Pooled analysis of two large randomised phase III inhaled mannitol studies in cystic fibrosis

Breath of fresh insight: unraveling the evolution of our understanding of cystic fibrosis pulmonary exacerbations

PURPOSE OF REVIEW

Pulmonary exacerbations are critical events with significant negative impacts in persons with cystic fibrosis, but their diagnosis and management are highly variable. Highly effective modulator therapies have greatly improved health and reduced exacerbation events, but have also reshaped how they present. This review discusses the complexities of the diagnosis and management of pulmonary exacerbations as well as the emerging work and evidence in this area.

RECENT FINDINGS

The shifting epidemiology and our understanding of risk factors for pulmonary exacerbations are discussed. As symptoms may be more subtle in the modulator context, novel technologies including studies of remote monitoring are presented. The continued relevance of pulmonary exacerbations, the heterogeneity in their management, as well as current and forthcoming clinical trials to optimize treatment approaches are detailed.

SUMMARY

In spite of the dramatic reductions in pulmonary exacerbations, airway infections persist, a proportion of persons with cystic fibrosis either on or off modulator therapies continue to experience exacerbation events, and long-term data is lacking. Innovative approaches and studies will be crucial to enable standardized and generalizable strategies to improve outcomes in persons with cystic fibrosis.

Mucus-targeting therapies of defective mucus clearance for cystic fibrosis: A short review

In the lungs, defective CFTR associated with cystic fibrosis (CF) represents the nidus for abnormal mucus clearance in the airways and consequently a progressive lung disease. Defective CFTR-mediated Cl^- secretion results in altered mucus properties, including concentration, viscoelasticity, and the ratio of the two mucins, MUC5B and MUC5AC. In the past decades, therapies targeting the CF mucus defect, directly or indirectly, have been developed; nevertheless, better treatments to prevent the disease progression are still needed. This review summarizes the existing knowledge on the defective mucus in CF disease and highlights it as a barrier to the development of future inhaled genetic therapies. The use of new mucus-targeting treatments is also discussed, focusing on their potential role to halt the progress of CF lung disease.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Inhaled Medicines: Past, Present, and Future

The purpose of this review is to summarize essential pharmacological, pharmaceutical, and clinical aspects in the field of orally inhaled therapies that may help scientists seeking to develop new products. After general comments on the rationale for inhaled therapies for respiratory disease, the focus is on products approved approximately over the last half a century. The organization of these sections reflects the key pharmacological categories. Products for asthma and chronic obstructive pulmonary disease include β -2 receptor agonists, muscarinic acetylcholine receptor antagonists, glucocorticosteroids, and cromones as well as their combinations. The antiviral and antibacterial inhaled products to treat respiratory tract infections are then presented. Two "mucoactive" products-dornase α and mannitol, which are both approved for patients with cystic fibrosis-are reviewed. These are followed by sections on inhaled prostacyclins for pulmonary arterial hypertension and the challenging field of aerosol surfactant inhalation delivery, especially for prematurely born infants on ventilation support. The approved products for systemic delivery via the lungs for diseases of the central nervous system and insulin for diabetes are also discussed. New technologies for drug delivery by inhalation are analyzed, with the emphasis on those that would likely yield significant improvements over the technologies in current use or would expand the range of drugs and diseases treatable by this route of administration. SIGNIFICANCE STATEMENT: This review of the key aspects of approved orally inhaled drug products for a variety of respiratory diseases and for systemic administration should be helpful in making judicious decisions about the development of new or improved inhaled drugs. These aspects include the choices of the active ingredients, formulations, delivery systems suitable for the target patient populations, and, to some extent, meaningful safety and efficacy endpoints in clinical trials.

Comparison of inhaled mannitol/dornase alfa combination and daily dornase alfa alone in children with cystic fibrosis

OBJECTIVES

Inhaled recombinant human deoxyribonuclease (dornase alfa) and osmotic agents such as inhaled mannitol are used for improving the clearance of secretions of cystic fibrosis (CF) patients. We aimed to evaluate the long-term clinical effects of adding dry powder inhaled (DPI) mannitol in subjects with CF who are taking daily dornase alfa.

METHOD

We conducted a retrospective case-control study on subjects with CF. The effect of DPI mannitol was assessed by comparing DPI mannitol and dornase alfa combination with daily dornase alfa alone in children with CF during a 12-month period. The primary outcome measures of the study were absolute changes in percent predicted forced expiratory volume in 1 s (FEV1) and FEV1 z-scores and the secondary outcomes included other spirometry indices, body mass index, frequency of pulmonary exacerbations, SPO₂ , and sputum microbiology.

RESULT

Of a total of 28 patients who committed to use DPI mannitol treatments during the study period, five had a positive challenge with DPI mannitol and two were aged over 18 years. Therefore, the mannitol treatment group consisted of 21 patients. However, the effect of DPI mannitol was analyzed using 15 patients in the mannitol treatment group who received DPI mannitol for at least 12 months, and 18 patients who only used dornase alfa constituted the control group. The median absolute change in FEV1 between baseline and the third month; and baseline and the 12th month were significantly higher in the mannitol treatment group (p = 0.038, p = 0.004, respectively). When the groups are compared with respect to absolute z-score changes, all spirometry indices, except FVC at the end of 3 months, showed statistically significant improvements in the mannitol treatment group. Some secondary outcomes like pulmonary exacerbation frequency during the study year and median absolute body mass index z-score changes from baseline to the end of the study showed no significant differences between the groups (p = 0.735, p = 0.161, respectively). No colonization changes were observed in the treatment group.

CONCLUSIONS

This study showed that in those patients who tolerated long-term (12 months) treatment with DPI mannitol and dornase alfa made greater improvements in FEV1, FVC, FEV1/FVC, FEF25-75 z-scores than treatment with dornase alfa alone in children with CF.

Cystic fibrosis

Cystic fibrosis is a monogenic disease considered to affect at least 100 000 people worldwide. Mutations in CFTR, the gene encoding the epithelial ion channel that normally transports chloride and bicarbonate, lead to impaired mucus hydration and clearance. Classical cystic fibrosis is thus characterised by chronic pulmonary infection and inflammation, pancreatic exocrine insufficiency, male infertility, and might include several comorbidities such as cystic fibrosis-related diabetes or cystic fibrosis liver disease. This autosomal recessive disease is diagnosed in many regions following newborn screening, whereas in other regions, diagnosis is based on a group of recognised multiorgan clinical manifestations, raised sweat chloride concentrations, or CFTR mutations. Disease that is less easily diagnosed, and in some cases affecting only one organ, can be seen in the context of gene variants leading to residual protein function. Management strategies, including augmenting mucociliary clearance and aggressively treating infections, have gradually improved life expectancy for people with cystic fibrosis. However, restoration of CFTR function via new small molecule modulator drugs is transforming the disease for many patients. Clinical trial pipelines are actively exploring many other approaches, which will be increasingly needed as survival improves and as the population of adults with cystic fibrosis increases. Here, we present the current understanding of CFTR mutations, protein function, and disease pathophysiology, consider strengths and limitations of current management strategies, and look to the future of multidisciplinary care for those with cystic fibrosis.

