MyotoniaPhase 3NCT07097701
An Open-Label, Randomized, Cross-Over Study to Investigate the Efficacy and Safety of Mexiletine PR Compared to Mexiletine IR
A Phase 3 study testing Granular powder in unit dose foil-lined sachet Mexiletine (PR) and Oral Capsule Mexiletine (IR) in people with Myotonia, run by Lupin Ltd. at 1 site in Belgium.
Trial summary
An Open-Label, Randomized, Cross-Over Study to Investigate the Efficacy and Safety of Mexiletine PR compared to Mexiletine IR in Patients with Non-Dystrophic Myotonias (ACHILLES study) Read more about this study
- Who is it for?
- Ages 16 years and older
- Conditions the study is for
- Myotonia
- What is being tested?
- Granular powder in unit dose foil-lined sachet Mexiletine (PR) and Oral Capsule Mexiletine (IR)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 24 participants
- Where
- 1 siteBelgium
- Study dates
- 3 Sep 2025to 22 Feb 2027
- 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
- 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);
- Non-dystrophic myotonias including myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM) confirmed genetically;
- Male or non-pregnant female ≥16 years and older at screening;
- 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 30 days after last dose of study drug. Male patients must use birth control for the duration of the study and for at least 30 days after last dose of study drug;
- No significant cardiac abnormalities as determined by a cardiologist including electrocardiogram (ECG) and echocardiogram not older than 3 months prior to study entry;
- Participants with myotonic symptoms severe enough to justify treatment (in the opinion of the study investigator);
- Presence of clinical handgrip myotonia (delayed relaxation of grip of ≥ 3 second using a stopwatch) at screening (naïve patients only) and on Day 1 (pre-dose) (patients naïve and previously treated with mexiletine).
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 or has any other condition, which in the opinion of the Investigator, precludes the participant's participation in the study or the participant is unlikely to comply with the protocol-defined procedures and therefore is unlikely to complete the study;
- 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 than NDM) that would significantly impact ambulation;
Show all 16Show fewer
- Severe hepatic impairment or preexisting elevated liver function tests > 3 times the upper limit of normal (ULN) at screening (alanine transaminase (ALT)/aspartate transaminase (AST), gamma-glutamyl transferase (GGT)) and/or any abnormal chemistry, hematology or urine lab considered clinically significant by the 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 hypocalcaemia, hypercalcaemia, 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 other anti-myotonic treatment within 4 weeks prior to baseline (Day 1) or 5 half-lives, whichever is longer (e.g., metformin, propafenone, flecainide, lamotrigine, carbamazepine or any other channel-blocker/anticonvulsive drugs;
- Use of any concomitant medications that could increase the cardiac risk or increases the risk of adverse reactions (see Section 6.8 for a complete list of prohibited concomitant medications);
- Known allergy to mexiletine or any of the excipients 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;
- Wheelchair-bound or bedridden;
- Any cardiac safety-associated condition including any of the following criteria detected by screening cardiac evaluations including ECG, echocardiogram and clinical evaluations (see protocol Section 5.3 for a detailed list);
- Current smokers (within one month of the screening visit) (eg, cigarettes, cigars, vape/e-cigarette products, etc.);
- Subgroup 'mexiletine-naïve': patients with previous treatment with mexiletine are excluded. Subgroup 'previous mexiletine treatment': patients with treatment with mexiletine within 1 week prior to baseline (Day 1) are excluded
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Belgium1 site, 1 recruiting
- Recruiting
Universitair Ziekenhuis Leuven"UZ Leuven Gasthuisberg Campus Herestraat 49 Leuven, 3000"
Leuven
Kristi Claeys
Kristi Claeys
About this study
Official title: An Open-Label, Randomized, Cross-Over Study to Investigate the Efficacy and Safety of Mexiletine PR Compared to Mexiletine IR in Patients With Non-Dystrophic Myotonias (ACHILLES Study)
An Open-Label, Randomized, Cross-Over Study to Investigate the Efficacy and Safety of Mexiletine PR compared to Mexiletine IR in Patients with Non-Dystrophic Myotonias (ACHILLES study)
Read the detailed description
This is a multicenter, open-label, randomized, cross-over study intended to evaluate the efficacy and the safety of mexiletine PR (QD) vs mexiletine IR (TID) in patients with non-dystrophic myotonias including myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM). The study will consist of a 4-week screening period followed by two 12-week treatment periods. Eligible patients will be randomized to receive mexiletine PR or mexiletine IR for 12 weeks. After a wash out period of at least 7 days the patients will receive the opposite treatment for 12 weeks.
A total of 24 patients are planned to be enrolled (with a target enrollment of 12 naïve to previous mexiletine treatment and 12 previously treated with mexiletine).
