FDA Public Workshop Summary-Addressing Challenges in Inhaled Antifungal Drug Development.

Allergic bronchopulmonary aspergillosis and invasive fungal diseases represent distinct infectious entities that cause significant morbidity and mortality. Currently, administered inhaled antifungal therapies are unapproved, have suboptimal efficacy, and are associated with considerable adverse reactions. The emergence of resistant pathogens is also a growing concern. Inhaled antifungal development programs are challenged by inadequate nonclinical infection models, highly heterogenous patient populations, low prevalence rates of fungal diseases, difficulties defining clinical trial enrollment criteria, and lack of robust clinical trial endpoints. On September 25, 2020, the US Food and Drug Administration (FDA) convened a workshop with experts in pulmonary medicine and infectious diseases from academia, industry, and other governmental agencies. Key discussion topics included regulatory incentives to facilitate development of inhaled antifungal drugs and combination inhalational devices, limitations of existing nonclinical models and clinical trial designs, patient perspectives, and industry insights.

Correction: Moss, R.B. Severe Fungal Asthma: A Role for Biologics and Inhaled Antifungals. J. Fungi 2023, 9, 85.

In the original publication [...].

Evaluation of Acebilustat, a Selective Inhibitor of Leukotriene B4 Biosynthesis, for Treatment of Outpatients With Mild-Moderate Coronavirus Disease 2019: A Randomized, Double-Blind, Placebo-Controlled Phase 2 Trial.

BACKGROUND: The vast majority of coronavirus disease 2019 (COVID-19) disease occurs in outpatients where treatment is limited to antivirals for high-risk subgroups. Acebilustat, a leukotriene B4 inhibitor, has potential to reduce inflammation and symptom duration. METHODS: In a single-center trial spanning Delta and Omicron variants, outpatients were randomized to 100 mg/d of oral acebilustat or placebo for 28 days. Patients reported daily symptoms via electronic query through day 28 with phone follow-up on day 120 and collected nasal swab samples on days 1-10. The primary outcome was sustained symptom resolution to day 28. Secondary 28-day outcomes included time to first symptom resolution, area under the curve (AUC) for longitudinal daily symptom scores, duration of viral shedding through day 10, and symptoms on day 120. RESULTS: Sixty participants were randomized to each study arm. At enrollment, the median duration was 4 days (interquartile range, 3-5 days), and the median number of symptoms was 9 (7-11). Most patients (90%) were vaccinated, with 73% having neutralizing antibodies. A minority of participants (44%; 35% in the acebilustat arm and 53% in placebo) had sustained symptom resolution at day 28 (hazard ratio, 0.6 [95% confidence interval, .34-1.04]; P = .07 favoring placebo). There was no difference in the mean AUC for symptom scores over 28 days (difference in mean AUC, 9.4 [95% confidence interval, -42.1 to 60.9]; P = .72). Acebilustat did not affect viral shedding or symptoms at day 120. CONCLUSIONS: Sustained symptoms through day 28 were common in this low-risk population. Despite this, leukotriene B4 antagonism with acebilustat did not shorten symptom duration in outpatients with COVID-19. Clinical Trials Registration. NCT04662060.

Severe Fungal Asthma: A Role for Biologics and Inhaled Antifungals.

Allergic asthma has traditionally been treated with inhaled and systemic glucocorticosteroids. A continuum of allergic fungal airways disease associated with Aspergillus fumigatus colonization and/or atopic immune responses that encompasses fungal asthma, severe asthma with fungal sensitization and allergic bronchopulmonary aspergillosis is now recognized along a phenotypic severity spectrum of T2-high immune deviation lung disease. Oral triazoles have shown clinical, anti-inflammatory and microbiologic efficacy in this setting; in the future inhaled antifungals may improve the therapeutic index. Humanized monoclonal antibody biologic agents targeting T2-high disease also show efficacy and promise of improved control in difficult cases. Developments in these areas are highlighted in this overview.

Rate of Lung Function Decline in People with Cystic Fibrosis Having a Residual Function Gene Mutation.

