Inhaled dry powder mannitol in children with cystic fibrosis: A randomised efficacy and safety trial

[Primary ciliary dyskinesia]

Primary ciliary dyskinesia (PCD) is a rare genetic disorder with a variable clinical phenotype that is accompanied by reduced motility of the cilia in the respiratory tract and numerous other organs. This leads to various characteristic symptoms and disease manifestations, primarily affecting the lungs (chronic persistent productive cough, bronchiectasis), the nose and paranasal sinuses (chronic persistent rhinitis or rhinosinusitis) as well as the middle ear (chronic otitis media, middle ear effusion). Moreover, PCD is associated with impaired fertility or lateralization defects (situs anomalies, congenital heart defects). The diagnostics of PCD are complex and require a combination of several sophisticated instrument-based diagnostic procedures. Through thorough history taking and evaluation, suspected cases can be comparatively well identified based on typical clinical features and referred to further diagnostics. In recent years, molecular genetic analysis through panel diagnostics or whole exome and whole genome sequencing, has gained in importance as this enables affected individuals to participate in disease-specific and genotype-specific clinical trials. Although the current treatment is purely symptomatic, the earliest possible diagnosis is crucial for connecting patients to specialized PCD centers, which can have a significant impact on the clinical course of the affected individuals.

Expert group recommendation on inhaled mucoactive drugs in pediatric respiratory diseases: an Indian perspective

Background

Currently, there are no guidelines or consensus statements about the usage of inhaled mucoactive drugs in pediatric respiratory disease conditions from an Indian perspective.

Objective

To develop a practical consensus document to help pediatricians in clinical decision-making when choosing an appropriate mucoactive drug for the management of specific respiratory disease conditions.

Methods

A committee of nine experts with significant experience in pediatric respiratory disease conditions and a microbiological expert constituted the panel. An electronic search of the PubMed/MEDLINE, Cochrane Library, Scopus, and Embase databases was undertaken to identify relevant articles. Various combinations of keywords such as inhaled, nebulized, mucoactive, mucolytic, mucokinetic, expectorants, mucoregulators, mucociliary clearance, respiratory disorders, pediatric, cystic fibrosis (CF), non-CF bronchiectasis, acute wheezing, asthma, primary ciliary dyskinesia (PCD), critically ill, mechanical ventilation, tracheomalacia, tracheobronchomalacia, esophageal atresia (EA), tracheoesophageal fistula (TEF), acute bronchiolitis, sputum induction, guideline, and management were used. Twelve questions were drafted for discussion. A roundtable meeting of experts was conducted to arrive at a consensus. The level of evidence and class of recommendation were weighed and graded.

Conclusions

Inhaled mucoactive drugs (hypertonic saline, dry powder mannitol, and dornase alfa) can enhance mucociliary clearance in children with CF. Experts opined that hypertonic saline could be beneficial in non-CF bronchiectasis, acute bronchiolitis, and PCD. The current state of evidence is inadequate to support the use of inhaled mucoactive drugs in asthma, acute wheezing, tracheomalacia, tracheobronchomalacia, and EA with TEF.

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.

Dry Powder Inhalation for Lung Delivery in Cystic Fibrosis

Pulmonary drug delivery has long been used for local and systemic administration of different medications used in acute and chronic respiratory diseases. Certain lung diseases, such as cystic fibrosis, rely heavily on chronic treatments, including targeted lung delivery. Pulmonary drug delivery possesses various physiological advantages compared to other delivery methods and is also convenient for the patient to use. However, the formulation of dry powder for pulmonary delivery proves challenging due to aerodynamic restrictions and the lower tolerance of the lung. The aim of this review is to provide an overview of the respiratory tract structure in patients with cystic fibrosis, including during acute and chronic lung infections and exacerbations. Furthermore, this review discusses the advantages of targeted lung delivery, including the physicochemical properties of dry powder and factors affecting clinical efficacy. Current inhalable drug treatments and drugs currently under development will also be discussed.

