Conditions: Inherited Mitochondrial Disease, Including Leigh Syndrome
Keywords: Leigh Syndrome Leber's hereditary optic neuropathy myoclonic epilepsy mitochondrial encephalomyopathy Kearn-Sayre syndrome POLG-related disorders Neurogastrointestinal encephalopathy
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 36
Healthy volunteers: no

Brief summary:
To evaluate safety, tolerability and efficacy of cysteamine bitartrate delayed-release capsules (RP103) administered at a target maintenance dose of 1.3 g/m²/day in two divided doses, every 12 hours, for up to 6 months in patients with inherited mitochondrial disease.

Detailed description:
This is an open-label, dose-escalation study to assess the safety, tolerability, efficacy, pharmacokinetics and pharmacodynamics of cysteamine bitartrate delayed-release capsules (RP103) for treatment of children with inherited mitochondrial disease.

Prior to treatment, patients will undergo a Screening Visit. If eligible, each participant will return for the Day 1 study visit and begin dosing. Every 2 weeks over the subsequent 8 weeks, participants will alternate between returning to the clinic for detailed assessments (Weeks 4 and 8) and receiving a telephone call from the Investigator team to assess safety and RP103 dose (Weeks 2 and 6) and the potential need for an immediate unscheduled study visit. Thereafter, participants will continue to return to the clinic every 4 weeks for detailed assessments at Weeks 12, 16, 20, and 24 (the Study Exit visit).

The Study Exit visit will occur at Week 24, and participants will be offered the opportunity to continue on to an extension study (RP103-MITO-002 \[NCT02473445\]) until results of the present study are known.

Study with completed results acquired from Horizon in 2024.

Arms:
arm 1: Cysteamine bitartrate delayed-release capsules were administered twice daily following a dose-escalation design with a progressive weekly dose increase over the first 6 weeks. The starting dose was 0.2 g/m²/day, up to a maximum dose of 1.3 g/m²/day. Participants remained on their highest tolerated dose until Week 24.

Interventions: intervention 1: Cysteamine Bitartrate
Intervention descriptions: intervention 1: Cysteamine Bitartrate Delayed-release capsules

Protocol document: