Use of 2,6-diaminopurine as a potent suppressor of UGA premature stop codons in cystic fibrosis.

Nonsense mutations are responsible for around 10% of cases of genetic diseases, including cystic fibrosis. 2,6-diaminopurine (DAP) has recently been shown to promote efficient readthrough of UGA premature stop codons. In this study, we show that DAP can correct a nonsense mutation in the Cftr gene in vivo in a new CF mouse model, in utero, and through breastfeeding, thanks, notably, to adequate pharmacokinetic properties. DAP turns out to be very stable in plasma and is distributed throughout the body. The ability of DAP to correct various endogenous UGA nonsense mutations in the CFTR gene and to restore its function in mice, in organoids derived from murine or patient cells, and in cells from patients with cystic fibrosis reveals the potential of such readthrough-stimulating molecules in developing a therapeutic approach. The fact that correction by DAP of certain nonsense mutations reaches a clinically relevant level, as judged from previous studies, makes the use of this compound all the more attractive.

Beneficial short-term effect of autogenic drainage on peripheral resistance in childhood cystic fibrosis disease.

BACKGROUND: Airway clearance techniques are supposed to be a necessary adjunct for the enhancement of impaired peripheral clearance in cystic fibrosis (CF). The objective was to assess the effect of one physiotherapy session (autogenic drainage: AD) on mucus clearance (sputum wet weight) and impulse oscillometry system (IOS) indices, including those obtained from extended Resistance-Inertance-Compliance (eRIC) modelling, considering the degree of bronchial congestion. METHODS: Thirty children with CF (median age: 12.7 years) in a stable condition prospectively underwent IOS measurements at baseline and after AD. They were divided in two groups: with (visual analog scale of bronchial congestion by the physiotherapist ≥ 5/10) and without (scale < 5/10) bronchial congestion. Paired-comparison of the effects of AD on airway resistance measurements was done with Wilcoxon test. RESULTS: The congestion scale correlated with the wet weight of sputum production during the session (Pearson test: p < 0.0001, R = 0.66). Ten children had bronchial congestion and 20 were without congestion. In the whole group, R5-20 Hz significantly decreased after AD (P = 0.049), which was related to a decrease in the children with congestion (P = 0.025), whereas it was not significantly modified in the children without congestion (P = 0.327). The eRIC model allowed the calculation of the peripheral resistance of the respiratory system, which also decreased in the children with congestion (P = 0.037), however, not modified in the children without congestion (P = 0.390). CONCLUSION: One session of autogenic drainage has the ability to decrease peripheral resistance obtained from IOS measurements, more specifically in children with CF with moderate to severe bronchial congestion. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04094441.

Lumacaftor/Ivacaftor Population Pharmacokinetics in Pediatric Patients with Cystic Fibrosis: A First Step Toward Personalized Therapy.

BACKGROUND: A major breakthrough in cystic fibrosis (CF) therapy was achievedAQ1 with CFTR modulators. The lumacaftor/ivacaftor combination is indicated for the treatment of CF in pediatric patients above 6 years old. Pharmacokinetic (PK) studies of lumacaftor/ivacaftor in these vulnerable pediatric populations are AQ2crucial to optimize treatment protocols. OBJECTIVES AND METHODS: The objectives of this study were to describe the population PK (PPK) of lumacaftor and ivacaftor in children with CF, and to identify factors associated with interindividual variability. The association between drug exposure and clinical response was also investigated. RESULTS: A total of 75 children were included in this PPK study, with 191 concentrations available for each compound and known metabolites (lumacaftor, ivacaftor, ivacaftor-M1, and ivacaftor-M6). PPK analysis was performed using Monolix software. A large interindividual variability was observed. The main sources of interpatient variability identified were patient bodyweight and hepatic function (aspartate aminotransferase). Forced expiratory volume in the first second (FEV1) was statistically associated with the level of exposure to ivacaftor after 48 weeks of treatment. CONCLUSIONS: This study is the first analysis of lumacaftor/ivacaftor PPK in children with CF. These data suggest that dose adjustment is required after identifying variability factors to optimize efficacy. The use of therapeutic drug monitoring as a basis for dose adjustment in children with CF may be useful.

