Myotonic DystrophyPhase 3NCT06549400
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.
A Phase 3 study testing Mexiletine granules for prolonged-release oral suspension in people with Myotonic Dystrophy, run by Lupin Ltd. at 6 sites in 6 countries.
Trial 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. Read more about this study
- Who is it for?
- Ages 16 years and older
- Conditions the study is for
- Myotonic Dystrophy
- What is being tested?
- Mexiletine granules for prolonged-release oral suspension
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 176 participants
- Where
- 6 sitesin 6 countries
- Study dates
- 12 Sep 2025to 6 Jul 2028
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 16 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- DM1 or DM2 diagnosis confirmed genetically;
- Ability to comprehend and willingness to sign an informed consent (ICF) or ICF of the parent(s)/legal guardian and written assent from the patient (if patient < 18 years of age);
- Ability to understand the study requirements including intention to stay in the study until the end-of-study visit at 26 weeks of treatment;
- Male or non-pregnant female ≥16 years of age;
- Body Mass Index (BMI) of 18.5 kg/m2 to 30 kg/m2, and weight ≥45 kg;
- Female patients of childbearing potential must be using a highly effective form of birth control for the duration of the study and for at least 7 days after last dose of study drug;
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- No significant cardiac abnormalities as determined by a cardiologist's assessment;
- Have sufficient finger flexor strength to grasp the handle of the dynamometer used to measure myotonia;
- DM1 patients only - Muscular impairment rating scale (MIRS) score of 2, 3 or 4.
Who cannot join
- Are pregnant or lactating;
- Have any one of the following medical conditions: uncontrolled diabetes mellitus, cancer other than skin cancer less than five years previously (e.g., basal-cell carcinoma (BCC) and squamous-cell carcinoma (SCC) of skin allowed), multiple sclerosis, seizure disorders, or other serious medical illness;
- Severe renal impairment (glomerular filtration rate (GFR) < 30 mL/min);
- Medical conditions which could interfere with muscle function such as infections, trauma, fractures, or planned surgery;
- Medical conditions that could affect hand functioning including but not limited to rheumatoid arthritis, Dupuytren's contracture, hand deformity, etc.;
- Severe arthritis or medical condition (other thanDM1/DM2) that would significantly impact ambulation;
Show all 27Show fewer
- High incidence of falls or fall-associated fractures (>5 falls during the past 12 months);
- Preexisting elevated liver function tests > 3 times the upper limit of normal (ULN) on Day 1 (alanine transaminase (ALT)/aspartate transaminase (AST), gamma-glutamyl transferase (GGT)) and/or any abnormal chemistry, hematology or urine lab considered clinically significant by investigator;
- Serum potassium values < 3.5 mmol/L or > 5.0 mmol/L or serum magnesium values < 1.7 mg/dL. Electrolytic imbalance such as hypokalaemia, hyperkalaemia or hypomagnesaemia may increase the proarrhythmic effects of mexiletine. Electrolyte imbalances need to be corrected before administering mexiletine and will be monitored throughout treatment.
- Intake of any anti-myotonic treatment within 4 weeks prior to baseline (Day 1) or 5 half-lives, whichever is longer such as metformin, such as propafenone, flecainide, lamotrigine, carbamazepine or any other channel-blocker/ anticonvulsive drugs;
- Use of any concomitant medications that could increase the cardiac risk;
- Known allergy to mexiletine or any local anesthetics;
- Participation in another interventional clinical study during the last 3 months or 5 half-lives of the investigational medicinal product, whichever is longer (with the exception of participation in the previous MEX-DM-302 study);
- Wheelchair-bound or bed-ridden;
- Any cardiac safety associated condition including any of the following criteria detected by cardiac evaluations including 24-hr Holter monitor, echocardiogram and clinical evaluations:
- PR interval ≥240 ms or QRS duration ≥120 ms on resting ECG
- Personal history of 3rd degree or 2nd degree type 2 atrioventricular block or sinus node dysfunction with pauses ≥3 seconds, complete bundle branch block, bifascicular and trifascicular block or any heart block susceptible to evolve to complete heart block
- Personal history of sustained atrial fibrillation, flutter or tachycardia (duration >30 seconds)
- Personal history of non-sustained (ventricular triplets or more) or sustained ventricular tachycardia
- Myocardial infarction (acute or past) or coronary artery stenosis >50%, presence of abnormal Q waves
- New York Heart Association (NYHA) Class II to IV heart failure
- Left ventricular systolic dysfunction with ejection fraction <50%
- Sinus node dysfunction (including ECG sinus rate <50 beats per minute (BPM))
- Co-administration of antiarrhythmics inducing torsades de pointes (class Ia: quinidine, procainamide, disopyramide, ajmaline; class Ic: encainide, flecainide, propafenone, moricizine; class III: amiodarone, sotalol, ibutilide, dofetilide, dronedarone, vernakalant)
- Co-administration of other classes of antiarrhythmics (class Ib: lidocaine, phenytoin, tocainide; class II: propranolol, esmolol, timolol, metoprolol, atenolol, carvedilol, bisoprolol, nebivolol; class IV: verapamil, diltiazem)
- Patients with implantable cardioverter defibrillators (ICDs) and pacemakers are excluded
- Presence of symptomatic coronary artery disease
Trial locations and contacts
6 sites in 6 countries. Contact the study team or a site near you to ask about taking part.
