Ocrevus vs Kesimpta vs Briumvi: An MS Specialist Compares B-Cell Therapies

If you've been diagnosed with multiple sclerosis and your neurologist has recommended a B-cell therapy, you're likely facing a question that comes up in my office almost daily: should I go with Ocrevus, Kesimpta, or Briumvi? Which one is "best"?

It's a fair question — and an important one. These three medications represent some of the most effective tools we have against MS today. But comparing them can feel overwhelming when you're already processing a diagnosis, learning a new vocabulary of medical terms, and trying to make decisions about your health.

Here's the good news: all three are excellent medications. The differences between them are real, but they're more about how treatment fits into your life than about which one works "better." This guide will walk you through everything you need to know so you can have an informed conversation with your neurologist and feel confident in your choice.

What Are B-Cell Therapies and How Do They Work?

To understand these medications, it helps to know a little about what's happening in your immune system. In MS, certain immune cells mistakenly attack the myelin — the protective insulation around nerve fibers in your brain and spinal cord. This process, called neuroinflammation, is what causes relapses and accumulates damage over time.

B cells are a type of white blood cell that play a central role in this misdirected immune attack. They don't just produce antibodies — they also activate other immune cells and produce inflammatory signals that drive MS disease activity.

Ocrevus, Kesimpta, and Briumvi all work by targeting a protein called CD20 found on the surface of B cells. By depleting these CD20-positive B cells, these medications remove a key driver of MS inflammation. Importantly, they don't wipe out your entire immune system. Other immune cells — including the plasma cells that maintain your existing immunity from past infections and vaccines — are largely spared because they don't carry CD20.

The Three Anti-CD20 Medications for MS

Ocrevus (Ocrelizumab)

Ocrevus was the first anti-CD20 therapy approved specifically for MS, receiving FDA approval in 2017. It was also groundbreaking as the first medication ever approved for primary progressive MS (PPMS) — a milestone for patients with that form of the disease.

How it's given: Ocrevus is administered as an intravenous (IV) infusion at an infusion center. The first dose is split into two infusions given two weeks apart. After that, you receive a single infusion every six months.

Infusion time: Each infusion takes approximately 3.5 hours, plus monitoring time afterward. Some centers offer a shorter 2-hour infusion protocol for patients who have tolerated previous infusions well.

What the trials showed: In the OPERA I and OPERA II clinical trials, Ocrevus reduced relapse rates by 46-47 percent compared to interferon beta-1a (Rebif). It also significantly reduced new MRI lesions and slowed disability progression. In the ORATORIO trial for PPMS, Ocrevus was the first therapy to show a meaningful slowing of disability progression in primary progressive disease.

Kesimpta (Ofatumumab)

Kesimpta received FDA approval in 2020 and introduced a fundamentally different delivery method — self-injection at home, eliminating the need for infusion center visits entirely.

How it's given: Kesimpta is a subcutaneous injection (just under the skin) that you administer yourself at home using a prefilled autoinjector pen, similar to an EpiPen. After an initial loading period of weekly injections for the first three weeks, you transition to one injection per month.

What the trials showed: The ASCLEPIOS I and II trials demonstrated that Kesimpta reduced relapse rates by approximately 50-59 percent compared to teriflunomide (Aubagio). It also showed significant reductions in new and enlarging MRI lesions and gadolinium-enhancing lesions.

When I discuss Kesimpta with my patients, I often emphasize the independence it offers. There are no infusion center appointments to schedule, no IV lines, and no half-day commitments. For patients who travel frequently or prefer to manage their treatment privately, this can be a significant advantage.

Briumvi (Ublituximab)

Briumvi is the newest of the three, approved by the FDA in late 2022. Its key differentiator is a significantly shorter infusion time compared to Ocrevus.

How it's given: Briumvi is an IV infusion. The first infusion is given over approximately 4 hours, followed by a second infusion two weeks later over about 1 hour. After that, subsequent infusions are given every six months and take approximately 1 hour each.

What the trials showed: The ULTIMATE I and II trials showed that Briumvi reduced relapse rates by approximately 59 percent compared to teriflunomide. It also demonstrated significant reductions in MRI lesion activity.

Head-to-Head Comparison

This table summarizes the key differences between all three B-cell therapies. I recommend saving or printing this for reference when discussing options with your neurologist.

Effectiveness: How Do They Compare?

The honest answer is that all three B-cell therapies are highly effective, and there is no convincing evidence that one is meaningfully superior to the others for relapsing MS.

All three have demonstrated:

• Greater than 50% reduction in annualized relapse rates compared to older therapies
• Significant reduction in new and enlarging MRI lesions (often exceeding 90% reduction)
• Slowing of disability progression over the trial periods
• Reduction in gadolinium-enhancing (active inflammatory) lesions on MRI

In my experience, patients on any of these three medications tend to do very well. When I review MRI scans at follow-up visits, the vast majority show stable disease — no new lesions, no active inflammation. Complementary monitoring tools like the neurofilament light chain blood test can provide additional confirmation that treatment is working between scans. That's exactly what we want to see.

