Efficacy of lumacaftor-ivacaftor for the treatment of cystic fibrosis patients homozygous for the F508del-CFTR mutation

Cystic fibrosis (CF) results from mutations in the CF transmembrane conductance regulator (CFTR) gene, which codes for the CFTR channel protein. The most common mutation in CF is F508del, which produces a misfolded protein with diminished channel activity. The development of small-molecule CFTR-modulator compounds offers an exciting and novel approach for pharmacological treatment of CF. The corrector lumacaftor helps rescue F508del-CFTR to the cell surface, and potentiator ivacaftor increases F508del-CFTR channel activity. The combination of lumacaftor-ivacaftor (Vertex Pharmaceuticals Incorporated) represents the first FDA-approved therapy for CF patients with two copies of the F508del mutation. Although this combination therapy is the first treatment to directly target the F508del-CFTR mutation, patients taking this drug displayed only modest improvements in lung function. This article summarizes recent data from clinical trials and research discoveries relating to the lumacaftor-ivacaftor treatment, and considers options for identifying future therapies that will be most efficacious for all CF patients

Persistent wheeze in infants: A guide for general pediatricians

Infants with persistent wheeze is a common diagnostic challenge for the general pediatrician because of the broad differential diagnoses. The initial diagnostic approach should include a comprehensive history, physical examination, and chest radiography. Additional testing may be warranted. Involvement of a pediatric pulmonary subspecialist may also be indicated

Use of telavancin in adolescent patients with cystic fibrosis and prior intolerance to vancomycin: A case series

The most common pathogen in pediatric cystic fibrosis (CF) patients is Staphylococcus aureus, and drug-resistant species are associated with negative outcomes. Methicillin-resistant Staphylococcus aureus (MRSA) is notoriously hard to treat because many antibiotics are not FDA approved for children and drug allergies or intolerances can prohibit the use of others. Telavancin is currently indicated for hospital-acquired pneumonia and ventilator-associated pneumonia caused by MRSA, but it has not been studied in patients with CF or in pediatrics. As a semi-synthetic derivative of vancomycin, it is unknown if cross-reactivity with telavancin occurs in patients with vancomycin hypersensitivity or intolerance. In this case series, we describe three adolescent patients with CF and previous intolerance to vancomycin who received telavancin for bronchopulmonary exacerbations

Positional impairment of gas exchange during diaphragm pacing alleviated by increasing amplitude settings in congenital central hypoventilation syndrome

Diaphragm pacing (DP) by phrenic nerve stimulation is a modality of chronic ventilatory support in individuals with congenital central hypoventilation syndrome (CCHS). We report a 9-year-old girl with CCHS who uses DP without tracheostomy during sleep. Her parents report hypoxemia and hypercapnia related to positional changes of the body during sleep requiring frequent adjustment of pacer settings. Overnight polysomnography was performed to titrate DP settings that showed adequate gas exchange in the supine position, but intermittent hypoxemia and hypercapnia were noted in the left decubitus position without obstructive sleep apnea occurring. Subsequently, the DP amplitude settings were increased during polysomnography, thereby identifying and treating positional hypoxemia and hypercapnia in various body positions. Our case emphasizes the importance of polysomnography in children with CCHS using DP to monitor for sleep-disordered breathing and titration of DP settings to achieve optimal oxygenation and ventilation with different body positions during sleep. © 2020 American Academy of Sleep Medicine. All rights reserved

Measured fetal and neonatal exposure to Lumacaftor and Ivacaftor during pregnancy and while breastfeeding

With the growing class of CFTR modulator therapy available to more patients and with increasing pregnancies in individuals with CF, there is a growing need to understand the effects of these agents during pregnancy. There are few reports of their continued use in the literature, although it is likely that this is not an uncommon occurrence. We report the uncomplicated and successful pregnancy of a woman treated with lumacaftor/ivacaftor, as well as the clinical course of the infant during the first 9 months of life. We also report drug levels in plasma from the mother, cord blood, breast milk, and infant to estimate fetal and infant drug exposure

Accumulation and persistence of ivacaftor in airway epithelia with prolonged treatment

