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Omalizumab: anti-IgE monoclonal antibody E25, E25, humanised anti-IgE MAb, IGE 025, monoclonal antibody E25, Olizumab, Xolair, rhuMAb-E25.

UNLABELLED: Omalizumab [anti-IgE monoclonal antibody E25, E25, humanised anti-IgE MAb, IGE 025, monoclonal antibody E25, olizumab, rhuMAb-E25, Xolair] is a chimeric monoclonal antibody. It binds specifically to the Cepsilon3 domain of immunoglobulin E (IgE). Cepsilon3 is the site of high-affinity IgE receptor binding. IgE plays a major role in allergic disease by causing the release of histamine and other inflammatory mediators from mast cells. Omalizumab binds to and neutralises circulating IgE by preventing IgE from binding to its high-affinity mast-cell receptor. In addition, omalizumab does not bind to or induce histamine release from basophils, nor does it bind to or recognise IgG. The immune complexes formed between IgE and omalizumab in vivo are relatively small (molecular weight <1 million) and are therefore unlikely to cause organ damage. COLLABORATION BETWEEN GENETECH NOVARTIS AND TANOX: omalizumab is very similar to the Tanox product CGP 51901. Genentech (Roche), Novartis and Tanox (formerly Tanox Biosystems) were developing both antibodies in phase II studies, with an agreement to collaborate on phase III development of the most promising one. The Genentech product, omalizumab, was selected for further development. Tanox has marketing rights to the drug in some Asian markets. Novartis and Genentech have marketing rights in the USA. Roche has an option to participate in the commercialisation of omalizumab and other anti-IgE products of the collaboration in Japan and Europe. Roche may exercise this option if specific events relating to commercialisation of the product occur; Roche has waived this option for omalizumab in Japan. If Genentech withdraws from the collaboration, Roche has an option to assume its place. Either Novartis or Genentech may withdraw from the collaboration on short notice, in which case rights to omalizumab revert to Tanox and the remaining collaborator unless Roche exercises its option in the event of withdrawal by Genentech. PATENTS: Protein Design Labs holds fundamental antibody humanisation patents. Protein Design Labs stated in its Annual Report for 2000 that Genentech may elect to take a patent licence for Xolair under a 1998 patent rights agreement. CLINICAL TRIALS: Phase III clinical trials of omalizumab for the treatment of allergic rhinitis and allergic asthma were in progress with Genentech (Roche) in the USA, Canada, Europe and Japan, and are now completed. In New Zealand, the antibody was investigated in clinical trials for the treatment of allergic asthma at the Wellington School of Medicine. In the phase III trials, omalizumab was administered as a subcutaneous injection. It may also be administered intravenously. In additional phase I and II studies, the safety and efficacy of aerosol administration for allergic asthma was tested. Initial results of these studies indicated that aerosol administration is less effective than intravenous or subcutaneous administration. TEMPORARY SUSPENSION OF TRIALS: In September 2000, the US FDA requested that Genentech and Novartis suspend new trials of omalizumab. Existing long-term trials, however, could continue. The hold on new trials was due to concerns about the preclinical toxicity of omalizumab and the follow-up antibody E26. Thrombocytopenia was reported in studies in monkeys for omalizumab at 5-27 times the maximum clinical dose and for E26 at 3-15 times the maximum dose. In response to FDA requests, Novartis and Genentech carried out additional preclinical trials so that a specific explanation of the toxicity could be obtained; Novartis suspected a species specificity for the adverse events, as no thrombocytopenic events occurred in the completed phase III clinical trials. The supplementary data were submitted to the FDA and the hold on clinical trials was lifted in November 2000. REGULATORY FILINGS: in June 2000, Genentech, Novartis and Tanox submitted a Biologics Licence Application (BLA) to the US FDA for approval of omalizumab for the treatment of allergic asthma and allergic rhinitis. Novartis fileiled for marketing approval of omalizumab in the European Union, Switzerland, Australia and New Zealand. INDICATION NARROWED TO ADULT ALLERGIC ASTHMA: In July 2001, the FDA requested additional data, both preclinical and clinical, for Xolair, as well as more detailed information concerning the effect of prolonged action of the drug. Genentech is to satisfy the FDA's request with data from the ALTO platelet monitoring safety study and with ongoing open-label studies. Genentech, Novartis and Tanox believe that substantial information can be provided from continuing trials, but additional trials on specific subgroups may be necessary. The new data will be submitted to both the US FDA and the EMEA in the European Union. The application for approval of Xolair that was submitted to the EMEA was withdrawn when it became clear that there would be a delay in approval in the USA. Tanox had originally anticipated that Xolair would be launched in mid-2001 in the USA and Europe. In November 2001, Genentech and Novartis stated that an amended BLA would be submitted to the FDA in the fourth quarter of 2002. The amended approval application will focus on the use of Xolair in adults only with allergic asthma. The original application was for treatment of both adults and children, and included allergic rhinitis. Genentech has stated that it will first pursue the narrower indication before filing supplemental BLAs. Approval of the drug in the USA may now be delayed until as late as the end of 2003. In Europe, Novartis is planning to develop Xolair for use only in asthmatic patients who are classed as being 'at risk', i.e. those who have been hospitalised or have visited an emergency department. Clinical studies are to be carried out, with submission for regulatory approval planned for 2003. APPROVAL IN AUSTRALIA: In June 2002, Xolair was approved by the Therapeutic Goods Administration in Australia for the treatment of adults and adolescents with moderate allergic asthma. This is the first marketing approval for Xolair.

Antibodies, Anti-Idiotypic↗

Treatment of childhood asthma with anti-immunoglobulin E antibody (omalizumab).

