The FDA said on Jan. 22 it has approved a new drug called Ampyra (dalfampridine) for treatment of multiple sclerosis (MS) to improve walking in patients with the disease.

Ampyra, made by Acorda Therapeutics, is not intended to cure MS.

According to a statement by the drug maker, two trials showed the drug increased the walking speed in a great number of patients by 10 to 30 percent.

While the therapeutic effect may not look as great as many thought, Ampyra can cause adverse effects in more than 2 percent of patients, a rate that was significantly higher than the rate for those on a placebo.

Adverse effects include “urinary tract infection, insomnia, dizziness, headache, nausea, asthenia, back pain, balance disorder, multiple sclerosis relapse, paresthesia, nasopharyngitis, constipation, dyspepsia, and pharyngolaryngeal pain,” the company said in its statement.

Additionally, when the drug is used in overdose, seizures may occur.

Multiple sclerosis, which is believed to affect 400,000 people in the United States alone, is an inflammatory, demyelinating, neurodegenerative disorder that attacks the central nervous system in the brain and spine.  The disease usually is diagnosed in men and women aged 20 to 50 and results in physical disability.

There is no cure for multiple sclerosis.  But previous studies suggest that something can be done to reduce the risk for the disorder even though its etiology remains largely unknown.

One recent study published in the Nov. 2009 issue of Neurology suggests that obesity during childhood and adolescence may increase the prevalence of MS.

The study led by K. L. Munger and colleagues at Harvard School of Public Health in Boston, Massachusetts examined the association between obesity during childhood, adolescence and adulthood, and the risk of multiple sclerosis.

Study subjects included 121,700 women in the Nurses’ Health Study and 116,671 women in Nurses’ Health Study II. The researchers analyzed data on subject’s body weight at age 18 and body mass index (BMI) at baseline and confirmed 593 MS cases.

Obesity at age 18, defined as having BMI greater than 30 kg/m2, was found associated with more than twofold increased risk of MS.  While having a large body size at ages 5 or 10 was not associated with the risk, a large body size at age 20 was correlated with a 96 percent increased risk for the disease.

Munger and colleagues concluded that “obese adolescents have an increased risk of developing multiple sclerosis” and “this result suggests that prevention of adolescent obesity may contribute to reduced MS risk.”

Many studies have also suggested vitamin D deficiency may be a risk factor for MS. People who have high levels of serum vitamin D are found less likely to acquire MS.

Source:

Neurology. 2009 Nov 10;73 (19):1543-50.

Body size and risk of MS in two cohorts of US women.

Munger KL, Chitnis T, Ascherio A.

Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA.

Reporting by David Liu and editing by Sheilah Downey
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