General Information

Xolair is a recombinant DNA-derived humanized IgG1k monoclonal antibody that selectively binds to human immunoglobulin E (IgE). This limits the degree of release of mediators of the allergic response.

Xolair is specifically indicated for the following:

• adults and children (6 years of age and above) with moderate to severe persistent asthma who have a positive skin test or in vitro reactivity to a perennial aeroallergen and whose symptoms are inadequately controlled with inhaled corticosteroids;
• chronic idiopathic urticaria in adults and adolescents 12 years of age and older who remain symptomatic despite H1 antihistamine treatment;
• nasal polyps in adult patients 18 years of age and older with inadequate response to nasal corticosteroids, as add-on maintenance treatment

Xolair is supplied as a powder for reconstitution into a solution for subcutaneous injection. The recommended dosing is as follows:

• 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 Idiopathic Urticaria: Xolair 150 or 300 mg SC every 4 weeks. Dosing is not dependent on serum IgE level or body weight. 
• 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)

Xolair is also supplied as a prefilled syringe for self-injection for all indications. Before starting self-injection with Xolair prefilled syringe, the patient must have no prior history of anaphylaxis and be closely observed by a healthcare provider for at least three injections with no hypersensitivity. 

Clinical Results

FDA Approval
The FDA approval of Xolair for asthma was based on three randomized, double-blind, placebo-controlled, multicenter trials. The trials enrolled patients 12 to 76 years old, with moderate to severe persistent asthma for at least one year, and a positive skin test reaction to a perennial aeroallergen.

Studies One and Two
At screening, patients in Studies 1 and 2 had a forced expiratory volume in one second (FEV1) between 40% and 80% predicted. All subjects were being treated with inhaled corticosteroids (ICS) and short acting beta-agonists. The studies were comprised of a run-in period to achieve a stable conversion to a common ICS (beclomethasone dipropionate) followed by randomization to Xolair or placebo. Xolair was administered for 16 weeks with an unchanged corticosteroid dose unless an acute exacerbation necessitated an increase (referred to as the stable steroid phase). The subjects then entered an ICS reduction phase of 12 weeks during which ICS dose reduction was attempted in a step-wise manner (referred to as the Steroid Reduction Phase). The subjects were treated according to a dosing table to administer at least 0.016 mg/kg/IU (IgE/mL) of Xolair or a matching volume of placebo over each 4-week period. The maximum Xolair dose per 4 weeks was 750 mg. Those who were to receive more than 300 mg within the 4-week period were administered half the total dose every 2 weeks. In both Studies 1 and 2 the number of exacerbations per patient was reduced in patients treated with Xolair compared with placebo. Stable Steroid Phase Study One: Mean number exacerbations/patient was 0.2% for Xolair and and 0.3% for placebo (p- 0.005). Study Two: Mean number exacerbations/patient was 0.1% for Xolair and 0.4% for placebo (p< 0.001). Steroid Reduction Phase Study One: Mean number exacerbations/patient was 0.2% for Xolair and 0.4% for placebo (p- 0.004). Study Two: Mean number exacerbations/patient was 0.2% and 0.3% (p< 0.001). Improvements in measures of airflow (FEV1) and asthma symptoms were also observed.

Study Three
In Study 3 there was no restriction on screening FEV1. Long-acting beta-agonists were allowed and subjects were receiving at least 1000 µg/day fluticasone propionate; a subset was also receiving oral corticosteroids. The studies were comprised of a run-in period to achieve a stable conversion to a common ICS (fluticasone propionate) followed by randomization to Xolair or placebo. Subjects were stratified by use of ICS-only or ICS with concomitant use of oral steroids. Xolair was administered for 16 weeks with an unchanged corticosteroid dose unless an acute exacerbation necessitated an increase (referred to as the stable steroid phase). The subjects then entered an ICS reduction phase of 16 weeks during which ICS (or oral steroid in Study 3 subset) dose reduction was attempted in a step-wise manner (referred to as the Steroid Reduction Phase). The subjects were treated according to a dosing table to administer at least 0.016 mg/kg/IU (IgE/mL) of Xolair or a matching volume of placebo over each 4-week period. The maximum Xolair dose per 4 weeks was 750 mg. Those who were to receive more than 300 mg within the 4-week period were administered half the total dose every 2 weeks. In Study 3 the number of exacerbations in patients treated with Xolair was similar to that in placebo-treated patients. The absence of an observed treatment effect was postulated to be related to differences in the patient population. Stable Steroid Phase Inhaled Only: % Patients with ≥ 1 exacerbations was 15.9% for Xolair and 15.0% for placebo. Oral plus Inhaled: % Patients with ≥ 1 exacerbations was 32.0% for Xolair and 22.2% for placebo. Steroid Reduction Phase Inhaled Only: % Patients with ≥ 1 exacerbations was 22.2% for Xolair and 26.7% for placebo. Oral plus Inhaled: % Patients with ≥ 1 exacerbations was 42.0% for Xolair and 42.2% for placebo. ). Improvements in measures of airflow (FEV1) and asthma symptoms were also observed.

The FDA approval of Xolair for chronic idiopathic urticaria in patients 12 years and older who remained symptomatic despite taking H1-antihistamines was assessed using a scale known as the average (mean) weekly Itch Severity Score (ISS) at Week 12. The weekly ISS has potential scores ranging from 0 to 215. In ASTERIA I, Xolair 150 mg improved ISS from the starting measurement by 47 percent (-6.7) and Xolair 300 mg improved ISS from the starting measurement by 66 percent (-9.4) at Week 12, compared to a 25 percent (-3.6) score improvement for patients who received placebo. Also, a larger proportion of patients (36 percent) treated with Xolair 300 mg reported no itch and no hives at Week 12, compared to patients treated with Xolair 150 mg (15 percent), and patients in the placebo group (9 percent) . Similar results were observed for the ASTERIA II study.

The FDA approval of Xolair for nasal polyps was based on results from the Phase III POLYP 1 and POLYP 2 trials. Both trials showed that adult patients with nasal polyps who had an inadequate response to nasal corticosteroids and received Xolair had statistically significant greater improvement from baseline at Week 24 in Nasal Polyp Score (NPS) and weekly average Nasal Congestion Score (NCS) than patients who received placebo. In POLYP 1 and POLYP 2, the mean change from baseline at Week 24 for Xolair compared to placebo were: NPS, -1.1 vs 0.1 and -0.9 vs -0.3, respectively; NCS, -0.9 vs -0.4 and -0.7 vs -0.2, respectively.

Side Effects

Adverse events associated with the use of Xolair may include, but are not limited to, the following:

• Injection site reaction
• Viral infections
• Upper respiratory tract infection
• Sinusitis
• Headache
• Pharyngitis

Mechanism of Action

Xolair inhibits the binding of IgE to the high-affinity IgE receptor (Fc&RI) on the surface of mast cells and basophils. Reduction in surface-bound IgE on Fc&RI-bearing cells limits the degree of release of mediators of the allergic response. Treatment with Xolair also reduces the number of Fc&RI receptors on basophils in atopic patients.

Additional Information

For additional information regarding Xolair or asthma, please visit the Xolair web page.