• Certain disease-modifying treatments (DMTs) for multiple sclerosis (MS) have been classified as ”highly effective” at slowing disease progression and reducing disability.
• Highly effective DMTs also have the potential to cause rare but serious side effects.
• Your doctor can help you weigh potential benefits of highly effective DMTs against your potential risks.

It’s common for people with multiple sclerosis to switch therapies in the quest to manage symptoms and slow progression of the disease. Drugs used to slow the progression of MS are called disease-modifying therapies.

Today there are more DMTs available than ever to treat MS, and people living with the condition have many treatment options. Among these options, certain DMTs have been identified in clinical studies as being ”highly effective.”

Increasingly, doctors are recommending highly effective DMTs as the initial treatment for some people with relapsing forms of MS including relapsing-remitting MS, clinically isolated syndrome (CIS), and active secondary progressive multiple sclerosis (SPMS). Currently, one DMT is approved for people with primary progressive MS.

Since highly effective DMTs can also carry the risk of serious side effects, it’s important to understand all of the risks and benefits involved.

What Makes a DMT Highly Effective?

DMTs slow the progression of MS. They do this by targeting the immune system to reduce its attacks on the central nervous system. MS is considered an autoimmune disease because the body essentially attacks its own nerves and brain cells.

The highly effective DMTs are a group of medications for MS that have been deemed highly effective based on how they’ve performed in clinical trials compared to other existing treatments. Highly effective DMTs include MS medications in several drug classes, including sphingosine-1-phosphate (S1P) receptor modulators and anti-CD20 monoclonal antibodies. Highly effective DMTs in different classes work in different ways to slow the progression of MS.

Examples of Highly Effective DMTs

Many highly effective DMTs are now approved by the U.S. Food and Drug Administration (FDA). Highly effective DMTs currently available include:

• Alemtuzumab (Lemtrada)
• Cladribine (Mavenclad)
• Fingolimod (Gilenya)
• Mitoxantrone (Novantrone)
• Natalizumab (Tysabri)
• Ofatumumab (Kesimpta)
• Ocrelizumab (Ocrevus)
• Ozanimod (Zeposia)
• Rituximab (sold under brand names including Rituxan, MabThera, and Truxima)
• Siponimod (Mayzent)

Measuring Effectiveness

Measuring effectiveness is important because it lets a physician know if a treatment option is working. It also helps classify different prescriptions as being moderately effective, highly effective, etc.

But how is effectiveness measured? Briefly, there are three main ways doctors monitor the effectiveness of an MS treatment. A doctor’s recommendations on whether to continue or switch medications are mainly based on:

• MRI results and lab tests that measure MS disease progression by analyzing lesions in the brain and spinal cord
• The frequency of MS relapses (also called disease flares or MS episodes)
• How disability progresses over time

Because your doctor understands how your MS has progressed and how you’ve responded to DMTs, they can recommend which MS therapy is most likely to be effective for you if you decide to switch.

Read DMTs for MS: 3 Signs It Might Be Switch and What To Know.

The Benefits of Starting a Highly Effective DMT Early

The earlier someone with MS starts highly effective DMT treatment, the greater the likelihood the treatment will effectively slow their MS progression. For instance, a 2021 study found that 68 percent of people who started treatment of multiple sclerosis with a highly effective DMT reached the goal of no evidence of disease activity (NEDA) after 12 months of treatment.

Moreover, 52.4 percent of study participants still had NEDA after 24 months of treatment. This can be compared to 36 percent (after 12 months) and 19.4 percent (after 24 months) of those who started a moderate efficacy DMT as a first drug instead.

Although starting highly effective DMTs earlier is better, your neurologist may not recommend one as a first therapy due to concerns about side effects.

Read Advanced Multiple Sclerosis: 4 Symptoms and 8 Ways To Manage.

Side Effects of Highly Effective DMTs

Unfortunately, highly effective DMTs are sometimes associated with the risk of more serious side effects. It is important to note that some of these side effects occur very rarely. Additionally, each individual has a different risk based on their medical history, inherited risk factors, and overall health. Your doctor is the best person to help you assess your personal risk for each side effect.

More serious adverse side effects of highly effective DMTs can include:

• Heart problems
• Opportunistic infections
• Basal cell carcinoma, a type of skin cancer
• Lymphoma, a type of blood cell cancer
• Eye disease
• Progressive multifocal leukoencephalopathy, a serious brain disease caused by a viral infection
• Posterior reversible encephalopathy, a neurological condition that involves headache, seizures, altered mental status, and vision loss

Weighing Risks and Benefits of Highly Effective DMTs

Like all medications, even those available over the counter, highly effective DMTs have both risks and benefits. Safety concerns should be a key consideration when thinking about switching therapies. Additionally, every individual’s safety profile may change as they age, develop additional health conditions, or experience immune system changes. Researchers have found that the safety risks of certain therapies are likely to be greater as people age.

However, these risks must be carefully weighed against the benefit of reductions in the relapse rate and progression of MS. As immune cells attack the myelin (protective sheathe around nerves) of the brain and spinal cord, new lesions form and may result in worsening MS symptoms, more exacerbations, and disability progression.

Through shared decision-making, you and your doctor will discuss these risks and benefits. Your role is to share your goals, preferences, and priorities for the doctor to take into account.

Read MS DMTs and Washout Periods: 8 Facts To Know.

Building a Community

MyMSTeam is the social network for people with multiple sclerosis and their loved ones. On MyMSTeam, more than 210,000 members come together to ask questions, give advice, and share their stories with others who understand life with multiple sclerosis.

Are you thinking of switching to a highly effective DMT for multiple sclerosis? Share your thoughts and experiences in the comments below, or start a conversation by posting on your Activities page.