Phase 3 Study of Cysteamine Bitartrate Delayed-release (RP103) Compared to Cystagon® in Patients With Cystinosis

Inclusion Criteria:

• Male and female subjects must have nephropathic cystinosis.

• Subjects must be on a stable dose of Cystagon® sufficient to maintain their whiteblood cell (WBC) cystine level at ≤ 1.0 nmol/half-cystine/mg protein.

• Subjects must be able to swallow their typically administered Cystagon® capsule withthe capsule intact.

• Within the last 6 months, no clinically significant change in liver function [i.e.,ALT, AST, total bilirubin] and renal function [i.e., estimated GFR] at Screening asdetermined by the Investigator.

• Subjects with an estimated GFR (corrected for body surface area) > 30 mL/min/1.73m2.

• Sexually active female subjects of childbearing potential (i.e., not surgicallysterile [tubal ligation, hysterectomy, or bilateral oophorectomy] or at least 2years naturally postmenopausal) must agree to utilize the same acceptable form ofcontraception from Screening through completion of the study.

• Subjects must be willing and able to comply with the study restrictions andrequirements.

• Subjects or their or their parent or guardian must provide written informed consentand assent (where applicable) prior to participation in the study.

Exclusion Criteria:

• Subject's age < 6 years old or subject's weight < 21 kg.

• Subjects with a known history, currently of the following conditions or other healthissues that make it, in the opinion of the investigator, unsafe for them toparticipate: inflammatory bowel disease (if currently active) or have had priorresection of small intestine; Heart disease (e.g., myocardial infarction, heartfailure, arrhythmias or poorly controlled hypertension) 90 days prior to Screening;Active bleeding disorder 90 days prior to Screening; Malignant disease within thelast 2 years.

• Patients with a hemoglobin level < 10 g/dL at Screening or a level that, in theopinion of the investigator, makes it unsafe for the subject to participate.

• Subjects receiving any form of cysteamine medication through a gastric tube.

• Subjects who are receiving maintenance dialysis or who have had a kidney transplant.

• Subjects who are on an active kidney transplant list or who are planning to receivea kidney transplant within 3 months of Screening.

• Subjects with known hypersensitivity to cysteamine or penicillamine.

• Female subjects who are nursing, planning a pregnancy, known or suspected to bepregnant, or have a positive serum pregnancy screen.

• Subjects who have a made a blood donation within 30 days of Screening.

• Subjects who, in the opinion of the Investigator, are not able or willing to complywith the protocol.