Epithelial-Associated Inflammatory Pathways Underlie Residual Asthma Exacerbations in Urban Children Treated with Mepolizumab Therapy

Rationale: Identification of airway inflammatory pathways in asthma has proven essential to understanding mechanisms of disease and has led to effective personalized treatment with biologic therapies. However, relatively little is known about patterns of airway inflammation at the time of respiratory illnesses and how such patterns relate to responsiveness to biologic therapies. Methods: The MUPPITS-1 (n=106) and MUPPITS-2 (n=290) studies investigated asthma exacerbations in urban children with exacerbation-prone asthma and ≥150/microliter blood eosinophils. Children in both studies received guidelines-based asthma care; in MUPPITS-2, participants were additionally randomized (1:1) to placebo or mepolizumab. Nasal lavage samples were collected during respiratory illnesses for RNA-sequencing and analyzed by modular analysis to assess genome-wide expression patterns associated with exacerbation illnesses. Results: Among 284 illnesses, exacerbations that occurred in the absence of mepolizumab therapy showed significantly higher upregulation of eosinophil associated inflammatory pathways (fold change values [FC]=1.27-1.43, p-values\u3c0.05), including a Type-2 inflammation module composed of eosinophil, mast cell, and IL-13 response genes. In contrast, exacerbations that occurred while on mepolizumab therapy showed significantly higher upregulation of several epithelial inflammatory pathways (FC=1.36-1.64, p-values\u3c0.05) including TGF-β/Smad3 signaling, extracellular matrix production, and epidermal growth factor receptor signaling. Conclusions: These results indicate that novel inflammatory pathways, likely originating from the airway epithelium and distinct from Type-2 or eosinophilic inflammation, drive residual exacerbations that occur in children treated with mepolizumab therapy added to guideline-based care. These findings identify likely mechanisms of persistent disease expression in these children despite significant depletion of eosinophils and can identify novel treatment targets for future studies

Mepolizumab Alters Regulation of Airway Type-2 Inflammation in Urban Children with Asthma by Disrupting Eosinophil Gene Expression but Enhancing Mast Cell and Epithelial Pathways

Rationale: Mepolizumab (anti-IL5) reduces asthma exacerbations in urban children. We previously utilized nasal transcriptomics to identify inflammatory pathways (gene co-expression modules) associated with exacerbations despite this therapy. To understand mepolizumab’s precise impact on these pathways, we assess gene co-expression and loss of correlation, “decoherence,” using differential co-expression network analyses. Methods: 290 urban children (6-17 years) with exacerbation-prone asthma and blood eosinophils ≥150/microliter were randomized (1:1) to q4 week placebo or mepolizumab injections added to guideline-based care for 52 weeks. Nasal lavage samples were collected before and during treatment for RNA-sequencing. Differential co-expression of gene networks was evaluated to assess interactions and regulatory aspects of type-2 and eosinophilic airway inflammation. Results: Mepolizumab, but not placebo, significantly reduced the overall expression of an established type-2 inflammation gene co-expression module (fold change=0.77, p=0.002) enriched for eosinophil, mast cell, and epithelial IL-13 response genes (242 genes). Mepolizumab uncoupled co-expression of genes in this pathway. During mepolizumab, but not placebo treatment, there was significant loss of correlation among eosinophil-specific genes including RNASE2 (EDN), RNASE3 (ECP), CLC, SIGLEC8, and IL5RA contrasting a reciprocal increase in correlation among mast cell-specific genes (TPSAB1, CPA3, FCER1A), T2 cytokines (IL4, IL5, and IL13), and POSTN. Conclusions: These results suggest mepolizumab disrupts the regulatory interactions of gene co-expression among airway eosinophils, mast cells and epithelium by interrupting transcription regulation in eosinophils with enhancement in mast cell and epithelial inflammation. This paradoxical effect may contribute to an incomplete reduction of asthma exacerbations and demonstrates how differential co-expression network analyses can identify targets for more precise therapies

Multi-omic association study identifies DNA methylation-mediated genotype and smoking exposure effects on lung function in children living in urban settings

