Interferon Beta Responders and Non-Responders

In my opinion, the results from this study don't mean very much. As Art mentions, there is definitely the risk of regression to the mean affecting the results. We all know that an individual's relapse rate can vary over time -- so how many people were classified as responders just because their relapse rate swung downward coincidentally with the start of IFN-b? Conversely, how many nonresponders happened to be at a low rate and then coincidentally swung upward after treatment start? The study also found that responders tended to be older and have longer disease duration, but relapse rate has been shown to decline with duration of disease, so perhaps many of these older, longer-term patients would have had fewer relapses anyway. The finding that longer disease durations are associated with response to IFN-b also seems to contradict the current push toward getting people on IFN-b early after diagnosis (or even after the first symptom), under the hypothesis that IFN-b is most effective early on when inflammation is most operative. Unfortunately, this interesting contradiction was not explored in the study discussion.

My other problem with this study is that it doesn't provide much to go on in terms of predicting who will respond to IFN-b. I think a better course of action is to study biological markers, gene variants, or other physiological evidence for correlations to treatment response or nonresponse. These types of studies are starting to be performed now with IFN-b (see this and this) and provide a much better chance of finding one or more factors (maybe a combination) that more clearly predict whether someone will respond to the treatment or not. Finding such factors would also provide more to go on in terms of understanding the drug's mechanism of action.