Gilenya and PML - A New Concern

Multiple Sclerosis patients are again seeing headlines about a disease modifying drug causing Progressive Multifocal Leukoencephalopathy, or PML, in a patient – this time that drug is Gilenya (fingolimod), the oral pill from Novartis. The US Government Food and Drug Administration (FDA) issued a warning for this drug on August 29, after a single person in Europe contracted PML after taking Gilenya for 8 months.

PML is an often fatal infection of the brain, and has been seen in other patient populations outside of the MS world. PML was originally found in a person being treated with immunosuppressive cancer drugs.  PML is found only in people who are JC Virus positive – JC being the initials of the first human who was diagnosed with this virus antibody. It seems more than half the population has been exposed to the JC Virus and will test positive for its antibodies, but it takes the right catalyst for the JC Virus to turn into PML.

PML in MS patients has been previously linked to treatment with Tysabri (nataluzimab), made by Biogen Idec.  Tysabri was pulled off the market in 2005, after there were deaths caused by PML directly linked to this drug.  Tysabri is a rare example of a drug that had such horrible side effects, being banned by the FDA, and then resurrected for use in 2006, on the demand of MS patients and treatment providers because it is an effective drug in delaying relapses.  There have been at least 347 confirmed cases of PML in MS patients using Tysabri, and its administration is now done through an intense patient monitoring program.

Gilenya was approved for use by people with Relapsing Remitting MS in the US in 2010, and Novartis’ market data shows that at least 71,000 people have used Gilenya. One case of PML in 70,000 sounds like pretty small odds unless you happen to be that one person, then it is hugely significant.

There had been an earlier reported case1of a patient on Gilenya who contracted PML, but that person’s medical history was unclear, since the patient had previously been on Tysabri.  The question had to be asked as to which drug, or if it was a combination of the two, that increased this person’s risk for PML.

The European patient who contracted PML had not been on Tysabri prior to Gilenya.

Researchers have also seen cases of PML in persons in Europe taking dimethyl fumarate, when it was used as a treatment drug for psoriasis.  A revised form of this drug has recently won approval from the FDA for Biogen Idec to market as Tecfidera (formerly known as BG-12).

Gilenya has a number of pretests and monitoring that must be done for the first dose administration, most particularly dealing with cardiac conditions.  A screening test for the JC Virus was developed for use with patients on Tysabri, and we may see the same test or a similar one added for Gilenya and Tecfidera users if PML appears to be connected to these drugs.

In the meantime, all of us one these drugs, I am on Tysabri, need to continue to weigh the risks versus the benefits of these treatments, have informed conversations with our Neurologists and not be swayed only by the headlines.

Wishing you well,


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