Influence of age on diurnal variability in measurements of spirometric indices and respiratory pressures

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.

Effects of repetition as training and incentives on the performance in pulmonary function tests in healthy volunteers

Pulmonary function testing (PFT) is a central part of diagnosis and treatment monitoring in respiratory medicine. Few studies have investigated whether repeated PFT or training can significantly influence performance. To investigate potential training effects of repeated PFT, 30 healthy volunteers underwent daily and weekly repeated PFT with spirometry over 10 weeks. The study included 22 females and 8 males with a mean age of 31.8 years ± 15 (SD), a mean weight of 66.3 kg ± 14.5 (SD) and a mean BMI of 22.4 ± 3.3 (SD). The first 5 PFTs were performed on 5 consecutive days, followed by 3 PFTs once a week on the same day of the week. Subsequently, 5 measurements were taken daily for 5 consecutive days. After these 13 appointments in 5 weeks, participants were randomly assigned to the control or incentive group, with stratification for age and gender. The incentive group had the opportunity to win money (200 €) for the highest increase in forced vital capacity (FVC). PFTs were performed once a week on the same day of the week as before for 5 more times. Motivation was assessed by a questionnaire before the 1st, 9th and 18th measure of PFT at three time points throughout the study. An increase in PFT was observed with mean increases of 473 [ml] in FVC, 395 [ml] in forced expiratory volume in 1 s (FEV1) and 1.382 [litres/second] in peak expiratory flow (PEF) after four days of daily PFT. These increases did not persist and spirometric data returned to baseline after one week. After allocation, participants in the incentive group did not increase their FVC, FEV1 or PEF compared to the control group. The incentive group showed higher motivation than the control group, even before allocation. Repeated daily PFT could induce short-term increases, but PFT does not fluctuate significantly in the long term. External influences that affect motivation could not consistently increase PFT. For clinical practice, it can be concluded that PFT does not necessarily require extended training to ensure reliability if reproducibility criteria are met.

Respiratory performance of humans exposed to moderate levels of carbon dioxide

In a business as usual scenario, atmospheric carbon dioxide concentration (CO₂ ) could reach 950 parts per million (ppm) by 2100. Indoor CO₂ concentrations will rise consequently, given its dependence on atmospheric CO₂ levels. If buildings are ventilated following current standards in 2100, indoor CO₂ concentration could be over 1300 ppm, depending on specific ventilation codes. Such exposure to CO₂ could have physiological and psychological effects on building occupants. We conducted a randomized, within-subject study, examining the physiological effects on the respiratory functions of 15 persons. We examined three exposures, each 150 min long, with CO₂ of: 900 ppm (reference), 1450 ppm (decreased ventilation), and 1450 ppm (reference condition with added pure CO₂ ). We measured respiratory parameters with capnometry and forced vital capacity (FVC) tests. End-tidal CO₂ and respiration rates did not significantly differ across the three exposures. Parameters measured using FVC decreased significantly from the start to the end of exposure only at the reduced ventilation condition (p < 0.04, large effect size). Hence, poor ventilation likely affects respiratory parameters. This effect is probably not caused by increased CO₂ alone and rather by other pollutants-predominantly human bioeffluents in this work-whose concentrations increased as a result.

Lung physiology and controlled exposure study design

Controlled human inhalation exposure ( CHIE) studies provide a unique opportunity to conduct formal experiments to examine the human health effects of airborne pollutants. Lung function, easily measured using spirometry, is a common physiological variable often utilized in these studies. By design, CHIE studies only induce mild and reversible acute effects, which may or may not predict adverse effects that may develop under chronic exposure conditions. There is substantial inter- and intra-individual variability in functional capacity and symptoms such as chest tightness and dyspnea, which are complex variables that are affected by individual perception, physiological lung impairment, and other variables (e.g., concomitant health conditions, and level of conditioning/fitness). Thus, the design of the CHIE study and physiological and environmental factors of study participants can affect each CHIE study's results. Researchers can address many of these critical issues in the problem formulation phase of CHIE studies, utilizing existing information on the expected effects of the substance of interest and possible modes of action. Thoughtful design and interpretation of CHIE studies will increase their utility for evaluating and setting environmental health policy.

