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What is Ocrelizumab: Uses, Dosage, Side Effects and More

Created at:1/13/2025

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Ocrelizumab is a prescription medication that helps slow down multiple sclerosis (MS) by targeting specific immune system cells. It's given through an IV infusion at your doctor's office or infusion center, typically every six months after your initial doses.

This medication represents a significant advancement in MS treatment, offering hope for people with both relapsing and primary progressive forms of the disease. Understanding how it works and what to expect can help you feel more confident about your treatment journey.

What is Ocrelizumab?

Ocrelizumab is a monoclonal antibody that specifically targets B cells in your immune system. These B cells play a key role in the autoimmune process that damages nerve fibers in multiple sclerosis.

Think of it as a very precise medication that works like a guided missile, seeking out and binding to specific proteins called CD20 on B cells. Once attached, it helps reduce the number of these cells that can cause inflammation in your nervous system.

The medication belongs to a class called disease-modifying therapies (DMTs), which means it doesn't just treat symptoms but actually works to slow down the progression of MS itself. This makes it quite different from medications that only help with specific symptoms like muscle spasms or fatigue.

What is Ocrelizumab Used For?

Ocrelizumab is FDA-approved for treating two main types of multiple sclerosis. It's the first and only medication approved for primary progressive MS, which makes it particularly valuable for people with this form of the disease.

For relapsing forms of MS, this includes relapsing-remitting MS and active secondary progressive MS. These are the types where people experience clear attacks or relapses followed by periods of recovery or stability.

Your doctor might recommend ocrelizumab if you haven't responded well to other MS treatments, or if you have primary progressive MS where other options are limited. It's also sometimes chosen as a first-line treatment for people with highly active relapsing MS.

How Does Ocrelizumab Work?

Ocrelizumab works by depleting B cells, which are immune cells that contribute to the inflammatory process in MS. This is considered a moderately strong approach to MS treatment, more intensive than some oral medications but less broad than some other infusion therapies.

The medication binds to CD20 proteins on the surface of B cells, marking them for destruction by your immune system. This process significantly reduces the number of B cells circulating in your body for several months.

What makes this approach particularly effective is that it targets the specific immune cells most involved in MS progression while leaving other parts of your immune system relatively intact. The B cell reduction typically lasts for several months, which is why the medication is given every six months.

Within a few weeks of treatment, you'll have significantly fewer B cells in your system. Over time, these cells gradually return, but the medication's effects on slowing MS progression can continue even as B cell numbers recover.

How Should I Take Ocrelizumab?

Ocrelizumab is given only through IV infusion at a medical facility, never at home. Your first dose is typically split into two infusions given two weeks apart, with each infusion taking about 2.5 to 3.5 hours.

Before each infusion, you'll receive pre-medications to help prevent infusion reactions. These usually include an antihistamine like diphenhydramine, a corticosteroid like methylprednisolone, and sometimes acetaminophen. These medications help your body tolerate the infusion better.

You don't need to take ocrelizumab with food since it's given directly into your bloodstream. However, eating a light meal before your infusion appointment can help you feel more comfortable during the lengthy procedure.

During the infusion, medical staff will monitor you closely for any reactions. The medication is given slowly at first, then the rate may be increased if you're tolerating it well. Most people can read, use their phone, or even nap during the infusion.

How Long Should I Take Ocrelizumab For?

Ocrelizumab is typically a long-term treatment that you'll continue as long as it's helping your MS and you're tolerating it well. Most people stay on this medication for years, with regular monitoring to ensure it remains safe and effective.

Your doctor will evaluate your response to treatment every six months, usually around the time of your next infusion. They'll look at factors like new relapses, MRI changes, disability progression, and any side effects you're experiencing.

Some people may need to stop ocrelizumab if they develop serious infections, certain cancers, or severe infusion reactions. Your doctor will discuss these risks with you and monitor for any signs that the medication should be discontinued.

The decision to continue or stop ocrelizumab should always be made together with your MS specialist, weighing the benefits you're receiving against any risks or side effects you're experiencing.

What Are the Side Effects of Ocrelizumab?

Like all medications, ocrelizumab can cause side effects, though many people tolerate it well. The most common side effects are related to the infusion process and increased susceptibility to infections.

Here are the most frequently reported side effects you might experience:

  • Infusion reactions like skin redness, itching, or mild fever during or shortly after treatment
  • Upper respiratory tract infections such as colds or sinus infections
  • Skin infections or oral herpes outbreaks
  • Fatigue that may last for a few days after infusion
  • Headaches or mild body aches
  • Nausea or digestive upset

These common side effects are generally manageable and often improve as your body adjusts to the medication.

More serious but less common side effects require immediate medical attention and include:

  • Severe infusion reactions with difficulty breathing, severe swelling, or chest pain
  • Signs of serious infections like persistent fever, severe fatigue, or unusual symptoms
  • Progressive multifocal leukoencephalopathy (PML), a rare brain infection
  • Hepatitis B reactivation in people with previous exposure
  • Certain types of cancer, particularly breast cancer

Your healthcare team will monitor you carefully for these rare but serious complications through regular blood tests and check-ups.