Treatment of pulmonary exacerbations in cystic fibrosis

PURPOSE OF REVIEW

This review will discuss the challenges of defining a pulmonary exacerbations in cystic fibrosis and the key pathogens, which contribute. It will discuss the treatment options currently available and the importance of preventing pulmonary exacerbations.

RECENT FINDINGS

The basis for treatment of pulmonary exacerbations remains unchanged over the past 15 years and whilst there have been trials exploring alternative antibiotics, there has been little change. However, there are ongoing studies that are expected to establish a platform for identifying best practices. Chronic cystic fibrosis therapies have been shown to reduce pulmonary exacerbations. In the era of new CFTR (cystic fibrosis transmembrane conductance regulator) modulator therapies, the number of pulmonary exacerbations are expected to be even fewer. However, it is unclear whether the other chronic therapies can be discontinued without losing their benefits in reducing exacerbations.

SUMMARY

Although there is no universal definition of a pulmonary exacerbation in cystic fibrosis, proposed definitions have many similarities. We have outlined the current recommendations for treatment of pulmonary exacerbations, including the duration and location of treatments. We have also summarized the key therapies used for prevention of pulmonary exacerbations in cystic fibrosis.

Efficacy and safety of inhaled dry-powder mannitol in adults with cystic fibrosis: An international, randomized controlled study

BACKGROUND

Mannitol is a mucoactive hyperosmotic agent used as add-on therapy in patients with cystic fibrosis (CF), administered twice-daily (BID) via a small, portable, breath-actuated dry-powder inhaler. This study was conducted to provide confirmatory evidence of mannitol's efficacy and safety in adults.

METHODS

This multicenter, double-blind, randomized, parallel-group, controlled clinical trial recruited adults (aged ≥18 years) with CF, and forced expiratory volume in 1 second (FEV₁) 40-90% predicted. Subjects received either mannitol 400 mg or mannitol 50 mg (control), BID via dry-powder inhaler for 26 weeks. Primary endpoint: FEV₁ averaged over the 26-week treatment period.

RESULTS

Of 423 subjects randomized (209 or 214 receiving mannitol 400 mg BID or control, respectively), 373 (88.2%) completed the study, with a similar proportion completing in the two groups. For FEV₁ averaged over 26 weeks, mannitol 400 mg BID was statistically superior to control (adjusted mean difference 54 mL [95% CI 8, 100 mL]; p = 0.020). This was supported by sensitivity analyses of the primary endpoint, and by observed improvements in secondary pulmonary function endpoints (eg, absolute adjusted mean difference in percent predicted FEV₁ averaged over 26 weeks 1.21% [0.07%, 2.36%]; p = 0.037). Adverse events were mainly mild or moderate in severity, with treatment-related adverse events in 15.5 and 12.2% of subjects receiving mannitol 400 mg BID and control, respectively.

CONCLUSIONS

In adults with CF, mannitol 400 mg BID inhaled as a dry-powder statistically significantly improved lung function (FEV₁) compared with control, with this improvement supported by sensitivity analyses and secondary pulmonary function endpoints. Mannitol had a good overall safety and tolerability profile. ClinicalTrials.gov: NCT02134353.

Potentiating aminoglycoside antibiotics to reduce their toxic side effects

The lack of new antibiotics necessitates the improvement of existing ones, many of which are limited by toxic side effects. Aminoglycosides, antibiotics with excellent activity and low bacterial resistance, are hampered by dose-dependent toxic effects in patients (nephrotoxicity, ototoxicity). High antibiotic concentrations are often required to treat dormant, non-dividing bacteria, though previous studies show that aminoglycosides can be activated against such bacteria by specific metabolites. Here, we employed this mechanism to greatly boost the activity of low concentrations of aminoglycosides against prevalent Gram-negative pathogens (Escherichia coli, Salmonella enterica, and Klebsiella pneumoniae), suggesting that less toxic drug concentrations might be used effectively in patients. We go on to show that this effect improved treatment of biofilms, did not increase aminoglycoside resistance, and was due to the generation of proton-motive force (PMF). By single-cell microscopy, we demonstrate that stationary-phase cells, while non-dividing, actively maintain a growth-arrested state that is not reversed by metabolite addition. Surprisingly, within starved populations, we observed rare cells (3%) that divided without added nutrients. Additionally, we discovered that mannitol could directly protect human kidney cells from aminoglycoside cytotoxicity, independent of the metabolite's effect on bacteria. This work forwards a mechanism-based strategy to improve existing antibiotics by mitigating their toxic side effects.

Successes and Challenges: Inhaled Treatment Approaches Using Magnetic Nanoparticles in Cystic Fibrosis

Magnetic nanoparticles have been largely applied to increase the efficacy of antibiotics due to passive accumulation provided by enhancing permeability and retention, which is essential for the treatment of lung infections. Recurring lung infections such as in the life-shortening genetic disease cystic fibrosis (CF) are a major problem. The recent advent of the CF modulator drug ivacaftor, alone or in combination with lumacaftor or tezacaftor, has enabled systemic treatment of the majority of patients. Magnetic nanoparticles (MNPs) show unique properties such as biocompatibility and biodegradability as well as magnetic and heat-medicated characteristics. These properties make them suitable to be used as drug carriers and hyperthermia-based agents. Hyperthermia is a promising approach for the thermal activation therapy of several diseases, including pulmonary diseases. The benefits of delivering CF drugs via inhalation using MNPs as drug carriers afford application of sufficient therapeutic dosages directly to the primary target site, while avoiding potential suboptimal pharmacokinetics/pharmacodynamics and minimizing the risks of systemic toxicity. This review explores the multidisciplinary approach of using MNPs as vehicles of drug delivery. Additionally, we highlight advantages such as increased drug concentration at disease site, minimized drug loss and the possibility of specific cell targeting, while addressing major challenges for this emerging field.

