Multiple Sclerosis Drug Combats Vision Loss

But doctors must weigh the potential risks of Tysabri, experts say.

By Steven Reinberg
HealthDay Reporter
Tuesday, April 17, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

TUESDAY, April 17 (HealthDay News) -- A controversial multiple sclerosis drug called Tysabri also reduces vision loss associated with the disease by 47 percent, a new study found.

"Vision loss is probably one of the most disabling things that happens to people with MS," said lead researcher Dr. Laura J. Balcer, an associate professor of neurology at the University of Pennsylvania School of Medicine. "The exciting thing is, first, that we now have an eye-chart test that can pick that up and can show if treatments help vision. Second, this particular drug appears to help prevent vision loss."

In the study, Balcer's group looked at the results of two trials -- called AFFIRM and SENTINEL -- that included 2,138 people with relapsing MS. More than half the patients received Tysabri (generic name natalizumab) every four weeks for two years.

To evaluate eyesight, the researchers used a specially developed eye chart of low contrast letters. They found vision loss was reduced by as much as 47 percent among the people taking Tysabri, compared with those taking a placebo.

"Vision is one more dimension of MS that the drug helps," Balcer said. "It has already been shown that the drug reduces the rates of relapses and disability."

Balcer thinks that other MS drugs may have similar effects on vision, and there is now a test that can be included in trials to evaluate this. "Now, we can get to see how these other medications may help vision," she said.

The findings are published in the April 17 issue of the journal Neurology.

Tysabri's history has been marked by some controversy.

It received U.S. Food and Drug Administration approval in November 2004, only to be pulled from the market three months later after several patients in clinical trials developed a rare but deadly viral infection of the brain called progressive multifocal leukoencephalopathy. In June 2006, the FDA allowed the drug to return to the mart, but with strict conditions. According to the new guidelines, Tysabri can only be administered by approved doctors, infusion sites and pharmacies that register and comply with a patient-safety program designed by Biogen-IDEC, the maker of Tysabri, and approved by the FDA.