Therapy targets cause of chronic fatigue
Sufferers of chronic fatigue syndrome are plagued with flu-like symptoms, joint and muscle aches, a loss of mental acuity and such profound lethargy that even routine activities can be exhausting.
But the debilitating disorder has no known cause or specific treatment.
An experimental therapy may change this bleak prognosis by lifting the mental fog and increasing physical stamina. For some patients, this could mean a return to normal existence.
“I’m hopeful this drug will meaningfully improve people’s quality of life,” says Dr. Nancy G. Klimas, an immunologist and chronic fatigue expert at the University of Miami School of Medicine in Florida. “These patients are often desperately ill.”
Chronic fatigue afflicts an estimated 500,000 to 1 million Americans, more than half of whom are women. Symptoms can include headaches, forgetfulness, impaired concentration, dizziness, sore throat, fever, muscle weakness, night sweats and an inability to achieve restful sleep.
Although experts are unsure what triggers the symptoms, they suspect that a chronically hyperactive immune system is to blame. The immune system appears to saturate the body with killer cells and proteins that normally are dispatched only when repelling a bacterial or viral invasion.
Doctors use a variety of therapies, such as antidepressants and pain relievers, to relieve symptoms, but the experimental treatment Ampligen could become the first that targets the illness’ underlying cause.
The injectable drug is composed of synthetic genetic material that is similar to a virus.
“The body interprets this drug as a virus and reacts accordingly,” says Dr. William A. Carter, a co-inventor of Ampligen and chief executive of Hemispherx Biopharma Inc. in Philadelphia, which makes the drug.
Exposure to the synthetic virus prompts the body’s immune system to produce interferons, which are proteins that combat viruses and dampen an overactive immune response.
Recent test results were encouraging. In a 40-week study, 234 people with severe chronic fatigue were given either twice-weekly injections of Ampligen or a dummy shot. The treated patients experienced a 21% improvement on a treadmill test (a measure of exercise capacity), compared with about 5% in the placebo group.
In addition, the Ampligen group reported feeling sharper mentally; about 80% stopped or reduced their use of other medications, and a handful were able to go back to work.
Although the overall findings show a modest benefit, “these are people who normally can’t do anything strenuous without getting sick, and the majority of patients experienced an improvement in their most difficult-to-reverse symptoms,” says Dr. Lucinda Bateman, a chronic fatigue specialist in Salt Lake City who helped test Ampligen.
The company hopes to have Ampligen on the market in 2006.
“I’m excited but cautious,” says Klimas. “This drug is quite beneficial for some patients, and the next step is to figure out how to predict which ones this can truly help.”
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Also in the works
Experimental tests of two drugs approved to treat other conditions also show promise in treating chronic fatigue syndrome.
The wakefulness agent Provigil, a treatment for narcolepsy and excessive daytime sleepiness, decreased lethargy in a small study of chronic fatigue patients. Procrit, which is used to boost the volume of oxygen-carrying red blood cells in patients undergoing chemotherapy, is also being studied for its potential ability to combat fatigue in chronic fatigue patients.
