Clinical trial Recruiting at 7 sites Phase 3 Interventional Ages 18 and up

Sonlicromanol for symptoms of primary mitochondrial disease due to the m.3243A>G mutation

Official title: A Phase III, Randomised, Double-blind, Placebo-controlled, Parallel-group, Pivotal Trial to Assess the Efficacy and Safety of Sonlicromanol in Adult Subjects With a Genetically Confirmed Mitochondrial DNA tRNALeu(UUR) m.3243A>G Variant

Run by Khondrion BV · NCT06451757 · Data updated 2026-11-12

This will test whether taking sonlicromanol twice daily for one year can reduce fatigue and improve balance and leg strength in adults with the m.3243A>G mitochondrial mutation.

More Mitochondrial Diseases trials

Quick facts

PhasePhase 3
Study typeInterventional
Ages18 Years and up
SexAll
Enrollment220 (estimated)
SponsorKhondrion BV
Industry-sponsored
Locations10 sites (Boston, Massachusetts and 9 other locations)
StatusRecruiting
StartedApril 14, 2026
Main results expectedSeptember 2029
Study endsSeptember 2029
Registry record updatedOctober 14, 2026
Trial IDNCT06451757 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Adults (≥18 years) with multi-system primary mitochondrial disease caused by the m.3243A>G mutation who meet the age-adjusted heteroplasmy threshold (≥20% by approved sample types), report chronic fatigue for ≥3 months with a Neuro-QoL fatigue score >22, and can complete the 5x sit-to-stand test are ideal candidates.

Probably not a fit

People without the m.3243A>G mutation or with heteroplasmy below the required threshold, those whose fatigue is due to other causes, or those unable to complete the required physical tests are unlikely to meet eligibility or benefit from this trial.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

KHENERFIN is a randomized, double-blind, placebo-controlled Phase 3 trial comparing sonlicromanol to a matched placebo in adults with primary mitochondrial disease caused by the m.3243A>G mutation. Participants are randomly assigned to take sonlicromanol or placebo tablets twice daily for 52 weeks, with a final follow-up visit two weeks after the last dose. Primary outcomes measure changes in fatigue severity and the impact of fatigue on daily life, along with balance control and lower-limb muscle strength; a range of secondary and exploratory outcomes plus safety and tolerability are also collected. Eligibility is confirmed during a screening period (up to 4 weeks) and requires specified heteroplasmy thresholds, chronic fatigue, and the ability to complete the 5x sit-to-stand test.

Why it matters

Potential benefit: If successful, sonlicromanol could reduce fatigue and improve mobility and leg strength, which may help people with the m.3243A>G mutation perform daily activities more easily.

How similar studies have gone: Prior early-phase studies of sonlicromanol and similar mitochondrial-targeted approaches have shown some promising signals on symptoms or biomarkers, but large randomized Phase 3 evidence is limited.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion criteria

1. Signed Informed Consent
2. Males and females aged ≥18 years with a multi-system primary mitochondrial disease.
3. A confirmed mitochondrial DNA tRNALeu(UUR) m.3243A\>G mutation (m.3243A\>G PMD) plus an age adjusted heteroplasmy percentage ≥ 20% in white blood cells \[=blood heteroplasmy/0.977(age+12)\]. Or in urine (urinary epithelial cells), or buccal smear or skeletal muscle (results (obtained per local guidance) ≥ 20% must be available prior to the subject being randomized).
4. Presence of chronic fatigue (not attributable to other etiologies than PMD):

   1. Patient self-reported chronic fatigue for at least 3 months prior to the Screening Visit and recorded in the clinical patient files; AND
   2. Presence of fatigue (raw total score \>22), assessed by Neuro-QoL SFv1-F at Screening.
5. Presence of mitochondrial myopathy defined as:

5xSST at Screening and Baseline should be ≥ 11 seconds and participant must demonstrate the ability to complete the test at baseline (i.e., complete the test within 30 seconds).

6\. Other Inclusion criteria per protocol.