Safety assessments include patient- and physician-reported adverse event reporting, electrocardiogram (ECG), standard clinical laboratory evaluations, physical examinations, and vital signs. Efficacy assessments include patient-reported outcomes (PROs) and functional capacity outcome measures.
- Conditions
- Myotonia
- Being tested
- Granular powder in unit dose foil-lined sachet Mexiletine (PR), Oral Capsule Mexiletine (IR)
- Medical subject headings
- Myotonia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Granular powder in unit dose foil-lined sachet Mexiletine (PR)Drug
Mexiletine (PR)
Oral Capsule Mexiletine (IR)Drug
Mexiletine (IR)
| Study group | Role | What they receive |
|---|---|---|
| Mexiletine prolonged-release (PR) | Active comparator | 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: Granular powder in unit dose foil-lined sachet Mexiletine (PR) |
| Mexiletine immediate release (IR) | Active comparator | Mexiletine IR 167 mg (mexiletine HCl 200 mg) Receives: Drug: Oral Capsule Mexiletine (IR) |
What is being measured
The primary outcome is the main question the study is designed to answer.
To compare the safety of mexiletine PR vs mexiletine IR by incidence of treatment emergent Adverse Events (TEAEs), treatment-related TEAEs, serious AEs, and patient discontinuation rate between mexiletine PR and mexiletine IR after 12 weeks of treatment.
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by incidence of treatment emergent Adverse Events (TEAEs), treatment-related TEAEs, serious AEs, and patient discontinuation rate between mexiletine PR and mexiletine IR after 12 weeks of treatment.
Measured: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR by mean change from baseline in QTc intervals by12-lead in ECG
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by mean change from baseline in QTc Intervals by12-lead in ECG
Measured: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR by mean change from baseline in PR intervals by12-lead in ECG
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by mean change from baseline in PR intervals by12-lead in ECG.
Measured: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR by mean change from baseline in QRS intervals by12-lead in ECG
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by mean change from baseline in QRS intervals by12-lead in ECG
Measured: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR by mean change from baseline by average minimum heart rate by12-lead in ECG
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by mean change from baseline in average heart rate by 12-lead in ECG
Measured: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR by performing physical examiniations
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by performing physical examinations. The investigator will complete a physical examination including the following regions and systems: general appearance, head and neck, heart, lung, abdomen, chest and back, upper extremities, lower extremities, neurological, and dermatological. In addition, height and weight will be recorded.
Measured: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR by assessing vital signs
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by assessing vital signs. Vital signs will be obtained at each study visit and will include pulse, respiration, body temperature, and blood pressure. Unscheduled vital sign measurements may be obtained at the investigator's discretion during the study.
Measured: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR by performing standard clinical laboratory evaluations
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by performing standard clinical laboratory evaluations. Clinical laboratory samples will be collected under fasting conditions and hematology, serum chemistry, and urinalysis assessments will be performed
Measured: Baseline to week 24
Secondary outcomes (12)
Mean change in handgrip relaxation time
Opening Time (VHOT) functional evaluation by mean change in maximal voluntary isometric contraction (MVIC) and relaxation time by Video-recording of Hand. The dominant wrist and hand are placed on a bedside table with the forearm fully supinated. The patient is asked to open the hand after making a tight fist for 3-5 seconds 2 times within 30 minutes.
Measured: Baseline to week 24
Mean change in health-related quality of life
Mean change in health-related quality of life (measured by INQoL) on a 7-point Likert scale
Measured: Baseline to week 24
Mean change in MBS scores
Mean change in Myotonia Behavior Scale (MBS) scores on a 0-5 rating scale
Measured: Baseline to week 24
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: Baseline to week 24
Mean change in VAS
Score for muscle stiffness (myotonia severity) as self-reported by patients on a Visual Analog Scale (VAS) on a 1-100 rating scale.
Measured: Baseline to week 24
Mean change in Clinical Global Impression (CGI) - Efficacy Scale
Score for Clinical Global Impression (CGI) - Efficacy by a 5 rating scale of No Symptoms to Very Severe
Measured: Baseline to week 24
Mean change in Clinical Global Impression (CGI) - Tolerability Index Scale
Mean change in Clinical Global Impression (CGI) - Tolerability Index Scale by a 7 rating scale of much worse to much better
Measured: Baseline to week 24
Mean change in time to perform the 10-meter Walk Test
Mean change in time (seconds) to perform the 10-meter Walk Test (10mWT) 10mWT is a performance-based test assessing walking in two different conditions, own preferred speed and maximum speed, over a short distance. The time taken to walk 10 meters at usual comfortable and maximum speed is recorded with a stopwatch.
