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 practical. Kesimpta is a shot you give yourself at home once a month, while Ocrevus and Briumvi are given at a clinic or infusion center twice a year. Only Ocrevus is approved for primary progressive MS. 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
| Feature | Ocrevus (ocrelizumab) | Kesimpta (ofatumumab) | Briumvi (ublituximab) |
|---|---|---|---|
| How given | IV infusion, or Ocrevus Zunovo under-the-skin injection given by a clinician | Self-injection under the skin at home | IV infusion |
| Frequency | Every 6 months | Monthly, after three weekly starting doses | Every 6 months |
| Time per treatment | About 3.5 hours (2-hour option) for IV; about 10 minutes plus observation for Zunovo | A few minutes | About 1 hour after the first treatment |
| Setting | Infusion center or clinic | Home | Infusion center |
| Approved for relapsing MS | Yes | Yes | Yes |
| Approved for PPMS | Yes | No | No |
| First FDA approval | 2017 (Zunovo 2024) | 2020 | 2022 |
| Relapse reduction in trials | 46 to 47% vs interferon | 50 to 59% vs teriflunomide | 49 to 59% vs teriflunomide |
| Pre-medication | Yes (steroid and antihistamine; acetaminophen optional) | No | Yes (steroid and antihistamine; acetaminophen optional) |
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).
| Feature | Kesimpta (ofatumumab) | Ocrevus (ocrelizumab) |
|---|---|---|
| How given | Self-injection under the skin with a prefilled pen | IV infusion, or the Ocrevus Zunovo injection given by a clinician |
| How often | Monthly, after three weekly starting doses | Every 6 months; the first IV treatment is split into two infusions |
| Where | At home, or wherever you are | Infusion center or clinic |
| Approved for PPMS | No | Yes, as the IV infusion or Zunovo |
| Pre-medication and observation | No pre-medication; the first injection is usually given with a nurse or other clinician guiding you, the rest at home | A steroid and an antihistamine before each dose (acetaminophen optional), then observation |
| Typical reaction | Redness or itching at the injection site; flu-like symptoms with the first injections | Infusion reactions, mostly with the first infusion; injection-site reactions with Zunovo |
| Infections and immunoglobulins | Modestly higher infection risk; immunoglobulin levels checked over time | The same |
| Pregnancy timing | The monthly injections are stopped before trying to conceive, on a timeline your neurologist sets | The twice-yearly dose is timed before trying to conceive, on a timeline your neurologist sets |
| Coverage | Usually through the pharmacy benefit; manufacturer copay program | Usually through the medical benefit, with the facility fee billed separately; manufacturer copay program |
What the real-world data show. No trial has compared the two directly, so the best evidence comes from matched comparisons in routine care. An Italian study matched 216 people on ocrelizumab with 180 on ofatumumab and followed them for about a year. Relapses and new MRI activity were rare in both groups, no one had confirmed disability worsening, and 92 percent on ocrelizumab and 94 percent on ofatumumab had no evidence of disease activity at 12 months, a difference too small to be meaningful (reference 9). One year is short for MS, but so far the two look equally effective.
A much larger comparison followed in 2026. Researchers used two international MS registries to match 5,288 people who started ocrelizumab or ofatumumab between 2021 and 2024 and followed them for a little over a year (reference 12). Both worked very well: relapses were rare on either, about 4 a year for every 100 people on ocrelizumab and 7 on ofatumumab. Ofatumumab did slightly better against slow disability worsening, while ocrelizumab did slightly better against relapses and was more often followed by an improvement in disability; MRI activity and the share of people who stopped treatment did not differ. The authors called the differences modest and advised caution in reading them, so for most people the choice still comes down to how and where they want to be treated.
Who tends to prefer which. Kesimpta tends to suit people who are comfortable with a needle, travel often, live far from an infusion center, or would rather not schedule clinic visits for treatment. Ocrevus tends to suit people who would rather not inject themselves, like having a nurse present for every dose, want to think about treatment only twice a year, or have primary progressive MS.
Briumvi vs Ocrevus
Both are twice-yearly treatments given in a clinic, with similar effectiveness and side effects, and both need pre-medication. The differences are time in the chair, how treatment starts, the trials behind them and approval for PPMS.
| Feature | Briumvi (ublituximab) | Ocrevus (ocrelizumab) |
|---|---|---|
| First treatment | Two infusions two weeks apart, the first one longer | Two IV infusions two weeks apart; Ocrevus Zunovo starts with a single injection |
| Maintenance dose | One infusion every 6 months, about 1 hour | One IV infusion every 6 months, about 3.5 hours (2-hour option), or Ocrevus Zunovo, about 10 minutes plus observation |
| Pre-medication | A steroid and an antihistamine (acetaminophen optional) | The same |
| Approved for PPMS | No | Yes |
| Trial comparator | Teriflunomide (ULTIMATE I and II) | Interferon beta-1a (OPERA I and II) |
| Relapse reduction in trials | 49 to 59% | 46 to 47% |
Why the trial numbers are not a scoreboard. Briumvi was tested against teriflunomide and Ocrevus against interferon beta-1a, so the two relapse figures cannot be compared directly. No trial has put the two side by side. A 2024 network meta-analysis, which compares drugs indirectly through their trials, found no statistically significant difference between ublituximab and ocrelizumab in relapses or disability worsening (reference 10).
