The earlier use of natalizumab!

Biogen-Idec and Elan have announced the eminent start of a clinical trial, called Surpass, to assess the effectiveness of switching to natalizumab (Tysabri) in patients that have experienced disease breakthrough with either glatiramer acetate or interferon beta.

I interpret this as a show of confidence by the companies that we can overcome the PML problem; there are now 31 confirmed cases of post-marketing PML in patients with MS receiving natalizumab.