Italian study finds limited benefits of widely used therapy
Feb. 13, 2003
By Ed Edelson
While interferons are widely used to treat multiple sclerosis, the evidence to support their long-term value is too weak to be trustworthy, Italian researchers contend.
A search of the medical literature indicates that while interferons may help patients in the first year after the disease is diagnosed, "their clinical effect beyond one year is uncertain and new trials are needed to assess their long-term effectiveness and side effects," says a report in the Feb. 15 issue of The Lancet.
"We found a modest benefit in the first year of treatment," says Dr. Graziella Filippini, director of the epidemiology unit of the National Neurological Institute in Milan. "There is not sufficient data to estimate the effect after the first year of treatment."
Arney Rosenblat, a spokeswoman for the National Multiple Sclerosis Society, says the report comes as a surprise and the society's medical advisors must study it in detail before making a response.
Meanwhile, she says, "what is important is that people read the American Academy of Neurology guidelines on treatment with interferon." The guidelines list interferon as an accepted treatment.
Multiple sclerosis (MS) is a disease in which the body's immune system, for unknown reasons, attacks and destroys myelin, the tissue that forms a protective sheath around nerve cells. About 85 percent of MS patients have the relapsing form of the condition, with flare-ups that cause symptoms ranging from numbness and tingling to paralysis.
The U.S. Food and Drug Administration has approved three different forms of interferon, biologically engineered versions of a natural immune system molecule, to treat those flare-ups. However, "widespread discussion continues about their true effectiveness, benefits, side effects and costs," the journal report says.
Filippini and her colleagues reviewed all the scientifically controlled studies of interferon treatment on patients with the relapsing form of multiple sclerosis done between 1993 and 2002. They picked out seven trials including 1,215 patients, 667 of whom were followed for one year and 917 of whom were followed for two years.
"Interferon seemed to reduce the number of patients who had exacerbations [flare-ups] during the first year of treatment, but results at two years follow-up were not robust and were difficult to interpret because of the many dropouts," the researchers report.
Those results "do not give a reason to continue treatment after the first year," Filippini says.
Interferon treatment also causes significant side effects, such as fever, muscle pains and headache, the review finds. In one trial that studied the quality of life, patients who received interferon reported consistently lower scores than those who got a placebo, an inactive substance. Overall, medical problems, many affecting the blood, were more common in patients receiving interferon, and "acute toxic effects adversely affected quality of life," the report says.
The case for or against interferon remains to be proved, Filippini says. "There should be a European or world collaboration to consider this problem, and to propose a new study design to define this problem better," she says. "We need a collaboration between the best neurological centers in the world to consider this problem."
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