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Generic Name: Omalizumab
Class: Respiratory Tract Agents, Miscellaneous
- Antiasthmatic Agents
VA Class: IM600
Chemical Name: Immunoglobulin G, anti-(human immunoglobulin E Fc region) (human-mouse monoclonal E25 clone pSVIE26 γ-chain), disulfide with human-mouse monoclonal E25 clone pSVIE26 κ-chain, dimer
CAS Number: 242138-07-4

Medically reviewed by Last updated on Mar 1, 2019.


  • Anaphylaxis (e.g., bronchospasm, hypotension, syncope, urticaria, angioedema of throat or tongue) reported.1

  • Anaphylaxis can occur after the first or second dose of omalizumab, but may occur after >1 year of therapy.1 Monitor patient for an appropriate period of time following administration.1 (See Medical Personnel and Facilities and also see Sensitivity Reactions under Cautions.)

  • Administer omalizumab in a setting prepared to manage potentially life-threatening anaphylaxis; clinicians administering the drug should be familiar with management of anaphylaxis.1

  • Inform patient of the signs and symptoms of anaphylaxis and instruct patient to obtain immediate medical care should symptoms develop.1


Antiasthmatic and antiallergic agent; a chimeric human-murine (humanized) IgG1κ anti-IgE monoclonal antibody.1 2 3 4

Uses for Xolair

Allergic Asthma

Management of moderate to severe persistent allergic (a positive skin test or in vitro reactivity to a perennial aeroallergen) asthma inadequately controlled with inhaled corticosteroids.1 5 However, some experts reserve use mainly for management of severe allergic asthma.5 10 Manufacturer states that safety and efficacy of omalizumab in the management of other allergic conditions not established; drug not indicated for such conditions.1 Some experts state that omalizumab is effective for the management of concurrent rhinitis.5

In adults and adolescents with severe persistent allergic asthma inadequately controlled with high-dose inhaled corticosteroids and a long-acting β2-adrenergic agonist bronchodilator, some experts recommend addition of omalizumab.10 However, the National Asthma Education and Prevention Program recommends that beneficial effects of long-acting inhaled β2-agonists be weighed carefully against increased risk of severe asthma exacerbations and asthma-related deaths associated with daily use of such agents.10

Not indicated for treatment of acute bronchospasm or status asthmaticus.1

Chronic Idiopathic Urticaria

Treatment of chronic idiopathic urticaria (chronic spontaneous urticaria) in patients who are symptomatic despite antihistamine therapy.1 14 15 16 17

In adults and adolescents with persistent moderate to severe chronic idiopathic urticaria inadequately controlled with antihistamines (at usual and then higher than recommended dosages), some experts recommend addition of omalizumab.17

Not indicated for treatment of other types of urticaria; safety and efficacy for treatment of other types of urticaria not established.1

Xolair Dosage and Administration


    Allergic Asthma
  • If used for extended periods, periodically reassess need for continued therapy based on patient’s asthma severity and degree of asthma control.1 8

  • After treatment interruptions of <1 year, base dosage on serum IgE concentrations obtained prior to treatment initiation.1

  • If omalizumab therapy interrupted for ≥1 year, reevaluate total serum IgE concentrations for dosage determination.1

  • Adjust dosage if patient’s body weight changes substantially; apparent clearance of the drug is proportional to body weight.1 4

    Chronic Idiopathic Urticaria
  • Appropriate duration of therapy not evaluated; periodically reassess need for continued therapy.1

Reduction of Concurrent Inhaled or Systemic Corticosteroid Therapy

  • Do not discontinue abruptly concomitant inhaled or systemic corticosteroid therapy upon initiation of omalizumab therapy in patients with asthma.1 Reduce concomitant corticosteroid dosage gradually (after 16 weeks in clinical trials), and supervise such reduction carefully.1 4

  • Concomitant use of omalizumab with corticosteroids or other immunosuppressive therapies in patients with chronic idiopathic urticaria not studied to date.1


Sub-Q Administration

Allergic asthma: Administer once every 2 or 4 weeks by a clinician.1 8

Chronic idiopathic urticaria: Administer once every 4 weeks by a clinician.1

Clinicians administering the drug need to be familiar with management of anaphylaxis.1 (See Medical Personnel and Facilities under Cautions.)