The one important distinction is that Ocrevus is the only B-cell therapy FDA approved for primary progressive MS. If you have PPMS rather than relapsing MS, Ocrevus is currently the standard choice in this category.

Side Effects: What to Expect

Infusion-Related Reactions (Ocrevus and Briumvi)

The most common side effect of Ocrevus and Briumvi is an infusion-related reaction, which can include:

• Itching, rash, or hives
• Flushing or feeling warm
• Throat irritation
• Headache
• Nausea or dizziness
• Fatigue
• Low blood pressure or elevated heart rate

These reactions are most common during the first infusion and typically become milder or disappear with subsequent treatments. Pre-medications (corticosteroids, antihistamines, and acetaminophen) are given before each infusion to minimize these reactions.

Injection-Site Reactions (Kesimpta)

With Kesimpta, the most common side effect is a reaction at the injection site — redness, swelling, itching, or mild pain. These are generally mild and resolve on their own within a day or two. Systemic reactions (fever, chills, headache) can occur but are less common than with IV infusions.

Infection Risk (All Three)

Because B-cell therapies reduce part of your immune response, there is an increased risk of infections, particularly:

• Upper respiratory infections (colds, sinus infections)
• Urinary tract infections
• Herpes virus reactivation (cold sores, shingles)

Immunoglobulin Levels Over Time

One consideration that I discuss with every patient starting B-cell therapy is the potential for immunoglobulin (antibody) levels to decrease over time. Immunoglobulins — particularly IgG and IgM — can gradually decline with prolonged B-cell depletion. While most patients maintain adequate levels, some may experience drops that increase infection susceptibility.

This is why regular blood work to monitor immunoglobulin levels is part of the ongoing management plan. If levels drop significantly, we have strategies to address this, including adjusting dosing intervals or, in rare cases, supplementing with immunoglobulin infusions.

Practical Considerations: Choosing What Fits Your Life

Since effectiveness is comparable across all three medications, the decision often comes down to how treatment fits into your daily life. Here are the key factors I walk through with my patients.

Lifestyle and Convenience

Choose an infusion (Ocrevus or Briumvi) if you:

• Prefer a "set it and forget it" approach with treatment only twice a year
• Don't want to think about your medication between appointments
• Are comfortable visiting an infusion center
• Want medical supervision during every dose

Choose self-injection (Kesimpta) if you:

• Prefer managing treatment independently at home
• Travel frequently or have an unpredictable schedule
• Want to avoid infusion center visits
• Are comfortable with self-injection

Choose Briumvi over Ocrevus if you:

• Prefer infusion but want to minimize time at the infusion center
• Have difficulty sitting for 3+ hours
• Value the shorter ~1-hour infusion time

Insurance and Cost

All three medications carry significant list prices, and out-of-pocket costs vary widely depending on your insurance plan. Key considerations:

• Check whether your insurance has a preferred B-cell therapy — some plans favor one over the others
• All three manufacturers offer patient assistance programs and copay support
• For infusion-based therapies, confirm that your insurance covers the infusion center facility fees in addition to the drug cost
• Your neurologist's office can often help navigate insurance approvals and appeals

Switching Between B-Cell Therapies

Switching between Ocrevus, Kesimpta, and Briumvi is generally straightforward because they all target the same protein (CD20). Common reasons for switching include:

• Insurance changes that affect coverage or copay
• Preference for a different delivery method (e.g., moving from infusion to self-injection or vice versa)
• Infusion reactions that don't improve with pre-medication
• Lifestyle changes that make a different option more practical

Your neurologist will typically time the switch based on when your next dose would have been due and may check B-cell levels to confirm appropriate timing. For a broader look at treatment categories, see our guide on MS treatment options.

Pregnancy Planning

If you're considering starting a family, the timing of B-cell therapy is an important conversation to have with your MS specialist. Current guidance generally recommends:

• Discussing family planning before starting B-cell therapy when possible
• Allowing an adequate washout period between the last dose and conception
• Monitoring disease activity during the transition period

Each of the three medications has different recommendations regarding timing around pregnancy. Your neurologist can help you develop a plan that protects both your MS and your pregnancy. For more detail, see our guide on multiple sclerosis and pregnancy.

How to Choose: A Framework

When patients ask me which B-cell therapy I recommend, I walk them through a simple decision framework:

Step 1 — Do you have primary progressive MS? If yes, Ocrevus is currently the only FDA approved B-cell therapy option for PPMS.

Step 2 — Do you prefer infusion or self-injection? This is often the biggest differentiator. Some patients strongly prefer the autonomy of home injection. Others prefer having a healthcare team administer their treatment and don't mind the infusion center visits.

Step 3 — If infusion, does infusion time matter to you? If minimizing time at the infusion center is important, Briumvi's approximately 1-hour infusion (after loading doses) may be preferable to Ocrevus's longer infusion.

Step 4 — What does your neurologist recommend for your specific situation? Your MS specialist knows your disease history, MRI findings, other health conditions, and individual risk factors. Their recommendation accounts for medical nuances that go beyond the general comparison.