Real-world assessment of LCI following lumacaftor-ivacaftor initiation in adolescents and adults with cystic fibrosis.

Lung clearance index (LCI) is a biomarker of ventilation inhomogeneity. Data are scarce on its usefulness in daily practice for monitoring the effects of treatments in older children and adults with CF. In this French observational study of lumacaftor-ivacaftor, 63 of 845 patients (7.5%) had available LCI performed at baseline and at six (M6; n=34) or 12 months (M12; n=46) after lumacaftor-ivacaftor initiation. At inclusion, median [IQR] age was 16 years [13-17], ppFEV1 was 72.8 [59.6-80.7], and LCI was 12.3 [10.3-15.0]. At both M6 and M12, no statistically significant LCI increases of 0.13 units or 1.34% (95% CI: -4.85-7.53) and 0.6 units or 6.66% (95% CI: -0.03-13.5) were observed. Discordant results between LCI and ppFEV1 were observed in one-third of the patients. In daily practice, LCI monitoring in adolescents and young adults with moderate lung disease gives results that are more heterogenous than those reported in children with milder disease.

Phenotypic Presentations of Cystic Fibrosis in Children of African Descent.

The Robert Debre Pediatric Cystic Fibrosis (CF) centre, located in the North East of Paris, a multicultural area, is in charge of a cohort of around a hundred and sixty children diagnosed with CF. Between 2000 and 2019, the proportion of children of African descent in this centre increased from 2% to 10%. We report the clinical features of 17 children of African descent diagnosed with CF: 4 (23%) were diagnosed after a meconium ileus, 14 (83%) had exocrine pancreatic insufficiency, and 7 (41%) had early Pseudomonas aeruginosa infection before the age of two. Even though the majority of patients were diagnosed through NBS, the twenty-nine-mutation testing kit proved less effective in non-Caucasian populations, with a false negative rate of 25% in this series. CF is definitely not solely a Caucasian disease and the literature reveals similar phenotypes in Caucasian and African people provided that they present the same CFTR mutations. Clinicians have to keep in mind that the diagnosis of CF in patients of African descent must be evoked in the case of symptoms and a sweat test must be performed, despite a negative result for NBS.

Impulse oscillometry indices to detect an abnormal lung clearance index in childhood cystic fibrosis.

The objective of our cross-sectional study was to assess the relationships between indices of multiple breath washout (MBW) and impulse oscillometry system (IOS) in cystic fibrosis in forty consecutive children (median age 8.1 years) in stable conditions and to evaluate whether cut-off values of IOS indices may help to avoid MBW, which is time-consuming. IOS measurements took a median duration of 3 min, while MBW measurements took a median duration of 49 min. Lung Clearance Index (LCI2.5% ) depicted significant linear correlations with z-scores of R5Hz, R5-20Hz, X5Hz, AX, and Fres (r2 = 0.27 to 0.51). Receiver-operator characteristic curves were constructed and showed that the best compromise was obtained with the z-score of Fres, with a cut-off value of -1.37 that had a sensitivity of 0.966, a specificity of 0.636, and a negative predictive value of 0.875. This z-score is useful for excluding increased LCI2.5% when below -1.37 using the reference set of Gochicoa et al. In conclusion, IOS measurement is easily and rapidly obtained in children and may be clinically useful for excluding increased LCI2.5% , thus allowing the time-consuming MBW test to be avoided.

Very early glucose tolerance abnormalities in children with cystic fibrosis.

Diabetes is a comorbidity of cystic fibrosis (CF) that worsens prognosis. Abnormal glucose tolerance is associated with decreased lung function and poorer nutritional status. Data are lacking on glucose tolerance abnormalities in young children. We report three infants with abnormal glucose tolerance, beginning under the age of one year, including two cases of very early diabetes which started before the age of six months. None of our patients required long-term insulin treatment, and glycaemia spontaneously improved. All three patients had early pulmonary infection with Pseudomonas aeruginosa and poor nutritional status. This case series presents three unique patients with early dysglycaemia, then improvement over time. This adds to the understanding of the spectrum of early dysglycaemia in CF and highlights the difficulty of diagnosis in this age group.

