Dornase alfa in the treatment of cystic fibrosis in Europe: a report from the Epidemiologic Registry of Cystic Fibrosis

Brazilian guidelines for the pharmacological treatment of the pulmonary symptoms of cystic fibrosis. Official document of the Sociedade Brasileira de Pneumologia e Tisiologia (SBPT, Brazilian Thoracic Association)

Cystic fibrosis (CF) is a genetic disease that results in dysfunction of the CF transmembrane conductance regulator (CFTR) protein, which is a chloride and bicarbonate channel expressed in the apical portion of epithelial cells of various organs. Dysfunction of that protein results in diverse clinical manifestations, primarily involving the respiratory and gastrointestinal systems, impairing quality of life and reducing life expectancy. Although CF is still an incurable pathology, the therapeutic and prognostic perspectives are now totally different and much more favorable. The purpose of these guidelines is to define evidence-based recommendations regarding the use of pharmacological agents in the treatment of the pulmonary symptoms of CF in Brazil. Questions in the Patients of interest, Intervention to be studied, Comparison of interventions, and Outcome of interest (PICO) format were employed to address aspects related to the use of modulators of this protein (ivacaftor, lumacaftor+ivacaftor, and tezacaftor+ivacaftor), use of dornase alfa, eradication therapy and chronic suppression of Pseudomonas aeruginosa, and eradication of methicillin-resistant Staphylococcus aureus and Burkholderia cepacia complex. To formulate the PICO questions, a group of Brazilian specialists was assembled and a systematic review was carried out on the themes, with meta-analysis when applicable. The results obtained were analyzed in terms of the strength of the evidence compiled, the recommendations being devised by employing the GRADE approach. We believe that these guidelines represent a major advance to be incorporated into the approach to patients with CF, mainly aiming to favor the management of the disease, and could become an auxiliary tool in the definition of public policies related to CF.

The Fatal Circle of NETs and NET-Associated DAMPs Contributing to Organ Dysfunction

The innate immune system is the first line of defense against invading pathogens or sterile injuries. Pattern recognition receptors (PRR) sense molecules released from inflamed or damaged cells, or foreign molecules resulting from invading pathogens. PRRs can in turn induce inflammatory responses, comprising the generation of cytokines or chemokines, which further induce immune cell recruitment. Neutrophils represent an essential factor in the early immune response and fulfill numerous tasks to fight infection or heal injuries. The release of neutrophil extracellular traps (NETs) is part of it and was originally attributed to the capture and elimination of pathogens. In the last decade studies revealed a detrimental role of NETs during several diseases, often correlated with an exaggerated immune response. Overwhelming inflammation in single organs can induce remote organ damage, thereby further perpetuating release of inflammatory molecules. Here, we review recent findings regarding damage-associated molecular patterns (DAMPs) which are able to induce NET formation, as well as NET components known to act as DAMPs, generating a putative fatal circle of inflammation contributing to organ damage and sequentially occurring remote organ injury.

A Fragile Balance: Does Neutrophil Extracellular Trap Formation Drive Pulmonary Disease Progression?

Neutrophils act as the first line of defense during infection and inflammation. Once activated, they are able to fulfil numerous tasks to fight inflammatory insults while keeping a balanced immune response. Besides well-known functions, such as phagocytosis and degranulation, neutrophils are also able to release "neutrophil extracellular traps" (NETs). In response to most stimuli, the neutrophils release decondensed chromatin in a NADPH oxidase-dependent manner decorated with histones and granule proteins, such as neutrophil elastase, myeloperoxidase, and cathelicidins. Although primarily supposed to prevent microbial dissemination and fight infections, there is increasing evidence that an overwhelming NET response correlates with poor outcome in many diseases. Lung-related diseases especially, such as bacterial pneumonia, cystic fibrosis, chronic obstructive pulmonary disease, aspergillosis, influenza, and COVID-19, are often affected by massive NET formation. Highly vascularized areas as in the lung are susceptible to immunothrombotic events promoted by chromatin fibers. Keeping this fragile equilibrium seems to be the key for an appropriate immune response. Therapies targeting dysregulated NET formation might positively influence many disease progressions. This review highlights recent findings on the pathophysiological influence of NET formation in different bacterial, viral, and non-infectious lung diseases and summarizes medical treatment strategies.