Cystic Fibrosis: Back to the Basics

Cystic fibrosis (CF) is the most common genetic disorder in Caucasian individuals, with an incidence of 1/2,500-3,500 live births. When CF was first described in 1938, most children died in infancy. Currently, the average lifespan is 28-47.7 years. Although new breakthroughs have occurred, CF is still incurable. Both early diagnosis and treatment by multidisciplinary teams are essential to optimize short- and long-term outcomes. It is imperative for neonatal clinicians to keep up to date on the most current research, treatment, and management of CF to provide the best outcomes. This article offers clinicians an updated review of the pathophysiology and clinical manifestations of CF, as well as current evidence-based diagnostics and treatment regimens.

Macroporous Mannitol Granules Produced by Spray Drying and Sacrificial Templating

In pharmaceutical applications, the porous particles of organic compounds can improve the efficiency of drug delivery, for example into the pulmonary system. We report on the successful preparation of macroporous spherical granules of mannitol using a spray-drying process using polystyrene (PS) beads of ~340 nm diameter as a sacrificial templating agent. An FDA-approved solvent (ethyl acetate) was used to dissolve the PS beads. A combination of infrared spectroscopy and thermogravimetry analysis proved the efficiency of the etching process, provided that enough PS beads were exposed at the granule surface and formed an interconnected network. Using a lab-scale spray dryer and a constant concentration of PS beads, we observed similar granule sizes (~1-3 microns) and different porosity distributions for the mannitol/PS mass ratio ranging from 10:1 to 1:2. When transferred to a pilot-scale spray dryer, the 1:1 mannitol/PS composition resulted in different distributions of granule size and porosity depending on the atomization configuration (two-fluid or rotary nozzle). In all cases, the presence of PS beads in the spray-drying feedstock was found to favor the formation of the α mannitol polymorph and to lead to a small decrease in the mannitol decomposition temperature when heating in an inert atmosphere.

Development of a Spray-Dried Formulation of Peptide-Dna Nanoparticles into a Dry Powder for Pulmonary Delivery Using Factorial Design

Background

Gene therapy via pulmonary delivery holds the potential to treat various lung pathologies. To date, spray drying has been the most promising method to produce inhalable powders. The present study determined the parameters required to spray dry nanoparticles (NPs) that contain the delivery peptide, termed RALA (N-WEARLARALARALARHLARALARALRACEA-C), complexed with plasmid DNA into a dry powder form designed for inhalation.

Methods

The spray drying process was optimised using full factorial design with 19 randomly ordered experiments based on the combination of four parameters and three centre points per block. Specifically, mannitol concentration, inlet temperature, spray rate, and spray frequency were varied to observe their effects on process yield, moisture content, a median of particle size distribution, Z-average, zeta potential, encapsulation efficiency of DNA NPs, and DNA recovery. The impact of mannitol concentration was also examined on the spray-dried NPs and evaluated via biological functionality in vitro.

Results

The results demonstrated that mannitol concentration was the strongest variable impacting all responses apart from encapsulation efficiency. All measured responses demonstrated a strong dependency on the experimental variables. Furthermore, spray drying with the optimal variables in combination with a low mannitol concentration (1% and 3%, w/v) produced functional RALA/pDNA NPs.

Conclusion

The optimal parameters have been determined to spray dry RALA/pDNA NPs into an dry powder with excellent biological functionality, which have the potential to be used for gene therapy applications via pulmonary delivery.

