Immune cell inhibitors are medications that put the brakes on your immune cells and stop them from working like they normally do. They help treat relapsing MS (RMS) by targeting the immune cells attacking your myelin sheath.
Typically, immune cells attack foreign substances in your body to help protect you from viruses, bacteria, and other harmful things. When you have MS, these cells attack myelin. By “turning down” the activity of immune cells, immune cell inhibitors prevent this process.
How Do Immune Cell Inhibitors Work?
The exact process immune cell inhibitors use to treat MS depends on their type.
Monoclonal antibodies are lab-made proteins that mimic natural antibodies. Antibodies are proteins your immune system makes to help destroy harmful substances in your body. Because researchers create these monoclonal antibodies to recognize very specific proteins, they can have a very specific effect. Researchers are still studying which exact cells attack myelin so that they can hone in on them. For example, they’ve pinpointed a marker called CD20 on B cells that they think are involved in myelin damage. When monoclonal antibodies “recognize” CD20 on a cell, they attach to it and kill it.
Immunomodulators are medications that modulate, or change, the action of immune cells so they work differently. Researchers don’t fully understand how they work to treat MS, but their main effect seems to be preventing these cells from multiplying. With fewer myelin-attacking immune cells around, less damage happens. One immunomodulator doctors prescribe for MS, mitoxantrone (Novantrone), is in a class of drugs called antineoplastics. It’s a chemotherapy drug that also treats cancer.
Which Immune Cell Inhibitors Are Used to Treat Relapsing MS?
The FDA has approved several medications in the immune cell inhibitor category to treat RMS. There are different kinds of immune cell inhibitors, including:
Immunomodulators
- Glatiramer acetate (Copaxone, Glatopa)
- Teriflunomide (Aubagio)
- Mitoxantrone (Novantrone)
Monoclonal antibodies
- Alemtuzumab (Lemtrada)
- Natalizumab (Tysabri)
- Ocrelizumab (Ocrevus)
- Ofatumumab (Kesimpta)
- Ublituximab (Briumvi)
In August 2023, the FDA approved natalizumab-sztn (Tyruko), which is a biosimilar to natalizumab. A biosimilar is a drug that has a very similar makeup to an already-approved biologic drug. Biosimilar drugs aren’t an exact copy of the biologics they mimic, but they’re close enough that they’re just as safe, work as well, and work in the same way. Often biosimilars are less expensive than biologic drugs.
When Are Immune Cell Inhibitors Prescribed for Relapsing MS?
Doctors consider disease-modifying therapies (DMTs) in general as “first-line” or mainstay treatments for RRMS, clinically isolated syndrome (CIS), and secondary progressive MS (SPMS). Experts recommend starting a DMT as soon as possible after your diagnosis.
To take any DMT, including immune cell inhibitors, your MS has to be active. That means MRI scans show you’re having inflammation, (whether you’re having relapses or not).
Many immune cell inhibitors are effective in treating MS inflammation. The American Academy of Neurology recommends alemtuzumab (Lemtrada) or natalizumab (Tysabri) for people starting on RRMS DMT treatment for the first time.
How Do You Take Immune Cell Inhibitors?
Depending on the type of immune cell inhibitor you take, you’ll get it either through an IV infusion, an injection with a small needle (injector pen), or as a tablet you take by mouth.
Oral medications. To take these medications, you simply swallow a tablet. Although they’re easy to take, some people worry about forgetting and skipping a dose.
Infusions. You may hear infusions also called a “drip.” You’ll go to an infusion center or clinic to get each dose of the medication. It can take some time for the medication to infuse into your body. Some take only an hour, while others take five to six hours or more. You’ll lay on a bed or sit in a chair for the infusion. A nurse or tech will put a needle into a vein in your arm or leg. You don’t need to take infusion doses as often as injections or tablets.
Injections. Injections typically involve using a device that looks like a pen and clicking it against your skin. You won’t see the needle go in. Someone on your MS care team will show you how to do it the first time, and then you’ll take over the medication doses at home.
The dosing schedule below is what experts generally advise for each medication. Your doctor may adjust your dosage based on your needs and how you respond to the drug.
How Effective Are Immune Cell Inhibitors?
On the whole, research shows that infusion DMTs are more effective than ones you take by mouth or inject into your skin or muscle.
Here’s how different immune cell inhibitors rank based on how well they lower relapse rates and inflammation:
A note on mitoxantrone (Novantrone): Although it is effective at lowering relapse rates, doctors don’t prescribe it often for MS because of its potential risks.
Here’s a look at some results immune cell inhibitors have been able to achieve in clinical trials and other studies.
Are Immune Cell Inhibitors Safe?
Like all medications, immune cell inhibitors can come with side effects, and some can be serious.
Of the side effects you may have from these treatments, the most serious include:
- Kidney problems
- Liver problems
- Risk of birth defects in your baby if you’re pregnant
- Severe immune system responses
- Severe infections
- Skin cancer
- Thyroid problems
- Triggering of hepatitis B infection
Both natalizumab (Tysabri) and ocrelizumab (Ocrevus) carry the risk of causing a rare brain infection called progressive multifocal leukoencephalopathy (PML). PML usually leads to death or severe disability over a period of weeks or months.
Black Box Warnings
When a treatment has serious risk, the FDA gives it a “black box” warning.
These immune cell inhibitors have black box warnings:
Alemtuzumab (Lemtrada). This drugcan cause rare but serious cases of stroke and tears in the lining of arteries in the head and neck. These problems can lead to permanent disability or death.
Mitoxantrone (Novantrone). This medicine comes with enough side effects that doctors don’t often prescribe it for MS. Its black box warning notes potential heart problems, bone marrow cancer, and damage to certain sex organs. If you take it or ever have taken it, your doctor will want to examine your heart function yearly.