Aerosol Delivery of Dornase Alfa Generated by Jet and Mesh Nebulizers

Recent reports on mesh nebulizers suggest the possibility of stable nebulization of various therapeutic protein drugs. In this study, the in vitro performance and drug stability of jet and mesh nebulizers were examined for dornase alfa and compared with respect to their lung delivery efficiency in BALB/c mice. We compared four nebulizers: two jet nebulizers (PARI BOY SX with red and blue nozzles), a static mesh nebulizer (NE-U150), and a vibrating mesh nebulizer (NE-SM1). The enzymatic activity of dornase alfa was assessed using a kinetic fluorometric DNase activity assay. Both jet nebulizers had large residual volumes between 24% and 27%, while the volume of the NE-SM1 nebulizer was less than 2%. Evaluation of dornase alfa aerosols produced by the four nebulizers showed no overall loss of enzymatic activity or protein content and no increase in aggregation or degradation. The amount of dornase alfa delivered to the lungs was highest for the PARI BOY SX-red jet nebulizer. This result confirmed that aerosol droplet size is an important factor in determining the efficiency of dornase alfa delivery to the lungs. Further clinical studies and analysis are required before any conclusions can be drawn regarding the clinical safety and efficacy of these nebulizers.

Aerosolized agents for airway clearance in cystic fibrosis

The outlook for people with cystic fibrosis (CF) has improved considerably as a result of conventional therapies including aerosolized agents for airway clearance. These will continue to play a significant role in maintaining well-being and improving survival, even as newer agents emerge that correct the underlying CF defect. In this review, we explore the evidence supporting the use of dornase alfa, hypertonic saline, and mannitol in improving mucus clearance in patients with CF from different age groups with differing disease severity. We also discuss the clinical use of these agents in the context of available international guidelines as well as practical considerations in the clinic, highlighting the importance of a multidisciplinary approach and shared decision-making. Unanswered questions regarding the optimal use of these agents are highlighted.

The epithelial sodium channel (ENaC) as a therapeutic target for cystic fibrosis lung disease

INTRODUCTION

Cystic fibrosis is an autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that codes for the CFTR anion channel. In the absence of functional CFTR, the epithelial Na⁺ channel is also dysregulated. Airway surface liquid (ASL) hydration is maintained by a balance between epithelial sodium channel (ENaC)-led Na⁺ absorption and CFTR-dependent anion secretion. This finely tuned homeostatic mechanism is required to maintain sufficient airway hydration to permit the efficient mucus clearance necessary for a sterile lung environment. In CF airways, the lack of CFTR and increased ENaC activity lead to ASL/mucus dehydration that causes mucus obstruction, neutrophilic infiltration, and chronic bacterial infection. Rehydration of ASL/mucus in CF airways can be achieved by inhibiting Na⁺ absorption with pharmacological inhibitors of ENaC. Areas covered: In this review, we discuss ENaC structure and function and its role in CF lung disease and focus on ENaC inhibition as a potential therapeutic target to rehydrate CF mucus. We also discuss the failure of the first generation of pharmacological inhibitors of ENaC and recent alternate strategies to attenuate ENaC activity in the CF lung. Expert opinion: ENaC is an attractive therapeutic target to rehydrate CF ASL that may serve as a monotherapy or function in parallel with other treatments. Given the increased number of strategies being employed to inhibit ENaC, this is an exciting and optimistic time to be in this field.