Inhaled Dry Powder Mannitol Treatment in Pediatric Patients with Cystic Fibrosis: Evaluation of Clinical Data in a Real-World Setting

Background: Cystic fibrosis (CF) is a genetic disorder, in which defective clearance of airway secretions leads to progressive lung function loss. Inhaled mannitol is used to increase sputum and mucociliary clearance. There are little data from real-world studies on the effectiveness of mannitol in children. Our objective was to evaluate the spirometry and clinical results of mannitol in pediatric patients. Methods: We retrospectively reviewed the records of 30 children and adolescents with CF receiving inhaled mannitol who were already on recombinant human deoxyribonuclease (rhDNase) treatment. The change in forced expiratory volume in 1 second (FEV₁) from baseline at 2-4 months was the primary outcome. Secondary measures were other spirometry results, body mass index (BMI), hospital admissions, sputum characteristics, and positive bacterial colonization. Results: Compared to baseline, we found significant improvement in percent predicted FEV₁ at 2-4 months of treatment; 84.50 (58.00-99.00) vs. 96.00 (66.00-106.00) (P = 0.0007). The absolute change in FEV₁ was +11.5% at 2-4 months, +6.5% at 5-7 months, and +4% at 8-12 months. Also, significant improvements in other spirometry results were observed. Adolescents had significantly lower FEV₁ results, but the improvement in their lung function was sustained for a more extended period than children. Mannitol provided easier sputum removal, increased sputum volume, significant decline in hospitalizations, and significantly fewer patients with positive sputum cultures. A significant increase in BMI at 8-12 months was observed. Cough was the most frequent adverse effect. Conclusion: In a real-world setting, our results demonstrated that adding mannitol to rhDNase therapy is tolerable in pediatric patients with CF and may provide improved spirometry and clinical outcomes. In addition, our results showed that mannitol provided recovery in overall lung function at 2-4 months, which was sustained up to 12 months together with improved BMI, easier sputum removal, and a decline in bacterial colonization and hospital admissions. However, cough was the most frequent side effect.

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.

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.

Treatment of Pulmonary Disease of Cystic Fibrosis: A Comprehensive Review

Cystic fibrosis (CF) is a genetic disease that causes absence or dysfunction of a protein named transmembrane conductance regulatory protein (CFTR) that works as an anion channel. As a result, the secretions of the organs where CFTR is expressed are very viscous, so their functionality is altered. The main cause of morbidity is due to the involvement of the respiratory system as a result of recurrent respiratory infections by different pathogens. In recent decades, survival has been increasing, rising by around age 50. This is due to the monitoring of patients in multidisciplinary units, early diagnosis with neonatal screening, and advances in treatments. In this chapter, we will approach the different therapies used in CF for the treatment of symptoms, obstruction, inflammation, and infection. Moreover, we will discuss specific and personalized treatments to correct the defective gene and repair the altered protein CFTR. The obstacle for personalized CF treatment is to predict the drug response of patients due to genetic complexity and heterogeneity of uncommon mutations.

Archaeal hyperthermostable mannitol dehydrogenases: A promising industrial enzymes for d-mannitol synthesis

Recently, the term healthy lifestyle connected to low-calorie diets, although it is not possible to get rid of added sugars as a source of energy, despite the close relation of added sugars to some diseases such as obesity, diabetes, etc. As a result, the sweetener market has flourished, which has led to increased demand for natural sweeteners such as polyols, including d-mannitol. Various methods have been developed to produce d-mannitol to achieve high productivity and low cost. In particular, metabolic engineering for d-mannitol considers one of the most promising approaches for d-mannitol production on the industrial scale. To date, the chemical process is not ideal for large-scale production because of its multistep mechanism involving hydrogenation and high cost. In this review, we highlight and present a comparative evaluation of the biochemical parameters that affecting d-mannitol synthesis from Thermotoga neapolitana and Thermotoga maritima mannitol dehydrogenase (MtDH) as a potential contribution for d-mannitol bio-synthesis. These species were selected because purified mannitol dehydrogenases from both strains have been reported to produce d-mannitol with no sorbitol formation under temperatures (90-120 °C).