Impaired lung function in early life is associated with the subsequent development of chronic respiratory disease. Most genetic associations with lung function have been identified in adults of European descent and therefore may not represent those most relevant to pediatric populations and populations of different ancestries. In this study, we performed genome-wide association analyses of lung function in a multiethnic cohort of children (n = 1,035) living in low-income urban neighborhoods. We identified one novel locus at the TDRD9 gene in chromosome 14q32.33 associated with percent predicted forced expiratory volume in one second (FEV1) (p = 2.4x10-9; βz = -0.31, 95% CI = -0.41- -0.21). Mendelian randomization and mediation analyses revealed that this genetic effect on FEV1 was partially mediated by DNA methylation levels at this locus in airway epithelial cells, which were also associated with environmental tobacco smoke exposure (p = 0.015). Promoter-enhancer interactions in airway epithelial cells revealed chromatin interaction loops between FEV1-associated variants in TDRD9 and the promoter region of the PPP1R13B gene, a stimulator of p53-mediated apoptosis. Expression of PPP1R13B in airway epithelial cells was significantly associated the FEV1 risk alleles (p = 1.3x10-5; β = 0.12, 95% CI = 0.06–0.17). These combined results highlight a potential novel mechanism for reduced lung function in urban youth resulting from both genetics and smoking exposure

The Effect of Subcutaneous German Cockroach Immunotherapy (SCIT) on Nasal Allergen Challenge (NAC) and Cockroach-specific Antibody Responses Among Urban Children and Adolescents

Rationale: Cockroach allergy contributes to asthma and rhinitis morbidity among many urban children. Treatment with cockroach SCIT could be beneficial. Methods: 8-17 year-old children with mild-moderate asthma from 11 urban sites participated in a randomized double-blind placebo-controlled SCIT trial using non-standardized, glycerinated German cockroach extract. Positive cockroach skin tests, cockroach-specific IgE, and nasal challenge response with total nasal symptom scores (TNSS) ≥6 or maximal sneeze scores of 3 during a graded NAC were required for enrollment. Following dose escalation, 0.4 ml of undiluted extract was targeted for maintenance dosing (∼7 mcg Bla g2/dose). The primary endpoint was change in NAC-induced mean TNSS from baseline to one year post randomization. Changes in cockroach-specific IgE (CRsIgE) and IgG4 (CRsIgG4) were also analyzed. Results: Mean TNSS did not significantly change from baseline in either group (placebo n=29, SCIT n=28). There was no significant difference in the change in mean TNSS between placebo and SCIT [−0.79±0.35 vs. −1.02±0.37, respectively, difference=0.2(−1.15, 0.70), p=0.63]. Baseline CRsIgE and CRsIgG4 didn’t differ between groups. Mean CRsIgE decreased in both groups following treatment: 3.6 to 2.3 kU/L (0.64 fold change), p=0.015 and 8.3 to 4.2 kU/L (0.51 fold change), p\u3c0.001 in placebo and SCIT respectively, but did not differ between groups [p=0.33]. Significant increases in CRsIgG4 post-treatment were observed among SCIT recipients only: 0.07 to 12.3 mg/L (176 fold change), p\u3c0.001. Conclusions: Cockroach SCIT increased CRsIgG4 levels but did not significantly alter NAC-induced TNSS responses. The extent to which NAC in these children may reflect clinical efficacy for rhinitis or asthma is uncertain

African-specific alleles modify risk for asthma at the 17q12-q21 locus in African Americans

BACKGROUND: Asthma is the most common chronic disease in children, occurring at higher frequencies and with more severe disease in children with African ancestry. METHODS: We tested for association with haplotypes at the most replicated and significant childhood-onset asthma locus at 17q12-q21 and asthma in European American and African American children. Following this, we used whole-genome sequencing data from 1060 African American and 100 European American individuals to identify novel variants on a high-risk African American-specific haplotype. We characterized these variants in silico using gene expression and ATAC-seq data from airway epithelial cells, functional annotations from ENCODE, and promoter capture (pc)Hi-C maps in airway epithelial cells. Candidate causal variants were then assessed for correlation with asthma-associated phenotypes in African American children and adults. RESULTS: Our studies revealed nine novel African-specific common variants, enriched on a high-risk asthma haplotype, which regulated the expression of GSDMA in airway epithelial cells and were associated with features of severe asthma. Using ENCODE annotations, ATAC-seq, and pcHi-C, we narrowed the associations to two candidate causal variants that are associated with features of T2 low severe asthma. CONCLUSIONS: Previously unknown genetic variation at the 17q12-21 childhood-onset asthma locus contributes to asthma severity in individuals with African ancestries. We suggest that many other population-specific variants that have not been discovered in GWAS contribute to the genetic risk for asthma and other common diseases

