Efficacy of KL1333 in Adult Patients With Primary Mitochondrial Disease

The primary objective of the FALCON study is to evaluate the efficacy of KL1333 on selected disease manifestations of primary mitochondrial disease (PMD) following 48 weeks of treatment. This objective involves evaluating the efficacy of KL1333 versus placebo on fatigue symptoms and impacts on daily living as well as on functional lower extremity strength and endurance. Additionally, the study evaluates the safety and tolerability of KL1333.

• : * Age 18 years or older. * A confirmed PMD diagnosis caused by a known pathogenic gene mutation or deletion of the mitochondrial genome (category 6 of the International Classification of Inborn Metabolic Disorders [ICIMD])12 according to American College of Medical Genetics (ACMG)/Association of Molecular Pathology (AMP) criteria1, with multisystemic disease expressions, including: 1. m.3243A>G associated MELAS-MIDD spectrum disorders, 2. single large scale mtDNA deletion associated KSS-CPEO spectrum disorders, 3. other multisystemic mtDNA-related disease (including MERRF). * Presence of chronic mitochondrial fatigue: * History of mitochondrial fatigue for at least 3 months prior to the Screening Visit AND * Presence of at least moderate level of fatigue, assessed by PROMIS® Fatigue PMD Short form raw score ≥ 27 at Screening and Baseline * Presence of mitochondrial myopathy defined as: * Myopathy (proximal muscle weakness), NMDAS Section III Clinical Assessment, item 5 score ≥ 1, which reads: "minimal reduction in hip flexion and/or shoulder abduction only (e.g. MRC 4+/5)". For the inclusion only hip flexion, but not shoulder abduction, should be taken into account. AND / OR * Exercise Tolerance: NMDAS Section I, item 9 score ≥ 1, which reads: "unlimited on flat - symptomatic on inclines or stairs".…

Use the source registry for the full inclusion and exclusion criteria before discussing referral or enrolment.