Should I switch to Ocrevus? What really warrants a medication change when you have multiple sclerosis?

Here is My Question:
Ocrevus vs. Avonex? I'm a 62 yr. old female who has taken Avonex for over 20 years. Because of MILD spinal progression and brain atrophy as evidenced between a 2013 MRI and a 2017 MRI, my neurologist wants me to switch to Ocrevus.

My November 2017 MRI shows no active demylenation and I have no clinical symptoms or disability and haven't had any lesions since one showed inactive on my brainstem on the 2013 MRI. My last symptoms of any kind were in 2005- slight arm weakness for a day or so. There's no way to know when the progress began; 2014,2015 etc.?

I'm really concerned about the Ocrevus side effects - PML (I haven't been tested for JC virus yet), upper respiratory infections, cancer, hair loss etc. vs. Avonex side effects.

So my questions are:
Is Ocrevus really that much better than Avonex in stopping the spinal and brain atrophy? 
What really warrants a medication change?
Does mild progression mean a DMT has stopped working?

I'm considering stopping all DMTs at this point. Would appreciate any thoughts. 

Answer:
It is very difficult to answer your question; some of the information you provide is inconsistent; Please clarify the following and I will try to help. The questions I can answer are at the bottom:

1. You mention, “mild spinal progression” and then state that you have experienced no "clinical symptoms or disability” or  new MRI lesions since 2013. If this is the case what makes you or your doctor think there is “mild spinal cord progression” ? Is this statement based only on MRI changes in the spinal cord and, if so, what kind of changes occurred.  It is hard to imagine a person with MS with no new MRI lesions, no symptoms and no disability over a 4 year period (2013 to 2017) who has experienced significant progression of their disease based on qualitative atrophy measures

2. How was the brain atrophy between 2013 and 2017 measured? If this was not done correctly many mistakes can be made. Remember, a healthy person in your age group will experience a decrease in whole brain volume of up to 0.2 % per year (0.8 % over 4 years). This degree of atrophy can be larger in certain regions of the brain. If your doctor’s impression of increased atrophy over 4 years was based solely on qualitative eye-balling your films (and not done with an automated image analysis technique) , then the results are not very accurate of useful.

As for your other questions

1. Ocrelizumab (Ocrevus) like Rituximab is estimated to have a very low risk of PML (less than 1 in 25,000). 
2. JCV antibody status will have nothing to do with risk of PML on Ocrelizumab. As we have discussed many times on this site, JCV index is only associated with risk of PML when treated with Tysabri.
3. Mild clinical progression in your age group could simply be a result of the combined effects of damage from prior MS activity  and normal aging
4. Generally speaking, a DMT change is warranted by new disease activity, defined as new MRI lesions or relapses, or a rapid progression rate
5. If there was a good reason to start a DMT, then there probably is a good reason to continue it. I do not know enough about your case to tell you if there was a good reason for you to start a DMT
6. Stopping a DMT is usually only recommended in people who should not have been placed on a DMT to begin with or in a person (generally over 60 or 65) with fairly longstanding progressive MS with no recent history of disease activity  defined as relapses or new MRI activity

Hope this information helps.

Revere (Rip) Kinkel MD
Professor of Clinical Neurosciences
Director of the Multiple Sclerosis Program
Clinical Neurosciences Director
University of California San Diego