Actively Recruiting
A Randomized, Double-Blind, Placebo-Controlled, Multi-Center Study to Investigate the Efficacy and Safety of Once Daily Mexiletine PR During 26 Weeks of Treatment in Patients With Myotonic Dystrophy Type 1 and Type 2 (Phase 3)
Led by Lupin Ltd. · Updated on 2026-02-06
176
Participants Needed
7
Research Sites
5 weeks
Total Duration
On this page
Sponsors
L
Lupin Ltd.
Lead Sponsor
L
Lupin Atlantis Holdings S.A.
Collaborating Sponsor
AI-Summary
What this Trial Is About
Researchers are evaluating the safety and effectiveness of once daily mexiletine prolonged-release (PR) in treating myotonic dystrophy type 1 and type 2 (DM1 and DM2). This multicenter, randomized, double-blind, placebo-controlled study includes approximately 80 DM1 patients and 16 DM2 patients. The purpose is to assess mexiletine PR's impact on symptoms related to myotonia, compared to placebo, over a 26-week treatment period. Participants will undergo a 4-week screening followed by random assignment to receive either mexiletine PR or a matching placebo. The mexiletine doses include 167 mg, 333 mg, or 500 mg, administered once daily. Patient visits are scheduled at screening, baseline, and at Weeks 1, 2, 14, and 26. An interim analysis will be conducted after 40 patients complete or terminate the study early. During the study, participants will complete assessments including handgrip myotonia tests, walking ability, quality of life measures, and muscle function scales. Safety will be monitored through ECGs, laboratory tests, vital signs, and physical exams. Researchers will also study the pharmacokinetics of mexiletine PR. The total participation duration is about 30 weeks, including screening and treatment.
CONDITIONS
Brief Title
The Efficacy and Safety of Once Daily Mexiletine PR in Patients With Myotonic Dystrophy Type 1 and Type 2
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Genetically confirmed diagnosis of myotonic dystrophy type 1 or type 2 (DM1 or DM2)
- Ability to understand and sign informed consent (or parental consent and patient assent if under 18 years old)
- Willingness and ability to stay in the study for the full 26-week treatment period
- Male or non-pregnant female aged 16 years or older
- Body Mass Index between 18.5 and 30 kg/m2, and weight at least 45 kg
- Females of childbearing potential must use highly effective birth control during the study and for at least 7 days after last dose
- No significant cardiac abnormalities as assessed by a cardiologist
- Sufficient finger flexor strength to grasp the device handle for myotonia testing
- Clinical handgrip myotonia with delayed relaxation of 3 seconds or more at screening
- Able to walk independently 10 meters (using cane, walker, or orthoses if needed)
- For DM1 patients only: Muscular Impairment Rating Scale score of 2, 3, or 4
You will not qualify if you...
- Pregnant or breastfeeding
- Uncontrolled diabetes mellitus or serious medical illnesses such as multiple sclerosis or seizure disorders
- Cancer other than certain skin cancers within the past 5 years
- Severe kidney impairment (GFR below 30 mL/min)
- Medical conditions affecting muscle function like infections, trauma, fractures, or planned surgery
- Conditions affecting hand function such as rheumatoid arthritis or hand deformities
- Severe arthritis or other conditions impacting walking ability
- History of more than 5 falls in the past year
- Elevated liver function tests over 3 times the normal limit or other significant lab abnormalities
- Electrolyte imbalances (potassium or magnesium levels outside normal ranges)
- Use of mexiletine or anti-myotonic drugs within 4 weeks prior to study start
- Use of medications that increase cardiac risk
- Allergy to mexiletine or local anesthetics
- Participation in another interventional trial within the past 3 months
- Wheelchair-bound or bedridden
- Various cardiac safety issues including certain heart blocks, arrhythmias, heart failure, and implanted defibrillators or pacemakers
- Presence of symptomatic coronary artery disease
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person) at screening
Duration - 26 weeks
Participants receive once daily mexiletine PR or placebo for the symptomatic treatment of myotonia in myotonic dystrophy type 1 and type 2.
Visits at baseline, Weeks 1, 2, 14, and 26 (5 visits total)
Trial Site Locations
Total: 7 locations
1
Laboratory for Muscle Diseases and Neuropathies
Leuven, Belgium
Actively Recruiting
2
Aarhus University Hospital
Aarhus, Denmark
Actively Recruiting
3
Ludug-Maximilians University
München, Germany
Actively Recruiting
4
Azienda Ospedaliera Universitaria Policlinico Tor Vergata
Rome, Italy
Actively Recruiting
5
University Hospital of Madrid
Madrid, Spain
Actively Recruiting
6
Saint George's University Hospitals NHS Foundation Trust
London, United Kingdom
Actively Recruiting
7
University College Hospital
London, United Kingdom
Actively Recruiting
Research Team
N
Nikki Adetoro
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
RANDOMIZED
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
2
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