Xolair

Indications : Asthma

Pregnancy Category B

FDA Approved 2003 Jun

DRUG CLASS : : Monoclonal antibodies

BRAND NAMES : Xolair (US);

DESCRIPTION :

For Subcutaneous Use

Xolair is a recombinant DNA-derived humanized IgG1? monoclonal antibody that selectively binds to human immunoglobulin E (IgE). The antibody has a molecular weight of approximately 149 kilodaltons. Xolair is produced by a Chinese hamster ovary cell suspension culture in a nutrient medium containing the antibiotic gentamicin. Gentamicin is not detectable in the final product.

Xolair is a sterile, white, preservative-free, lyophilized powder contained in a single-use vial that is reconstituted with sterile water for injection (SWFI), and administered as a subcutaneous (SC) injection. A Xolair vial contains 202.5 mg of omalizumab, 145.5 mg sucrose, 2.8 mg L-histidine hydrochloride monohydrate, 1.8 mg L-histidine, and 0.5 mg polysorbate 20, and is designed to deliver 150 mg of omalizumab in 1.2 ml after reconstitution with 1.4 ml SWFI.

CLINICAL PHARMACOLOGY :

Mechanism of Action

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

Pharmacokinetics

After SC administration, omalizumab is absorbed with an average absolute bioavailability of 62%. Following a single SC dose in adult and adolescent patients with asthma, omalizumab was absorbed slowly, reaching peak serum concentrations after an average of 7-8 days. The pharmacokinetics of omalizumab are linear at doses greater than 0.5 mg/kg. Following multiple doses of omalizumab, areas under the serum concentration-time curve from Day 0 to Day 14 at steady-state were up to 6-fold of those after the first dose.

In vitro, omalizumab forms complexes of limited size with IgE. Precipitating complexes and complexes larger than 1 million daltons in molecular weight are not observed in vitro or in vivo . Tissue distribution studies in cynomolgus monkeys showed no specific uptake of 125I-omalizumab by any organ or tissue. The apparent volume of distribution in patients following SC administration was 78 ± 32 ml/kg.

Clearance of omalizumab involves IgG clearance processes as well as clearance via specific binding and complex formation with its target ligand, IgE. Liver elimination of IgG includes degradation in the liver reticuloendothelial system (RES) and endothelial cells. Intact IgG is also excreted in bile. In studies with mice and monkeys, omalizumab:IgE complexes were eliminated by interactions with Fc? receptors within the RES at rates that were generally faster than IgG clearance. In asthma patients omalizumab serum elimination half-life averaged 26 days, with apparent clearance averaging 2.4 ± 1.1 ml/kg/day. In addition, doubling body weight approximately doubled apparent clearance.

Pharmacodynamics

In clinical studies, serum free IgE levels were reduced in a dose dependent manner within 1 hour following the first dose and maintained between doses. Mean serum free IgE decrease was greater than 96% using recommended doses. Serum total IgE levels (i.e., bound and unbound) increased after the first dose due to the formation of omalizumab:IgE complexes, which have a slower elimination rate compared with free IgE. At 16 weeks after the first dose, average serum total IgE levels were 5-fold higher compared with pre-treatment when using standard assays. After discontinuation of omalizumab dosing, the omalizumab-induced increase in total IgE and decrease in free IgE were reversible, with no observed rebound in IgE levels after drug washout. Total IgE levels did not return to pre-treatment levels for up to 1 year after discontinuation of omalizumab.

Special Populations

The population pharmacokinetics of omalizumab were analyzed to evaluate the effects of demographic characteristics. Analyses of these limited data suggest that no dose adjustments are necessary for age (12-76 years), race, ethnicity, or gender.

CLINICAL STUDIES :

The safety and efficacy of omalizumab were evaluated in three randomized, double-blind, placebo-controlled, multicenter trials.

The trials enrolled patients 12-76 years old, with moderate to severe persistent (NHLBI criteria) asthma for at least 1 year, and a positive skin test reaction to a perennial aeroallergen. At screening, patients in Studies 1 and 2 had a forced expiratory volume in 1 second (FEV1) between 40 and 80% predicted, while in Study 3 there was no restriction on screening FEV1. All patients had a FEV1 improvement of at least 12% following beta-agonist administration. All patients were symptomatic and were being treated with inhaled corticosteroids (ICS) and short acting beta-agonists. In Study 3, long-acting beta-agonists were allowed. Study 3 patients were receiving at least 1000 µg/day fluticasone propionate and a subset was also receiving oral corticosteroids. Patients receiving other concomitant controller medications were excluded, and initiation of additional controller medications while on study was prohibited. Patients currently smoking were excluded.

