Clinical trials

The goal of this clinical trial is to investigate oral TTI-0102 to evaluate its pharmacokinetics, safety, and preliminary efficacy in patients with Leigh syndrome spectrum, in three sequences. First sequence will be placebo-controlled and include 12 adolescents and adults weighing more than 40 kg. Second sequence will be open-label and include 3 adults and 3 children weighing 25-40 kg. Third sequence will also be open-label and will include 3 children weighing 20-25 kg. The main questions clinical trial aims to answer are: * Characterize the relationship between TTI-0102 drug levels by measuring 1. cysteamine pharmacokinetic (PK) parameters 2. pharmacodynamic (PD) efficacy measures * Generate a population PK model and determine dose level for later dosing groups * collect data to inform the design of a subsequent phase 2b/3 study of TTI-0102 in this patient population Participants will be asked to: * Take the study drug twice daily for 12 weeks * Visit the clinic for checkups and testing 7 times in total: once prior to study drug dosing, then 5 times over the 12-week treatment period and one more time a month after the last study drug dose.