6 sites in 6 countries
About this study
Official title: 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)
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.
Read the 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
- Being tested
- Mexiletine granules for prolonged-release oral suspension
- Medical subject headings
- Myotonic Dystrophy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Mexiletine granules for prolonged-release oral suspensionDrug
Mexiletine PR
| Study group | Role | What they receive |
|---|---|---|
| Mexiletine prolonged-release (PR) | Other | Mexiletine PR 167 mg (mexiletine HCl 200 mg) Mexiletine PR 333 mg (mexiletine HCl 400 mg) OR Mexiletine PR 500 mg (mexiletine HCl 600 mg) Receives: Drug: Mexiletine granules for prolonged-release oral suspension |
What is being measured
The primary outcome is the main question the study is designed to answer.
To assess the long-term efficacy of once daily mexiletine PR for the symptomatic treatment of myotonia in patients with myotonic dystrophy type 1 and type 2 (DM1 and DM2) who have completed MEX-DM-302 study.
Handgrip relaxation time in DM1 patients by mean change in baseline of handgrip relaxation time (seconds) after maximal voluntary isometric contraction (MVIC)
Measured: 78 weeks
Secondary outcomes (27)
To assess the long-term safety of once daily mexiletine PR for the symptomatic treatment of myotonia in patients with myotonic dystrophy type 1 and type 2 (DM1 and DM2) who have completed the MEX-DM-302 study
Number and frequency of AEs/SAEs throughout the study while on treatment
Measured: 78 weeks
Mean change in VAS
Score for muscle stiffness (myotonia severity) as self-reported by patients on a Visual Analog Scale (VAS)
Measured: 78 weeks
Mean change in MBS scores
Mean change in Myotonia Behavior Scale (MBS) scores on a scale of 0 (no stiffness) to 5 (incapacitating stiffness)
Measured: 78 weeks
Mean change in health-related quality of life
Mean change in health-related quality of life (measured by INQoL)
Measured: 78 weeks
Mean change in DM1-Activ-c scale (DM1 patients only)
Mean change in measure of activity and social participation (measured by a Rasch-built scale with a 0-100 interval range)
Measured: 78 weeks
Mean change in time to perform the 10-meter Walk Test
Mean change in time (seconds) to perform the 10-meter Walk Test (10mWT)
Measured: 78 weeks
Mean change in handgrip relaxation time
Mean change in maximal voluntary isometric contraction (MVIC) and relaxation time by Video-recording of Hand Opening Time (VHOT) functional evaluation
Measured: 78 weeks
Mean change in time to perform Timed-up and go (TUG) test
Mean change in time (seconds) to perform Timed-up and go (TUG) test
Measured: 78 weeks
Mean change in health-related quality of life measured by EQ-5D
Mean change in health-related quality of life measured by EQ-5D (5-point scale)
Measured: 78 weeks
Mean change in Myotonic Dystrophy Health Index (MDHI) score (DM1 patients)
Mean change in Myotonic Dystrophy Health Index (MDHI) score (DM1 patients) as measured by patient's perceived health
Measured: 78 weeks
Mean change in Myotonic Dystrophy 2 Health Index (MD2HI) score (DM2 patients)
Mean change in Myotonic Dystrophy 2 Health Index (MDHI) score (DM2 patients) as measured by patient's perceived health
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by changes in ECG
Mean change in ECG (PR, QRS, and QTc intervals in units of milliseconds [ms]) from baseline
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by changes in ECG (HR)
Mean change in ECG (HR in units of beats per minute) from baseline
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by AEs
Incidence of treatment emergent adverse events (TEAEs), treatment-related TEAEs, serious AEs, and patient discontinuation rate
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (hematology measured in units of μL [microliters]) from change in baseline
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations as measured by hematology parameters in units of μL: white blood cell (WBC) with differential (absolute count), red blood cells (RBC), platelet count, and red blood cell indicies.