Each study was comprised of a run-in period to achieve a stable conversion to a common ICS (beclomethasone dipropionate, for Studies 1 and 2; fluticasone propionate for Study 3), followed by randomization to omalizumab or placebo. In Study 3, patients were stratified by use of ICS-only or ICS with concomitant use of oral steroids. Patients received omalizumab for 16 weeks with an unchanged corticosteroid dose unless an acute exacerbation necessitated an increase. Patients then entered an ICS reduction phase of 12 weeks (Studies 1 and 2) or 16 weeks (Study 3) during which ICS (or oral steroid in Study 3 subset) dose reduction was attempted in a step-wise manner.

Omalizumab dosing was based on body weight and baseline serum total IgE concentration. All patients were required to have a baseline IgE between 30 and 700 IU/ml and body weight not more than 150 kg. Patients were treated according to a dosing table to administer at least 0.016 mg/kg/IU (IgE/ml) of omalizumab or a matching volume of placebo over each 4 week period. The maximum omalizumab dose per 4 weeks was 750 mg; patients who had a weight-IgE combination that yielded a dose greater than 750 mg were excluded from the studies. Patients who were to receive more than 300 mg within the 4 week period were administered half the total dose every 2 weeks.

The distribution of the number of asthma exacerbations per patient in each group during a study was analyzed separately for the stable steroid and steroid-reduction periods. In all three studies an exacerbation was defined as a worsening of asthma that required treatment with systemic corticosteroids or a doubling of the baseline ICS dose.

In both Studies 1 and 2 the number of exacerbations per patient was reduced in patients treated with omalizumab compared with placebo (TABLE 1). In Study 3 the number of exacerbations in patients treated with omalizumab was similar to that in placebo-treated patients (TABLE 2). The absence of an observed treatment effect in Study 3 may be related to differences in the patient population compared with Studies 1 and 2, study sample size, or other factors. In all three studies most exacerbations were managed in the out-patient setting and the majority were treated with systemic steroids. Hospitalization rates were not significantly different between omalizumab and placebo-treated patients; however, the overall hospitalization rate was small. Among those patients who experienced an exacerbation, the distribution of exacerbation severity was similar between treatment groups.

TABLE 1 Frequency of Asthma Exacerbations per Patient by Phase in Studies 1 and 2
Study 1
Study 2
Omalizumab
Placebo
Omalizumab
Placebo
Exacerbations per Patient
n=268
n=257
n=274
n=272
Stable Steroid Phase (16 Weeks)
0
85.8%
76.7%
87.6%
69.9%
1
11.9%
16.7%
11.3%
25.0%
=2
2.2%
6.6%
1.1%
5.1%
p-Value
0.005
<0.001
Mean number exacerbations/patients
0.2%
0.3%
0.1%
0.4%
Steroid Reduction Phase (12 Weeks)
0
78.7%
67.7%
83.9%
70.2%
1
19.0%
28.4%
14.2%
26.1%
=2
2.2%
3.9%
1.8%
3.7%
p-Value
0.004
>0.001
Mean number exacerbations/patient
0.2%
0.4%
0.2%
0.3%
TABLE 2 Percentage of Patients with Asthma Exacerbations by Subgroup and Phase in Study 3
Inhaled Only
Oral + Inhaled
Omalizumab
Placebo
Omalizumab
Placebo
n=126
n=120
n=50
n=45
Stable Steroid Phase (16 Weeks)
Patients with =1 exacerbations
15.9%
15.0%
32.0%
22.2%
Difference (95% CI)
0.9 (-9.7, 13.7)
9.8 (-10.5, 31.4)
Steroid Reduction Phase (12 Weeks)
Patients with =1 exacerbations
22.2%
26.7%
42.0%
42.2%
Difference (95% CI)
-4.4 (-17.6, 7.4)
-0.2 (-22.4, 20.1)

In all three of the studies, a reduction of asthma exacerbations was not observed in the omalizumab-treated patients who had FEV1 > 80% at the time of randomization. Reductions in exacerbations were not seen in patients who required oral steroids as maintenance therapy.

