Incidence of exacerbations in the first 90 days of treatment with recombinant human interferon β-1b in patients with relapsing-remitting multiple sclerosis

Interferon beta-1b (IFN beta-1b) is effective in reducing the frequency of exacerbations in patients with relapsing-remitting multiple sclerosis (RRMS). Recently, a study suggested that treatment with IFN beta-1b may place MS patients at risk of exacerbations by increasing interferon-gamma (IFN gamma)-secreting cells in the blood early after onset of treatment. We conducted a retrospective study in 192 RRMS patients treated with IFN beta-1b. We did not observe an increase in the frequency of exacerbations early after the onset of treatment and suggest that the IFN gamma-secreting cell surge linked to the onset of treatment with IFN beta-1b may not be clinically significant.