Why Do You Take Ultomiris? Understanding the Long-Acting Treatment

October 11, 2025 •

3 min read

Overactive complement system activity is a primary driver of several rare autoimmune diseases. For individuals with these challenging conditions, understanding why do you take Ultomiris is crucial to managing symptoms, preventing organ damage, and improving quality of life. This long-acting medication specifically targets a key protein in this immune pathway to provide sustained disease control.

Quick Summary

Ultomiris (ravulizumab) is a C5 complement inhibitor prescribed to manage several rare autoimmune and blood-related disorders, including PNH, aHUS, gMG, and NMOSD. By blocking a specific immune protein, it prevents the chronic destruction of healthy body cells and reduces the frequency of symptom flare-ups.

Key Points

Long-acting complement inhibitor: Ultomiris is a long-acting monoclonal antibody that blocks the C5 protein in the immune system's complement cascade to prevent cell damage.
Treats multiple rare diseases: It is used to manage Paroxysmal Nocturnal Hemoglobinuria (PNH), atypical Hemolytic Uremic Syndrome (aHUS), generalized Myasthenia Gravis (gMG), and Neuromyelitis Optica Spectrum Disorder (NMOSD).
Reduces treatment frequency: Compared to its predecessor Soliris, Ultomiris offers a significantly more convenient dosing schedule, with maintenance infusions typically every 8 weeks for adults.
Prevents disease-related damage: By inhibiting the complement system, Ultomiris prevents the chronic hemolysis in PNH, thrombotic microangiopathy in aHUS, and nerve damage in gMG and NMOSD.
Requires specific safety measures: Due to the risk of serious meningococcal infections, patients must be vaccinated and enrolled in the REMS program, and carry a safety card at all times.

What is Ultomiris and How Does It Work?

Ultomiris (ravulizumab) is a long-acting monoclonal antibody that functions as a terminal complement inhibitor. It works by binding to the C5 protein in the complement system, a part of the immune response. While the complement system normally helps fight infections, in certain autoimmune conditions, it mistakenly attacks the body's own healthy cells. By blocking C5, Ultomiris prevents the formation of the membrane attack complex (MAC), which is responsible for cell damage and destruction. This targeted action helps control the abnormal immune response seen in diseases treated with Ultomiris.

Why Do You Take Ultomiris for Specific Conditions?

Ultomiris is prescribed for specific rare conditions where an overactive complement system causes severe damage. The reasons for taking Ultomiris vary depending on the disease:

Paroxysmal Nocturnal Hemoglobinuria (PNH)

In PNH, the complement system attacks red blood cells, causing hemolysis, which can lead to anemia, fatigue, and blood clots. Ultomiris is taken to inhibit this red blood cell destruction, stabilize hemoglobin, reduce transfusions, and lower clot risk.

Atypical Hemolytic Uremic Syndrome (aHUS)

aHUS affects small blood vessels and can cause kidney failure due to complement-driven damage and clot formation. Ultomiris is used to prevent this damage, improve kidney function, potentially eliminate dialysis needs, and normalize blood cell counts.

Generalized Myasthenia Gravis (gMG)

For adults with gMG who have anti-acetylcholine receptor (AChR) antibodies, Ultomiris helps prevent the immune system from attacking nerve-muscle connections. This improves muscle strength and function for daily activities.

Neuromyelitis Optica Spectrum Disorder (NMOSD)

Adults with anti-aquaporin-4 (AQP4) antibody positive NMOSD take Ultomiris to protect the optic nerves and spinal cord from complement-mediated inflammation and damage. This reduces the frequency of symptom flare-ups.

Advantages Over Previous Therapies

Ultomiris is an advancement over therapies like Soliris (eculizumab) for conditions such as PNH and aHUS, primarily due to its longer duration of action.

Comparison of Ultomiris and Soliris


Feature	Ultomiris (ravulizumab)	Soliris (eculizumab)
Mechanism of Action	Long-acting C5 inhibitor	Shorter-acting C5 inhibitor
Dosing Frequency	Maintenance every 8 weeks (adults)	Maintenance every 2 weeks
Half-Life	Longer, lasting up to 4 times longer	Shorter
Treatment Burden	Significantly reduced due to less frequent infusions	Higher due to frequent infusions
Breakthrough Hemolysis (PNH)	Fewer breakthrough events reported in some studies compared to Soliris	More breakthrough events reported in some studies compared to Ultomiris
Administration Options	Intravenous (IV) and subcutaneous (SC) for adults with PNH or aHUS	Intravenous (IV) only

Important Considerations and Safety

Ultomiris can increase the risk of serious meningococcal infections. Patients must receive meningococcal vaccinations before starting treatment and adhere to the ULTOMIRIS and SOLIRIS REMS program. It is crucial to be aware of the symptoms of meningococcal infection and seek immediate medical attention if they occur. Common side effects can include headache, respiratory infections, and gastrointestinal issues.

Conclusion

Patients take Ultomiris to manage rare conditions like PNH, aHUS, gMG, and NMOSD by inhibiting the complement system and preventing cell damage. Its long-lasting effect reduces the frequency of treatment and improves quality of life compared to older options. Adherence to safety protocols, including vaccination and the REMS program, is essential.

Frequently Asked Questions

Ultomiris is approved to treat PNH and aHUS in adults and children one month and older, and anti-AChR antibody-positive gMG and anti-AQP4 antibody-positive NMOSD in adults.

Ultomiris blocks the C5 protein in the complement system, preventing the formation of the membrane attack complex (MAC) and inhibiting the destruction of healthy cells.

Ultomiris has a longer duration of action, typically requiring maintenance doses every 8 weeks for adults, compared to every 2 weeks for Soliris, reducing the treatment burden.

Yes, there is an increased risk of serious meningococcal infections. Patients must be vaccinated and participate in the REMS program.

If a dose is missed, contact your doctor immediately to reschedule, as consistent dosing is important for disease control.

For most conditions like PNH, gMG, and NMOSD, treatment is long-term. For aHUS, the duration is physician-determined and often long-term.

Adults with PNH or aHUS can administer maintenance doses subcutaneously via an on-body injector, and IV infusions may be possible at home with professional assistance.