Administer ≤150 mg per injection site; divide doses >150 mg and inject at various sites.1 10 Entire contents of reconstituted vial must be withdrawn into syringe to obtain total 1.2-mL (150-mg) dose.1


Determine number of vials needed to deliver dose.1

Reconstitute vial containing 202.5 mg of omalizumab lyophilized powder with 1.4 mL of sterile water for injection to provide a solution containing 150 mg per 1.2 mL.1

Swirl vial gently for approximately 1 minute to wet the lyophilized powder and then for 5–10 seconds approximately every 5 minutes to dissolve (generally takes 15–20 minutes) any remaining solids.1 Do not shake vial.1

If >20 minutes needed for drug to dissolve completely, gently swirl solution for 5–10 seconds every 5 minutes until no visible gel-like particles present.1 Small bubbles or foam may remain in vial.1 Resulting solution will be slightly viscous and clear or slightly opalescent.1

Discard solution if foreign particles present or if drug does not dissolve completely within 40 minutes after attempting reconstitution.1

Rate of Administration

May take 5–10 seconds to inject sub-Q.1


Pediatric Patients

Moderate to Severe Allergic Asthma

Adolescents ≥12 years of age: 150–375 mg every 2 or 4 weeks.1 Base dosage and dosing frequency on total serum IgE concentrations, measured prior to therapy, and body weight (see Table 1 and see Table 2).1 10

Chronic Idiopathic Urticaria

Adolescents ≥12 years of age: 150 or 300 mg every 4 weeks.1 Dosage not dependent on serum IgE concentrations (free or total) or body weight.1


Moderate to Severe Allergic Asthma

150–375 mg every 2 or 4 weeks.1 Base dosage and dosing frequency on total serum IgE concentrations, measured prior to therapy, and body weight (see Table 1 and see Table 2).1

See Table 2.

Table 1. Omalizumab Doses (mg) Administered Every 4 Weeks

Body Weight (kg)

Pretreatment Serum IgE (IU/mL)



















See Table 1.

Do not administer.

Table 2. Omalizumab Doses (mg) Administered every 2 Weeks

Body Weight (kg)

Pretreatment Serum IgE (IU/mL)

























Chronic Idiopathic Urticaria

150 or 300 mg every 4 weeks.1 Dosage not dependent on serum IgE concentrations (free or total) or body weight.1

Prescribing Limits

Pediatric Patients

Moderate to Severe Allergic Asthma

Maximum 750 mg every 4 weeks.1

Chronic Idiopathic Urticaria

Maximum 300 mg every 4 weeks.1


Moderate to Severe Allergic Asthma

Maximum 750 mg every 4 weeks.1

Chronic Idiopathic Urticaria

Maximum 300 mg every 4 weeks.1

Special Populations

No special population (i.e., age, race, ethnicity, gender) dosage recommendations at this time.1

Cautions for Xolair


  • Known history of severe hypersensitivity to omalizumab or any ingredient in the formulation.1 8 9



Sensitivity Reactions

Anaphylaxis (e.g., bronchospasm, hypotension, syncope, urticaria, angioedema of throat or tongue) reported in patients after administration.1 8 Other signs and symptoms of anaphylaxis included wheezing or dyspnea, dizziness, throat tightness, cough, cutaneous angioedema, generalized pruritus, rapid or weak heartbeat, anxiety (e.g., feeling of impending doom), hoarseness, dysphagia, flushing or warm feeling.1 8 9 Most cases of anaphylaxis occurred within first 60 minutes after first or second dose, but may occur after >1 year of maintenance therapy.1 8 10