BACKGROUND AND OBJECTIVE: There seems to be a strong causal relationship between allergy and the origins of asthma. Susceptibility to both is determined by a combination of genetics and environment acting through a complex network of cytokines. Nearly 90% of affected children have positive skin tests indicating the presence of specific immunoglobulin E (IgE), with sensitivity to house dust mite, Alternaria, cockroach, cat, and dog most closely linked to the disease. Greater exposure to house dust mite during infancy leads to earlier onset of wheezing, and elevated serum IgE levels correlate with the appearance of asthma symptoms. Specific IgE binds to high-affinity (FcepsilonRI) receptors on mast cells and basophils. The IgE-mediated reactions that follow exposure of sensitized mast cells to an allergen are designated early- and late-phase asthmatic responses (EAR and LAR). EAR is characterized by release of histamine and other preformed mediators within 1 hour of allergen exposure. It is often followed by LAR, an infiltration of the airways by inflammatory cells associated with an episode of more prolonged, and usually more severe airflow obstruction, 4 to 8 hours after antigen exposure. Chronic airway symptoms result from persistent LAR caused by continuous allergen exposure. IgE antibodies are capable of passive transfer of both EAR and LAR sensitivity. IgE-mediated mast cell activation contributes to chronic tissue eosinophilia and airway remodeling, with permanent loss in pulmonary function. Omalizumab (rhuMAb-E25) is a recombinant, humanized, monoclonal anti-IgE antibody of mouse origin developed for the treatment of IgE-mediated diseases. Omalizumab binds to free IgE at the same site as the high-affinity receptor. Although it attaches to free IgE, it does not bind to IgA, IgG, or cell-bound IgE. It therefore does not induce cross-linking of cell-bound IgE, which would lead to the release of allergic mediators. It has been reported to decrease serum IgE levels in a dose-dependent manner, inhibit EAR and LAR, and cause a down-regulation of FcepsilonRI receptors on basophils. Omalizumab has been reported to be safe and effective in improving asthma control and reducing the requirement for oral and inhaled corticosteroids. This double-blind, randomized, placebo-controlled study evaluated the safety, steroid-sparing effects, and impact on disease exacerbations of omalizumab in the treatment of childhood asthma. Methods. Participants were 334 males and premenarchal females aged 6 to 12 years, with moderate to severe allergic asthma requiring treatment with inhaled corticosteroids. During a run-in phase, all children were switched to equivalent doses of beclomethasone dipropionate (BDP), and the dose was adjusted to assure maintenance of asthma control achieved with previous corticosteroid treatment. Children were randomized to subcutaneously administered placebo (N = 109) or omalizumab (N = 225) at a dose based on body weight and initial serum IgE (0.016 mg/kg/IgE [IU/mL] per 4 weeks). BDP dose (initial range 168-420 microg/d) was kept stable for 16 weeks (stable-steroid phase), reduced over 8 weeks to the minimum effective dose (steroid-reduction phase), and maintained constant for the final 4 weeks. RESULTS: More participants in the omalizumab group decreased their BDP dose, and their reduction was greater than that of the placebo group (median reduction 100% vs 66.7%). BDP was withdrawn completely in 55% of the omalizumab group versus 39% of the placebo group. The incidence and the frequency of asthma exacerbations requiring treatment with doubling of BDP dose or systemic corticosteroids were lower in the omalizumab group. The treatment differences were statistically significant during the steroid-reduction phase, during which fewer participants in the omalizumab group had asthma exacerbation episodes (18.2% vs 38.5%), and the mean number of episodes per patient was smaller than with placebo (0.42 vs 2.72). Five asthma exacerbations requiring hospitalization all occurred in the placebo group. Participants' and investigators' global evaluations of treatment effectiveness were more favorable for omalizumab than placebo. Investigators rated effectiveness excellent for 31.5% of the omalizumab group versus 16.3% of the placebo group and good for 44.7% of the omalizumab group versus 32.7% of the placebo group. There was little change in asthma symptom scores or spirometry measurements during either the stable-steroid or steroid dose-reduction phase, with minimal differences between the treatment groups. The requirement for rescue medication in the omalizumab group during both the stable-steroid and steroid dose-reduction phases was consistently lower than at baseline. At week 28, the median number of puffs of rescue medication taken daily was 0 in the omalizumab group and 0.46 in the placebo group. The change from baseline was significant in favor of omalizumab. (ABSTRACT TRUNCATED)

Acute Disease↗

Spotlight on omalizumab in allergic asthma.