INTRODUCTION: Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Approximately 5% of people with CF have residual function (RF) CFTR mutations that result in partially retained CFTR activity. Published literature on disease trajectory among those with RF mutations is limited. In this retrospective study, we characterized lung function decline across different age groups in CFTR modulator-untreated people with CF heterozygous for F508del and an RF mutation (F/RF). METHODS: Rate of decline in percent predicted forced expiratory volume in 1 s (ppFEV1) was analyzed using data from the US CF Foundation Patient Registry (2006-2014) in F/RF (all), F/RF (excluding R117H), and F508del homozygous (F/F) cohorts. Annual rates of ppFEV1 decline were estimated over 2-year periods based on calendar year. Subgroup analyses by age [6-12 (children), 13-17 (adolescents), 18-24 (young adults), and ≥ 25 years (adults)] were performed. RESULTS: The estimated annualized rate of ppFEV1 decline was - 0.70 percentage points per year (95% CI -1.09, -0.30) in the F/RF (all) cohort (N = 1242) versus -1.91 percentage points per year (95% CI -2.01, -1.80) in the F/F cohort (N = 11,916) [difference, 1.29 percentage points per year (95% CI 0.88, 1.70); P < 0.001]. In the F/RF (all) cohort, all age groups demonstrated lung function decline ranging from -0.30 to -1.38. In the F/RF (excluding R117H) cohort, the rate of decline was -1.05 percentage points per year (95% CI -1.51, -0.60) [difference versus F/F cohort, 0.95 percentage points per year (95% CI 0.48, 1.41; P < 0.001); not statistically significant in children and young adults]. CONCLUSION: Progressive lung function decline was observed in people with F/RF genotypes across all assessed age groups, reinforcing the importance of early intervention and clinical monitoring to preserve lung function in all people with CF.

In people with cystic fibrosis, lung function typically decreases over time and is linked to the severity of the disease. How fast lung function decreases (referred to as the rate of lung function decline) in cystic fibrosis depends on the specific mutations (changes) in the CFTR gene (which causes the disease). Lung function decline has been well studied in some mutation groups, but not many previous studies have looked at lung function decline in people with one copy of the F508del-CFTR mutation (which is the most common CFTR mutation and results in little to no functional CFTR protein) and another CFTR mutation called a residual function mutation (referred to as people with F/RF genotypes). We used data from the US Cystic Fibrosis Foundation Patient Registry (which collects information on the health of people in the USA who have cystic fibrosis), to look at the rate of lung function decline in people with F/RF genotypes. We found that people with cystic fibrosis who have F/RF genotypes experience lung function loss over time. We also found that this lung function loss occurred in people of all ages with F/RF genotypes. This finding supports the importance of early treatment to help prevent lung function loss in all people with cystic fibrosis, including people with F/RF genotypes.

Clinician variability in the diagnosis and treatment of aspergillus fumigatus-related conditions in cystic fibrosis: An international survey.

BACKGROUND: The diagnosis and treatment of Aspergillus fumigatus (Af)-related conditions remain a challenge in cystic fibrosis (CF) due to overlapping features of disease and absence of clinical guidelines for Af-related conditions outside of ABPA. OBJECTIVE: To investigate the differences of clinical practice in the diagnosis and management of Af-related conditions in CF. METHODS: We conducted an international survey to CF clinicians to ascertain the screening, diagnostic, and treatment practices for Af-related conditions in CF. Respondents were grouped into geographical regions and regional comparisons using chi-square tests of independence or Fisher's tests were performed. RESULTS: A total of 319 survey responses from 35 countries were analyzed. We observed differences in use and frequency of fungus culture, Aspergillus-specific IgE and IgG, skin prick testing, and pulmonary function testing as screening for Af-related conditions between the geographical regions. ABPA and Aspergillus bronchitis diagnostic criteria selection differed by region; significantly greater proportion of United States (US) and Canadian clinicians were unable to define Aspergillus bronchitis compared to Europe and other regions. Decision to treat ABPA was uniform across regions, but the consideration of Aspergillus bronchitis as a clinical disease warranting therapy differed between regions. The use of glucocorticoid and itraconazole was the first-line treatment of ABPA among clinicians; however, prednisone monotherapy was more common in US and Canada. CONCLUSIONS: Significant variability in the diagnosis and management of Aspergillus-related conditions in CF was observed. Future studies are necessary to better harmonize the approach to Af-related disease in CF.

Biomarkers for the Diagnosis of Allergic Bronchopulmonary Aspergillosis in Cystic Fibrosis: A Systematic Review and Meta-Analysis.

