VX-445-Tezacaftor-Ivacaftor in Patients with Cystic Fibrosis and One or Two Phe508del Alleles.

BACKGROUND: VX-445 is a next-generation cystic fibrosis transmembrane conductance regulator (CFTR) corrector designed to restore Phe508del CFTR protein function in patients with cystic fibrosis when administered with tezacaftor and ivacaftor (VX-445-tezacaftor-ivacaftor). METHODS: We evaluated the effects of VX-445-tezacaftor-ivacaftor on Phe508del CFTR protein processing, trafficking, and chloride transport in human bronchial epithelial cells. On the basis of in vitro activity, a randomized, placebo-controlled, double-blind, dose-ranging, phase 2 trial was conducted to evaluate oral VX-445-tezacaftor-ivacaftor in patients heterozygous for the Phe508del CFTR mutation and a minimal-function mutation (Phe508del-MF) and in patients homozygous for the Phe508del CFTR mutation (Phe508del-Phe508del) after tezacaftor-ivacaftor run-in. Primary end points were safety and absolute change in percentage of predicted forced expiratory volume in 1 second (FEV1) from baseline. RESULTS: In vitro, VX-445-tezacaftor-ivacaftor significantly improved Phe508del CFTR protein processing, trafficking, and chloride transport to a greater extent than any two of these agents in dual combination. In patients with cystic fibrosis, VX-445-tezacaftor-ivacaftor had an acceptable safety and side-effect profile. Most adverse events were mild or moderate. The treatment also resulted in an increased percentage of predicted FEV1 of up to 13.8 points in the Phe508del-MF group (P<0.001). In patients in the Phe508del-Phe508del group, who were already receiving tezacaftor-ivacaftor, the addition of VX-445 resulted in an 11.0-point increase in the percentage of predicted FEV1 (P<0.001). In both groups, there was a decrease in sweat chloride concentrations and improvement in the respiratory domain score on the Cystic Fibrosis Questionnaire-Revised. CONCLUSIONS: The use of VX-445-tezacaftor-ivacaftor to target Phe508del CFTR protein resulted in increased CFTR function in vitro and translated to improvements in patients with cystic fibrosis with one or two Phe508del alleles. This approach has the potential to treat the underlying cause of cystic fibrosis in approximately 90% of patients. (Funded by Vertex Pharmaceuticals; VX16-445-001 ClinicalTrials.gov number, NCT03227471 ; and EudraCT number, 2017-000797-11 .).

Global patterns in the metacommunity structuring of lake macrophytes: regional variations and driving factors.

We studied community-environment relationships of lake macrophytes at two metacommunity scales using data from 16 regions across the world. More specifically, we examined (a) whether the lake macrophyte communities respond similar to key local environmental factors, major climate variables and lake spatial locations in each of the regions (i.e., within-region approach) and (b) how well can explained variability in the community-environment relationships across multiple lake macrophyte metacommunities be accounted for by elevation range, spatial extent, latitude, longitude, and age of the oldest lake within each metacommunity (i.e., across-region approach). In the within-region approach, we employed partial redundancy analyses together with variation partitioning to investigate the relative importance of local variables, climate variables, and spatial location on lake macrophytes among the study regions. In the across-region approach, we used adjusted R2 values of the variation partitioning to model the community-environment relationships across multiple metacommunities using linear regression and commonality analysis. We found that niche filtering related to local lake-level environmental conditions was the dominant force structuring macrophytes within metacommunities. However, our results also revealed that elevation range associated with climate (increasing temperature amplitude affecting macrophytes) and spatial location (likely due to dispersal limitation) was important for macrophytes based on the findings of the across-metacommunities analysis. These findings suggest that different determinants influence macrophyte metacommunities within different regions, thus showing context dependency. Moreover, our study emphasized that the use of a single metacommunity scale gives incomplete information on the environmental features explaining variation in macrophyte communities.

Average niche breadths of species in lake macrophyte communities respond to ecological gradients variably in four regions on two continents.

Different species' niche breadths in relation to ecological gradients are infrequently examined within the same study and, moreover, species niche breadths have rarely been averaged to account for variation in entire ecological communities. We investigated how average environmental niche breadths (climate, water quality and climate-water quality niches) in aquatic macrophyte communities are related to ecological gradients (latitude, longitude, altitude, species richness and lake area) among four distinct regions (Finland, Sweden and US states of Minnesota and Wisconsin) on two continents. We found that correlations between the three different measures of average niche breadths and ecological gradients varied considerably among the study regions, with average climate and average water quality niche breadth models often showing opposite trends. However, consistent patterns were also found, such as widening of average climate niche breadths and narrowing of average water quality niche breadths of aquatic macrophytes along increasing latitudinal and altitudinal gradients. This result suggests that macrophyte species are generalists in relation to temperature variations at higher latitudes and altitudes, whereas species in southern, lowland lakes are more specialised. In contrast, aquatic macrophytes growing in more southern nutrient-rich lakes were generalists in relation to water quality, while specialist species are adapted to low-productivity conditions and are found in highland lakes. Our results emphasise that species niche breadths should not be studied using only coarse-scale data of species distributions and corresponding environmental conditions, but that investigations on different kinds of niche breadths (e.g., climate vs. local niches) also require finer resolution data at broad spatial extents.

