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

If your neurologist has recommended a B-cell therapy for multiple sclerosis, you are probably weighing Ocrevus, Kesimpta, and Briumvi and wondering which is best. It is a fair question, and the honest answer is that all three are highly effective and none has been shown to beat the others. The differences that matter are in how they are given, what that means for your life, and a few specific medical situations. This guide lays those out so you can have a clear conversation with your neurologist.

What are B-cell therapies and how do they work?

In MS, immune cells attack myelin, the insulating coating around nerve fibers in the brain and spinal cord. That process, neuroinflammation, is what causes relapses and accumulates damage over time.

B cells are white blood cells with a central role in that attack. They do more than produce antibodies: they present targets to other immune cells and release inflammatory signals that keep MS active. Ocrevus, Kesimpta, and Briumvi all bind a protein called CD20 on the surface of B cells and remove those cells from circulation. The plasma cells that maintain your existing immunity from past infections and vaccines do not carry CD20 and are largely spared, which is why these medications suppress a specific part of the immune response rather than the whole of it.

The three anti-CD20 medications for MS

Ocrevus (ocrelizumab)

Ocrevus was approved by the FDA in 2017 as the first anti-CD20 therapy for MS and the first medication of any kind for primary progressive MS (PPMS). It is given as an IV infusion at an infusion center every six months; the first treatment is divided into two infusions. A standard infusion takes around three and a half hours plus observation, and a shorter two-hour infusion is available for people who have tolerated earlier doses.

Since September 2024 there is also Ocrevus Zunovo, ocrelizumab combined with hyaluronidase so that it can be given as an under-the-skin injection taking about ten minutes. It is administered by a healthcare professional, not self-injected, still on a twice-a-year schedule, with observation afterward: at least 60 minutes after the first dose and at least 15 minutes after later doses. It is approved for both relapsing MS and PPMS.

In the OPERA I and OPERA II trials, Ocrevus reduced the annual relapse rate by 46 to 47 percent compared with interferon beta-1a, with large reductions in new MRI lesions and a slowing of disability progression. In ORATORIO, it was the first therapy to slow disability progression in PPMS.

Kesimpta (ofatumumab)

Kesimpta was approved in 2020 and changed the delivery model: it is a subcutaneous injection you give yourself at home with a prefilled autoinjector pen. After three weekly starting doses, it is taken once a month. There are no infusion center visits and no IV lines. It is approved for relapsing forms of MS.

In the ASCLEPIOS I and II trials, Kesimpta reduced the annual relapse rate by roughly 50 to 59 percent compared with teriflunomide, with significant reductions in new and enlarging lesions and in contrast-enhancing lesions.

Briumvi (ublituximab)

Briumvi was approved in late 2022. It is an IV infusion given every six months, and its defining feature is speed: after the first treatment, which is divided into a longer and a shorter infusion, each maintenance infusion takes about one hour. It is approved for relapsing forms of MS.

In the ULTIMATE I and II trials, Briumvi reduced the annual relapse rate by 49 to 59 percent compared with teriflunomide, again with large reductions in MRI activity.

Head-to-head comparison

The relapse figures are not directly comparable. Ocrevus was tested against interferon and the other two against teriflunomide, both moderately effective drugs but not the same one. Trial populations also differed. To know which is truly "better" would require head-to-head trials among the three, and none has been done. Real-world comparisons of ocrelizumab and ofatumumab, and network meta-analyses that include ublituximab, suggest similar disease control.

Kesimpta vs Ocrevus

Same target, same class, comparable effectiveness. The choice is between a monthly self-injection at home and a clinic-based treatment twice a year (IV, or the short Zunovo injection). Kesimpta suits people who want independence and no appointments; Ocrevus suits people who prefer not to think about treatment between visits, or who have PPMS.

Briumvi vs Ocrevus

Both are twice-yearly infusions with similar effectiveness and side effects. Briumvi's maintenance infusions take about an hour; Ocrevus's take longer unless the two-hour protocol is used, though Ocrevus Zunovo now offers a ten-minute alternative. Ocrevus is the only one approved for PPMS.

Briumvi vs Kesimpta

Both were tested against teriflunomide with similar results. The difference is delivery: a one-hour infusion every six months versus a monthly injection at home. Neither is approved for PPMS.

Visual guide

Compare delivery and follow-up

• Delivery method: Options include an infusion, a clinician-given injection, or a self-injection.
• Routine: Discuss visit frequency and what the schedule means for you.
• Screening and monitoring: Review safety checks, vaccines, and follow-up with your MS specialist.

Effectiveness: how do they compare?

All three have shown, in their pivotal trials, a roughly 45 to 60 percent reduction in relapse rate compared with an older therapy, reductions in new and enlarging MRI lesions of roughly 77 to 92 percent, near-elimination of contrast-enhancing lesions, and a slowing of disability progression. There is no convincing evidence that one is meaningfully more effective than the others for relapsing MS.

In practice, most people on any of the three have stable follow-up MRI scans with no new lesions. Between scans, the neurofilament light chain blood test can add reassurance that the treatment is controlling inflammation.

The one clear distinction is that Ocrevus is the only B-cell therapy approved for primary progressive MS. For PPMS it is the standard choice in this class.

Side effects: what to expect

Infusion reactions (Ocrevus and Briumvi) and injection reactions (Kesimpta)

The most common side effect of the infusions is an infusion-related reaction: itching, rash, flushing, throat irritation, headache, nausea, fatigue, or changes in blood pressure or heart rate. Reactions are most common with the first infusion and usually become milder or disappear with later ones. Pre-medication with a steroid and an antihistamine, sometimes with acetaminophen as well, is given to reduce them. Ocrevus Zunovo can cause local injection-site reactions and, less often, the same systemic symptoms, which is why observation follows each dose.

