IM interferon β-1a delays definite multiple sclerosis 5 years after a first demyelinating event

The recently published CHAMPIONS trial1 reported that the early use of weekly IFN beta-1a (compared to delayed treatment) reduced the likelihood of developing clinically definite (CD) multiple sclerosis (MS) after a 5-year follow-up period in patients who had initially presented with clinically isolated syndromes (CIS) suggestive of MS. There are concerns both about the trial design and this conclusion. For example, this trial was planned only after the completion of the CHAMPS trial2 and with full knowledge of the CHAMPS results. Additionally, the primary endpoint of the CHAMPIONS trial was the development of CDMS at any time after CIS onset. Consequently, at the outset of CHAMPIONS, there was already a highly significant difference (bias) between groups with respect to the primary outcome measure. Significantly more patients in the delayed treatment group had already reached (and were known to have reached) their final endpoint before the trial even began compared to the early treatment group. Conversely, there were significantly more “survivors” (i.e., those without a second clinical …