About This Calculator

The Ultomiris (ravulizumab) dosing calculator is an informational resource for healthcare professionals to determine appropriate weight-based dosing for patients with Paroxysmal Nocturnal Hemoglobinuria (PNH), Atypical Hemolytic Uremic Syndrome (aHUS), Generalized Myasthenia Gravis (gMG), or Neuromyelitis Optica Spectrum Disorder (NMOSD). It calculates loading, maintenance, and supplemental doses according to the official prescribing information. This tool should not replace clinical judgment.

Understanding the Outputs

The tool provides the following key outputs based on the patient’s weight and selected indication:

• Loading Dose: The initial dose in milligrams (mg) and the corresponding volume in milliliters (mL) to be administered as an intravenous (IV) infusion. This dose establishes therapeutic drug levels.
• Maintenance Dose: The subsequent, recurring dose in mg and mL required to maintain therapeutic levels.
• Dosing Schedule: The recommended interval between maintenance doses, which is either every 4 or 8 weeks depending on patient weight.
• Supplemental Dose: For aHUS patients undergoing plasma exchange (PE), plasmapheresis (PP), or fresh frozen plasma (FFP) infusion, the calculator provides the recommended supplemental dose to be given after each procedure.

How to Use the Calculator

To ensure accurate dose calculation, follow these steps:

1. Select Indication for Use: Choose the appropriate condition (PNH, aHUS, gMG, or NMOSD) from the dropdown menu.
2. Select Patient Population: Indicate whether the patient is an adult or pediatric.
3. Enter Patient Body Weight: Input the patient’s current weight. The tool allows entry in either kilograms (kg) or pounds (lbs), which it will convert automatically.
4. Choose Dosing Phase: Select “Loading Dose” for initial treatment or “Maintenance Dose” for ongoing therapy.
5. (Optional) Calculate Supplemental Dose: For aHUS patients, an option appears to calculate a supplemental dose if they are undergoing plasma exchange. Check this box if applicable.

Dosing Overview

Ultomiris dosing is weight-based. Patients receive an initial IV loading dose, followed by IV maintenance doses two weeks later. The maintenance dosing interval is every 8 weeks for most patients weighing 20 kg or more. For pediatric patients weighing 5 kg to less than 20 kg, the maintenance interval is every 4 weeks. The concentration of ravulizumab for injection is 100 mg/mL.

Switching from Eculizumab

For patients switching from eculizumab (Soliris®) to Ultomiris, the loading dose of Ultomiris should be administered at the time of the next scheduled eculizumab dose. This ensures continuous C5 complement inhibition and a smooth transition between therapies.

Missed Dose Protocol

If a scheduled maintenance dose of Ultomiris is missed, it should be administered as soon as possible. The maintenance dosing schedule should then be re-established from the date of the last administered dose. Patients should be advised to contact their healthcare provider for guidance.

Key Safety Alerts

BOXED WARNING: SERIOUS MENINGOCOCCAL INFECTIONS. Ultomiris, a complement inhibitor, increases the risk of life-threatening meningococcal infections. Patients must be vaccinated with meningococcal vaccines at least 2 weeks prior to the first dose, unless the risks of delaying therapy outweigh the risks of developing an infection. Vaccination reduces, but does not eliminate, the risk. Patients must be monitored for early signs of infection and be enrolled in the ULTOMIRIS REMS program.

Frequently Asked Questions

What is the concentration of Ultomiris used in the calculation?

The calculator uses the standard concentration of Ultomiris for intravenous infusion, which is 100 mg/mL.

How does the calculator handle weights below 5 kg?

Dosing for patients weighing less than 5 kg has not been established in clinical trials. The tool will indicate this and direct you to consult the full prescribing information.

What is the maintenance interval for a 15 kg pediatric patient?

For patients in the 10 kg to less than 20 kg weight band, the maintenance dosing interval is every 4 weeks.

When is a supplemental dose of Ultomiris needed?

A supplemental dose is recommended for aHUS patients following each plasma exchange, plasmapheresis, or fresh frozen plasma infusion to account for drug removal during the procedure.

Can this calculator be used for both adult and pediatric patients?

Yes, the tool is designed to calculate doses for both adult and pediatric patient populations, with different dosing regimens for lower-weight pediatric patients.

What happens if I enter the patient’s weight in pounds (lbs)?

The tool automatically converts the weight from pounds to kilograms (kg) using the standard conversion factor (1 lb = 0.453592 kg) to perform the dose calculation, as dosing is based on kilogram body weight.

How long is the infusion time for Ultomiris?

The minimum infusion time depends on the calculated dose and patient weight. Refer to the specific infusion rate tables in the full prescribing information for detailed administration guidance.

Is a loading dose always required for new patients?

Yes, all patients initiating treatment with Ultomiris require a weight-based loading dose to rapidly achieve therapeutic drug concentrations.

References

1. ULTOMIRIS® (ravulizumab-cwvz) Prescribing Information. U.S. Food and Drug Administration. Accessed August 2024.
2. Ultomiris (ravulizumab) Summary of Product Characteristics. European Medicines Agency. Accessed August 2024.
3. Ultomiris HCP Website. Alexion, AstraZeneca Rare Disease. Accessed August 2024.
4. Meningococcal Disease: Recommendations for Healthcare Professionals. Centers for Disease Control and Prevention (CDC). Accessed August 2024.