Safety of aerosol tobramycin administration for 3 months to patients with cystic fibrosis

Effect of Disinfection Method and Testing Methodology on the Performance of a Breath-Enhanced Jet Nebulizer

National guidelines for cystic fibrosis recommend cleaning and disinfecting nebulizers after each use. We tested two groups of five reusable breath-enhanced nebulizers after 0, 5, 10, 15, 20, 30, 60, 90, 120, 150, and 180 sterilization (baby bottle sterilizer) or cleaning cycles. The nebulizers were operated for 7 min (6 L/min) after loading albuterol (2.5 mg/3 mL), and they were evaluated with and without breathing simulation after cleaning/sterilization (0-180 and 0-60 cycles, respectively). Over the course of 180 cleaning/sterilization cycles, the mean (SD) solution output was 1.33 mL (0.12 mL)/1.29 mL (0.08 mL); the nebulizer mass remaining in the nebulizer was 61.5% (5.2%)/63% (4%); sputtering time was 4.7 min (0.8 min)/4.8 s (0.6 min); inspiratory filter was 19% (3%)/18.5% (2.4%); expiratory filter was 6.7% (1.1%)/6.7% (0.8%); and difference in drug output calculated using the solution output and nebulizer mass was 6.8% (4%)/5.2% (2.9%). Thermal disinfection with a baby-bottle sterilizer did not alter the performance of a reusable breath-enhanced nebulizer. The nebulizer test performed without breathing simulation underestimated its performance. The calculation of the drug output based on the solution output resulted in its overestimation.

Role of inhaled antibiotics in the era of highly effective CFTR modulators

Recurrent and chronic bacterial infections are common in people with cystic fibrosis (CF) and contribute to lung function decline. Antibiotics are the mainstay in the treatment of exacerbations and chronic bacterial infection in CF. Inhaled antibiotics are effective in treating chronic respiratory bacterial infections and eradicating Pseudomonas aeruginosa from the respiratory tract, with limited systemic adverse effects. In the past decade, highly effective cystic fibrosis transmembrane conductance regulator (CFTR) modulators have become a new therapy that partially corrects/opens chloride transport in patients with selected CFTR mutations, restoring mucus hydration and improving mucociliary clearance. The recent triple CFTR modulator combination is approved for ∼80-90% of the CF population and significantly reduces pulmonary exacerbations and improves respiratory symptoms and lung function. CFTR modulators have shifted the focus from symptomatic treatment to personalised/precision medicine by targeting genotype-specific CFTR defects. While these are highly effective, they do not fully normalise lung physiology, stop inflammation or resolve chronic lung damage, such as bronchiectasis. The impact of these new drugs on lung health is likely to change the future management of chronic pulmonary infections in people with CF. This article reviews the role of inhaled antibiotics in the era of CFTR modulators.

Inhaled anti-pseudomonal antibiotics for long-term therapy in cystic fibrosis

BACKGROUND

Inhaled antibiotics are commonly used to treat persistent airway infection with Pseudomonas aeruginosa that contributes to lung damage in people with cystic fibrosis. Current guidelines recommend inhaled tobramycin for individuals with cystic fibrosis and persistent Pseudomonas aeruginosa infection who are aged six years or older. The aim is to reduce bacterial load in the lungs so as to reduce inflammation and deterioration of lung function. This is an update of a previously published review.

OBJECTIVES

To evaluate the effects of long-term inhaled antibiotic therapy in people with cystic fibrosis on clinical outcomes (lung function, frequency of exacerbations and nutrition), quality of life and adverse events (including drug-sensitivity reactions and survival).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched ongoing trials registries. Date of last search: 28 June 2022.

SELECTION CRITERIA

We selected trials where people with cystic fibrosis received inhaled anti-pseudomonal antibiotic treatment for at least three months, treatment allocation was randomised or quasi-randomised, and there was a control group (either placebo, no placebo or another inhaled antibiotic).

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, judged the risk of bias, extracted data from these trials and judged the certainty of the evidence using the GRADE system.

MAIN RESULTS

The searches identified 410 citations to 125 trials; 18 trials (3042 participants aged between five and 45 years) met the inclusion criteria. Limited data were available for meta-analyses due to the variability of trial design and reporting of results. A total of 11 trials (1130 participants) compared an inhaled antibiotic to placebo or usual treatment for a duration between three and 33 months. Five trials (1255 participants) compared different antibiotics, two trials (585 participants) compared different regimens of tobramycin and one trial (90 participants) compared intermittent tobramycin with continuous tobramycin alternating with aztreonam. One trial (18 participants) compared an antibiotic to placebo and also to a different antibiotic and so fell into both groups. The most commonly studied antibiotic was tobramycin which was studied in 12 trials. Inhaled antibiotics compared to placebo We found that inhaled antibiotics may improve lung function measured in a variety of ways (4 trials, 814 participants). Compared to placebo, inhaled antibiotics may also reduce the frequency of exacerbations (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.47 to 0.93; 3 trials, 946 participants; low-certainty evidence). Inhaled antibiotics may lead to fewer days off school or work (quality of life measure) (mean difference (MD) -5.30 days, 95% CI -8.59 to -2.01; 1 trial, 245 participants; low-certainty evidence). There were insufficient data for us to be able to report an effect on nutritional outcomes and there was no effect on survival. There was no effect on antibiotic resistance seen in the two trials that were included in meta-analyses. We are uncertain of the effect of the intervention on adverse events (very low-certainty evidence), but tinnitus and voice alteration were the only events occurring more often in the inhaled antibiotics group. The overall certainty of evidence was deemed to be low for most outcomes due to risk of bias within the trials and imprecision due to low event rates. Different antibiotics or regimens compared Of the eight trials comparing different inhaled antibiotics or different antibiotic regimens, there was only one trial for each unique comparison. We found no differences between groups for any outcomes except for the following. Aztreonam lysine for inhalation probably improved forced expiratory volume at one second (FEV1) % predicted compared to tobramycin (MD -3.40%, 95% CI -6.63 to -0.17; 1 trial, 273 participants; moderate-certainty evidence). However, the method of defining the endpoint was different to the remaining trials and the participants were exposed to tobramycin for a long period making interpretation of the results problematic. We found no differences in any measure of lung function in the remaining comparisons. Trials measured pulmonary exacerbations in different ways and showed no differences between groups except for aztreonam lysine probably leading to fewer people needing treatment with additional antibiotics than with tobramycin (RR 0.66, 95% CI 0.51 to 0.86; 1 trial, 273 participants; moderate-certainty evidence); and there were fewer hospitalisations due to respiratory exacerbations with levofloxacin compared to tobramycin (RR 0.62, 95% CI 0.40 to 0.98; 1 trial, 282 participants; high-certainty evidence). Important treatment-related adverse events were not very common across comparisons, but were reported less often in the tobramycin group compared to both aztreonam lysine and colistimethate. We found the certainty of evidence for these comparisons to be directly related to the risk of bias within the individual trials and varied from low to high.