BACKGROUND: Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity reaction to Aspergillus fumigatus and impacts 10% of individuals with cystic fibrosis (CF). A diagnosis of ABPA is challenging to establish in CF owing to overlapping clinical and radiologic features with CF lung disease. Recent studies have identified blood tests, imaging, and other biomarkers that may be useful for diagnosis. OBJECTIVE: To summarize biomarkers that can aid in the diagnosis of ABPA in CF patients and to quantify their diagnostic accuracy through meta-analysis. METHODS: We searched MEDLINE, EMBASE, and the Cochrane Controlled Register of Trials and included studies that used a laboratory technique or imaging modality in CF patients diagnosed with ABPA. Pooled sensitivity and specificity were calculated using a hierarchical summary receiver operating characteristic model. RESULTS: We identified 791 articles, of which 29 met our eligibility criteria and 9 were included in the meta-analysis. Hyperattenuating mucus on computed tomography (CT) scan (n = 3 studies; pooled sensitivity 62% and specificity 92%) and serum specific immunoglobulin E against recombinant Aspergillus funigatus antigens f4 (n = 6; 69%, 89%) and f6 (n = 6; 39%, 97%) demonstrated high specificity. Based on single studies, serum thymus and activation regulated chemokine (92%, 94%), stimulated basophil expression of CD203c (94%, 74%), the inverted mucoid impaction signal on magnetic resonance imaging (94%, 100%), and skin prick test with recombinant Aspergillus fumigatus f4 and/or f6 (100%, 100%) showed high sensitivity and specificity. CONCLUSIONS: Recent studies have found promising biomarkers for diagnosing ABPA in CF. Further research is needed to improve our understanding of their utility in diagnosis and disease monitoring.

Long-Term Ivacaftor in People Aged 6 Years and Older with Cystic Fibrosis with Ivacaftor-Responsive Mutations.

INTRODUCTION: Mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) affect the quantity and/or function of CFTR protein reaching the cell surface. Ivacaftor, a CFTR potentiator that enhances chloride transport, increases the channel-open probability of normal and dysfunctional CFTR. Initially approved for people with CF (pwCF) with G551D-CFTR gating mutations, ivacaftor demonstrated clinical benefit in pwCF with other gating mutations and certain residual function mutations, including R117H-CFTR, in clinical studies. We evaluated the long-term safety and efficacy of ivacaftor in pwCF aged 6 years and older with non-G551D-CFTR ivacaftor-responsive mutations. METHODS: Efficacy and safety data from a phase 3, multicenter, open-label, extension study for participants from Study 110 (R117H-CFTR mutations), Study 111 (non-G551D-CFTR gating mutations), and Study 113 (n-of-1 pilot study in participants with residual CFTR function) were analyzed. Following washout from the randomized parent study, participants received oral ivacaftor 150 mg once every 12 h for 104 weeks. RESULTS: Forty-one of 121 participants completed treatment through 104 weeks; 59 participants who did not complete the extension study continued treatment with commercial ivacaftor. The most common adverse events were pulmonary exacerbation (46.3%) and cough (33.9%). Most treatment-emergent adverse events were mild/moderate in severity and consistent with manifestations of CF or the ivacaftor safety profile. Rapid, durable improvement occurred across all efficacy endpoints. CONCLUSIONS: Ivacaftor was generally safe and well tolerated with no new safety concerns for up to 104 weeks in pwCF with ivacaftor-responsive mutations. The pattern of improvement across efficacy endpoints was durable and generally consistent with parent-study outcomes. TRIAL REGISTRATION: NCT01707290.

Manifestations of pulmonary aspergillosis in pediatrics.

PURPOSE OF REVIEW: Aspergillus spp. cause a clinical spectrum of disease with severity of disease dependent on degree of immune compromise, nature and intensity of inflammatory host response, and/or underlying lung disease. Chronic pulmonary aspergillosis encompasses a spectrum of diseases including aspergilloma, Aspergillus nodules, chronic cavitary pulmonary aspergillosis, chronic fibrosing pulmonary aspergillosis, and subacute invasive pulmonary aspergillosis. Allergic bronchopulmonary aspergillosis (ABPA) paradoxically is an immune hypersensitivity manifestation in the lungs that almost always occurs in the setting of underlying asthma or cystic fibrosis. These chronic Aspergillus conditions are now becoming more prevalent than invasive Aspergillus, thus it is important to be aware of the current literature of these conditions. RECENT FINDINGS: High-level research assessing the clinical significance and treatment options of these chronic diseases are lacking. Recent literature suggests colonization is antecedent for local airway infection (Aspergillus bronchitis), chronic or allergic bronchopulmonary disease, or invasive and potentially disseminated disease. There have been few advances in assessment of treatment of ABPA. SUMMARY: Research assessing the clinical significance and treatment options is currently needed.

Mucus plugging, air trapping, and bronchiectasis are important outcome measures in assessing progressive childhood cystic fibrosis lung disease.

