Balancing safety and efficacy in the treatment of pediatric asthma

Inhaled steroid inhibits development of total and mite IgE

Serum levels of total immunoglobulin E (IgE) and allergen-specific IgE are related to asthma severity and risk factors for persistent asthma in childhood wheezing. Inhaled corticosteroids (ICS) have been the most effective therapy in children with asthma, as well as in adults. The serum levels of total and mite specific IgE in children with asthma and the effects on IgE levels of beclomethasone dipropionate (BDP) treatment on IgE levels in asthmatic children were investigated. First, a cross-sectional study of 255 children with asthma was carried out to measure IgE levels. Children under three years of age with asthma who were negative for Df-specific IgE were then treated with BDP or disodium cromoglycate (DSCG) as controls for one year. Serum IgE levels, numbers of eosinophils in peripheral blood and clinical variables were determined before and after treatment. After one-year DSCG treatment, the total IgE levels increased significantly, whereas the levels remained the same during BDP treatment. Five of 22 (23%) patients in the DSCG-treated group became positive for Df-specific IgE; however, only one of 13 (8%) in the BDP-treated group became positive. Taken together, ICS therapy may modulate the levels of total IgE and allergen-specific IgE.

TLR9-based immunotherapy for allergic disease

A significant amount of data generated over the last few years supports the contention that Toll-like receptor (TLR) 9-based immunotherapy is effective in the prevention and treatment of animal models of allergic disorders. We will review here our experience with two distinct therapeutic strategies: TLR9-based immunomodulation and TLR9-based vaccination. Immunomodulation of allergic inflammation by TLR9 ligand (TLR9-L) is transient. It prevents both the early and late phases of the allergic reaction in experimental models of allergic asthma, rhinitis, and conjunctivitis. It also reverses ongoing allergic inflammation. Indoleamine 2.3-dioxygenase, the rate-limiting enzyme of tryptophan, is induced by TLR9-L and mediates, in part, these anti-inflammatory effects. TLR9-based immunomodulation is independent of allergens and, therefore, has a potential therapeutic advantage in a broad spectrum of allergic patients. On the other hand, TLR9-based vaccination therapy is an allergen-specific mode of immunotherapy, which provides long-term inhibition of allergen-specific hypersensitivities. Current clinical trials with TLR9-based immunotherapy demonstrate high immunogenic and therapeutic efficacy, as well as improved safety when compared with conventional allergen desensitization. Thus, if proven efficient, therapeutic strategies with TLR9-L may revolutionize the current treatment of allergic diseases.

Variability in asthma severity in pediatric subjects with asthma previously receiving short-acting beta2-agonists

OBJECTIVE

An analysis of 5 double-blinded, randomized, 12-week asthma trials was undertaken to evaluate pediatric subjects (4 to 11 years; n=276) who were previously receiving short-acting beta2-agonists alone and subsequently received treatment with placebo. At baseline, all subjects met National Asthma Education and Prevention Program criteria for moderate/severe asthma.

STUDY DESIGN

Asthma severity was categorized individually for symptoms, albuterol use, and morning peak expiratory flow and then overall taking into account all three parameters.

RESULTS

Subjects spent the majority of weeks (55%) in the moderate/severe category. Subjects spent approximately 48%, 31%, and 22% of weeks in intermittent, mild, and moderate/severe categories and 57%, 27%, and 15% of weeks, respectively, based on asthma symptoms and albuterol use. Subjects spent approximately 62%, 31%, and 8% of weeks in intermittent/mild, moderate, and severe categories, based on peak expiratory flow; however, >35% of subjects exhibited >or=15 changes in asthma severity classification, based on peak expiratory flow.

CONCLUSIONS

Asthma is a disease with varying symptomatology, and pediatric subjects frequently move between severity categories, especially in children with inadequate asthma control. These data also emphasize that asthma severity cannot be determined in many pediatric subjects by discrete, point-in-time assessments of lung function, albuterol use, or asthma symptoms. Failure to recognize this problem may contribute to underestimation of disease severity in pediatric subjects.

The safety of twice-daily treatment with fluticasone propionate and salmeterol in pediatric patients with persistent asthma

BACKGROUND

For children older than 5 years with asthma who remain symptomatic despite inhaled corticosteroid (ICS) therapy, the preferred treatment is to add an inhaled long-acting beta2-agonist vs increasing the ICS dose.