AUTHORS' CONCLUSIONS

Long-term treatment with inhaled anti-pseudomonal antibiotics probably improves lung function and reduces exacerbation rates, but pooled estimates of the level of benefit were very limited. The best evidence available is for inhaled tobramycin. More evidence from trials measuring similar outcomes in the same way is needed to determine a better measure of benefit. Longer-term trials are needed to look at the effect of inhaled antibiotics on quality of life, survival and nutritional outcomes.

Application of aerosol therapy in respiratory diseases in children: A Saudi expert consensus

The Saudi Pediatric Pulmonology Association (SPPA) is a subsidiary of the Saudi Thoracic Society (STS), which consists of a group of Saudi experts with well-respected academic and clinical backgrounds in the fields of asthma and other respiratory diseases. The SPPA Expert Panel realized the need to draw up a clear, simple to understand, and easy to use guidance regarding the application of different aerosol therapies in respiratory diseases in children, due to the high prevalence and high economic burden of these diseases in Saudi Arabia. This statement was developed based on the available literature, new evidence, and experts' practice to come up with such consensuses about the usage of different aerosol therapies for the management of respiratory diseases in children (asthma and nonasthma) in different patient settings, including outpatient, emergency room, intensive care unit, and inpatient settings. For this purpose, SPPA has initiated and formed a national committee which consists of experts from concerned specialties (pediatric pulmonology, pediatric emergency, clinical pharmacology, pediatric respiratory therapy, as well as pediatric and neonatal intensive care). These committee members are from different healthcare sectors in Saudi Arabia (Ministry of Health, Ministry of Defence, Ministry of Education, and private healthcare sector). In addition to that, this committee is representing different regions in Saudi Arabia (Eastern, Central, and Western region). The subject was divided into several topics which were then assigned to at least two experts. The authors searched the literature according to their own strategies without central literature review. To achieve consensus, draft reports and recommendations were reviewed and voted on by the whole panel.

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.

Noncystic fibrosis bronchiectasis management: opportunities and challenges

PURPOSE OF REVIEW

Noncystic fibrosis bronchiectasis is a challenging disease which carries a heavy healthcare burden and significant mortality and morbidity. This review highlights the challenges in the diagnosis of bronchiectasis and discusses the management strategies and research opportunities in this field.

RECENT FINDINGS

The challenges in the management of bronchiectasis appear to be multifactorial, arising from both etiological heterogeneity and disease-specific management. Frequent inflammation and infections not only lead to progressive respiratory failure but also increase the risk of cardiovascular complications. No therapies are approved specifically for adult bronchiectasis, but new guidelines and recent studies outline strategies for control of infection and inflammation and for prevention of frequent exacerbations to improve overall prognosis.

SUMMARY

Recent studies in the management of bronchiectasis are encouraging. Advances have been made in understanding both disease heterogeneity and best practices for care; interventions such as daily mucociliary clearance, eradication of colonized microbial organisms, and control of inflammation may result in favorable outcomes.

Off-label use of intravenous antimicrobials for inhalation in patients with cystic fibrosis

Management of infections in patients with cystic fibrosis (CF) presents challenges for healthcare providers, including the eradication of initial acquisition, treatment of acute exacerbations, and chronic infection with suppressive therapy. Inhaled antimicrobial therapy for infections in patients with CF has been used in these capacities, often in an effort to achieve optimal concentrations in sputum for antimicrobial efficacy while mitigating potential toxicities associated with systemic therapy. Unfortunately, there are few commercially available products formulated for inhalation, resulting in the off-label use of other formulations, such as intravenous products, administered via nebulization. This review aims to examine the evidence supporting the efficacy of these off-label formulations for management of acute and chronic infections associated with CF, as well as adverse effects associated with their use.

Inhaled anti-pseudomonal antibiotics for long-term therapy in cystic fibrosis

BACKGROUND

Inhaled antibiotics are commonly used to treat persistent airway infection with Pseudomonas aeruginosa that contributes to lung damage in people with cystic fibrosis. Current guidelines recommend inhaled tobramycin for individuals with cystic fibrosis and persistent Pseudomonas aeruginosa infection who are aged six years or older. The aim is to reduce bacterial load in the lungs so as to reduce inflammation and deterioration of lung function. This is an update of a previously published review.

OBJECTIVES

To evaluate the effects long-term inhaled antibiotic therapy in people with cystic fibrosis on clinical outcomes (lung function, frequency of exacerbations and nutrition), quality of life and adverse events (including drug sensitivity reactions and survival).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched ongoing trials registries.Date of last search: 13 February 2018.

SELECTION CRITERIA

We selected trials if inhaled anti-pseudomonal antibiotic treatment was used for at least three months in people with cystic fibrosis, treatment allocation was randomised or quasi-randomised, and there was a control group (either placebo, no placebo or another inhaled antibiotic).

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, judged the risk of bias, extracted data from these trials and judged the quality of the evidence using the GRADE system.

MAIN RESULTS

The searches identified 333 citations to 98 trials; 18 trials (3042 participants aged between five and 56 years) met the inclusion criteria. Limited data were available for meta-analyses due to the variability of trial design and reporting of results. A total of 11 trials (1130 participants) compared an inhaled antibiotic to placebo or usual treatment for a duration between three and 33 months. Five trials (1255 participants) compared different antibiotics, two trials (585 participants) compared different regimens of tobramycin and one trial (90 participants) compared intermittent tobramycin with continuous tobramycin alternating with aztreonam. One of the trials (18 participants) compared to placebo and a different antibiotic and so fell into both groups. The most commonly studied antibiotic was tobramycin which was studied in 12 trials.We found limited evidence that inhaled antibiotics improved lung function (four of the 11 placebo-controlled trials, n = 814). Compared to placebo, inhaled antibiotics also reduced the frequency of exacerbations (three trials, n = 946), risk ratio 0.66 (95% confidence interval (CI) 0.47 to 0.93). There were insufficient data for us to be able to report an effect on nutritional outcomes or survival and there were insufficient data for us to ascertain the effect on quality of life. There was no significant effect on antibiotic resistance seen in the two trials that were included in meta-analyses. Tinnitus and voice alteration were the only adverse events significantly more common in the inhaled antibiotics group. The overall quality of evidence was deemed to be low for most outcomes due to risk of bias within the trials and imprecision due to low event rates.Of the eight trials that compared different inhaled antibiotics or different antibiotic regimens, there was only one trial in each comparison. Forced expiratory volume at one second (FEV₁) % predicted was only found to be significantly improved with aztreonam lysine for inhalation compared to tobramycin (n = 273), mean difference -3.40% (95% CI -6.63 to -0.17). However, the method of defining the endpoint was different to the remaining trials and the participants were exposed to tobramycin for a long period making interpretation of the results problematic. No significant differences were found in the remaining comparisons with regard to lung function. Pulmonary exacerbations were measured in different ways, but one trial (n = 273) found that the number of people treated with antibiotics was lower in those receiving aztreonam than tobramycin, risk ratio 0.66 (95% CI 0.51 to 0.86). We found the quality of evidence for these comparisons to be directly related to the risk of bias within the individual trials and varied from low to high.

