Omalizumab: a novel therapy for allergic asthma

Effect of omalizumab treatment on peripheral nerves in patients with chronic spontaneous urticaria

Aim: Chronic spontaneous urticaria (CSU) is characterised by itchy, red and raised lesions that appear as an attack without any cause and last for six weeks or longer. Omalizumab is a humanised monoclonal antibody that selectively binds to the Ce3 moiety of circulating IgE and is indicated for the treatment of resistant CSU. In this study, we aimed to investigate whether there was peripheral nervous system involvement in patients with chronic urticaria receiving omalizumab treatment.Methods: Forty-seven patients who were treated with omalizumab for CSU were included in the study. Electrophysiological measurements were performed following a neurological examination before treatment and at three months after omalizumab treatment. In nerve conduction tests, eight different nerves were studied in four extremities (total 16 nerves). During these studies, two motor and two sensory nerves (median and ulnar) in the upper extremities, and two motor (tibial and common peroneal) and two sensory nerves (sural and superficial peroneal) in the lower extremities were analysed.Results: No pathological electrophysiological findings supporting neuropathy were detected in any of the measurements performed before and after treatment. When the nerve conduction velocity, amplitude and latency values ​​of all examined nerves were compared, no significant difference was found between the pre- and post-treatment values.Conclusions: It can be considered that omalizumab has no effect on peripheral nerves, and it is a safe and well tolerated agent in terms of both peripheral nerves and neurological structure.

Specialized proresolving mediators (SPMs) inhibit human B-cell IgE production

Specialized proresolving mediators (SPMs) constitute a recently recognized class of bioactive molecules thatpromote the resolution of inflammation. We recently reported that the SPMs resolvin D1 (RvD1) and 17-hydroxydocosahexaenoic acid (17-HDHA) promote the differentiation of IgG-secreting B cells and enhance antibody-mediated immune responses. However, there is an important knowledge gap regarding whether or not SPMs regulate human B-cell IgE production, which is the key effector in diseases such as asthma and allergy. Therefore, we investigated whether a panel of diverse SPMs influences B-cell IgE production. An important finding was that 17-HDHA and RvD1 inhibit IgE production by human B cells and suppress the differentiation of naïve B cells into IgE-secreting cells by specifically blocking epsilon germline transcript. This effect is specific to human IgE, as the SPMs do not inhibit production of IgM and IgG and did not suppress other IL-4-upregulated genes. 17-HDHA and RvD1 act by stabilizing the transcriptional repressor B-cell lymphoma 6, which competes with STAT6 for binding at the epsilon germline transcript promoter. Overall, these new findings demonstrate that certain SPMs inhibit the differentiation of IgE-producing B cells, without being broadly immune suppressive, representing a novel class of potential therapeutics for IgE-driven diseases such as asthma and allergy.

Monoclonal antibodies based on hybridoma technology

Based on the size and scope of the present global market for medicine, monoclonal antibodies (mAbs) have a very promising future, with applications for cancers through autoimmune ailments to infectious disease. Since mAbs recognize only their target antigens and not other unrelated proteins, pinpoint medical treatment is possible. Global demand is dramatically expanding. Hybridoma technology, which allows production of mAbs directed against antigens of interest is therefore privileged. However, there are some pivotal points for further development to generate therapeutic antibodies. One is selective generation of human mAbs. Employment of transgenic mice producing human antibodies would overcome this problem. Another focus is recognition sites and conformational epitopes in antigens may be just as important as linear epitopes, especially when membrane proteins such as receptors are targeted. Recognition of intact structures is of critical importance for medical purposes. In this review, we describe patent related information for therapeutic mAbs based on hybridoma technology and also discuss new advances in hybridoma technology that facilitate selective production of stereospecific mAbs.

Effects of acupuncture-like transcutaneous electrical nerve stimulation on children with asthma

OBJECTIVE

To evaluate the effects of acupuncture-like transcutaneous electrical nerve stimulation (AL-TENS) on children with asthma.

METHODS

After an 8-week run-in period, the experimental group were assigned to treatment with AL-TENS, whereas the control group did not receive AL-TENS. A total of 43 children with asthma were recruited from a hospital and an elementary school. All the cases had been diagnosed as having asthma by physicians. The outcome measures included pulmonary function tests (PFTs), heart rate turbulence (HRT), heart rate variability (HRV), and pediatric asthma quality-of-life questionnaire (PAQLQ).

