Background
Myotonic disorders are a group of genetic diseases characterized by the presence of myotonia, which is defined as failure of muscle relaxation after activation. The presentation of these disorders can range from asymptomatic electrical myotonia, as seen in some forms of myotonia congenita (MC), to severe disability with muscle weakness, cardiac conduction defects, and other systemic features as in myotonic dystrophy type I (DM1). The most prevalent form of muscular dystrophy in adults, DM1 is estimated to affect more than 100,000 people in the U.S., many of whom experience decades of progressive disability, with a median survival of 55 years of age. Due to the debilitating and progressive nature of these disorders, the resulting disability and loss of quality of life in patients, the significant cost of supportive care, and the lack of ultimate cure, there is a need for new and effective means to treat myotonic disorders.
Technology Overview
Previous evidence suggests that agents capable of inhibiting calcium channels, such as calcium channel blockers, are effective for treating or alleviating the symptoms of myotonic disorders. We have developed a method for treating a myotonic disorder that involves administering to a subject in need a calcium channel blocker, such as verapamil alone or in combination with other therapeutic agent such as ranolazine mexiletine, flecainide, tocainide, phenytoin, carbamazepine, or lamotrigine.
Benefits
Verapamil has an excellent safety profile, oral bioavailability, stability in food without special slow release formulation, relatively long half-life, use-dependence and mode of action as a pore blocker, and absence of muscle excitability and excitation-contraction coupling (ECC) inhibition. The combination therapy may provide synergy and be synergistic, i.e. the effect achieved when the active ingredients used together is greater than the sum of the effects that results from using the compounds separately.
Applications
Myotonic disorders.