Recombinant human deoxyribonuclease therapy improves airway resistance and reduces DNA extracellular traps in a murine acute asthma model

PURPOSE

Asthma is a highly prevalent chronic inflammatory lung disease characterized by airway hyperresponsiveness to allergens, airway edema, and increased mucus secretion. Such mucus can be liquefied by recombinant human deoxyribonuclease (rhDNase), in which efficacy of rhDNase has been well documented in patients with cystic fibrosis, but little studied in asthma. In the present study, we investigated whether rhDNase intranasal administration improved inflammation and pulmonary function in an experimental model of asthma.

METHODS

Mice were sensitized by two subcutaneous injections of ovalbumin (OVA), on days 0 and 7, followed by three intranasal challenges with OVA on days 14, 15, and 16. A control group, replacing OVA by DPBS, was included. On days 15 and 16, after 2 hours of OVA challenge, mice received 1 mg/mL of intranasal rhDNase.

RESULTS

We showed that rhDNase decreased significantly the airway resistance and reduced EETs formation and globet cells hyperplasia.

CONCLUSIONS

Our results suggest that extracellular DNA in mucus play a role in lower airways obstruction in OVA asthma protocol and that the treatment with rhDNase improved lung function and DNA extracellular traps, with no direct cellular anti-inflammatory effects.

Clinical Practice Guidelines From the Cystic Fibrosis Foundation for Preschoolers With Cystic Fibrosis

Cystic fibrosis (CF) clinical care guidelines exist for the care of infants up to age 2 years and for individuals ≥6 years of age. An important gap exists for preschool children between the ages of 2 and 5 years. This period marks a time of growth and development that is critical to achieve optimal nutritional status and maintain lung health. Given that disease often progresses in a clinically silent manner, objective and sensitive tools that detect and track early disease are important in this age group. Several challenges exist that may impede the delivery of care for these children, including adherence to therapies. A multidisciplinary committee was convened by the CF Foundation to develop comprehensive evidence-based and consensus recommendations for the care of preschool children, ages 2 to 5 years, with CF. This document includes recommendations in the following areas: routine surveillance for pulmonary disease, therapeutics, and nutritional and gastrointestinal care.

[Inhalation therapy: provocation tests, infectious risks, acute bronchiolitis and ENT diseases. GAT aerosolstorming, Paris 2011]

Communications from the 2011 meeting of the GAT are reported in this second article on the practical management of bronchial provocation tests and infectious risks associated with the use of nebulization. Recent advances on the role of nebulized hypertonic saline in the treatment of acute bronchiolitis in infants and of the nebulization in sinusal diseases are also reported.

Reduced mortality in cystic fibrosis patients treated with tobramycin inhalation solution

BACKGROUND

Though tobramycin inhalation solution has been used for over a decade to improve lung function and reduce exacerbations in patients with cystic fibrosis (CF), its effects on mortality have not been well-described. This study aimed to assess the association between use of tobramycin inhaled solution and mortality in patients with CF and chronic Pseudomonas aeruginosa (PA) infection.

METHODS

Longitudinal logistic regression was used to assess the association between current-year reported use of tobramycin inhalation solution and subsequent-year mortality of patients meeting recommended criteria for tobramycin inhalation solution use in the United States Cystic Fibrosis Foundation's Patient Registry (1996-2008).

RESULTS

Among 12,740 patients meeting inclusion criteria, 2,538 deaths were observed during a median follow-up of 6 years. After regression adjustment, use of tobramycin inhaled solution was associated with a 21% reduction in the odds of subsequent year mortality (odds ratio (95% CI): 0.79 (0.72-0.88), P < 0.001). In our model, use of dornase alfa was also associated with a 15% reduction in the odds of subsequent year mortality (odds ratio (95% CI): 0.85 (0.76-0.95), P = 0.005). Underweight for age, CF-related diabetes, female gender, worse lung function and cultures positive for Pseudomonas aeruginosa or Burkholderia cepacia complex, among multiple other patient characteristics, were associated with significantly increased mortality. Adjusted mortality rates for patients reporting tobramycin inhalation solution use in all versus none of the follow-up years were 1.3% versus 2.1% at 2 years, 5.2% versus 8.0% at 5 years, and 9.9% versus 15.0% at 10 years.