AUTHORS' CONCLUSIONS

Inhaled anti-pseudomonal antibiotic treatment probably improves lung function and reduces exacerbation rate, but pooled estimates of the level of benefit were very limited. The best evidence is for inhaled tobramycin. More evidence from trials measuring similar outcomes in the same way is needed to determine a better measure of benefit. Longer-term trials are needed to look at the effect of inhaled antibiotics on quality of life, survival and nutritional outcomes.

Inhaled Antibiotic Therapy in Chronic Respiratory Diseases

The management of patients with chronic respiratory diseases affected by difficult to treat infections has become a challenge in clinical practice. Conditions such as cystic fibrosis (CF) and non-CF bronchiectasis require extensive treatment strategies to deal with multidrug resistant pathogens that include Pseudomonas aeruginosa, Methicillin-resistant Staphylococcus aureus, Burkholderia species and non-tuberculous Mycobacteria (NTM). These challenges prompted scientists to deliver antimicrobial agents through the pulmonary system by using inhaled, aerosolized or nebulized antibiotics. Subsequent research advances focused on the development of antibiotic agents able to achieve high tissue concentrations capable of reducing the bacterial load of difficult-to-treat organisms in hosts with chronic respiratory conditions. In this review, we focus on the evidence regarding the use of antibiotic therapies administered through the respiratory system via inhalation, nebulization or aerosolization, specifically in patients with chronic respiratory diseases that include CF, non-CF bronchiectasis and NTM. However, further research is required to address the potential benefits, mechanisms of action and applications of inhaled antibiotics for the management of difficult-to-treat infections in patients with chronic respiratory diseases.

The effects of inhaled aztreonam on the cystic fibrosis lung microbiome

BACKGROUND

Aztreonam lysine for inhalation (AZLI) is an inhaled antibiotic used to treat chronic Pseudomonas aeruginosa infection in CF. AZLI improves lung function and quality of life, and reduces exacerbations-improvements attributed to its antipseudomonal activity. Given the extremely high aztreonam concentrations achieved in the lower airways by nebulization, we speculate this may extend its spectrum of activity to other organisms. As such, we sought to determine if AZLI affects the CF lung microbiome and whether community constituents can be used to predict treatment responsiveness.

METHODS

Patients were included if they had chronic P. aeruginosa infection and repeated sputum samples collected before and after AZLI. Sputum DNA was extracted, and the V3-hypervariable region of the 16S ribosomal RNA (rRNA) gene amplified and sequenced.

RESULTS

Twenty-four patients naïve to AZLI contributed 162 samples. The cohort had a median age of 37.1 years, and a  median FEV₁ of 44% predicted. Fourteen patients were a priori defined as responders for achieving ≥3% FEV₁ improvement following initiation. No significant changes in alpha diversity were noted following AZLI. Furthermore, beta diversity demonstrated clustering with respect to patients, but had no association with AZLI use. However, we did observe a decline in the relative abundance of several individual operational taxonomic units (OTUs) following AZLI initiation suggesting that specific sub-populations of organisms may be impacted. Patients with higher abundance of Staphylococcus and anaerobic organisms including Prevotella and Fusobacterium were less likely to respond to therapy.

CONCLUSIONS

Results from our study suggest potential alternate/additional mechanisms by which AZLI functions. Moreover, our study suggests that the CF microbiota may be used as a biomarker to predict patient responsiveness to therapy suggesting the microbiome may be harnessed for the personalization of therapies.

Management of Pulmonary Disease in Patients with Cystic Fibrosis

Cystic fibrosis is the most common, life-shortening autosomal recessive disease, affecting approximately 1 in 3400 live births in the United States. Gastrointestinal and pulmonary manifestations are most common. With the introduction of pancreatic enzyme and vitamin supplementation, lung disease accounts for the vast majority of morbidity and mortality in patients with cystic fibrosis. The lungs of cystic fibrosis patients are essentially normal at birth but demonstrate evidence of airway inflammation and infection in early infancy. A vicious cycle of inflammation, infection and obstruction ultimately leads to destruction of airways, impairment of gas exchange and death.

Current pharmacological management of pulmonary disease targets reducing airway obstruction, controlling infection and more recently, controlling inflammation. An increased recovery of unusual and highly resistant bacteria from patients with more advanced disease has been observed. Aggressive treatment of acute pulmonary exacerbations with combination antibiotic therapy for two to three weeks has shown pronounced beneficial effects. The routine use of prophylactic antistaphylococcal antibiotics is still controversial.

Although current pharmacologic treatment is symptomatic, new agents are being developed and studied that target the underlying defect in the CFTR protein. This review focuses on current pharmacologic management of pulmonary disease in patients with cystic fibrosis and the role of new agents emerging for the treatment of this disease.

Tolerability and Pharmacokinetic Evaluation of Inhaled Dry Powder Tobramycin Free Base in Non-Cystic Fibrosis Bronchiectasis Patients

Rationale

Bronchiectasis is a condition characterised by dilated and thick-walled bronchi. The presence of Pseudomonas aeruginosa in bronchiectasis is associated with a higher hospitalisation frequency and a reduced quality of life, requiring frequent and adequate treatment with antibiotics.

Objectives

To assess local tolerability and the pharmacokinetic parameters of inhaled excipient free dry powder tobramycin as free base administered with the Cyclops dry powder inhaler to participants with non-cystic fibrosis bronchiectasis. The free base and absence of excipients reduces the inhaled powder dose.

Methods

Eight participants in the study were trained in handling the device and inhaling correctly. During drug administration the inspiratory flow curve was recorded. Local tolerability was assessed by spirometry and recording adverse events. Serum samples were collected before, and 15, 30, 45, 60, 75, 90, 105, 120 min; 4, 8 and 12 h after inhalation.

Results and Discussion

Dry powder tobramycin base was well tolerated and mild tobramycin-related cough was reported only once. A good drug dose-serum concentration correlation was obtained. Relatively small inhaled volumes were computed from the recorded flow curves, resulting in presumably substantial deposition in the central airways—i.e., at the site of infection.

