Use of Cysteamine in the Treatment of Cystinosis

Patients with nephropathic cystinosis have been treated with the cystine-depleting agent cysteamine since 1978. This therapy prevents or delays renal deterioration, improves growth, and depletes parenchymal tissues of cystine. Based largely upon data produced through this protocol, the Food and Drug Administration approved cysteamine bitartrate for use in cystinosis patients on August 15, 1994. Cysteamine is available as CystagonR through Mylan Pharmaceuticals in 50 mg and 150 mg capsules and as ProcysbiR in 75 mg capsules. By virtue of the current protocol, patients are admitted to the NIH Clinical Center for investigations every two years, except for cases of great interest or urgency. On each 1-3 day admission, a battery of tests is performed and the adequacy of cystine depletion by cysteamine is monitored. This protocol demonstrates the course of cystinosis patients treated with cysteamine, describes new complications of the disorder in poorly treated adults, and maintains NHGRI expertise in the field. Its monitoring and followup of patients over the course of 3 decades represents an invaluable contribution to our understanding of the natural history of this rare disease.

• INCLUSION CRITERIA:

Diagnosis of cystinosis, whether classical or one of the variants with later onset or no renal complications.

Patients will be diagnosed as having cystinosis based upon a leucocyte cystine content greater than 1 nmol half-cystine/mg protein (normal, less than 0.2) and a typical clinical course.

Exclusion criteria

Inability to travel to the NIH.

Age less than one week.

Nonviable neonates and neonates of uncertain viability will be excluded.