During a CIS, there is a subacute attack suggestive of demyelination but the patient does not fulfill the criteria for diagnosis of multiple sclerosis. Treatment with interferons after an initial attack decreases the risk of developing clinical definite MS.

Relapsing-remitting MS
Medications are modestly effective at decreasing the number of attacks in relapsing-remitting multiple sclerosis and in reducing the accumulation of brain lesions, which is measured using gadolinium-enhanced magnetic resonance imaging (MRI). Interferons reduce relapses by approximately 30% and their safe profile make them the first-line treatments. Nevertheless, not all the patients are responsive to these therapies. It is known that 30% of MS patients are non-responsive to Beta interferon. They can be classified in genetic, pharmacological and pathogenetic non-responders. One of the factors related to non-respondance is the presence of high levels of interferon beta neutralizing  antibodies. Interferon therapy, and specially interferon beta-1b, induces the production of  neutralizing  antibodies, usually in the second 6 months of treatment, in 5 to 30% of treated patients. Moreover, a subset of RRMS patients with specially active MS, sometimes called "rapidly worsening MS" are normally non-responders to interferon beta-1b.While more studies of the long-term effects of the drugs are needed,  some data on the effects of interferons indicate that early-initiated long-term therapy is safe and it is related to better outcomes. More recent data suggest that interferon betas does not hasten disability.Interferon-β exacerbates Th17-mediated inflammatory disease. Commercial formulations
Betaferon/Betaseron is marketed today by Bayer Pharma.
The originator was Schering AG (Berlex in North America), now part of Bayer Pharma. Novartis has also introduced Extavia, a new brand of interferon beta-1b, in 2009. References
External links
"Interferon beta-1b". Drug Information Portal. U.S. National Library of Medicine.