Inhaled mannitol for cystic fibrosis

BACKGROUND

Several agents are used to clear secretions from the airways of people with cystic fibrosis. Mannitol increases mucociliary clearance, but its exact mechanism of action is unknown. The dry powder formulation of mannitol may be more convenient and easier to use compared with established agents which require delivery via a nebuliser. Phase III trials of inhaled dry powder mannitol for the treatment of cystic fibrosis have been completed and it is now available in Australia and some countries in Europe. This is an update of a previous review.

OBJECTIVES

To assess whether inhaled dry powder mannitol is well tolerated, whether it improves the quality of life and respiratory function in people with cystic fibrosis and which adverse events are associated with the treatment.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises references identified from comprehensive electronic databases, handsearching relevant journals and abstracts from conferences. Date of last search: 12 December 2019.

SELECTION CRITERIA

All randomised controlled studies comparing mannitol with placebo, active inhaled comparators (for example, hypertonic saline or dornase alfa) or with no treatment.

DATA COLLECTION AND ANALYSIS

Authors independently assessed studies for inclusion, carried out data extraction and assessed the risk of bias in included studies. The quality of the evidence was assessed using GRADE.

MAIN RESULTS

Six studies (reported in 36 unique publications) were included with a total of 784 participants. Duration of treatment in the included studies ranged from 12 days to six months, with open-label treatment for an additional six months in two of the studies. Five studies compared mannitol with control (a very low dose of mannitol or non-respirable mannitol) and the final study compared mannitol to dornase alfa alone and to mannitol plus dornase alfa. Two large studies had a similar parallel design and provided data for 600 participants, which could be pooled where data for a particular outcome and time point were available. The remaining studies had much smaller sample sizes (ranging from 22 to 95) and data could not be pooled due to differences in design, interventions and population. Pooled evidence from the two large parallel studies was judged to be of low to moderate quality and from the smaller studies was judged to be of low to very low quality. In all studies, there was an initial test to see if participants tolerated mannitol, with only those who could tolerate the drug being randomised; therefore, the study results are not applicable to the cystic fibrosis population as a whole. While the published papers did not provide all the data required for our analysis, additional unpublished data were provided by the drug's manufacturer and the author of one of the studies. Pooling the large parallel studies comparing mannitol to control, up to and including six months, lung function (forced expiratory volume at one second) measured in both mL and % predicted was significantly improved in the mannitol group compared to the control group (moderate-quality evidence). Beneficial results were observed in these studies in adults and in both concomitant dornase alfa users and non-users in these studies. In the smaller studies, statistically significant improvements in lung function were also observed in the mannitol groups compared to the non-respirable mannitol groups; however, we judged this evidence to be of low to very low quality. For the comparisons of mannitol and control, we found no consistent differences in health-related quality of life in any of the domains except for burden of treatment, which was less for mannitol up to four months in the two pooled studies of a similar design; this difference was not maintained at six months. It should be noted that the tool used to measure health-related quality of life was not designed to assess mucolytics and pooling of the age-appropriate tools (as done in some of the included studies) may not be valid so results were judged to be low to very low quality and should be interpreted with caution. Cough, haemoptysis, bronchospasm, pharyngolaryngeal pain and post-tussive vomiting were the most commonly reported side effects in both treatment groups. Where rates of adverse events could be compared, statistically no significant differences were found between mannitol and control groups; although some of these events may have clinical relevance for people with CF. For the comparisons of mannitol to dornase alfa alone and to mannitol plus dornase alfa, very low-quality evidence from a 12-week cross-over study of 28 participants showed no statistically significant differences in the recorded domains of health-related quality of life or measures of lung function. Cough was the most common side effect in the mannitol alone arm but there was no occurrence of cough in the dornase alfa alone arm and the most commonly reported reason of withdrawal from the mannitol plus dornase alfa arm was pulmonary exacerbations. In terms of secondary outcomes of the review (pulmonary exacerbations, hospitalisations, symptoms, sputum microbiology), evidence provided by the included studies was more limited. For all comparisons, no consistent statistically significant and clinically meaningful differences were observed between mannitol and control treatments (including dornase alfa).

AUTHORS' CONCLUSIONS

There is moderate-quality evidence to show that treatment with mannitol over a six-month period is associated with an improvement in some measures of lung function in people with cystic fibrosis compared to control. There is low to very low-quality evidence suggesting no difference in quality of life for participants taking mannitol compared to control. This review provides very low-quality evidence suggesting no difference in lung function or quality of life comparing mannitol to dornase alfa alone and to mannitol plus dornase alfa. The clinical implications from this review suggest that mannitol could be considered as a treatment in cystic fibrosis; but further research is required in order to establish who may benefit most and whether this benefit is sustained in the longer term. Furthermore, studies comparing its efficacy against other (established) mucolytic therapies need to be undertaken before it can be considered for mainstream practice.

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.

Cost Effectiveness of Inhaled Mannitol (Bronchitol®) in Patients with Cystic Fibrosis

BACKGROUND

Inhaled mannitol (Bronchitol^®) is licensed in Australia as a safe and efficacious addition to best supportive care in patients with cystic fibrosis.

OBJECTIVE

The objective of this study was to assess the cost effectiveness of inhaled mannitol (in addition to best supportive care) in the Australian setting from the perspective of a government-funded national healthcare system.

METHODS

A probabilistic patient-level simulation Markov model estimated life-time costs and outcomes of mannitol when added to best supportive care, compared with best supportive care alone in patients aged 6 years and older. We estimated treatment-related inputs (initial change in percentage of predicted forced expiratory volume, relative reduction in severe pulmonary exacerbations, and treatment discontinuations) from two phase III trials. Longer term natural history rates of predicted forced expiratory volume decline over time and severe pulmonary exacerbation rates for best supportive care were taken from Australian CF registries. The utility value for the cystic fibrosis health state was as measured in the trials using the Health Utility Index, whereas the impact of pulmonary exacerbations and lung transplantation on utility was ascertained from the published literature. The underlying cost of managing cystic fibrosis, and the cost associated with pulmonary exacerbations and transplantations was taken from published Australian sources.

RESULTS

The addition of inhaled mannitol to best supportive care resulted in a discounted cost per quality-adjusted life-year of AU$39,165. The result was robust with 77% of probabilistic sensitivity analysis samples below a willingness-to-pay threshold of AU$45,000/quality-adjusted life-year.

CONCLUSION

Benchmarked against an implicit Australian willingness-to-pay threshold for life-threatening diseases, our model suggests inhaled mannitol provides a cost-effective addition to best supportive care in patients with cystic fibrosis, irrespective of concomitant dornase alfa use.

