Aerosol Biologics for the Treatment of Eosinophilic Asthma

Asthma is a heterogeneous chronic airway disease comprising of distinct phenotypes characterized by different immunopathophysiologic pathways, clinical features, disease severity, and response to treatment. The phenotypes of asthma include eosinophilic, neutrophilic, mixed cellularity, and paucigranulocytic asthma. Eosinophilic asthma is principally a T helper type 2 (Th2)-mediated airway disease. However, several other immune and structural cells secrete the cytokines implicated in the pathogenesis of eosinophilic asthma. Innate type 2 lymphoid cells, mast cells, basophils, and eosinophils secrete Th2 cytokines, such as interleukin-4 (IL-4), IL-13, and IL-5. Additionally, airway epithelial cells produce alarmin cytokines, including IL-25, IL-33, and thymic stromal lymphopoietin (TSLP). Alarmins are the key initiators of allergic inflammation at the sentinel mucosal surfaces. Innovative biotherapeutic research has led to the discovery of monoclonal antibodies which target and inhibit the immunopathological effects of the cytokines involved in the pathogenesis of eosinophilic asthma. Parenteral biologics targeting the inciting interleukins, include mepolizumab and reslizumab (anti-IL-5), benralizumab (anti-IL-5Rα), dupilumab (anti-4Rα), and tezelizumab (anti-TSLP). They have been shown to significantly reduce annualized exacerbation rates, improve asthma control, lung function, and quality of life. Currently, there are no pulmonary delivered aerosol biologics for topical treatment of asthma. CSJ117 is a potent neutralizing antibody Fab fragment against TSLP, formulated as a PulmoSol TM engineered powder, and is delivered to the lungs by a dry powder inhaler. Phase 2 placebo-controlled clinical trial evaluated the efficacy and safety of CSJ117. CSJ117 delivered as an inhaler attenuated the late asthmatic response (LAR), and the early asthmatic response (EAR) after allergen inhalation challenge (AIC) at day 84 of treatment. The maximum decrease in FVE1 from pre-AIC were significantly lower in the CSJ117 group compared to placebo (P = 029), during LAR. CSJ117 also significantly reduced fractional exhaled nitric oxide before AIC at day 83; and significantly reduced the allergen-induced increase in % sputum eosinophil count. Pulmonary delivery of biologics directly to the airway mucosal surface has several advantages over parenteral routes, particularly in treating airway diseases such as asthma. Inhaler delivered biologics, such as CSJ117 are innovative and attractive methods of future precision treatment of asthma, and other respiratory diseases.

Human and Mouse Eosinophils Differ in Their Ability to Biosynthesize Eicosanoids, Docosanoids, the Endocannabinoid 2-Arachidonoyl-glycerol and Its Congeners

High eosinophil (EOS) counts are a key feature of eosinophilic asthma. EOS notably affect asthmatic response by generating several lipid mediators. Mice have been utilized in hopes of defining new pharmacological targets to treat asthma. However, many pinpointed targets in mice did not translate into clinics, underscoring that key differences exist between the two species. In this study, we compared the ability of human (h) and mouse (m) EOS to biosynthesize key bioactive lipids derived from arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). hEOS were isolated from the blood of healthy subjects and mild asthmatics, while mEOSs were differentiated from the bone marrow. EOSs were treated with fatty acids and lipid mediator biosynthesis assessed by LC-MS/MS. We found that hEOS biosynthesized leukotriene (LT) C4 and LTB4 in a 5:1 ratio while mEOS almost exclusively biosynthesized LTB4. The biosynthesis of the 15-lipoxygenase (LO) metabolites 15-HETE and 12-HETE also differed, with a 15-HETE:12-HETE ratio of 6.3 for hEOS and 0.727 for mEOS. EOS biosynthesized some specialized pro-resolving mediators, and the levels from mEOS were 9-times higher than those of hEOS. In contrast, hEOS produced important amounts of the endocannabinoid 2-arachidonoyl-glycerol (2-AG) and its congeners from EPA and DHA, a biosynthetic pathway that was up to ~100-fold less prominent in mEOS. Our data show that hEOS and mEOS biosynthesize the same lipid mediators but in different amounts. Compared to asthmatics, mouse models likely have an amplified involvement of LTB4 and specialized pro-resolving mediators and a diminished impact of the endocannabinoid 2-arachidonoyl-glycerol and its congeners.

