An Open-label Extension Safety Study of MELAS Patients Who Completed TIS6463-203 (PRIZM)

Phase 2

Not yet recruiting

• Conditions: Mitochondrial Encephalopathy, Lactic Acidosis and Stroke-Like Episodes (MELAS Syndrome)
• Interventions: Drug: zagociguat 15mg

• Registration Number: NCT06961344
• Lead Sponsor: Tisento Therapeutics

Brief Summary

The goal of this clinical trial is to evaluate the long-term safety and tolerability of zagociguat in patients with MELAS who completed the lead-in study TIS6463-203. TIS6463-204 is evaluating zagociguat in an open-label extension study at the daily dose of 15mg. The study medication is a once daily oral table and will be provided at the clinic and/or shipped to the participant's home. Study assessments will be conducted during clinic visits which will occur at three months and then at six months. Thereafter, clinic visits will occur every six months.

Detailed Description

On Screening Visit Day -1 (which corresponds to Period 2 Week 12 Visit from lead-in study TIS6463-203), participants will sign the informed consent form, be confirmed eligible for this open-label extension study and undergo Screening Visit assessments. Eligible participants will begin dosing the next day on Day 1 (there is no Day 0) at home. Participants will have a 3-month visit and 6-month study visit at the clinic and thereafter will have a clinic visit every 6 months. Participants should have a Follow-up Visit 4 (+1) weeks after zagociguat discontinuation.

Study Timeline

• Status Verified: 2025-04
• Study First Submitted: 2025-04-28
• Study First Submitted QC: 2025-05-06
• Last Update Submitted: 2025-05-06
• Study First Posted: 2025-05-07
• Last Update Posted: 2025-05-07
• Study Start: 2025-08
• Primary Completion: 2028-03
• Study Completion: 2028-03

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 44

Inclusion Criteria

1. Signed an Institutional Review Board (IRB)/Independent Ethics Committee (IEC)-approved informed consent form (ICF).
2. Completed TIS6463-203 treatment through the Period 2 Week 12 Visit.
3. Agrees to follow lifestyle restrictions.
4. Other criteria per the protocol.

Exclusion Criteria

1. Any medical condition or clinical finding that, per investigator judgement, would preclude safe study participation and/or completion of all trial requirements.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Zagociguat 15mg	zagociguat 15mg	Participants receive zagociguat 15 mg once a day (QD) for the duration of the study.

Primary Outcome Measures

Name	Time	Method
Incidence of Treatment-emergent Adverse Events (TEAEs)	Day 1 through the Follow-up for treatment period 4 weeks after last dose of study medication.	TEAEs are any untoward event that may or may not be related to study medication.