OBJECTIVE: To determine which outcome measures could detect early progression of disease in school-age children with mild cystic fibrosis (CF) lung disease over a two-year time interval utilizing chest computed tomography (CT) scores, quantitative CT air trapping (QAT), and spirometric measurements. METHODS: Thirty-six school-age children with mild CF lung disease (median [interquartile range] age 12 [3.7] years; percent predicted forced expiratory volume in 1 second (ppFEV1 ) 99 [12.5]) were evaluated by serial spirometer-controlled chest CT scans and spirometry at baseline, 3-month, 1- and 2-years. RESULTS: No significant changes were noted at 3-month for any variable except for decreased ppFEV1 . Mucus plugging score (MPS) and QATA1andA2 increased at 1- and 2-years. The bronchiectasis score (BS), and total score (TS) were increased at 2-year. All variables tested with the exception of bronchial wall thickness score, parenchymal score (PS), and ppFEV1 , were consistent with longitudinal worsening of lung disease. Multivariate analysis revealed baseline PS, baseline TS, and 1-year changes in BS and air trapping score were predictive of 2-year changes in BS. CONCLUSIONS: MPS and QATA1-A2 were the most sensitive indicators of progressive childhood CF lung disease. The 1-year change in the bronchiectasis score had the most positive predictive power for 2-year change in bronchiectasis.

Resistin is elevated in cystic fibrosis sputum and correlates negatively with lung function.

BACKGROUND: Resistin is an immunometabolic mediator that is elevated in several inflammatory disorders. A ligand for Toll-like receptor 4, resistin modulates the recruitment and activation of myeloid cells, notably neutrophils. Neutrophils are major drivers of cystic fibrosis (CF) lung disease, in part due to the release of human neutrophil elastase- and myeloperoxidase-rich primary granules, leading to tissue damage. Here we assessed the relationship of resistin to CF lung disease. METHODS: Resistin levels were measured in plasma and sputum from three retrospective CF cohorts spanning a wide range of disease. We also assessed the ability of neutrophils to secrete resistin upon activation in vitro. Finally, we constructed a multivariate model assessing the relationship between resistin levels and lung function. RESULTS: Plasma resistin levels were only marginally higher in CF than in healthy control subjects. By contrast, sputum resistin levels were very high in CF, reaching 50-100 fold higher levels than in plasma. Among CF patients, higher plasma resistin levels were associated with allergic bronchopulmonary aspergillosis, and higher sputum resistin levels were associated with CF-related diabetes. Mechanistically, in vitro release of neutrophil primary granules was concomitant with resistin secretion. Overall, sputum resistin levels were negatively correlated with CF lung function, independently of other variables (age, sex, and genotype). CONCLUSIONS: Our data establish relationships between resistin levels in the plasma and sputum of CF patients that correlate with disease status, and identify resistin as a novel mechanistic link between neutrophilic inflammation and lung disease in CF.

Sweat rate analysis of ivacaftor potentiation of CFTR in non-CF adults.

To determine if ivacaftor (Kalydeco) influences non-CF human CFTR function in vivo, we measured CFTR-dependent (C-sweat) and CFTR-independent (M-sweat) rates from multiple identified sweat glands in 8 non-CF adults. The two types of sweating were stimulated sequentially with intradermal injections of appropriate reagents; each gland served as its own control via alternating off-on drug tests on both arms, given at weekly intervals with 3 off and 3 on tests per subject. We compared drug effects on C-sweating stimulated by either high or low concentrations of ß-adrenergic cocktail, and on methacholine-stimulated M-sweating. For each subject we measured ~700 sweat volumes from ~75 glands per arm (maximum 12 readings per gland), and sweat volumes were log-transformed for statistical analysis. T-tests derived from linear mixed models (LMMs) were more conservative than the familiar paired sample t-tests, and show that ivacaftor significantly increased C-sweating stimulated by both levels of agonist, with a larger effect in the low cocktail condition; ivacaftor did not increase M-sweat. Concurrent sweat chloride tests detected no effect of ivacaftor. We conclude that ivacaftor in vivo increases the open channel probability (PO) of WT CFTR, provided it is not already maximally stimulated.

The myriad challenges of respiratory fungal infection in cystic fibrosis.

Fungal infection in cystic fibrosis (CF) is a recognized challenge, with many areas requiring further investigation. Consensus definitions exist for allergic bronchopulmonary aspergillus in CF, but the full scope of clinically relevant non-allergic fungal disease in CF-asymptomatic colonization, transient or chronic infection localized to endobronchial mucus plugs or airway tissue, and invasive disease-is yet to be clearly defined. Recent advances in mycological culture and non-culture identification have expanded the list of both potential pathogens and community commensals in the lower respiratory tract. Here we aim to outline the current understanding of fungal presence in the CF respiratory tract, risk factors for acquiring fungi, host-pathogen interactions that influence the role of fungi from bystander to pathogen, advances in the diagnostic approaches to isolating and identifying fungi in CF respiratory samples, challenges of classifying clinical phenotypes of CF patients with fungi, and current treatment approaches. Development and validation of biomarkers characteristic of different fungal clinical phenotypes, and controlled trials of antifungal agents in well-characterized target populations, remain central challenges to surmount and goals to be achieved.