CFTR function and clinical response to modulators parallel nasal epithelial organoid swelling

In vitro biomarkers to assess cystic fibrosis transmembrane conductance regulator activity are desirable for precision modulator selection and as a tool for clinical trials. Here, we describe an organoid swelling assay derived from human nasal epithelia using commercially available reagents and equipment and an automated imaging process. Cells were collected in nasal brush biopsies, expanded in vitro, and cultured as spherical organoids or as monolayers. Organoids were used in a functional swelling assay with automated measurements and analysis, whereas monolayers were used for short-circuit current measurements to assess ion channel activity. Clinical data were collected from patients on modulators. Relationships between swelling data and short-circuit current, as well as between swelling data and clinical outcome measures, were assessed. The organoid assay measurements correlated with short-circuit current measurements for ion channel activity. The functional organoid assay distinguished individual responses as well as differences between groups. The organoid assay distinguished incremental drug responses to modulator monotherapy with ivacaftor and combination therapy with ivacaftor, tezacaftor, and elexacaftor. The swelling activity paralleled the clinical response. In conclusion, an in vitro biomarker derived from patients' cells can be used to predict responses to drugs and is likely to be useful as a preclinical tool to aid in the development of novel treatments and as a clinical trial outcome measure for a variety of applications, including gene therapy or editing.

Predictive factors for lumacaftor/ivacaftor clinical response

BACKGROUND

Ivacaftor-lumacaftor combination therapy corrects the F508 del-CFTR mutated protein which causes Cystic Fibrosis. The clinical response of the patients treated with the combination therapy is highly variable. This study aimed to determine factors involved in the individual's response to lumacaftor-ivacaftor therapy.

METHODS

Sweat test was assessed at baseline and after 6 months of ivacaftor-lumacaftor treatment in 41 homozygous F508del children and young adults. β-adrenergic peak sweat secretion, nasal potential difference (NPD) and intestinal current measurements (ICM) were performed in patients accepting these tests. Seric level of lumacaftor and ivacaftor were determined and additional CFTR variant were searched.

RESULTS

Sweat chloride concentration significantly decreased after treatment, whereas the β-adrenergic peak sweat response did not vary in 9 patients who underwent these tests. The average level of F508del-CFTR activity rescue reached up to 15% of the normal level in intestinal epithelium, as studied by ICM in 12 patients (p = .03) and 20% of normal in the nasal epithelium in NPD tests performed in 21 patients (NS). There was no significant correlation between these changes and improvements in FEV₁ at 6 months. Serum drug levels did not correlate with changes in FEV₁, BMI-Zscore or other CFTR activity biomarkers. Additional exonic variants were identified in 4 patients. The F87L-I1027T-F508del-CFTR complex allele abolished the lumacaftor corrector effect.

CONCLUSION

This observational study investigates a number of potential factors linked to the clinical response of F508del homozygous patients treated with lumacaftor-ivacaftor combination therapy. Lumacaftor and ivacaftor blood levels are not associated with the clinical response. Additional exonic variants may influence protein correction.

Electrically induced mechanomyograms reflect inspiratory muscle strength in young or elderly subjects

BACKGROUND

Respiratory muscle strength has been used as a tool for evaluating respiratory rehabilitation in chronic obstructive pulmonary disease. However, mouth pressure measurement evaluated by maximum expiratory mouth pressure (PEmax) or inspiratory mouth pressure (PImax) offers an indirect method for measuring respiratory muscle strength. We demonstrated the evaluation of diaphragm contractility using a mechanomyogram (MMG), which is the mechanical signal generated by the motion of the diaphragm induced by the electric stimulation of the phrenic nerve.

METHODS

Study participants were 21 young and 20 elderly subjects with no symptoms of respiratory disease. The elderly subjects were divided into non-smoker or smoker groups. The smoker group was defined as subjects having a Brinkman Index of greater than 300. We measured basic spirometric parameters, mouth pressure (PEmax, PImax), and diaphragmatic MMG.

RESULTS

Diaphragmatic MMG showed more clear contrast between young subjects and elderly non-smoker or smoker subjects than the conventional method for respiratory muscle contraction (PEmax, PImax). In addition, the diaphragmatic MMG strongly correlated with inspiratory muscle strength.

CONCLUSIONS

Diaphragmatic MMG may reflect diaphragmatic contractility more directly and sensitively than the conventional method.

The changes of pulmonary function and pulmonary strength according to time of day: a preliminary study

[Purpose] The purpose of this study was to identify changes in pulmonary function and pulmonary strength according to time of day. [Subjects and Methods] The subjects were 20 healthy adults who had no cardiopulmonary-related diseases. Pulmonary function and pulmonary strength tests were performed on the same subjects at 9:00 am, 1:00 pm, and 5:00 pm. The pulmonary function tests included forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and forced expiratory flow between 25 and 75% of vital capacity (FEF25-75%). Pulmonary strength tests assessed maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP). [Results] FEV1 showed statistically significant differences according to time of day. Other pulmonary function and pulmonary strength tests revealed no statistical differences in diurnal variations. [Conclusion] Our findings indicate that pulmonary function and pulmonary strength tests should be assessed considering the time of day and the morning dip phenomenon.

