Pronunciation: e-que-liz-u-mab
Generic name: eculizumab
Brand names: Soliris, Bkemv, Epysqli
Dosage form: injection for intravenous infusion
Drug class: Selective immunosuppressants

Medically reviewed by Carmen Pope, BPharm. Last updated on Apr 3, 2025.

What is eculizumab?

Eculizumab (brand names Soliris, Bkemv, Epysqli) is used to treat paroxysmal nocturnal hemoglobinuria (PNH) in adults, and a rare chronic blood disease called atypical hemolytic uremic syndrome (aHUS) in adults and children who weigh at least 11 pounds (5 kilograms).

• Eculizumab should not be used to treat aHUS in people with Shiga toxin E. coli-related hemolytic uremic syndrome (STEC-HUS). 

Eculizumab is also used to treat generalized myasthenia gravis (gMG) in adults and children 6 years and older who are anti-acetylcholine receptor (AchR) antibody positive, as well as neuromyelitis optica spectrum disorder (NMOSD) in adults.

Eculizumab's mechanism of action involves binding to a specific protein called complement protein C5 in the blood, preventing it from breaking apart into other proteins that can destroy red blood cells. Eculizumab is used to treat people with genetic conditions that affect the natural defenses of their red blood cells (see How does Soliris work for PNH? for more information).

Eculizumab infusion gained FDA approval on March 16, 2007, for PNH, under the brand name Soliris. Other approvals followed. Bkemv is an interchangeable biosimilar of Soliris, which can be substituted at the pharmacy level, and Epysqli is a biosimilar of Soliris that can be substituted at the prescriber level.

Ultomiris is a longer-acting monoclonal antibody also made by Alexion Pharmaceuticals that may be used to treat PNH, aHUS, gMG, and NMOSD (see How does Ultomiris compare to Soliris for PNH?).

Eculizumab REMS

Eculizumab is available only under a special program called the Ultomiris and Soliris Risk Evaluation and Mitigation Strategy (REMS), Bkemv REMS, or Epysqli REMS. Before you can receive eculizumab, your healthcare provider must:

• enroll in the REMS program
• counsel you about the risk of serious meningococcal infections
• give you information about the signs and symptoms of serious meningococcal infection
• make sure that you are vaccinated against serious infections caused by meningococcal bacteria and that you receive antibiotics if you need to start eculizumab right away and you are not up to date on your vaccines give you a Patient Safety Card about your risk of meningococcal infection, as discussed above.

Eculizumab side effects

The most common side effects of eculizumab are:

• headache, dizziness;

• flu symptoms (fever, tiredness, aches, cough, sore throat);

• runny or stuffy nose, sinus pain;

• painful urination or urinary tract infections;

• nausea, vomiting, diarrhea, stomach pain;

• swelling in your legs or feet;

• bruising;

• muscle or joint pain, back pain;

• a blood cell disorder; or

• high blood pressure.

Serious side effects and warnings

Eculizumab carries a Boxed Warning for serious meningococcal infections.

Meningococcal infections. Eculizumab increases the risk of serious and life-threatening infections caused by meningococcal bacteria (Neisseria meningitidis). Meningococcal infections may quickly become life-threatening or cause death if not recognized and treated early.

• You must complete or update your meningococcal vaccine(s) at least 2 weeks before your first eculizumab infusion.
• If you have not completed your meningococcal vaccines and eculizumab must be started right away, you should receive the required vaccine(s) as soon as possible.
• If you have not been vaccinated and eculizumab must be started right away, you should also receive antibiotics to take for as long as your healthcare provider tells you.
• If you had a meningococcal vaccine in the past, you might need additional vaccines before starting eculizumab. Your healthcare provider will decide if you need additional meningococcal vaccines.
• Meningococcal vaccines do not prevent all meningococcal infections. Call your healthcare provider or get emergency medical care right away if you get any of these signs and symptoms of a serious meningococcal infection:
  • fever
  • fever with a high heart rate
  • headache and fever
  • confusion
  • muscle aches with flu-like symptoms
  • fever and a rash
  • headache with nausea or vomiting
  • headache with a stiff neck or stiff back
  • eyes sensitive to light.