Who tends to prefer which. Briumvi tends to suit people who want the shortest infusion without moving to an injection. Ocrevus tends to suit people with primary progressive MS, and people who want the least time in the chair, since an Ocrevus Zunovo injection takes about ten minutes.
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.
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.
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.
- Do you have primary progressive MS? If so, Ocrevus (IV or Zunovo) is currently the only approved option in this class.
- 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.
- 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.
- 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.
- 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.
- 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.
Among these three, there is no wrong choice. What matters most is starting an effective therapy and staying on it consistently.
Switching between them
Switching among the three is possible, and the usual reasons are an insurance change, a preference for home or clinic treatment, or infusion reactions, which a move to Kesimpta's injection avoids. Because all three remove the same B cells, there is usually no washout gap: the new medication typically starts around when the next dose of the old one would have been due, on a timeline your neurologist sets so that protection stays continuous. A new insurance authorization is often needed, so it helps to start that paperwork early.
How the B-cell therapies compare with other options
If you are weighing a B-cell therapy against a different kind of MS medication, this is the short version. The efficacy groupings are broad, not a ranking from head-to-head trials.
| Medication | Route and schedule | Efficacy | Headline monitoring |
|---|---|---|---|
| Ocrevus, Kesimpta, Briumvi (ocrelizumab, ofatumumab, ublituximab) | Infusion or clinician-given injection every 6 months, or a monthly self-injection | High | Hepatitis B screening and a vaccine review before starting; immunoglobulin levels over time |
| Tysabri (natalizumab) | IV infusion every 4 weeks | Very high | JC virus antibody testing, because of the risk of PML, a rare brain infection |
| Vumerity (diroximel fumarate) | Capsules twice a day | Good | Blood counts, especially lymphocytes, and liver tests |
| Mavenclad (cladribine) | Tablets in two short courses a year apart | High | Lymphocyte counts before and after each course |
| Zeposia (ozanimod) | One capsule a day | Good to high | An ECG before starting, plus blood and liver tests and, for some, eye checks |
| Lemtrada (alemtuzumab) | IV infusions in two courses a year apart | Very high | Monthly blood and urine tests for years after the last course, to catch new autoimmune conditions |
For the full range, including the older injectables and how a neurologist narrows the list, see MS treatment options compared.
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. Three good options can still be hard to choose between. In a 60-minute first visit, Dr. Achillefs Ntranos weighs them with you against your MS and your routine. Follow-ups are usually every one to three months and last 30 to 45 minutes. Request a visit in Beverly Hills or Los Angeles, or by video anywhere in California. No referral is needed; the office confirms within 1 business day.
Frequently asked questions
References
- Hauser SL, et al. Ocrelizumab versus interferon beta-1a in relapsing multiple sclerosis (OPERA I and II). New England Journal of Medicine, 2017.
- Hauser SL, et al. Ofatumumab versus teriflunomide in multiple sclerosis (ASCLEPIOS I and II). New England Journal of Medicine, 2020.
- Steinman L, et al. Ublituximab versus teriflunomide in relapsing multiple sclerosis (ULTIMATE I and II). New England Journal of Medicine, 2022.
- Genentech. FDA approves Ocrevus Zunovo as the first and only twice-a-year 10-minute subcutaneous injection for relapsing and progressive multiple sclerosis, 2024.
- National Multiple Sclerosis Society. Disease-modifying therapies for MS.
- Genentech. OCREVUS (ocrelizumab) prescribing information. DailyMed, US National Library of Medicine.
- Novartis. KESIMPTA (ofatumumab) prescribing information. DailyMed, US National Library of Medicine.
- TG Therapeutics. BRIUMVI (ublituximab-xiiy) prescribing information, 2022.
- Zanghi A, et al. Ocrelizumab and ofatumumab comparison: an Italian real-world propensity score matched study. Journal of Neurology, 2024.
- 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.
- 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.
- Zhu C, et al. Comparative effectiveness of ofatumumab and ocrelizumab in relapsing multiple sclerosis: a target trial emulation using multinational registry data. Journal of Neurology, Neurosurgery and Psychiatry, 2026.