Interferons for Relapsing Remitting MS
Taking interferons by injection for two years reduces the chance of having one or more relapses
- Without interferons 69 per 100 people would experience one or more relapses over two years and 31 would not
- With interferons 55 per 100 people would experience one or more relapses over two years and 45 would not
- Therefore with interferons, 14 fewer per 100 people would experience one or more relapses over two years
These figures may seem unfamiliar to you. Commonly, we see the effectiveness of interferons reported as “interferons reduce the risk of relapse by 30%”.
Without interferons, 69 per 100 people with MS are estimated to experience one or more relapses
With interferons, 55 per 100 people with MS are estimated to experience one or more relapses
In technical terms, the result was statistically significant, the confidence intervals did not cross 1 and the boundaries were not wide. This means the effect of interferons was unlikely to be due to chance alone.
Taking interferons by injection for two years may reduce the chance of disability getting worse
- Without Interferons 29 per 100 people would experience worsening disability over two years and 71 would not
- With interferons 20 per 100 people would experience worsening disability over two years and 80 would not
- Therefore with interferons, 9 fewer per 100 people would experience worsening disability over two years
Without interferons, 29 per 100 people with MS are estimated to have worsening disability
With interferons, 20 per 100 people with MS are estimated to have worsening disability
In technical terms, the result was statistically significant, the confidence intervals did not cross 1 and the boundaries were not wide. This means the effect of interferons was unlikely to be due to chance alone. However, many people dropped out of the trials early, which adds some uncertainty to the result.
Interferons are generally well tolerated. Most interferon side effects are mild and can often be relieved with symptomatic treatments, without the need to stop taking them.
- Very common (10-100 per 100)
- Common (1-9 per 100)
- Uncommon (less than 1 per 100)
- There is no information about the side effect
(fever, chills, cough, sore throat, flu-like symptoms)
|Pain and redness at the injection site||●●||●●●||●●●|
|Nausea, vomiting and diarrhoea||●●||●||●●|
|Depressed mood, insomnia||●●||●||●●|
|Skin break down at the injection site||?||●●||●|
|High blood pressure||?||●||?|
|Low white blood cell counts||●●||●||●●●|
|Low red blood cell counts||●●||●||●●●|
|Low blood platelet counts||●||●||●●●|
|Abnormal liver enzyme levels||?||●||●●●|
|Abnormal thyroid hormones||?||?||●|
Sources: This side effect data has been collated by the IN-DEEP project team using publically available data from the European Medicines Agency, Micromedex and the studies included in Cochrane reviews on Interferons.
What we don’t know from the results of this review
The studies included in the Cochrane review, do not give us any information about the effect of interferons on disability getting worse when taken for more two years. This review did not draw any conclusions about whether there was any difference between the effect of the three different interferons (Avonex®, Betaferon® and Rebif®).
To understand the effects and side effects of medications over many years, health professionals and researchers rely on long-term follow up studies, often called observational studies or Phase IV clinical trials. Speak to your health professional or MS Australia staff for more information about the long-term effects of Interferons in people with MS. The web sites listed in Find Out More may also have some links, or you could try the MS Research Australia web site
What about the quality of the included studies?
Overall, the quality of these results is moderate. The studies were randomised controlled trials, which are considered the most rigorous study design that minimises the risk of misleading results. However, many of the studies had major weaknesses; most commonly a large number of participants dropped out before the study ended. This means we are somewhat uncertain about the results.
The really detailed answer
For more information, or to read about the individual studies included in this review, you can access the Cochrane review on which this treatment summary is based:
- Rice GPA, Incorvaia B, Munari LM, Ebers G, Polman C, D’Amico R, Parmelli E, Filippini G. Interferon in relapsing-remitting multiple sclerosis. Cochrane Database of Systematic Reviews 2001, Issue 4