Pilot Study of Safety, Tolerability, Pharmacokinetics/Pharmacodynamics of RP103 Compared to Cystagon® in Patients With Cystinosis

Study Overview
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Brief Summary
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Cystinosis is an inheritable disease that if untreated, results in kidney failure as early as the first decade of life. The current marketed therapy is Cystagon® (cysteamine bitartrate) which must be taken every six hours for the rest of the patient's life to prevent complications of cystinosis. RP103 is a formulation of cysteamine bitartrate that is being studied to see if it may be able to be given less frequently, once every 12 hours, and have similar results.

Detailed Description
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This is a single-dose, open-labeled, non-randomized, two-period study of Cysteamine Bitartrate Delayed-release Capsules (RP103) and Cystagon® in up to 10 patients (male or female) with nephropathic cystinosis under fasting conditions. It will involve a 4 night check-in to a clinical research center.

Official Title
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A Pilot Study to Assess the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of Cysteamine Bitartrate Delayed-release Capsules (RP103), Compared to Cysteamine Bitartrate (Cystagon®) in Patients With Nephropathic Cystinosis

Conditions
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Cystinosis

Intervention / Treatment
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* Drug: Cystagon®
* Drug: RP103


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male and female subjects must have nephropathic cystinosis. Children less than 22.5 kg will only be included in the study if the investigator feels they can safely participate in the study including the required blood draw volume for the safety and PK/PD assessments. Subjects must be on a stable dose of Cystagon® at least 21 days prior to Screening. Subjects must be able to swallow a 150 mg Cystagon® capsule with the capsule intact. Within the last 2 months, no clinically significant change in liver function [i.e., ALT, AST, alkaline phosphatase, bilirubin (total and direct)] and renal function [i.e., serum creatinine, albumin, total protein] at Screening as determined by the Investigator. 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 or their authorized caregiver must provide written informed consent and assent (where applicable) prior to participation in the study. If in the opinion of the investigator, patients can safely provide the study required blood draw volume. Subjects must be willing and able to comply with the study restrictions and requirements. Exclusion Criteria: If, in the opinion of the investigator, the planned study dose would exceed the patient's tolerability of cysteamine based on their prior Cystagon® steady state drug requirements. Evidence of or verbal attestation of Helicobacter pylori infection, presently, or within the last 90 days prior to Screening. Subjects with a known history, currently or within the past 90 days prior to Screening, of the following conditions or other health issues that make it, in the opinion of the investigator, unsafe for them to participate, or whose concomitant medical problems preclude them from committing to the study schedule including the following: Crohn's disease, inflammatory bowel disease (if currently active) or have had prior resection of small intestine; • History of heart disease, e.g., myocardial infarction, heart failure, arrhythmias; Any bleeding disorder; Malignant disease; Severe liver disease as defined as ALT or AST > 2 times the upper limit of normal. Subjects who have had a kidney transplant. Subjects who are planning or are a registered candidate for a kidney transplant within 3 months of the Screening or have a serum creatinine > 2.4. Subjects with known hypersensitivity to cysteamine. If female (of child-bearing potential), are nursing, planning a pregnancy, known or suspected to be pregnant, or have a positive urine pregnancy screen. Patients with a hemoglobin level < 10.5. Subjects who have a made a blood donation within 60 days prior to study initiation. Subjects who, in the opinion of the Investigator, are not able or willing to comply with the protocol.
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Cystagon®<br>Reference Product: Cystagon® (Cysteamine Bitartrate) Capsules, 150 mg/50 mg | Drug: Cystagon®<br>* Reference Product: Cystagon® (Cysteamine Bitartrate) Capsules, 150 mg/50 mg. Duration of Treatment and Dose: Reference Period up to four doses Q6H.<br>|
| Experimental: RP103<br>Test Product: RP103 (Cysteamine Bitartrate) Delayed-release Capsules, 75 mg | Drug: RP103<br>* Test Product: RP103 (Cysteamine Bitartrate) Delayed-release Capsules, 75 mg. Duration of treatment and Dose: Single dose of Test Product at dose equivalent to Reference Product.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma Pharmacokinetic Parameter: Cmax of Cysteamine |  | 12 hours post RP103 dosing and 7 hours post 1st Cystagon® dosing | 
| Plasma Pharmacokinetic Parameter: Tmax of Cysteamine |  | 12 hours post RP103 dosing and 7 hours post 1st Cystagon® dosing | 
| Plasma Pharmacokinetic Parameter: AUC(0-t) of Cysteamine | t = 6 for Cystagon and t = 12 for RP103. Cystagon is dosed every 6 hours and there is no measurement after 6 hours and up to 12 hours. | 12 hours post RP103 dosing and 6 hours post 1st Cystagon® dosing | 
| Pharmacodynamic Parameter: Changes of White Blood Cell (WBC) Cystine Level From Baseline | The pharmacodynamic (PD) parameter measures the changes of WBC cystine level from the baseline. Cystine is a disulfide amino acid formed through oxidation of two molecules of cysteine; hence, cystine's concentration is commonly given in half-cystine equivalents to avoid confusion. The level of cystine in WBC/leukocytes is expressed in units of nmol half-cystine/mg protein (nmol ½ cystine/mg protein). Half-cystine is quantified by a reduction of cystine followed by an assay for cysteine, which is then normalized by the total cellular protein content within the sample using methods of such as Lowry assay, bicinchoninic acid assay, or Bradford. | up to 12 hours post Cystagon® dosing and RP103 dosing | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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cystinosis, cysteamine, inheritable disease, orphan disease, CTNS protein, human, nephropathic cystinosis