[Management of Primary Ciliary Dyskinesia]

Die Primäre Ciliäre Dyskinesie (PCD, MIM 242650) ist eine seltene hereditäre Multisystemerkrankung mit klinisch heterogenem Phänotyp. Leitsymptom ist eine chronische Sekretretention der oberen und unteren Atemwege, welche durch die Dysfunktion motiler respiratorischer Zilien entsteht. In der Folge kommt es zur Ausbildung von Bronchiektasen, häufig zu einer Infektion durch Pseudomonas aeruginosa sowie einer abnehmenden Lungenfunktion bis hin zum Lungenversagen.

Bislang gibt es kaum evidenzbasierte Therapieempfehlungen, da randomisierte Langzeitstudien zur Behandlung der PCD fehlten. In diesem Jahr wurden die Daten einer ersten placebokontrollierten Medikamentenstudie bei PCD veröffentlicht. Anlässlich dieses Meilensteins im Management der PCD wurde der vorliegende Übersichtsartikel als Konsens von Patientenvertretern sowie Klinikern, die langjährige Erfahrung in der Behandlung der PCD haben, verfasst. Diese Arbeit bietet eine Zusammenfassung aktuell eingesetzter Behandlungsverfahren, die überwiegend auf persönlichen Erfahrungen und Expertenmeinungen beruhen oder von anderen Atemwegserkrankungen wie der Cystischen Fibrose (CF), COPD oder Bronchiektasen-Erkrankung abgeleitet werden. Da es derzeit keine kurative Therapie für PCD gibt, stehen symptomatische Maßnahmen wie die regelmäßige Reinigung der Atemwege und die Behandlung von rezidivierenden Atemwegsinfektionen im Fokus. Nicht respiratorische Manifestationen werden organspezifisch behandelt. Um neben der ersten Medikamentenstudie mehr evidenzbasiertes Wissen zu generieren, werden weitere Projekte etabliert, u. a. ein internationales PCD-Register. Hierüber wird Patienten der Zugang zu klinischen und wissenschaftlichen Studien erleichtert und die Vernetzung behandelnder Zentren gefördert. Des Weiteren können Erkenntnisse über eine Genotyp-spezifische Erkrankungsschwere erlangt werden, um folglich die therapeutische Versorgung der Patienten zu verbessern und somit zu individualisieren.

Motile ciliopathies

Motile cilia are highly complex hair-like organelles of epithelial cells lining the surface of various organ systems. Genetic mutations (usually with autosomal recessive inheritance) that impair ciliary beating cause a variety of motile ciliopathies, a heterogeneous group of rare disorders. The pathogenetic mechanisms, clinical symptoms and severity of the disease depend on the specific affected genes and the tissues in which they are expressed. Defects in the ependymal cilia can result in hydrocephalus, defects in the cilia in the fallopian tubes or in sperm flagella can cause female and male subfertility, respectively, and malfunctional motile monocilia of the left-right organizer during early embryonic development can lead to laterality defects such as situs inversus and heterotaxy. If mucociliary clearance in the respiratory epithelium is severely impaired, the disorder is referred to as primary ciliary dyskinesia, the most common motile ciliopathy. No single test can confirm a diagnosis of motile ciliopathy, which is based on a combination of tests including nasal nitric oxide measurement, transmission electron microscopy, immunofluorescence and genetic analyses, and high-speed video microscopy. With the exception of azithromycin, there is no evidence-based treatment for primary ciliary dyskinesia; therapies aim at relieving symptoms and reducing the effects of reduced ciliary motility.

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.

Recent advances in the biotechnological production of erythritol and mannitol

Dietary habits that include an excess of added sugars have been strongly associated with an increased risk of obesity, heart disease, diabetes, and tooth decay. With this association in view, modern food systems aim to replace added sugars with low calorie sweeteners, such as polyols. Polyols are generally not carcinogenic and do not trigger a glycemic response. Furthermore, owing to the absence of the carbonyl group, they are more stable compared to monosaccharides and do not participate in Maillard reactions. As such, since polyols are stable at high temperatures, and they do not brown or caramelize when heated. Therefore, polyols are widely used in the diets of hypocaloric and diabetic patients, as well as other specific cases where controlled caloric intake is required. In recent years, erythritol and mannitol have gained increased importance, especially in the food and pharmaceutical industries. In these areas, research efforts have been made to improve the productivity and yield of the two polyols, relying on biotechnological manufacturing methods. The present review highlights the recent advances in the biotechnological production of erythritol and mannitol and summarizes the benefits of using the two polyols in the food and pharmaceutical industries.

