Association of Inhaled Antibiotics in Addition to Standard Intravenous Therapy and Outcomes of Pediatric Inpatient Pulmonary Exacerbations

Update on the diagnosis and management of cystic fibrosis pulmonary exacerbations

Pulmonary exacerbations in people with cystic fibrosis are associated with significant morbidity and reduced quality of life. Pulmonary exacerbation treatment guidelines, published by an expert panel assembled by the Cystic Fibrosis Foundation nearly 15 years ago, were primarily consensus-based as there were several gaps in the evidence base. In particular, limited evidence existed regarding optimal pulmonary exacerbation treatment strategies, including duration of antibiotic therapy, treatment location, antibiotic selection, and the role of systemic corticosteroids. Over the last decade, results from observational studies and large multi-center randomized controlled trials have begun to answer important questions related to pulmonary exacerbation treatment. This review focuses on the diagnosis, etiology, and changing epidemiology of pulmonary exacerbations, and also summarizes the most recent and up-to-date studies describing pulmonary exacerbation treatment. Finally, this review provides consideration for future pulmonary exacerbation research priorities, particularly in the current highly effective modulator therapy era.

Drugs, Drugs, Drugs: Current Treatment Paradigms in Cystic Fibrosis Airway Infections

Airway infections have remained a prominent feature in persons living with cystic fibrosis (CF) despite the dramatic improvements in survival in the past decades. Antimicrobials are a cornerstone of infection management for both acute and chronic maintenance indications. Historic clinical trials of antimicrobials in CF have led to the adoption of consensus guidelines for their use in clinical care. More recently, however, there are efforts to re-think the optimal use of antimicrobials for care with the advent of novel and highly effective CF transmembrane conductance regulator modulator therapies. Encouragingly, however, drug development has remained active concurrently in this space. Our review focuses on the evidence for and perspectives regarding antimicrobial use in both acute and maintenance settings in persons with CF. The therapeutic innovations in CF and how this may affect antimicrobial approaches are also discussed.

Clinical Outcomes of Antipseudomonal versus Other Antibiotics Among Children with Cystic Fibrosis without Pseudomonas aeruginosa

RATIONALE

Antibiotic selection for pulmonary exacerbation (PEx) management in children with CF is typically guided by prior respiratory culture results. While antipseudomonal antibiotics are often used in children with chronic Pseudomonas aeruginosa (Pa) airway infection, no data exist to guide antibiotic selection in children who are culture negative for Pa for ≥1 year.

OBJECTIVES

To determine among children classified as 1-, 2-, or 3-years Pa-negative if PEx treatment with at least 1 oral and/or intravenous anti-Pa antibiotic is associated with improved clinical outcomes compared to treatment with antibiotics not effective against Pa.

METHODS

Retrospective cohort study using the linked CF Foundation Patient Registry-Pediatric Health Information System (CFFPR-PHIS) database. We included children 6-21 years old hospitalized between 2008-2018 consistently culture-negative for Pa 1 year prior to a study PEx. Children were classified as 1- or 2-years Pa-negative if their last Pa-positive culture occurred in the 13-24 months or 25-36 months prior to a study PEx, respectively, with all subsequent cultures negative for Pa. Children classified as 3-years Pa-negative had no Pa-positive cultures in the 36 months prior to a study PEx. Inverse probability of treatment weighted linear or logistic regression models were used to compare clinical outcomes (pre- to post-PEx forced expiratory volume in one second, odds of returning to ≥90% of baseline lung function, and odds of having a future PEx) between anti-Pa and non-anti-Pa antibiotic strategies.

RESULTS

Among all children included in the linked dataset, 1,290 children with 2,347 PEx were eligible for analysis. Among all study PEx, 530, 326, and 1,491 PEx were classified as 1-, 2-, or 3-years Pa-negative, respectively, and anti-Pa antibiotics were administered in 79%, 67%, and 66% of all PEx classified as 1-, 2-, or 3-years Pa-negative, respectively. For all Pa-negative groups, when compared to non-anti-Pa antibiotic regimens, anti-Pa antibiotic treatment was not associated with greater improvement in any studied clinical outcomes.

