Prospective, Long Term, Observational Study (Patient Registry) of Paediatric Myotonic Disorders

NCT07154654 | Recruiting

• 1 other identifier: MEX-NM-401
• Study Type: observational
• Target: 10
• Locations: 1 country
• Sites: 1

Brief Summary

This is a prospective, open-label, multi-centre, single arm, registry study to collect standard relevant clinical and epidemiological data during routine medical evaluation and treatment in paediatric patients with myotonic disorders who are being treated with mexiletine therapy according to the physician.

Conditions

Myotonic Disorders

Outcome Measures

Primary Outcomes (1)

• To assess long-term safety by collection of SAEs, AEs, AESIs, changes in frequency, treatment interruptions

  Number and frequency of adverse events (AEs), serious adverse events (SAEs) and AE leading to treatment discontinuation, throughout the study while on treatment with mexiletine; Incidence of adverse events of special interest (AESI), namely: Severe Cutaneous Adverse Reactions (SCARs) \& Cardiac arrhythmia. Increased frequency of seizure episodes in patients with epilepsy; Any changes in frequency, treatment interruptions of mexiletine

  Baseline to 24 months

Secondary Outcomes (4)

• To assess the suitability of mexiletine administration

  Baseline to 24 months

• To understand how mexiletine is used by clinicians

  Baseline to 24 months

• Description over time of outcomes of mexiletine use

  Baseline to 24 months

• The treating physician with elaborate a brief text with risk-benefit conclusions

  Baseline to 24 months

Other Outcomes (2)

• Description over time of any efficacy outcomes

  Baseline to 24 months

• Clinical Global Impression (CGI) Scores

  Baseline to 24 months

Study Arms (2)

Cohort 1

Infants and children aged between 6 months to less than 6 years.

Drug: Mexiletine

Cohort 2

Neonates and infants from birth to less than 6 months.

Drug: Mexiletine

Interventions

Mexiletine DRUG

Non interventional

Cohort 1; Cohort 2

Eligibility Criteria

• Age: Up to 6 Years
• Sex: all
• Age Groups: Child (0-17)
• Sampling Method: Probability Sample

Study Population

The study population will include male and female children from birth to less than 6 years of age with clinical symptoms or signs of myotonic disorders, normal electrocardiogram (ECG) exam and genetic confirmation of the diagnosis i.e., non-dystrophic myotonia (NDM), or myotonic dystrophy (DM) type 1 (DM1), or DM type 2 (DM2), and who comply with the inclusion / exclusion criteria. Patients will be enrolled consecutively at each site in order to minimize selection bias

You may qualify if:

• Male or female patients from birth to less than 6 years
• A genetically confirmed diagnosis of NDM or DM (DM1or DM2), as per the treating clinician.
• Presence of clinical symptoms of myotonia (hand grip myotonia, myotonia in the leg muscles, any other myotonia symptoms) to be confirmed by the treating clinician.
• Patients already receiving mexiletine treatment or who are clinically considered for mexiletine treatment as per the treating physician judgement.
• No history of or significant cardiac abnormalities as determined by a cardiologist's assessment of the ECG and echocardiogram performed prior to enrolment in the study or as per the treating physician standard of care (NaMuscla SmPC, 2023)
• No known history or signs and symptoms of any significant liver disorder as per treating physician.
• No known clinically relevant abnormal laboratory investigations for haematology, biochemistry, and urinalysis values at screening (or based on values obtained within 3 months prior to screening in patient's medical record) that could affect the study objectives as judged by the treating physician.
• Parent or legal guardian able to provide consent/assent to study participation and to sign the written informed consent or non-opposition as per local regulatory requirements prior to study entry and perform any study-related activity. -

You may not qualify if:

• Any contraindication to mexiletine as listed in the Namuscla Summary of Product Characteristics (SmPC) (NaMuscla SmPC, 2023)
• Hypersensitivity to the active substance, or to any of the excipients
• Hypersensitivity to any local anaesthetic
• Ventricular tachyarrhythmia
• Complete heart block (i.e., third-degree atrioventricular block) or any heart block susceptible to evolve to complete heart block (first-degree atrioventricular block with markedly prolonged PR interval (≥ 200 ms) and/or wide QRS complex (≥ 120 ms), second-degree atrioventricular block, bundle branch block, bifascicular and trifascicular block),
• QT interval \> 450ms
• Myocardial infarction (acute or past), or abnormal Q-waves
• Symptomatic coronary artery disease
• Heart failure with ejection fraction \<50%
• Atrial tachyarrhythmia, fibrillation or flutter
• Sinus node dysfunction (including sinus rate \< 50 bpm)
• Co-administration with medicinal products inducing torsades de pointes.
• Co-administration with medicinal products with narrow therapeutic index
• Any other neurological or psychiatric condition that might affect the study assessments, as per the treating clinician.
• Any clinically significant illness, laboratory findings, ECG, or other clinical symptoms, which in the opinion of the treating physician could affect the patient's optimal participation in the study

Sponsors & Collaborators

• Lupin Ltd.: lead

Study Sites (1)

Centre Hospitalier Universitaire de Clermont-Ferrand

Clermont-Ferrand, France

RECRUITING

MeSH Terms

Conditions

Myotonic Disorders

Interventions

Mexiletine

Condition Hierarchy (Ancestors)

Muscular Diseases; Musculoskeletal Diseases; Neuromuscular Diseases; Nervous System Diseases

Intervention Hierarchy (Ancestors)

Propylamines; Amines; Organic Chemicals; Phenyl Ethers; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons

Study Officials

• Catharine Sarret, MD

  University Hospital, Clermont-Ferrand

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Nikki Adetoro

CONTACT

4434474534; nikkiadetoro@lupin.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 2 Years
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 24, 2025
• First Posted: September 4, 2025
• Study Start: September 30, 2025
• Primary Completion (Estimated): November 22, 2027
• Study Completion (Estimated): February 22, 2028
• Last Updated: September 23, 2025

Record last verified: 2025-09

Locations

FR (1)