Omalizumab (Xolair) is a humanized monoclonal antibody used in the treatment of adolescent and adult patients with moderate to severe allergic asthma inadequately controlled with inhaled corticosteroids (ICS). It selectively binds to circulating immunoglobulin E (IgE) and, thereby, prevents binding of IgE to mast cells and other effector cells. Without surface-bound IgE, these cells are unable to recognize allergens, thus preventing cellular activation by antigens and the subsequent allergic/asthmatic symptoms. Omalizumab decreases free serum IgE levels in a dose-dependent manner, reduces IgE receptor density on effector cells, and significantly improves airway inflammation parameters. Omalizumab is slowly absorbed after subcutaneous administration, and mean elimination half-life is 26 days, thus allowing infrequent administration of the drug. Omalizumab dosage is determined by bodyweight and pretreatment serum total IgE levels. Patients treated with subcutaneous omalizumab in clinical trials received a dosage that was approximately equal to 0.016 mg/kg/IgE (IU/mL) per 4 weeks. Thus, patients received 150 or 300 mg every 4 weeks, or 225, 300, or 375 mg every 2 weeks. In adults and adolescents (> or = 12 years of age) with moderate to severe allergic asthma, subcutaneous administration of omalizumab as add-on therapy with ICS improved the number of asthma exacerbations, rescue medication use, asthma symptom scores, and quality-of-life (QOL) scores compared with placebo during 28- and 32-week double-blind trials. In addition, concomitant ICS use was significantly decreased in patients receiving omalizumab, and in the two largest double-blind trials approximately 40% of omalizumab recipients completely withdrew from ICS therapy while maintaining effective asthma control. In general, results of extension studies showed that the beneficial effects of omalizumab were maintained over a total period of 52 weeks. Omalizumab was well tolerated as add-on therapy with ICS during treatment for up to 52 weeks. Common adverse events in clinical trials included injection site reaction, viral infection, upper respiratory tract infection, sinusitis, headache, and pharyngitis, although the incidence of adverse events with omalizumab was similar to that with placebo. In conclusion, omalizumab, as add-on therapy with ICS, is an effective and well tolerated agent for the treatment of moderate to severe allergic asthma in adolescents and adults. In addition to its symptomatic and QOL benefits, omalizumab therapy allows ICS dosage reduction or discontinuation of ICS in many patients. Comparisons of omalizumab with other asthma therapies have yet to be conducted; however, clinical efficacy and tolerability data indicate that omalizumab is a valuable option in the treatment of allergic asthma.

Adult↗

Omalizumab: a review of its use in the management of allergic asthma.

UNLABELLED: Omalizumab (Xolair) is a humanized monoclonal antibody used in the treatment of adolescent and adult patients with moderate to severe allergic asthma inadequately controlled with inhaled corticosteroids (ICS). It selectively binds to circulating immunoglobulin E (IgE) and, thereby, prevents binding of IgE to mast cells and other effector cells. Without surface-bound IgE, these cells are unable to recognize allergens, thus preventing cellular activation by antigens and the subsequent allergic/asthmatic symptoms. Omalizumab decreases free serum IgE levels in a dose-dependent manner, reduces IgE receptor density on effector cells, and significantly improves airway inflammation parameters. Omalizumab is slowly absorbed after subcutaneous administration, and mean elimination half-life is 26 days, thus allowing infrequent administration of the drug. Omalizumab dosage is determined by bodyweight and pretreatment serum total IgE levels. Patients treated with subcutaneous omalizumab in clinical trials received a dosage that was approximately equal to 0.016 mg/kg/IgE (IU/mL) per 4 weeks. Thus, patients received 150 or 300 mg every 4 weeks, or 225, 300, or 375 mg every 2 weeks. In adults and adolescents (> or =12 years of age) with moderate to severe allergic asthma, subcutaneous administration of omalizumab as add-on therapy with ICS improved the number of asthma exacerbations, rescue medication use, asthma symptom scores, and quality-of-life (QOL) scores compared with placebo during 28- and 32-week double-blind trials. In addition, concomitant ICS use was significantly decreased in patients receiving omalizumab, and in the two largest double-blind trials approximately 40% of omalizumab recipients completely withdrew from ICS therapy while maintaining effective asthma control. In general, results of extension studies showed that the beneficial effects of omalizumab were maintained over a total period of 52 weeks. Omalizumab was well tolerated as add-on therapy with ICS during treatment for up to 52 weeks. Common adverse events in clinical trials included injection site reaction, viral infection, upper respiratory tract infection, sinusitis, headache, and pharyngitis, although the incidence of adverse events with omalizumab was similar to that with placebo. CONCLUSION: Omalizumab, as add-on therapy with ICS, is an effective and well tolerated agent for the treatment of moderate to severe allergic asthma in adolescents and adults. In addition to its symptomatic and QOL benefits, omalizumab therapy allows ICS dosage reduction or discontinuation of ICS in many patients. Comparisons of omalizumab with other asthma therapies have yet to be conducted; however, clinical efficacy and tolerability data indicate that omalizumab is a valuable option in the treatment of allergic asthma.

Antibodies, Anti-Idiotypic↗

Immunological methods for quantifying free and total serum IgE levels in allergy patients receiving omalizumab (Xolair) therapy.

Omalizumab (humanized-IgG1 anti-human IgE Fc, Xolair) complexes circulating IgE, blocking IgE binding to high affinity epsilon Fc receptors (FcepsilonR1) on mast cells and basophils. Free (non-Omalizumab bound) IgE levels in serum are a measure of effective Omalizumab dosing. The goal of this study was to quantify free (non-Omalizumab-complexed) and total serum IgE levels in asthma patients on Xolair. The concentration of (non-Omalizumab bound) free IgE in human serum was measured using a solid phase immunoenzymetric assay (IEMA) in which IgE was captured from serum with monoclonal anti-human IgE (clone HP6061) and detected with labeled-FcepsilonR1alpha. In a companion total human serum IEMA, IgE was captured from serum with the same anti-human IgE (clone HP6061) and all bound IgE was detected with labeled monoclonal anti-human IgE Fc (clone HP6029). Free and total IgE levels were quantified in pre- and 1 and 3 months post Omalizumab therapy sera from 12 allergic asthma patients. In the absence of Omalizumab, working ranges of the free and total IgE IEMAs were comparable (10-1000 kIU/l), with excellent precision, reproducibility and parallelism. Pre-Omalizumab total and free IgE levels by IEMA were highly correlated (r2=0.99, Y=0.9X+0.32, p<0.001), as were total serum IgE levels by IEMA and ImmunoCAP-250 (r2=0.98, Y=1.1X-0.05, p<0.001, n=33). In vitro reduction of free IgE (>90%) occurred at [Omalizumab:IgE] molar ratios of 2-20. Total IgE levels in 12 asthmatics increased from pre-therapy levels (52-658 kIU/l) by 1.5-5.5-fold at 1 month and 1.7-8.6 fold at 3 months of uninterrupted Omalizumab treatment. Free IgE levels fell by 49%-97% at 1 month and 45%-98% by 3 months of Omalizumab treatment. Free and total IgE levels by IEMA aid in monitoring patients receiving Omalizumab therapy.

