Omalizumab

What it is and how it works

Mechanism of Action Asthma, Chronic Rhinosinusitis with Nasal Polyps, and IgE-Mediated Food Allergy Omalizumab inhibits the binding of IgE to the high-affinity IgE receptor (FcεRI) on the surface of mast cells, basophils, and dendritic cells, resulting in FcεRI down-regulation on these cells. In allergic asthmatics, treatment with omalizumab inhibits IgE-mediated inflammation, as evidenced by reduced blood and tissue eosinophils and reduced inflammatory mediators, including IL-4, IL-5, and IL-13. Chronic Spontaneous Urticaria Omalizumab binds to IgE and lowers free IgE levels. Subsequently, IgE receptors (FcεRI) on cells down-regulate.

Mechanism class: IgE-directed Antibody Interactions

Indications

is an anti-IgE antibody indicated for: Moderate to severe persistent asthma in adults and pediatric patients 6 years of age and older with a positive skin test or in vitro reactivity to a perennial aeroallergen and symptoms that are inadequately controlled with inhaled corticosteroids Chronic rhinosinusitis with nasal polyps (CRSwNP) in adult patients 18 years of age and older with inadequate response to nasal corticosteroids, as add-on maintenance treatment IgE-mediated food allergy in adult and pediatric patients aged 1 year and older for the reduction of allergic reactions (Type I), including anaphylaxis, that may occur with accidental exposure to one or more foods. To be used in conjunction with food allergen avoidance Chronic spontaneous urticaria (CSU) in adults and adolescents 12 years of age and older who remain symptomatic despite H1 antihistamine treatment Limitations of Use : Not indicated for acute bronchospasm or status asthmaticus.

Dosage and administration (summary)

For subcutaneous (SC) administration only. ( 2.2 , 2.3 , 2.4 , 2.5 ) See full prescribing information for administration instructions ( 2.6 , 2.7 , 2.8 ). Asthma : XOLAIR 75 to 375 mg SC every 2 or 4 weeks. Determine dose (mg) and dosing frequency by serum total IgE level (IU/mL), measured before the start of treatment, and body weight (kg). See the dose determination charts. Chronic Rhinosinusitis with Nasal Polyps : XOLAIR 75 to 600 mg SC every 2 or 4 weeks. Determine dose (mg) and dosing frequency by serum total IgE level (IU/mL), measured before the start of treatment, and body weight (kg). See the dose determination charts.

Contraindications

is contraindicated in patients with severe hypersensitivity reaction to XOLAIR or any ingredient of XOLAIR . Severe hypersensitivity reaction to XOLAIR or any ingredient of XOLAIR ( 4 , 5.1 )

Warnings and precautions

Anaphylaxis: Initiate XOLAIR therapy in a healthcare setting prepared to manage anaphylaxis which can be life-threatening and observe patients for an appropriate period of time after administration. Malignancy: Malignancies have been observed in clinical studies. Acute Asthma Symptoms: Do not use for the treatment of acute bronchospasm or status asthmaticus. Corticosteroid Reduction: Do not abruptly discontinue corticosteroids upon initiation of XOLAIR therapy.

Pregnancy

Pregnancy Risk Summary A registry study of XOLAIR exposure during pregnancy showed no increase in the rate of major birth defects or miscarriage. There was an increased rate of low birth weight among registry infants compared to infants in the other cohorts, despite average gestational age at birth.

Storage and supply

Storage XOLAIR prefilled syringe and autoinjector should be shipped and stored under refrigerated conditions 2°C to 8°C (36°F to 46°F) in the original carton. Protect from direct sunlight. XOLAIR prefilled syringe and autoinjector can be removed from and placed back in the refrigerator if needed.

Source: Omalizumab (Xolair) — US FDA prescribing information, 2026-08-13, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.