Conclusions

In this first study of inhaled dry powder tobramycin free base in non-cystic fibrosis bronchiectasis patients, the free base of tobramycin and the administration with the Cyclops dry powder device were well tolerated. Our data support further clinical studies to evaluate safety and efficacy of this compound in this population.

Management of Pseudomonas aeruginosa infection in cystic fibrosis patients using inhaled antibiotics with a focus on nebulized liposomal amikacin

Pseudomonas aeruginosa (PsA) is a highly prevalent bacterial organism recovered from the lungs of cystic fibrosis (CF) patients and chronic PsA infection is linked to progressive pulmonary function decline. The eradication and treatment of this organism from CF airways is particularly challenging to CF care providers. Aerosolized antibiotics that target PsA help to slow down growth, maintain lung function and reduce the frequency of pulmonary exacerbations. In this review, we discuss the currently available inhaled antibiotics for management of PsA lung infections in CF patients, with a focus on liposomal amikacin for inhalation (LAI). LAI is a unique formulation of amikacin under development that enhances drug delivery and retention in CF airways via drug incorporation into neutral liposomes. Factors such as once-daily dosing, mucus and biofilm penetration and potentially prolonged off-drug periods make LAI a potentially attractive option to manage chronic PsA lung infections in CF patients.

Pharmacokinetic and pharmacodynamic implications in inhalable antimicrobial therapy

Inhaled antimicrobials provide a promising alternative to the systemically delivered drugs for the treatment of acute and chronic lung infections. The delivery of antimicrobials via inhalation route decreases the systemic exposure while increasing the local concentration in the lungs, enabling the use of antimicrobials with severe systemic side effects. The inhalation route of administration has several challenges in pharmacokinetic (PK) and pharmacodynamic (PD) assessments. This review discusses various issues that need to be considered during study, data analysis, and interpretation of PK and PD of inhaled antimicrobials. Advancements overcoming the challenges are also discussed.

Long-term safety and efficacy of tobramycin in the management of cystic fibrosis

Cystic fibrosis (CF) is a fatal inherited disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene whose mortality is conditioned by a progressive decline in lung function. Bacterial infections play a key role in this decline. Chronic bacterial infection in CF patients varies over time and the presence of Pseudomonas aeruginosa in sputum is a marker of poor prognosis. P. aeruginosa is eradicated from the airways using inhaled antibiotics administered in various formulations and devices. Antipseudomonal antibiotics have extended the survival of CF patients to 40 years. Tobramycin is a bactericidal aminoglycoside antibiotic with demonstrated activity against gram-negative microorganisms. Initially, the drug was administered as an inhaled parenteral solution. Subsequently, a specific tobramycin inhalation solution was developed. PulmoSphere™ technology enables dry tobramycin powder to be formulated for inhalation (tobramycin inhalation powder) using a small and portable capsule-based breath-activated device (T-326). Chronic colonization by P. aeruginosa is the main indication for aerosol antibiotic therapy. The American Cystic Fibrosis Foundation, European guidelines, and Spanish consensus guidelines provide different recommendations for eradication.

Pharmacokinetics and pharmacodynamics of aerosolized antibacterial agents in chronically infected cystic fibrosis patients

Bacteria adapt to growth in lungs of patients with cystic fibrosis (CF) by selection of heterogeneously resistant variants that are not detected by conventional susceptibility testing but are selected for rapidly during antibacterial treatment. Therefore, total bacterial counts and antibiotic susceptibilities are misleading indicators of infection and are not helpful as guides for therapy decisions or efficacy endpoints. High drug concentrations delivered by aerosol may maximize efficacy, as decreased drug susceptibilities of the pathogens are compensated for by high target site concentrations. However, reductions of the bacterial load in sputum and improvements in lung function were within the same ranges following aerosolized and conventional therapies. Furthermore, the use of conventional pharmacokinetic/pharmacodynamic (PK/PD) surrogates correlating pharmacokinetics in serum with clinical cure and presumed or proven eradication of the pathogen as a basis for PK/PD investigations in CF patients is irrelevant, as minimization of systemic exposure is one of the main objectives of aerosolized therapy; in addition, bacterial pathogens cannot be eradicated, and chronic infection cannot be cured. Consequently, conventional PK/PD surrogates are not applicable to CF patients. It is nonetheless obvious that systemic exposure of patients, with all its sequelae, is minimized and that the burden of oral treatment for CF patients suffering from chronic infections is reduced.

Potentiation effects of amikacin and fosfomycin against selected amikacin-nonsusceptible Gram-negative respiratory tract pathogens

The amikacin-fosfomycin inhalation system (AFIS) is a combination of 2 antibiotics and an in-line nebulizer delivery system that is being developed for adjunctive treatment of pneumonia caused by Gram-negative organisms in patients on mechanical ventilation. AFIS consists of a combination of amikacin and fosfomycin solutions at a 5:2 ratio (amikacin, 3 ml at 100 mg/ml; fosfomycin, 3 ml at 40 mg/ml) and the PARI Investigational eFlow Inline System. In this antibiotic potentiation study, the antimicrobial activities of amikacin and fosfomycin, alone and in a 5:2 combination, were assessed against 62 Gram-negative pathogens from a worldwide antimicrobial surveillance collection (SENTRY). The amikacin MICs for 62 isolates of Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae were ≥32 μg/ml (intermediate or resistant according to the Clinical and Laboratory Standards Institute [CLSI]; resistant according to the European Committee on Antimicrobial Susceptibility Testing [EUCAST]). Each isolate was tested against amikacin (0.25 to 1,024 μg/ml), fosfomycin (0.1 to 409.6 μg/ml), and amikacin-fosfomycin (at a 5:2 ratio) using CLSI reference agar dilution methods. The median MIC values for amikacin and fosfomycin against the 62 isolates each decreased 2-fold with the amikacin-fosfomycin (5:2) combination from that with either antibiotic alone. Interactions between amikacin and fosfomycin differed by isolate and ranged from no detectable interaction to high potentiation. The amikacin-fosfomycin (5:2) combination reduced the amikacin concentration required to inhibit all 62 isolates from >1,024 to ≤ 256 μg/ml and reduced the required fosfomycin concentration from 204.8 to 102.4 μg/ml. These results support continued development of the amikacin-fosfomycin combination for aerosolized administration, where high drug levels can be achieved.

