We treated seven patients with subacute sclerosing panencephalitis with beta-interferon and oral inosiplex for 2 to 15 months. Stabilization or improvement was observed in three patients. The effect of treatment was equivocal in two other patients who became stable. The disease continued its progression in the remaining two patients who died. Treatment shorter than 2 months was not effective. Changes in electroencephalograms (EEG), magnetic resonance images (MRI), or cerebrospinal fluid measles antibody levels did not have a close correlation with clinical course. These results suggest that beta-interferon might be efficient in some patients with subacute sclerosing panencephalitis and justify its trial in larger studies with longer follow-up.