Other Warnings/Precautions

Cardiovascular and Cerebrovascular Effects

Slightly higher rate of adverse cardiovascular and cerebrovascular effects (transient ischemic attacks [TIAs], MI, sudden and unexpected chest pain, pulmonary hypertension, pulmonary or venous thromboembolism, unstable angina) observed in patients receiving omalizumab in a 5-year study.1 13 Degree of increased risk of cardiovascular and cerebrovascular events difficult to quantify based on these results.1 13

Advise patients with asthma to not discontinue omalizumab before consulting their clinician.12 13

Be aware of the potential increased risk of cardiovascular and cerebrovascular events.12 Report all such adverse events to FDA MedWatch Program by phone (800-FDA-1088), fax (800-FDA-0178), through the Internet ([Web]), or by mail (MedWatch, HF-2, FDA, 5600 Fishers Lane, Rockville, MD 20852-9787).8 12 13


Breast, melanoma, non-melanoma skin, prostate, parotid gland neoplasms, and other types of neoplasms observed with <1 year of therapy.1 Risk of malignancy with longer exposure to omalizumab or use in patients at higher risk for malignancy (e.g., geriatric individuals, current smokers) not known.1 4

FDA's review of data from a 5-year study of omalizumab revealed no difference in cancer rates of patients receiving omalizumab compared with placebo, but a potential increased risk of malignancy cannot be ruled out.1 13 Report all such adverse events to FDA MedWatch Program.13

Medical Personnel and Facilities

Should be administered by a clinician familiar with management of potentially life-threatening anaphylaxis in a setting where parenteral drugs, oxygen, and equipment are immediately available.1 8 10 Anaphylaxis can occur after any dose of omalizumab, even if prior doses were well tolerated;1 8 9 onset of anaphylaxis may be delayed (e.g., up to 4 days) after administration.1 8 9 Monitor patients following administration (e.g., 2 hours following administration of at least the first 3 doses); optimal observation period not established.1 4 8 10 If a severe hypersensitivity reaction occurs, discontinue drug.1 4 8 9 (See Sensitivity Reactions under Cautions.)

Acute or Worsening Asthma

Not effective in alleviating acute asthma exacerbations; do not use for treatment of acute bronchospasm or status asthmaticus.1

Eosinophilia and Churg-Strauss Syndrome

Systemic eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications, and/or neuropathy sometimes presenting with clinical features of vasculitis consistent with Churg-Strauss syndrome, reported rarely; in almost all cases, these events were associated with reduction of oral corticosteroid therapy.1 Be alert to the development of such manifestations; causal relationship not established.1

Fever, Arthralgia, and Rash

Postmarketing reports of a constellation of signs and symptoms (e.g., arthritis/arthralgia, rash, fever, lymphadenopathy) similar to serum sickness.1

Onset of symptoms reported to occur 1–5 days after first or subsequent injections of omalizumab, with recurrence following additional doses in some patients.1

If patient develops such signs and symptoms, discontinue omalizumab.1

Parasitic (Geohelminthic) Infections

Increased incidence and risk of helminthic infection.1 Monitor patients who are at high risk for geohelminthic infections during therapy.1 6 Insufficient data available to determine the duration of monitoring for such infections after treatment discontinuance.1

Laboratory Test Interferences

Serum total IgE concentrations increase following administration resulting from formation of omalizumab-IgE complexes.1 Such elevations may persist for up to 1 year following drug discontinuance.1

Do not use serum total IgE concentrations obtained <1 year following discontinuance of drug to reassess dosing regimen for patients with asthma; these concentrations may not reflect steady-state free IgE concentrations.1 (See Dosage under Dosage and Administration.)