Tobramycin Inhalation Powder (TIP): An Efficient Treatment Strategy for the Management of Chronic Pseudomonas Aeruginosa Infection in Cystic Fibrosis

Repeated bouts of acute and chronic lung infections are responsible for progressive pulmonary function decline in individuals with cystic fibrosis (CF), ultimately leading to respiratory failure and death. Pseudomonas aeruginosa is the archetypical CF pathogen, causes chronic infection in 70% of individuals, and is associated with an accelerated clinical decline. The management of P. aeruginosa in CF has been revolutionized with the development and widespread use of inhaled antibiotics. Aerosol delivery of antimicrobial compounds in CF enables extremely high concentrations of antibiotics to be reached directly at the site of infection potentially overcoming adaptive resistance and avoiding the potential for cumulative systemic toxicities. Tobramycin inhalation powder (TIP) represents the first dry powder inhaled (DPI) antibiotic available for use in CF. DPIs are notable for a markedly reduced time for administration, ease of portability, and increased compliance. TIP has been developed as a therapeutic alternative to tobramycin inhalation solution (TIS), the standard of care for the past 20 years within CF. Relative to TIS 300 mg nebulized twice daily in on-and-off cycles of 28 days duration, TIP 112 mg twice daily via the T-326 inhaler administered on the same schedule is associated with marked time savings, increased patient satisfaction, and comparable clinical end points. TIP represents an innovative treatment strategy for those individuals with CF and holds the promise of increased patient compliance and thus the potential for improved clinical outcomes.

Therapeutic approaches to chronic cystic fibrosis respiratory infections with available, emerging aerosolized antibiotics

Chronic airway infection and inflammation are key events in the clinical course of cystic fibrosis (CF). The most relevant, best investigated strain of bacteria in these circumstances is Pseudomonas aeruginosa. Since pulmonary infection with P. aeruginosa is localized in the lower conducting airways, treatment is accessible with the use of inhaled aerosolized antibiotics. Tobramycin inhalation solution was the first antibiotic to be developed and approved (in 1998) for use as an aerosolized antibiotic in patients with CF. The only other aerosolized antibiotic indicated for this use is aztreonam lysine solution for inhalation, which has been approved by both European and US authorities. In prospective, randomized, controlled trails, both agents exhibited a very acceptable safety profile, along with an increase in forced expiratory volume in 1 second and other clinically relevant endpoints. New developments focus on such components as reducing the treatment burden by using dry power inhalers, decreasing inhalation frequency to once daily, penetrating P. aeruginosa biofilms, and combining two antibiotics in one solution for inhalation. However, the ideal aerosolized antibiotic regimen for the treatment of chronic P. aeruginosa infection has yet not been selected.

Tobramycin administered by the TOBI(®) Podhaler(®) for persons with cystic fibrosis: a review

From its introduction, the antibiotic tobramycin has been an important tool in the management of persons with cystic fibrosis (CF) and chronic Pseudomonas aeruginosa lung infections. Initially an intravenous rescue treatment for pulmonary exacerbations, tobramycin delivered by inhalation has become a mainstay of chronic suppressive CF infection management. Platforms for tobramycin aerosol delivery have steadily improved, with increased lung deposition complimented by decreased device complexities, loaded tobramycin doses, delivery times, and treatment burdens. Most recently, a unique tobramycin inhalation powder (TIP) formulation with a portable delivery system, the TOBI^® Podhaler^® (Novartis AG, Basel, Switzerland) has been developed and approved in Europe, Canada, and Chile. Four capsules, each containing 28 mg of TIP are successively pierced and inhaled via the T-326 Dry Powder Inhaler Device (Novartis AG, Basel, Switzerland). No external power source is required to deliver an efficacious tobramycin dose in minutes. By comparison, tobramycin inhalation solution (TIS) (TOBI^®; Novartis), is delivered by LC^® Plus (PARI Respiratory Equipment Inc, Midlothian, VA) jet nebulizer powered by an air compressor over 15–20 minutes. Comparative pharmacokinetics, safety, and efficacy studies of TIS and TIP in CF subjects with P. aeruginosa ≥ 6 years old demonstrate that: tobramycin lung deposition with 112 mg TIP is comparable to that attained with 300 mg TIS, TIP is more effective than placebo and not inferior to TIS with respect to pulmonary function benefit, and TIP has significantly faster treatment times and achieves higher patient satisfaction than TIS. TIP is associated with an increased frequency of mild to moderate local adverse events (cough, dysphonia, and dysgeusia) compared with TIS, however, these become less frequent as subjects gain TIP experience. These results suggest that the TOBI Podhaler may better meet the needs of many CF patients and families by reducing treatment time and complexity and improving patient satisfaction compared with TIS.

Inhaled antibiotics for long-term therapy in cystic fibrosis

BACKGROUND

Inhaled antibiotics are commonly used to treat persistent airway infection that contributes to lung damage in people with cystic fibrosis (CF).

OBJECTIVES

To examine the evidence that inhaled antibiotic treatment in people with CF reduces frequency of exacerbations of infection, and improves lung function, quality of life and survival. To examine adverse effects of inhaled antibiotic treatment.

SEARCH STRATEGY

Trials were identified from the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register.Last search: 31 January 2011.

SELECTION CRITERIA

Trials were selected if inhaled antibiotic treatment was used for at least four weeks in people with CF, treatment allocation was randomised or quasi-randomised, and there was a control group (either placebo, no placebo or another inhaled antibiotic).

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, judged the risk of bias and extracted data from these trials.

MAIN RESULTS

The searches identified 176 citations to 78 trials. Nineteen trials, with 1724 participants, met the inclusion criteria. Adequate meta-analysis was not possible because of the variability of study design and reporting of results. Seventeen trials with 1562 participants compared an inhaled antibiotic with placebo or usual treatment for a duration between 1 and 32 months. Inhaled tobramycin was studied in eight trials. Lung function (measured as forced expired volume in one second) was higher and exacerbations of lung infection (by different measures) were less in the antibiotic-treated group. Resistance to antibiotics increased more in the antibiotic-treated group than in placebo group when results were reported. No auditory or renal impairment was found; analysis showed tinnitus, voice alteration, hemoptysis and cough were more frequent with tobramycin than placebo. One trial, compared tobramycin with colistin in 115 participants, after one month the mean difference in forced expiratory volume at one second was 6.33 (95% confidence interval -0.04 to 12.70) favouring tobramycin.

AUTHORS' CONCLUSIONS

Inhaled antibiotic treatment probably improves lung function and reduces exacerbation rate, but a pooled estimate of the level of benefit is not possible. The best evidence is for inhaled tobramycin. More evidence, from trials of longer duration, is needed to determine whether this benefit is maintained and to determine the significance of development of antibiotic-resistant organisms.

Challenges and advances in the development of inhalable drug formulations for cystic fibrosis lung disease

INTRODUCTION

Cystic fibrosis (CF) is a multisystem genetic disorder, which usually results in significant respiratory dysfunction. At present there is no cure for CF, but advances in pharmacotherapy have gradually increased the life expectancy of CF patients. As many drugs used in the therapy of CF are delivered by inhalation, the demand for effective and convenient inhalational CF drug formulations will grow as CF patients live longer. Knowledge of the current limitations in inhalational CF drug delivery is critical in identifying new opportunities and designing rational delivery strategies.