In Studies 1 and 2 measures of airflow (FEV1) and asthma symptoms were evaluated (TABLE 3). The clinical relevance of the treatment-associated differences is unknown.

TABLE 3 Asthma Symptoms and Pulmonary Function During Stable Steroid Phase of Study 1
Omalizumab
Placebo
n=268*
n=257*
Endpoint
Mean Baseline
Median Change (Baseline to Week 16)
Mean Baseline
Median Change (Baseline to Week 16)
Ttoal asthma symptom score
4.3
-1.5†
4.2
-1.1†
Nocturnal asthma score
1.2
-0.4†
1.1
-0.2†
Daytime asthma score
2.3
-0.9†
2.3
-0.6†
FEV1% predicted
68
3†
68
0†
Asthma symptom scale: total score from 0 (least) to 9 (most); nocturnal and daytime scores from 0 (least) to 4 (most symptoms).
* Number of patients available for analysis ranges 255-258 in the omalizumab group and 238-239 in the placebo group.
Comparison of omalizumab versus placebo (p <0.05).

Results from the stable steroid phase of Study 2 and the steroid reduction phases of both Studies 1 and 2 were similar to those presented in TABLE 3.

INDICATIONS AND USAGE :

Omalizumab is indicated for adults and adolescents (12 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. Omalizumab has been shown to decrease the incidence of asthma exacerbations in these patients. Safety and efficacy have not been established in other allergic conditions.

CONTRAINDICATIONS :

Omalizumab should not be administered to patients who have experienced a severe hypersensitivity reaction to omalizumab (see WARNINGS, Anaphylaxis).

WARNINGS :

Malignancy

Malignant neoplasms were observed in 20 of 4127 (0.5%) omalizumab-treated patients compared with 5 of 2236 (0.2%) control patients in clinical studies of asthma and other allergic disorders. The observed malignancies in omalizumab-treated patients were a variety of types, with breast, non-melanoma skin, prostate, melanoma, and parotid occurring more than once, and five other types occurring once each. The majority of patients were observed for less than 1 year. The impact of longer exposure to omalizumab or use in patients at higher risk for malignancy (e.g., elderly, current smokers) is not known (see ADVERSE REACTIONS).

Anaphylaxis

Anaphylaxis has occurred within 2 hours of the first or subsequent administration of omalizumab in 3 (<0.1%) patients without other identifiable allergic triggers. These events included urticaria and throat and/or tongue edema (see ADVERSE REACTIONS). Patients should be observed after injection of omalizumab, and medications for the treatment of severe hypersensitivity reactions including anaphylaxis should be available. If a severe hypersensitivity reaction to omalizumab occurs, therapy should be discontinued (see CONTRAINDICATIONS).

PRECAUTIONS :

General

Omalizumab has not been shown to alleviate asthma exacerbations acutely and should not be used for the treatment of acute bronchospasm or status asthmaticus.

Corticosteroid Reduction

Systemic or inhaled corticosteroids should not be abruptly discontinued upon initiation of omalizumab therapy. Decreases in corticosteroids should be performed under the direct supervision of a physician and may need to be performed gradually.

Information for the Patient

Patients receiving omalizumab should be told not to decrease the dose of, or stop taking any other asthma medications unless otherwise instructed by their physician. Patients should be told that they may not see immediate improvement in their asthma after beginning omalizumab therapy.

Laboratory Tests

Serum total IgE levels increase following administration of omalizumab due to formation of omalizumab:IgE complexes (see CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION). Elevated serum total IgE levels may persist for up to 1 year following discontinuation of omalizumab. Serum total IgE levels obtained less than 1 year following discontinuation may not reflect steady-state free IgE levels and should not be used to reassess the dosing regimen.

Carcinogenesis, Mutagenesis, and Impairment of Fertility

No long-term studies have been performed in animals to evaluate the carcinogenic potential of omalizumab.

No evidence of mutagenic activity was observed in Ames tests using six different strains of bacteria with and without metabolic activation at omalizumab concentrations up to 5000 µg/ml.

The effects of omalizumab on male and female fertility have been assessed in cynomolgus monkey studies. Administration of omalizumab at doses up to and including 75 mg/kg/week did not elicit reproductive toxicity in male cynomolgus monkeys and did not inhibit reproductive capability, including implantation, in female cynomolgus monkeys. These doses provide a 2- to 16-fold safety factor based on total dose and 2- to 5-fold safety factor based on AUC over the range of adult clinical doses.