Your healthcare provider will give you a Patient Safety Card about the risk of serious meningococcal infection. Carry it with you at all times during treatment and for 3 months after your last dose of eculizumab. Your risk of 
meningococcal infection may continue for several weeks after your last dose. It is important to show this card to any healthcare provider who treats you. This will help them diagnose and treat you quickly. 

Eculizumab may also increase the risk of other types of serious infections caused by encapsulated bacteria, including Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria gonorrhoeae.

• If your child is treated with eculizumab, your child should receive vaccines against S. pneumoniae and H. influenzae type b (Hib).
• Certain people may be at risk of serious infections with gonorrhea. Talk to your healthcare provider about whether you are at risk for gonorrhea infection, about gonorrhea prevention, and regular testing.
• Certain fungal infections (aspergillus) may also happen if you take eculizumab and have a weak immune system or a low white blood cell count.

Serious infusion-related reactions. Serious infusion-related reactions can happen during your eculizumab infusion. Tell your healthcare provider or nurse right away if you get any of these symptoms during your infusion:

• chest pain
• trouble breathing or shortness of breath
• swelling of your face, tongue, or throat
• feel faint or pass out.

If you have an infusion-related reaction to eculizumab, your healthcare provider may need to infuse it more slowly or stop eculizumab. 

Eculizumab affects your immune system. You may get infections more easily, even serious or fatal infections. Call your doctor right away if you have a headache and fever with nausea or vomiting, skin rash, body aches, flu symptoms, confusion, sensitivity to light, or stiffness in your neck or back.

Do not stop receiving eculizumab without first talking to your doctor. Stopping or interrupting your treatment could cause sudden and serious effects on your red blood cells.

Get emergency medical help if you have signs of an allergic reaction to eculizumab such as hives, chest pain, difficulty breathing, feeling like you might pass out, or swelling of your face, lips, tongue, or throat. These symptoms may occur during the injection.

During or after your treatment with eculizumab, call your doctor at once if you have:

• fever;

• pain or burning when you urinate;

• dangerously high blood pressure - dizziness, weakness, numbness, confusion, blurred vision, vomiting, chest pain, cough, shortness of breath, seizure;

• kidney problems - swelling, urinating less, feeling tired or short of breath;

• signs of a blood cell disorder - pale skin, unusual tiredness, feeling light-headed, cold hands and feet, easy bruising, unusual bleeding, confusion, chest pain, trouble breathing, seizure (convulsions); or

• signs of a blood clot - sudden numbness or weakness, problems with speech or balance, rapid breathing, coughing up blood, pain or swelling in your arms or legs.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Before taking this medicine

You should not use eculizumab if you:

• have a fever or any type of infection

• have not been vaccinated against meningitis

• are pregnant or intending to become pregnant

• are breastfeeding or intending to breastfeed.

Your doctor may recommend certain vaccines. You must be vaccinated against meningococcal infection at least 2 weeks before you start treatment. If you were vaccinated in the past, you may need a booster dose.

Pregnancy

It is not known if eculizumab will harm an unborn baby. Follow your doctor's instructions about using this medicine if you are pregnant. It is very important to control your blood disorder during pregnancy to avoid unwanted effects for you or your baby.

Breastfeeding

Ask a doctor if it is safe to breastfeed while using eculizumab.

How is eculizumab administered?

Eculizumab is injected into a vein by a healthcare provider. The infusion can take at least 35 minutes to complete in adults or 1 to 4 hours in children.

After each infusion, you should be monitored for at least 1 hour for infusion-related reactions.

If you have an infusion-related reaction during your eculizumab infusion, your healthcare provider may decide to give eculizumab more slowly or stop your infusion.

• If you miss an eculizumab infusion, call your healthcare provider right away.

If you have PNH, your healthcare provider will need to monitor you closely for at least 8 weeks after stopping eculizumab. Stopping treatment with eculizumab may cause a breakdown of your red blood cells due to PNH. Symptoms or problems that can happen due to red blood cell breakdown include:

• drop in the number of your red blood
• cell count
• kidney problems
• drop in your platelet
• counts
• blood clots
• confusion
• difficulty breathing
• chest pain.

