Sclerosis (MS) often starts as an individual episode of neurological
dysfunction. At this early stage, termed a clinically isolated syndrome (CIS),
it is often difficult to predict who will go on to develop definite MS, and who
will have no further episodes. Previous trials have shown that early treatment
with disease-modifying therapies like interferon β-1b can delay the conversion
from CIS to clinically-definite MS. However, it is not known whether early
treatment reduces disability and disease progression in the long-term.
Aim: To assess the effect
of early vs. delayed treatment on long-term outcomes at 11 years after onset of
Method: The initial
BENEFIT trial was a randomised, double-blind, placebo-controlled trial in which
participants received either early (n=292) or delayed (n=176) treatment with
interferon β-1b after onset of CIS. The early treatment group began treatment
within 60 days of onset. The delayed treatment group received placebo until
either 2 years after onset of CIS or onset of clinically-definite MS.
initial 2 year trial, patients were invited to participate in a 3-year
open-label extension. In the 3 year extension period, patients could choose to
have any disease-modifying drug/s, or to have no drugs at all. Patients and investigators were not blinded to treatments in this stage.
The 11 year
follow-up study reassessed patients who were part of the original trial 11
years after onset of CIS. 278 of the original 468 patients were assessed. This
was a cross-sectional, observational study that compared several outcome
measures in the early vs delayed treatment groups. The outcomes measured were: risk
of conversion to clinically-definite MS, time to conversion, relapse rate,
conversion to secondary progressive MS, disability scores, neuropsychometric
scores, MRI appearance, and health resource utilisation.
Results: Patients in the
early treatment group had a lower risk of conversion to clinically definite MS (66.6%
vs 75.0%), a longer lag time until the conversion to clinically definite MS, a
lower average annualised relapse rate over the whole study period (0.21 vs 0.26),
and appeared to have a lower risk of conversion to secondary progressive MS (4.5% vs 8.3%). Average
EDSS scores were similar in the early and delayed treatment groups.
treatment group performed better on the Paced Auditory Serial Addition Task-3
(PASAT-3), in which patients have to add up a series of numbers presented to
them via audio at 3-second intervals. There was little difference between early
and delayed treatment groups’ MRI appearances or health resource utilisation.
Conclusion: Early treatment (within
6 months) of CIS with interferon β-1b leads to clinical benefit over delayed
treatment, and this benefit is sustained 11 years after the onset of CIS.
Interpretation: This impressive
study provides a fascinating insight into the long-term consequences of
different treatment strategies in early MS/CIS. What these results appear to
show is that an aggressive, ‘see and treat’, approach in CIS is better than a ‘watch
and wait’ strategy. We knew already from previous incarnations of BENEFIT that early
interferon β-1b treatment delays the onset of and reduces the risk of
conversion to clinically-definite MS. This 11 year follow-up allows us to work
out whether these benefits actually translate into better long-term quality of
life for patients.
It is therefore
interesting that EDSS scores – a commonly-used measure of disability in MS –
were almost identical in the early and delayed treatment groups. This implies
that while early treatment may stave off the onset of definite MS, it does not improve
long-term disability. There are several possible explanations for this finding.
Firstly, the EDSS scores are very low and stable in the study population, and
so the study might not be sufficiently powered to detect small differences
between the groups. Even still, a small difference in EDSS scores, which might
be missed if the study were underpowered, would not necessarily be clinically significant.
A biological explanation for the lack of obvious benefit in terms of EDSS score
is that the processes involved in disability progression in MS, such as
neuronal and synaptic loss, might be quite separate to the processes
responsible for relapses.
observation is that whilst the overall annualised relapse rate (ARR) was lower
in the early treatment group, the ARR was actually slightly lower in the
delayed treatment group in the final year of follow-up. This might imply that
early treatment produces a long-term but not indefinite reduction in relapse
rate, which levels off by year 11. Intuitively, this makes sense, as the
participants spent 9 years on whatever treatment they and their doctors opted
for, and only 2 years in the stringent, double-blind study period.
participants had received 9 years of treatment since the original study period,
it is remarkable that there were sustained benefits of early treatment in terms
of overall ARR, risk of conversion to clinically-definite MS, time to
conversion, and risk of secondary progressive MS. This could be interpreted as
evidence that there is a crucial window of opportunity when patients have their
first episode suggestive of MS, and that initiating treatment at this stage
produces long-lasting benefits.
there seems to be little harm in starting CIS treatment as early as possible.
However, BENEFIT-11 provides no evidence that this approach leads to long-term
differences in disability, the outcome which probably matters most for quality
of life. It does provide some evidence that early treatment influences the
course of the disease, but this is very difficult to disentangle from effects
of other treatment which patients may have tried in the intervening follow-up
Labels: #ResearchSpeak, Benefit, Beta Interferon, CIS, EDSS