The pharmacokinetics, pharmacodynamics and tolerability of PUR0200, a novel tiotropium formulation, in chronic obstructive pulmonary disease

AIMS

PUR0200 is a tiotropium bromide formulation engineered with the iSPERSE dry powder delivery technology. PUR0200 is being developed as a bioequivalent alternative to tiotropium bromide, delivered using Spiriva® HandiHaler® (HH). We investigated the bronchodilator effects, pharmacokinetics and safety of PUR0200 in patients with chronic obstructive pulmonary disease (COPD).

METHODS

This was a randomized, placebo-controlled, crossover study using different PUR0200 doses and the comparator tiotropium HH. In vitro aerodynamic particle size distribution (aPSD) characterization of PUR0200 and tiotropium HH are presented. The main endpoints included forced expiratory volume in 1 s (FEV₁ ) trough and (0-24 h) and pharmacokinetic parameters.

RESULTS

The increased fine-particle fraction of PUR0200 demonstrated by testing using the next-generation impactor increased the proportion of drug available for lung deposition compared with the tiotropium HH. There was a numerical dose-response effect for PUR0200 on FEV₁ , with 3 μg demonstrating a lower effect than higher doses. The placebo-adjusted mean (95% confidence interval) increases from baseline at 24 h postdose were 150 ml (100-200), 210 ml (160-270) and 200 ml (140-250) for 3 μg, 6 μg and 9 μg doses of PUR0200, respectively. Tiotropium HH (18 μg) caused a mean 169 ml (standard deviation 157ml) improvement in trough FEV₁ , which was not significantly different to the PUR0200 effects at any of the tested doses.

CONCLUSIONS

PUR0200 treatment caused bronchodilation in COPD patients that was similar in magnitude to that caused by tiotropium HH. This enabled a similar clinical effect on lung function to be achieved with PUR0200 using a lower metered dose of tiotropium compared with tiotropium HH.

Highlights from the 2017 North American Cystic Fibrosis Conference

The 31st annual North American Cystic Fibrosis Conference (NACFC) was held in Indianapolis, IN on November 2-4, 2017. Abstracts of presentations from the conference were published in a supplement to Pediatric Pulmonology [2017; Pediatr Pulmonol Suppl. 52: S1-S776]. The current review summarizes several major topic areas addressed at the conference: the pathophysiology and basic science of cystic fibrosis (CF) lung disease, clinical trials, clinical management issues, and quality improvement (QI). In this review, we describe emerging concepts in several areas of CF research and care.

Inhaled mannitol for cystic fibrosis

BACKGROUND

Several agents are used to clear secretions from the airways of people with cystic fibrosis. Mannitol increases mucociliary clearance, but its exact mechanism of action is unknown. The dry powder formulation of mannitol may be more convenient and easier to use compared with established agents which require delivery via a nebuliser. Phase III trials of inhaled dry powder mannitol for the treatment of cystic fibrosis have been completed and it is now available in Australia and some countries in Europe. This is an update of a previous review.

OBJECTIVES

To assess whether inhaled dry powder mannitol is well tolerated, whether it improves the quality of life and respiratory function in people with cystic fibrosis and which adverse events are associated with the treatment.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises references identified from comprehensive electronic databases, handsearching relevant journals and abstracts from conferences.Date of last search: 28 September 2017.

SELECTION CRITERIA

All randomised controlled studies comparing mannitol with placebo, active inhaled comparators (for example, hypertonic saline or dornase alfa) or with no treatment.

DATA COLLECTION AND ANALYSIS

Authors independently assessed studies for inclusion, carried out data extraction and assessed the risk of bias in included studies. The quality of the evidence was assessed using GRADE.

MAIN RESULTS

Six studies (reported in 50 publications) were included with a total of 784 participants.Duration of treatment in the included studies ranged from 12 days to six months, with open-label treatment for an additional six months in two of the studies. Five studies compared mannitol with control (a very low dose of mannitol or non-respirable mannitol) and the final study compared mannitol to dornase alfa alone and to mannitol plus dornase alfa. Two large studies had a similar parallel design and provided data for 600 participants, which could be pooled where data for a particular outcome and time point were available. The remaining studies had much smaller sample sizes (ranging from 22 to 95) and data could not be pooled due to differences in design, interventions and population.Pooled evidence from the two large parallel studies was judged to be of low to moderate quality and from the smaller studies was judged to be of low to very low quality. In all studies, there was an initial test to see if participants tolerated mannitol, with only those who could tolerate the drug being randomised; therefore, the study results are not applicable to the cystic fibrosis population as a whole.While the published papers did not provide all the data required for our analysis, additional unpublished data were provided by the drug's manufacturer and the author of one of the studies.Pooling the large parallel studies comparing mannitol to control, up to and including six months, lung function (forced expiratory volume at one second) measured in both mL and % predicted was significantly improved in the mannitol group compared to the control group (moderate-quality evidence). Beneficial results were observed in these studies in adults and in both concomitant dornase alfa users and non-users in these studies. In the smaller studies, statistically significant improvements in lung function were also observed in the mannitol groups compared to the non-respirable mannitol groups; however, we judged this evidence to be of low to very low quality.For the comparisons of mannitol and control, we found no consistent differences in health-related quality of life in any of the domains except for burden of treatment, which was less for mannitol up to four months in the two pooled studies of a similar design; this difference was not maintained at six months. It should be noted that the tool used to measure health-related quality of life was not designed to assess mucolytics and pooling of the age-appropriate tools (as done in some of the included studies) may not be valid so results were judged to be low to very low quality and should be interpreted with caution. Cough, haemoptysis, bronchospasm, pharyngolaryngeal pain and post-tussive vomiting were the most commonly reported side effects in both treatment groups. Where rates of adverse events could be compared, statistically no significant differences were found between mannitol and control groups; although some of these events may have clinical relevance for people with CF.For the comparisons of mannitol to dornase alfa alone and to mannitol plus dornase alfa, very low-quality evidence from a 12-week cross-over study of 28 participants showed no statistically significant differences in the recorded domains of health-related quality of life or measures of lung function. Cough was the most common side effect in the mannitol alone arm but there was no occurrence of cough in the dornase alfa alone arm and the most commonly reported reason of withdrawal from the mannitol plus dornase alfa arm was pulmonary exacerbations.In terms of secondary outcomes of the review (pulmonary exacerbations, hospitalisations, symptoms, sputum microbiology), evidence provided by the included studies was more limited. For all comparisons, no consistent statistically significant and clinically meaningful differences were observed between mannitol and control treatments (including dornase alfa).

