Soliris (eculizumab)
An approved treatment for Myasthenia Gravis.
The same compound appears under different names depending on the context. Here is how to identify Eculizumab wherever you encounter it, plus the key facts at a glance.
- Generic name
- Eculizumab
- Brand name
- Soliris
- Development code
- h5G1.1
- Drug class
- Complement C5 inhibitor
- Manufacturer
- Alexion / AstraZeneca
- How it's taken
- Given as an intravenous infusion every 2 weeks (after an initial loading phase of weekly infusions for the first month).
The first complement inhibitor approved for generalized myasthenia gravis. Soliris blocks the immune system's complement cascade, which damages the communication between nerves and muscles in MG patients.
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Where Eculizumab fits
Complement inhibitor for generalized myasthenia gravis in AChR-antibody-positive patients. One of several targeted biologics now available, with biosimilars beginning to provide more affordable access.
How Eculizumab works
In anti-AChR antibody-positive myasthenia gravis, the immune system attacks acetylcholine receptors at the neuromuscular junction. Part of this attack involves the complement cascade, a chain reaction of immune proteins that culminates in membrane attack complex (MAC) formation, which destroys the receptor-bearing muscle membrane. Eculizumab blocks C5, stopping this cascade before MAC can form.
Mechanism: Monoclonal antibody that blocks complement protein C5 to prevent immune-mediated destruction at the neuromuscular junction
Side effects and safety
Carries a black box warning for serious meningococcal infections, which can be life-threatening and can happen even in people who have been vaccinated. Patients must complete or update meningococcal vaccination at least 2 weeks before the first dose (unless waiting would be riskier than starting), and should get medical care right away for any signs of meningococcal infection. Because of this risk, Soliris is available only through a restricted safety program called the ULTOMIRIS and SOLIRIS REMS. Common side effects include headache, upper respiratory infections, diarrhea, and nausea. Serious infections can occur due to immune suppression. The label also warns about infusion-related reactions.
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Eculizumab
Given as an intravenous infusion every 2 weeks (after an initial loading phase of weekly infusions for the first month). Each infusion takes about 35 minutes in adults and 1 to 4 hours in children. Requires ongoing meningococcal monitoring and vaccination.
Availability and cost
Approved biosimilars: Bkemv, Epysqli
Anti-C5 complement monoclonal antibody requiring biweekly IV infusions. Originally priced as one of the world's most expensive drugs for ultra-rare diseases; biosimilar competition is now entering the market.
Help paying for Soliris
Pick your insurance to see which help fits. Drugmaker copay cards can't be used with Medicare, Medicaid or TRICARE; charity funds are the usual route there.
- Copay help
Eligible commercially insured patients may pay as little as $0 for SOLIRIS. Must enroll in OneSource. Not for Medicare, Medicaid or other government insurance.
For: private insurance · source - Insurance and case manager help
OneSource provides help navigating health insurance, treatment education, and a local Patient Education Manager.
For: private insurance, Medicare, Medicaid, TRICARE, no insurance, underinsured · source
Good to know: If you have Medicare, Medicaid or other government insurance, OneSource says it can connect you to third-party resources that may help. The Soliris copay program may also help with some infusion costs.
- From a charity · NORD RareCareMyasthenia Gravis Medical Assistance fundOpen
Pays for: Medical and medication costs.
The foundation says: “Accepting new applications and re-enrollments for current year” - From a charity · NORD RareCareMyasthenia Gravis Premium Copay Assistance fundOpen
Pays for: Insurance premiums and copays.
The foundation says: “Accepting new applications and re-enrollments for current year” - From a charity · TotalAssist (formerly PAN Foundation)Myasthenia Gravis fundOpen
Pays for: Out-of-pocket costs for approved medications, up to $10,000 per year. Requires Medicare, Medicaid or TRICARE.
- From a charity · The Assistance FundMyasthenia Gravis fundWaitlist
Pays for: Copays, coinsurance, deductibles and other health-related expenses.