Measured: Baseline to week 24
Mean change in Gastrointestinal function: The Gastroesophageal Reflux Disease-Health Related Quality of Life (GERD-HRQoL)
Mean change in Gastrointestinal function: The Gastroesophageal Reflux Disease-Health Related Quality of Life (GERD-HRQoL) by a 5 scale of no symptoms to Symptoms are incapacitating, unable to do daily activities
Measured: Baseline to week 24
Mean change in CMRS Scale
Mean change in Clinical myotonia rating scale (CMRS)
Measured: Baseline to week 24
Mean change Swallowing function
Mean change in Swallowing function: timed testing of swallowing
Measured: Baseline to week 24
Preference between the two study treatments
Patients were also asked to give their preference between the 2 periods of treatment and to provide the primary reasons for their choice.
Measured: Baseline to week 24
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Jul 2025
- Study start3 Sep 2025
- Primary completion22 Jan 2027 (estimated)
- Study completion22 Feb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for MyotoniaStudies 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
- Randomised
- Intervention model
- Crossover
- Model description
- This is a multicenter, open-label, randomized, cross-over study intended to evaluate the efficacy and the safety of mexiletine PR (QD) vs mexiletine IR (TID) in patients with non-dystrophic myotonias including myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM). The study will consist of a 4-week screening period followed by two 12-week treatment periods. Eligible patients will be randomized to receive mexiletine PR or mexiletine IR for 12 weeks. After a wash out period of at least 7 days the patients will receive the opposite treatment for 12 weeks. A total of 24 patients are planned to be enrolled (with a target enrollment of 12 naïve to previous mexiletine treatment and 12 previously treated with mexiletine).
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 24 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
- NCT07097701
- Sponsor's protocol ID
- MEX-NDM-301
- Status last verified
- Dec 2025
- First submitted
- 21 Nov 2024
- Last updated
- 22 Dec 2025
- 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 22 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-Label, Randomized, Cross-Over Study to Investigate the Efficacy and Safety of Mexiletine PR Compared to Mexiletine IR in Patients With Non-Dystrophic Myotonias (ACHILLES Study)
- ClinicalTrials.gov ID
- NCT07097701
- Acronym / sponsor ID
- MEX-NDM-301
- Conditions
- Myotonia
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 24 participants (estimated)
- Lead sponsor
- Lupin Ltd.Industry (pharma, biotech, devices)
- Collaborators
- Lupin Atlantis Holdings S.A.
- Study start
- 3 Sep 2025 (actual)
- Primary completion
- 22 Jan 2027 (estimated)
- Study completion
- 22 Feb 2027 (estimated)
- First posted
- 31 Jul 2025 (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.
An Open-Label, Randomized, Cross-Over Study to Investigate the Efficacy and Safety of Mexiletine PR compared to Mexiletine IR in Patients with Non-Dystrophic Myotonias (ACHILLES study)
Detailed description
This is a multicenter, open-label, randomized, cross-over study intended to evaluate the efficacy and the safety of mexiletine PR (QD) vs mexiletine IR (TID) in patients with non-dystrophic myotonias including myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM). The study will consist of a 4-week screening period followed by two 12-week treatment periods. Eligible patients will be randomized to receive mexiletine PR or mexiletine IR for 12 weeks. After a wash out period of at least 7 days the patients will receive the opposite treatment for 12 weeks.
A total of 24 patients are planned to be enrolled (with a target enrollment of 12 naïve to previous mexiletine treatment and 12 previously treated with mexiletine).
Safety assessments include patient- and physician-reported adverse event reporting, electrocardiogram (ECG), standard clinical laboratory evaluations, physical examinations, and vital signs. Efficacy assessments include patient-reported outcomes (PROs) and functional capacity outcome measures.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- This is a multicenter, open-label, randomized, cross-over study intended to evaluate the efficacy and the safety of mexiletine PR (QD) vs mexiletine IR (TID) in patients with non-dystrophic myotonias including myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM). The study will consist of a 4-week screening period followed by two 12-week treatment periods. Eligible patients will be randomized to receive mexiletine PR or mexiletine IR for 12 weeks. After a wash out period of at least 7 days the patients will receive the opposite treatment for 12 weeks. A total of 24 patients are planned to be enrolled (with a target enrollment of 12 naïve to previous mexiletine treatment and 12 previously treated with mexiletine).