AUTHORS' CONCLUSIONS

There is moderate-quality evidence to show that treatment with mannitol over a six-month period is associated with an improvement in some measures of lung function in people with cystic fibrosis compared to control. There is low to very low-quality evidence suggesting no difference in quality of life for participants taking mannitol compared to control. This review provides very low-quality evidence suggesting no difference in lung function or quality of life comparing mannitol to dornase alfa alone and to mannitol plus dornase alfa.The clinical implications from this review suggest that mannitol could be considered as a treatment in cystic fibrosis; but further research is required in order to establish who may benefit most and whether this benefit is sustained in the longer term. Furthermore, studies comparing its efficacy against other (established) mucolytic therapies need to be undertaken before it can be considered for mainstream practice.

Brazilian guidelines for the diagnosis and treatment of cystic fibrosis

Cystic fibrosis (CF) is an autosomal recessive genetic disorder characterized by dysfunction of the CFTR gene. It is a multisystem disease that most often affects White individuals. In recent decades, various advances in the diagnosis and treatment of CF have drastically changed the scenario, resulting in a significant increase in survival and quality of life. In Brazil, the current neonatal screening program for CF has broad coverage, and most of the Brazilian states have referral centers for the follow-up of individuals with the disease. Previously, CF was limited to the pediatric age group. However, an increase in the number of adult CF patients has been observed, because of the greater number of individuals being diagnosed with atypical forms (with milder phenotypic expression) and because of the increase in life expectancy provided by the new treatments. However, there is still great heterogeneity among the different regions of Brazil in terms of the access of CF patients to diagnostic and therapeutic methods. The objective of these guidelines was to aggregate the main scientific evidence to guide the management of these patients. A group of 18 CF specialists devised 82 relevant clinical questions, divided into five categories: characteristics of a referral center; diagnosis; treatment of respiratory disease; gastrointestinal and nutritional treatment; and other aspects. Various professionals working in the area of CF in Brazil were invited to answer the questions devised by the coordinators. We used the PubMed database to search the available literature based on keywords, in order to find the best answers to these questions.

An update on pediatric bronchiectasis

INTRODUCTION

The prevalence and awareness of bronchiectasis not related to cystic fibrosis (CF) is increasing and it is now recognized as a major cause of respiratory morbidity, mortality and healthcare utilization worldwide. The need to elucidate the early origins of bronchiectasis is increasingly appreciated and has been identified as an important research priority. Current treatments for pediatric bronchiectasis are limited to antimicrobials, airway clearance techniques and vaccination. Several new drugs targeting airway inflammation are currently in development. Areas covered: Current management of pediatric bronchiectasis, including discussion on therapeutics, non-pharmacological interventions and preventative and surveillance strategies are covered in this review. We describe selected adult and pediatric data on bronchiectasis treatments and briefly discuss emerging therapeutics in the field. Expert commentary: Despite the burden of disease, the number of studies evaluating potential treatments for bronchiectasis in children is extremely low and substantially disproportionate to that for CF. Research into the interactions between early life respiratory tract infections and the developing immune system in children is likely to reveal risk factors for bronchiectasis development and inform future preventative and therapeutic strategies. Tailoring interventions to childhood bronchiectasis is imperative to halt the disease in its origins and improve adult outcomes.

The treatment of the pulmonary and extrapulmonary manifestations of cystic fibrosis

Cystic fibrosis (CF) is a complex multisystem disease with considerable between patient variability in its manifestations and severity. In the past several decades, the range of treatments and the evidence to support their use for the pulmonary and extrapulmonary manifestations of CF have increased dramatically, contributing to the improved median survival of patients. As therapy for CF has evolved, new challenges including treatment adherence, medication intolerance and allergy, medical complications and coping with the burden of disease in the context of having a family and managing employment have arisen. While the majority of current therapy focuses primarily on improving symptoms, new therapies (CFTR modulators) target the underlying genetic defect.

Use of FEV1 in cystic fibrosis epidemiologic studies and clinical trials: A statistical perspective for the clinical researcher

BACKGROUND

Forced expiratory volume in 1s (FEV₁) is an established marker of cystic fibrosis (CF) disease progression that is used to capture clinical course and evaluate therapeutic efficacy. The research community has established FEV₁ surveillance data through a variety of observational data sources such as patient registries, and there is a growing pipeline of new CF therapies demonstrated to be efficacious in clinical trials by establishing improvements in FEV₁.

RESULTS

In this review, we summarize from a statistical perspective the clinical relevance of FEV₁ based on its association with morbidity and mortality in CF, its role in epidemiologic studies of disease progression and comparative effectiveness, and its utility in clinical trials. In addition, we identify opportunities to advance epidemiologic research and the clinical development pipeline through further statistical considerations.

CONCLUSIONS

Our understanding of CF disease course, therapeutics, and clinical care has evolved immensely in the past decades, in large part due to the thoughtful application of rigorous research methods and meaningful clinical endpoints such as FEV₁. A continued commitment to conduct research that minimizes the potential for bias, maximizes the limited patient population, and harmonizes approaches to FEV₁ analysis while maintaining clinical relevance, will facilitate further opportunities to advance CF care.

New and emerging targeted therapies for cystic fibrosis

Cystic fibrosis (CF) is a monogenic autosomal recessive disorder that affects about 70,000 people worldwide. The clinical manifestations of the disease are caused by defects in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The discovery of the CFTR gene in 1989 has led to a sophisticated understanding of how thousands of mutations in the CFTR gene affect the structure and function of the CFTR protein. Much progress has been made over the past decade with the development of orally bioavailable small molecule drugs that target defective CFTR proteins caused by specific mutations. Furthermore, there is considerable optimism about the prospect of gene replacement or editing therapies to correct all mutations in cystic fibrosis. The recent approvals of ivacaftor and lumacaftor represent the genesis of a new era of precision medicine in the treatment of this condition. These drugs are having a positive impact on the lives of people with cystic fibrosis and are potentially disease modifying. This review provides an update on advances in our understanding of the structure and function of the CFTR, with a focus on state of the art targeted drugs that are in development.

Current and Emerging Therapies for the Treatment of Cystic Fibrosis or Mitigation of Its Symptoms

Clinical presentation of the chronic, heritable condition cystic fibrosis (CF) is complex, with a diverse range of symptoms often affecting multiple organs with varying severity. The primary source of morbidity and mortality is due to progressive destruction of the airways attributable to chronic inflammation arising from microbial colonisation. Antimicrobial therapy combined with practises to remove obstructive mucopurulent deposits form the cornerstone of current therapy. However, new treatment options are emerging which offer, for the first time, the opportunity to effect remission from the underlying cause of CF. Here, we discuss these therapies, their mechanisms of action, and their successes and failures in order to illustrate the shift in the nature of how CF will likely be managed into the future.