Adult↗

Exhaled nitric oxide in children with asthma receiving Xolair (omalizumab), a monoclonal anti-immunoglobulin E antibody.

OBJECTIVE: To evaluate the effect of a humanized monoclonal antibody to immunoglobulin E, omalizumab (Xolair, Novartis Pharmaceuticals, East Hanover, NJ; Genentech Inc, South San Francisco, CA), on airway inflammation in asthma, as indicated by the fractional concentration of exhaled nitric oxide (FE(NO)), a noninvasive marker of airway inflammation. Xolair was approved recently by the US Food and Drug Administration for moderate-to-severe allergic asthma in adolescents and adults. STUDY DESIGN: As an addendum at 2 sites to a randomized, multicenter double-blind, placebo-controlled trial, FE(NO) was assessed in children with allergic asthma over 1 year. There were 3 consecutive study periods: 1) stable dosing of inhaled beclomethasone dipropionate (BDP) when the dose was optimized (period of 16 weeks); 2) inhaled steroid-reduction phase (period of 12 weeks), during which BDP was tapered if subjects remained stable; and 3) open-label extension phase, during which subjects receiving placebo were switched to active omalizumab (period of 24 weeks). The primary outcome was area under the FE(NO) versus time curve (AUC) for adjusted FE(NO), defined as the ratio of FE(NO) at each time point compared with the value at baseline. RESULTS: Twenty-nine subjects participated and were randomized to omalizumab (n = 18) and placebo (n = 11) treatment groups in a 2:1 ratio dictated by the main study. There was a significant difference for age, resulting in a difference in absolute forced expiratory volume in 1 second but no difference in asthma severity based on the forced expiratory volume in 1 second percentage predicted. Baseline BDP dose was comparable between groups, as were baseline values of mean FE(NO) (active: 38.6 +/- 25.6 ppb; placebo: 52.7 +/- 52.9 ppb). The degree of BDP dose reduction during the steroid-reduction and open-label phases was equivalent between the omalizumab and placebo-treated groups; subjects in the omalizumab- and placebo-treated groups had reduced their BDP dose by an average of 51% and 60%, respectively, at the end of the steroid-reduction phase and by 68% and 94%, respectively, by the end of the open-label period. In the active and placebo groups, 44% and 27% and 75% and 73% of subjects had stopped use of inhaled corticosteroids at the end of the steroid-reduction and open-label phases, respectively. There was no significant difference between the active and placebo groups during the steroid-stable phase for AUC of adjusted nitric oxide (1.31 +/- 1.511 vs 1.45 +/- 0.736). However, during the steroid-reduction phase, the variability of adjusted FE(NO) in the placebo-treated group was greater than that of the omalizumab-treated group at most visits, with a significant difference between groups for AUC of adjusted nitric oxide (0.88 +/- 0.69 vs 1.65 +/- 1.06). FE(NO) fell from 82.1 +/- 55.6 ppm at the end of the steroid-reduction phase to 33.3 +/- 21.6 ppb at the end of the open-label period in the placebo group who were placed on active omalizumab. This decrease occurred while the mean dose of BDP remained very low. Analysis of FE(NO) over 52 weeks of omalizumab treatment in the active group demonstrated that there was a significant reduction from baseline to the end of the open-label period (41.9 +/- 29.0 to 18.0 +/- 21.8 ppb) despite a high degree of steroid reduction. CONCLUSION: In this preliminary study based on FE(NO), a noninvasive marker of airway inflammation, treatment with omalizumab may inhibit airway inflammation during steroid reduction in children with allergic asthma. The degree of inhibition of FE(NO) was similar to that seen for inhaled corticosteroids alone, suggesting an antiinflammatory action for this novel therapeutic agent in asthma. This is in keeping with recent evidence that omalizumab inhibits eosinophilic inflammation in induced sputum and endobronchial tissue.

Anti-Asthmatic Agents↗

Efficacy of omalizumab, an anti-immunoglobulin E antibody, in patients with allergic asthma at high risk of serious asthma-related morbidity and mortality.

