Interferons have been used in the treatment of multiple sclerosis for over a decade; doubts remain as to their effectiveness, in particular whether they can really prevent progression of the disease and whether the effect is sustained over time. Recombinant interferons have been approved by many national regulatory agencies, and they are widely used in clinical practice.
Graziella Filippini from the National Neurological Institute, Milan, Italy, and Coordinating Editor of the Cochrane Multiple Sclerosis Review Group and colleagues reviewed all published, randomised, placebo-controlled trials of recombinant interferons undertaken in patients with relapsing remitting multiple sclerosis between 1993 and 2002.
Seven trials were assessed, which included 1215 randomised patients: data from 667 (55%) were available for analysis at 1 year and from 919 (76%) at 2 year follow-up. Interferon seemed to reduce the number of patients who had exacerbations during the first year of treatment by around a quarter--however results at 2 years' follow-up were not conclusive. Furthermore, side-effects were common, and acute toxic effects adversely affected patients' quality of life.
Graziella Filippini comments: "We conclude that there is evidence for a modest effect of interferon in the first year of treatment in reduction of the number of patients with relapsing remitting multiple sclerosis having exacerbations. However, although interferon is widely used in clinical practice and patients are treated for long periods, its clinical effect beyond 1 year is not clear, and should be assessed. Future trials should be better designed, all patients followed with minimal or no dropouts, and their reporting improved in order to allow better use of available data. In our review in fact 240 (20%) patients have to be excluded for insufficient information on follow up".
Contact: Dr. Graziella Filippini,
Epidemiology Unit and Clinical Trial Centre,
Cochrane Multiple Sclerosis Review Group,
National Neurological Institute "C Besta",
Via Celoria 11, 20133 Milan, Italy;
T) 39-02-239-4381;
F) 39-02-706-38217;
E) gfilippini@istituto-besta.it
Journal
The Lancet