[Therapeutic advances in cystic fibrosis in 2014]

Twenty-five years after the cystic fibrosis (CF) gene identification, this discovery actually begins to benefit to patients. Increasing our knowledge on CFTR biology, as well as technical progress made in order to screen for new drugs have made therapeutic strategies move an important step forward. It is likely that in the forthcoming years, the panel of molecules available for CF patients will be larger, with new activators and potentiators. The disease by itself may consequently change in its natural history. CF is an example of the so-called personalized medicine, aiming to fit treatment according to patient's genetic background. Ongoing clinical trials may enlarge the actually limited eligible number of CF patients for new drugs such as ivacaftor. Beyond this exciting and promising new therapeutic approach, one may not push symptomatic treatments on the side. Improvements have been made for inhaled antibiotics administration, aiming to simplify patient's life; clinical trials using new molecules able to liquefy mucus or with anti-inflammatory properties are actually underway. One important next step in the care for CF will be to design and conduct early intervention trials in CF infants. Newborn screening program have been widely implanted around the word, and cohorts studies have shown that both functional and structural abnormalities occurred very early, making the therapeutic window of opportunity tight.

Pseudomonas aeruginosa displays an altered phenotype in vitro when grown in the presence of mannitol

D-mannitol has been approved in dry powder formulation as an effective antimucolytic agent in patients with cystic fibrosis. What is not known is the effect of adding a metabolisable sugar on the biology of chronic bacterial pathogens in the CF lung. Therefore, a series of simple in vitro experiments were performed to examine the effect of adding D-mannitol on the phenotype of the CF respiratory pathogens Pseudomonas aeruginosa and Burkholderia cenocepacia. Clinical isolates (n = 86) consisting of P. aeruginosa (n = 51), B. cenocepacia (n = 26), P. putida (n = 4), Stenotrophomonas maltophila (n = 3) and Pseudomonas spp. (n = 2) were examined by supplementing basal nutrient agar with varying concentrations of D-mannitol (0-20% [w/v]) and subsequently examining for any change in microbial phenotype. The effect of supplementation with mannitol was four-fold, namely i) To increase the proliferation and increase in cell density of all CF organisms examined, with an optimal concentration of 2-4% (w/v) D-mannitol. No such increase in cell proliferation was observed when mannitol was substituted with sodium chloride. ii) Enhanced pigment production was observed in 2/51 (3.9%) of the P. aeruginosa isolates examined, in one of the P. putida isolates, and in 3/26 (11.5%) of the B. cenocepacia isolates examined. iii). When examined at 4.0% (w/v) supplementation with mannitol, 11/51 (21.6%) P. aeruginosa isolates and 3/26 (11.5%) B. cenocepacia isolates were seen to exhibit the altered adhesion phenotype. iv). With respect to the altered mucoid phenotype, 5/51 (9.8%) P. aeruginosa produced this phenotype when grown at 4% mannitol. Mucoid production was greatest at 4%, was poor at 10% and absent at 20% (w/v) mannitol. The altered mucoid phenotype was not observed in the B. cenocepacia isolates or any of the other clinical taxa examined. Due consideration therefore needs to be given, where there is altered physiology within the small airways, leading to a potentially altered biological state of the colonising microorganisms in novel inhaled pharmaceutical interventions in CF, particularly those, which are not designated as antimicrobial agents.

Mannitol Does Not Enhance Tobramycin Killing of Pseudomonas aeruginosa in a Cystic Fibrosis Model System of Biofilm Formation

Cystic Fibrosis (CF) is a human genetic disease that results in the accumulation of thick, sticky mucus in the airways, which results in chronic, life-long bacterial biofilm infections that are difficult to clear with antibiotics. Pseudomonas aeruginosa lung infection is correlated with worsening lung disease and P. aeruginosa transitions to an antibiotic tolerant state during chronic infections. Tobramycin is an aminoglycoside currently used to combat lung infections in individuals with CF. While tobramycin is effective at eradicating P. aeruginosa in the airways of young patients, it is unable to completely clear the chronic P. aeruginosa infections in older patients. A recent report showed that co-addition of tobramycin and mannitol enhanced killing of P. aeruginosa grown in vitro as a biofilm on an abiotic surface. Here we employed a model system of bacterial biofilms formed on the surface of CF-derived airway cells to determine if mannitol would enhance the antibacterial activity of tobramycin against P. aeruginosa grown on a more clinically relevant surface. Using this model system, which allows the growth of robust biofilms with high-level antibiotic tolerance analogous to in vivo biofilms, we were unable to find evidence for enhanced antibacterial activity of tobramycin with the addition of mannitol, supporting the observation that this type of co-treatment failed to reduce the P. aeruginosa bacterial load in a clinical setting.

Inhaled mannitol for cystic fibrosis

BACKGROUND

Several agents are used to clear secretions from the airways of people with cystic fibrosis. Inhaled dry powder mannitol is now available in Australia and some countries in Europe. The exact mechanism of action of mannitol is unknown, but it increases mucociliary clearance. Phase III trials of inhaled dry powder mannitol for the treatment of cystic fibrosis have been completed. The dry powder formulation of mannitol may be more convenient and easier to use compared with established agents which require delivery via a nebuliser.

OBJECTIVES

To assess whether inhaled dry powder mannitol is well tolerated, whether it improves the quality of life and respiratory function in people with cystic fibrosis and which adverse events are associated with the treatment.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises references identified from comprehensive electronic databases, handsearching relevant journals and abstracts from conferences.Date of last search: 16 April 2015.

SELECTION CRITERIA

All randomised controlled studies comparing mannitol with placebo, active inhaled comparators (for example, hypertonic saline or dornase alfa) or with no treatment.

DATA COLLECTION AND ANALYSIS

Authors independently assessed studies for inclusion, carried out data extraction and assessed the risk of bias in included studies.

