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New study reveals lamotrigine as a promising treatment for non-dystrophic myotonia, offering effective relief with fewer side effects.
Researchers at University College London (UCL) have made significant strides in the treatment of non-dystrophic myotonia, a rare genetic neuromuscular disorder, by demonstrating that lamotrigine—a drug commonly used to manage epilepsy and mood disorders—is as effective as mexiletine in alleviating symptoms. The findings, published in Lancet Neurology, suggest that lamotrigine could become a crucial alternative therapy for patients suffering from this debilitating condition.
Study Overview
The study conducted a pioneering head-to-head trial comparing the effectiveness of lamotrigine and mexiletine in 60 adults diagnosed with non-dystrophic myotonia. Participants were randomly assigned to receive either drug for eight weeks, followed by a crossover to the other treatment after a one-week washout period, ensuring a blind trial where neither the patients nor the researchers knew which drug was being administered at any time.
Results indicated that lamotrigine reduced muscle stiffness—the primary symptom of non-dystrophic myotonia—by a similar degree to mexiletine. This finding is particularly significant as it presents a well-tolerated option for patients, with no serious side effects reported during the trial.
The Challenge of Rare Diseases
Dr. Vino Vivekanandam, the chief investigator and consultant neurologist at UCL Queen Square Institute of Neurology, highlighted the challenges faced by individuals with rare diseases. “Approximately one in 17 people in the UK have a rare disease, with many having no available treatment. Non-dystrophic myotonia causes life-changing symptoms that significantly affect patients’ quality of life and employability,” he explained.
Previously, mexiletine was established as the first-line treatment for this condition after a 2012 UCL-led trial, but not all patients benefitted, and one-third experienced adverse gastrointestinal effects. Furthermore, mexiletine cannot be prescribed during pregnancy, when symptoms often intensify.
Lamotrigine: A Viable Alternative
Lamotrigine emerges as a safer and more accessible alternative. The trial confirmed that it is well tolerated, can be used during pregnancy, and is typically less expensive. The study findings could reshape clinical practice globally, especially in developing countries where mexiletine may be hard to obtain or cost-prohibitive.
Professor Michael Hanna, the senior author and director at UCL Queen Square Institute of Neurology, emphasized the importance of drug repurposing for rare diseases. “This research not only identifies lamotrigine as a comparable treatment but also provides more real-world options for affected patients,” he said.
Dr. Vivekanandam has already developed a personalized treatment algorithm based on the trial data, which is now being utilized in clinical practice. This algorithm incorporates various trial considerations, the mechanisms of both drugs, and local economic factors.
Conclusion
This groundbreaking research marks a crucial step forward in the fight against non-dystrophic myotonia, offering new hope for patients worldwide. As lamotrigine demonstrates its potential to deliver effective relief with fewer side effects, it stands to transform the landscape of treatment for this rare muscle disorder.
The study was funded by the Neuromuscular Study Group, Jon Moulton Charity Trust, and the National Institute for Health and Care Research biomedical research center at UCLH. The researchers extend their gratitude to the patients and their families for their invaluable support throughout the trial.
Reference: Vivekanandam, V., Skorupinska, I., Jayaseelan, D. L., Matthews, E., Barohn, R. J., McDermott, M. P., & Hanna, M. G. (October 2024). Mexiletine versus lamotrigine in non-dystrophic myotonias: a randomised, double-blind, head-to-head, crossover, non-inferiority, phase 3 trial. The Lancet Neurology. DOI: 10.1016/S1474-4422(24)00320-X.