If you have aHUS, your healthcare provider will need to monitor you closely for at least 12 weeks after stopping eculizumab for signs of worsening aHUS symptoms or problems related to abnormal clotting (thrombotic microangiopathy).

Symptoms or problems that can happen with abnormal clotting may include:

• stroke
• difficulty breathing
• confusion
• kidney problems
• seizure
• swelling in the arms or legs
• chest pain (angina)
• a drop in your platelet count.

Your doctor will perform tests to make sure eculizumab is the right treatment for you.

Do not stop receiving eculizumab without first talking to your doctor. Interrupting your treatment could cause sudden and serious effects on your red blood cells.

Dosing information

Eculizumab is administered as an intravenous infusion over 35 minutes in adults and 1 to 4 hours in children via gravity feed, a syringe-type pump, or an infusion pump.

Usual Adult Dose for Paroxysmal Nocturnal Hemoglobinuria (PNH):

• Eculizumab 600 mg every week for 4 weeks, followed by 900 mg at week 5, then 900 mg every 2 weeks thereafter.

Usual Adult Dose for Atypical Hemolytic Uremic Syndrome (aHUS):

• Eculizumab 900 mg every week for the first 4 weeks, followed by 1200 mg at week 5, then 1200 mg every 2 weeks thereafter.

Usual Adult Dose for Generalized Myasthenia Gravis (gMG):

• Eculizumab 900 mg every week for the first 4 weeks, followed by 1200 mg at week 5, then 1200 mg every 2 weeks thereafter.

Usual Adult Dose for Neuromyelitis Optica Spectrum Disorder (NMOSD):

• Eculizumab 900 mg every week for the first 4 weeks, followed by 1200 mg at week 5, then 1200 mg every 2 weeks thereafter.

Usual Child Dose for Atypical Hemolytic Uremic Syndrome (aHUS) and generalized myasthenia gravis (gMG) in children 6 years and older:

• 5 kg to less than 10 kg: Eculizumab 300 mg single dose at Week 1, followed by 300 mg at week 2, then 300 mg every 3 weeks
• 10 kg to less than 20 kg: Eculizumab 600 mg single dose at Week 1, followed by 300 mg at week 2, then 300 mg every 2 weeks
• 20 kg to less than 30 kg: Eculizumab 600 mg for the first 2 weeks, followed by 600 mg at week 3, then 600 mg every 2 weeks
• 30 kg to less than 40 kg: Eculizumab 600 mg for the first 2 weeks, followed by 900 mg at week 3, then 900 mg every 2 weeks
• 40 kg or greater: Eculizumab 900 mg weekly for the first 4 weeks, followed by 1200 mg at week 5, then 1200 mg every 2 weeks.

What happens if I miss a dose?

Call your doctor for instructions.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using eculizumab?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect eculizumab?

Other drugs may interact with eculizumab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Eculizumab ingredients

Soliris

Active ingredient: eculizumab

Inactive ingredients: polysorbate 80 (vegetable origin), sodium chloride, sodium phosphate dibasic, sodium phosphate monobasic, and Water for Injection.

Bkemv

Active ingredient: eculizumab-aeeb.

Inactive ingredients: sorbitol (E420), acetic acid, polysorbate 80 (vegetable origin), edetate disodium (EDTA), sodium hydroxide may be added to adjust pH, and Water for Injection, USP.

Epysqli

Active ingredient: eculizumab-aagh.

Inactive ingredients: dibasic sodium phosphate, monobasic sodium phosphate, polysorbate 80 (vegetable origin), trehalose, and Water for Injection.

Who makes eculizumab?

Alexion Pharmaceuticals, Inc. manufactures eculizumab under the brand name Soliris.

Amgen Inc. manufactures eculizumab under the brand name Bkemv.

Samsung Bioepsis manufactures eculizumab under the brand name Epysqli.

Eculizumab Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for eculizumab.

Soliris interchangeable products

Interchangeable biosimilar products can be dispensed by a pharmacist without the intervention of the prescriber of the reference product.

Pharmacy laws for biosimilar prescribing may vary by state.

Soliris biosimilar products

Biosimilar products can only be dispensed in place of the reference product if the healthcare provider specifically prescribes the biosimilar product by name.

Pharmacy laws for biosimilar prescribing may vary by state

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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