Dataset Information

Rationalizing endpoints for prospective studies of pulmonary exacerbation treatment response in cystic fibrosis.

ABSTRACT:

Background

Given the variability in pulmonary exacerbation (PEx) management within and between Cystic Fibrosis (CF) Care Centers, it is possible that some approaches may be superior to others. A challenge with comparing different PEx management approaches is lack of a community consensus with respect to treatment-response metrics. In this analysis, we assess the feasibility of using different response metrics in prospective randomized studies comparing PEx treatment protocols.

Methods

Response parameters were compiled from the recent STOP (Standardized Treatment of PEx) feasibility study. Pulmonary function responses (recovery of best prior 6-month and 12-month FEV₁% predicted and absolute and relative FEV₁% predicted improvement from treatment initiation) and sign and symptom recovery from treatment initiation (measured by the Chronic Respiratory Infection Symptom Score [CRISS]) were studied as categorical and continuous variables. The proportion of patients retreated within 30days after the end of initial treatment was studied as a categorical variable. Sample sizes required to adequately power prospective 1:1 randomized superiority and non-inferiority studies employing candidate endpoints were explored.

Results

The most sensitive endpoint was mean change in CRISS from treatment initiation, followed by mean absolute FEV₁% predicted change from initiation, with the two responses only modestly correlated (R²=.157; P<0.0001). Recovery of previous best FEV₁ was a problematic endpoint due to missing data and a substantial proportion of patients beginning PEx treatment with FEV₁ exceeding their previous best measures (12.1% >12-month best, 19.6% >6-month best). Although mean outcome measures deteriorated approximately 2-weeks post-treatment follow-up, the effect was non-uniform: 62.7% of patients experienced an FEV₁ worsening versus 49.0% who experienced a CRISS worsening.

Conclusions

Results from randomized prospective superiority and non-inferiority studies employing mean CRISS and FEV₁ change from treatment initiation should prove compelling to the community. They will need to be large, but appear feasible.

SUBMITTER: VanDevanter DR

PROVIDER: S-EPMC6581041 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

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Publications

Rationalizing endpoints for prospective studies of pulmonary exacerbation treatment response in cystic fibrosis.

VanDevanter D R DR Heltshe S L SL Spahr J J Beckett V V VV Daines C L CL Dasenbrook E C EC Gibson R L RL Raksha Jain J Sanders D B DB Goss C H CH Flume P A PA

Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society 20170421 5

<h4>Background</h4>Given the variability in pulmonary exacerbation (PEx) management within and between Cystic Fibrosis (CF) Care Centers, it is possible that some approaches may be superior to others. A challenge with comparing different PEx management approaches is lack of a community consensus with respect to treatment-response metrics. In this analysis, we assess the feasibility of using different response metrics in prospective randomized studies comparing PEx treatment protocols.<h4>Methods ...[more]

PMID: 28438499

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Project description:Rationale: Pulmonary exacerbations (PExs) are associated with significant morbidity in people with cystic fibrosis (CF). Severe PExs are treated with intravenous antibiotics, including tobramycin. CF care guidelines recommend continuing chronic maintenance medications during PEx treatment. Azithromycin (AZM) is one of the most widely prescribed chronic medications for CF in the United States. Recent evidence has identified a potential antagonistic relationship between AZM and tobramycin.Objectives: To determine whether, among PEx treated with intravenous tobramycin, concomitant AZM use is associated with worse clinical outcomes.Methods: Retrospective cohort study using the CF Foundation Patient Registry-Pediatric Health Information System (CFFPR-PHIS)-linked dataset. People with CF age 6-21 years were included if they were hospitalized between 2006 and 2016 for a PEx. Inverse probability of treatment weighing was used to minimize the effects of confounders, including indication bias. Associations of concomitant treatment with AZM and lung function outcomes were determined using linear mixed-effect models and generalized estimating equations. Cox proportional hazard regression models were used to evaluate associations with time to next PEx.Results: Among the 10,660 people with CF included in the CFFPR-PHIS-linked dataset, 2,294 children and adolescents with 5,022 PExs that had intravenous tobramycin use were identified. A little less than half (n = 2,247; 45%) of all PExs were treated concomitantly with AZM and intravenous tobramycin. AZM use both at the most recent outpatient clinic encounter and during PEx treatment in combination with intravenous tobramycin was associated with a significantly lower absolute improvement in percentage-predicted forced expiratory volume in 1 second (ppFEV1) (-0.93%; 95% confidence interval [CI], -1.78 to -0.07; P = 0.033), a lesser odds of returning to 90% or more of baseline ppFEV1 (odds ratio, 0.79; 95% CI, 0.68-0.93; P = 0.003), and a shorter time to next PEx requiring intravenous antibiotics (hazard ratio, 1.22; 95% CI, 1.14-1.31; P < 0.001) compared with intravenous tobramycin use without concomitant AZM.Conclusions: Concomitant AZM and intravenous tobramycin use for in-hospital PEx treatment was associated with poorer clinical outcomes than treatment with intravenous tobramycin without AZM. These results support the hypothesis that an antagonistic relationship between these two medications might exist.