With Kesimpta, the usual side effect is redness, swelling, or itching at the injection site, which settles within a day or two. Flu-like symptoms such as fever, chills, and headache can occur, especially with the first injections.

Infection risk (all three)

Because B cells are part of the immune defense, all three raise the risk of infections, most often upper respiratory infections, urinary tract infections, and reactivation of herpes viruses such as cold sores or shingles. Serious infections are uncommon but possible. Fever, a persistent cough, or painful urination should be reported promptly.

Monitoring requirements

Before starting any of the three, you will be screened for hepatitis B, and your vaccination status will be reviewed. Vaccines, including COVID-19, influenza, shingles, and pneumococcal vaccines, work best when completed before treatment, because B-cell depletion blunts the response to them. Live vaccines are avoided during treatment. During treatment, periodic blood work tracks blood counts and immunoglobulin levels. IgG and IgM can gradually fall with prolonged B-cell depletion; most people maintain adequate levels, and if they drop significantly there are strategies to address it, such as adjusting the interval between doses. Monitoring is essentially the same across the three medications.

Visual guide

Prepare for the safety conversation

• Health history: Discuss infections, other conditions, and family plans.
• Screening: Review the blood work needed before treatment.
• Ongoing monitoring: Confirm vaccine planning and the follow-up checks your team recommends.

Practical considerations: choosing what fits your life

Since effectiveness and safety are comparable, the decision usually turns on a short sequence of questions.

1. Do you have primary progressive MS? If so, Ocrevus (IV or Zunovo) is currently the only approved option in this class.
2. Would you rather treat at home or at a clinic? This is the biggest fork. A monthly self-injection means independence, no appointments, and treatment that travels with you, and it suits people who are comfortable with needles and a routine. A clinic-based treatment twice a year means no medication to think about between visits and a healthcare team present for every dose, and it suits people who prefer that structure or want as few reminders of MS as possible.
3. If clinic-based, how much time do you want to spend there? Briumvi's one-hour maintenance infusion and Ocrevus Zunovo's ten-minute injection are both shorter than a standard Ocrevus infusion.
4. What does your insurance cover? All three carry high list prices, and plans often prefer one. Manufacturer copay and assistance programs exist for each, and for infusions the facility fee is billed separately from the drug. Your neurologist's office can help with authorizations and appeals. Coverage is a legitimate deciding factor when the medications work the same way.
5. Are you planning a pregnancy? Timing of anti-CD20 therapy around conception is an important conversation to have before starting, and the approach differs by medication. Our guide to multiple sclerosis and pregnancy covers the principles; the specifics are worked out with your MS specialist.
6. What does your neurologist recommend for you? Your disease history, MRI, other conditions, and prior treatment responses may tip the balance in ways a general comparison cannot capture.

Switching among the three is possible and is sometimes done for insurance, delivery preference, or infusion reactions. Because they share the same target, the transition is usually straightforward, with timing set by your neurologist.

Among these three, there is no wrong choice. What matters most is starting an effective therapy and staying on it consistently. For a wider view of how B-cell therapies compare with other categories, see our guide to choosing an MS medication.

Talking it through with an MS specialist

The comparison above covers what is general. What is specific to you, including your MRI, your relapse history, your other health conditions, your plans, and your coverage, is worked out at a visit. A multiple sclerosis evaluation also arranges the screening blood work and vaccine review that precede any of these therapies, and a second opinion is reasonable if you have been offered one option without discussion of the others. If you are in California, you can request a visit in Beverly Hills or Los Angeles, or by video anywhere in the state.

References

1. Hauser SL, et al. Ocrelizumab versus interferon beta-1a in relapsing multiple sclerosis (OPERA I and II). New England Journal of Medicine, 2017.
2. Hauser SL, et al. Ofatumumab versus teriflunomide in multiple sclerosis (ASCLEPIOS I and II). New England Journal of Medicine, 2020.
3. Steinman L, et al. Ublituximab versus teriflunomide in relapsing multiple sclerosis (ULTIMATE I and II). New England Journal of Medicine, 2022.
4. Genentech. FDA approves Ocrevus Zunovo as the first and only twice-a-year 10-minute subcutaneous injection for relapsing and progressive multiple sclerosis, 2024.
5. National Multiple Sclerosis Society. Disease-modifying therapies for MS.
6. Genentech. OCREVUS (ocrelizumab) prescribing information. DailyMed, US National Library of Medicine.
7. Novartis. KESIMPTA (ofatumumab) prescribing information. DailyMed, US National Library of Medicine.
8. TG Therapeutics. BRIUMVI (ublituximab-xiiy) prescribing information, 2022.
9. Zanghi A, et al. Ocrelizumab and ofatumumab comparison: an Italian real-world propensity score matched study. Journal of Neurology, 2024.
10. Moloney E, et al. Comparative efficacy and tolerability of ublituximab versus other monoclonal antibodies in relapsing multiple sclerosis: a systematic review and network meta-analysis. Frontiers in Neurology, 2024.
11. Rempe T, et al. Ocrelizumab B-cell repopulation-guided extended interval dosing versus standard dosing: similar clinical efficacy with decreased immunoglobulin M deficiency rates. Multiple Sclerosis and Related Disorders, 2023.