Real-world effectiveness of elexacaftor/tezacaftor/ivacaftor on the burden of illness in adolescents and adults with cystic fibrosis.

Background: Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) has been shown to be safe and efficacious in people with cystic fibrosis (CF) aged ≥2 years. Here, we describe results from an observational study assessing change in burden of illness following initiating ELX/TEZ/IVA in real-world settings. Methods: This US-based, multicenter, observational study used data from electronic medical records to evaluate real-world burden of illness before and after ELX/TEZ/IVA initiation in people with CF aged ≥12 years heterozygous for F508del and a minimal function mutation (F/MF) or an uncharacterized CFTR mutation. Endpoints included absolute change from baseline in percent predicted forced expiratory volume in 1 s (ppFEV1), body mass index (BMI) and BMI-for-age z-score, glycated hemoglobin (HbA1c), and numbers of pulmonary exacerbations (PEx). Results: Overall, 206 people with CF were enrolled (mean [SD] age 22.5 [11.1] years; 192 [93.2%] with F/MF genotype). Mean follow-up was 15.6 (SD, 1.6) months. Improvements in ppFEV1 (7.3 [95% CI: 5.7, 8.8] percentage points) were observed from baseline through follow-up. Increases in BMI (1.40 [95% CI: 1.07, 1.77] kg/m2) and BMI-for-age z-score (0.14 [95% CI: 0.00, 0.28]) were also observed from baseline at 12 months. The estimated annualized rate of any PEx was 1.31 at baseline and 0.61 over follow-up (rate ratio 0.47 [95% CI: 0.39, 0.55]), with annualized rates of PEx requiring antibiotics and hospitalizations of 0.55 and 0.88 in the baseline period and 0.12 and 0.36 over follow-up (rate ratios 0.22 [95% CI: 0.15, 0.31] and 0.41 [95% CI: 0.32, 0.51]), respectively. Absolute change in HbA1c was -0.22 (95% CI: -0.38, -0.06) from baseline through follow-up. Conclusions: ELX/TEZ/IVA treatment was associated with improved lung function, increased BMI, reduced frequency of PEx, and improved (i.e., reduced) HbA1c. These results confirm the broad clinical benefits of ELX/TEZ/IVA seen in clinical trials and show the potential for ELX/TEZ/IVA to improve markers of glucose metabolism.

Preliminary evidence for sustained efficacy of CFTR modulator therapy with concomitant rifabutin administration.

The concomitant use of elexacaftor/tezacaftor/ivacaftor (ETI) and strong CYP3A inducers including rifampin and rifabutin is not recommended due to the risk of drug-drug interactions (DDI). This presents a significant challenge to the treatment of non-tuberculous mycobacteria precluding the first line treatment. While rifabutin induces CYP3A activity, its effect appears to be moderate compared to rifampin. In this study, we investigated three cases in which concomitant use of rifabutin and CFTR modulators (ETI or ivacaftor monotherapy) was used, and these cases suggest that addition of rifabutin did not compromise the efficacy of ETI or ivacaftor as evidenced by pulmonary function and sweat chloride testing. A full physiologically based pharmacokinetic model predicted lung concentrations of ETI upon rifabutin coadministration to exceed the half-maximal effective concentrations (EC50) determined from chloride transport in phe508del human bronchial epithelial cells. This study provides preliminary evidence in support of the use of rifabutin in patients receiving ETI.

Global patterns and determinants of lake macrophyte taxonomic, functional and phylogenetic beta diversity.

Documenting the patterns of biological diversity on Earth has always been a central challenge in macroecology and biogeography. However, for the diverse group of freshwater plants, such research program is still in its infancy. Here, we examined global variation in taxonomic, functional and phylogenetic beta diversity patterns of lake macrophytes using regional data from six continents. A data set of ca. 480 lake macrophyte community observations, together with climatic, geographical and environmental variables, was compiled across 16 regions worldwide. We (a) built the very first phylogeny comprising most freshwater plant lineages; (b) exploited a wide array of functional traits that are important to macrophyte autoecology or that relate to lake ecosystem functioning; (c) assessed if different large-scale beta diversity patterns show a clear latitudinal gradient from the equator to the poles using null models; and (d) employed evolutionary and regression models to first identify the degree to which the studied functional traits show a phylogenetic signal, and then to estimate community-environment relationships at multiple spatial scales. Our results supported the notion that ecological niches evolved independently of phylogeny in macrophyte lineages worldwide. We also showed that taxonomic and phylogenetic beta diversity followed the typical global trend with higher diversity in the tropics. In addition, we were able to confirm that species, multi-trait and lineage compositions were first and foremost structured by climatic conditions at relatively broad spatial scales. Perhaps more importantly, we showed that large-scale processes along latitudinal and elevational gradients have left a strong footprint in the current diversity patterns and community-environment relationships in lake macrophytes. Overall, our results stress the need for an integrative approach to macroecology, biogeography and conservation biology, combining multiple diversity facets at different spatial scales.

