Disease evolution in multiple sclerosis.
Disease evolution in multiple sclerosis.
Ebers GC.
University Dept. of Clinical Neurology, Radcliffe Infirmary,
Woodstock Road, Oxford OX2 6HE, United Kingdom,
george.ebers@clneuro.ox.ac.uk.
Multiple sclerosis is a long-term disease that evolves over a
period of 30 to 40 years with progressive accumulation of unremitting
disability. When developing treatments for multiple sclerosis, it is
important to be able to measure accurately the impact of treatments
on disability progression. An analysis of 31 previous clinical trials
revealed that small changes in EDSS scores measured across two or
three years may be insufficiently sensitive to detect sustained
changes in disability reliably. Information from large longitudinal
natural history databases indicates that long-term outcome is largely
independent of previous relapse history, although the occurrence of
relapses complicates the short-term quantification of unremitting
disability. Treatment effects on relapses may thus not predict long-
term effects on disability, although currently available data are
insufficient to settle this issue. Natural history studies show that
the principal determinant of long-term outcome is conversion to a
progressive disease course, which may be related to neurodegeneration
of specific neuronal pathways, for example the corticospinal tract.
For this reason, it is important to develop tools to identify disease
conversion that could be used in future clinical trials.