CONCLUSION

After adjustment for multiple patient characteristics and known risk factors, use of tobramycin inhalation solution was associated with significantly reduced mortality among patients with CF.

Review of recombinant human deoxyribonuclease (rhDNase) in the management of patients with cystic fibrosis

The most important problem in cystic fibrosis (CF) lung disease is chronic airway inflammation and infection, which starts early in life. To prevent severe lung damage, it is important to mobilize as much sputum as possible from the lung on a daily basis. RhDNase is an enzyme that breaks down DNA strands in airway secretions, hydrolyzes the DNA present in sputum/mucus of CF patients, reducing viscosity in the lungs and promoting secretion clearance. Several well performed trials have proven its efficacy in young CF patients with mild disease as well as in older patients with more advanced lung disease. Daily inhalation of this agent slows down lung function decline and decreases the frequency of respiratory exacerbations. The drug is well tolerated by most patients independent of the severity of lung disease.

An overview of international literature from cystic fibrosis registries. Part 3. Disease incidence, genotype/phenotype correlation, microbiology, pregnancy, clinical complications, lung transplantation, and miscellanea

This is the third article related to a review of the literature based on data from national cystic fibrosis (CF) patient registries up to June 2008 and covering a total of 115 published studies. It focuses on several topics: CF incidence, genotype/phenotype correlation, microbiology, pregnancy/paternity, clinical complications, lung transplantation, and others. Seventy seven papers meeting the inclusion criteria were found to be related to the topics listed above. Another seven studies, already evaluated in previous papers of this series, were recalled for specific topics. Incidence is described by several studies, results being quite different from one country to another and quite inhomogeneous among regions within the same country. Studies on genetics address the genotype/phenotype correlation and look for a predictive value of CFTR mutations in terms of clinical outcome, with controversial results. Papers on microbiology describe the clinical relevance of different pathogens and their role in the progress of CF lung disease. A few articles give information on the features of CF women undergoing a pregnancy and try to identify the ones associated with a better outcome. Studies on clinical complications discuss prevalence and the role of haemoptysis, pneumothorax, CF related diabetes, ABPA and cancer. Papers on lung transplantation focus on models able to improve the selection criteria for transplantation candidates and the factors linked to post transplantation survival. Finally, several studies deal with a number of interesting topics related to CF epidemiology: clinical trial methodology, quality of care comparison among countries and centers, relationship between diagnosis and age/gender, and evaluation of pharmacological therapy. On the whole, CF Registries have already contributed to important advances in the knowledge of the natural history of CF, establishing the foundations for future improvement in CF research and care.

Mannitol-guided delivery of Ciprofloxacin in artificial cystic fibrosis mucus model

Abnormal airway mucus presents a significant challenge for inhalational drug delivery. Recognizing the thick and tenacious airway mucus seen in the cystic fibrosis (CF) patients as a critical barrier to effective drug delivery, both into the mucus layer itself as well as across that layer to the underlying airway epithelium, we hypothesize that mannitol or NaCl can form inhalable drug carriers, improve drug penetration into the mucus, and ultimately enhance the drug's therapeutic effect. The objective of this study is to test whether mannitol and NaCl particles, as inhalable drug carriers, improve drug delivery into and enhance a drug's activity within a mucus-like material. Microparticles containing Ciprofloxacin (Cipro), an active ingredient, and either mannitol or NaCl were produced by spray-drying. Cipro encapsulated in mannitol particles (Cipro-mannitol) was significantly more effective at killing Pseudomonas aeruginosa (P. aeruginosa) grown in artificial mucus (AM) than Cipro encapsulated in either NaCl particles (Cipro-NaCl) or in hydrophobic particles consisting of dipalmitoylphosphatidylcholine (DPPC), albumin, and lactose (Cipro-DAL). The relatively high antibacterial effectiveness of Cipro-mannitol was not due to the effect of mannitol on bacteria or on Cipro. Rather, the unique performance of the mannitol-based particles in AM is attributable to its ability to increase local water content in the AM and enhance drug penetration into it. Mannitol is a promising excipient for inhalable microparticles that facilitate the drug delivery into the CF mucus.

