Evaluating zagociguat for treating MELAS syndrome

Phase 2b Randomized, Double-blind, Placebo-controlled Crossover Study Evaluating the Efficacy and Safety of Zagociguat in Participants With MELAS (PRIZM)

Phase 2 Interventional Tisento Therapeutics · NCT06402123

This study is testing if a new oral medication called zagociguat can help people with MELAS syndrome feel less tired and think better.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment44 (estimated)
Ages18 Years to 75 Years
SexAll
SponsorTisento Therapeutics Industry-sponsored
Locations25 sites (La Jolla, California and 24 other locations)
Trial IDNCT06402123 on ClinicalTrials.gov

What this trial studies

This clinical trial is a Phase 2b randomized, double-blind, placebo-controlled study assessing the efficacy and safety of oral zagociguat in patients with MELAS. Participants will receive either zagociguat at two different doses or a placebo over two 12-week treatment periods, separated by a 4-week washout. The study aims to determine if zagociguat can improve fatigue and cognitive performance in these patients while also evaluating its safety and tolerability. Participants will engage in regular assessments through clinic visits and a mobile app to monitor their progress.

Who should consider this trial

Good fit: Ideal candidates for this study are adults aged 18 to 75 diagnosed with MELAS who experience fatigue and have specific genetic markers.

Not a fit: Patients with severe gastrointestinal issues or significant active cancer may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the quality of life for patients suffering from MELAS by alleviating fatigue and enhancing cognitive function.

How similar studies have performed: While this approach is novel for MELAS, similar studies targeting mitochondrial disorders have shown promising results.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Signed consent form.
2. 18 to 75 years of age.
3. Diagnosed with MELAS based on the presence of each of the following criteria:

   1. A documented pathogenic variant in a mitochondrial DNA (mtDNA) gene.
   2. History of one or more stroke-like episodes (SLEs) with magnetic resonance imaging (MRI) findings consistent with stroke-like lesions.
4. Scores below normal average on the iDSST and GMLT.
5. Reports fatigue due to MELAS.
6. Can complete at least 1 sit-to-stand in the 30-second test interval.
7. Completes all at-home weekly activities independently during the Screening Period (caregiver may help set up device/app, log-in, etc.).
8. Other criteria per the protocol.

Exclusion Criteria:

1. Systolic blood pressure (BP) 90 mmHg or diastolic BP 60 mmHg.
2. Orthostatic hypotension when measured after standing from a semi-recumbent/supine position.
3. Active cancer significant enough to confound the results of this study.
4. Severe gastrointestinal dysmotility that may impact participation.
5. Recent history (within last 6 months) of platelet dysfunction, hemophilia, von Willebrand disease, coagulation disorder, other bleeding diathesis condition(s), or significant, nontraumatic bleeding episodes.
6. History of spontaneous fracture(s) that in the investigator's opinion represents a safety risk for trial participation.
7. Current use of prohibited medication (reviewed by investigator).
8. Any medical or other condition that the investigator thinks would preclude study participation.
9. Other exclusion criteria per protocol.

Where this trial is running

La Jolla, California and 24 other locations

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Mitochondrial Encephalopathy, Lactic Acidosis and Stroke-Like EpisodesMELAS
Last reviewed 2026-06-09 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.