Effect of one-year lumacaftor-ivacaftor treatment on glucose tolerance abnormalities in cystic fibrosis patients.

OBJECTIVES: To investigate the effects of 1-year lumacaftor-ivacaftor treatment on abnormalities in glucose tolerance (AGT) in Phe508del homozygous cystic fibrosis (CF) patients. METHODS: Untreated CF patients with glucose intolerance or newly diagnosed diabetes were included in a prospective, observational study. After 1-year lumacaftor-ivacaftor treatment, AGT were evaluated by using oral glucose tolerance test. RESULTS: Forty patients participated. 78% of patients had glucose intolerance and 22% diabetes at baseline. After one-year treatment, 50% of patients had normal glucose tolerance, 40% glucose intolerance, and 10% diabetes (p <0.001). The two-hour OGTT glycemia decreased from 171 (153-197) to 139 (117-162) mg/dL (p <0.001). 57.5% (n = 23) of patients improved their glucose tolerance with a significant decrease in both 1-hour (p<0.01) and 2-hour (p<0.001) OGTT glycemia. CONCLUSION: Improvements in AGT were observed following 1-year lumacaftor-ivacaftor treatment. Larger studies are needed to comprehensively assess CF transmembrane conductance regulator (CFTR) modulators.

A quality improvement program for adolescents with cystic fibrosis: focus on psychosocial skills.

BACKGROUND: The two pediatric cystic fibrosis centers (CFCs) in Paris (Robert Debré) and Nantes, France, have been developing therapeutic patient education (TPE) programs since 2006 and have been engaged in the pilot phase of the quality improvement program (QIP) named the Hospital Program to Improve Outcomes and Expertise in Cystic Fibrosis (PHARE-M) since 2011. The objective was to improve the FEV1 of the cohort of adolescents to prepare them for their optimal transition to an adult CFC. METHODS: The two CFCs formed a multidisciplinary quality team and used the analysis of causes of insufficient respiratory function taking into account the adolescents' psychosocial factors. At the Nantes CFC, the approach was centered on adolescents' body image and their motivation to take care of themselves by assigning specific aspects of patient follow-up to each professional in the team. At R. Debré, an individual cause-and-effect diagram identified for each patient the medical and psychosocial factors that could account for insufficient respiratory function. Personalized actions were offered to each patient. RESULTS: In 2014, the median FEV1 (Forced Expiratory Volume in 1 Second) of the adolescent cohort exceeds 90% at the 2 CFCs (Nantes and R. Debré). Between 2011 and 2014 both centers improved their ranking for FEV1% in adolescents in the Registry histograms. At R. Debré, the personalized process allowed to reinforce equality of care, offering to all the opportunity to benefit from TPE sessions and coaching with an adapted physical activity teacher. The psychologist developed a specific tool to support the patient-centered process. CONCLUSION: The link between TPE and QIP was strong at our two centers enhancing patient centered care and targeting an optimal transition to an adult program.

Central venous thrombosis and thrombophilia in cystic fibrosis: A prospective study.

BACKGROUND AND AIMS: Catheter venous thrombosis may result in life-threatening embolic complications. Recently, a thrombophilic tendency was described in cystic fibrosis (CF), the significance of which remains unclear. The aims of this study were to (1) document the frequency of catheter venous thrombosis detected by colour-Doppler-ultrasound (Doppler-US), (2) assess genetic and acquired thrombophilia risk factors for catheter venous thrombosis and hypercoagulability status and (3) provide recommendations on laboratory screening when considering insertion of a totally implantable vascular access device (TIVAD) in CF patients. METHODS: We designed a multicentre prospective study in patients selected at the time of catheter insertion. Doppler-US was scheduled at 1 and 6months after insertion and before insertion in case of a previous central line. Blood samplings were drawn at insertion and at 1 and 6months later. RESULTS: One-hundred patients received a TIVAD and 90 completed the 6-month study. Prevalence of thrombophilia abnormalities and hypercoagulability was found in 50% of the cohorts. Conversely, catheter venous thrombosis frequency was low (6.6%). CONCLUSION: Our data do not support biological screening at the time of a TIVAD insertion. We emphasise the contribution of a medical history of venous thromboembolism and prospective Doppler-US for identifying asymptomatic catheter venous thrombosis to select patients who may benefit from biological screening and possible anticoagulant therapy.