Pregnancy Category B

Reproduction studies in cynomolgus monkeys have been conducted with omalizumab. Subcutaneous doses up to 75 mg/kg (12-fold the maximum clinical dose) of omalizumab did not elicit maternal toxicity, embryotoxicity, or teratogenicity when administered throughout organogenesis and did not elicit adverse effects on fetal or neonatal growth when administered throughout late gestation, delivery, and nursing.

IgG molecules are known to cross the placental barrier. There are no adequate and well-controlled studies of omalizumab in pregnant women. Because animal reproduction studies are not always predictive of human response, omalizumab should be used during pregnancy only if clearly needed.

Nursing Mothers

The excretion of omalizumab in milk was evaluated in female cynomolgus monkeys receiving SC doses of 75 mg/kg/week. Neonatal plasma levels of omalizumab after in utero exposure and 28 days of nursing were between 11% and 94% of the maternal plasma level. Milk levels of omalizumab were 1.5% of maternal blood concentration. While omalizumab presence in human milk has not been studied, IgG is excreted in human milk and therefore it is expected that omalizumab will be present in human milk. The potential for omalizumab absorption or harm to the infant are unknown; caution should be exercised when administering omalizumab to a nursing woman.

Pediatric Use

Safety and effectiveness in pediatric patients below the age of 12 have not been established.

Geriatric Use

In clinical trials 134 patients 65 years of age or older were treated with omalizumab. Although there were no apparent age-related differences observed in these studies, the number of patients aged 65 and over is not sufficient to determine whether they respond differently from younger patients.

DRUG INTERACTIONS :

No formal drug interaction studies have been performed with omalizumab. The concomitant use of omalizumab and allergen immunotherapy has not been evaluated.

ADVERSE REACTIONS :

The most serious adverse reactions occurring in clinical studies with omalizumab are malignancies and anaphylaxis (see WARNINGS). The observed incidence of malignancy among omalizumab-treated patients (0.5%) was numerically higher than among patients in control groups (0.2%). Anaphylactic reactions were rare but temporally associated with omalizumab administration.

The adverse reactions most commonly observed among patients treated with omalizumab included injection site reaction (45%), viral infections (23%), upper respiratory tract infection (20%), sinusitis (16%), headache (15%), and pharyngitis (11%). These events were observed at similar rates in omalizumab-treated patients and control patients. These were also the most frequently reported adverse reactions resulting in clinical intervention (e.g., discontinuation of omalizumab, or the need for concomitant medication to treat an adverse reaction).

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of one drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in medical practice.

The data described above reflect omalizumab exposure for 2076 adult and adolescent patients ages 12 and older, including 1687 patients exposed for 6 months and 555 exposed for 1 year or more, in either placebo-controlled or other controlled asthma studies. The mean age of patients receiving omalizumab was 42 years, with 134 patients 65 years of age or older; 60% were women, and 85% Caucasian. Patients received omalizumab 150-375 mg every 2 or 4 weeks or, for patients assigned to control groups, standard therapy with or without a placebo.

TABLE 4 shows adverse events that occurred =1% more frequently in patients receiving omalizumab than in those receiving placebo in the placebo-controlled asthma studies. Adverse events were classified using preferred terms from the International Medical Nomenclature (IMN) dictionary. Injection site reactions were recorded separately from the reporting of other adverse events and are described following TABLE 4.

TABLE 4 Adverse Events =1% More Frequent in Omalizumab-Treated Patients
Omalizumab
Placebo
Adverse Event
n=738
n=717
Body as a Whole
Pain
7%
5%
Fatigue
3%
2%
Musculoskeletal System
Arthralgia
8%
6%
Fracture
2%
1%
Leg pain
4%
2%
Arm pain
2%
1%
Nervous System
Dizziness
3%
2%
Skin and Appendages
Pruritus
2%
1%
Dermaititis
2%
1%
Special Senses
Earache
2%
1%

Age (among patients under age 65), race, and gender did not appear to affect the between group differences in the rates of adverse events.

Injection Site Reactions

Injection site reactions of any severity occurred at a rate of 45% in omalizumab-treated patients compared with 43% in placebo-treated patients. The types of injection site reactions included: bruising, redness, warmth, burning, stinging, itching, hive formation, pain, indurations, mass, and inflammation.

