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

Ofatumumab is a targeted therapy medication that helps treat certain types of blood cancers and autoimmune conditions. It works by blocking specific proteins on immune cells that contribute to disease progression, offering hope for people with conditions like multiple sclerosis and chronic lymphocytic leukemia.

This medication represents a significant advancement in personalized medicine. Your doctor might recommend ofatumumab when other treatments haven't worked well enough or when you need a more targeted approach to managing your condition.

What is Ofatumumab?

Ofatumumab is a monoclonal antibody medication that targets CD20 proteins found on certain immune cells. Think of it as a highly trained soldier that seeks out and neutralizes specific troublemaker cells in your body.

The medication comes in two forms: intravenous (IV) infusion and subcutaneous injection. Your healthcare team will determine which method works best for your specific condition and treatment plan.

This drug belongs to a class called CD20-directed cytolytic antibodies. It's designed to be precise in its action, focusing only on cells that carry the CD20 protein marker.

What is Ofatumumab Used For?

Ofatumumab treats several serious conditions, with multiple sclerosis and blood cancers being the primary uses. Your doctor prescribes it when your immune system needs targeted intervention to prevent further damage.

For multiple sclerosis, the subcutaneous form helps reduce relapses and slow disease progression. The medication works by preventing certain immune cells from attacking your nervous system.

In blood cancer treatment, particularly chronic lymphocytic leukemia, the IV form targets cancerous B-cells. This helps control the spread of cancer cells throughout your body.

Sometimes doctors use ofatumumab for other autoimmune conditions when traditional treatments haven't provided adequate relief. Your medical team will discuss whether this medication fits your specific situation.

How Does Ofatumumab Work?

Ofatumumab works by attaching to CD20 proteins on the surface of B-cells, which are a type of white blood cell. Once attached, it signals your immune system to destroy these specific cells.

This medication is considered a moderately strong immunosuppressant. It's more targeted than broad-spectrum treatments but still significantly affects your immune system's function.

The drug doesn't affect all immune cells, only those carrying the CD20 marker. This selective approach helps minimize some side effects while maintaining effectiveness against the targeted condition.

After treatment, your body gradually produces new, healthy B-cells to replace the ones that were removed. This process typically takes several months to complete.

How Should I Take Ofatumumab?

The way you take ofatumumab depends entirely on which form your doctor prescribes. IV infusions happen in a clinical setting, while subcutaneous injections can often be done at home after proper training.

For IV treatments, you'll receive the medication through a vein in your arm over several hours. The healthcare team will monitor you closely during and after each infusion to watch for any reactions.

Subcutaneous injections go under the skin, usually in your thigh, abdomen, or upper arm. Your healthcare team will teach you or a family member how to give these injections safely at home.

You don't need to take this medication with food, but staying well-hydrated helps your body process it more effectively. Drink plenty of water before and after each dose.

Before each treatment, let your healthcare team know about any signs of infection, fever, or feeling unwell. They may need to delay your dose if you're fighting an infection.

How Long Should I Take Ofatumumab For?

The duration of ofatumumab treatment varies significantly based on your condition and how well you respond to the medication. Your doctor will create a personalized treatment timeline just for you.

For multiple sclerosis, many people continue subcutaneous injections for years as long as the medication remains effective and well-tolerated. Regular monitoring helps determine if adjustments are needed.

Cancer treatment schedules often involve cycles of treatment followed by rest periods. Your oncologist will explain the specific timeline based on your cancer type and overall health status.

Never stop taking ofatumumab suddenly without discussing it with your healthcare team first. They need to monitor your condition and possibly adjust other treatments when discontinuing this medication.

What Are the Side Effects of Ofatumumab?

Like all medications that affect your immune system, ofatumumab can cause side effects ranging from mild to more serious. Most people tolerate it well, but knowing what to watch for helps you stay safe.