MAIN RESULTS

The searches identified nine separate studies (45 publications), of which four studies (36 publications) were included with a total of 667 participants, one study (only available as an abstract) is awaiting assessment and two studies are ongoing. Duration of treatment in the included studies ranged from two weeks to six months with open-label treatment for an additional six months in two of the studies. Three studies compared mannitol with control (a very low dose of mannitol or non-respirable mannitol); two of these were parallel studies with a similar design and data could be pooled, where data for a particular outcome and time point were available; also, one short-term cross-over study supplied additional results. The fourth study compared mannitol to dornase alfa alone and to mannitol plus dornase alfa. There was generally a low risk of bias in relation to randomisation and blinding; evidence from the parallel studies was judged to be of low to moderate quality and from the cross-over studies was judged to be of low to very low quality. While the published papers did not provide all the data required for our analysis, additional unpublished data were provided by the drug's manufacturer and the author of one of the studies. There was an initial test to see if participants tolerated mannitol, with only those who could tolerate the drug being randomised to the studies; therefore the study results are not applicable to the cystic fibrosis population as a whole.For the comparison of mannitol and control, we found no consistent differences in health-related quality of life in any of the domains, except for burden of treatment, which was less for mannitol up to four months in the two pooled studies of a similar design; this difference was not maintained at six months. Up to and including six months, lung function in terms of forced expiratory volume at one second (millilitres) and per cent predicted were significantly improved in all three studies comparing mannitol to control. Beneficial results were observed in these studies in adults and in both concomitant dornase alfa users and non users. A significant reduction was shown in the incidence of pulmonary exacerbations in favour of mannitol at six months; however, the estimate of this effect was imprecise so it is unclear whether the effect is clinically meaningful. Cough, haemoptysis, bronchospasm, pharyngolaryngeal pain and post-tussive vomiting were the most commonly reported side effects on both treatments. Mannitol was not associated with any increase in isolation of bacteria over a six-month period.In the 12-week cross-over study (28 participants), no significant differences were found in the recorded domains of health-related quality of life or measures of lung function between mannitol versus dornase alfa alone and versus mannitol plus dornase alfa. There seemed to be a higher rate of pulmonary exacerbations in the mannitol plus dornase alfa arm compared with dornase alfa alone; although not statistically significant, this was the most common reason for stopping treatment in this arm. Cough was the most common side effect in the mannitol alone arm but there was no occurrence of cough in the dornase alfa alone arm and the most commonly reported reason of withdrawal from the mannitol plus dornase alfa arm was pulmonary exacerbations. Mannitol (with or without dornase alfa) was not associated with any increase in isolation of bacteria over the 12-week period.

AUTHORS' CONCLUSIONS

There is evidence to show that treatment with mannitol over a six-month period is associated with an improvement in some measures of lung function in people with cystic fibrosis compared to control. There is no evidence that quality of life is improved for participants taking mannitol compared to control; a decrease in burden of treatment was observed up to four months on mannitol compared to control but this difference was not maintained to six months. Randomised information regarding the burden of adding mannitol to an existing treatment is limited. There is no randomised evidence of improvement in lung function or quality of life comparing mannitol to dornase alfa alone and to mannitol plus dornase alfa.Mannitol as a single or concomitant treatment to dornase alfa may be of benefit to people with cystic fibrosis, but further research is required in order to establish who may benefit most and whether this benefit is sustained in the longer term.The clinical implications from this review suggest that mannitol could be considered as a treatment in cystic fibrosis; however, studies comparing its efficacy against other (established) mucolytic therapies need to be undertaken before it can be considered for mainstream practice.

Improving complex medical care while awaiting next-generation CFTR potentiators and correctors: The current pipeline of therapeutics

While a major target in cystic fibrosis (CF) research in recent years has been the development of corrector and potentiator drugs targeting the cystic fibrosis transmembrane conductance regulator (CFTR) protein, these therapies have not yet proven robust enough to replace or eliminate other therapies that have demonstrated improved health outcomes and quality of life in patients with CF. Further, ivacaftor is only indicated for approximately 5% of the US CF population, although the FDA has recently approved lumacaftor/ivacaftor, a combination therapy intended for those homozygous for Phe508del, which should reach a much larger number of patients. This review appraises therapeutics currently available or being studied while we await the next generation of CFTR potentiators and correctors.

Inhaled therapy in cystic fibrosis: agents, devices and regimens

Key points

Summary

The recognised mainstay daily treatments for cystic fibrosis (CF) focus on inhaled and oral medications, airway clearance and optimised nutrition. This review discusses recent advances in inhaled therapies for the management of CF, including devices such as intelligent nebulisers, drug formulations and supporting evidence for inhaled antibiotics (for the management of chronic Pseudomonas aeruginosa) and muco-active drugs. We include practical advice for clinicians regarding the optimisation of inhalation technique and education. The influence of adherence on the use of inhaled therapies in CF is also reviewed.

Educational aims

Optimising inhaled mannitol for cystic fibrosis in an adult population

Abstract

There has been remarkable progress in the treatment of cystic fibrosis (CF) patients over the past 20 years. However, limitations of standard therapies have highlighted the need for a convenient alternative treatment to effectively target the pathophysiologic basis of CF-related disease by improving mucociliary clearance of airway secretions and consequently improve lung function and reduce respiratory exacerbations. Mannitol is an osmotic agent available as a dry powder, dispensed in a convenient disposable inhaler device for the treatment of adult patients with CF. Inhalation of mannitol as a dry powder is thought to change the viscoelastic properties of airway secretions, increase the hydration of the airway surface liquid and contribute to increased mucociliary and cough clearance of retained secretions. In two large phase 3 studies [1, 2], long-term use of inhaled mannitol resulted in a significant and clinically meaningful improvement in lung function relative to control in adult CF subjects and had an acceptable safety profile. Clinical experience with inhaled mannitol confirms that it is safe and effective. A minority of patients are unable to tolerate the medication. However, through training in proper inhaler technique and setting clear expectations regarding therapeutic effects, both the tolerance and adherence necessary for long term efficacy can be positively influenced.

Educational aims

Key points

The road for survival improvement of cystic fibrosis patients in Arab countries

Cystic fibrosis (CF) is a lethal, monogenic disorder that affects multiple organ systems of the body. The incidence has been described before in the Middle East to be 1 in 2000 to 1 in 5800 live births, and the median survival was estimated to be from 10 to 20 years of age. The present article attempts to revisit various facets of this disease and specifically highlights the most important lacunae that exist in treating CF. In addition, it also tries to emphasize the steps in improving the median survival of patients with CF, in these countries.

Paediatrics: messages from Munich

The aim of this article is to describe paediatric highlights from the 2014 European Respiratory Society (ERS) International Congress in Munich, Germany. Abstracts from the seven groups of the ERS Paediatric Assembly (Respiratory Physiology and Sleep, Asthma and Allergy, Cystic Fibrosis, Respiratory Infection and Immunology, Neonatology and Paediatric Intensive Care, Respiratory Epidemiology, and Bronchology) are presented in the context of the current literature.