AIM: Add-on therapy with omalizumab, an anti-immunoglobulin E antibody, is effective in improving disease control in patients with allergic asthma of varying severity. The aim of the present study was to determine the efficacy of omalizumab in a subgroup of patients at high risk of serious asthma-related morbidity and mortality. METHODS: A meta-analysis was performed of three randomised, double-blind, placebo-controlled studies (studies 1, 2 and 3) that enrolled 1412 patients with moderate or severe allergic asthma, all requiring daily treatment with inhaled corticosteroids (ICS). Omalizumab was administered subcutaneously every 2 or 4 weeks at a total 4-weekly dose of at least 0.016 mg/kg/IgE [IU/ml]. Each study consisted of a 16-week steroid-stable phase and a 12-16-week steroid-reduction phase, followed by a 24-week extension phase (studies 1 and 2 only). The primary outcome measure was the annualised rate of significant asthma exacerbation episodes (sAEEs) during the steroid-stable phase for the pooled subgroup of 254 high-risk patients (omalizumab, n = 135; placebo, n = 119). sAEEs were those requiring a doubling of baseline ICS dose (studies 1 and 2 only) or use of systemic steroids (all three studies). RESULTS: Overall, the number of patients with at least one sAEE during the steroid-stable phase was reduced from 35% (42/119) with placebo to 18% (24/135) with omalizumab. Mean sAEE rates were 1.56 and 0.69 per patient-year, respectively, a reduction of 56% with omalizumab (p = 0.007). Similar reductions in exacerbations in favour of omalizumab were observed for the whole study period and for all AEEs. In those with a history of hospitalisation in the last year, 6/49 (12%) on placebo vs. 2/44 (4.5%) on omalizumab were re-hospitalised during the study period. Patients treated with omalizumab also showed significantly greater improvements from baseline in PEFR (p = 0.026), overall AQoL (p = 0.042) and mean nocturnal (p = 0.007) and mean total (p = 0.011) asthma symptom scores compared with placebo. CONCLUSIONS: In patients at high risk of serious asthma-related morbidity and mortality, treatment with omalizumab offers the potential to halve the rate of asthma exacerbations and improve disease control.

Adolescent↗

Omalizumab pretreatment decreases acute reactions after rush immunotherapy for ragweed-induced seasonal allergic rhinitis.

BACKGROUND: Rush immunotherapy (RIT) presents an attractive alternative to standard immunotherapy. However, RIT carries a much greater risk of acute allergic reactions, including anaphylaxis. OBJECTIVES: We hypothesized that omalizumab, a humanized monoclonal anti-IgE antibody, would be effective in enhancing both safety and efficacy of RIT. METHODS: Adult patients with ragweed allergic rhinitis were enrolled in a 3-center, 4-arm, double-blind, parallel-group, placebo-controlled trial. Patients received either 9 weeks of omalizumab (0.016 mg/kg/IgE [IU/mL]/mo) or placebo, followed by 1-day rush (maximal dose 1.2-4.0 mug Amb a 1) or placebo immunotherapy, then 12 weeks of omalizumab or placebo plus immunotherapy. RESULTS: Of the 159 patients enrolled, 123 completed all treatments. Ragweed-specific IgG levels increased >11-fold in immunotherapy patients, and free IgE levels declined >10-fold in omalizumab patients. Patients receiving omalizumab plus immunotherapy had fewer adverse events than those receiving immunotherapy alone. Post hoc analysis of groups receiving immunotherapy demonstrated that addition of omalizumab resulted in a 5-fold decrease in risk of anaphylaxis caused by RIT (odds ratio, 0.17; P = .026). On an intent-to-treat basis, patients receiving both omalizumab and immunotherapy showed a significant improvement in severity scores during the ragweed season compared with those receiving immunotherapy alone (0.69 vs 0.86; P = .044). CONCLUSION: Omalizumab pretreatment enhances the safety of RIT for ragweed allergic rhinitis. Furthermore, combined therapy with omalizumab and allergen immunotherapy may be an effective strategy to permit more rapid and higher doses of allergen immunotherapy to be given more safely and with greater efficacy to patients with allergic diseases.

Adolescent↗

Effect of omalizumab treatment on peripheral eosinophil and T-lymphocyte function in patients with allergic asthma.

BACKGROUND: Omalizumab is a recombinant monoclonal anti-IgE antibody with proven efficacy in allergic diseases and further anti-inflammatory potency in the treatment of asthma. OBJECTIVES: To explore the anti-inflammatory mechanism of omalizumab, we investigated the induction of immunologic changes leading to eosinophil apoptosis and examined T-lymphocyte cytokine profiles in patients with allergic asthma. METHODS: Nineteen patients with allergic asthma were enrolled and received omalizumab at a dose of at least 0.016 mg/kg/IgE (IU/mL) every 4 weeks. Peripheral eosinophils and T-lymphocyte cytokine profiles were evaluated by fluorescence-activated cell sorting before treatment (baseline), at 12 weeks of treatment, and 12 weeks after discontinuation of treatment with omalizumab or placebo. RESULTS: Markers of eosinophil apoptosis (Annexin V) were significantly increased in omalizumab recipients compared with placebo, whereas no changes in markers of necrosis (7-amino-actinomycin) or eosinophil activation CD69 or Fas receptor (CD95) were detected. GM-CSF+ lymphocytes were reduced in omalizumab recipients compared with placebo. Fewer IL-2+ and IL-13+ lymphocytes were evident in omalizumab recipients than in the placebo group. There were no significant differences in IL-5, IFN-gamma, or TNF-alpha between the omalizumab and placebo groups. CONCLUSION: These findings provide further evidence that omalizumab has additional anti-inflammatory activity demonstrated by induction of eosinophil apoptosis and downregulation of the inflammatory cytokines IL-2 and IL-13. Further studies are needed to determine the underlying mechanisms. CLINICAL IMPLICATIONS: These findings support the critical role of IgE in the regulation of inflammation in allergic asthma: influencing the inflammation is the key to control the more severe type of asthma.

Adult↗

Effects of omalizumab and budesonide on markers of inflammation in human bronchial epithelial cells.