Here are the most common side effects you might experience:

• Injection site reactions like redness, swelling, or mild pain
• Upper respiratory tract infections such as colds or sinus infections
• Headaches that may occur shortly after treatment
• Fatigue or feeling more tired than usual
• Fever or chills, especially with IV infusions
• Nausea or mild stomach upset

These common effects usually improve as your body adjusts to the medication. Your healthcare team can suggest ways to manage any discomfort you experience.

Some people may experience more serious side effects that require immediate medical attention:

• Severe infections due to lowered immune function
• Infusion reactions during IV treatment including difficulty breathing or severe allergic responses
• Hepatitis B reactivation in people with a history of this infection
• Progressive multifocal leukoencephalopathy (PML), a rare but serious brain infection
• Severe skin reactions or unusual rashes
• Significant drops in blood cell counts

While these serious effects are less common, they underscore why regular monitoring is so important during treatment. Your medical team will watch for early signs and respond quickly if needed.

Who Should Not Take Ofatumumab?

Certain people should avoid ofatumumab due to increased risks or potential complications. Your doctor will carefully review your medical history before prescribing this medication.

You should not take ofatumumab if you have an active, severe infection that your body is currently fighting. The medication's immune-suppressing effects could make infections much worse.

People with known allergies to ofatumumab or any of its ingredients should avoid this medication. Your healthcare team will discuss alternative treatments if you have sensitivity concerns.

If you have hepatitis B, your doctor needs to evaluate the risks carefully. Ofatumumab can cause this virus to become active again, potentially leading to serious liver problems.

Pregnant or breastfeeding women require special consideration. The medication can affect developing babies and may pass through breast milk to nursing infants.

People with severely compromised immune systems from other conditions or treatments may not be good candidates for ofatumumab. Your doctor will weigh the benefits against the increased infection risks.

Ofatumumab Brand Names

Ofatumumab is available under different brand names depending on the formulation and intended use. The most common brand names include Kesimpta for subcutaneous injection and Arzerra for intravenous infusion.

Kesimpta is specifically approved for multiple sclerosis treatment and comes in pre-filled injection pens. This formulation is designed for self-administration at home after proper training.

Arzerra is the brand name for the IV formulation used primarily in cancer treatment. This version requires administration in a healthcare facility with appropriate monitoring equipment.

Always use the exact brand and formulation your doctor prescribes. Different formulations aren't interchangeable, even though they contain the same active ingredient.

Ofatumumab Alternatives

Several alternative medications work similarly to ofatumumab, though each has unique characteristics that might make one more suitable for your situation. Your doctor will help you understand which option offers the best balance of effectiveness and safety for your specific condition.

For multiple sclerosis, alternatives include rituximab, ocrelizumab, and alemtuzumab. Each targets the immune system differently and has distinct side effect profiles.

In cancer treatment, other CD20-targeting antibodies like rituximab might be considered. Your oncologist will explain how these alternatives compare in terms of effectiveness and potential risks.

Traditional disease-modifying therapies for multiple sclerosis include interferons and glatiramer acetate. These work through different mechanisms and might be preferred in certain situations.

The choice between alternatives depends on factors like your specific condition, previous treatment responses, other health conditions, and personal preferences about treatment methods.

Is Ofatumumab Better Than Rituximab?

Ofatumumab and rituximab are both CD20-targeting antibodies, but they have important differences that might make one more suitable for your situation. Neither is universally "better" – the choice depends on your specific needs and circumstances.

Ofatumumab may work more effectively in some people who haven't responded well to rituximab. It binds to CD20 proteins more tightly and targets different parts of the protein, potentially offering benefits when rituximab hasn't worked.

For multiple sclerosis specifically, ofatumumab (Kesimpta) offers the convenience of self-injection at home, while rituximab typically requires IV infusion in a clinical setting. This can significantly impact your quality of life and treatment experience.

The side effect profiles are similar but not identical. Some people tolerate one medication better than the other, and your doctor can help predict which might work best for you.

Your medical team will consider your treatment history, lifestyle preferences, and specific condition when recommending between these options. Both medications have proven effectiveness in their approved uses.