CONCLUSIONS

Despite its common use, including antibiotics effective against Pa may provide no additional benefit for PEx treatment among children who are Pa-negative for at least 1 year prior. Prospective trials are warranted to directly test this hypothesis.

Association Between Number of Intravenous Antipseudomonal Antibiotics and Clinical Outcomes of Pediatric Cystic Fibrosis Pulmonary Exacerbations

BACKGROUND

Pulmonary exacerbations (PEx) in people with cystic fibrosis (PwCF) are associated with significant morbidity. While standard PEx treatment for PwCF with Pseudomonas aeruginosa infection includes two IV antipseudomonal antibiotics, little evidence exists to recommend this approach. This study aimed to compare clinical outcomes of single versus double antipseudomonal antibiotic use for PEx treatment.

METHODS

Retrospective cohort study using the linked CF Foundation Patient Registry-Pediatric Health Information System dataset. PwCF were included if hospitalized between 2007-2018 and 6-21 years of age. Regression modeling accounting for repeated measures was used to compare lung function outcomes between single versus double IV antipseudomonal antibiotic regimens using propensity-score weighting to adjust for relevant confounding factors.

RESULTS

Among 10,660 PwCF in the dataset, we analyzed 2,578 PEx from 1,080 PwCF, of which 455 and 2,123 PEx were treated with 1 versus 2 IV antipseudomonal antibiotics, respectively. We identified no significant differences between PEx treated with 1 versus 2 IV antipseudomonal antibiotics either in change between pre- and post-PEx percent predicted forced expiratory volume in one second (ppFEV1) (-0.84%, [95% CI -2.25, 0.56]; p=0.24), odds of returning to ≥90% of baseline ppFEV1 within 3 months following PEx (Odds Ratio 0.83, [95% CI 0.61, 1.13]; p=0.24) or time to next PEx requiring IV antibiotics (Hazard Ratio 1.04, [95% CI 0.87, 1.24]; p=0.69).

CONCLUSION

Use of 2 IV antipseudomonal antibiotics for PEx treatment in young PwCF was not associated with greater improvements in measured respiratory and clinical outcomes compared to treatment with 1 IV antipseudomonal antibiotic.

Cystic Fibrosis: Recent Insights into Inhaled Antibiotic Treatment and Future Perspectives

Although new inhaled antibiotics have profoundly improved respiratory diseases in cystic fibrosis (CF) patients, lung infections are still the leading cause of death. Inhaled antibiotics, i.e., colistin, tobramycin, aztreonam lysine and levofloxacin, are used as maintenance treatment for CF patients after the development of chronic Pseudomonas aeruginosa (P. aeruginosa) infection. Their use offers advantages over systemic therapy since a relatively high concentration of the drug is delivered directly to the lung, thus, enhancing the pharmacokinetic/pharmacodynamic parameters and decreasing toxicity. Notably, alternating treatment with inhaled antibiotics represents an important strategy for improving patient outcomes. The prevalence of CF patients receiving continuous inhaled antibiotic regimens with different combinations of the anti-P. aeruginosa antibiotic class has been increasing over time. Moreover, these antimicrobial agents are also used for preventing acute pulmonary exacerbations in CF. In this review, the efficacy and safety of the currently available inhaled antibiotics for lung infection treatment in CF patients are discussed, with a particular focus on strategies for eradicating P. aeruginosa and other pathogens. Moreover, the effects of long-term inhaled antibiotic therapy for chronic P. aeruginosa infection and for the prevention of pulmonary exacerbations is reviewed. Finally, how the mucus environment and microbial community richness can influence the efficacy of aerosolized antimicrobial agents is discussed.