BACKGROUND: Many patients with asthma have an IgE-mediated allergic component to the disease. Omalizumab, a monoclonal anti-IgE antibody, has demonstrated clinical efficacy in patients with allergic asthma. The effects of omalizumab on inflammation in asthma are not completely understood. OBJECTIVES: To evaluate the effects of omalizumab on allergen- and growth factor-stimulated proinflammatory cytokine and nitric oxide (NO) production in human bronchial epithelial cells (BECs) and to compare them to the effects of budesonide, a corticosteroid with known anti-inflammatory properties. METHODS: Human BECs were stimulated in duplicate with interleukin 1beta (IL-1beta), 100 U/mL; ragweed, 10 microg/mL; dust mite, 1000 AU; and epithelial growth factor, 40 ng/mL; and either 10(-7) M budesonide or 0.1 microg/mL of omalizumab in a 4% dust mite atopic serum medium for 6 and 24 hours in 5% carbon dioxide at 37 degrees C. Tumor necrosis factor alpha and transforming growth factor betaexpression and production and IL-4, IL-13, and NO production were assayed using gene-specific messenger RNA or sensitive enzyme-linked immunosorbent assays. RESULTS: Omalizumab inhibited the expression and of production proinflammatory cytokines and growth factor in antigen-stimulated BECs at 6 and 24 hours. Production of NO was inhibited at 6 hours and increased at 24 hours by omalizumab and budesonide. CONCLUSIONS: The effects of omalizumab were similar to those of budesonide. These results, consistent with previously reported evidence of anti-inflammatory effects of omalizumab, demonstrate that omalizumab may reduce airway inflammation and probably contributes to decreased airway remodeling in patients with asthma.

Anti-Inflammatory Agents↗

Omalizumab is effective in the long-term control of severe allergic asthma.

BACKGROUND: Previous reports show that addition of omalizumab to standard therapy reduces asthma exacerbations and simultaneously decreases use of inhaled corticosteroids (ICSs) and rescue medication in patients with allergic asthma. OBJECTIVE: To determine the effect of omalizumab on long-term disease control in patients with severe allergic asthma. METHODS: The present study concerns the 24-week, double-blind extension phase to a previous 28-week core study in which patients received subcutaneous omalizumab or matching placebo (at least 0.016 mg/kg/IgE [IU/mL] every 4 weeks) for 16 weeks in addition to their existing ICS therapy (beclomethasone dipropionate [BDP]; steroid-stable phase), followed by a 12-week phase in which controlled attempts were made to gradually reduce ICS therapy (steroid-reduction phase). During the extension phase patients were maintained on randomized treatment (omalizumab or placebo) and the lowest sustainable dose of BDP. The use of other asthma medications was permitted during the extension phase. Investigators were also allowed to switch patients from BDP to other ICS medications if considered necessary. RESULTS: A total of 460 patients (omalizumab, n = 245; placebo, n = 215) entered the extension phase. Overall, omalizumab-treated patients experienced significantly fewer exacerbations vs placebo during the extension phase (0.60 and 0.83 exacerbations per patient, respectively; P = 0.023), despite a sustained significant reduction in their use of ICS (mean BDP equivalent dose: omalizumab, 227 microg/d; placebo, 335 microg/d; P < 0.001). Treatment with omalizumab was well tolerated and the incidence of adverse events was similar in both treatment groups. CONCLUSIONS: These results indicate that omalizumab is effective in the long-term control of severe allergic asthma.

Administration, Intranasal↗

Omalizumab: a recombinant humanized anti-IgE antibody for allergic asthma.

PURPOSE: The pharmacology, efficacy, dosage, adverse events, and economics of omalizumab are discussed. SUMMARY: Omalizumab, a recombinant DNA-derived humanized monoclonal antibody, binds to the C epsilon3 domain of immunoglobulin E (IgE) and forms complexes that inhibit the immune system's response to allergens by averting IgE-mediated inflammatory changes. Omalizumab exhibits a similar pharmacokinetic profile in adults, adolescents, and children. Omalizumab is indicated for adults and adolescents 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. Because of the limited data regarding the safety and effectiveness of omalizumab in children, the drug is indicated for patients 12 years of age or older. The recommended starting dosage is 150-375 mg s.c. every two or four weeks. Dosages and frequency of dose administration are determined by total serum IgE level, measured before the start of treatment, and body weight. Omalizumab is generally well tolerated in adults and children with allergic asthma. Adverse events most commonly observed are injection-site reaction, viral infection, upper-respiratory-tract infection, sinusitis, headache, and pharyngitis. Three large phase III clinical trials demonstrated that omalizumab is more effective than placebo in controlling moderate to severe allergic asthma in patients who have poor disease control or exacerbations despite recommended therapy. Currently, there are no clinical comparisons of omalizumab with other standard treatments for asthma; therefore, it is difficult to determine its overall place in therapy. CONCLUSION: Omalizumab should be considered as a second-line therapy for patients with moderate to severe persistent allergic asthma.

Adolescent↗

The role of omalizumab in the treatment of severe allergic asthma.

BACKGROUND: A novel anti-immunoglobulin E (anti-IgE) therapy for asthma, omalizumab, has been approved for use in Canada. OBJECTIVE: To review the basic and clinical data for omalizumab, and to examine its possible role for asthma management in Canada. METHODS: A literature search from 1960 to 2006 was conducted in MEDLINE to identify studies of omalizumab. In addition, abstracts from recent respiratory and allergy scientific meetings were sought, and any unpublished data were requested from the manufacturer. A consensus panel of respiratory and allergy specialists reviewed and summarized the data, and derived a set of recommendations for omalizumab use. RESULTS: Omalizumab is a humanized monoclonal antibody designed to bind to the C epsilon 3 domain of the IgE molecule, forming soluble immune complexes that are cleared by the reticuloendothelial system. Subcutaneous injections, given at two- or four-week intervals at the recommended dose, result in a rapid decrease in free circulating IgE levels. In two phase III clinical trials of 1405 adult and adolescent patients with moderate to severe asthma maintained on moderate doses of inhaled corticosteroids (ICS), omalizumab reduced exacerbation rates compared with placebo, and was associated with improved symptoms and a greater corticosteroid-sparing effect. In a trial of 419 patients with severe disease that was uncontrolled despite the use of high-dose ICS and concurrent long-acting beta2-agonists, severe exacerbations were 50% less frequent in omalizumab-treated patients than in control subjects. Retrospective analyses have identified the characteristics of patients most likely to respond to omalizumab treatment. RECOMMENDATIONS: Omalizumab may be considered as a potential adjunctive therapy in atopic patients with severe asthma uncontrolled by conventional therapy with optimal doses of ICS and appropriate adjunctive therapy (eg, long-acting beta2-agonists). Typically, patients are identified by the need for frequent short course or continuous oral corticosteroids. Therapy should be initiated only after review by a specialist to confirm the diagnosis and that conventional therapy is optimal.

