Long-Term Safety Follow-up Study of Cysteamine Bitartrate Delayed-release Capsules (RP103)

Cystinosis is an inherited disease that if untreated, results in kidney failure as early as the first decade of life. The current marketed therapy is Cystagon® (cysteamine bitartrate immediate release) which must be taken every six hours for the rest of the patient's life to prevent complications of cystinosis. Cysteamine bitartrate delayed-release capsules (RP103) is a formulation of cysteamine bitartrate that is being studied to see if it can be given less frequently, once every 12 hours, and have similar results to four times a day Cystagon®.

This is a long-term, open-label, study to determine the safety and tolerability of twice a day treatment with cysteamine bitartrate delayed-release capsules (RP103). It will involve 6-9 monthly clinic visits followed by quarterly clinic visits for the duration of the study and home use of cysteamine bitartrate delayed-release capsules. Initially, enrollment was open to those patients who had completed the previous Phase 3 Study (RP103-03, NCT01000961). Subsequently enrollment in Study RP103-04 was opened to additional participants, including children aged 1 to 6 years and renal transplant recipients, who had previously been on a stable dose of Cystagon® for at least 21 days. Study with completed results acquired from Horizon in 2024.