MS Speaks

We hear a lot about the risk of developing PML if we take Tysabri or some of the other MS treatments, and some studies have been done that have shown that patients often have a dim understanding of what is meant by, for example, a 1-in-1000 risk of developing PML--which was the level of risk Biogen stated (some time ago) that would be acceptable for Tysabri.

Some patients are at a much greater risk of PML if they take Tysabri than others, as it turned out.

This chart gives an idea of levels of risk in general.