Severe injection-site reactions occurred more frequently in omalizumab-treated patients compared with patients in the placebo group (12% vs 9%).

The majority of injection site reactions occurred within 1 hour-post injection, lasted less than 8 days, and generally decreased in frequency at subsequent dosing visits.

Immunogenicity

Low titers of antibodies to omalizumab were detected in approximately 1/1723 (<0.1%) of patients treated with omalizumab. The data reflect the percentage of patients whose test results were considered positive for antibodies to omalizumab in an ELISA assay and are highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody positivity in the assay may be influenced by several factors including sample handling, timing of sample collection, concomitant medications, and underlying disease. Therefore, comparison of the incidence of antibodies to omalizumab with the incidence of antibodies to other products may be misleading.

Allergic symptoms, including urticaria, dermatitis, and pruritus were observed in patients treated with omalizumab. There were also 3 cases of anaphylaxis observed within 2 hours of omalizumab administration in which there were no other identifiable allergic triggers (see WARNINGS, Anaphylaxis).

OVERDOSAGE :

The maximum tolerated dose of omalizumab has not been determined. Single IV doses of up to 4000 mg have been administered to patients without evidence of dose-limiting toxicities. The highest cumulative dose administered to patients was 44,000 mg over a 20 week period, which was not associated with toxicities.

DOSAGE AND ADMINISTRATION :

Omalizumab 150-375 mg is administered SC every 2 or 4 weeks. Because the solution is slightly viscous, the injection may take 5-10 seconds to administer. Doses (mg) and dosing frequency are determined by serum total IgE level (IU/ml), measured before the start of treatment, and body weight (kg). See the dose determination charts below (TABLE 5 and TABLE 6) for appropriate dose assignment. Doses of more than 150 mg are divided among more than 1 injection site to limit injections to not more than 150 mg per site.

TABLE 5 ADMINISTRATION EVERY 4 WEEKS: Omalizumab Doses (mg) Administered by SC Injection Every 4 Weeks for Adults and Adolescents (12 Years of Age and Older) With Asthma
Body Weight (kg)
Pre-Treatment Serum IgE (IU/ml)
30 to 60
>60 to 70
>70 to 90
>90 to 150
=30-100
150
150
150
300
>100-200
300
300
300
*
>200-300
300
*
*
*
>300-400
*
*
*
*
>400-500
*
*
*
*
>500-600
*
*
*
*
* See TABLE 6.

 

TABLE 6 ADMINISTRATION EVERY 2 WEEKS: Omalizumab Doses (mg) Administered by Subcutaneous Injection Every 2 Weeks for Adults and Adolescents (12 Years of Age and Older) With Asthma
Body Weight (kg)
Pre-Treatement Serum IgE (IU/ml)
30 to 60
>60 to 70
>70 to 90
>90 to 150
=30-100
*
*
*
*
>100-200
*
*
*
225
>200-300
*
225
225
300
>300-400
225
225
300
>400-500
300
300
375
>500-600
300
375
>600-700
375
* See TABLE 5.
DO NOT USE.

Dose Adjustment

Total IgE levels are elevated during treatment and remain elevated for up to 1 year after the discontinuation of treatment. Therefore, re-testing of IgE levels during omalizumab treatment cannot be used as a guide for dose determination. Dose determination after treatment interruptions lasting less than 1 year should be based on serum IgE levels obtained at the initial dose determination. Total serum IgE levels may be re-tested for dose determination if treatment with omalizumab has been interrupted for 1 year or more.

Doses should be adjusted for significant changes in body weight. (See TABLE 5 and TABLE 6.)

Stability and Storage

Omalizumab should be shipped at controlled ambient temperature [=30°C (=86°F)]. Omalizumab should be stored under refrigerated conditions 2-8°C (36-46°F). Do not use beyond the expiration date stamped on carton.

Omalizumab is for single-use only and contains no preservatives. The solution may be used for SC administration within 8 hours following reconstitution when stored in the vial at 2-8°C (36-46°F), or within 4 hours of reconstitution when stored at room temperature.

Reconstituted omalizumab vials should be protected from direct sunlight.

HOW SUPPLIED :

Xolair is supplied as a lyophilized, sterile powder in a single-use, 5 cc vial that is designed to deliver 150 mg of omalizumab upon reconstitution with 1.4 ml SWFI.

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