In 2017, Ocrevus became the first FDA-approved treatment for both relapsing-remitting multiple sclerosis (MS) and primary progressive MS, or PPMS. Integral to its development was Amit Bar-Or, MD, FRCPC, Chief of the Multiple Sclerosis Division at the University of Pennsylvania's Department of Neurology and Director of Penn's Center for Neuroinflammation and Experimental Therapeutics. We sat down with Dr. Bar-Or to talk about the breakthrough treatment and the future of MS.
Q: Dr. Bar-Or, let's start with the basics. What's the difference between relapsing-remitting MS and primary progressive MS?
Relapsing-remitting MS is marked by symptom attacks, better known as relapses, and remissions. It is much more common than PPMS, affecting 85 percent of multiple sclerosis patients.
In relapsing-remitting MS, waves of immune cells activated outside of the central nervous system track in and cause inflammation. Remissions between these attacks can be partial or complete. Inflammation may leave residual damage, even after symptoms disappear. Many patients with relapsing-remitting MS also develop gradually worsening (progressive) MS that can cause ongoing mental and physical deterioration without relapses, referred to as secondary progressive MS. Individuals with PPMS experience the progressive deterioration from the onset, in the absence of clinically evident relapses and remissions.
Where does Ocrevus come in?
By very effectively limiting relapses, Ocrevus can limit the disease's progression in patients with relapsing-remitting MS. Some patients with PPMS, especially early in their course, may have hidden relapses, and Ocrevus may be helpful in limiting their progression. However, Ocrevus doesn't fix anything that's already broken. Ocrevus is likely to be more effective for patients early in the course of PPMS than those who are in the later stages of PPMS.
How does Ocrevus work?
Ocrevus targets and eliminates many B cells that have the CD20 molecule on their surface. By eliminating them, the B cells are less able to overly activate other cells of the immune system and contribute to relapses and damage.
Are there side effects to Ocrevus?
Approximately 30 to 40% of Ocrevus patients experience side effects, but by and large, they are not dangerous. These are typically associated with the infusions themselves and are due to reactions to the death of the CD20-expressing B cells. As the number of B cells drops, side effects fade, too, with subsequent infusions.
Ocrevus marks a significant breakthrough in MS treatment. Are there any recent breakthroughs in MS research?
With relapsing-remitting MS now targeted quite effectively, much of the recent research has focused on better understanding progressive MS. Exciting new insights have been gained into how cells of the central nervous system (microglia and astrocytes) interact with immune cells to contribute to the ongoing injury to the myelin-making cells (the oligodendrocytes) and the nerve cells (the neurons). These insights are starting to translate into new treatment approaches that should hopefully limit or stop these cellular interactions contributing to progressive injury.
Is there anything you'd like to say to someone recently diagnosed with MS?
We are entering an era of “the New MS,” a concept that reflects the availability of growing numbers of increasingly effective therapies. The goal for every newly diagnosed person with MS is to be on a treatment that stops new damage and enables him or her to live their life as though they do not have MS.
Is there anything you'd like to say to someone in the advanced stages of MS?
A major focus in this field is now to better understand progressive MS and develop treatments that will effectively limit progressive injury. Early progress has been slow but is accelerating and one hopes to see breakthroughs in the upcoming years.