Cysteamine

Cystinosis is a rare disease caused by mutations in the CTNS gene that encodes for cystinosin, a protein responsible for transporting cystine out of the cell lysosome. A defect in cystinosin function is followed by cystine accumulation throughout the body, especially the eyes and kidneys.

Several preparations of cysteamine exist for the treatment of cystinosis manifestations, some in capsule form, and others in ophthalmic solution form. In particular, cystine deposits on the eye can cause significant discomfort throughout the day and require frequent treatment with eye drops, typically every waking hour.

On August 25th 2020, the first ophthalmic solution for cystinosis requiring only 4 daily treatments was granted FDA approval. Cysteamine eye drops are a practical and effective option for those affected by ocular cystinosis. Marketed by Recordati Rare Diseases Inc., CYSTADROPS® reduce the burden of multiple frequent medications normally administered to those with cystinosis.

The bitartrate salt of cysteamine is used for the oral treatment of nephropathic cystinosis and cystinuria in adults and children ≥6 years old. The hydrochloride salt, used in eye drop preparations, is indicated for the treatment of corneal cystine crystal accumulation in patients with cystinosis.