The foundation says: “WAITLIST — Accepting Waitlist Patients. TAF is currently accepting requests to join the enrollment waitlist for this program. Waitlists a…”
Clinical trial results
The REGAIN trial demonstrated significant improvement in MG-ADL scores (daily living activities) versus placebo in anti-AChR antibody-positive gMG patients. The benefit was sustained over long-term open-label extension studies.
Development history
Eculizumab was originally approved in 2007 for paroxysmal nocturnal hemoglobinuria (PNH). The gMG indication was approved in October 2017. Expanded to pediatric gMG (ages 6+) in March 2025. Ravulizumab (Ultomiris) was later developed as a longer-acting successor.
Explore Myasthenia Gravis trials
Other Myasthenia Gravis treatments
Eculizumab in Trial Friend News and Guides
Common questions about Eculizumab
▸What is Eculizumab (Soliris)?
The first complement inhibitor approved for generalized myasthenia gravis. Soliris blocks the immune system's complement cascade, which damages the communication between nerves and muscles in MG patients.
▸How does Eculizumab work?
In anti-AChR antibody-positive myasthenia gravis, the immune system attacks acetylcholine receptors at the neuromuscular junction. Part of this attack involves the complement cascade, a chain reaction of immune proteins that culminates in membrane attack complex (MAC) formation, which destroys the receptor-bearing muscle membrane. Eculizumab blocks C5, stopping this cascade before MAC can form.
▸What are the side effects of Eculizumab?
Carries a black box warning for serious meningococcal infections, which can be life-threatening and can happen even in people who have been vaccinated. Patients must complete or update meningococcal vaccination at least 2 weeks before the first dose (unless waiting would be riskier than starting), and should get medical care right away for any signs of meningococcal infection. Because of this risk, Soliris is available only through a restricted safety program called the ULTOMIRIS and SOLIRIS REMS. Common side effects include headache, upper respiratory infections, diarrhea, and nausea. Serious infections can occur due to immune suppression. The label also warns about infusion-related reactions.
▸How is Eculizumab taken?
Given as an intravenous infusion every 2 weeks (after an initial loading phase of weekly infusions for the first month). Each infusion takes about 35 minutes in adults and 1 to 4 hours in children. Requires ongoing meningococcal monitoring and vaccination.
▸Is Eculizumab FDA approved?
Yes, Eculizumab (Soliris) is FDA approved (2017) for the treatment of Myasthenia Gravis.
▸How does eculizumab work for myasthenia gravis?
In anti-AChR antibody-positive MG, the complement cascade attacks acetylcholine receptors at the neuromuscular junction. Eculizumab blocks complement protein C5, preventing formation of the membrane attack complex that destroys these receptors, thereby improving nerve-to-muscle communication.
▸Why is meningococcal vaccination required before starting Soliris?
Eculizumab carries a black box warning for meningococcal infections because blocking complement C5 impairs the immune system's ability to fight Neisseria meningitidis bacteria. Vaccination must be given at least 2 weeks before starting treatment.
▸How does Soliris compare to Ultomiris for MG?
Both block complement C5, but ravulizumab (Ultomiris) is engineered for a longer half-life, requiring infusions only every 8 weeks versus every 2 weeks for eculizumab (Soliris). Both showed significant improvement in MG daily activities scores.
▸Are biosimilars available for eculizumab?
Yes. Biosimilars including Bkemv and Epysqli have entered the market, providing more affordable alternatives to the original Soliris. For myasthenia gravis, these biosimilars are approved only for adults with anti-AChR antibody-positive gMG, so children ages 6 to 17 would need brand-name Soliris to get eculizumab on-label. Biosimilar competition is helping improve access for MG patients.
▸Is eculizumab approved for pediatric MG?
Yes. The MG indication was expanded to pediatric patients ages 6 and older in March 2025. Eculizumab was originally approved for adult gMG in October 2017.
▸What other conditions is eculizumab approved for?
Eculizumab was originally approved in 2007 for paroxysmal nocturnal hemoglobinuria (PNH). It is also FDA approved for atypical hemolytic uremic syndrome (aHUS) and for neuromyelitis optica spectrum disorder (NMOSD) in adults who are anti-AQP4 antibody positive. The gMG indication was added in 2017.