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.
Labels: fingolimod, PML