NCT05650229 · Abliva AB
Efficacy of KL1333 in Adult Patients With Primary Mitochondrial Disease
(FALCON)
What this study is about
The primary objective of the FALCON study is to evaluate the effectiveness of KL1333 on selected disease manifestations of primary mitochondrial disease (PMD) following 48 weeks of treatment. This objective involves evaluating the effectiveness of KL1333 versus placebo on fatigue symptoms and impacts on daily living as well as on functional lower extremity strength and endurance.
View original scientific description
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.
Interventions
DRUG
KL1333
Twice daily
DRUG
Placebo
Twice daily
Primary outcome measures
Change in-patient-reported fatigue symptoms and impacts on daily living measured by Patient-Reported Outcomes Measurement Information System (PROMIS®) Fatigue PMD Short Form
Time frame: Baseline and 48 Weeks
Change in t-score. Higher scores indicate greater fatigue severity.
Change in 30 Second Site-to-Stand Test.
Time frame: Baseline and 48 Weeks
Change in number of stands
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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 Clini
Where
- Orange, California
- San Diego, California
- San Francisco, California
- Aurora, Colorado
- New Haven, Connecticut
- Miami, Florida
- Atlanta, Georgia
- Indianapolis, Indiana
- Baltimore, Maryland
- Rochester, Minnesota
- St Louis, Missouri
- Marlboro, New Jersey
And 6 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 26, 2026 · Source of record for eligibility and locations