Project description:BackgroundPulmonary exacerbations (PExs) are clinically important in people with cystic fibrosis (CF). Multiple definitions have been used for PEx, and this scoping review aimed to identify the different definitions reported in the literature and to ascertain which signs and symptoms are commonly used to define them.MethodsA search was performed using Embase, MEDLINE, Cochrane Library, Scopus and CINAHL. All publications reporting clinical trials or prospective observational studies involving definitions of PEx in people with CF published in English from January 1990 to December 2022 were included. Data were then extracted for qualitative thematic analysis.ResultsA total of 14 039 records were identified, with 7647 titles and abstracts screened once duplicates were removed, 898 reviewed as full text and 377 meeting the inclusion criteria. Pre-existing definitions were used in 148 publications. In 75% of papers, an objective definition was used, while 25% used a subjective definition, which subcategorised into treatment-based definitions (76%) and those involving clinician judgement (24%). Objective definitions were subcategorised into three groups: those based on a combination of signs and symptoms (50%), those based on a predefined combination of signs and symptoms plus the initiation of acute treatment (47%) and scores involving different clinical features each with a specific weighting (3%). The most common signs and symptoms reported in the definitions were, in order, sputum production, cough, lung function, weight/appetite, dyspnoea, chest X-ray changes, chest sounds, fever, fatigue or lethargy and haemoptysis.ConclusionWe have identified substantial variation in the definitions of PEx in people with CF reported in the literature. There is a requirement for the development of internationally agreed-upon, standardised and validated age-specific definitions. Such definitions would allow comparison between studies and effective meta-analysis to be performed and are especially important in the highly effective modulator therapy era in CF care.

Project description:Adults with cystic fibrosis (CF) frequently harbor Staphylococcus aureus, which is increasingly antibiotic resistant. Telavancin is a once-daily rapidly bactericidal antibiotic active against methicillin-, linezolid-, and ceftaroline-resistant S. aureus Because CF patients experience alterations in pharmacokinetics, the optimal dose of telavancin in this population is unknown. Adult CF patients (n?=?18) admitted for exacerbations received 3 doses of telavancin 7.5?mg/kg of body weight (first 6 patients) or 10?mg/kg (final 12 patients) every 24?h (q24h). Population pharmacokinetic models with and without covariates were fitted using the nonparametric adaptive grid algorithm in Pmetrics. The final model was used to perform 5,000-patient Monte Carlo simulations for multiple telavancin doses. The best fit was a 2-compartment model describing the volume of distribution of the central compartment (Vc ) as a multiple of total body weight (TBW) and the volume of distribution of the central compartment scaled to total body weight (V ?) normalized by the median observed value (Vc ?=?V ??×?TBW/52.1) and total body clearance (CL) as a linear function of creatinine clearance (CRCL) (CL?=?CLNR?+?CL??×?CRCL), where CLNR represents nonrenal clearance and CL? represents the slope term on CRCL to estimate renal clearance. The mean population parameters were as follows: V ?, 4.92? ± 0.76 liters?·?kg-1; CLNR, 0.59? ± 0.30 liters?·?h-1; CL?, 5.97?×?10-3 ± 1.24?×?10-3; Vp (volume of the peripheral compartment), 3.77? ± 1.41 liters; Q (intercompartmental clearance), 4.08? ± 2.17 liters?·?h-1 The free area under the concentration-time curve (fAUC) values for 7.5 and 10?mg/kg were 30? ± 4.6 and 52? ± 12?mg?·?h/liter, respectively. Doses of 7.5?mg/kg and 10?mg/kg achieved 76.5% and 100% probability of target attainment (PTA) at a fAUC/MIC threshold of >215, respectively, for MIC of ?0.12?mg/liter. The probabilities of reaching the acute kidney injury (AKI) threshold AUC (763?mg?·?h?·?liter-1) for these doses were 0% and 0.96%, respectively. No serious adverse events occurred. Telavancin 10?mg/kg yielded optimal PTA and minimal risk of AKI, suggesting that this FDA-approved dose is appropriate to treat acute pulmonary exacerbations in CF adults. (The clinical trial discussed in this study has been registered at ClinicalTrials.gov under identifier NCT03172793.).

Dataset Information

Rationalizing endpoints for prospective studies of pulmonary exacerbation treatment response in cystic fibrosis.

Background

Methods

Results

Conclusions

Publications

Rationalizing endpoints for prospective studies of pulmonary exacerbation treatment response in cystic fibrosis.

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