Systemic alpha-interferon in multiple sclerosis. Long-term patient follow-up

H. S. Panitch

Twelve patients with relapsing multiple sclerosis who had participated in a clinical trial of systemic (subcutaneous) natural alpha-interferon were interviewed and reexamined 4.3 years after beginning interferon treatment and 2.3 years after completion of the study. There was a progressive reduction in exacerbation rate from 1.33 per year to 0.47 per year. Overall neurologic function and disability did not change significantly. Six patients stabilized or improved, and were able to carry on normal daily activities. There were no long-term deleterious side effects. These results are similar to those described for patients treated with intrathecal beta-interferon. The mechanism of the prolonged beneficial effect is unknown, but is unlikely to represent antiviral activity in the central nervous system, and more probably involves systemic immunoregulatory functions. The systemic route of administration of interferon may be as effective as the intrathecal route in multiple sclerosis, and is potentially less hazardous.