Extended observations on MS patients treated with IM interferon-beta1a (Avonex): implications for modern MS trials...

Extended observations of the pivotal phase III clinical trial of interferon-beta1a (IFNbeta1a; Avonex, Biogen) in relapsing MS patients revealed that: (1) active treatment significantly slowed the accumulation of physical disability over time, reduced clinical exacerbations and MRI brain lesions; (2) clinical efficacy did not depend on disability endpoints; (3) active treatment benefited multiple MRI measures of brain lesions; (4) cerebral atrophy occurred over 2 years in relatively mildly disabled patients; and (5) Avonex could slow the development of atrophy after the first year of treatment. Data from this study were recently used to design a new outcome measure for MS clinical trials (the Multiple Sclerosis Functional Composite), and was also the basis for two ongoing studies of IFNbeta1a: one in patients with monosymptomatic onset of MS and the other in secondary progressive MS.