Pharmacology, clinical efficacy and safety of recombinant human DNase in cystic fibrosis

Recombinant human DNase (rhDNase) is a mucolytic agent that is primarily used to improve mucociliary clearance in cystic fibrosis (CF). rhDNase is a recombinant human enzyme that is synthesized in a Chinese hamster ovary cell line. rhDNase enzymatically cleaves extracellular DNA into molecules of shorter length. CF sputum shows high concentrations of DNA released by disintegrating inflammatory cells. Free DNA contributes to the abnormally high viscosity of CF sputum and therefore forms an important target in the treatment of CF lung disease. Clinical studies have shown that daily nebulization of rhDNase is associated with an increase in lung function and a decrease in the frequency of exacerbations in patients with CF.

Interference of Pseudomonas aeruginosa signalling and biofilm formation for infection control

Pseudomonas aeruginosa is the best described bacterium with regards to quorum sensing (QS), in vitro biofilm formation and the development of antibiotic tolerance. Biofilms composed of P. aeruginosa are thought to be the underlying cause of many chronic infections, including those in wounds and in the lungs of patients with cystic fibrosis. In this review, we provide an overview of the molecular mechanisms involved in QS, QS-enabled virulence, biofilm formation and biofilm-enabled antibiotic tolerance. We now have substantial knowledge of the multicellular behaviour of P. aeruginosa in vitro. A major task for the future is to investigate how such in vitro data correlate with the in vivo behaviour of P. aeruginosa, and how to treat chronic infections of this bacterium in patients.

Emerging treatments in cystic fibrosis

There are a number of potential drugs for the treatment of cystic fibrosis (CF) currently undergoing clinical studies. A number of antibacterials formulated for delivery by inhalation are at various stages of study; these include dry-powder inhaler versions of colistin, tobramycin and ciprofloxacin, and formulations of azteonam, amikacin, levofloxacin, ciprofloxacin and fosfomycin/tobramycin for nebulization. Clinical trials of anti-inflammatory agents, including glutathione, phosphodiesterase-5 inhibitors such as sildenafil, oral acetylcysteine, simvastatin, methotrexate, docosahexaenoic acid, hydroxychloroquine, pioglitazone and alpha1-antitrypsin, are ongoing. Ion channel modulating agents, such as lancovutide (Moli1901, duramycin) and denufosol, which activate alternate (non-CF transmembrane regulator [CFTR]) chloride channels, and GS 9411, a sodium channel antagonist, are now at the stages of clinical study and if successful, will offer a new category of therapeutic agent for the treatment of CF. Correction of the underlying gene effect, either by agents that help to correct the dysfunctional CFTR, such as ataluren, VX-770 and VX-809, or by gene transfer (gene therapy), is a particularly exciting prospect as a new therapy for CF and clinical studies are ongoing. This article reviews the exciting potential drug treatments for CF currently being evaluated in clinical studies, and also highlights some of the challenges faced by research and clinical teams in assessing the efficacy of potential new therapies for CF.

Association between practice patterns and body mass index percentile in infants and young children with cystic fibrosis

BACKGROUND

Few guidelines focus on the preventive and maintenance care of infants with cystic fibrosis (CF). We explored how practice variability at accredited CF centers affected nutritional outcomes.

METHODS

A retrospective cohort study using Cystic Fibrosis Foundation registry data (1993-2004) from three CF centers compared the initial management with respiratory, antimicrobial, and nutritional agents in infants. Further, we examined the association between dornase alpha use prior to two years of age and BMI percentile over time accounting for several possible factors including gender, race, CF center, presentation, age at diagnosis, sweat value, F508del status, first Pseudomonas aeruginosa infection age, second-year weight percentile, supplemental feedings use, and pancreatic enzymes use.

