NCT06549400

An Open-Label Extension Study to Evaluate the Long-Term Safety and Efficacy of Once Daily Mexiletine PR in Patients With Myotonic Dystrophy Type 1 and Type 2 Who Have Completed MEX-DM-302 Study.

An Open-Label Extension Study to Evaluate the Long-Term Safety and Efficacy of Once Daily Mexiletine PR in Patients With Myotonic Dystrophy Type 1 and Type 2 Who Have Completed the MEX-DM-302 Study (ATLAS Study)

• Status: Enrolling By Invitation
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 176 (estimated)
• Sponsor: Lupin Ltd. · Industry
• Sex: All
• Age: 16 Years
• Healthy volunteers: Not accepted

Summary

This is an open-label extension study intended to evaluate the long-term safety and efficacy of mexiletine PR in patients with myotonic dystrophy type 1 and type 2 (DM1 and DM2) who have completed the parent study MEX-DM-302.

Detailed description

At the completion of the final visit in Study MEX-DM-302 patients who continued to meet the eligibility criteria will be invited to rollover into this open-label study for an additional 18 months. All patients who elect to continue into this open-label study will receive active mexiletine (no placebo). Mexiletine PR will be started as 167 mg once a day (QD) treatment regimen. The dose will be titrated up at Week 1 to 333 mg and at Week 2 to a maximum dose of 500 mg QD depending on tolerability. If unable to tolerate the escalated dose, the dose will be reduced by one dose step during the titration period of the study to a maximum tolerated dose. Study drug should be taken with food at approximately the same time of the day every day, preferably in the morning (See Section 7 for further details on reconstitution and dosing titration). Safety assessments include patient- and physician-reported adverse events, standard clinical laboratory evaluations, physical examinations, and vital signs. In addition, ECG, Holter monitors, and echocardiogram assessments will be collected to assess cardiac safety during the study.

Conditions

• Myotonic Dystrophy

Interventions

Type	Name	Description
DRUG	Mexiletine granules for prolonged-release oral suspension	Mexiletine PR

Timeline

• Start date: 2025-09-12
• Primary completion: 2028-05-29
• Completion: 2028-07-06
• First posted: 2024-08-12
• Last updated: 2026-01-26

Locations

6 sites across 6 countries: Belgium, Denmark, Germany, Italy, Spain, United Kingdom