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Plasma Exchange Potentially Useful
for Severe MS Relapses
Medical Update Memo
October 20, 1999
Summary
Researchers at the Mayo Clinic in Rochester, Minn., reported
that a small study of plasma exchange therapy indicates the
procedure may be helpful in treating severe attacks of MS that
do not respond to the usual treatment with high-dose corticosteroids.
The researchers emphasized that plasma exchange should not be
considered as a "first-line" treatment for MS attacks,
and that it is not a cure for the disease.
Background
A team of researchers at the Mayo Clinic led by Dr. Brian
Weinshenker announced at an international MS research meeting
in Switzerland in September that a procedure called plasma exchange
therapy may be useful in treating people with MS experiencing
severe attacks which do not respond to conventional corticosteroid
treatment.
The investigators treated 22 people of whom
12 had MS and who were having acute MS attacks with severe neurological
impairment. The others had other types of inflammatory, demyelinating
diseases. All participants had been treated with the standard
regimen of high-dose corticosteroids but did not respond. Treatment
with plasma exchange was carried out within approximately three
months of the attack and soon after the failed steroid therapy.
Four of the 12 people (33%) with MS treated
with plasma exchange were considered treatment successes. They
had functional improvement in at least one neurological area
that had been affected by the MS attack. In the overall group
of 19 courses of active treatment, eight (42%) experienced moderate
to marked improvement in the neurological functioning.
However, the investigators noted that plasma
exchange cannot be considered a cure. Four treated individuals
who were treatment successes (not necessarily those with MS)
as well as five who were considered treatment failures, went
on to experience further attacks during six months of follow-up
observation.
Plasma exchange involves removing blood from
the body, mechanically separating the blood cells from the fluid
plasma, then mixing the blood cells with replacement plasma
and returning the mixture to the body. Plasma contains immune
factors that may be responsible for sustaining disease activity,
so replacing the plasma with another fluid may dilute the activity
of the immune factors.
In the study, participants had seven treatments,
one every other day for 14 days. One group received active plasma
exchange and the other a placebo (sham) exchange of plasma.
After seven treatments, those who improved did not receive further
treatments but those who did not show improvement, then received
active treatment.
A common side effect was anemia, but it caused
no symptoms and cleared up without additional intervention.
Two participants in the sham treatment group died during this
stage of the study, one because of their underlying illness
and the other because of a rare complication of anticoagulation.
Another person who was considered a treatment success died during
the follow-up phase of the study.
Plasma exchange is carried out at major medical
centres in Canada, and is used as a treatment for myasthenia
gravis. It is not known whether the cost of the treatment would
be covered since it would be considered experimental for MS
at this time. Approximate cost is about $18,000 to $20,000 for
a series of treatments.
Plasma exchange may be useful in treating
individuals who are having severe attacks of MS that do not
respond to standard high-dose corticosteroid therapy. Approximately
90% of individuals with severe MS attacks respond favourably
to steroid treatment. There is no evidence that plasma exchange
modifies the course of MS, nor is it a cure.
Disclaimer
The Multiple Sclerosis Society of Canada is an independent,
voluntary health agency and does not approve, endorse or recommend
any specific product or therapy but provides information to
assist individuals in making their own decisions.
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