Triple vs Dual Inhaler Therapy and Asthma Outcomes in Moderate to Severe Asthma: A Systematic Review and Meta-analysis.

IMPORTANCE: The benefits and harms of adding long-acting muscarinic antagonists (LAMAs) to inhaled corticosteroids (ICS) and long-acting ß2-agonists (LABAs) for moderate to severe asthma remain unclear. OBJECTIVE: To systematically synthesize the outcomes and adverse events associated with triple therapy (ICS, LABA, and LAMA) vs dual therapy (ICS plus LABA) in children and adults with persistent uncontrolled asthma. DATA SOURCES: MEDLINE, Embase, CENTRAL, ICTRP, FDA, and EMA databases from November 2017, to December 8, 2020, without language restriction. STUDY SELECTION: Two investigators independently selected randomized clinical trials (RCTs) comparing triple vs dual therapy in patients with moderate to severe asthma. DATA EXTRACTION AND SYNTHESIS: Two reviewers independently extracted data and assessed risk of bias. Random-effects meta-analyses, including individual patient-level exacerbation data, were used. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach was used to assess certainty (quality) of the evidence. MAIN OUTCOMES AND MEASURES: Severe exacerbations, asthma control (measured using the Asthma Control Questionnaire [ACQ-7], a 7-item list with each item ranging from 0 [totally controlled] to 6 [severely uncontrolled]; minimal important difference, 0.5), quality of life (measured using the Asthma-related Quality of Life [AQLQ] tool; score range, 1 [severely impaired] to 7 [no impairment]; minimal important difference, 0.5), mortality, and adverse events. RESULTS: Twenty RCTs using 3 LAMA types that enrolled 11 894 children and adults (mean age, 52 years [range, 9-71 years]; 57.7% female) were included. High-certainty evidence showed that triple therapy vs dual therapy was significantly associated with a reduction in severe exacerbation risk (9 trials [9932 patients]; 22.7% vs 27.4%; risk ratio, 0.83 [95% CI, 0.77 to 0.90]) and an improvement in asthma control (14 trials [11 230 patients]; standardized mean difference [SMD], -0.06 [95% CI, -0.10 to -0.02]; mean difference in ACQ-7 scale, -0.04 [95% CI, -0.07 to -0.01]). There were no significant differences in asthma-related quality of life (7 trials [5247 patients]; SMD, 0.05 [95% CI, -0.03 to 0.13]; mean difference in AQLQ score, 0.05 [95% CI, -0.03 to 0.13]; moderate-certainty evidence) or mortality (17 trials [11 595 patients]; 0.12% vs 0.12%; risk ratio, 0.96 [95% CI, 0.33 to 2.75]; high-certainty evidence) between dual and triple therapy. Triple therapy was significantly associated with increased dry mouth and dysphonia (10 trials [7395 patients]; 3.0% vs 1.8%; risk ratio, 1.65 [95% CI, 1.14 to 2.38]; high-certainty evidence), but treatment-related and serious adverse events were not significantly different between groups (moderate-certainty evidence). CONCLUSIONS AND RELEVANCE: Among children (aged 6 to 18 years) and adults with moderate to severe asthma, triple therapy, compared with dual therapy, was significantly associated with fewer severe asthma exacerbations and modest improvements in asthma control without significant differences in quality of life or mortality.

The effect of omega-3 fatty acids on bronchial hyperresponsiveness, sputum eosinophilia, and mast cell mediators in asthma.

