We have been saying one of the important considerations when starting treatment is how do you switch off your drug, we reported rebound after fingolimod and this is a well known problem with Natalizumab. PML is the other major problem with natalizumab.
The first case of PML on ocrelizumab has been reported. Again one suspects that subclinical PML due to natalizumab was the problem. According to Media the case occurred in a JC virus-positive pwMS who had stopped taking natalizumab in February after being on the drug for three years, and switched to ocrelizumab with a first dose given in April. Ocrelizumab is not licenced within Europe but it was apparently used in Germany where the case occurred.
ProfG will no doubt get the details, but perhaps not the news you want when going to the regulators to get approval for use in Europe.