Cystic fibrosis transmembrane conductance regulator modulators: precision medicine in cystic fibrosis.

PURPOSE OF REVIEW: The aim of this study was to describe the newest development in cystic fibrosis (CF) care, CF transmembrane conductance regulator (CFTR) modulator therapies. RECENT FINDINGS: Phase II results showing CFTR modulator triple therapies are more effective than current CFTR modulators. SUMMARY: CFTR modulator therapy targets the protein defective in CF and boosts its function, but the drug must match mutation pathobiology. Ivacaftor, a CFTR potentiator, was the first modulator approved in 2012, with impressive improvement in lung function and other measures of disease in patients with gating and other residual function mutations (∼10% of CF patients). In 2015, the combination of lumacaftor, a CFTR corrector, and ivacaftor was approved for patients homozygous for the F508del mutation (∼40-50% of the CF population) with positive but less impressive clinical response and 10-20% incidence of intolerance. A next-generation CFTR corrector, tezacaftor, with ivacaftor equally effective and better tolerated than lumacaftor, has also received US Food and Drug Administration approval. Novel CFTR correctors, entering Phase 3 trials in triple modulator combination with tezacaftor-ivacaftor, appear substantially more effective for patients who are homozygous for the F508del mutation and can provide benefit for patients with a single F508del mutation. This offers promise of effective CFTR modulator therapy for nearly 90% of CF patients.

Lung function decline is delayed but not decreased in patients with cystic fibrosis and the R117H gene mutation.

BACKGROUND: Patients with cystic fibrosis (CF) experience variable lung disease phenotypes. The R117H mutation is often associated with preserved lung function. Our objective was to compare the rate of lung function decline in patients with the R117H mutation and patients homozygous for the F508del mutation. METHODS: Rate of decline in percentage-of-predicted FEV1 (ppFEV1) was analyzed using the 2006-2010 US CF Foundation Patient Registry. RESULTS: 4-year rate of decline was slower in 156 R117H patients compared with 6251 F508del patients (-0.61 vs -2.03 ppFEV1/year, P<0.001). Rates of decline in children were slower in R117H vs F508del patients (6-12-year-olds: +0.73 vs -1.91 ppFEV1/year, P<0.001 and 13-17-year-olds: -1.55 vs -2.66 ppFEV1/year, P=0.046), whereas rates in adults were not significantly different (18-24-year-olds: -1.52 vs -2.12, P=0.26 and ≥25-year-olds: -1.17 vs -1.40, P=0.33). CONCLUSIONS: These findings are consistent with a delayed onset, but ultimately similar progression, of lung disease in R117H compared with homozygous F508del patients.

Small Colony Variants of Pseudomonas aeruginosa Display Heterogeneity in Inhibiting Aspergillus fumigatus Biofilm.

Pseudomonas aeruginosa and Aspergillus fumigatus are major microbes in cystic fibrosis (CF). We reported non-mucoid P. aeruginosa isolates more inhibitory to A. fumigatus than mucoid ones. Another CF P. aeruginosa phenotype, small colony variants (SCVs), is an unknown factor in intermicrobial competition with A. fumigatus. Clinical SCV isolates and reference CF non-mucoid isolate (Pa10, producing normal-sized colonies) were compared. Live cells of P. aeruginosa or filtrates from P. aeruginosa planktonic or biofilm cultures were co-incubated with A. fumigatus growing under conditions allowing biofilm formation or with preformed biofilm. Metabolic activity of A. fumigatus biofilm was then measured. When necessary, assays were done after adjustment for growth differences by adding fresh medium to the planktonic culture filtrate. Pyoverdine determinations were performed spectrophotometrically on the planktonic culture filtrates. In all experimental conditions (live cells and planktonic or biofilm culture filtrates of P. aeruginosa versus A. fumigatus biofilm formation or preformed biofilm), three SCV isolates were less inhibitory than Pa10, two equal or more inhibitory. Adjusting planktonic culture filtrates for growth differences showed SCV inhibition differences variably related to growth or deficient inhibitor production. Studies suggested the principal P. aeruginosa inhibitor to be pyoverdine. SCV isolates appear heterogeneous in their capacity to inhibit A. fumigatus biofilm. SCV isolates can be important in the CF microbiome, because they are capable of intermicrobial inhibition.