Diurnal variations in the parameters of pulmonary function and respiratory muscle strength in patients with COPD

OBJECTIVE

To evaluate the magnitude of diurnal changes in the parameters of pulmonary function and respiratory muscle strength/endurance in a sample of patients with COPD.

METHODS

A group of 7 patients underwent spirometry, together with determination of MIP and MEP, at two distinct times (between 8:00 and 8:30 a.m. and between 4:30 and 5:00 p.m.) on a single day. Between assessments, the patients remained at rest in the laboratory.

RESULTS

In accordance with the Global Initiative for Chronic Obstructive Pulmonary Disease staging system, COPD was classified as moderate, severe, and very severe in 1, 3, and 3 of the patients, respectively. From the first to the second assessment, there were significant decreases in FVC, FEV1, and MEP (of 13%, 15%, and 10%, respectively), as well as (less than significant) decreases in PEF, MIP, and maximal voluntary ventilation (of 9%, 3%, and 11%, respectively).

CONCLUSIONS

In this sample of COPD patients, there were diurnal variations in the parameters of pulmonary function and respiratory muscle strength. The values of FEV1, FVC, and MEP were significantly lower in the afternoon than in the morning.

Sustained 24-hour efficacy of once daily indacaterol (300 μg) in patients with chronic obstructive pulmonary disease: a randomized, crossover study

PURPOSE

Indacaterol is a novel, once daily, inhaled ultra-long-acting β₂-agonist for the treatment of chronic obstructive pulmonary disease (COPD). Here we compared the 24-h spirometry profile of once daily indacaterol 300 μg with that of placebo and twice daily salmeterol 50 μg in patients with COPD.

METHODS

This randomized, multicenter, placebo-controlled, crossover study comprised three 14-day treatment periods (with 14-day washouts). Patients (male/female ≥ 40 years) with moderate-to-severe COPD were randomized to receive double-blind indacaterol 300 μg or placebo once daily, or open-label salmeterol 50 μg twice daily. The primary outcome measure was 24-h post-dose (trough) FEV₁ (mean of FEV₁ at 23 h 10 min and 23 h 45 min post-indacaterol dose) after 14 days. FEV₁ was assessed at multiple time points on Days 1 and 14 of each treatment period. Safety and tolerability were also monitored.

RESULTS

Of 68 randomized patients, 61 completed. Trough FEV₁ (primary endpoint) on Day 14 for indacaterol was 200 mL higher than placebo (p < 0.001), exceeding the prespecified minimum clinically important difference (120 mL), and was 90 mL higher than for salmeterol (p = 0.011). After Day 1, trough FEV(1) for indacaterol was 150 mL higher than placebo (p < 0.001). Indacaterol provided superior bronchodilation compared with placebo (p < 0.001) across the full 24-h assessment period on Days 1 and 14. In addition, on both days, indacaterol provided superior FEV₁ compared with salmeterol (p < 0.05) at many post-baseline time points, including 5 min post-dose. All treatments were well tolerated.

CONCLUSIONS

Once daily indacaterol 300 μg produced effective sustained 24-h bronchodilation from the first dose, an efficacy profile superior to placebo and twice daily salmeterol. Given its effective bronchodilation with once daily dosing, indacaterol is likely to be a useful treatment option for patients with moderate-to-severe COPD.

Circadian-rhythm differences among emergency department patients with chronic obstructive pulmonary disease exacerbation

The purpose of the study was determine whether patients with chronic obstructive pulmonary disease (COPD) exacerbation who present to the emergency department (ED) during the night (00:00 to 07:59 h) vs. other times of the day have more severe COPD exacerbation, require more intensive treatment, and have worse clinical outcomes. A multicenter cohort study was completed involving 29 EDs in the United States and Canada. Using a standard protocol, consecutive ED patients with COPD exacerbation were interviewed, and their charts were reviewed. Of 582 patients enrolled, 52% were women, and the median age was 71 yrs (interquartile range, 64-77 yrs). Nighttime patients (15% of cohort) did not differ from patients presenting at other times except that they were less likely to have private insurance, more likely to have a history of corticosteroid use, and have a shorter duration of symptoms exacerbation. Except for a few features indicative of more severe COPD exacerbation (such as higher respiratory rate at ED presentation, greater likelihood of receiving noninvasive positive pressure ventilation, and increased risk of endotracheal intubation), nighttime patients did not differ from other patients with respect to ED management. Nighttime patients were approximately three-fold more likely to be intubated in the ED (odds ratio, 3.46; 95% confidence interval, 1.10-10.9). There were no day-night differences regarding ED disposition and post-ED relapse. Except for some features indicating more severe exacerbation, nighttime ED patients had similar chronic COPD characteristics, received similar treatments in the ED, and had similar clinical outcomes compared with patients presenting to the ED at other times of the day.