Intranasal GSK2245035, a Toll-like receptor 7 agonist, does not attenuate the allergen-induced asthmatic response in a randomized, double-blind, placebo-controlled experimental medicine study

Background Allergic asthma is a heterogenous disorder predominantly driven by a type 2 inflammatory response to aeroallergens. Therapeutic modulation to rebalance these type 2 responses may offer clinical benefit for allergic respiratory inflammatory diseases, with the potential for disease modification. GSK2245035, a selective toll-like receptor-7 agonist, preferentially stimulates the induction of type 1 interferon alpha, reducing type 2 responses. Objective This study investigated whether intranasal GSK2245035 reduced allergen-induced bronchial reactivity in mild allergic asthma. Methods This double-blind, placebo-controlled, parallel-group Phase IIa trial randomized (1:1) participants with mild allergic asthma to intranasal GSK2245035 20 ng or placebo once weekly for 8 weeks; follow-up was conducted 1, 4, and 12 weeks after treatment. Allergen-induced late asthmatic response 1 week after treatment was measured as minimum and weighted mean forced expiratory volume in 1 second (FEV1) 4–10 hours following bronchial allergen challenge (primary endpoint). Pharmacodynamic and allergic biomarkers, and adverse events, were assessed. A Bayesian analysis framework was used; a posterior probability >0.7 denoted primary endpoint success. Results Thirty-six participants were randomized (GSK2245035, n = 22; placebo, n = 14). The percentage attenuation in late asthmatic response was –4.6% (posterior probability: 0.385) and –10.5% (posterior probability: 0.303) for minimum and weighted mean FEV1, respectively. Type 2 responses were confirmed by changes in lung function, eosinophils (blood and sputum), interleukin-5 (sputum) and fractional exhaled nitric oxide biomarkers pre- and post-bronchial allergen challenge. However, no treatment effect was observed. Adverse events were reported by 10/14 (71%) and 21/22 (95%) participants in the placebo and GSK2245035 groups, respectively; headache was the most common. Conclusions and clinical relevance Although target engagement was observed, weekly intranasal GSK2245035 20 ng for 8 weeks did not substantially attenuate the late asthmatic response in participants with mild allergic asthma. Overall, treatment was well tolerated.

The impact of maternal periodontitis in the development of asthma in the offspring

Clinical and experimental studies show an association between maternal periodontitis and adverse outcomes during gestation. On the other hand, there were no studies evaluating the impact of maternal periodontitis on the offspring. Thus, our objective was to investigate the repercussion of maternal periodontitis on the development of asthma in the offspring. Pregnant rats were submitted or not to periodontitis by ligature technique. Thirty days after birth, the puppies were sensitized and challenged with ovalbumin (OVA) in order to induce asthmatic response. Our results showed that maternal periodontitis reduced cellular infiltrate in the parenchyma of offspring, tracheal responsiveness, lung edema, and anti-OVA antibodies, without alter mucus as well as cytokines production. We concluded that periodontitis has relevant impact on the offspring’s immune system, blunting the response to allergic and inflammatory stimulus. This study shows the important role of oral health during pregnancy and opens possibilities for future studies in order to explain the effects of periodontitis during pregnancy in the offspring.

Use of a vibrating mesh nebulizer for allergen challenge

Background Allergen inhalation tests are a valuable research tool. The allergen dose producing an early asthmatic response (EAR) can be predicted from methacholine responsiveness and allergen skin test endpoint (STE). The Wright® jet nebulizer, which is both inefficient and increasingly difficult to obtain, has been used historically. We assessed the Solo® vibrating mesh nebulizer as an alternative for allergen and methacholine challenges. Methods Eighteen mild atopic asthmatics completed the study. Doubling concentration allergen prick skin tests were performed to determine the STE in allergen units/mL. The Wright® protocol was used to measure the methacholine provocation dose causing a 20% forced expired volume in one second (FEV1) fall (PD20) (μg) and the allergen PD20 (units). The Solo® protocol (0.5 mL nebulized to completion, tidal breathing inhalation) was used to determine both methacholine PD20 and allergen PD20. The nebulizer order was randomized and separated by ≥ 2 weeks. Results All data were log transformed. The allergen PD20, predicted from the methacholine PD20 and the STE, was within 2 doubling doses of the PD20 measured with the Wright® and 2.64 doubling doses of that measured with Solo®. The Wright® allergen PD20 correlated with the Wright® methacholine PD20 (r = 0.74) and the STE (r = 0.78) and more strongly with the product of the two (Wright® methacholine PD20 × STE, r = 0.91, p < 0.00001). The Solo® allergen PD20 showed similar relationships with the Solo® methacholine PD20 (r = 0.61), the STE (r = 0.75) and the product of the two (Solo® methacholine PD20 × STE, r = 0.83, p < 0.00002). The Wright® and the Solo® methacholine geometric mean PD20s were not significantly different (49.3 and 54.5 μg respectively, p = 0.62). The Wright® allergen PD20 was slightly but significantly lower than the Solo® allergen PD20 (geometric means 6.7 and 10.5 units respectively, p = 0.003). Conclusion The Solo® allergen PD20 showed the same relationship with methacholine responsiveness and STE as did the Wright®. The Solo® allergen PD20 was slightly but significantly higher than the Wright® allergen PD20. The Solo® vibrating mesh nebulizer was well tolerated and is an acceptable alternative for allergen challenge. Trial registration clinicaltrials.gov: NCT03491358