When you have multiple sclerosis (MS), your immune system works against you. If left unchecked, immune cells attack the protective layer that surrounds your nerve fibers. Doctors used to think that immune T cells were the main culprit. The immune B cells, which make antibodies, were considered innocent bystanders.
That changed when scientists began to realize that existing multiple sclerosis treatments work in part by changing what B cells do. Can MS be treated by directly targeting B cells?
Doctors already had a way to do this: an antibody-based treatment called rituximab, used to fight a type of cancer called B-cell lymphoma. A 2008 study showed that rituximab helped people with MS. After 48 weeks, the people in the study had fewer brain lesions and also avoided relapses.
The U.S. Food and Drug Administration approved a drug similar to rituximab, called ocrelizumab (Ocrevus), for MS in 2017. You get it through an IV once every 6 months. In 2020, the Food and Drug Administration approved another drug, called ofatumab (Kisembta), that works the same way. Take them in monthly shots at home. Doctors sometimes still use rituximab to treat multiple sclerosis as well.
No matter what type you take, the goal is to reduce your number of B cells. When you work the way you should, you won’t notice anything right away.
“The real benefit we’re looking for isn’t immediate,” says Ari Green, MD, a neurologist at UCSF Health. “It happens over years, if not decades. The goal is to prevent long-term disability.”
When would you consider B-cell therapy?
B-cell therapy prevents disability over time by preventing new damage to your nervous system. It cannot repair damage that is already there, but it can stop future injuries and attacks.
Within the first few months to a year, Green says, you should notice fewer relapses of MS symptoms. The treatment does a better job of preventing the formation of new brain lesions.
So, if you were newly diagnosed, should you take B-cell therapy?
“There is a debate in the MS world about starting someone new with the disease with medications that are considered highly effective versus starting one of the earlier treatments,” says Julie Fayol, a registered nurse and associate vice president of healthcare access. For the National MS Society.
Some doctors may try older medications first to see if they help. This is in part because they have been around for longer, so there is a more comprehensive track record of their safety. If you relapse or get worse, you can move on to B-cell therapy.
It’s a bottom-up approach, says Eric Sechhurst, MD, a neurologist at West Virginia University Hospitals, who has MS and is receiving B-cell therapy himself. “You start with the safest, least effective drug and spread if there is a relapse.”
But he says the newer way to do things is to use the most powerful drugs right from the start. This is what he recommends to his patients and what he chooses for himself. The goal is to prevent disease activity and irreversible damage, and hopefully help prevent disease from getting worse.
“Initiating B-cell therapy first controls disease better and can delay or prevent secondary progression later,” says Seachrist. “But we don’t know the long-term effects on the body from taking ultra-strong immune-modifying drugs.”
While many doctors now recommend a B-cell therapy approach first, there are a few things to consider, Fayol says. Most people do well with B-cell therapy. But since it eliminates part of your immune system, it comes with an increased risk of infection. The treatment also makes any vaccines less effective. Because the drugs have not been around for so long, the effects of B-cell depletion over decades are not yet known.
Fayol says there is no one-size-fits-all approach. She says you should talk to your doctor about the risks and benefits of each option before deciding on MS treatment.
How long will you need B-cell therapy?
It is not yet clear whether or not B-cell therapy will last forever. But doctors have some evidence from its previous use in the treatment of rheumatoid arthritis.
“We know from the arthritic field, that if B cells are depleted for some time and then treatment is stopped, eventually the disease will return,” says Green. “We think this is also true in MS.”
But he says this may only be true if you receive B-cell therapy for a relatively short time. It is not clear what could happen in the long term. Fayol notes that your immune system naturally changes as you age. As a result, MS can become less active over time.
“In most cases of MS, the highest disease activity in terms of inflammatory relapses is early, the first 5 to 10 years or so,” says Seachrist. “So maybe you just need a very strong treatment for a while and then you can ease the tension into something milder on the body. That’s a question in the air.”
Green says that the B-cell treatments available today certainly kill more cells than is necessary to control MS. He expects treatments to become more specific in the future. Some of the therapies now being studied also affect B cells in other, potentially less dangerous ways.
For now, he says, you should expect to use B-cell therapy for years, probably a decade or more. But as doctors learn more and new treatments become available, this may change.
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