AREAS COVERED

This review discusses current and emerging therapeutic agents for CF therapy, selected physiological challenges to effective inhalational medication delivery, and various approaches to overcoming these challenges. The reader will find an integrated view of the known inhalational drug delivery challenges and the rationales for recent investigational inhalational drug formulations.

EXPERT OPINION

An ideal drug/gene delivery system to CF airways should overcome the tenacious sputum, which presents physical, chemical and biological barriers to effective transport of therapeutic agents to the targets and various cellular challenges.

Changes in cystic fibrosis sputum microbiology in the United States between 1995 and 2008

STUDY OBJECTIVES

The study objective was to identify changes in cystic fibrosis (CF) sputum microbiology over 13 years.

METHODS

This study recruited a contemporary cohort of CF patients meeting similar eligibility criteria as the 520 subjects in the Phase 3 trials of inhaled tobramycin (historical cohort). Subjects submitted a single sputum specimen to a centralized laboratory for culture and susceptibility testing. Data were summarized and cross-sectional prevalence estimates were compared between cohorts. Exploratory analyses examined associations between recent antibiotic exposures and resistance prevalence.

RESULTS

Sputum samples from 267 subjects from 33 US CF centers were submitted for testing. A total of 656 Pseudomonas aeruginosa isolates were identified from 253 culture-positive subjects. Comparison between cohorts revealed an increase in the prevalence of subjects with tobramycin resistant (11.8% vs. 30.4%, P < 0.001) and amikacin resistant (24.2% vs. 42.7%, P < 0.001) P. aeruginosa. Prevalence of ciprofloxacin resistance was similar (34.4% vs. 33.6%, P = 0.81). Within the contemporary cohort, potential associations between recent antibiotic exposures and prevalence of P. aeruginosa resistance were examined; findings included that exposure to intravenous carbapenems was significantly associated with aztreonam resistance, meropenem resistance, and multidrug resistance (P = 0.0002, P = 0.0003, and P = 0.0002, respectively). Prevalences of Staphylococcus aureus, methicillin-resistant S. aureus, Stenotrophomonas maltophilia, and Achromobacter xylosoxidans were also increased in the contemporary cohort.

CONCLUSIONS

We identified important changes in the patterns of CF airway microbiology, including increased aminoglycoside resistance and prevalence of other antibiotic resistant organisms. These changes are concerning to clinicians caring for individuals with CF because they impact treatment options. These data point to a critical need to develop new antimicrobials for CF.

Inhaled therapeutics for prevention and treatment of pneumonia

The lungs are the most common site of serious infection owing to their large surface area exposed to the external environment and minimum barrier defense. However, this architecture makes the lungs readily available for topical therapy. Therapeutic aerosols include those directed towards improving mucociliary clearance of pathogens, stimulation of innate resistance to microbial infection, cytokine stimulation of immune function and delivery of antibiotics. In our opinion inhaled antimicrobials are underused, especially in patients with difficult-to-treat lung infections. The use of inhaled antimicrobial therapy has become an important part of the treatment of airway infection with Pseudomonas aeruginosa in cystic fibrosis and the prevention of invasive fungal infection in patients undergoing heart and lung transplantation. Cytokine inhaled therapy has also been explored in the treatment of neoplastic and infectious disease. The choice of pulmonary drug delivery systems remains critical as air-jet and ultrasonic nebulizer may deliver sub-optimum drug concentration if not used properly. In future development of this field, we recommend an emphasis on the study of the use of aerosolized hypertonic saline solution to reduce pathogen burden in the airways of subjects infected with microbes of low virulence, stimulation of innate resistance to prevent pneumonia in immunocompromised subjects using cytokines or synthetic pathogen-associated molecular pattern analogues and more opportunities for the use of inhaled antimicrobials. These therapeutics are still in their infancy but show great promise.

Efficacy of aerosol MP-376, a levofloxacin inhalation solution, in models of mouse lung infection due to Pseudomonas aeruginosa

Progressive respiratory failure due to Pseudomonas aeruginosa is the leading cause of morbidity and mortality in patients with cystic fibrosis. The pulmonary delivery of antimicrobial agents provides high concentrations of drug directly to the site of infection and attains pharmacokinetic-pharmacodynamic indices exceeding those which can be achieved with systemic dosing. MP-376 is a new formulation of levofloxacin that enables the safe aerosol delivery of high concentrations of drug to pulmonary tissues. In vivo studies were conducted to demonstrate the efficacy of MP-376 in models of mouse pulmonary infection. The superiority of aerosol dosing over systemic dosing was demonstrated in models of both acute and chronic lung infection. In a model of acute lung infection, aerosol treatment with MP-376 once or twice daily reduced the lung bacterial load to a greater extent than aerosol tobramycin or aztreonam did when they were administered at similar or higher doses. The bacterial killing by aerosol MP-376 observed in the lung in the model of acute pulmonary infection translated to improved survival (P < 0.05). In a model of chronic pulmonary infection, aerosol MP-376 had antimicrobial effects superior to those of aztreonam (P < 0.05) and effects similar to those of tobramycin (P > 0.05). In summary, these data show that aerosol MP-376 has in vivo activity when it is used to treat acute and chronic lung infections caused by P. aeruginosa.

Pulmonary deposition of inhaled tobramycin prior to and after respiratory therapy and use of inhaled albuterol in cystic fibrosis patients colonized with Pseudomonas aeruginosa

OBJECTIVE

To evaluate whether respiratory therapy followed by the use of inhaled albuterol modifies the pulmonary deposition of inhaled tobramycin in patients with cystic fibrosis (CF) and whether pulmonary deposition correlates with disease severity or genotype.

METHODS

A prospective study was carried out including patients with CF older than 6 years of age and colonized with Pseudomonas aeruginosa. Exclusion criteria were pulmonary exacerbation, changes in therapy between the study phases and FEV1 < 25%. All patients were submitted to pulmonary scintigraphy by means of a scintillation camera equipped with a low energy all purpose collimator in order to evaluate drug penetration following the administration of inhaled 99mTc-tobramycin, as well as to pulmonary perfusion with 99mTc-macroaggregated albumin (phase 1). One month later, the same procedure was performed following respiratory therapy and administration of inhaled albuterol (phase 2).

