It’s common for people with multiple sclerosis (MS) to switch therapies in the quest to reduce flares and slow the progression of the disease. Each disease-modifying therapy (DMT) comes with its own range of potential benefits and side effects. Since every person has a unique response to a DMT — and that can change over time — you may need to reevaluate your MS treatment plan with your health care provider at different points in your journey.

Today there are more DMTs available than ever to treat MS, giving people living with the condition many treatment options. Among these choices, 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 the risks and benefits involved.

What Makes a DMT Highly Effective?

DMTs reduce the activity of MS 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.

Certain DMTs are part of a group of MS medications deemed “highly effective” by researchers based on how they’ve performed in clinical trials compared to other existing treatments. Highly effective DMTs for MS span several drug classes, including sphingosine-1-phosphate (S1P) receptor modulators and anti-CD20 monoclonal antibodies. 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). DMTs that have been categorized as highly effective include:

• Alemtuzumab (Lemtrada)
• Natalizumab (Tysabri)
• Ocrelizumab (Ocrevus)
• Ofatumumab (Kesimpta)
• Ublituximab (Briumvi)

Certain DMTs have been deemed “highly effective” by researchers based on their performance in clinical trials compared to other existing treatments.

Measurements of Effectiveness

Measuring effectiveness is important because it helps physicians 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, doctors monitor the effectiveness of an MS treatment in three main ways. A doctor’s recommendations on whether to continue or switch medications are mostly 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

Your doctor understands how your MS has progressed and how you’ve responded to DMTs, enabling them to recommend the most effective therapy for you if you decide to switch.

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 initially treated their multiple sclerosis with a highly effective DMT reached the goal of no evidence of disease activity (NEDA) after 12 months of treatment.

The earlier someone with MS starts highly effective DMT treatment, the better chance they have to effectively slow their MS progression.

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 began their MS treatment with a moderate-efficacy DMT 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.

Side Effects of Highly Effective DMTs

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

Serious side effects of highly effective DMTs may include:

• Heart problems
• Opportunistic infections (infections that occur more often and are more severe in people with weakened immune systems)
• Cancer
• Eye disease
• Progressive multifocal leukoencephalopathy (a serious brain disease caused by a viral infection)
• Stroke
• Secondary autoimmune disorders
• Cryptococcal meningitis

Weighing Risks and Benefits of Highly Effective DMTs

Like all medications, including 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. Also, an individual’s safety profile may change as they age, develop other health conditions, or experience immune system changes. Researchers have found that the safety risks of certain MS medications are likely to be greater as people age.

Your neurologist will help you weigh the possible side effects of a highly effective DMT against the potential benefit of reduced relapse rate and slower progression of MS.

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 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.

Building a Community

MyMSTeam is the social network for people with multiple sclerosis and their loved ones. On MyMSTeam, more than 217,000 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.