Conditions: Cystinosis
Keywords: Nephropathic Cystinosis Cysteamine Delayed-Release Cysteamine Orphan Disease CTNS Protein, Human
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 41
Healthy volunteers: no

Brief summary:
The purpose of this study is to gather information about the effectiveness (how well it works to treat cystinosis) and safety of a new form of cysteamine bitartrate called RP103, compared to the already-approved drug cystinosis patients are taking called Cystagon®.

In cystinosis, the body builds up cystine. When taken regularly, the active ingredient of Cystagon® (cysteamine bitartrate) reduces cystine in the body. RP103 has the same active ingredient as Cystagon® and is designed to reduce cystine in a similar way that Cystagon® does. To decide if RP103 is better than Cystagon®, the study will look at two types of blood tests. One test is pharmacodynamics (PD), which measures the amount of white blood cell (WBC) cystine after taking study drug. WBC cystine is a laboratory test used to find out if cysteamine bitartrate is reducing cystine levels in the body. The second test is pharmacokinetics (PK), which measures the amount of cysteamine in the blood after taking the drug.

RP103 is different from Cystagon®: Instead of the cysteamine bitartrate being absorbed from the stomach, RP103 is designed to be absorbed from the small intestine. This may make the effects of the drug last longer, so that it can be taken twice a day instead of four times a day like Cystagon®.

Some cystinosis patients have bad breath (halitosis) when they take Cystagon®. Study participants who experience bad breath with Cystagon® will be asked if they would like to participate in an optional "halitosis substudy" to investigate this issue by collecting some extra PK blood samples.

Detailed description:
Study with completed results acquired from Horizon in 2024.

Arms:
arm 1: Cystagon® Phase: From Screening and during Months 1, 2, 3 participants receive their usual dose of Cystagon® every 6 hours (Q6H).

RP103 Phase: During Months 3.5, 4, 5, 6, 7 participants receive RP103 every 12 hours (Q12H).

Long Term Phase: On or after Month 7, for the remainder of study participants receive RP103 Q12H.

Interventions: intervention 1: RP103 intervention 2: Cystagon®
Intervention descriptions: intervention 1: None intervention 2: None

Protocol document: