Among the classic signs of Huntington's disease is the development of chorea, involuntary, rapid, irregular, jerky movements that may include the face, arms, legs or trunk. The disease is hereditary and includes progressive neurodegenerative symptoms including emotional, behavioral and psychiatric abnormalities. The condition was originally described in 1872 by Dr. George Huntington, who studied a Long Island family with a high percentage of affected members. Symptoms of the disease are usually not apparent until the individual is in their late forties to early fifties.
Since the disease was first discovered 136 years ago there has been little effective treatment and no hope for those affected with the disease. The neuron loss, which is the root of the disease, is not fatal but the complications reduce life expectancy. Since it is a dominant trait in the genetic inheritance sequence it can be inherited when only one parent carries the gene.
In 1993, the gene which causes HD was found and, with the cause of the disorder known, an accurate test became possible. The disease is not widespread, with only about 30,000 patients in this country currently living with HD. With a relatively low patient base, drug companies would have problems providing an affordable drug for the population and meeting their own need for profitability in research and production.
Under an FDA policy known as the "orphan products program," aimed at developing treatments for conditions which affect fewer than 200,000 people, a medication named Xenazine has been approved. The orphan products program gives financial assistance to the company who is developing the product and also gives the company exclusive sales rights to the product for a specific number of years.
Xenazine is the trade name of tetrabenazine and has been previously approved for treatment in Australia, New Zealand, Canada, Denmark and UK. It has been used in the treatment of Tourrette's syndrome which is also characterized by uncontrollable movements.
Dr. Frederick J. Marshall, a University of Rochester Medical Center neurologist who led the clinical study presented to the FDA said, "A lot of patients won't go out because they are embarrassed by those movements; suppressing the movement means a lot to people with Huntington's disease." Xenazine will not cure the condition, but it provides relief for the major disabling symptom of chorea. This is the first time that any kind of treatment has been available in the United States.
Xenazine does have the possibility of serious side effects and the patients treated with the drug will be monitored by a special risk management program for increase of psychiatric symptoms.
According to Marshall many patients with Huntington's have gone untreated, others have experimented with anti-psychotic drugs or imported Xenazine from abroad in violation of U.S. law. Approval of the drug means that patient's medication should now be approved by Medicare and other insurance programs.
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