RESULTS

Patient characteristics and prescribed therapies were similar at all sites for 165 patients who met inclusion criteria. However, one CF center prescribed dornase alpha significantly more frequently, 82% vs. 10% (p<0.001), and supplemental feeds significantly less frequently, 56% vs. 78% (p=0.04). Dornase alpha prescription prior to age two was associated with a 10-percentile increase in BMI through age six compared to infants not prescribed dornase alpha.

CONCLUSIONS

Treating infants less than two years old with dornase alpha may improve nutritional outcome through age six.

Dornase alfa is well tolerated: data from the epidemiologic registry of cystic fibrosis

After closure of the Epidemiologic Registry of Cystic Fibrosis (ERCF), a comprehensive safety analysis of dornase alfa was performed. A planned subanalysis focused on children under 5 years old. Reported serious adverse events (SAEs) were assigned a preferred term and ascribed to a specific organ system. Possible serious adverse reactions to dornase alfa (SADRs) were identified by reporting clinics. Twenty-eight of 15,865 SAEs (0.18%), occurring in 26 of 6,829 patients ever treated with dornase alfa (0.38%), and no deaths were reported as possible SADRs: most were typical complications of cystic fibrosis (CF). There was no evidence of any unrecognized risk of treatment. During 24,586 patient-years of follow-up (FU) of ever-treated patients, SAEs (mostly typical respiratory complications of CF) were more frequent on-treatment (0.4999/patient-year; 95% CI 0.4921-0.5076) than off-treatment (0.3889; 0.3787-0.3992). This was likely caused by within-patient prescription bias. During 655 patient-years of FU in 328 ever-treated patients under 5 years old, SAEs (mostly pulmonary exacerbations of CF) were slightly less frequent during treatment: 0.2911 (0.2367-0.3455) versus 0.3563 (0.3086-0.4040; ns). Results confirm the safety of dornase alfa in CF patients of all ages. Children under 5 years old tolerate dornase alfa at least as well as older patients.

RhDNase before airway clearance therapy improves airway patency in children with CF

INTRODUCTION

Little is known about the optimal timing of rhDNase nebulization in relation to airway clearance therapy (ACT).

OBJECTIVE

To compare the effects of rhDNase before ACT versus rhDNase after ACT in children with CF.

DESIGN

randomized, double blind, double dummy, cross over study.

INCLUSION CRITERIA

CF, stable clinical condition, rhDNase maintenance therapy. Children in Group I inhaled rhDNase 30 minutes before ACT, and placebo directly after ACT in week 1-3. The protocol was reversed during week 4-6. Group II performed the reversed sequence. Patients continued their daily routine ACT. Primary endpoint: MEF(25) %pred. Pulmonary functions tests were performed on days 0, 14, 21, 35 and 42. In weeks 3 and 6 children scored cough and sputum production on daily diary cards.

RESULTS

24 patients completed the study. Mean age = 12 years (range 7-19). Mean MEF(25) %pred was 5.8% higher after 3 weeks of rhDNase before ACT, compared to rhDNase after ACT (58.3% vs 52.5%, p=0.01). There were no significant differences for any of the other variables.

CONCLUSION

Inhalation of rhDNase before ACT improves peripheral airway patency in children with cystic fibrosis. Since all children were already on maintenance rhDNase therapy before the study, this effect is additional to any existing effect of regular rhDNase.

Long-term use of nebulized human recombinant DNase1 in two siblings with primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is characterized by ultra-structural defects of the cilia. In this report, we describe the long-term use of nebulized dornase alfa in two siblings with PCD. This is the first report of long-term use of dornase alfa in PCD.

