Patients with Huntington's disease might have hope for relief from chorea, a key cause of disability and death in individuals afflicted with the hereditary disease. On Friday, the FDA approved Prestwick Pharmaceutical's Xenazine (tetrabenazine) for use in the U.S. The drug had previously received approval for use in Europe, Australia and Canada.
Huntington's disease is a rare, inherited and ultimately fatal disease that causes uncontrolled movements, decreased mental status and early death. Currently, about 30,000 people in the US have a diagnosis of Huntington's disease. Affected individuals first develop symptoms between 30 and 50 years of age and have a life expectancy of about 15 to 20 years after symptom onset.
The new drug will help reduce the jerky, rapid, involuntary movements that characterize chorea, which often make it difficult for sufferers to walk, talk or perform basic functions and result in many of these patients becoming shut-ins. The medication works by suppressing dopamine at key communication channels in the brain, which helps reduce symptoms since dopamine is overactive in people with Huntington's disease.
Xenazine will be the only FDA-approved treatment specific for Huntington's disease, according to the Hereditary Disease Foundation. However, the drug--which is not a cure for the condition--also has side effects, including an increased risk of depression and suicidal behavior as well as lesser adverse effects such nausea, drowsiness, restlessness and insomnia. Due to the nature of the disease, depression is often a factor already, and the FDA is requiring a special monitoring program for worsening psychiatric symptoms.
The FDA also granted Xenazine orphan drug status, which guarantees additional patent protection and will help Prestwick alleviate some of the development costs.