In clinical studies in patients with asthma, antibodies to omalizumab detected in <0.1% of patients receiving the drug.1

Although data were incomplete, no antibodies to omalizumab reported in patients receiving the drug in clinical trials for treatment of chronic idiopathic urticaria.1

Specific Populations


Category B. Pregnancy registry at 866-496-5247.1


Distributed into milk in cynomolgus monkeys.1 Since IgG distributes into milk in humans, it is expected that omalizumab (IgG1κ monoclonal antibody) will be present in human milk.1 Use with caution.1

Pediatric Use

Use in children <12 years of age not recommended.1

Assessment of risks and benefits does not support use in pediatric patients with allergic asthma 6 to <12 years of age.1

Safety and efficacy not evaluated to date in patients <6 years of age with allergic asthma or in those <12 years of age with chronic idiopathic urticaria.1

Geriatric Use

Insufficient experience in patients ≥65 years of age to determine whether they respond differently from younger adults.1

Common Adverse Effects

Patients with asthma: Arthralgia, general pain, leg pain, fatigue, dizziness, fracture, arm pain, pruritus, dermatitis, earache.1

Patients with chronic idiopathic urticaria: Headache,1 14 16 nasopharyngitis,1 sinusitis,1 16 arthralgia,1 14 nausea,1 cough,1 upper respiratory tract infection (sometimes viral).1 16

Interactions for Xolair

No formal drug interaction studies to date.1

Xolair Pharmacokinetics



Absorbed slowly; peak serum concentrations attained after an average of 7–8 days.1 Absolute bioavailability averages 62%.1


Serum free IgE concentrations reduced ≤1 hour following administration in patients with asthma.1

Maximum suppression of serum free IgE concentrations observed 3 days after first dose in patients with chronic idiopathic urticaria.1


Total IgE does not return to pretreatment concentrations for ≤1 year after drug discontinuance in patients with asthma.1

Free and total IgE concentrations returned toward pretreatment values (i.e., free IgE concentrations increased, total IgE concentrations decreased) over 16-week follow-up period following discontinuance of omalizumab in patients with chronic idiopathic urticaria.1



In animals, no specific uptake of radiolabeled drug by any organ or tissue.1



Degradation of omalizumab (IgG1κ monoclonal antibody) by the reticuloendothelial system and endothelial cells in the liver, and clearance of omalizumab-IgE complexes by the reticuloendothelial system.1

Elimination Route

Eliminated in part into the bile as unchanged drug.1


26 days in asthmatic patients.1

24 days in patients with chronic idiopathic urticaria.1




Powder for Sub-Q Injection

Ship at ≤30°C.1 Store at 2–8°C.1 10 When reconstituted with sterile water for injection, solutions prepared in single-use vials are stable for ≤8 hours at 2–8°C or ≤4 hours at room temperature.1 Protect reconstituted vials from sunlight.1


  • Binds specifically to circulating IgE and blocks its binding with the high-affinity IgE receptor (FcεRI) on the surface of mast cells and basophils.1 2 10 Inhibition of such binding interferes with the synthesis and release of mediators of the allergic response (e.g., leukotrienes, cytokines, chemokines).1 2 5 10

  • Reduces the number of FcεRI on basophils and submucosal cells in atopic patients.1 10

  • Reduces mean serum concentrations of free (unbound) IgE in patients with allergic asthma at recommended dosages.1 2

  • Attenuates the early- and late-phase inflammatory response and the influx of eosinophils into the airways following allergen challenge.2 5 10

  • Mechanism of action for chronic idiopathic urticaria not fully understood;1 15 16 may involve down-regulation of FcεRIs on surface of mast cells and basophils as a result of drug binding to IgE and decreasing circulating IgE.1 14

Advice to Patients

  • Importance of providing a copy of the manufacturer’s medication guide for omalizumab to the patient each time the drug is dispensed.1 8 9

  • Risk of potentially life-threatening anaphylaxis after any dose of omalizumab.1 8 9 Importance of informing patients of signs and symptoms of anaphylaxis.8 9 (See Sensitivity Reactions under Cautions.)

  • Importance of receiving omalizumab in a health-care setting (e.g., clinician’s office) where monitoring for possible anaphylaxis can be performed.1 8 9 10 (See Medical Personnel and Facilities under Cautions.)

