The efficacy of natiluzimab therapy was established in clinical trials.  It soon, emerged, however that this “life changing” medication was potentially associated with a devastating

infectious disorder of the brain, progressive multifocal leucoencephalopathy (PML).  This side-effect resulted in withdrawal of the medication from clinical use for a period of time.  Since re-introduction rigorous screening and monitoring techniques have been developed in order to prevent the development of PML.  In an OnLine first publication Butzkueven and colleagues evaluated the long-term efficacy and safety of natiluzimab in patients with RRMS.  Not surprisingly, the efficacy was very good, with marked reduction of relapse rates, being maintained for 5 years.  Importantly, the risk of PML was low, with only 18 cases reported (total cohort 4821).

Perhaps the screening strategies have indeed been effective.

Read more at:  http://jnnp.bmj.com/content/early/2014/02/14/jnnp-2013-306936.long