Step 5 — What does your insurance cover? Practical reality matters. If one medication has significantly better coverage or lower out-of-pocket costs on your plan, that's a valid and important factor, especially since all three medications work the same way.

When to See Your MS Specialist

If you're currently comparing B-cell therapy options, or if you've already started one and have questions, here are situations where a conversation with your MS specialist is particularly valuable:

• You've been newly diagnosed and want to understand your treatment options
• You're on a B-cell therapy and experiencing side effects you're unsure about
• Your insurance is changing and you need to switch medications
• You're planning a pregnancy and need to discuss timing
• You've noticed new symptoms or are concerned about a possible relapse
• You want a second opinion on your current treatment plan
• You're interested in complementary lifestyle strategies to support your treatment

If you've recently been diagnosed or are still exploring whether your symptoms could be MS, our guide on early signs of multiple sclerosis may also be helpful. And for patients who are uncertain whether their condition is MS or something else, understanding the differences between NMO, MOGAD, and MS is important — particularly because B-cell therapies are also used in NMO spectrum disorder.

At Achilles Neurology Clinic in Beverly Hills and Los Angeles, we specialize in MS care and have extensive experience with all three B-cell therapies. Whether you prefer in-person visits or telehealth consultations, we're here to help you navigate this decision with the personalized attention it deserves.

For patients dealing with the cognitive effects of MS, including brain fog, know that effective disease-modifying therapy is one of the most important steps in protecting your cognitive health long-term.

Frequently Asked Questions

What is the difference between Ocrevus, Kesimpta, and Briumvi?

All three are anti-CD20 B-cell therapies for multiple sclerosis, but they differ in how they are given. Ocrevus (ocrelizumab) and Briumvi (ublituximab) are IV infusions administered every six months at an infusion center. Kesimpta (ofatumumab) is a self-administered subcutaneous injection given monthly at home. Ocrevus is the only one approved for both relapsing MS and primary progressive MS. Briumvi offers a shorter infusion time of about one hour after the initial loading doses.

Which B-cell therapy is most effective for MS?

Clinical trial data shows that all three B-cell therapies — Ocrevus, Kesimpta, and Briumvi — are highly effective at reducing relapses, new MRI lesions, and disability progression. Each demonstrated greater than 50 percent relapse reduction compared to older therapies in their respective trials. No head-to-head trials have directly compared all three, so the choice typically comes down to delivery method, lifestyle preferences, and insurance coverage rather than differences in efficacy.

Is Kesimpta as effective as Ocrevus?

Yes, Kesimpta (ofatumumab) has demonstrated comparable efficacy to Ocrevus (ocrelizumab) in clinical trials, with both showing significant reductions in relapse rates, new MRI lesions, and disability progression. The main difference is convenience: Kesimpta is a monthly self-injection at home, while Ocrevus requires visits to an infusion center every six months. Both target CD20 on B cells and work through the same fundamental mechanism.

What are the side effects of B-cell therapy for MS?

Common side effects of B-cell therapies include infusion-related reactions (for Ocrevus and Briumvi) or injection-site reactions (for Kesimpta), increased risk of upper respiratory and urinary tract infections, and potential decreases in immunoglobulin levels over time. Infusion reactions are most common during the first dose and typically become milder with subsequent treatments. Serious infections are uncommon but require monitoring. Regular blood work helps track immunoglobulin levels and overall immune function.

Can I switch between Ocrevus, Kesimpta, and Briumvi?

Yes, switching between B-cell therapies is possible and sometimes done for practical reasons such as insurance changes, lifestyle preferences, or side effect management. Because all three target CD20 on B cells, the transition is generally straightforward. Your neurologist will determine the appropriate timing based on your last dose and current B-cell levels. Switching should always be done under medical supervision to ensure continuous disease protection.

How do I choose between infusion and injection for MS treatment?

The choice between infusion and injection often comes down to lifestyle and personal preference. Infusions (Ocrevus or Briumvi) mean visiting an infusion center twice a year but having no medication routine between visits. Self-injection (Kesimpta) means monthly injections at home with no infusion center visits. Some patients prefer the simplicity of twice-yearly infusions, while others value the independence of managing treatment at home. Your neurologist can help you weigh these factors along with insurance coverage and any medical considerations specific to your situation.

About the Author

Dr. Achillefs Ntranos MD

Board-Certified Neurologist
Achilles Neurology Clinic

Dr. Achillefs Ntranos MD is a board-certified neurologist and MS specialist known for his thorough evaluations and compassionate approach. Originally from Greece, he trained at Johns Hopkins University and Mount Sinai Hospital before founding Achilles Neurology Clinic in Beverly Hills to deliver comprehensive, patient-centered neurological care. He specializes in MS, autoimmune neurology, neuropathy, headaches, and other neurological disorders, blending research-driven insights with personalized treatment plans.

Learn More About Dr. Ntranos(310) 774-7025

The information in this article is for educational purposes and should not replace individualized medical advice. Always consult with your healthcare provider about your specific situation and treatment options.