Ocrevus and PML: Should We Be Worried?

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by Ed Tobias |

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The journal JAMA Neurology recently reported that a 78-year-old man with progressive multiple sclerosis died after being diagnosed with progressive multifocal leukoencephalopathy (PML), a brain disease. The man, diagnosed with MS about 30 years ago, had been treated for two years with Ocrevus (ocrelizumab), and had no previous immunotherapy, the journal reported. 

As of last December, 10 cases of PML had been reported in people being treated with Ocrevus since the U.S. Food and Drug Administration (FDA) approved the disease-modifying therapy (DMT) in March 2017, according to Ocrevus developer Genentech. But this man’s case is different from the other nine.

In the other cases, patients were previously treated with either Tysabri (natalizumab) or Gilenya (fingolimod) before being treated with Ocrevus. Genentech said that in nine patients, Ocrevus treatments were not determined to have been solely responsible for the PML infections. In the 10th case, however, Ocrevus was the only DMT the patient had received. 

What happened?

According to JAMA Neurology, the man was diagnosed with PML after experiencing vision problems and confusion for two weeks. His symptoms progressed over the next few weeks and included vision loss, facial droop, and difficulty speaking.

Doctors discontinued his Ocrevus treatment and began therapy with the cancer medication Keytruda (pembrolizumab) and other medications. But the man’s condition declined rapidly, leading to his death. An autopsy confirmed the PML diagnosis. 

Immunosenescence likely a factor

Doctors also noted that the man’s older age likely played a role in the PML infection. There have been some reports, although it is rare, of PML in elderly people that may have been exacerbated by an age-related reduction in the production or potency of lymphocytes — cells that attack viruses — in their immune systems. This could result in immunosenescence, an increased susceptibility to infections and disease.

The authors of the JAMA Neurology article noted that clinical trials of Ocrevus were limited to participants ages 18-55, yet the FDA did not set age limits for older people when it approved the medication. Because Ocrevus was the only DMT approved for the treatment of primary progressive MS, the authors believe that many older patients decided to take Ocrevus despite a lack of safety data about its effects on older people with MS.

The authors concluded that, “Ultimately, while age-related immunosenescence and mild lymphopenia may have predisposed the patient to the condition, we believe that ocrelizumab was associated with the development of PML.”  

Should Ocrevus users worry?

I’m not a medical professional, but common sense tells me there’s little need for concern for many of those being treated with Ocrevus. All DMTs that offer significant benefits carry a known risk of severe side effects.

Ocrevus is one of them. Lemtrada (alemtuzumab), which I was treated with when I was 69, is another. Tysabri, the DMT I used for seven years while in my late 50s and early 60s, is another. PML is a known possibility for people treated with Tysabri.

Yet, many thousands of people with MS have been treated with these therapies without contracting PML. Careful monitoring and the use of blood tests and MRIs seem to be key to avoiding it. In Sweden and France, studies report significant drops in PML cases among Tysabri patients enrolled in risk-management programs, as Multiple Sclerosis News Today reported earlier this year. 

So, need we worry about this case of PML? I think not. But we do need to understand the risks versus the benefits of our MS treatments, discuss them with our neurologists, and do our best to minimize those risks.

You’re invited to visit my personal blog at www.themswire.com.


Note: Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The opinions expressed in this column are not those of Multiple Sclerosis News Today or its parent company, BioNews, and are intended to spark discussion about issues pertaining to multiple sclerosis.


Charles Lumia avatar

Charles Lumia

Darn that's sad to hear. RIP to the fellow who passed.

Ocrevus was recommended to me on my last neurology appointment. I'm 36 and not too worried about side effects, I want to be able to walk for as long as possible so it's worth the risk for me.

Ed Tobias avatar

Ed Tobias

Hi Charles,

Good to hear from you.

I think the risk is worth the benefit for most people with MS especially those who are younger, since studies have shown these DMTs work best when started early. I wish you the best.


Dale avatar


I’m 66 and have used ocrevus since it became legal. I have ppms and time has not been good to me. I use a power chair in the house and my wife pushes me when out. Just in the past two months my Trigeminal nerve in my face gives me shooting pains from my jaw to my eye. Not pleasant and has no pattern. Some days totally without it but always reminds me when I go to bed. Drug my Nero is trying has little effect so far. Now there’s PML you’ve got me wondering.

Ed Tobias avatar

Ed Tobias

Hi Dale,

I'm sorry for all of the problems that you've been having. PML is a very infrequent problem for people on MS meds, particularly if they're carefully monitored. If you're wondering about yourself, however, it's certainly worth a conversation with your neuro.


Maxine jackson avatar

Maxine jackson

I just got my 1st infusion today I was a little concern about PML infection because I am positive for JCV wondering if my risk are greater for PML

Ed Tobias avatar

Ed Tobias

Hi Maxine,

Yes, people who are JCV+ are at a greater risk for PML than those who are not. However, as I wrote in my column, the PML risk for people being treated with Ocrevus seems very low...only 10 cases have been reported (as of last December) out of the thousands who've received this treatment.

I hope your Ocrevus treatment works well for you,


Patricia chase avatar

Patricia chase

My jvc test came back slightly positive, slightly, should I worry

Ed Tobias avatar

Ed Tobias

Hi Patricia,

I'm not a medical professional, so you should really ask your neurologist. However, as a patient I can tell you that I was treated with Tysabri - the DMT with the most concern about PML - for about seven years even though I was JCV+. My JCV titer level was carefully monitored and when it rose too high my DMT was changed. Remember, most people are JCV+.


Carol avatar


Please share the acronym for DMT & JCV?
I am an MS patient and I would like to know what it means? Just a regular person’s perspective and just a neurologist?

Ed Tobias avatar

Ed Tobias

Hi Carol,

Sorry, sometimes I forget that not everyone speaks the MS language.

DMT is Disease Modifying Therapy. It refers to one of the more than 20 medications, e.g. Copaxone, Aubagio and Lemtrada, that are used to slow the progress of MS.

JCV is John Cunningham Virus. It's a rare brain disease that can be prompted by a handful of MS DMTs, (as well as by medications for other illnesses).


Sarah avatar


PML is the rare brain disease. JCV is the name of the virus that many people have been exposed to. It can cause PML when the immune system is compromised.


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