Anti-Asthmatic Agents↗

Omalizumab: a novel therapy for allergic asthma.

OBJECTIVE: To review the pharmacology, efficacy, and safety of omalizumab, focusing on the treatment of allergic asthma. DATA SOURCES: A MEDLINE search (1966-November 2003) was conducted using the key words omalizumab, Xolair, and Rhu-MAB25, with studies limited to those in humans and published in English. References of identified articles were reviewed for additional citations. STUDY SELECTION AND DATA EXTRACTION: Clinical trials evaluating the pharmacology, efficacy, and safety of omalizumab for treatment of allergic asthma in patients aged >or=12 years were selected. Clinical trials examining utility in pediatric patients were also reviewed. DATA SYNTHESIS: Omalizumab's ability to form complexes with unbound immunoglobulin E (IgE) translates into decreased unbound serum IgE levels and high-affinity IgE receptors on basophils, as well as attenuation of early and late allergic response in patients with allergic asthma. Results of clinical trials demonstrated that omalizumab administered subcutaneously is a safe and effective treatment for moderate to severe allergic asthma. Generally, omalizumab has a mild adverse effect profile. Omalizumab may be particularly useful for treatment of moderate to severe allergic asthma in patients who are poorly controlled on conventional therapy, experience adverse effects secondary to high-dose or prolonged corticosteroid treatment, or who have frequent exacerbations because of poor medication adherence. The high cost associated with omalizumab treatment may be prohibitive for some patients, thereby limiting its utility. CONCLUSIONS: Omalizumab is a safe and effective therapy for treatment of moderate to severe allergic asthma in difficult-to-treat, high-risk patients.

Anti-Allergic Agents↗

Predicting response to omalizumab, an anti-IgE antibody, in patients with allergic asthma.

STUDY OBJECTIVE: To determine baseline characteristics predictive of response to omalizumab, an anti-IgE antibody, in patients with allergic asthma. DESIGN: Pooled analysis of two multicenter, double-blind, randomized, placebo-controlled phase III studies with omalizumab. PATIENTS: One thousand seventy allergic asthma patients symptomatic despite moderate-to-high doses (mean, 725 micro g/d) of inhaled beclomethasone dipropionate (BDP). INTERVENTIONS: Omalizumab (n = 542) or placebo (n = 528) were administered at a 4-weekly subcutaneous dose of at least 0.016 mg/kg/IgE (IU/mL) for 16 weeks in addition to stable BDP therapy. MEASUREMENTS AND RESULTS: Univariate logistic regression was performed to explore baseline variables predictive of best response. Various aspects of response (reduced symptom scores, reduced usage of rescue medication, improved lung function, improved quality of life [QoL]) were explored as well as a composite definition of response (response in at least one of these four aspects with no asthma exacerbation during 16 weeks of treatment). Time to onset of response as well as the ability to predict eventual response were also determined for the composite definition of response. A consistent pattern of predictive covariates was seen over all definitions of response (except for QoL). For the composite definition, a history of emergency asthma treatment in the past year was the factor most predictive (p = 0.015) of best response on active treatment (response rate for those with such history was 67% for omalizumab and 42% for placebo; for those without a history the response rates were 63% and 54%, respectively). Another factor predictive of best response on active treatment was high BDP dose (p = 0.037; response rate for those treated with >or= 800 micro g/d was 65% for omalizumab and 40% for placebo; for those treated with < 800 micro g/d, the response rates were 63% and 55%, respectively). A low FEV(1) was also predictive (p = 0.072; response rates for those with FEV(1) or= 65% predicted, the response rates were 67% and 53%, respectively). Seventy-six percent of patients had at least one of these factors. This subgroup showed odds of being a responder (composite definition) 2.25 times higher (95% confidence interval, 1.68 to 3.01) than placebo. Some 38% of patients treated with omalizumab showed a response (composite definition) at the first evaluation time point at 4 weeks, increasing to 64% at week 16 (vs 48% for placebo; p < 0.001). Among omalizumab responders at 16 weeks, only 61% had responded at 4 weeks whereas 87% had responded at 12 weeks. CONCLUSIONS: Patients who benefit most when omalizumab is administered as add-on therapy are those receiving high doses of BDP, those with a history of frequent emergency asthma treatment, and those with poor lung function. Patients should be treated with omalizumab for a minimum duration of 12 weeks.

Adolescent↗

Omalizumab: a monoclonal anti-IgE antibody.

