Actively Recruiting
Open-Label, Randomized, Cross-Over Study Comparing Mexiletine Prolonged-Release and Immediate-Release in Non-Dystrophic Myotonias (ACHILLES Study)
Led by Lupin Ltd. · Updated on 2025-12-22
24
Participants Needed
1
Research Sites
4 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
This research investigates the safety and effectiveness of two forms of mexiletine—prolonged-release (PR) and immediate-release (IR)—in patients with non-dystrophic myotonias, including myotonia congenita, paramyotonia congenita, and sodium channel myotonia. This multicenter, open-label, randomized, cross-over study aims to compare these forms to better understand their effects on this condition. The study plans to enroll 24 patients, split evenly between those who are new to mexiletine treatment and those with previous treatment experience. Participants will undergo a 4-week screening followed by two 12-week treatment periods. Initially, patients will be randomly assigned to receive either mexiletine PR once daily or mexiletine IR three times daily. After a washout period of at least 7 days, they will switch to the other treatment for another 12 weeks. Different doses of mexiletine PR (167 mg, 333 mg, or 500 mg) and mexiletine IR (167 mg) are used to assess safety and efficacy. Throughout the study, participants will be closely monitored through patient and physician reports of adverse events, electrocardiograms (ECGs), laboratory tests, physical exams, and vital signs. Efficacy will be measured using patient-reported outcomes and functional tests such as handgrip relaxation time, timed walking tests, and quality of life assessments. The main safety comparisons include heart rhythm intervals and rates, with observations continuing from baseline through week 24.
CONDITIONS
Brief Title
An Open-Label, Randomized, Cross-Over Study to Investigate the Efficacy and Safety of Mexiletine PR Compared to Mexiletine IR
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Able and willing to sign informed consent or assent (if under 18) with parental/guardian permission
- Confirmed genetic diagnosis of non-dystrophic myotonias including myotonia congenita, paramyotonia congenita, or sodium channel myotonia
- 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
- Female participants of childbearing potential must use effective birth control during and for 30 days after the study; males must also use birth control during and for 30 days after the study
- No significant cardiac abnormalities based on ECG and echocardiogram within 3 months before study start
- Myotonic symptoms severe enough to need treatment as judged by the investigator
- Clinical handgrip myotonia of 3 seconds or more at screening (for treatment-naive) and on Day 1 (for all participants)
You will not qualify if you...
- Pregnant or breastfeeding
- Uncontrolled diabetes, recent cancer (other than certain skin cancers), multiple sclerosis, seizure disorders, or other serious illnesses that prevent study participation
- 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, Dupuytren's contracture, or hand deformities
- Severe arthritis or other conditions that significantly limit walking
- Severe liver impairment or elevated liver tests more than 3 times normal
- Electrolyte imbalances including low or high potassium or magnesium levels
- Use of other anti-myotonic drugs within 4 weeks before baseline
- Use of medications that increase cardiac risk or adverse reactions
- Allergy to mexiletine or related substances
- Participation in another interventional study within 3 months
- Wheelchair-bound or bedridden
- Any cardiac safety issues found during screening
- Current smokers within one month before screening
- Prior mexiletine treatment within 1 week before baseline for previously treated subgroup; treatment-naive subgroup excludes prior mexiletine use
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)
Duration - 12 weeks per treatment period
Participants receive mexiletine prolonged-release or immediate-release to evaluate efficacy and safety in a randomized, cross-over design.
2 treatment periods of 12 weeks each with a washout period of at least 7 days in between
Trial Site Locations
Total: 1 location
1
Universitair Ziekenhuis Leuven"UZ Leuven Gasthuisberg Campus Herestraat 49 Leuven, 3000"
Leuven, Belgium
Actively Recruiting
Research Team
N
Nikki Adetoro
How is the study designed?
Study Type
INTERVENTIONAL
Masking
SINGLE
Allocation
RANDOMIZED
Model
CROSSOVER
Primary Purpose
TREATMENT
Number of Arms
2
Frequently Asked Questions
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