Disease-modifying therapies (DMTs) are treatments for people with certain types of multiple sclerosis (MS). They target and suppress certain parts of the immune system to prevent MS from worsening.

MS is a neurological disease, which means it affects a person’s nervous system.

This article explores DMTs in further detail, including some examples and their potential side effects and risks. It also discusses other treatments for MS and when to speak with a doctor.

Multiple sclerosis resources

Visit our dedicated hub for more research-backed information and in-depth resources on multiple sclerosis (MS).

Was this helpful?
Older female looking out a windowShare on Pinterest
FG Trade/Getty Images

The immune system is the main defense against infections. However, in people with MS, the immune system targets myelin. This substance coats nerve fibers throughout the body. In MS, the immune system targets the myelin in the brain, spine, and optic nerves.

Myelin damage can cause temporary dysfunction of the nerves and can sometimes cause permanent nerve dysfunction due to scarring.

DMTs alter or suppress specific cells and antibodies of the immune system to prevent it from attacking the myelin sheaths of nerve cells.

The immune system includes white blood cells, which doctors call leukocytes, that travel around a person’s body and attack perceived threats. There are subtypes of leukocytes, such as lymphocytes, which include T cells, B cells, and natural killer cells.

Each DMT works to change or reduce leukocyte activity in very specific ways, and some can include:

  • reducing the population of specific types of leukocytes
  • preventing a subtype of lymphocytes from “switching on”
  • stopping a subtype of lymphocytes from multiplying
  • halting the production of cytokines, which are proteins that drive an inflammatory reaction
  • preventing a subtype of lymphocytes from moving from the blood to the brain

Different types of MS may lead to disabling symptoms that develop in various ways. Relapsing-remitting multiple sclerosis (RRMS), which occurs in the form of attacks and symptom-free periods, is the most common type. Most DMTs can help reduce RRMS attacks and extend symptom-free periods, which doctors may call remission periods.

Certain DMTs have approval from the Food and Drug Administration (FDA) to treat other types of MS, such as secondary progressive MS (SPMS). This type often develops after severe RRMS.

Many DMTs have approval for managing RRMS and work in different ways. For example:

  • Beta interferon drugs: These are proteins that reduce inflammation and regulate immune cells. A person will self-inject these under the skin or into the muscle one or several times per week, depending on the dose.
  • Glatiramer acetate: This is an injected mixture of amino acids, the building blocks of proteins. It can make the immune system less aggressive and balance the amount of immune cells in a person’s body.
  • Teriflunomide: This daily pill helps slow the growth and activity of the immune cells that cause inflammation and nerve damage.
  • Dimethyl fumarate: This pill provides a chemical compound that can lower the levels of substances relating to inflammation. Dimethyl fumarate also makes it harder for the immune cells to enter the brain and nerves. People typically take it twice daily.
  • Fingolimod: This is a daily pill that helps keep immune cells in the lymph nodes. This prevents them from reaching the brain and nerves.
  • Natalizumab: This medication helps stop the immune cells from entering a person’s brain and central nervous system. Doctors administer natalizumab by intravenous infusion every month.

Other types of DMT are also available. For example, siponimod works similarly to fingolimod and has FDA approval for treating SPMS.

A doctor will prescribe these treatments according to the type of MS, the level of severity and disability, and the overall health of an individual. DMTs yield the most long-term benefits for those with early-stage RRMS because they reduce the frequency and severity of relapse. This helps prevent scarring and long-term effects.

DMTs are a class of medications that can interfere with the immune system. As a result, many of these medications reduce the body’s protection against infection.

Some of these infections, such as a brain infection called progressive multifocal leukoencephalopathy (PML), can be dangerous. Natalizumab and fingolimod sometimes increase the risk of PML.

In addition, a 2020 review found that people taking DMTs may face a higher risk of developing COVID-19 than other populations.

Other side effects might include:

However, side effects are usually specific to certain medications. For example, dimethyl fumarate may cause flushing, nausea, and diarrhea. Fingolimod increases the risk of eye problems and a slower heart rate when a person first starts taking the medication.

Some treatments may increase a person’s risk of certain cancers or autoimmune problems. People should make sure to discuss the potential side effects and risks of any medication a doctor prescribes before taking the drug.

Other treatments aim to make relapses less severe and improve recovery. These include:

Not everyone with MS experiences the same symptoms. A doctor can determine the best treatments for managing a person’s particular type of MS.

People who know they have MS should speak with a doctor about any new or bothersome symptoms that are making everyday activities difficult, painful, or uncomfortable. They could mean that a flare-up is occurring.

MS can be progressive, which means it worsens without treatment. Seeking a diagnosis can provide the tools for slowing disease progression and reducing the effects of symptoms on daily life.

DMTs can help reduce how many flare-ups of MS symptoms a person experiences. They do this by blocking parts of the immune system, and it is best to start as soon as possible after receiving an MS diagnosis. However, an individual can start this treatment even if they have late stage MS. Examples of treatments include beta interferon drugs, glatiramer acetate, and natalizumab. However, there are many types of DMTs.

They may increase a person’s risk of infection, and some DMTs can contribute to the risk of cancer and autoimmune disease. Because of this, a doctor will always consider the benefits of DMTs with the possible risks when prescribing treatment.

People should speak with a healthcare professional to learn more about DMTs and other treatment options for MS.