Inhibition of Myeloperoxidase Activity in Cystic Fibrosis Sputum by Peptide Inhibitor of Complement C1 (PIC1).

Myeloperoxidase is the major peroxidase enzyme in neutrophil granules and implicated in contributing to inflammatory lung damage in cystic fibrosis. Free myeloperoxidase is present in cystic fibrosis lung fluid and generates hypochlorous acid. Here we report a new inhibitor of myeloperoxidase activity, Peptide Inhibitor of Complement C1 (PIC1). Using TMB as the oxidizing substrate, PIC1 inhibited myeloperoxidase activity in cystic fibrosis sputum soluble fractions by an average of a 3.4-fold decrease (P = 0.02). PIC1 also dose-dependently inhibited myeloperoxidase activity in a neutrophil lysate or purified myeloperoxidase by up to 28-fold (P < 0.001). PIC1 inhibited myeloperoxidase activity similarly, on a molar basis, as the specific myeloperoxidase inhibitor 4-Aminobenzoic acid hydrazide (ABAH) for various oxidizing substrates. PIC1 was able to protect the heme ring of myeloperoxidase from destruction by NaOCl, assayed by spectral analysis. PIC1 incubated with oxidized TMB reversed the oxidation state of TMB, as measured by absorbance at 450 nm, with a 20-fold reduction in oxidized TMB (P = 0.02). This result was consistent with an antioxidant mechanism for PIC1. In summary, PIC1 inhibits the peroxidase activity of myeloperoxidase in CF sputum likely via an antioxidant mechanism.

Complement effectors, C5a and C3a, in cystic fibrosis lung fluid correlate with disease severity.

In cystic fibrosis (CF), lung damage is mediated by a cycle of obstruction, infection, inflammation and tissue destruction. The complement system is a major mediator of inflammation for many diseases with the effectors C5a and C3a often playing important roles. We have previously shown in a small pilot study that CF sputum soluble fraction concentrations of C5a and C3a were associated with clinical measures of CF disease. Here we report a much larger study of 34 CF subjects providing 169 testable sputum samples allowing longitudinal evaluation comparing C5a and C3a with clinical markers. Levels of the strongly pro-inflammatory C5a correlated negatively with FEV1% predicted (P < 0.001), whereas the often anti-inflammatory C3a correlated positively with FEV1% predicted (P = 0.01). C5a concentrations correlated negatively with BMI percentile (P = 0.017), positively with worsening of an acute pulmonary exacerbation score (P = 0.007) and positively with P. aeruginosa growth in sputum (P = 0.002). C5a levels also correlated positively with concentrations of other sputum markers associated with worse CF lung disease including neutrophil elastase (P < 0.001), myeloperoxidase activity (P = 0.006) and DNA concentration (P < 0.001). In contrast to C5a, C3a levels correlated negatively with worse acute pulmonary exacerbation score and correlated negatively with sputum concentrations of neutrophil elastase, myeloperoxidase activity and DNA concentration. In summary, these data suggest that in CF sputum, increased C5a is associated with increased inflammation and poorer clinical measures, whereas increased C3a appears to be associated with less inflammation and improved clinical measures.

A 1-Year-Old with Mycobacterium tuberculosis Endocarditis with Mass Spectrometry Analysis of Cardiac Vegetation Composition.

In this study, we report the first case of Mycobacterium tuberculosis endocarditis in an immunocompetent child born in the United States. Mass spectrometry of the vegetation identified coagulation, humoral immune proteins, neutrophil granule proteins, and histones. Few neutrophils on histopathology suggest that neutrophil extracellular traps may contribute to tuberculous endocardiac mass formation.

Complement Effectors of Inflammation in Cystic Fibrosis Lung Fluid Correlate with Clinical Measures of Disease.

In cystic fibrosis (CF), lung damage is mediated by a cycle of obstruction, infection, and inflammation. Here we explored complement inflammatory effectors in CF lung fluid. In this study soluble fractions (sols) from sputum samples of 15 CF patients were assayed for complement effectors and analyzed with clinical measurements. The pro-inflammatory peptide C5a was increased 4.8-fold (P = 0.04) in CF sols compared with controls. Incubation of CF sols with P. aeruginosa or S. aureus increased C5a concentration 2.3-fold (P = 0.02). A peptide inhibitor of complement C1 (PIC1) completely blocked the increase in C5a concentration from P. aeruginosa in CF sol in vitro (P = 0.001). C5a concentration in CF sol correlated inversely with body mass index (BMI) percentile in children (r = -0.77, P = 0.04). C3a, which has anti-inflammatory effects, correlated positively with FEV1% predicted (rs = 0.63, P = 0.02). These results suggest that complement effectors may significantly impact inflammation in CF lung fluid.