||Researchers at the University
of Pennsylvania School of Medicine have found that
natalizumab (TYSABRI®) – a drug that slows disability
and reduces relapse rates in patients with multiple sclerosis
(MS) – also reduces vision loss in patients with relapsing
||Researchers found vision loss – a worsening
of vision defined as a two-line (10-letter) reduction in letter
chart scores – was reduced by as much as 47% among people
taking natalizumab, compared to those taking placebo.
||The study appears in the
April 17 issue of Neurology.
(PHILADELPHIA) – According to a study that appears in the
April 17 issue of Neurology, researchers at the University
of Pennsylvania School of Medicine have found that natalizumab (TYSABRI®) – a drug that slows disability and reduces
relapse rates in patients with multiple
sclerosis (MS) – also
reduces vision loss in patients with relapsing MS. Vision
loss is one of the most common and disabling symptoms of MS.
“Not only does natalizumab prevent the worsening of vision
loss in people with relapsing MS, but it is also associated with
significant reductions in the likelihood of sustained vision loss
due to inflammatory demyelination of nerve fibers that connect
to the eye, a common cause of visual loss in MS,” says Laura
J. Balcer, MD, MSCE, Associate Professor of Neurology and Ophthalmology at Penn, and lead author of the paper.
Using low-contrast letter acuity charts,
researchers found vision loss - a worsening of vision defined
as a two-line (10-letter) reduction in letter chart scores - was
reduced by as much as 47% among people with MS taking natalizumab,
compared to those taking placebo.
Image Courtesy: Precision Vision, LaSalle IL
The researchers analyzed data from two randomized,
double-blind, placebo-controlled, parallel group, phase 3 clinical
2,138 men and women with relapsing MS from clinical centers in
Europe, North America, Australia, and New Zealand. More than
half of the participants received natalizumab every four weeks
for two years, while the remaining participants received placebo. Visits
were conducted every 12 weeks and visual function testing was performed
at each study visit. Low-contrast letter acuity was measured
using low-contrast letter charts (eye charts with gray letters
on a white background).
Researchers found vision loss – a worsening of vision defined
as a two-line (10-letter) reduction in letter chart scores – was
reduced by as much as 47% among people taking natalizumab, compared
to those taking placebo.
"Not only do the findings of the study add to our understanding
of the effects of natalizumab, but the results provide strong
validation for a simple, sensitive, cost-effective, and clinically
meaningful measure of visual function in MS," advises Dr.
Nicholas LaRocca, Associate Vice President, Health
Care Delivery and
Policy Research at the National
The researchers caution that, as with any therapy, the benefits
of natalizumab must be considered in the context of potential risks
or complications. In the case of natalizumab, three confirmed
cases of progressive
multifocal leukoencephalopathy (PML) – a
rare, often lethal brain disease – have been reported.
Despite the fact that vision loss is a common and important cause
of disability in MS, the natalizumab clinical trials were the first
to include a test of visual function. These trials showed
that low-contrast letter acuity eye chart testing is an effective
measure for assessing visual outcomes, and may be useful in future
This study was supported by Biogen
Idec and Elan, makers of natalizumab. Dr.
Balcer has received support for consulting from Biogen Idec as
well as from other companies for work on developing visual outcome
measures for MS clinical trials.
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