Recurrent abdominal pain in children with cystic fibrosis: a pilot prospective longitudinal evaluation of characteristics and management.

Children with cystic fibrosis commonly experience abdominal pain; however this remains poorly characterised. This prospective cross-sectional study with a longitudinal design, examined the prevalence, causes and effect of pain management via daily diaries, validated questionnaires for pain characteristics, anxiety status and quality of life. One hundred and thirty CF patients aged 8 to 18 years, regularly followed at our centre, were questioned on recurrent abdominal pain. Eight patients fulfilled the criteria; all wished to enter the study. Pain management included behavioural intervention with effective pain relief, and had a positive impact on anxiety and quality of life. This study is the first one to prospectively assess recurrent abdominal pain in CF. We documented a very low prevalence of 6%. We suggest that, ruling out abdominal discomfort, only a minority of CF children presented recurrent abdominal pain with a true negative impact on daily life. We emphasise the need for further studies including larger cohorts.

Clinical changes of patients with cystic fibrosis during transition from pediatric to adult care.

PURPOSE: To evaluate the clinical changes of adults with cystic fibrosis (CF) during transition from a pediatric to adult CF center. METHODS: Data were collected at the time of transfer, 1 year earlier and 1 year later, for all patients in our adult CF center arriving from one of the three pediatric CF centers in Paris between January 2001 and June 2004. RESULTS: Sixty-three of the 68 patients (transferred at a median age of 21.0 years) were regularly attending this adult CF center after 1 year and one had died. The mean number of outpatient visits increased in the year after transfer (5.7 vs. 3.8 in the year before, p < .001). The occurrence of clinical events and the rate of bronchial colonization did not change. Pseudomonas aeruginosa was found in about 60% of patients at any time. Pulmonary function declined regularly with no statistically significant difference in the rate of decline between the 2 years of follow-up (FEV 1 was 54.7% predicted at transfer). Nutritional status remained stable (mean body mass index was 19.1 kg/m2). The number and duration of oral and i.v. antibiotic courses did not change, but more patients received them at home (p < .001) and self-administered physiotherapy after transfer (p = .001). The proportion of students decreased from 79.3% to 48.1% (p = .02) and the proportion in the workforce increased from 12.7% to 20.4% after transfer. CONCLUSIONS: Patients with CF remained clinically stable during transition and progressively acquired autonomy.

Clinical outcome of cystic fibrosis presenting with or without meconium ileus: a matched cohort study.

OBJECTIVE: This matched case-control study compared the nutritional and the pulmonary long-term outcomes of cystic fibrosis (CF) patients presenting a history of meconium ileus (MI) with early-diagnosed symptomatic CF without MI (non-MI). MATERIAL AND METHOD: Twenty-six patients with CF treated for MI between 1980 and 1997 have been matched for sex, birth date, and earliest CF symptomatic diagnosis for the children with non-MI CF. Clinical characteristics, genotype and complications were evaluated as well as the progression of the CF disease from infancy to 15 years old by nutritional status (z score weight, z score height), pulmonary function tests (PFTs) (FVC and FEV1), and Pseudomonas aeruginosa acquisition. RESULTS: Median duration of the follow-up was 12.5 years (range, 10-17 years). Genotype identification showed no significant difference. Further on, the rate of complications and the occurrence of chronic P. aeruginosa colonization did not differ. At age of 15 years (n = 13), nutritional status and PFTs did not demonstrate any significant difference. CONCLUSION: These results suggest that adequate initial nutritional and medical management of MI allows further similar nutritional status and PFTs compared with other early-diagnosed symptomatic CF patients. In this study, MI did not represent an additional risk factor for the patient's life.