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.

Repurposing excipients as active inhalation agents: The mannitol story

The story of how we came to use inhaled mannitol to diagnose asthma and to treat cystic fibrosis began when we were looking for a surrogate for exercise as a stimulus to identify asthma. We had proposed that exercise-induced asthma was caused by an increase in osmolarity of the periciliary fluid. We found hypertonic saline to be a surrogate for exercise but an ultrasonic nebuliser was required. We produced a dry powder of sodium chloride but it proved unstable. We developed a spray dried preparation of mannitol and found that bronchial responsiveness to inhaling mannitol identified people with currently active asthma. We reasoned that mannitol had potential to replace the 'osmotic' benefits of exercise and could be used as a treatment to enhance mucociliary clearance in patients with cystic fibrosis. These discoveries were the start of a journey to develop several registered products that are in clinical use globally today.

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.

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.

Impact of intestinal mannitol on hyperammonemia, oxidative stress and severity of hepatic encephalopathy in the ED

Hyperammonemia results from hepatic inability to remove nitrogenous products generated by protein metabolism of intestinal microbiota, which leads to hepatic encephalopathy (HE) in chronic liver disease (CLD). In ammonium neurotoxicity, oxidative stress (OxS) plays a pathogenic role. Our objective was to evaluate if intestinal mannitol is as effective and safe as conventional treatment for diminishing hyperammonemia, OxS, and HE in patients with CLD.

MATERIAL AND METHODS

We included 30 patients with HE classified by "Haven Criteria for Hepatic Encephalopathy". They were randomized into two groups: 1) Mannitol Group (MG) with mannitol 20% administered into the intestine by an enema, 2) conventional group (CG) with lactulose 40 g enema both substances were diluted in 800 mL of double distilled solution every 6 h; all patients received neomycin. We evaluated ammonia concentration, plasma oxidative stress, HE severity, intestinal discomfort and adverse effects.

RESULTS

Hyperammonemia (171 ± 104 vs 79 ± 49 μmol ammonia/L, p < 0.01), and oxidative stress (MDA 29 vs 27%, formazan 15 vs 11%, carbonyls 16 vs 9% and dityrosines 10 vs 5%) were reduced in MG and CG respectively. The HE severity decreased by two degrees compared to baseline values in both groups. Intestinal discomfort and electrolyte plasma alterations were less frequent (p < 0.05) in MG than CG.

CONCLUSIONS

Intestinal mannitol is as effective and safe as conventional treatment for reducing hyperammonemia, oxidative stress, and hepatic encephalopathy of CLD patients in the emergency room. Likewise, mannitol is better tolerated than conventional treatment.

The use of pulmonary clearance medications in the acutely ill patient

INTRODUCTION

Retention of airway secretions occurs in disease, leading to airway plugging, atelectasis, and worsened respiratory mechanics, making airway clearance an important therapeutic target. Areas covered: Many medications designed to enhance clearance of airway secretions are available. We will review the medications available to enhance airway clearance, their mechanisms of action, and the evidence available for their use in acutely ill patients. Expert commentary: In the cystic fibrosis (CF) population, beneficial effects have been shown in pulmonary function with the use of some of these agents. In the non-CF population, there is limited evidence regarding these medications. While some studies have found benefit, the quality of evidence is low, making it difficult to draw conclusions. While certain patients may derive benefit, the general use of these medications in acutely ill patients without CF cannot be recommended at this time.