OBJECTIVES: To describe allergic asthma and allergic rhinitis pathophysiology and review the pharmacologic, pharmacokinetic, pharmacodynamic, efficacy, and safety data for omalizumab. METHODS: MEDLINE, In-Process & Other Non-Indexed Citations, and EMBASE Drugs & Pharmacology were searched using olizumab, omalizumab, E25, rhuMAb-E25, and anti-IgE. Combinations of rhinitis, asthma, and IgE captured information on disease pathophysiology. RESULTS: Omalizumab is a monoclonal antibody targeting the high-affinity receptor binding site on human immunoglobulin (Ig)E. Bound IgE is not available for basophil binding, degranulation is attenuated, and allergic symptoms are reduced. In asthma trials, omalizumab reduced inhaled corticosteroid and rescue medication requirements and improved asthma control and asthma quality of life in moderate to severe allergic asthmatics with disease poorly controlled by inhaled corticosteroids. In trials of patients with poorly controlled moderate to severe seasonal allergic rhinitis (SAR), omalizumab reduced the severity of exacerbations and rescue medication use, and improved rhinitis-related quality of life. Benefits were also observed in trials utilizing combinations of immunotherapy and omalizumab for SAR and in trials of perennial allergic rhinitis (PAR). Omalizumab has been well tolerated. Although malignant neoplasms have been observed in treated patients, they were likely not related to omalizumab therapy. CONCLUSIONS: Omalizumab has demonstrated efficacy in children, adults, and adolescents with uncontrolled moderate to severe allergic asthma and allergic rhinitis. Long-term safety beyond 52 weeks needs continued evaluation.

Antibodies, Anti-Idiotypic↗

Omalizumab rapidly decreases nasal allergic response and FcepsilonRI on basophils.

BACKGROUND: Omalizumab is a monoclonal anti-IgE antibody that is effective for the treatment of allergic respiratory disorders; however, its onset of action is unknown. OBJECTIVE: This study was designed to determine the onset of action of omalizumab through the use of a challenge model to determine time-dependent inhibition of ragweed-induced changes in nasal volume as well as correlate the kinetics of omalizumab-induced decreases in serum free IgE and FcepsilonRI receptors on basophils. METHODS: We conducted a 6-week, randomized, double-blind, placebo-controlled study of 24 rhinitic patients with ragweed allergy. After PD(30) ragweed nasal allergen challenge, patients received either omalizumab, approximately 0.016 mg/kg per IgE (IU/mL), or placebo at days 0 and 28 and were rechallenged with ragweed PD(30) dose biweekly. FcepsilonRI expression on blood basophils was determined by flow cytometry at baseline and 7, 14, 28, and 42 days after treatment. IgE levels were measured at baseline and on days 3, 28, and 42. RESULTS: Mean IgE levels decreased by 96% (P <.001) from baseline within 3 days in the omalizumab group. Baseline 30% ragweed-induced nasal volume response was decreased to 20.4% at 7 to 14 days (P <.001) and 12.2% at 35 to 42 days (P <.001) for the omalizumab group. There was a median decrease in basophil FcepsilonRI expression of 73% (P <.001) in the omalizumab group, with maximum inhibition occurring within 14 days of treatment. No significant changes in IgE levels, nasal allergen challenge responses, or basophil FcepsilonRI expression were observed throughout the study in the placebo group. CONCLUSIONS: Our study showed that the onset of action by omalizumab in blunting ragweed-induced nasal responses is within 2 weeks, and this response was associated with 2 putative mechanisms of action: decreased serum free IgE and decreased FcepsilonRI receptor expression on immune effector cells.

Adult↗

Accuracy of US Food and Drug Administration-cleared IgE antibody assays in the presence of anti-IgE (omalizumab).

BACKGROUND: Although serological IgE measurements can aid in efficacy assessment of patients with asthma on omalizumab (Xolair [Genentech, Inc., South San Francisco, Calif]; humanized IgG1 antihuman IgE Fc), its effect on clinically used IgE assay performance is unknown. OBJECTIVE: This study investigated the hypothesis that IgE:IgG-anti-IgE immune complex formation after omalizumab administration diminishes accuracy and increases variability of IgE assays performed in diagnostic immunology laboratories. METHODS: Plasma from 4 atopic adults was incubated with omalizumab (50 or 200 molar excess to IgE) or buffer. Paired specimens were sent masked to 159 clinical laboratories in the College of American Pathologists Diagnostic Allergy Proficiency Survey (cycles SE-C-2003, SE-A-2005). Inhibitory effects produced by omalizumab on accuracy and reproducibility of US Food and Drug Administration (FDA)-cleared total and allergen-specific IgE assays were computed by using national proficiency survey data. RESULTS: Total serum IgE levels measured in the 2 ImmunoCAP assays were minimally reduced (2.4-9.0%) by the presence of omalizumab, whereas 5 other assays showed marked reductions from 12.5% to 67.2% (P < .001) that increased in proportion to total serum IgE levels. The degree of interference was not large enough to produce detectable misclassification of IgE antibody results (positive to negative) in 4 multiallergen screening assays. Of 11 FDA-cleared IgE antibody assays, only 3 (ImmunoCAP, UniCAP, Immulite-2000) generated quantitative IU/mL results that could be assessed for interference. Omalizumab produced 0.8% to 27.8% reduction in allergen-specific IgE levels across 8 allergen specificities. CONCLUSION: Although as much as 62% loss in accuracy was observed in FDA-cleared human IgE assays, the ImmunoCAP system was sufficiently robust to provide accurate and reproducible total and allergen-specific IgE antibody results in a clinical setting where therapeutic levels of omalizumab are present in serum. CLINICAL IMPLICATIONS: Accurate monitoring of total and allergen-specific IgE, together with free IgE levels, in serum from patients on omalizumab may help optimize dosing and maximize the efficacy of Xolair therapy.

Adult↗