Cystic fibrosis

Population Pharmacokinetics of Elexacaftor, Tezacaftor and Ivacaftor in a Real-World Cohort of Adults with Cystic Fibrosis

BACKGROUND AND OBJECTIVES

Elexacaftor-tezacaftor-ivacaftor (ETI), a combination of cystic fibrosis transmembrane conductance regulator (CFTR) modulators, has become the therapeutic standard of care for most people with cystic fibrosis (pwCF). People with cystic fibrosis exhibit differences in CFTR genotypes and have important differences in phenotypic characteristics including age, body weight, pancreatic status, disease severity, and comorbidities. While these differences predict large interindividual variability (IIV) in ETI exposure, there is a unique dose regimen recommended for adults. This raises questions around the "one-dose fits all" strategy.

OBJECTIVES

The aims of this study were to describe real-world population pharmacokinetics (Pop-PK) of ETI in adults with CF and identify factors associated with IIV.

METHOD

As part of the ongoing French national observational cohort study the Pop-PK analysis included 552 plasma concentrations drawn routinely from 325 adults with CF.

RESULTS

A one-compartment model with first order absorption and elimination best represented all three compounds, and an additional lag-time for elexacaftor PK data. Large IIV was observed in ETI, with an area under the curve (AUC0-24h for elexacaftor and tezacaftor, and AUC0-12h for ivacaftor) ranging respectively, from 58.7-422.9 mg⋅h/L; 38.0-207.7 mg⋅h/L and 4.9-64.9 mg⋅h/L. The main sources of IIV identified in the final ETI Pop-PK models were body weight, age, exocrine pancreatic insufficiency and CFTR genotype.

CONCLUSION

This study established the first ETI Pop-PK analysis in adults with CF and identified several covariates that explain IIV. Therapeutic drug monitoring may be beneficial for patients with a small body weight, older ages, carrying one ETI-responsive CFTR variant or those with no exocrine pancreatic insufficiency and especially for patients who combine these characteristics. Therapeutic drug monitoring may also prove to be useful in individuals experiencing adverse events, in those with reduced effectiveness, or to help manage non-adherence issues.

Real-world safety profile of elexacaftor/tezacaftor/ivacaftor: a disproportionality analysis using the U.S. FDA adverse event reporting system

Background

Elexacaftor/Tezacaftor/Ivacaftor (ETI) has demonstrated significant efficacy in enhancing clinical outcomes for patients with cystic fibrosis (CF). Despite this, comprehensive post-marketing assessments of its adverse drug events (ADEs) remain insufficient. This study aims to analyze the ADEs associated with ETI using the U.S. FDA Adverse Event Reporting System (FAERS).

Methods

We conducted a pharmacovigilance analysis utilizing FAERS data from Q4 2019 to Q3 2024. Reports of ADEs related to ETI were extracted, and disproportionality analyses-including Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and Multi-item Gamma Poisson Shrinker (MGPS)-were employed to evaluate signal strength. Additionally, a time-to-onset (TTO) analysis was performed.

Results

A total of 28,366 ETI-related ADEs were identified, spanning 27 organ systems. We identified 322 positive signals, with signals consistent with the drug label including headache (702 cases, ROR 2.75), infective pulmonary exacerbation of CF (691 cases, ROR 384.24), rash (538 cases, ROR 2.72), and cough (507 cases, ROR 3.79). Unexpected signals were also noted, such as anxiety (494 cases, ROR 4.16), depression (364 cases, ROR 4.59), insomnia (281 cases ROR 2.83), nephrolithiasis (79 cases, ROR 3.63) and perinatal depression (4 cases, ROR 13.59). The TTO analysis indicated that the median onset of ADEs was 70 days, with 37.08% occurring within the first month. Subgroup analyses revealed that females exhibited a higher reporting rank for mental disorder and constipation, whereas in males, they were insomnia, abdominal pain, and nasopharyngitis.

Conclusion

This study highlights both recognized and unexpected ADEs associated with ETI, underscoring the necessity for ongoing monitoring, particularly concerning psychiatric conditions. The subgroup analysis suggests a need for personalized treatment strategies to optimize patient care.

