Archived Article – The Thyroid Society (1998 – 2003)
Re: Thyrogen Advisory Panel, NDA 20-898
Dear Ms. Reedy:
I am writing in reference to the notice published in the Federal Register on 26 March 1998 announcing the Endocrinologic and Metabolic Drugs Advisory Committee meeting on 15 May 1998 to discuss the Thyrogen NDA (20-898), submitted by the Genzyme Corporation.
This letter is being submitted as documentation of my views and comments that I would like to be made known to the panel, and to be read during the public forum at the start of the meeting.
In the United States, fewer than 200,000 patients are alive with a diagnosis of differentiated thyroid carcinoma. Most of these persons will live long enough to die from something other than their thyroid malignancy, and in part this is due to the efficacy of scanning and therapy with radioiodine for this disease. However, for decades, the standard preparative regimen for patients to undergo these scans included thyroid hormone withdrawal, with all the attendant symptomatic complications of severe hypothyroidism. For example, as a thyroid specialist in Houston, I have seen many patients turning off their air conditioning during the summer months due to the severe cold intolerance, only to add discomfort and misery to the lives of their spouses and other residential inhabitants. More seriously, individuals often in their most productive years of life become markedly debilitated, often unable to work or function intelligibly in their daily routines, all related to their iatrogenic hypothyroidism. Deaths have occurred in these individuals, attributed to impaired motor skills such as automobile driving. Patients have experienced symptomatic disease progression due to the prolonged elevation of TSH levels associated with thyroid hormone withdrawal, particularly those with critically located metastatic lesions in the spine or central nervous system. Finally, the inconvenience of planning and appropriately carrying out thyroid hormone withdrawal leads to an unacceptable frequency of patients not discontinuing their hormone medications at the correct time. For all these reasons, there is a large cohort of patients who should probably undergo radioiodine scanning who do not, because the individuals are either unable or unwilling to undergo thyroid hormone withdrawal.
In 1998, there are no alternative approaches to inducing hypothyroidism for performing radioiodine scanning. Thus, as the Medical Director of the Thyroid Society, I would strongly urge the FDA to provide favorable review and approve the NDA for Thyrogen. For thousands of patients who will be diagnosed in the next year, the appearance of this drug will mean that they will be less likely to ever have to undergo unnecessary thyroid hormone withdrawal. For the tens of thousands of previously treated patients, the availability of Thyrogen will likely lead to increased detection of residual or metastatic thyroid cancer, given improved adherence with recommended scanning. Most importantly, for the subgroup of patients whose thyroid cancer or comorbid conditions does not permit thyroid hormone therapy to be withdrawn safely, Thyrogen will be an essential addition to their treatment program.
The Thyroid Society for Education and Research exists to advance the health of patients with all types of thyroid disease, including those individuals with the orphan disease of differentiated thyroid cancer. For the benefit of these patients, I again urge the FDA to approve the Thyrogen NDA. I look forward to the outcome of the FDA Advisory Panel hearing of 15 May 1998, and to the eventual availability of Thyrogen for our patients.
Steven I. Sherman, M.D.
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