  • Importance of informing patients of potential for delayed anaphylaxis (e.g., up to 4 days after administration).1 8

  • Importance of seeking emergency medical attention if signs or symptoms of anaphylaxis occur after leaving the clinician’s office.1 8 9

  • Importance of patient understanding how to obtain emergency medical treatment and further medical care for anaphylaxis.8

  • Importance of adherence to dosing schedules of concomitant therapy for asthma or chronic idiopathic urticaria, including not altering the dose or frequency of such drugs unless otherwise instructed by a clinician.1 8 9

  • Importance of informing patients of possible delay in the effectiveness of omalizumab upon treatment initiation.1 8

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses.1

  • Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.1

  • Importance of informing patients of other important precautionary information.1 (See Cautions.)


Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.



Dosage Forms


Brand Names



For subcutaneous use

202.5 mg (delivers 150 mg/1.2 mL)



AHFS DI Essentials™. © Copyright 2019, Selected Revisions March 1, 2016. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

† Use is not currently included in the labeling approved by the US Food and Drug Administration.


1. Genentech. Xolair (omalizumab) for subcutaneous use prescribing information. South San Francisco, CA; 2014 Sep.

2. Johansson SG, Haahtela T, and O’Byrne PM. Omalizumab and the immune system: an overview of preclinical and clinical data. Ann Allergy Asthma Immunol. 2002; 89:132-8.

3. Genentech Inc. Manufacturing of Xolair (omalizumab) for subcutaneous use. Available from website. Accessed 2003 June 30.

4. Genentech, San Francisco, CA: Personal communication.

5. National Institutes of Health, National Heart, Lung, and Blood Institute. Global initiative for asthma: global strategy for asthma management and prevention. Bethesda, MD: National Institutes of Health. 2009 Dec. Available from website. Accessed 2010 Sep 23.

6. Chitkara RK, Sarinas PS, Fick RB. Immunoglobulin-E and anti-IgE treatment in lung disease. Monaldi Arch Chest Dis. 2001; 56:514-20.

8. Center for Drug Evaluation and Research, Food and Drug Administration. FDA Information for healthcare professionals: Omalizumab (marketed as Xolair) for subcutaneous use. 2007 Jul. Available at FDA website from website. Accessed 2007 Sep 28.

9. Genentech. Xolair (omalizumab) medication guide. South San Francisco, CA; 2008 Jul.

10. National Asthma Education and Prevention Program. Expert panel report III: guidelines for the diagnosis and management of asthma. 2007 Jul. Bethesda, MD: U.S. Department of Health and Human Services; National Institutes of Health; National Heart, Lung, and Blood Institute. Available from website. Accessed Jul 27, 2008.

11. British Thoracic Society/Scottish Intercollegiate Guidelines Network. Guidelines on the management of asthma: a national clinical guideline. London, Eng; British Thoracic Society. 2008 May. Available from website. Accessed Dec 5, 2008.

12. Food and Drug Administration. Early communication about an ongoing safety review of omalizumab (marketed as Xolair). 2009 Jul 16. Available from FDA website.

13. Food and Drug Administration. FDA drug safety communication: FDA approves label changes for asthma drug Xolair (omalizumab), including describing slightly higher risk of heart and brain adverse events. 2014 Sep 26. From the FDA website. Accessed 2015 Oct 23.

14. Saini SS, Bindslev-Jensen C, Maurer M et al. Efficacy and safety of omalizumab in patients with chronic idiopathic/spontaneous urticaria who remain symptomatic on H1 antihistamines: a randomized, placebo-controlled study. J Invest Dermatol. 2015; 135:67-75.

15. Maurer M, Rosén K, Hsieh HJ et al. Omalizumab for the treatment of chronic idiopathic or spontaneous urticaria. N Engl J Med. 2013; 368:924-35.

16. Kaplan A, Ledford D, Ashby M et al. Omalizumab in patients with symptomatic chronic idiopathic/spontaneous urticaria despite standard combination therapy. J Allergy Clin Immunol. 2013; 132:101-9.

17. Maurer M, Magerl M, Metz M et al. Revisions to the international guidelines on the diagnosis and therapy of chronic urticaria. J Dtsch Dermatol Ges. 2013; 11:971-7; quiz 978.