RESULTS

After 8 weeks of AL-TENS, there were no significant differences on forced vital capacity (FVC), FEV₁/FVC, and peak expiratory flows (PEFs) between the two groups. The HRT is the physiological, biphasic response of the sinus node to premature ventricular contractions. In the experimental group, the mean HRT was statistically significant between pretest and posttest. The HRV and the PAQLQ showed no difference, but in the experimental group, the subscale of the PAQLQ (particularly activity) improved significantly more than the pretest scores. Furthermore, there were no differences in PFTs and HRV after 8 weeks of AL-TENS between the two groups.

CONCLUSIONS

The PAQLQ activities of the experimental group improved significantly more than those of the control group. Reasons may include: 1) the asthma cases were stable and the cases were on stable status and 2) the degree of airway remodeling was less. It is suggested that in the future, treatment frequency and the long-term follow-up for evaluating the effects of AL-TENS on children with asthma should also be considered.

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.

Patient-reported outcomes among omalizumab and salmeterol/fluticasone combination therapy patients

BACKGROUND

Some asthma patients remain poorly controlled despite receiving care consistent with treatment guidelines.

OBJECTIVE

This study compared the ability to sleep, work, and participate in leisure activities among subjects with immunoglobulin E-mediated (allergic) asthma initiating omalizumab (omalizumab start group) with subjects receiving moderate-to-high doses of salmeterol/fluticasone combination therapy, who continued on salmeterol/fluticasone combination therapy for at least a year without adding omalizumab (salmeterol/fluticasone combination continuation group).

METHODS

Subjects completed an Internet-based screener and, if eligible, an Internet-based questionnaire. A propensity score model was utilized in the analysis. Group differences were assessed through logistic and linear regression models. Analyses were adjusted for propensity score quintile, how subjects heard about the study, and responses to retrospective single-item questions.

RESULTS

The analysis population included 86 omalizumab start group subjects and 436 salmeterol/fluticasone combination continuation subjects, recruited from June to November 2006. In the adjusted analyses, the omalizumab start group was more than twice as likely to have controlled asthma as measured by the Asthma Control Test (odds ratio, 2.62; p = 0.005). The omalizumab start group had significantly fewer sleep disturbances as measured by the Jenkins Sleep Evaluation Questionnaire (least-square means difference, -1.65;p = 0.004), less activity impairment as measured by the Work Productivity Activity Impairment-Asthma Scale (least-square means difference, -13.36;p < 0.001), and less difficulty in activities as measured by the Valued Life Activities Questionnaire (least-square means difference, -0.24; p < 0.001).

CONCLUSION

Asthma subjects who started taking omalizumab reported more improvement in asthma control, fewer sleep problems, less activity impairment, and less difficulty with activities than a similar cohort of subjects who continued taking salmeterol/fluticasone combination therapy.

[Targeted immunologic therapies for severe asthma]

Better understanding of the cellular and molecular mechanisms of asthma have made it possible to envision a large number of new treatment targets. Clinical trials assessing some of these targets were recently published. The results of these trials were often disappointing. For example, parenteral administration of anti-interleukin-5 antibodies diminished bronchial eosinophilic inflammation but without improving either asthma symptoms or bronchial hyperreactivity. Other treatments are promising but have not yet been proved effective in patients with asthma: open studies with anti-TNF alpha antibodies are interesting but the efficacy of this treatment strategy remains uncertain and must be validated against placebo. The first targeted treatment approved for severe difficult-to-control allergic asthma is an anti-IgE monoclonal antibody (omalizumab).

Drugs, their targets and the nature and number of drug targets

What is a drug target? And how many such targets are there? Here, we consider the nature of drug targets, and by classifying known drug substances on the basis of the discussed principles we provide an estimation of the total number of current drug targets.

Safety and tolerability of omalizumab (Xolair), a recombinant humanized monoclonal anti-IgE antibody

Omalizumab (Xolair) is a humanized monoclonal antibody designed to bind specifically to immunoglobulin (Ig)E. It is indicated in the United States for the treatment of adolescent and adult patients (>or=12 yr) 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 was evaluated in an extensive clinical development program that included 12 controlled phase IIB/III clinical trials with more than 5,243 patients who were appropriate for inclusion in the safety analysis (all ages in all controlled studies). In these studies, omalizumab had an adverse event profile comparable to that of the control group (i.e., placebo or standard therapy). Data presented in this article supports omalizumab as a safe and well-tolerated agent for the treatment of IgE-mediated asthma.

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.