510 - Dupilumab is efficacious in patients with prurigo nodularis regardless of stable use of topical corticosteroids and topical calcineurin inhibitors: pooled results from two phase 3 trials (LIBERTY-PN PRIME and PRIME2)

Abstract Introduction Prurigo nodularis (PN) is a chronic inflammatory skin condition characterized by severely itchy skin nodules, which substantially affects quality of life. Although topical treatments are frequently prescribed, these therapies are limited by insufficient demonstrated evidence for efficacy, and/or associated side effects. Objectives This study reports the effect of dupilumab on pruritus, skin lesions, and quality of life in patients with PN, with or without stable use of topical corticosteroids (TCS) and/or topical calcineurin inhibitors (TCI), in an analysis of pooled data from two phase 3 trials. Materials & Methods LIBERTY-PN PRIME (NCT04183335) and PRIME2 (NCT04202679) were two randomized, double-blind, placebo-controlled, 24-week studies. Adults with PN inadequately controlled by topical prescription therapies, or for whom those therapies are inadvisable, were randomized 1:1 to dupilumab 300 mg every 2 weeks or matched placebo. “Stable use” was defined as maintaining the same medicine (low-to-medium potency TCS and/or TCI) during the study, with the same frequency of treatment (once or twice daily) as from 2 weeks prior to screening. Efficacy was assessed from baseline to Week 24 through the Worst Itch Numerical Rating Scale (WI-NRS; scored 0–10; high scores represent a poorer outcome), and the Investigator’s Global Assessment for PN-Stage score (IGA PN-S; scored 0–4; high scores represent a poorer outcome). Impact on Health-Related Quality of Life (HRQoL) was assessed through the Dermatology Life Quality Index questionnaire (DLQI; 10 questions scored 0–3 with a maximum score of 30; high scores represent poorer HRQoL). Results 311 patients were randomized (dupilumab/placebo n = 153/158), including 182 patients with stable use of TCI/TCS (dupilumab/placebo N = 91/91) and 129 patients without (dupilumab/placebo N = 62/67). Baseline demographics and disease characteristics were well balanced in both subgroups. At Week 24, significantly more patients treated with dupilumab with or without stable use of TCI/TCS achieved a ≥ 4-point improvement in WI-NRS (59.3%/58.1%) vs placebo (13.2%/26.9% [nominal P < 0.0001/P < 0.0001]). The proportion of patients achieving an IGA PN-S score of 0 or 1 at Week 24 was also significantly higher in the dupilumab group for patients with or without stable use of TCI/TCS (48.4%/43.5%), vs placebo (11.0%/25.4% [nominal P < 0.0001/P = 0.0319]). The positive impact of dupilumab treatment on HRQoL was greater, for patients with and without a stable use of TCI/TCS vs placebo, as suggested by the mean change from baseline in DLQI at Week 24 (−12.9/−11.9 vs −5.5/−7.1 [nominal P < 0.0001/P < 0.0001], respectively). Although the placebo response was higher for patients without stable use of TCI/TCS, the effect of dupilumab treatment was comparable in the two subgroups. Treatment-emergent adverse events (TEAEs) occurred with similar rates in dupilumab-treated patients with or without stable use of TCI/TCS (59.3%/60.7%), compared with placebo (53.3%/47.8%). Patients with or without stable use of TCI/TCS had similar rates of severe TEAEs in the dupilumab groups (2.2%/4.9%) and placebo groups (3.3%/4.5%). Conclusion Dupilumab treatment improves itch, skin lesions, and quality of life in patients with PN, with an acceptable safety profile, with little to no influence from concomitant treatment with topical therapies (TCI/TCS)