| Arm | Type | Receives |
|---|---|---|
| Mexiletine prolonged-release (PR) | Active comparator | Drug: Granular powder in unit dose foil-lined sachet Mexiletine (PR)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) |
| Mexiletine immediate release (IR) | Active comparator | Drug: Oral Capsule Mexiletine (IR)Mexiletine IR 167 mg (mexiletine HCl 200 mg) |
Who may qualify
- Ages
- 16 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (8 listed)
- 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);
- Non-dystrophic myotonias including myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM) confirmed genetically;
- Male or non-pregnant female ≥16 years and older at screening;
- 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 30 days after last dose of study drug. Male patients must use birth control for the duration of the study and for at least 30 days after last dose of study drug;
Key exclusion criteria (16 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 or has any other condition, which in the opinion of the Investigator, precludes the participant's participation in the study or the participant is unlikely to comply with the protocol-defined procedures and therefore is unlikely to complete the study;
- 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 |
|---|---|---|
| Granular powder in unit dose foil-lined sachet Mexiletine (PR)Mexiletine (PR) | Drug | Mexiletine prolonged-release (PR) |
| Oral Capsule Mexiletine (IR)Mexiletine (IR) | Drug | Mexiletine immediate release (IR) |
Primary outcome
To compare the safety of mexiletine PR vs mexiletine IR by incidence of treatment emergent Adverse Events (TEAEs), treatment-related TEAEs, serious AEs, and patient discontinuation rate between mexiletine PR and mexiletine IR after 12 weeks of treatment.
Time frame: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by incidence of treatment emergent Adverse Events (TEAEs), treatment-related TEAEs, serious AEs, and patient discontinuation rate between mexiletine PR and mexiletine IR after 12 weeks of treatment.
To compare the safety of mexiletine PR vs mexiletine IR by mean change from baseline in QTc intervals by12-lead in ECG
Time frame: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by mean change from baseline in QTc Intervals by12-lead in ECG
To compare the safety of mexiletine PR vs mexiletine IR by mean change from baseline in PR intervals by12-lead in ECG
Time frame: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by mean change from baseline in PR intervals by12-lead in ECG.
To compare the safety of mexiletine PR vs mexiletine IR by mean change from baseline in QRS intervals by12-lead in ECG
Time frame: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by mean change from baseline in QRS intervals by12-lead in ECG
To compare the safety of mexiletine PR vs mexiletine IR by mean change from baseline by average minimum heart rate by12-lead in ECG
Time frame: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by mean change from baseline in average heart rate by 12-lead in ECG
To compare the safety of mexiletine PR vs mexiletine IR by performing physical examiniations
Time frame: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by performing physical examinations. The investigator will complete a physical examination including the following regions and systems: general appearance, head and neck, heart, lung, abdomen, chest and back, upper extremities, lower extremities, neurological, and dermatological. In addition, height and weight will be recorded.
To compare the safety of mexiletine PR vs mexiletine IR by assessing vital signs
Time frame: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by assessing vital signs. Vital signs will be obtained at each study visit and will include pulse, respiration, body temperature, and blood pressure. Unscheduled vital sign measurements may be obtained at the investigator's discretion during the study.
To compare the safety of mexiletine PR vs mexiletine IR by performing standard clinical laboratory evaluations
Time frame: Baseline to week 24
To compare the safety of mexiletine PR vs mexiletine IR for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonias (myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonia (SCM)) by performing standard clinical laboratory evaluations. Clinical laboratory samples will be collected under fasting conditions and hematology, serum chemistry, and urinalysis assessments will be performed
12 secondary outcomes
Mean change in handgrip relaxation time
Time frame: Baseline to week 24
Mean change in health-related quality of life
Time frame: Baseline to week 24
Mean change in MBS scores
Time frame: Baseline to week 24
Mean change in time to perform Timed-up and go (TUG) test
Time frame: Baseline to week 24
Mean change in VAS
Time frame: Baseline to week 24
Mean change in Clinical Global Impression (CGI) - Efficacy Scale
Time frame: Baseline to week 24
Mean change in Clinical Global Impression (CGI) - Tolerability Index Scale
Time frame: Baseline to week 24
Mean change in time to perform the 10-meter Walk Test
Time frame: Baseline to week 24
Mean change in Gastrointestinal function: The Gastroesophageal Reflux Disease-Health Related Quality of Life (GERD-HRQoL)
Time frame: Baseline to week 24
Mean change in CMRS Scale
Time frame: Baseline to week 24
Mean change Swallowing function
Time frame: Baseline to week 24
Preference between the two study treatments
Time frame: Baseline to week 24
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 22 Dec 2025.
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Granular powder in unit dose foil-lined sachet Mexiletine (PR) and Oral Capsule Mexiletine (IR) in people with Myotonia, run by Lupin Ltd. at 1 site in Belgium.
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 8 inclusion and 16 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: looking for participants now, as of the sponsor's last update on 22 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. 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?
Contact Nikki Adetoro (4434474534, nikkiadetoro@lupin.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
To compare the safety of mexiletine PR vs mexiletine IR by incidence of treatment emergent Adverse Events (TEAEs), treatment-related TEAEs, serious AEs, and patient discontinuation rate between mexiletine PR and mexiletine IR after 12 weeks of treatment. (time frame: Baseline to week 24). The study lists 8 primary outcomes in all. 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 22 Dec 2025.