Natural alpha interferon in multiple sclerosis: results of three preliminary series

In three preliminary, sequential series conducted between 1987-1991, natural human leukocyte interferon-alpha [HuIFN(Le)] was evaluated in 49 interferon-naive multiple sclerosis (MS) patients. In this study, safety data are reported for all 49 patients, and efficacy data for 45 of 49, each patient having received 3-12 months of therapy during the initial study year with observation only in the second year. No major side-effects for HuIFN(Le) were observed at doses of 5-30 million international units (MIU) per week for 3-12 months, although severe fatigue caused some patient drop-outs prior to completion of 3 months of therapy. The relapse rate in patients having received HuIFN(Le), prospectively evaluated in two series (34 patients), was reduced by 80% at 2 years. An unexpected trend towards improved disability provoked a retrospective analysis. In the first year, 36 of 45 (80%) patients improved or stabilized (P = 0.0001); of these 26 of 45 (58%) improved and 10 of 45 (22%) stabilized (P = 0.0023, chi 2 = 9.3). In year 2, 34 of 45 (76%) were improved/stabilized (P = 0.001); of these, 24 of 45 (53%) remained improved and 10 of 45 (22%) remained stable (P = 0.01, chi 2 = 6.6). A trend to greater efficacy at the higher doses for longer periods of therapy, up to 12 months, was observed.