long-term safety follow-up study of cysteamine bitartrate delayed-release capsules (rp103)

Conditions: Cystinosis

Summary: 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.

Eligibility criteria:
inclusion criteria: * male and female subjects must have completed the last visit of study rp103-03 and be willing to continue with rp103 treatment. or for patients who did not complete the rp103-03 study: * male and female subjects must have cystinosis. * subjects must be on a stable dose of cystagon® at least 21 days prior to screening. * within the last 6 months, no clinically significant change from normal in liver function tests (i.e., alanine aminotransferase \[alt\], aspartate aminotransferase \[ast\], total bilirubin) and renal function (i.e., estimated glomerular filtration rate \[egfr\]) at screening as determined by the investigator. * subjects with an egfr corrected for body surface area \> 30 ml/min/1.73m². * sexually active female subjects of childbearing potential (i.e., not surgically sterile \[tubal ligation, hysterectomy, or bilateral oophorectomy\] or at least 2 years naturally postmenopausal) must agree to utilize the same acceptable form of contraception from screening through completion of the study. * subjects must be willing and able to comply with the study restrictions and requirements. * subjects or their parent or guardian must provide written informed consent and assent (where applicable) prior to participation in the study. exclusion criteria: * patients enrolled in the previous study rp103-03 who did not complete their last scheduled study visit or who do not wish to continue on treatment with rp103. and for patients who did not complete the rp103-03 study: * subjects less than 1 year old * subjects with a known history, currently of the following conditions or other health issues that make it, in the opinion of the investigator, unsafe for them to participate: inflammatory bowel disease (if currently active) or have had prior resection of small intestine; heart disease (e.g., myocardial infarction, heart failure, unstable arrhythmias or poorly controlled hypertension) 90 days prior to screening; active bleeding disorder 90 days prior to screening; malignant disease within the last 2 years. * patients with a hemoglobin level \< 10 g/dl at screening or a level that, in the opinion of the investigator, makes it unsafe for the subject to participate. * subjects with known hypersensitivity to cysteamine or penicillamine. * female subjects who are nursing, planning a pregnancy, known or suspected to be pregnant, or have a positive serum pregnancy screen. * subjects who, in the opinion of the investigator, are not able or willing to comply with the protocol.

Keywords: cystinosis cysteamine inheritable disease orphan disease ctns protein, human metabolic disease nephropathic cystinosis