RESULTS

We included 24 patients (12 males) aged 5-27 years (mean +/- SD: 12.85 +/- 6.64 years). The Shwachman score (SS) was excellent/good in 8 patients, moderate/fair in 16 and poor in 0. Genotyping revealed that 7 patients were DeltaF508 homozygotes, 13 were DeltaF508 heterozygotes; and 4 presented other mutations. In all patients, lung deposition of tobramycin decreased in phase 2, especially in those with moderate/fair SS (p = 0.017) and in heterozygotes (p = 0.043).

CONCLUSIONS

The use of a respiratory therapy technique and the administration of inhaled albuterol immediately prior to the use of inhaled tobramycin decreased the pulmonary deposition of the latter in CF patients, and this reduction correlates with disease severity and genotype.

Shifting patterns of inhaled antibiotic use in cystic fibrosis

RATIONALE

Antibiotic inhalation has become widely accepted as a standard treatment for cystic fibrosis (CF) airway infection. We assessed the prevalence and context of inhaled antibiotic use in the North American CF population. Our working hypothesis was that a shift from acute to chronic use of inhaled antibiotics has coincided with increased prevalence of use among CF patients.

METHODS

Descriptive statistics were collected for 30,833 patients enrolled in the Epidemiologic Study of CF (ESCF) during 1996 through 2005. A multivariate analysis was performed on data from a subgroup of 18,021 patients enrolled in ESCF during 2003 through 2005.

RESULTS

The prevalence of inhaled antibiotic use in the North American CF population increased during 1996 through 2005 due to increased chronic use, while acute use to treat pulmonary exacerbations decreased. In 2005, 50% of CF patients used inhaled tobramycin and 9% used inhaled colistin chronically; most of the latter used both agents concurrently. Airway obstruction severity and airway infection status were predictors of inhaled antibiotic use.

CONCLUSIONS

Increased chronic use and decreased acute use of inhaled antibiotics presumably reflect a shift toward more proactive management of airway infections in the North American CF population. The effects of these usage patterns on long-term clinical outcomes and emergence of antibiotic-resistant Pseudomonas aeruginosa strains warrant further study.

Inhaled aztreonam lysine for chronic airway Pseudomonas aeruginosa in cystic fibrosis

RATIONALE

The effectiveness and safety of aztreonam lysine for inhalation (AZLI) in patients with cystic fibrosis (CF) on maintenance treatment for Pseudomonas aeruginosa (PA) airway infection was evaluated in this randomized, double-blind, placebo-controlled study.

OBJECTIVES

To evaluate the safety and efficacy of inhaled aztreonam lysine in controlling PA infection in patients with CF.

METHODS

After randomization and a 28-day course of tobramycin inhalation solution (TIS), patients (n = 211; > or =6 yr; > or =3 TIS courses within previous year; FEV(1) > or = 25% and < or =75% predicted values) were treated with 75 mg AZLI or placebo, twice or three times daily for 28 days, then monitored for 56 days. The primary efficacy endpoint was time to need for additional inhaled or intravenous antipseudomonal antibiotics. Secondary endpoints included changes in respiratory symptoms (CF Questionnaire-Revised [CFQ-R] Respiratory Scale), pulmonary function (FEV(1)), and sputum PA density. Adverse events and minimum inhibitory concentrations of aztreonam for PA were monitored.

MEASUREMENTS AND MAIN RESULTS

AZLI treatment increased median time to need for additional antipseudomonal antibiotics for symptoms of pulmonary exacerbation by 21 days, compared with placebo (AZLI, 92 d; placebo, 71 d; P = 0.007). AZLI improved mean CFQ-R respiratory scores (5.01 points, P = 0.02), FEV(1) (6.3%, P = 0.001), and sputum PA density (-0.66 log(10) cfu/g, P = 0.006) compared with placebo; no AZLI dose-response was observed. Adverse events reported for AZLI and placebo were comparable and consistent with CF lung disease. Susceptibility of PA to aztreonam at baseline and end of therapy were similar.

CONCLUSIONS

AZLI was effective in patients with CF using frequent TIS therapy. AZLI delayed time to need for inhaled or intravenous antipseudomonal antibiotics, improved respiratory symptoms and pulmonary function, and was well tolerated. Clinical trial registered with www.clinicaltrials.gov (NCT 00104520).

Microparticles for inhalational delivery of antipseudomonal antibiotics

Chronic pseudomonal bronchopulmonary infections in cystic fibrosis patients are frequently controlled with inhaled antibiotics. Dry-powder inhalable antibiotics are an attractive alternative to nebulized medications. We produced and evaluated microparticles composed of dipalmitoylphosphatidylcholine, albumin, and lactose as a model system for intrapulmonary delivery of ceftazidime, ciprofloxacin, and several combinations of the two, none of which is presently available for inhalation. Microparticles containing one or both antibiotics were prepared by spray-drying. Their Anderson cascade impactor deposition profiles showed 10-30% fine particle fractions of the nominal dose. Microparticles containing varying amounts of each antibiotic showed statistically different deposition profiles. Aerodynamics and deposition of microparticles co-encapsulating both antibiotics were similar to those of single-drug microparticles with the same proportion of ciprofloxacin alone. The antipseudomonal activities of microparticles co-encapsulating half of the 50% effective concentration (EC(50)) of both ceftazidime and ciprofloxacin (5 mg of particles containing 5% ceftazidime and 10% ciprofloxacin) were at least additive compared to particles containing the EC(50) of each antibiotic separately (5 mg of particles containing 10% ceftazidime or 5 mg of particles containing 20% ciprofloxacin). Co-encapsulation of the antibiotics in microparticles ensures co-deposition at desired ratios, improves the particles' aerodynamics and fine particle fraction, as compared to microparticles with equivalent amounts of ceftazidime alone, and achieves additive antipseudomonal activity.

A phase 2 study of aztreonam lysine for inhalation to treat patients with cystic fibrosis and Pseudomonas aeruginosa infection

BACKGROUND

Aztreonam lysine for inhalation (AZLI) is being developed for treatment of CF patients with Pseudomonas aeruginosa airway infection.

METHODS

This double-blind, randomized, placebo-controlled Phase 2 study evaluated the safety, tolerability and efficacy of 75 and 225 mg AZLI administered BID for 14 days using the eFlow Electronic Nebulizer (Pari Innovative Manufacturers, Inc., Midlothian, VA). Patients were 13 years and older with FEV1>or=40% predicted, chronic P. aeruginosa infection, and had used no anti-pseudomonal antibiotics for 56 days.