Pseudomonas aeruginosa supports the survival of Prevotella melaninogenica in a cystic fibrosis lung polymicrobial community through metabolic cross-feeding

Cystic fibrosis (CF) is a multi-organ genetic disorder that affects more than 100,000 individuals worldwide. Chronic respiratory infections are among the hallmark complications associated with CF lung disease, and these infections are often due to polymicrobial communities that colonize the airways of persons with CF (pwCF). Such infections are a significant cause of morbidity and mortality, with studies indicating that pwCF who are co-infected with more than one organism experience more frequent pulmonary exacerbations, leading to a faster decline in lung function. Previous work established an in vitro CF-relevant polymicrobial community model composed of P. aeruginosa, S. aureus, S. sanguinis, and P. melaninogenica. P. melaninogenica cannot survive in monoculture in this model. In this study, we leverage this model to investigate the interactions between P. aeruginosa and P. melaninogenica, allowing us to understand the mechanisms by which the two microbes interact to support the growth of P. melaninogenica specifically in the context of the polymicrobial community. We demonstrate a cross-feeding mechanism whereby P. melaninogenica metabolizes mucin into short-chain fatty acids that are in turn utilized by P. aeruginosa and converted into metabolites (succinate, acetate) that are cross-fed to P. melaninogenica, supporting the survival of this anaerobe in the CF lung-relevant model.

Efficacy of Adding Oral N acetyl Cysteine Supplement to the Cystic Fibrosis Treatment Regimen: A Randomized Quasi-Experimental Trial

Objective

This study investigated the efficacy of adding the oral N-acetyl cysteine (NAC) supplement to the cystic fibrosis (CF) treatment regimen compared to adding a placebo. It also studied the quality of life and respiratory indicators of patients aged 6-18 with mild-to-moderate pulmonary involvement.

Methods

This clinical trial was a randomized, quasi-experimental pilot and add-on therapy controlled with a placebo for 3 months. The case group received 200 mg of oral NAC three times a day. In contrast, the control group had a placebo in the same way. From the 2021 fall to the summer of 2022, 38 CF patients referred to Imam Hossein Children's Hospital Clinic were finally examined. They were clinically stable with a forced expiratory volume in the first second (FEV1) level of more than 50% and no history of underlying cardiovascular and renal diseases.

Findings

The differences between the groups were not significant. In the placebo group, key measures remained unchanged, whereas the NAC group had an improvement in the CF Questionnaire-Revised score but no notable changes in other indices. Overall, comparisons of forced vital capacity (FVC) between the groups showed no variation.

Conclusion

The indicators of FEV1, FVC, FEV1/FVC, forced expiratory flow between 25% and 75% of vital capacity, and the quality of life of the case group were not significantly different from those of the placebo group, and no significant differences were observed between this medicine and placebo.

Structural insights into the interaction between adenovirus C5 hexon and human lactoferrin

Adenovirus (AdV) infection of the respiratory epithelium is common but poorly understood. Human AdV species C types, such as HAdV-C5, utilize the Coxsackie-adenovirus receptor (CAR) for attachment and subsequently integrins for entry. CAR and integrins are however located deep within the tight junctions in the mucosa where they would not be easily accessible. Recently, a model for CAR-independent AdV entry was proposed. In this model, human lactoferrin (hLF), an innate immune protein, aids the viral uptake into epithelial cells by mediating interactions between the major capsid protein, hexon, and yet unknown host cellular receptor(s). However, a detailed understanding of the molecular interactions driving this mechanism is lacking. Here, we present a new cryo-EM structure of HAdV-5C hexon at high resolution alongside a hybrid structure of HAdV-5C hexon complexed with human lactoferrin (hLF). These structures reveal the molecular determinants of the interaction between hLF and HAdV-C5 hexon. hLF engages hexon primarily via its N-terminal lactoferricin (Lfcin) region, interacting with hexon's hypervariable region 1 (HVR-1). Mutational analyses pinpoint critical Lfcin contacts and also identify additional regions within hLF that critically contribute to hexon binding. Our study sheds more light on the intricate mechanism by which HAdV-C5 utilizes soluble hLF/Lfcin for cellular entry. These findings hold promise for advancing gene therapy applications and inform vaccine development.

IMPORTANCE

Our study delves into the structural aspects of adenovirus (AdV) infections, specifically HAdV-C5 in the respiratory epithelium. It uncovers the molecular details of a novel pathway where human lactoferrin (hLF) interacts with the major capsid protein, hexon, facilitating viral entry, and bypassing traditional receptors such as CAR and integrins. The study's cryo-EM structures reveal how hLF engages hexon, primarily through its N-terminal lactoferricin (Lfcin) region and hexon's hypervariable region 1 (HVR-1). Mutational analyses identify critical Lfcin contacts and other regions within hLF vital for hexon binding. This structural insight sheds light on HAdV-C5's mechanism of utilizing soluble hLF/Lfcin for cellular entry, holding promise for gene therapy and vaccine development advancements in adenovirus research.