ARTICLEMS

The Facts About Disease-Modifying Therapies for MS

By Erica Patino

Reviewed by Adam Kaplin, M.D.

May 10, 2024

Before 30 years ago, a diagnosis of multiple sclerosis (MS) could be grim—there were no approved treatments that could affect the course of the disease, which in its aggressive form can cause symptoms like difficulty walking, talking, and swallowing. But that began to change in 1993, when the Food and Drug Administration (FDA) approved the first disease-modifying therapy (also known as a DMT or disease-modifying drug) for MS.

Now, there are 20 disease-modifying therapies for MS approved by the FDA, plus a few others used off-label. Disease-modifying therapies, as the name suggests, are medications that alter the way MS affects the body.

“Disease-modifying therapies are meant to treat all relapsing forms of MS,” says Kalina Sanders, M.D., a board-certified neurologist at Baptist Neurology Group in Jacksonville Beach, Florida. “They do that by changing, or sometimes suppressing, the immune system.”

This hinders the immune system from attacking the central nervous system—which is what causes the many symptoms of MS. Although all disease-modifying treatments are approved to lessen and ideally prevent relapses, a subset of treatments can prevent or slow progressive loss of neurologic function.

Who Should Take Disease-Modifying Therapies?

Disease-modifying therapies are often prescribed to treat relapsing-remitting MS (RRMS), which affects about 85% of people with MS, according to Sanders. They’re also used to treat clinically isolated syndrome (CIS), which is a similar set of immune-mediated injuries that can occur only once and never come again—but can often be a pre-MS condition that progresses to multiple sclerosis.

These therapies can reduce the number and severity of flares that a person experiences. Slowly eliminating attacks ideally leads to fewer bouts of vision loss and pain, trouble walking, arm numbness, and other symptoms.

Flares are individual attacks on the central nervous system, which includes the brain, optic nerve, and spinal cord, and they’re usually accompanied by areas of attack called lesions that can be seen in a brain MRI (magnetic resonance imaging). Evidence suggests that preventing flares and new lesions early is a critical step in preventing long-term disability and even slowing later progression. That’s why neurologists typically get people with ongoing MS flares and lesions started as soon as possible on a DMT.

On the other hand, progressive forms of MS, which include primary progressive MS (PPMS) and secondary progressive MS (SPMS), can be harder to treat. People with these forms generally don’t get flares but rather experience a gradual worsening of the condition over time.

There is one FDA-approved drug to treat PPMS, called Ocrevus (ocrelizumab), and more may be on the way. “There are a lot of trials going on for other therapies for primary progressive,” says Cori Cummings, M.D., a board-certified neurology resident at the Medical University of South Carolina, in Charleston.

Although disease-modifying therapies can decrease the number of flares a person has, they don’t treat symptoms left over after their recovery from that attack. Other medications are used to treat specific symptoms such as bladder issues, fatigue, depression, and spasticity.

Essentially, anyone who is diagnosed with MS may be a candidate for DMTs. Some are more effective than others, but if a person has a milder form of MS, a lower-efficacy option may be better at reducing the risk of side effects.

Types of Disease-Modifying Therapies

Disease-modifying medications are found in three different forms based on how they’re given:

Injectable DMTs

These drugs are self-injected by a person on either a semiweekly, weekly, or monthly basis.

This category includes the disease-modifying therapies that were some of the earliest approved for treatment of MS, and though they’re known to be very safe, they tend to be lower in efficacy at stopping new attacks compared to more recently approved medications.

Side effects of this class of drugs can include an injection site reaction and flu-like symptoms.

Injectable options include:

Avonex (interferon beta-1a)
Betaseron (interferon beta-1b)
Copaxone (glatiramer acetate)
Extavia (interferon beta-1b)
Glatopa (glatiramer acetate)
Kesimpta (ofatumumab)
Plegridy (peginterferon beta-1a)
Rebif (interferon beta-1a)

Oral DMTs

"Oral medications are commonly used for patients who have a mild to moderate disease burden and don't have a lot of other health issues," Cummings says.

These are pills taken once or twice a day and tend to have moderate efficacy. Side effects can include flu-like symptoms and gastrointestinal issues.

Oral options include:

Aubagio (teriflunomide)
Bafiertam (monomethyl fumarate)
Gilenya (fingolimod)
Mavenclad (cladribine)
Mayzent (siponimod)
Ponvory (ponesimod)
Tecfidera (dimethyl fumarate)
Vumerity (diroximel fumarate)
Zeposia (ozanimod)

Infused DMTs

Most of these medications are administered at an IV infusion center by a trained professional on a monthly or semiyearly basis. “This is probably where we've made some of the biggest gains in the past few years, and most of these are fairly new,” Cummings says.

Infused medications for MS have high efficacy but, as such, can have a greater impact on the immune system, resulting in increased risks for side effects usually related to various types of infections.

IV infusion options include:

Lemtrada (alemtuzumab)
Novantrone (mitoxantrone)
Ocrevus (ocrelizumab)
Rituxan (rituximab)
Tysabri (natalizumab)

Since all disease-modifying therapies alter the immune system, all these options can lower immunity, which may increase the risk for any kind of infection—lower-efficacy drugs will do so less than higher-efficacy ones.

Which DMT Is Best for You?

Knowing which disease-modifying therapy is right for you will be a conversation between you and your neurologist. It’s a shared decision in which your doctor should inform you about your particular risks and benefits, and you should tell them your expectations, goals, and risk tolerance.

Sanders says a lot goes into a doctor’s DMT recommendation. “There's partly science, but mostly art,” she explains. “We look at a person’s MRI features to determine to the best of our ability whether or not they are likely to have more milder disease versus more aggressive disease. Then, based on that, we suggest which type of medication may be best for them.”

Besides efficacy, it's also important to consider a drug’s potential side effects and how or how often it has to be taken. For example, if you think you’ll have a hard time remembering to take a pill twice a day, an injection or infusion might be a better option for you.

Along with making healthy lifestyle choices and managing your symptoms, disease-modifying therapies can help you function and feel your best with MS.

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