What is Ocrevus (Ocrelizumab)?

Living with multiple sclerosis (MS) means navigating a disease that can shift without much warning.

Finding a treatment that works, and that fits into your life, matters enormously. If your neurologist has recommended Ocrevus (ocrelizumab), you’re probably trying to understand exactly what it does, what the infusion process involves, and what to realistically expect.

Ocrevus is an FDA-approved biologic therapy for adults with multiple sclerosis. It targets a specific part of the immune system to reduce the immune attacks that damage nerve fibers in the brain and spinal cord. It’s one of the few treatments approved for relapsing forms of MS and primary progressive MS, which has historically been much harder to treat effectively.

If you’re exploring MS infusion therapy options for the first time, understanding your treatment is a great place to start.

How Ocrevus Works in the Body

Multiple sclerosis is a chronic autoimmune disease where the immune system mistakenly attacks myelin, the protective coating around nerve fibers in the brain and spinal cord. This nerve damage leads to a wide range of symptoms that people with MS experience, from fatigue and mobility challenges to vision changes and cognitive difficulties. In relapsing forms of MS, these attacks cause distinct flare-ups. In primary progressive MS, they drive a gradual, steady worsening.

Ocrevus contains a monoclonal antibody called ocrelizumab that targets a protein called CD20 on the surface of certain B cells. B cells are white blood cells that play a significant role in driving MS-related inflammation. They produce antibodies and release signals that trigger immune attacks on the central nervous system. When Ocrevus (ocrelizumab) enters the bloodstream, it binds to CD20-positive B cells and signals the immune system to remove them from circulation.

This selective approach is meaningfully different from older MS therapies that broadly suppress immune activity. Because Ocrevus (ocrelizumab) focuses on a specific type of immune cell, other parts of the immune system remain largely intact. Clinical trials have demonstrated that patients receiving Ocrevus experienced significantly fewer relapses, less new MRI activity, and slower disability progression compared to other therapies.

Conditions Ocrevus (Ocrelizumab) Is Approved to Treat

Ocrevus (ocrelizumab) is approved for adults with two major categories of multiple sclerosis. Because MS causes different patterns of nerve damage depending on the type, treatment goals vary between them.

Relapsing Forms of Multiple Sclerosis

Ocrevus (ocrelizumab) treats relapsing forms of MS, which include clinically isolated syndrome (CIS), relapsing-remitting MS (RRMS), and active secondary progressive MS. These conditions share a pattern of symptom flare-ups, known as relapses, followed by periods of partial or full recovery.

Patients with relapsing forms of MS who received Ocrevus had significantly fewer relapses than those treated with interferon beta-1a, which is another MS drug used to treat relapsing forms of MS. MRI scans also showed meaningful reductions in new or enlarging brain lesions. For people living with relapsing forms of MS, this kind of disease control can translate directly to greater stability and a better quality of life.

Primary Progressive MS

Primary progressive MS develops differently from relapsing forms. Rather than distinct attacks, symptoms worsen gradually and continuously from the start, without clear periods of recovery. PPMS has historically been very difficult to treat because few medications have shown meaningful benefit.

Ocrevus (ocrelizumab) became the first therapy approved specifically for primary progressive MS. In the ORATORIO trial, it slowed the worsening of disability compared to placebo. While Ocrevus may not stop progression entirely, even modest slowing can make a real difference in preserving independence and daily function over time.

Switching to Ocrevus (Ocrelizumab)

Some people start Ocrevus (ocrelizumab) after trying other MS treatments which haven’t worked well enough or have caused difficult side effects. Switching to Ocrevus is a transition your MS team will plan carefully.

Timing matters: depending on what you were taking before, there may be a period where you don’t take any medications, and your care team will review vaccine status and complete required screening before starting. 

Acelpa Health and its affiliated specialty pharmacies—California Specialty Pharmacy (CSP), ContinuumRx (CRx), Hawaii Specialty Pharmacy (HSP), Continuum Health (CH), and Integrated Care Systems (ICS)—support patients managing complex conditions including MS through every phase of specialty infusion care.

What to Expect During Your Ocrevus (Ocrelizumab) Infusion

Starting a new infusion therapy can feel like a big step, but knowing what to expect can make the process much more manageable. Here’s a clear breakdown of how Ocrevus (ocrelizumab) treatment works and how to prepare.

Your Treatment Schedule

Ocrevus (ocrelizumab) treatment begins with two starter infusions given two weeks apart, each delivering 300 mg of the medication. After completing this initial series, patients receive a single 600 mg infusion every six months as ongoing maintenance. This twice-yearly schedule is one reason many people find Ocrevus manageable long term compared to daily pills or weekly injections required by some other MS treatments.

Ocrevus Zunovo (ocrelizumab and hyaluronidase-ocsq), a subcutaneous injection form of ocrelizumab, is also available as an alternative to the IV infusion for patients who qualify. Rather than a longer IV infusion, eligible patients can receive an under-the-skin injection by their healthcare provider, which can reduce the time commitment of each treatment visit. Your neurologist and care team can help determine which form is right for your situation.

Before Your First Infusion

A few important steps happen before starting Ocrevus (ocrelizumab). Hepatitis B screening is required because Ocrevus can cause hepatitis B virus reactivation in people who carry the virus, even if it was dormant. If testing shows a current or past infection, your medical provider will discuss whether and how to proceed safely.

Vaccine timing is equally important. Because Ocrevus affects immune function, some vaccines are less effective once treatment begins. Healthcare teams recommend completing any needed vaccines at least four to six weeks before the first infusion. Live vaccines should be avoided during treatment and for a period after stopping. Your care team will walk you through exactly what’s needed before you start treatment with Ocrevus.