Nonclassical pathway of Pseudomonas aeruginosa DNA-induced interleukin-8 secretion in cystic fibrosis airway epithelial cells

Pseudomonas aeruginosa is a critical colonizer of the respiratory tract in cystic fibrosis. The chronic infections with this microorganism contribute to excessive inflammation and progressive lung damage in cystic fibrosis patients. The full repertoire of Pseudomonas products that promote inflammation in the cystic fibrosis lung is not known. Here we show that P. aeruginosa DNA released from the bacterium, but not human DNA from epithelial cells or Escherichia coli DNA, displays proinflammatory properties and induces human respiratory epithelial cells to secrete interleukin-8 (IL-8), a key chemokine causing excessive neutrophil infiltration in the cystic fibrosis lung. IL-8 secretion was not due to an increase in NF-kappaB- or activator protein-1-dependent IL-8 promoter transcription, but instead depended on p38 and Erk mitogen-activated protein kinases. No secretion of IL-8 was observed using conventional Toll-like receptor 9 ligands (CpG oligonucleotides), although it could be demonstrated that parts of the Toll-like receptor 9-signaling pathway were functional, since class B and C CpG oligonucleotide ligands stimulated production of RANTES chemokine. The IL-8 secretion in response to P. aeruginosa DNA was decreased by treatments that inhibit acidification of intracellular organelles, using chloroquine, a pH-neutralizing compound, or bafilomycin A1, an inhibitor of vacuolar H+-ATPase. These data indicate that DNA released from P. aeruginosa during chronic infections may significantly contribute to the proinflammatory processes in cystic fibrosis. Our findings also show that treatments with drugs diminishing organellar acidification may reduce the inflammatory response in cystic fibrosis.

Outcome of assisted ventilation for acute respiratory failure in cystic fibrosis

OBJECTIVES

To assess outcome of assisted ventilation in cystic fibrosis (CF) patients with acute respiratory failure (ARF), to identify risk factors associated with poor outcome and to compare long-term outcome of CF children who were mechanically ventilated for ARF with unventilated CF controls.

DESIGN

Retrospective cohort study.

SETTING

Two large CF centres in the Netherlands.

PATIENTS

CF patients who required assisted ventilation for ARF and unventilated CF controls.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Thirty-one CF patients required assisted ventilation for ARF between January 1990 and March 2005. All five children (under 2 years of age) and seven adults (27%) survived. In the total population, age was a statistically significant risk factor for poor outcome (p=0.02). In adult CF patients who required invasive mechanical ventilation, acute on chronic respiratory failure was associated with poor outcome. In children who required mechanical ventilation for ARF, lung function and CF related complications 5 years later were not significantly different compared with controls matched for age, gender and genotype.

CONCLUSIONS

CF patients younger than 2 years old, who are ventilated because of ARF, have a good prognosis and their long-term outcome seems identical to unventilated CF controls. ARF in adult CF patients still is associated with high mortality, especially among patients with acute on chronic respiratory failure.

A crossover, randomized, controlled trial of dornase alfa before versus after physiotherapy in cystic fibrosis

OBJECTIVE

Although dornase alfa is a widely used, aerosolized, mucolytic agent in patients with cystic fibrosis (CF), its efficacy in relation to the timing of physiotherapy has not been tested. We sought to determine whether dornase alfa is more efficacious when it is administered 30 minutes before versus 30 minutes after physiotherapy/positive expiratory pressure (PEP) therapy in clinically stable children.

METHODS

Using a crossover, randomized, double-blind, and placebo-controlled trial, we undertook a 6-week study of the efficacy of dornase alfa in relation to the timing of physiotherapy at home. There were 2 treatment orders. Dornase alfa before + placebo after physiotherapy/PEP for 2 weeks was followed by a 2-week washout and then the reverse order placebo before and dornase alfa after physiotherapy/PEP for the final 2 weeks. The second treatment order reversed the placebo and dornase alfa therapy for the first and last 2-week blocks. The main outcome measures used included the change in predicted percentage of forced expiratory volume in 1 second (FEV1), a composite quality of well-being score (QWB), and a measure of aerobic fitness (maximal oxygen consumption, [VO2max]), determined using shuttle testing.

