News: first case of PML on fingolimod

Novartis announced yesterday that an MSer treated with fingolimod had been diagnosed with PML. Importantly the MSer concerned had previously been treated with natalizumab. 

As you are aware natalizumab is strongly associated with PML. Therefore it is difficult to point a finger at, or blame, fingolimod as the cause of the PML in this specific case. However, fingolimod is likely to have contributed to the problem. This is why it is essential for neurologists to make sure that the risk of PML carry-over, when swicthing from natalizumab to fingolimod, is minimised. This is why we, at the Royal London Hospital,  stop natalizumab for at least 3 months, and do a lumbar puncture, and MRI scan to make sure that there is no sub-clinical evidence of PML, before starting fingolimod. We think there is a asymptomatic period of several months before PML causes symptoms and presents clinically. The problem with fingolimod is that once it is your system it takes a long time for it wash-out after stopping the drug; weeks to months. Therefore if you develop PML on fingolimod it will take months for your immune system to reconstitute to a level were it can fight the JC virus that causes PML and hopefully allow you to recover from the infection. Unfortunately, many of us predicted this complication and have been speaking about it for sometime. This case is unlikely to be the last case of PML in MSers on fingolimod. We need to be vigilant and limit the risk as much as possible.

Source
Marta Falconi. Novartis Gilenya Patient Gets Rare Brain Disease. Wall Street Journal. April 13, 2012, 9:17 a.m. ET.

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