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Over half of all people with first-time optic neuritis, a
vision-impairing inflammation of the optic nerve, will eventually
develop multiple sclerosis (MS).
But researchers reported in the New England Journal of
Medicine that treating first-time optic neuritis patients with a
combination of intravenous and oral corticosteroids lowers their
risk of developing MS within the next two years.
MS is a debilitating disease of the central nervous system
that affects as many as 500,000 Americans. This finding, based
on two-year patient followup from a large National Eye Institute-
supported clinical trial, offers the first scientific evidence
ever that intravenous corticosteroids help to delay the
progression of MS.
It also suggests that this treatment may provide similar benefits
for people with not only optic neuritis, but other early symptoms
of MS.
"Based on this finding, doctors should strongly consider
treating their optic neuritis patients with intravenous
corticosteroids, even though this regimen has only a marginal
impact on a patient's recovery of vision," said Roy Beck, M.D.,
Ph.D., chairman of the Optic Neuritis Treatment Trial (ONTT) and
a professor of ophthalmology and epidemiology at the University
of South Florida.
"Optic neuritis is often an early sign of MS, and subsequent
inflammations of the central nervous system may lead to increased
disability," said Dr. Beck. "If future attacks of MS can be
delayed or prevented with intravenous corticosteroids, patients
may be able to maintain a higher quality of life."
In the ONTT, researchers evaluated 389 patients with optic
neuritis who had no other clinical signs of MS when they entered
the study. Each patient was randomly assigned to one of three
treatment groups: (1) high-dose intravenous methylprednisolone
for three days followed by a lower dosage oral prednisone for 11
days, (2) oral prednisone for 14 days, and (3) oral placebo for
14 days.
The investigators found that within the first two years, MS
developed in 7.5 percent of the intravenous group, 14.7 percent
of the oral corticosteroid group, and 16.7 of the placebo group.
The researchers also determined that the protective effect of
intravenous therapy lessened after two years, suggesting the need
for future studies on possible retreatment strategies.
Dr. Beck stated that he and the other researchers were
uncertain how the intravenous therapy slowed the onset of MS, in
part because the exact cause of the disease is still unknown.
In addition, the ONTT confirmed previous reports from
smaller studies that magnetic resonance imaging (MRI) brain scans
can frequently help doctors detect asymptomatic brain lesions in
optic neuritis patients that are related to early MS.
In the study, nearly 25 percent of patients with abnormal
brain scans developed MS within two years compared to only 5
percent of those with normal brain scans. The more abnormal the
initial brain scan, the more likely a person was to develop MS.
Moreover, participants with abnormal brain scans benefitted
most from the intravenous corticosteroids. Thirty-six percent
of
patients in the placebo group who had two or more brain lesions
developed MS within two years compared to 16 percent of those in
the intravenous group.
Because of this finding, the researchers stated that
intravenous corticosteroid treatment may also benefit those with
other early symptoms of MS.
"The ONTT is a good example of how the results from vision
research can have an impact on a related medical discipline,"
said Carl Kupfer, M.D., director of the National Eye Institute.
"Since the eye provides nearly 40 percent of our sensory input to
the brain, it provides an excellent opportunity to study many of
the disorders that affect the brain."
Optic neuritis affects more than 25,000 Americans each year,
primarily women between the ages of 18 and 45. Because studies
show that at least half of the people who have an initial attack
of optic neuritis will develop MS within 15 years, many
physicians consider the disease to be a precursor or early
manifestation of MS.
Optic neuritis causes pain and a rapid, often extreme, loss
of vision. ONTT scientists reported previously that even without
treatment, patients generally recover their vision after the
first episode of the disease.
Patients treated with intravenous corticosteroids recovered
their vision about two weeks sooner than those receiving a
placebo, but this treatment provided them with no long-term
visual benefit.
The researchers also found that oral corticosteroids alone
are ineffective in treating optic neuritis, and that treatment
with these drugs can actually increase a person's risk for future
attacks of optic neuritis.
The National Eye Institute, a part of National Institutes of
Health, is the Federal government's lead agency for the conduct
and support of research on the human visual system in health and
disease.
Source: National Institutes of Health
Document ID: lhf00486
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