Teriflunomide (Aubagio). This drug can lead to liver problems and birth defects. If you take it, your doctor will likely do regular tests to check how well your liver is working. Don’t take it if you're pregnant.
What Are Common Side Effects of Immune Cell Inhibitors?
Immune cell inhibitors weaken your immune system. This increases your risk of infection. It’s important you take steps to protect yourself from germs by getting the vaccines you need, washing your hands often, and avoiding people who are sick.
Other common side effects of immune cell inhibitors include:
- Cold symptoms
- Diarrhea
- Dizziness
- Fever
- Flushed cheeks
- Increased temperature
- Insomnia
- Itching
- Hair thinning
- Headache
- Nausea
- Nose and throat swelling
- Numbness/tingling
- Pain
- Reaction at the injection or infusion site
- Vomiting
Be sure you keep your doctor informed about any side effects you start having as you take your treatment. Ask what you should expect with the immune cell inhibitor you choose.
Who Should Not Take Immune Cell Inhibitors?
If you’re considering a monoclonal antibody, your doctor should test you for the John Cunningham (JC) virus antibody. If you test positive, you’re at much higher risk of PML.
If you’re pregnant, breastfeeding, or thinking of getting pregnant, you should have a talk with your doctor about which options are safest and which to avoid. For example, teriflunomide (Aubagio) comes with the risk of causing birth defects if you take it while you’re pregnant, so you should make different choices if you are or could possibly be pregnant while undergoing DMT treatment.
If you’ve had hepatitis B or C, tuberculosis, certain fungal infections, or pneumocystis jiroveci pneumonia (PJP), there’s a chance these infections could come back once you’re on the treatment.
How Much Do Immune Cell Inhibitors Cost?
Immune cell inhibitors are costly, even if you have health insurance. The National MS Society reports that disease-modifying therapies like immune cell inhibitors are the single biggest medical cost for people with MS. These medications can cost anywhere from $57,202 to $92,719, depending on your age and gender.
Your actual out-of-pocket cost for your treatment will depend on factors like your deductible, copays, and your plan's pharmacy coverage. You can call the number on the back of your insurance card to find out the exact amount you’ll pay.
Organizations like NeedyMeds offer diagnosis-based assistance programs for multiple sclerosis, including programs that help with insurance copayments and others that provide assistive equipment for home and bathrooms, as well as mobility devices. You may also qualify for Medicaid, which can help bridge financial gaps in treatment costs.
Patient assistance programs help offset the cost of certain medications if you qualify. You can check the website of any specific program you’re enrolled in for the most current information.
Assistance programs include:
Alemtuzumab (Lemtrada)
Natalizumab (Tysabri)
Ocrelizumab (Ocrevus)
Ofatumumab (Kesimpta)
Ublituximab (Briumvi)
Glatiramer acetate (Copaxone, Glatopa)
Clinical Trials of Immune Cell Inhibitors for Relapsing MS
Clinical trials are research studies that test new medical treatments or procedures in people to find out if they’re safe and effective. Or sometimes they test existing treatments in new ways. Clinical trials need volunteers – real people living with the condition the medications or procedures may treat – in order to get results.
A clinical trial for MS treatments may be an option for you if:
- Treatments you’ve already tried aren’t working
- You’re open to trying new therapies
- You’re interested in being part of research that furthers the treatment of MS
If you take part in a clinical trial, you may see an MS health care team more often than usual.
If you’re interested in joining a clinical trial:
Ask your doctor for next steps. They may know of clinical trials you’d fit into that are currently recruiting new members.
Research options. ClinicalTrials.gov is a database of all U.S. clinical trials. You can search by condition, treatment, location, and other criteria to see if there are any active trials you may qualify for. The National MS Society has a MS-specific list you can filter for MS type and location.
Find out more. If a trial looks right for you, learn about informed consent, how the study is controlled, what the purpose of the study is, whether the treatment has been studied before, and more so you feel ready to make a decision about whether to participate.
What to Know if You’re a Caregiver
When you’re caring for someone with MS, it’s common to be a part of their treatment plan. This may include driving them to infusion appointments, giving injections, or helping them remember to keep oral medications on schedule.
Learn what you can about immune cell inhibitors and other DMTs for MS so you can be an active participant in their decision-making.
Is an Immune Cell Inhibitor Right for Me?
You have an important decision to make when it comes to choosing a treatment for your relapsing MS. Gather the info you need, ask questions, and be a part of the shared decision making.
Consider these factors as you make your treatment selection:
How you take the medication.
You know your lifestyle and habits best. Will a daily pill be easily forgotten? Do you have time in your schedule to spend a day in an infusion chair? Do needles make you squirm? Think through the pros and cons of not only how you’ll take each treatment, but how often. You want the choice that works best for you so you’ll stick to the regimen.
Your other medical conditions
You may be planning to start a family, or you may have other health conditions that would make an immune cell inhibitor a riskier choice. Talk through your family and medical history thoroughly with your doctor.
Cost
Some immune cell inhibitors have assistance programs available; others don’t. A conversation with your health insurance company can give you a better idea of what your out-of-pocket cost may look like with different immune cell inhibitor choices.
Potential side effects
Although you can’t know exactly how a treatment will affect you before you take it, you can review the most common side effects of each treatment to make an informed choice. Some of the more effective IV infusions can come with more serious side effects, so you’ll want to weigh the pros and cons of each with your doctor.
Your MS type
Not all immune cell inhibitors treat all types of relapsing MS. If you have active secondary progressive multiple sclerosis (SPMS) or clinically isolated syndrome (CIS), certain treatments may not be as effective as they would with RRMS. Talk to your doctor about what might work for your MS.