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (hematology measured in units of % [percentage]) from change in baseline
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations as measured by hematology parameters in units of %: white blood cell (WBC) and differential (percentage) and hematocrit.
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (hematology measured in g/dL [units of grams per deciliter]) from change in baseline
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations as measured by hematology parameters in units of g/dL: hemoglobin.
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (chemistry measured in units of mmol/L) from change in baseline
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations as measured by chemistry parameters in units of mmol/L: chloride, carbon dioxide, potassium, and sodium
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (chemistry measured in units of U/L) from change in baseline
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations as measured by chemistry parameters in units of U/L: alkaline phosphatase, aspartate aminotransferase (AST), aspartate transaminase (ALT), gamma-glutamyl transferase (GGT), and creatine phosphokinase.
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (chemistry measured in units of g/dL) from change in baseline
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations as measured by chemistry parameters in units of g/dL: albumin and total protein.
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (chemistry measured in units of mg/dL) from change in baseline
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations as measured by chemistry parameters in units of mg/dL: blood urea nitrogen (BUN), calcium, creatinine (eGFR), glucose, total bilirubin, and magnesium.
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (urinalysis) from change in baseline
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations as measured by urinalysis parameters (measured as normal or abnormal): appearance, specific gravity, pH, protein, glucose, ketones, blood, leukocyte esterase, nitrite, bilirubin, urobilinogen, and microscopic examination.
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by vital signs (pulse)
Assess the long-term safety of mexiletine PR by vital signs (pulse in units of bpm [beats per minute]) from change in baseline
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by vital signs (body temperature)
Assess the long-term safety of mexiletine PR by vital signs (body temperature in units of Fahrenheit or Celsius) from change in baseline
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by vital signs (blood pressure)
Assess the long-term safety of mexiletine PR by vital signs (blood pressure [diastolic and systolic] in units of mmHg [millimeters of mercury]) from change in baseline
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by vital signs (respiration)
Assess the long-term safety of mexiletine PR by vital signs (respiration in units of breaths per minute) from change in baseline
Measured: 78 weeks
Assess the long-term safety of mexiletine PR by physical examinations
Assess the long-term safety of mexiletine PR by change in baseline from physical examinations (normal or abnormal) in the following regions and systems: general appearance, head and neck, heart, lung, abdomen, chest and back, upper extremities, lower extremities, neurological, and dermatological.
Measured: 78 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Aug 2024
- Study start12 Sep 2025
- Primary completion29 May 2028 (estimated)
- Study completion6 Jul 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Myotonic DystrophyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- This is an open-label extension study intended to evaluate the continuous long-term (18 months) safety and efficacy of once daily mexiletine-prolonged release (mexiletine PR) for the symptomatic treatment of myotonia in patients with myotonic dystrophy type 1 and type 2 (DM1 and DM2) who have completed the parent study MEX-DM-302. The MEX-DM-302 is a multicenter, randomized, double-blind, parallel-group, placebocontrolled study intended to evaluate the safety and efficacy of mexiletine PR in patients with DM1 and DM2) for 6 months. At the completion of the final visit in Study MEX-DM-302 patients who continue 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 PR (no placebo).
- Masking
- None (open label)
- Enrolment
- 176 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Lupin Ltd.
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Lupin Atlantis Holdings S.A.
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06549400
- Sponsor's protocol ID
- MEX-DM-303
- Status last verified
- Jan 2026
- First submitted
- 9 May 2024
- Last updated
- 26 Jan 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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)
- ClinicalTrials.gov ID
- NCT06549400
- Acronym / sponsor ID
- MEX-DM-303
- Conditions
- Myotonic Dystrophy
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 176 participants (estimated)
- Lead sponsor
- Lupin Ltd.Industry (pharma, biotech, devices)
- Collaborators
- Lupin Atlantis Holdings S.A.
- Study start
- 12 Sep 2025 (actual)
- Primary completion
- 29 May 2028 (estimated)
- Study completion
- 6 Jul 2028 (estimated)
- First posted
- 12 Aug 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- This is an open-label extension study intended to evaluate the continuous long-term (18 months) safety and efficacy of once daily mexiletine-prolonged release (mexiletine PR) for the symptomatic treatment of myotonia in patients with myotonic dystrophy type 1 and type 2 (DM1 and DM2) who have completed the parent study MEX-DM-302. The MEX-DM-302 is a multicenter, randomized, double-blind, parallel-group, placebocontrolled study intended to evaluate the safety and efficacy of mexiletine PR in patients with DM1 and DM2) for 6 months. At the completion of the final visit in Study MEX-DM-302 patients who continue 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 PR (no placebo).
