About This Calculator

The Xolair (omalizumab) Dosing Calculator is a clinical support tool designed to determine the appropriate subcutaneous dosage based on the patient's indication, age, body weight, and baseline serum total IgE levels. The calculations adhere to the dosing tables and guidelines provided in the FDA-approved prescribing information. This tool is intended for educational purposes and should not replace clinical judgment or the official product label.

Outputs Explained

After processing the inputs, the calculator provides a clear dosing recommendation, which includes:

• Total Dose: The total amount of omalizumab in milligrams (mg) to be administered at one time.
• Dosing Frequency: The recommended interval between doses, either every 2 weeks (q2w) or every 4 weeks (q4w).
• Administration Details: Confirmation of the subcutaneous injection route and a suggestion for the combination of prefilled syringes (75 mg and 150 mg) to achieve the total dose.
• Dosing Chart Visualization: For applicable indications, a visual table highlights the patient's position based on their weight and IgE level.

How to Use the Calculator

To determine the correct Xolair dosage, follow these steps:

1. Select the Indication: Choose the appropriate condition from the dropdown menu (e.g., Allergic Asthma, CRSwNP, IgE-Mediated Food Allergy, or CSU).
2. Enter Patient Age: Input the patient's age in years to ensure it aligns with the approved age range for the selected indication.
3. Enter Body Weight: For most indications, provide the patient's body weight. You can enter the value in either kilograms (kg) or pounds (lbs).
4. Enter IgE Level: For most indications, input the pre-treatment serum total IgE level, measured in IU/mL.
5. Calculate: Click the ""Calculate Dose"" button to generate the result. The tool will display the recommended dosing regimen or an error message if the inputs are outside the approved ranges.

Note: For Chronic Spontaneous Urticaria (CSU), dosing is not dependent on body weight or IgE levels, so these fields will be hidden.

Dosing Overview

Xolair dosing is indication-specific. For Allergic Asthma, Chronic Rhinosinusitis with Nasal Polyps (CRSwNP), and IgE-Mediated Food Allergy, the dose and frequency are determined by baseline body weight (20 to 150 kg) and serum IgE level (30 to 1500 IU/mL). Doses range from 75 mg to 600 mg administered subcutaneously every 2 or 4 weeks. Doses exceeding 150 mg must be divided across multiple injection sites.

For Chronic Spontaneous Urticaria (CSU), the recommended dose is 150 mg or 300 mg subcutaneously every 4 weeks, irrespective of body weight or IgE level.

Dose Adjustment During Therapy

Dosing for Xolair is based on the pre-treatment IgE level. While total IgE levels often rise during treatment, these changes should not be used for dose determination or adjustment. The patient's therapeutic response should be periodically re-evaluated to determine the need for continued therapy. No dose adjustments are typically recommended based on changes in weight during treatment, but the prescribing information should be consulted if significant weight changes occur.

Missed Dose Protocol

If a patient misses a scheduled dose of Xolair, the dose should be administered as soon as they remember. The subsequent dosing schedule should then be adjusted to maintain the correct interval (e.g., 2 or 4 weeks) from the date of the most recent administration. It is important to consult the full prescribing information for specific guidance on managing therapy interruptions.

Safety Alerts

Frequently Asked Questions

References

1. XOLAIR® (omalizumab) Prescribing Information. Genentech, Inc. and Novartis Pharmaceuticals Corporation. Revised: 02/2024. Accessed via FDA.gov.
2. Drugs@FDA: FDA-Approved Drugs - Xolair (omalizumab). U.S. Food and Drug Administration.
3. Xolair HCP Official Website. Genentech and Novartis.
4. Casale, T. B., Stokes, J. R. (2021). Omalizumab: A review of the first 10 years of clinical experience. The Journal of Allergy and Clinical Immunology: In Practice, 9(1), 85–96.e1.