About this Calculator

This guide provides supporting clinical information for the Xolair Dose Calculator (Urticaria). It details the tool’s inputs, outputs, and key dosing considerations for omalizumab when used for Chronic Spontaneous Urticaria (CSU), based on the official prescribing information.

Outputs

The calculator provides the recommended dosing regimen for Xolair in patients aged 12 years and older with CSU. The primary outputs are:

• Recommended Dose: 150 mg or 300 mg.
• Dosing Frequency: Every 4 weeks.
• Route of Administration: Subcutaneous (SC) injection.
• Key Clinical Note: A reminder that dosing for CSU is determined by the clinician and is not dependent on body weight or baseline serum IgE level, unlike the asthma indication.

How to Use

To operate the calculator, provide the following information:

1. Patient Age: Enter the patient’s age in whole years. The tool will flag if the age is below 12, as this is outside the approved indication for CSU.
2. Diagnosis Confirmation: Check the box to confirm that the indication is Chronic Spontaneous Urticaria (CSU) in a patient who remains symptomatic despite H1-antihistamine treatment.

Dosing Overview

For adults and adolescents (12 years of age and older) with CSU, the approved dose of Xolair is either 150 mg or 300 mg administered via subcutaneous injection every 4 weeks. The appropriate dose is selected by the prescribing clinician. A 300 mg dose should be administered as two separate 150 mg injections to different sites if necessary.

Switching Therapy

This tool does not provide guidance on switching from other therapies to Xolair. If a patient is on corticosteroids, do not abruptly discontinue them upon initiation of Xolair therapy. Taper corticosteroids gradually under the supervision of a physician. Any changes to a patient’s treatment plan should be guided by professional clinical judgment and the official product label.

Missed Dose

If a dose of Xolair for CSU is missed, the patient should be instructed to contact their healthcare provider. The provider will determine the most appropriate time for the next administration and adjust the dosing schedule to maintain a 4-week interval between subsequent injections.

Safety Alerts

Xolair has important warnings and precautions that must be considered before and during treatment. The following is not an exhaustive list:

• BOXED WARNING: Anaphylaxis. Anaphylaxis, which can be life-threatening, has been reported after Xolair administration. It may occur after any dose, even beyond one year of treatment. Administer Xolair in a healthcare setting equipped to manage anaphylaxis.
• Malignancy: Malignant neoplasms were observed in clinical studies.
• Corticosteroid Reduction: Do not stop systemic or inhaled corticosteroids abruptly when starting Xolair.
• Serum Sickness: Signs and symptoms like fever, arthralgia, and rash have been reported.
• Parasitic (Helminth) Infection: Monitor patients at high risk of geohelminth infection.

Frequently Asked Questions

References

This information is based on and should be cross-referenced with official, high-authority sources. Always consult the most current full prescribing information before making any clinical decisions.

1. XOLAIR® (omalizumab) US Prescribing Information. Genentech, Inc. and Novartis Pharmaceuticals Corporation.
2. Xolair for Healthcare Professionals. Genentech USA, Inc.
3. Xolair European public assessment report (EPAR). European Medicines Agency.