A recently completed study at University College London Hospital suggests that administration of certain drugs can block the entry of sodium ions in nerve cells that in turn can prevent aggressive nerve cell damage. The research team proposed that delaying nerve cell destruction can limit the rate of disability in secondary progressive MS patients. The supporting study, which was completed after two years of testing, was aimed at employing nerve cell blockers like lamotrigine to monitor the rate of worsening disability in secondary progressive MS patients.
The Primary Outcome of this double-blind interventional study was to monitor changes in the volume of the whole brain with the help of the Loseff method using MRI technology (to monitor cerebral atrophy due to loss of axons). Secondary Outcomes for the study included monitoring the changes in the volume of whole brain with the help of Brain Boundary Shift Integral; the rate of atrophic changes in the spinal cord; appearance of new high intensity lesions on an MRI scan; ratio calculation of new T1 and T2 lesions; and the overall rate of changes in the MS Functional Composite and Impact Scale.
Find out more about secondary progressive MS.
The cerebral and spinal volumes and cross-sectional area of the cervical spinal cord were tested at baseline, at 12 months into the study, and towards the end of the study period (24th month). Brain volume was measured more periodically at the 6th and 18 month marks, as well as at the 12 and 24 month marks. The clinical visits were planned for every 3 months.
The research team enrolled 120 patients with a positive history of MS and a progressive course of illness as seen in secondary progressive MS patients (patients with frequent episodes of clinical relapses resulting in disability were excluded). The study sample was divided into a test group and control groups, and the patients were randomly selected to receive either placebo or lamotrigine.
The research team explained that degenerative spinal or cerebral diseases can respond fairly well to neuroprotective treatments. The cause of disease progression in multiple sclerosis is degeneration of nerve axons. Previous research projects conducted by investigators at the University College London Hospitals have concluded that inflammatory mediators like nitric oxide can contribute to axonal degeneration. Various in-vitro studies confirm that blocking the activity of sodium channels can reduce the degeneration of axonal processes. Several pharmacological agents are currently available that are used to block sodium channels in the brain tissue (like phenytoin and flecainide in addition to lamotrigine).
Positive results from the Phase 2 clinical trial will pave the way for Phase 3 clinical trials and also confirm the neuroprotective role of sodium channel blockers in the nerve cell disorders, like secondary progressive MS, to limit the rate of complications and long-term disability.
Lamotrigine is a sodium channel blocker that is widely prescribed for the management of epilepsy and seizure disorders under the brand name of Lamictal XR. Other indications for lamotrigine use are bipolar disorders, mood disorders, attention deficit hyperactivity disorder, and sleep disorders. Like all anti-conculsants, it is also associated with dose-dependent side-effects and is therefore sold as a prescription drug in most parts of the world.