Exclusion criteria

1. Treatment with any IMP within 3 months (or 5 times the half-life of the IMP, whichever is longer) prior to screening or plans to use an IMP (other than the study intervention) during the study.
2. Bone deformities, motor abnormalities or chronic ulcers that in the opinion of the PI may interfere with and/or confound the interpretation of the subject's performance during the 5 times sit to stand test (5XSST).
3. Surgery of gastrointestinal tract that might interfere with drug absorption. Or severe GI dysmotility, chronic vomiting, diarrhea, bouts of pseudo-obstruction which will impair appropriate IMP absorption in the opinion of the investigator.
4. Clinically significant respiratory disease and/or cardiac disease (medical history or current clinical findings) in the opinion of the investigator.
5. Prior interventional cardiac procedure (e.g., cardiac catheterization, angioplasty/percutaneous coronary intervention, balloon valvuloplasty, etc.) within 3 months prior to screening.
6. Structural heart disease based on cardiac MRI or Echocardiography (e.g., clinically significant valve disease; i.e., aortic or mitral valve stenosis or regurgitation) and / or Left ventricular dysfunction (LVEF \<52% in men and \< 54% in women) and / or congestive cardiac failure (more severe than grade II) and / or Maximum left-ventricular septal or posterior wall thickness \> 15 mm and / or Evidence of active myocardial ischaemia, ECG evidence and / or recent history of myocardial infarction (\< 6-months) and / or coronary angioplasty / coronary bypass surgery (\< 12 months).
7. Family history of unexplained/uninvestigated syncope or congenital long and short QT syndrome or sudden death (under the age of 60) and / or Abnormal QTcF interval \[QTcF \> 450 msec (men) or QTcF \> 470 msec (women) = abnormally long QTcF or QTcF \< QT \< 320ms = abnormally short QtcF\] and / or Intermittent or persistent WPW (pre-excitation) syndrome on ECG \[ie: abnormally wide QRS \> 120ms with slurred up-stroke ('delta' wave) and PR-interval \< 120ms\] and / or ECG evidence of atrial fibrillation (permanent, persistent or paroxysmal) and / or

   High grade AV Block \[2nd-degree AV block Type II (ie: 2:1) or complete AV block (3rd degree) or intermittent conduction system abnormalities with the exception of any of the following:
   * 1st degree atrioventricular (AV)-block
   * 2nd degree AV-block Type 1 (Mobitz Type 1 / Wenckebach type)
   * Right bundle branch block.
8. History of acute heart failure (within the last 3 months).
9. Higher degree of AV-blocks (AVB II° or III°).
10. Other exclusion criteria per protocol

Where it's running

  • The University of Texas Health Science Center at Houston
    Houston, Texas, United States
    Recruiting
  • Rigshospitalet, University of Copenhagen
    Kopenhagen, Region Sjælland, Denmark
    Recruiting
  • Groupe Hospitalier Pitie-Salpetriere - Charles-Foix Clinical Investigation Center Paris-Est
    Paris, Paris, France
    Recruiting
  • Klinikum der Universität München Friedrich-Baur-Institut
    München, Germany
    Recruiting
  • Fondazione IRCCS Istituto Neurologico Carlo Besta
    Milan, Italy
    Recruiting
  • Radboud University Medical Center
    Nijmegen, Gelderland, Netherlands
    Recruiting
Show 4 more locations
  • University College London Hospitals NHS Foundation Trust National Hospital for Neurology and Neurosurgery
    London, Greater London, United Kingdom
    Recruiting
  • Massachusetts General Hospital
    Boston, Massachusetts, United States
    Not yet recruiting
  • Cleveland Clinic Neurological Institute Mellen Center
    Cleveland, Ohio, United States
    Not yet recruiting
  • CHU de Bordeaux - Hôpital Pellegrin Service Gynecologie Obstetrique
    Bordeaux, Gironde, France
    Not yet recruiting

Study contacts

Similar studies

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How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.