Drug May Treat Multiple Sclerosis, Crohn's Disease

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Drug May Treat Multiple Sclerosis, Crohn's Disease

Wed Jan 1, 5:25 PM ET

NEW YORK (Reuters Health) - An experimental drug has shown early promise in treating both multiple sclerosis (MS) and Crohn's disease, according to two international studies released Wednesday.

Although the two diseases are quite different in their effects, both are thought to arise from an abnormal immune system attack on the body's own tissue. The new drug, called natalizumab, is designed to interfere with this attack.

Initial work with the drug had suggested it could treat both the nervous system disorder MS and the digestive ailment Crohn's disease, and the new studies indicate it might cut the number of symptom attacks patients have.

In the MS study, patients on monthly natalizumab injections had about half as many relapses over a 6-month period as those not given the drug. The Crohn's disease study found that two natalizumab infusions increased symptom-free periods among 248 patients with moderate-to-severe Crohn's.

Both reports appear in the January 2nd issue of The New England Journal of Medicine (news - web sites). Natalizumab is being marketed as Antegren by the US drug companies Elan and Biogen, which funded both studies.

MS is a chronic disorder of the central nervous system in which damage to the myelin sheath that protects nerve fibers leads to symptoms such as muscle weakness, numbness, coordination problems and impaired vision. The disease is believed to occur when the immune system, for unknown reasons, attacks myelin in the brain and spinal cord. Most people with MS have the relapsing-remitting form, which means that symptoms come in waves, interspersed with periods of complete or partial remission.

Similarly, people with Crohn's disease can have periods of remission. The disorder is marked by inflammation in the small intestine, causing symptoms such as abdominal pain and diarrhea. As in MS, a misguided immune assault is blamed for the chronic tissue inflammation.

Natalizumab is engineered to interfere with the process that recruits certain immune system cells from the blood and into the central nervous system or intestine.

Among the 213 MS patients in the current study, 13 of the 68 given a lower dose of natalizumab had a relapse over six months, as did 14 of the 74 given a higher dose. In contrast, 27 of the 71 patients in the placebo (comparison) group experienced a relapse, according to the study authors, led by Dr. H. of the Institute of Neurology in London.

In addition, the treated patients had about 90% fewer new brain lesions. All study patients had relapsing-remitting MS or secondary progressive MS, a form that begins with a period of relapses and remissions then enters a stage of progressive deterioration.

In the Crohn's study, patients who got two infusions of the drug had higher remission rates than placebo patients did at four and eight weeks after treatment, although the remission rate at week six--the study's main point of evaluation--was similar among all patients.

Treated patients also reported improvements in quality of life, according to the report.

However, since the study was only short-term, the longer-term benefits of the drug--and how it compares with other Crohn's treatments--"remain to be defined," the study authors conclude.

The authors of an accompanying editorial agree that natalizumab's value and safety in treating either Crohn's disease or MS is still unclear.

"Firm conclusions...must await the results of much larger, phase 3 studies," write Drs. Ulrich H. von Andrian, of Harvard Medical School (news - web sites) in Boston, Massachusetts, and Britta Engelhardt, of the Max Planck Institute of Vascular Biology in Munster, Germany.

SOURCE: The New England Journal of Medicine 2002;348:15-23,24-32,68-72.