Which treatment are the best to reduce myotonia?

Treatment of Myotonia - Lamotrigine versus Namuscla

Status

Active, not recruiting

Phases

Phase 3

Study type

Interventional

Source

EU CTR

Registry ID

EUCTR2021-003784-94-DK

Enrollment

Registered

2021-11-30

Start date

2022-01-20

Completion date

Unknown

Last updated

2025-02-17

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Myotonia Congenita (Becker and Thomsen type), Paramyotonia Congenita, and Hyperkalemic periodic paralysis MedDRA version: 20.1 Level: LLT Classification code 10049841 Term: Myotonia congenital System Organ Class: 100000004850 MedDRA version: 20.1 Level: LLT Classification code 10076440 Term: Hyperkalemic periodic paralysis System Organ Class: 100000004850

Interventions

Trade Name: Namuscla Pharmaceutical Form: Capsule, hard INN or Proposed INN: Mexiletine CAS Number: 31828-71-4 Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 167-

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1. Capable adult women and men (age = 18 years). 2. Diagnosed with Myotonia Congenita (Becker and Thomsen type), Paramyotonia Congenita, or Hyperkalemic periodic paralysis. 3. Myotonia under treatment or which significantly limits the daily activities (MBS> 2). Are the trial subjects under 18? no Number of subjects for this age range: F.1.2 Adults (18-64 years) yes F.1.2.1 Number of subjects for this age range 30 F.1.3 Elderly (>=65 years) yes F.1.3.1 Number of subjects for this age range 2

Exclusion criteria

Exclusion criteria: 1. Allergy to lamotrigine, mexiletine, or the inactive ingredients in trial medication. 2. Disease, which is affected by trial medication such as heart disease (ischemia and arrhythmia), epilepsy, and significant renal or hepatic failure. 3. Treatment that, in the opinion of the project manager, can affect the study result - medication with significant interactions with trial medication. 4. In case of smoking, start or cessation during the study. 5. Pregnant or breastfeeding during the study period. Fertile women with a positive pregnancy test at the time of entry into the trial, or who do not use safe contraception during the project period. The following contraceptives are considered safe: IUDs or hormonal contraceptives (birth control pills, implants, transdermal patches, vaginal ring or prolonged-release injections).

Design outcomes

Primary

Measure	Time frame
Main Objective: In patients with hereditary non-dystrophic myotonia, we want to investigate whether there is a treatment difference in efficacy and side effects of Namuscla vs. lamotrigine. The hypothesis is that the effect is equivalent to reduce the degree of myotonia. The study is a randomized, double-blind, non-inferiority, crossover study.;Secondary Objective: Not applicable;Primary end point(s): The primary end point is subjective assessment of myotonia on the Myotonia Behavior Scale (MBS). MBS is registered once a day for 6 separated weeks.;Timepoint(s) of evaluation of this end point: Week 4, 6+ and 7+ in both periods.	—

Measure

Time frame

Main Objective: In patients with hereditary non-dystrophic myotonia, we want to investigate whether there is a treatment difference in efficacy and side effects of Namuscla vs. lamotrigine. The hypothesis is that the effect is equivalent to reduce the degree of myotonia. The study is a randomized, double-blind, non-inferiority, crossover study.;Secondary Objective: Not applicable;Primary end point(s): The primary end point is subjective assessment of myotonia on the Myotonia Behavior Scale (MBS). MBS is registered once a day for 6 separated weeks.;Timepoint(s) of evaluation of this end point: Week 4, 6+ and 7+ in both periods.

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Secondary

Measure	Time frame
Secondary end point(s): 1) The 3 objective myotonitest a) Eye opening test (time in seconds): You pinch your eyes with maximum strength for five seconds, then open your eyes as soon as possible. Time is recorded from cessation of eye narrowing to complete eye opening. Is repeated 5 times. b) Hand opening test (time in seconds): You tie your hand with maximum strength for five seconds. Then open your hand as soon as possible. Time is recorded from the beginning of the movement until complete extension of all fingers. Is repeated 5 times. c) Mobility test – time-up&go (TUG) (time in seconds): First, you rest for at least 10 minutes in a chair with or without armrests, approximately 45-cm tall, then get up, walk 3 meters, turn around, go back, and sit down. You should perform this in your regular pace. Time is recorded from the beginning of the movement until the person sits in the chair again. The same chair is used throughout the study. 2) Questionnaire For people with neuromuscular disease a questionnaire has been prepared on quality of life and the impact of the disease on everyday life (INQoL)(19). The form is translated in Danish and has been validated for channelopathies. It will be filled in at inclusion, during placebo and after both treatment periods. 3) Side effects The trial participants record all adverse events, side effects and nuisances that may occur while taking experimental medication. Subsequently, we will determine whether the listed side effects are known according to the product summary, and can be related to the treatment period with lamotrigine or Namuscla, respectively. Side effects are recorded daily. You can choose between none, tick alphabetically lists containing the known side effects for both preparations, or you can note the side effect under other. In the same periods where MBS is assessed, a side effect scale (SES), similar to the MBS, is filled in. ;Timepoint(s) of evaluation of this end point: 1) Myotonia test: the last day of we	—

Measure

Time frame

Secondary end point(s): 1) The 3 objective myotonitest a) Eye opening test (time in seconds): You pinch your eyes with maximum strength for five seconds, then open your eyes as soon as possible. Time is recorded from cessation of eye narrowing to complete eye opening. Is repeated 5 times. b) Hand opening test (time in seconds): You tie your hand with maximum strength for five seconds. Then open your hand as soon as possible. Time is recorded from the beginning of the movement until complete extension of all fingers. Is repeated 5 times. c) Mobility test – time-up&go (TUG) (time in seconds): First, you rest for at least 10 minutes in a chair with or without armrests, approximately 45-cm tall, then get up, walk 3 meters, turn around, go back, and sit down. You should perform this in your regular pace. Time is recorded from the beginning of the movement until the person sits in the chair again. The same chair is used throughout the study. 2) Questionnaire For people with neuromuscular disease a questionnaire has been prepared on quality of life and the impact of the disease on everyday life (INQoL)(19). The form is translated in Danish and has been validated for channelopathies. It will be filled in at inclusion, during placebo and after both treatment periods. 3) Side effects The trial participants record all adverse events, side effects and nuisances that may occur while taking experimental medication. Subsequently, we will determine whether the listed side effects are known according to the product summary, and can be related to the treatment period with lamotrigine or Namuscla, respectively. Side effects are recorded daily. You can choose between none, tick alphabetically lists containing the known side effects for both preparations, or you can note the side effect under other. In the same periods where MBS is assessed, a side effect scale (SES), similar to the MBS, is filled in. ;Timepoint(s) of evaluation of this end point: 1) Myotonia test: the last day of we

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Countries

Denmark

Contacts

Public ContactMD

Rigshospitalet, department of Neurology

grete.andersen.01@regionh.dk

Outcome results

None listed

Source: EU CTR (via WHO ICTRP) · Data processed: Feb 4, 2026