BACKGROUND: Omega-3 fatty acid supplements have been reported to inhibit exercise-induced bronchoconstriction (EIB). It has not been determined whether omega-3 supplements inhibit airway sensitivity to inhaled mannitol, a test for bronchial hyperresponsiveness (BHR) and model for EIB in people with mild to moderate asthma. METHODS: In a double-blind, crossover trial, subjects with asthma who had BHR to inhaled mannitol (n = 23; 14 men; mean age, 28 years; one-half taking regular inhaled corticosteroids) were randomized to omega-3 supplements (4.0 g/d eicosapentaenoic acid and 2.0 g/d docosahexaenoic acid) or matching placebo for 3 weeks separated by a 3-week washout. The primary outcome was the provoking dose of mannitol (mg) to cause a 15% fall in FEV1 (PD15). Secondary outcomes were sputum eosinophil count, spirometry, Asthma Control Questionnaire (ACQ) score, serum triacylglyceride level, and lipid mediator profile in urine and serum. RESULTS: PD15 (geometric mean, 95% CI) to mannitol following supplementation with omega-3s (78 mg, 51-119 mg) was not different from placebo (88 mg, 56-139 mg, P = .5). There were no changes in sputum eosinophils (mean ± SD) in a subgroup of 11 subjects (omega-3, 8.4% ± 8.2%; placebo, 7.8% ± 11.8%; P = .9). At the end of each treatment period, there were no differences in FEV1 % predicted (omega-3, 85% ± 13%; placebo, 84% ± 11%; P = .9) or ACQ score (omega-3, 1.1% ± 0.5%; placebo, 1.1% ± 0.5%; P = .9) (n = 23). Omega-3s caused significant lowering of blood triglyceride levels and expected shifts in serum fatty acids and eicosanoid metabolites, confirming adherence to the supplements; however, no changes were observed in urinary mast cell mediators. CONCLUSIONS: Three weeks of omega-3 supplements does not improve BHR to mannitol, decrease sputum eosinophil counts, or inhibit urinary excretion of mast cell mediators in people with mild to moderate asthma, indicating that dietary omega-3 supplementation is not useful in the short-term treatment of asthma. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00526357; URL: www.clinicaltrials.gov.

Effect of interferon-gamma on allergic airway responses in interferon-gamma-deficient mice.

Interferon (IFN)-gamma reduces airway responses after allergen challenge in mice. The mechanisms of this effect are not clear. These studies investigate whether IFN-gamma can reverse prolonged airway responses after allergen challenge in IFN-gamma-deficient (IFN-gammaKO) mice. Sensitized mice (IFN-gammaKO and wild-type [WT]) were challenged with ovalbumin. Airway responsiveness, eosinophils in bronchoalveolar lavage fluid, and lung lymphocyte subsets (CD4(+) and CD8(+)) were measured 24 hours and 8 weeks after challenge. In further experiments, we treated IFN-gammaKO mice with recombinant IFN-gamma starting 4 weeks after the challenge for 1 week or 4 weeks. Airway responsiveness, bronchoalveolar lavage eosinophils, and lung CD4(+) cells were increased 8 weeks after challenge in IFN-gammaKO but not WT mice. IFN-gamma treatment returned lung CD4(+) cell numbers to values obtained in unchallenged mice. One week of IFN-gamma treatment also returned airway responsiveness to baseline levels; however, 4-week treatment with IFN-gamma failed to decrease airway responsiveness below levels observed in untreated animals. This suggests that IFN-gamma plays an essential role in reversing allergen-induced airway inflammation and hyperresponsiveness and that it may have dual actions on the latter. Observations that IFN-gamma reverses airway responses, even when administered after challenge, suggests that IFN-gamma treatment could control allergic disease, including asthma.

Omalizumab and the immune system: an overview of preclinical and clinical data.

OBJECTIVE: This review discusses the role of immunoglobulin (Ig)E in allergic disease, inhibition of IgE with omalizumab, and the consequences of IgE inhibition (both clinically and in terms of the effect on the immune system). DATA SOURCES: Relevant publications obtained from a literature review. STUDY SELECTION: Relevant publications on IgE, allergic disease, and anti-IgE were critically evaluated. RESULTS: IgE plays a key role in allergic diseases such as allergic asthma and allergic rhinitis. Its role in healthy individuals is less well defined. Treatment of allergic asthma and rhinitis with omalizumab, a humanized monoclonal anti-IgE antibody, causes a marked reduction in circulating free IgE levels. This has been shown to reduce symptoms and decrease the need for other medication in patients with these allergic diseases. Anti-IgE treatment with omalizumab did not cause any of the complications that might, in theory, be expected to result from reduction in circulating free IgE, such as adverse effects upon the immune system or other body systems. CONCLUSIONS: The limited clinical data currently available suggest that this novel method of treatment for allergic asthma and rhinitis seems to be both effective and well tolerated in clinical use.