RESULTS

Of 131 patients screened, 105 received AZLI or placebo. Mean age was 26 years and mean FEV1 percent predicted was 77% at baseline. There was a statistically significant reduction, compared to placebo, in P. aeruginosa CFU density in each AZLI group at Days 7 and 14 (P<0.001). The planned primary analysis, percent change in FEV1 at Day 14, demonstrated no statistically significant difference. Post hoc analysis demonstrated significant increase in FEV1 at Day 7 for the subset of patients with baseline FEV1<75% predicted in the 225 mg AZLI group. Bronchodilator use was associated with greater improvement in FEV1, as well as greater reduction in P. aeruginosa bacterial density and higher plasma aztreonam concentrations in the 225 mg AZLI group. Adverse events were similar between placebo and AZLI although there was a trend toward increased respiratory symptoms in the 225 mg AZLI group.

CONCLUSION

These data support the further development of AZLI and provide information for the design of subsequent studies.

Use of lung imaging studies as outcome measures for development of new therapies in cystic fibrosis

Most cystic fibrosis (CF) drug development has been based upon functional outcomes (e.g., FEV(1)) rather than structural changes. This functional approach has the limitation of being insensitive of early changes in lung disease. Computer tomography (CT) scanning affords the opportunity to establish a new paradigm to stage the illness (and target populations) based upon morphology. Using this concept, treatment regimens would be tested to prevent progression, reverse early changes, or stabilize established structural damage. In this setting, imaging biomarkers could play a key role. This article reviews the potential uses of CT scanning in the different phases of drug development (phase 1 to 4 studies). In early-phase studies (i.e., human pharmacology and therapeutic exploratory trials), CT could be used to provide preliminary data on mechanisms of action and efficacy. For large phase 3, therapeutic, confirmatory trials, CT scans are less likely to be the primary endpoint, but may play a supportive role in clinical efficacy measures and subset analyses (e.g., infants). For postmarketing therapeutic use trials, CT scans could play an important role in defining long-term efficacy in subpopulations, such as infants and children. Further steps need to be taken to optimize imaging biomarkers. These steps include establishing standard procedures across multiple research sites, centralized reading centers, and a common scoring system. To validate optimal CT parameter(s), the CF community must continue to collect CT data in phase 1 and 2 trials documenting response to therapeutic intervention. In addition, there is a need for additional longitudinal epidemiology studies to establish the association of CT changes with other outcome measures, such as pulmonary function tests, quality of life measures, and mortality.

Cystic fibrosis pulmonary guidelines: chronic medications for maintenance of lung health

RATIONALE

Cystic fibrosis is a recessive genetic disease characterized by dehydration of the airway surface liquid and impaired mucociliary clearance. As a result, individuals with the disease have difficulty clearing pathogens from the lung and experience chronic pulmonary infections and inflammation. Death is usually a result of respiratory failure. Newly introduced therapies and aggressive management of the lung disease have resulted in great improvements in length and quality of life, with the result that the median expected survival age has reached 36 years. However, as the number of treatments expands, the medical regimen becomes increasingly burdensome in time, money, and health resources. Hence, it is important that treatments should be recommended on the basis of available evidence of efficacy and safety.

OBJECTIVES

The Cystic Fibrosis Foundation therefore established a committee to examine the clinical evidence for each therapy and to provide guidance for the prescription of these therapies.

METHODS

The committee members developed and refined a series of questions related to drug therapies used in the maintenance of pulmonary function. We addressed the questions in one of three ways, based on available evidence: (1) commissioned systematic review, (2) modified systematic review, or (3) summary of existing Cochrane reviews.

CONCLUSIONS

It is hoped that the guidelines provided in this article will facilitate the appropriate application of these treatments to improve and extend the lives of all individuals with cystic fibrosis.

Incidence and risk factors for multiple antibiotic-resistant Pseudomonas aeruginosa in cystic fibrosis

BACKGROUND

Infection with multiple antibiotic-resistant Pseudomonas aeruginosa (MARPA) in individuals with cystic fibrosis (CF) has caused much concern among caregivers, yet little is known about the risks associated with acquiring resistance. The main objective of the study was to estimate the incidence and identify risk factors for the acquisition of MARPA among individuals with CF.

METHODS

Five-year cohort study of individuals followed in the Cystic Fibrosis Foundation Registry from 1998 through 2002.

RESULTS

Demographics, anthropometrics, spirometry, respiratory culture results, comorbidities, antibiotic usage, and hospitalizations were collected. Of the 4,293 patients with P aeruginosa infection during the study period, MARPA developed in 341. The overall incidence of MARPA was 1.8%/yr. Independent risk factors for MARPA included CF-related diabetes mellitus (hazard ratio [HR], 1.64; 95% confidence interval [CI], 1.11 to 2.43), long-term inhaled tobramycin usage (HR, 2.08; 95% CI, 1.56 to 2.77), and care at a CF center with a baseline MARPA prevalence in the top quartile (HR, 2.00; 95% CI, 1.31 to 3.04). Frequent courses of IV antibiotics and repeated hospitalizations were also found to independently increase the risk for MARPA.

CONCLUSIONS

Infection with MARPA is common among patients with CF. Diabetes, long-term inhaled tobramycin usage, and frequent acute pulmonary exacerbations requiring hospitalization or IV antibiotics increase the risk for MARPA. Receiving CF care at a center with a high prevalence of resistant Pseudomonas also increases the risk for MARPA in patients with CF. Further study is needed to investigate the mechanisms of acquiring resistant strains and the clinical impact of MARPA on CF outcomes.

Approaches to the Treatment of Initial Pseudomonas aeruginosa Infection in Children Who Have Cystic Fibrosis

Pseudomonas aeruginosa remains an important cause of pulmonary disease in patients who have cystic fibrosis. The development of antimicrobial therapy directed against this organism has resulted in the preservation of lung function and improved longevity. Efficacy has been demonstrated with agents administered via parenteral, inhaled, and oral routes. The optimal antibiotic regimen remains unclear. There is an active effort to use randomized, controlled clinical trials to rigorously test effective antibiotic for the eradication of P aeruginosa in young children or at least to delay the establishment of chronic infection.

Tobramycin solution for inhalation in cystic fibrosis patients: a review of the literature

Cystic fibrosis patients suffer increased sputum production and a notable decline in respiratory function throughout the progression of their disease. Patients are left vulnerable to respiratory colonization/infection from a number of pathogens, including Pseudomonas aeruginosa. At present, the only antibiotic formulation that is FDA approved for aerosolized delivery is tobramycin solution for inhalation (TSI). TSI allows for targeted antibiotic delivery to the lungs and is indicated for maintenance therapy in cystic fibrosis patients infected with P. aeruginosa. Studies demonstrate that cyclical treatment with TSI is associated with an increase in respiratory function and a decrease in sputum density in cystic fibrosis patients. Additional benefits include fewer hospitalizations and a decreased need for systemic antibiotics. However, because of the need for chronic administration, issues such as emergence of resistant organisms and toxicity are a potential concern and have also been evaluated. This review details the pharmacology of TSI and literature involving its use in cystic fibrosis patients.