Background: Current dosing strategies of CFTR modulators are based on serum pharmacokinetics, but drug concentrations in target tissues such as airway epithelia are not known. Previous data suggest that CFTR modulators may accumulate in airway epithelia, and serum pharmacokinetics may not accurately predict effects of chronic treatment. Methods: CF (F508del homozygous) primary human bronchial epithelial (HBE) cells grown at air-liquid interface were treated for 14 days with ivacaftor plus lumacaftor or ivacaftor plus tezacaftor, followed by a 14-day washout period. At various intervals during treatment and washout phases, drug concentrations were measured via mass spectrometry, electrophysiological function was assessed in Ussing chambers, and mature CFTR protein was quantified by Western blotting. Results: During treatment, ivacaftor accumulated in CF-HBEs to a much greater extent than either lumacaftor or tezacaftor and remained persistently elevated even after 14 days of washout. CFTR activity peaked at 7 days of treatment but diminished with further ivacaftor accumulation, though remained above baseline even after washout. Conclusions: Intracellular accrual and persistence of CFTR modulators during and after chronic treatment suggest complex pharmacokinetic and pharmacodynamic properties within airway epithelia that are not predicted by serum pharmacokinetics. Direct measurement of drugs in target tissues may be needed to optimize dosing strategies, and the persistence of CFTR modulators after treatment cessation has implications for personalized medicine approaches

Clinical outcomes in cystic fibrosis patients with Trichosporon respiratory infection

Background Relationships between clinical outcomes and novel respiratory pathogens such as Trichosporon are not well understood. Methods Respiratory cultures from CF patients were screened for novel pathogens Trichosporon and Chryseobacterium as well as other pathogens over 28 months. Relationships between microbiologic and clinical data were assessed using univariate and multivariate methods. Results Of 4934 respiratory cultures from 474 CF patients, 37 cultures from 10 patients were Trichosporon positive. Patients with positive Trichosproron cultures had a greater decline in FEV1 over time (− 3.9%/year vs. -1.3%/year, p < 0.05), whereas Chryseobacterium did not influence lung function. These findings were confirmed in multivariate analyses that included age, gender, and other common pathogens as confounders. Treatment of Trichosporon infected patients was associated with improved lung function. Conclusions Trichosporon can be recovered from a small but clinically meaningful fraction of CF patients. The presence of Trichosporon, but not Chryseobacterium, is associated with greater declines in lung function

Challenging scenarios in nontuberculous mycobacterial infection in cystic fibrosis

This review summarizes the discussion of a session held during the 2018 North American Cystic Fibrosis (CF) Conference titled “Challenging Cases in Nontuberculous Mycobacterial (NTM) Management.” In this session, a multidisciplinary panel of NTM experts discussed clinical challenges related to the management of NTM infection in people with CF in which decision-making falls outside of the Cystic Fibrosis Foundation/European Cystic Fibrosis Society NTM guidelines. Topics discussed included managing newly acquired NTM infection, selecting and monitoring treatment regimens, determining treatment endpoints, and caring for patients after NTM treatment

Highlights from the 2015 North American Cystic Fibrosis Conference

The 29th Annual North American Cystic Fibrosis Conference was held in Phoenix, Arizona on October 8-10, 2015. Abstracts were published in a supplement to Pediatric Pulmonology.1 In this review, we summarize presentations in several of the topic areas addressed at the conference. Our goal is to provide an overview of presentations with relevance to emerging or changing concepts in several areas rather than a comprehensive review. Citations from the conference are by first author and abstract number or symposium number, as designated in the supplement

Outcomes associated with antibiotic regimens for treatment of Mycobacterium abscessus in cystic fibrosis patients

Background Mycobacterium abscessus infection is associated with declining lung function in cystic fibrosis (CF), but there is little evidence on clinical efficacy to guide treatment. Methods Retrospective review of 37 CF patients treated for M. abscessus respiratory infection at a single center from 2006 to 2014. Outcomes included change in FEV1 at 30, 60, 90, 180, and 365 days after treatment and clearance of M. abscessus from sputum cultures. Results Lung function was significantly improved after 30 and 60 days of treatment, but not at later time points. Gains were inversely related to starting lung function. Antibiotic choices did not influence outcomes except for greater clearance with clarithromycin. Conclusions Treatment of M. abscessus resulted in short term improvement in lung function that is inversely related to pre-treatment FEV1