients “not to substitute thyroxine preparations for one another.”

Speakers from the ATA, AACE, and TES at the May meeting included Paul W. Ladenson, M.D., of Johns Hopkins University School of Medicine; James Hennessey, M.D., of Brown Medical School; E. Chester Ridgway, M.D., of the University of Colorado School of Medicine; Steven I. Sherman, M.D., of the University of Texas M.D. Anderson Cancer Center; and Leonard Wartofsky, M.D., of the Uniformed Services University of the Health Sciences.

In the public comment period during the May meeting, ThyCa Outreach Coordinator Cherry Wunderlich presented a statement from ThyCa (included below in text and PDF formats).

ATA’s web site <> has more details about the meeting and a discussion of the issue of therapeutic equivalence of different levothyroxine sodium products.

ThyCa’s web site has further information for patients on its “Know Your Pills” page, as noted in ThyCa’s statement.

Statement from ThyCa: Thyroid Cancer Survivors’ Association, Inc., to the Joint Public Meeting on Equivalence of Levothyroxine Sodium Products, 
Washington, D.C.
May 23, 2005

Thank you for this meeting. We are from ThyCa: Thyroid Cancer Survivors’ Association. We are thyroid cancer survivors and ThyCa volunteers.

As thyroid cancer patients, we have serious concerns about the matters being discussed today.

ThyCa is a national nonprofit organization advised by nationally recognized thyroid cancer specialists. ThyCa provides free education and support for patients, families, and the public. Our services include support groups, publications, workshops, and conferences. We have 5,000 to 10,000 participants in our support groups alone. Our web site receives more than 200,000 hits each month.

The need for patient support has grown rapidly, because thyroid cancer is one of the few cancers that is increasing in incidence.

We urge you to use the guidance of the leading endocrinologists on the crucial issues related to levothyroxine sodium bioequivalence. These endocrinologists are experts on thyroid issues and thyroid patient care. We patients benefit every day from their knowledge and expertise. We greatly appreciate their dedication to patient well-being.

Like other thyroid patients, we need to be sure that our blood levels of thyroid stimulating hormone (TSH) stay at the target level needed for our individual circumstances. A precise TSH level helps prevent growth or recurrence of the most common types of thyroid cancer. Dose changes prescribed by our physicians are small, usually less than 10%. For these reasons, our web site’s “Know Your Pills” page explains key points about levothyroxine and the advice of specialists to avoid changing brands without being re-tested for TSH level.

In addition, regarding bioequivalence studies needed, with over 300,000 thyroid cancer survivors, all of whom are dependent upon thyroid hormone for their survival because they have no thyroid remaining, we are confident that more than enough thyroid cancer survivors would volunteer to participate in needed bioequvalence studies.

We strongly support the analysis and recommendations of the leading endocrinologists and the American Thyroid Association, American Association of Clinical Endocrinologists, and The Endocrine Society.

As patients, we ask you to support their recommendations. Thank you again for your time and consideration.

—Gary Bloom, Board Chair
—Cherry Wunderlich, Corresponding Secretary