[Natural interferon-beta in the treatment of relapsing-remitting multiple sclerosis: a multicenter, randomized,...

The ability of natural human interferon beta (n-hIFN beta) to reduce multiple sclerosis (MS) activity was investigated in 60 patients with relapsing-remitting MS (RRMS).

Patients were randomized to receive either 9 MIU (33 micrograms) of n-hIFN beta by subcutaneous route, three times per week, on alternate days, during one year, or no treatment (control group) during the first six months and then switched to the same treatment for the following six months. Disease activity was monitored monthly by both magnetic resonance imaging (MRI) and clinical parameters. An intergroup analysis (first 6 months of the study) showed fewer active lesions and lower exacerbation rate in the treatment group than in the control group. Similarly, there were more exacerbation-free patients in the treatment group during this time.

When switched to treatment, the control group showed a significant reduction in the number of active lesions (p = 0.00001) and the exacerbation rate decreased by half. Exacerbation-free patients more than doubled (p = 0.006) and the median time to first exacerbation was significantly prolonged (96 vs > 180 days; p = 0.019). Treatment was extended for 12 additional months at a dose of 6 MIU (22 micrograms) once a week and disease activity persisted under control in 88% of patients. Treatment with n-hIFN beta was well tolerated, adverse events being mild and self-limiting. Sera were analyzed for anti-IFN beta antibodies and neutralizing activity was found in 12% of the patients after two years.

The results of this phase II study show, that n-hIFN beta promotes a significant reduction of disease activity in RRMS as shown by both MRI and clinical variables, and that the treatment is well tolerated, with low antigenicity.