RESULTS

Fifty-two patients who had CF (27 female) with mild to moderate suppurative lung disease, were a mean +/- SD age of 10.7 +/- 3.2 years, had Shwachman scores of 86 +/- 11.8, had predicted FEV1 of 83% +/- 18%, had quality of well-being score of 0.76 +/- 0.08, and had VO2max of 42.6 +/- 6.3 ml/kg per min were enrolled. Fifty patients completed the study. Intention-to-treat analysis was used. Nonsignificant mean (95% confidence interval) differences in FEV1 (0.02 L [-0.05 to 0.10]), VO2max (-0.75 ml/kg per min [-1.85 to 0.35]), and QWB (0.005 [-0.94 to 0.0028]) for dornase alfa after physiotherapy/PEP were detected. A post hoc analysis showed that patients who were colonized persistently with Pseudomonas aeruginosa had a significantly greater improvement in FEV1 (0.12 L [0.23 to 0.01] vs -0.04 L [0.05 to -0.13]) when dornase alfa was administered after physiotherapy/PEP.

CONCLUSIONS

Dornase alfa is equally efficacious when delivered before or after physiotherapy/PEP in patients with CF. Patients who are colonized persistently with P aeruginosa may derive more improvement in FEV1 when dornase alfa is delivered after physiotherapy/PEP.

The use of human deoxyribonuclease (rhDNase) in the management of cystic fibrosis

In patients with cystic fibrosis (CF), the poor clearance of airway secretions promotes recurrent cycles of pulmonary infection and inflammation. In recent years, novel drugs have been developed to alter the properties of the secretions in an attempt to aid chest physiotherapy in improving airway clearance. Once-daily nebulised recombinant human deoxyribonuclease (rhDNase; dornase alfa; Pulmozyme) is the most widely used mucoactive therapy in patients with CF. It has been shown to reduce the viscoelasticity of sputum from patients with CF and enhance the clearance of secretions. Clinical trials have shown rhDNase to be a well tolerated treatment that improves pulmonary function and reduces respiratory exacerbations. However, the response to treatment is heterogeneous and only a proportion of patients with CF actually benefit from the treatment. At present, we are unable to predict which patients will benefit from rhDNase. Many CF centers have developed formal n-of-1 trials of treatment to find out who benefits and to justify prescribing the agent. rhDNase is an expensive therapy and is mainly used in patients over the age of 5 years with moderate to severe lung disease. However, studies have shown that rhDNase may be useful in patients with milder lung disease. Comparisons with another mucoactive drug, hypertonic saline, have shown rhDNase to be more effective. Recently, it has been shown that giving rhDNase on an alternate-day basis, rather than daily, is equally effective, potentially reducing costs and treatment time.

Antiinflammatory Therapies for Cystic Fibrosis: Past, Present, and Future

Inflammation is a major component of the vicious cycle characterizing cystic fibrosis pulmonary disease. If untreated, this inflammatory process irreversibly damages the airways, leading to bronchiectasis and ultimately respiratory failure. Antiinflammatory drugs for cystic fibrosis lung disease appear to have beneficial effects on disease parameters. These agents include oral corticosteroids and ibuprofen, as well as azithromycin, which, in addition to its antimicrobial effects, also possesses antiinflammatory properties. Inhaled corticosteroids, colchicine, methotrexate, montelukast, pentoxifylline, nutritional supplements, and protease replacement have not had a significant impact on the disease. Therapy with oral corticosteroids, ibuprofen, and fish oil is limited by adverse effects. Azithromycin appears to be safe and effective, and is thus the most promising antiinflammatory therapy available for patients with cystic fibrosis. Pharmacologic therapy with antiinflammatory agents should be started early in the disease course, before extensive irreversible lung damage has occurred.