OBJECTIVE

To compare the safety of twice-daily treatment with inhaled fluticasone propionate plus the inhaled long-acting beta2-agonist salmeterol with that of fluticasone propionate used alone in children aged 4 to 11 years with persistent asthma.

METHODS

A randomized, multicenter, double-blind, active-controlled, parallel-group study in 203 children with persistent asthma who were symptomatic during ICS therapy. Patients received fluticasone propionate-salmeterol (100/50 microg) or fluticasone propionate (100 microg) alone twice daily for 12 weeks.

RESULTS

The safety profile of fluticasone propionate-salmeterol was similar to that of fluticasone propionate alone. The overall incidence of adverse events was 59% for fluticasone propionate-salmeterol and 57% for fluticasone propionate. Both treatments were well tolerated. Two patients receiving fluticasone propionate-salmeterol and 5 receiving fluticasone propionate withdrew from the study because of worsening asthma. Changes in heart rate, blood pressure, and laboratory variables were infrequent and were similar between treatments. No patients had clinically significant abnormal electrocardiographic findings during treatment. Geometric mean 24-hour urinary cortisol excretion at baseline and after 12 weeks of treatment was comparable within and between groups; no patient in either group had abnormally low 24-hour urinary cortisol excretion after 12 weeks of treatment. The incidence of withdrawals due to asthma exacerbations was 2% in the fluticasone propionate-salmeterol group and 5% in the fluticasone propionate group.

CONCLUSIONS

In pediatric patients with persistent asthma, fluticasone propionate-salmeterol twice daily was well tolerated, with a safety profile similar to that of fluticasone propionate used alone.

Disodium cromoglycate suppresses the induction of cysteinyl leukotriene synthesis during granulocytic differentiation in HL-60 cells

OBJECTIVES

Disodium cromoglycate (DSCG) and nedocromil sodium are anti-asthma drugs that have a variety of physiological and biological effects. We examined whether DSCG affects the induction of cysteinyl Leukotriene (cysLT) synthesis during dimethyl sulfoxide (DMSO)-induced granulocytic differentiation in HL-60 cells.

METHODS

HL-60 cells were differentiated to mature granulocyte-like cells by DMSO in the presence or absence of DSCG for 5 days. Then, we measured A23187-stimulated production of LTC4, an initial product of cysLTs. We also examined the mRNA expression and enzyme activity of LTC4 synthase and other LT-synthetic enzymes.

RESULTS

The amount of LTC4 production was 732.0+/-19.0 pg/10(6) cells in DMSO-differentiated HL-60 cells. The value was significantly decreased to 420.7+/-22.7 pg/10(6) cells in the presence of DSCG at 100 microg/ml. The DMSO-induced mRNA expression and enzyme activity of LTC4 synthase was also suppressed by DSCG.

CONCLUSIONS

Our results indicate that DSCG suppresses the DMSO-induced LTC4 synthase-activity by inhibiting mRNA expression of LTC4 synthase, which might be a novel anti-allergic action of DSCG.

Immunostimulatory sequence oligodeoxynucleotide-based vaccination and immunomodulation: two unique but complementary strategies for the treatment of allergic diseases

Despite a number of effective pharmaceutical options for the prevention and treatment of the pathophysiologic responses that occur in sensitized patients on allergen exposure, the termination of allergic hypersensitivities remains an elusive therapeutic goal. Traditional immunotherapy with allergen extracts is the only currently used intervention that has been shown to induce allergen tolerance, but it has a limited scope of efficacy. However, recent studies suggest that immunostimulatory sequence oligodeoxynucleotide (ISS-ODN) -based interventions might offer an alternative and potentially more effective means for extinguishing T (H)2-biased hypersensitivities. Three basic ISS-ODN -based immunotherapeutic strategies have been studied to date. Immunization with allergen mixed with ISS- ODN, immunization with allergen -ISS- ODN conjugates, and immunomodulation with ISS- ODN alone all have proved efficacy in the attenuation of the allergic phenotype in mice. Preliminary results with allergen -ISS- ODN conjugate vaccines in allergic patients have also been encouraging. This article will provide our perspective on the application of ISS-ODN -based vaccination and immunomodulation to the treatment of atopic diseases and the immunologic basis for their antiallergic activities.