Managing Infusion Reactions

Infusion reactions are the most common side effects, and they’re most noticeable during the first infusion. Symptoms can include itching, flushing, throat irritation, low blood pressure, mild fever, nausea, or headache. Most symptoms are mild to moderate and occur during the infusion or within 24 hours afterward.

Care teams take proactive steps to reduce reactions. Before each infusion, patients receive premedication, typically a corticosteroid and an antihistamine (like diphenhydramine). The infusion starts slowly, and nurses monitor vital signs throughout. If a reaction occurs, the team can slow or pause the infusion as needed. For patients receiving Ocrevus Zunovo (ocrelizumab and hyaluronidase-ocsq), injection site reactions are possible and should also be discussed with your provider ahead of the first injection.

If you have questions about infusion logistics or what to expect as a new patient, the team at Acelpa Health’s affiliated pharmacies will be there every step of the way.

Side Effects and Safety Considerations

While Ocrevus (ocrelizumab) offers significant benefits for managing MS, it’s important to be aware of possible side effects and safety precautions. Being informed helps care teams and patients stay proactive throughout therapy.

Common Side Effects

Beyond infusion reactions, the most frequently reported side effects include:

• Upper respiratory infections
• Headaches
• Fatigue
• Cold-like symptoms

Most of these symptoms are mild and resolve on their own in time. Because Ocrevus (ocrelizumab) reduces B-cell levels, it can also increase your risk of getting certain infections, so good hygiene and avoiding close contact with sick people are sensible precautions throughout treatment.

It’s worth noting that Ocrevus is not a form of chemotherapy. It is an immunotherapy that selectively targets specific B cells, which is meaningfully different from traditional chemotherapy.

Serious Risks to Know About

Hepatitis B reactivation is a serious concern for anyone with a history of the infection, which is why pre-treatment screening is mandatory, and monitoring continues throughout therapy. If you have a history of hepatitis B, your medical team will monitor you closely.

Progressive multifocal leukoencephalopathy (PML), a rare but serious brain infection, has been reported in patients taking certain immune-modulating therapies. While the risk appears low with Ocrevus (ocrelizumab) based on current data, any new neurological symptoms, including changes in memory, balance, vision, or speech, should be reported to your care team right away. Side effects can also be reported to the FDA at 1-800-FDA-1088.

Pregnancy and Family Planning

Women who could become pregnant should discuss family planning with their provider before starting Ocrevus (ocrelizumab). The medication may harm an unborn baby, and reliable contraception is recommended during treatment and for six months after the last dose. If you become pregnant while receiving Ocrevus (ocrelizumab), contact your healthcare provider immediately.

Babies born to mothers who received Ocrevus (ocrelizumab) during pregnancy may have reduced B-cell levels and should not receive live vaccines until those levels have recovered. If pregnancy is something you’re considering, bring it up with your care team early so you can plan accordingly.

Taking Control of Your MS Treatment

Ocrevus (ocrelizumab) has changed what’s possible for people with MS. For many patients, it represents meaningful progress: fewer relapses, slower disability progression, and a schedule that fits into life without constant disruption. But getting the most from treatment means staying consistent with infusion appointments, communicating openly about any new or changing symptoms, and keeping up with routine monitoring.

Your MS team plays a central role in guiding that process, and so does having a specialty pharmacy that understands the full picture of complex chronic treatment.

Acelpa Health and its affiliated specialty pharmacies work closely alongside patients and their healthcare providers to coordinate every part of the process, from insurance approvals and medication delivery to manufacturer-sponsored and foundation assistance financial coordination and ongoing support. We believe cost should never be a barrier to treatment. Our financial coordinators assess each patient’s individual situation and help explore options to cover medication costs, in accordance with all state, federal, and payor regulations.

Ready to get started or have questions about your Ocrevus treatment? Get in touch with Acelpa Health and its affiliated pharmacies whenever you’re ready to move forward.

Frequently Asked Questions (FAQ):

What is Ocrevus approved to treat?

Ocrevus (ocrelizumab) is FDA-approved for adults with relapsing forms of MS, including clinically isolated syndrome, relapsing-remitting MS, and active secondary progressive MS, as well as primary progressive MS. It was the first therapy ever approved specifically for primary progressive MS.

How does Ocrevus work?

Ocrevus (ocrelizumab) targets CD20-positive B cells, a type of immune cell that plays a key role in driving the inflammation that damages myelin in MS. By reducing the number of these B cells in circulation, it helps lower the frequency of immune attacks on the brain and spinal cord.

What is Ocrevus Zunovo?

Ocrevus Zunovo (ocrelizumab and hyaluronidase-ocsq) is a subcutaneous injection form of ocrelizumab. Rather than an IV infusion at an infusion center, eligible patients can receive it as an under-the-skin injection, which can reduce the overall time commitment of each treatment visit. Your neurologist and care team can help determine whether Ocrevus (ocrelizumab) or Ocrevus Zunovo (ocrelizumab and hyaluronidase-ocsq) is the better option for your situation.

What are the most common side effects of Ocrevus (ocrelizumab)?

Infusion reactions are the most commonly reported side effects, particularly during the first infusion. Symptoms can include itching, flushing, mild fever, nausea, or headache. Upper respiratory infections and fatigue are also commonly reported. Most side effects are mild and manageable with the right preparation and monitoring.

Is Ocrevus a form of chemotherapy?

No. Ocrevus (ocrelizumab) is a monoclonal antibody and is classified as an immunotherapy, not chemotherapy. It selectively targets CD20-positive B cells rather than broadly attacking rapidly dividing cells the way traditional cytotoxic chemotherapy does.