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"Interferons in relapsing remitting multiple sclerosis: a systematic
review"
Graziella Filippini, Luca Munari,
Barbara Incorvaia, George C Ebers, Chris Polman, Roberto D'Amico,
George P A Rice
Summary
Background Recombinant interferons have been approved by many
national regulatory agencies for treatment of relapsing remitting
multiple sclerosis, but widespread discussion continues about their
true effectiveness, benefits, side-effects, and costs.
Methods
With
the Cochrane Collaboration methodology, we reviewed all published,
randomised, placebo-controlled trials of recombinant interferons
undertaken in patients with relapsing remitting multiple sclerosis
between 1993 and 2002. Our primary aim was to find out whether
recombinant interferons reduced the number of patients who had
clinical exacerbations and disease progression, compared with
placebo.
Findings
The
seven trials that met our criteria included 1215 randomised
patients: data from 667 (55%) were available for analysis at 1
year's and from 919 (76%) at 2 years' follow-up. Interferon seemed
to reduce the number of patients who had exacerbations during the
first year of treatment (relative risk 0·73, 95% CI 0·54-0·99), but
results at 2 years' follow-up were not robust and were difficult to
interpret because of the many dropouts.
Although the number of patients who had
exacerbations (0·81, 0·74-0·89) or progressed (0·70, 0·55-0·88)
during the first 2 years fell significantly in the protocol
analysis, results were inconclusive after sensitivity analyses for
exacerbations (1·11, 0·73-1·68) and disease progression (1·31,
0·60-2·89).
Data were insufficient to establish
whether steroid use and admissions to hospital were reduced in the
interferon group. Similarly, MRI outcome data could not be analysed
quantitatively. Side-effects were common, and acute toxic effects
adversely affected quality of life.
Interpretation
Recombinant interferons slightly reduce
the number of patients who have exacerbations during first year of
treatment. Their clinical effect beyond 1 year is uncertain and new
trials are needed to assess their long-term effectiveness and
side-effects.
Lancet 2003; 361: 545-52 [PubMed
Link]
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