| Arm | Type | Receives |
|---|---|---|
| Mexiletine prolonged-release (PR) | Other | Drug: Mexiletine granules for prolonged-release oral suspensionMexiletine PR 167 mg (mexiletine HCl 200 mg) Mexiletine PR 333 mg (mexiletine HCl 400 mg) OR Mexiletine PR 500 mg (mexiletine HCl 600 mg) |
Who may qualify
- Ages
- 16 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (9 listed)
- DM1 or DM2 diagnosis confirmed genetically;
- Ability to comprehend and willingness to sign an informed consent (ICF) or ICF of the parent(s)/legal guardian and written assent from the patient (if patient < 18 years of age);
- Ability to understand the study requirements including intention to stay in the study until the end-of-study visit at 26 weeks of treatment;
- Male or non-pregnant female ≥16 years of age;
- Body Mass Index (BMI) of 18.5 kg/m2 to 30 kg/m2, and weight ≥45 kg;
Key exclusion criteria (27 listed)
- Are pregnant or lactating;
- Have any one of the following medical conditions: uncontrolled diabetes mellitus, cancer other than skin cancer less than five years previously (e.g., basal-cell carcinoma (BCC) and squamous-cell carcinoma (SCC) of skin allowed), multiple sclerosis, seizure disorders, or other serious medical illness;
- Severe renal impairment (glomerular filtration rate (GFR) < 30 mL/min);
- Medical conditions which could interfere with muscle function such as infections, trauma, fractures, or planned surgery;
- Medical conditions that could affect hand functioning including but not limited to rheumatoid arthritis, Dupuytren's contracture, hand deformity, etc.;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Mexiletine granules for prolonged-release oral suspensionMexiletine PR | Drug | Mexiletine prolonged-release (PR) |
Primary outcome
To assess the long-term efficacy of once daily mexiletine PR for the symptomatic treatment of myotonia in patients with myotonic dystrophy type 1 and type 2 (DM1 and DM2) who have completed MEX-DM-302 study.
Time frame: 78 weeks
Handgrip relaxation time in DM1 patients by mean change in baseline of handgrip relaxation time (seconds) after maximal voluntary isometric contraction (MVIC)
27 secondary outcomes
To assess the long-term safety of once daily mexiletine PR for the symptomatic treatment of myotonia in patients with myotonic dystrophy type 1 and type 2 (DM1 and DM2) who have completed the MEX-DM-302 study
Time frame: 78 weeks
Mean change in VAS
Time frame: 78 weeks
Mean change in MBS scores
Time frame: 78 weeks
Mean change in health-related quality of life
Time frame: 78 weeks
Mean change in DM1-Activ-c scale (DM1 patients only)
Time frame: 78 weeks
Mean change in time to perform the 10-meter Walk Test
Time frame: 78 weeks
Mean change in handgrip relaxation time
Time frame: 78 weeks
Mean change in time to perform Timed-up and go (TUG) test
Time frame: 78 weeks
Mean change in health-related quality of life measured by EQ-5D
Time frame: 78 weeks
Mean change in Myotonic Dystrophy Health Index (MDHI) score (DM1 patients)
Time frame: 78 weeks
Mean change in Myotonic Dystrophy 2 Health Index (MD2HI) score (DM2 patients)
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by changes in ECG
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by changes in ECG (HR)
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by AEs
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (hematology measured in units of μL [microliters]) from change in baseline
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (hematology measured in units of % [percentage]) from change in baseline
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (hematology measured in g/dL [units of grams per deciliter]) from change in baseline
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (chemistry measured in units of mmol/L) from change in baseline
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (chemistry measured in units of U/L) from change in baseline
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (chemistry measured in units of g/dL) from change in baseline
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (chemistry measured in units of mg/dL) from change in baseline
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by standard clinical laboratory evaluations (urinalysis) from change in baseline
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by vital signs (pulse)
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by vital signs (body temperature)
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by vital signs (blood pressure)
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by vital signs (respiration)
Time frame: 78 weeks
Assess the long-term safety of mexiletine PR by physical examinations
Time frame: 78 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Jan 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
6 sites in 6 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Mexiletine granules for prolonged-release oral suspension in people with Myotonic Dystrophy, run by Lupin Ltd. at 6 sites in 6 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 27 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 26 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 6 sites in Belgium, Denmark, Germany, Italy, Spain and 1 more country. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
To assess the long-term efficacy of once daily mexiletine PR for the symptomatic treatment of myotonia in patients with myotonic dystrophy type 1 and type 2 (DM1 and DM2) who have completed MEX-DM-302 study. (time frame: 78 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Jan 2026.