About this Calculator

The Omalizumab Dose Calculator is a clinical tool designed to determine the appropriate subcutaneous dosage and administration frequency for omalizumab (Xolair®). It aligns with official prescribing guidelines for approved indications, including moderate to severe persistent allergic asthma, chronic spontaneous urticaria (CSU), and nasal polyps.

Outputs Explained

After entering the required patient data, the calculator provides the following key outputs:

• Total Calculated Dose: The total amount of omalizumab in milligrams (mg) to be administered per session.
• Administration Frequency: The recommended interval between doses, either every 2 or every 4 weeks.
• Vial/Syringe Combination: A suggested combination of 75 mg and/or 150 mg vials or prefilled syringes to achieve the total calculated dose.
• Total Injection Volume: The total volume in milliliters (mL) required for the administration.

How to Use the Calculator

1. Select Indication: Choose the appropriate condition for treatment: Allergic Asthma, Chronic Spontaneous Urticaria (CSU), or Nasal Polyps. The patient’s age must align with the approved range for the indication.
2. Enter Patient Weight: For asthma and nasal polyps, input the patient’s body weight. You can enter the value in kilograms (kg) or pounds (lbs).
3. Enter IgE Level: For asthma and nasal polyps, input the patient’s pre-treatment serum total IgE level, measured in International Units per milliliter (IU/mL).
4. Calculate: The tool will automatically compute the recommended dosing schedule based on the provided inputs and the official dosing tables. For CSU, the dose is fixed and does not require weight or IgE inputs.

Dosing Overview

Omalizumab dosing is indication-specific and administered subcutaneously. For allergic asthma and nasal polyps, the dose is determined by baseline body weight and pre-treatment IgE level. Doses typically range from 75 mg to 375 mg administered every 2 or 4 weeks. For chronic spontaneous urticaria (CSU), dosing is not dependent on weight or IgE levels; the standard dose is 150 mg or 300 mg every 4 weeks.

Switching or Adjusting Therapy

Dose adjustments are generally not recommended without re-evaluating the patient’s condition. The initial dose is based on the pre-treatment IgE level, which can fluctuate during therapy. Any decision to switch from other biologics or adjust the current omalizumab dosing schedule should be made by a qualified healthcare provider based on a comprehensive clinical assessment.

Missed Dose Protocol

If a dose of omalizumab is missed, the patient or caregiver should be instructed to contact their healthcare provider for instructions. The provider will determine the best course of action for scheduling the next administration. Patients should be advised not to administer a double dose to compensate for a missed one.

Safety Alerts

Omalizumab carries a boxed warning for anaphylaxis, a severe, life-threatening allergic reaction. Anaphylaxis can occur after any dose, including the first, or after long-term use. It must be administered in a healthcare setting prepared to manage anaphylaxis. Patients should be observed for an appropriate period after administration.

References

1. XOLAIR® (omalizumab) Prescribing Information. U.S. Food and Drug Administration. Updated February 2024. Accessed August 2024.
2. Xolair HCP Official Website. Genentech, Inc. and Novartis Pharmaceuticals Corporation. Accessed August 2024.
3. Casale TB, Stokes JR. Omalizumab: A review of the first 15 years of clinical use for the treatment of asthma. J Allergy Clin Immunol Pract. 2018;6(5):1484-1493. doi:10.1016/j.jaip.2018.06.012.
4. Maurer M, Rosén K, Hsieh HJ, et al. Omalizumab for the treatment of chronic idiopathic or spontaneous urticaria. N Engl J Med. 2013;368(10):924-935. doi:10.1056/NEJMoa1215372.