Who Should Not Take Ocrelizumab?

Ocrelizumab isn't suitable for everyone with MS. Your doctor will carefully review your medical history to determine if this medication is safe for you.

You should not take ocrelizumab if you have an active hepatitis B infection, as the medication can cause this virus to become dangerously active again. You'll need blood tests to check for hepatitis B before starting treatment.

People with active, serious infections should wait until these are fully treated before beginning ocrelizumab. This includes bacterial, viral, or fungal infections that could become worse when your immune system is suppressed.

If you've had severe allergic reactions to ocrelizumab or similar medications in the past, this treatment isn't recommended. Your doctor will discuss alternative options that might be safer for you.

Pregnant women should not receive ocrelizumab, as it can potentially harm the developing baby. If you're planning to become pregnant, discuss this with your doctor well in advance, as the medication can affect your immune system for months after your last dose.

Ocrelizumab Brand Names

Ocrelizumab is sold under the brand name Ocrevus in the United States and most other countries. This is currently the only brand name available, as there are no generic versions of this medication yet.

Ocrevus is manufactured by Genentech in the US and by Roche in other countries. Both companies are part of the same pharmaceutical group, so the medication is essentially identical regardless of where it's produced.

When discussing your treatment with healthcare providers or insurance companies, you may hear both names used interchangeably. Some medical professionals prefer using the generic name (ocrelizumab) while others use the brand name (Ocrevus).

Ocrelizumab Alternatives

Several other medications can treat MS, though the best choice depends on your specific type of MS and individual circumstances. Your doctor will help you weigh the pros and cons of each option.

For relapsing MS, alternatives include oral medications like fingolimod (Gilenya), dimethyl fumarate (Tecfidera), or teriflunomide (Aubagio). These are often easier to take but may be less effective for highly active disease.

Other infusion therapies include natalizumab (Tysabri) and alemtuzumab (Lemtrada), both of which work differently than ocrelizumab. Natalizumab is given monthly, while alemtuzumab involves two treatment courses a year apart.

For primary progressive MS, ocrelizumab is currently the only FDA-approved treatment, making it the gold standard for this form of the disease. However, some doctors may consider off-label use of other medications in specific circumstances.

Is Ocrelizumab Better Than Rituximab?

Ocrelizumab and rituximab are similar medications that both target B cells, but ocrelizumab is specifically designed and approved for MS treatment. Rituximab is primarily used for certain cancers and autoimmune diseases, though some doctors have used it off-label for MS.

Ocrelizumab is considered more refined than rituximab, with modifications that make it potentially safer and more effective for MS. It's designed to be less immunogenic, meaning your body is less likely to develop antibodies against it.

The clinical trial data for ocrelizumab in MS is much more extensive than for rituximab, giving doctors better information about its effectiveness and safety profile. This makes ocrelizumab the preferred choice for most MS specialists.

However, rituximab may sometimes be used if ocrelizumab isn't available or covered by insurance, as the two medications work in very similar ways. Your doctor can help you understand which option might be best for your specific situation.

Frequently asked questions about Ocrelizumab (intravenous route)

Ocrelizumab can generally be used safely in people with heart disease, but your cardiologist and neurologist will need to coordinate your care. The main concern is that infusion reactions could potentially strain your heart.

Before starting treatment, your doctor will evaluate your heart condition and may recommend additional monitoring during infusions. Some people with severe heart problems might need their infusions given more slowly or in a hospital setting rather than an outpatient infusion center.

Contact your doctor's office as soon as you realize you've missed your scheduled infusion appointment. They'll help you reschedule as quickly as possible, ideally within a few weeks of your missed date.

Missing doses can reduce the medication's effectiveness and potentially allow MS activity to return. However, don't panic if you miss an appointment due to illness or other circumstances. Your medical team will work with you to get back on track safely.

Tell your infusion nurse immediately if you experience any concerning symptoms during treatment. Common signs of infusion reactions include skin flushing, itching, difficulty breathing, chest tightness, or feeling faint.

The medical staff is trained to handle these situations and will likely slow or stop the infusion, give you additional medications, and monitor you closely. Most infusion reactions are manageable and don't prevent you from completing treatment, though it may take longer.

The decision to stop ocrelizumab should always be made with your MS specialist, not on your own. There's no predetermined time limit for treatment, as many people benefit from staying on the medication long-term.

Your doctor might recommend stopping if you develop serious side effects, if your MS becomes inactive for an extended period, or if you need to start a family. They'll help you weigh the risks and benefits of continuing versus stopping treatment.

You can receive most vaccinations while on ocrelizumab, but they may be less effective because your immune system is suppressed. Your doctor will recommend completing any needed vaccinations before starting treatment when possible.

Live vaccines should be avoided while taking ocrelizumab, as they could potentially cause infections. This includes vaccines like the live flu vaccine, MMR, and varicella (chickenpox) vaccine. However, inactivated vaccines like the regular flu shot are generally safe and recommended.

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