Inhaled mannitol for non-cystic fibrosis bronchiectasis: a randomised, controlled trial

RATIONALE

Bronchiectasis is characterised by excessive production of mucus and pulmonary exacerbations. Inhaled osmotic agents may enhance mucociliary clearance, but few long-term clinical trials have been conducted.

OBJECTIVES

To determine the impact of inhaled mannitol on exacerbation rates in patients with non-cystic fibrosis (CF) bronchiectasis. Secondary endpoints included time to first exacerbation, duration of exacerbations, antibiotic use for exacerbations and quality of life (QOL) (St George's Respiratory Questionnaire, SGRQ).

METHODS

Patients with non-CF bronchiectasis and a history of chronic excess production of sputum and ≥2 pulmonary exacerbations in the previous 12 months were randomised (1:1) to 52 weeks treatment with inhaled mannitol 400 mg or low-dose mannitol control twice a day. Patients were 18-85 years of age, baseline FEV1 ≥40% and ≤85% predicted and a baseline SGRQ score ≥30.

MAIN RESULTS

461 patients (233 in the mannitol and 228 in the control arm) were treated. Baseline demographics were similar in the two arms. The exacerbation rate was not significantly reduced on mannitol (rate ratio 0.92, p=0.31). However, time to first exacerbation was increased on mannitol (HR 0.78, p=0.022). SGRQ score was improved on mannitol compared with low-dose mannitol control (-2.4 units, p=0.046). Adverse events were similar between groups.

CONCLUSIONS

Mannitol 400 mg inhaled twice daily for 12 months in patients with clinically significant bronchiectasis did not significantly reduce exacerbation rates. There were statistically significant improvements in time to first exacerbation and QOL. Mannitol therapy was safe and well tolerated.

TRIAL REGISTRATION NUMBER

NCT00669331.

Testing two different doses of tiotropium Respimat® in cystic fibrosis: phase 2 randomized trial results

BACKGROUND

Tiotropium is a once-daily, long-acting anticholinergic bronchodilator with the potential to alleviate airway obstruction in cystic fibrosis. Our objective was to evaluate the efficacy and safety of 2.5 and 5 µg once-daily tiotropium delivered via the Respimat Soft Mist Inhaler vs. placebo in people with cystic fibrosis.

METHODS

This phase 2, 12-week, randomized, double-blind, placebo-controlled parallel-group study of tiotropium Respimat as add-on to usual cystic fibrosis maintenance therapy included people with cystic fibrosis with pre-bronchodilator forced expiratory volume in 1 second (FEV1) ≥ 25% predicted. Co-primary efficacy end points were change from baseline in percent-predicted FEV1 area under the curve from 0 to 4 hours (FEV1 AUC0-4h), and trough FEV1 at the end of week 12.

FINDINGS

A total of 510 subjects with cystic fibrosis aged 5-69 years were randomized. Both doses of tiotropium resulted in significant improvement compared with placebo in the co-primary efficacy end points at the end of week 12 (change from baseline in percent-predicted FEV1 AUC0-4h: 2.5 µg: 2.94%, 95% confidence interval 1.19-4.70, p = 0.001; 5 µg: 3.39%, 95% confidence interval 1.67-5.12, p = 0.0001; in percent-predicted trough FEV1 ∶ 2.5 µg: 2.24%, p = 0.2; 5 µg: 2.22%, p = 0.02). There was a greater benefit with tiotropium 5 vs. 2.5 µg. No treatment-related adverse events or unexpected safety findings were observed in patients taking tiotropium.

CONCLUSIONS

Tiotropium significantly improved lung function in people with cystic fibrosis. The improvement was greater with the higher dose than the lower dose, with no difference in adverse events.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00737100 EudraCT 2008-001156-43.

Emerging drugs for cystic fibrosis

INTRODUCTION

Cystic fibrosis is an autosomal recessive disease, which is the result of a genetic defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Pulmonary disease accounts for over 90% of the morbidity and mortality associated with the disease. Conventionally, CF treatment has focused on symptomatic therapy.

AREAS COVERED

In the past, the emphasis for the development of CF therapeutics has previously been on addressing complications of the manifestations rather than on the underlying disease process. However, in the past few decades there has been a paradigm shift with new attention on the underlying biological mechanisms and therapies targeted at curing the disease rather than simply controlling it. This review summarizes the current CF therapeutics pipeline. These developing therapies include CFTR gene therapy, CFTR pharmacotherapeutics, osmotically active agents and anti-inflammatory therapies, as well as novel inhaled antibiotics.

EXPERT OPINION

The CF therapeutics pipeline currently holds great promise both for novel therapies directly targeting the underlying biological mechanisms of CFTR dysfunction and new symptomatic therapies. While CFTR-directed therapy has the highest potential to improve patients' outcome, it is important to continue to develop better treatment options for all aspects of CF lung disease.

Mannitol enhances antibiotic sensitivity of persister bacteria in Pseudomonas aeruginosa biofilms

The failure of antibiotic therapies to clear Pseudomonas aeruginosa lung infection, the key mortality factor for cystic fibrosis (CF) patients, is partly attributed to the high tolerance of P. aeruginosa biofilms. Mannitol has previously been found to restore aminoglycoside sensitivity in Escherichia coli by generating a proton-motive force (PMF), suggesting a potential new strategy to improve antibiotic therapy and reduce disease progression in CF. Here, we used the commonly prescribed aminoglycoside tobramycin to select for P. aeruginosa persister cells during biofilm growth. Incubation with mannitol (10-40 mM) increased tobramycin sensitivity of persister cells up to 1,000-fold. Addition of mannitol to pre-grown biofilms was able to revert the persister phenotype and improve the efficacy of tobramycin. This effect was blocked by the addition of a PMF inhibitor or in a P. aeruginosa mutant strain unable to metabolise mannitol. Addition of glucose and NaCl at high osmolarity also improved the efficacy of tobramycin although to a lesser extent compared to mannitol. Therefore, the primary effect of mannitol in reverting biofilm associated persister cells appears to be an active, physiological response, associated with a minor contribution of osmotic stress. Mannitol was tested against clinically relevant strains, showing that biofilms containing a subpopulation of persister cells are better killed in the presence of mannitol, but a clinical strain with a high resistance to tobramycin was not affected by mannitol. Overall, these results suggest that in addition to improvements in lung function by facilitating mucus clearance in CF, mannitol also affects antibiotic sensitivity in biofilms and does so through an active, physiological response.

Cystic fibrosis papers of the year 2012

This paper reviews a personal selection of three potentially important cystic fibrosis (CF) interventional studies that have been published in the 12 month period preceding the November 2012 RSM CF conference. The review highlights the difficulties in the interpretation of outcome measures in CF.