Fast onset of effect of budesonide/formoterol versus salmeterol/fluticasone and salbutamol in patients with chronic obstructive pulmonary disease and reversible airway obstruction

BACKGROUND AND OBJECTIVES

Data on the onset of action of COPD medications are lacking. This study compared the onset of bronchodilation following different inhaled therapies in patients with moderate-to-severe COPD and reversible airway obstruction.

METHODS

In this double-blind, double-dummy, crossover study, 90 patients (aged >or=40 years; FEV(1) 30-70% predicted) were randomized to a single dose (two inhalations) of budesonide/formoterol 160/4.5 microg, salmeterol/fluticasone 25/250 microg, salbutamol 100 microg or placebo (via pressurized metered-dose inhalers) on four visits. The primary end-point was change in FEV(1) 5 min after drug inhalation; secondary end-points included inspiratory capacity (IC) and perception of onset of effect.

RESULTS

Budesonide/formoterol significantly improved FEV(1) at 5 min compared with placebo (P < 0.0001) and salmeterol/fluticasone (P = 0.0001). Significant differences were first observed at 3 min. Onset of effect was similar with budesonide/formoterol and salbutamol. Improvements in FEV(1) following active treatments were superior to placebo after 180 min (all P < 0.0001); both combinations were better than salbutamol at maintaining FEV(1) improvements (P <or= 0.0001) at 180 min. Active treatments improved IC at 15 and 185 min compared with placebo (P < 0.0001). Maximal IC was greater with budesonide/formoterol than salmeterol/fluticasone (P = 0.0184) at 65 min. Patients reported a positive response to the perceptions of the onset of effect question shortly after receiving active treatments (median time to onset 5 min for active treatments vs 20 min for placebo), with no significant difference between active treatments.

CONCLUSION

Budesonide/formoterol has an onset of bronchodilatory effect in patients with COPD and reversible airway obstruction that is faster than salmeterol/fluticasone and similar to salbutamol.

Diurnal variability of peak expiratory flow

Diurnal variation in peak expiratory flow (PEFvar) has been suggested as a surrogate for bronchial hyperreactivity, and may be a useful tool in the management of bronchial asthma. Several indices have been postulated to measure PEFvar; however, the number of daily measurements and the timing of recordings are not clearly established. Although several investigators have defined ranges for PEFvar in healthy individuals, clear cutoff values that differentiate asthmatics from others are not available. Despite this shortcoming, PEFvar is an important measurement in screening and diagnosis of asthma in population-based studies, as well as for assessing disease severity and prognosis. Treatment of asthma with either inhaled corticosteroids or bronchodilators may influence the magnitude of PEFvar in a complex fashion. Therefore, PEFvar should only be interpreted in conjunction with other clinical and laboratory information.

Do bacteria cause exacerbations of COPD?

Exacerbations of COPD, which include combinations of dyspnea, cough, wheezing, increased sputum production (and a change in its color to green or yellow), are common. The role of bacterial infection in causing these episodes and the value of antibiotic therapy for them are debated. An assessment of the microbiological studies indicates that conventional bacterial respiratory pathogens, such as Streptococcus pneumoniae and Haemophilus influenzae, are absent in about 50% of attacks. The frequency of isolating these organisms, which often colonize the bronchi of patients in stable condition, does not seem to increase during exacerbations, and their density typically remains unchanged. Serologic studies generally fail to show rises in antibody titers to H influenzae; the only report available demonstrates none to Haemophilus parainfluenzae; and the sole investigation of S pneumoniae is inconclusive. Trials with vaccines against S pneumoniae and H influenzae show no clear benefit in reducing exacerbations. The histologic findings of bronchial biopsies and cytologic studies of sputum show predominantly increased eosinophils, rather than neutrophils, contrary to what is expected with bacterial infections. The randomized, placebo-controlled trials generally show no benefit for antibiotics, but most have studied few patients. A meta-analysis of these demonstrated no clinically significant advantage to antimicrobial therapy. The largest trials suggest that antibiotics confer no advantage for mild episodes; with more severe attacks, in which patients should receive systemic corticosteroids, the addition of antimicrobial therapy is probably not helpful.