Treatment compliance in cystic fibrosis patients with chronic Pseudomonas aeruginosa infection treated with tobramycin inhalation powder: The FREE study

The quest to deliver high-dose rifampicin: can the inhaled approach help?

INTRODUCTION

Tuberculosis (TB) is a global health problem that poses a challenge to global treatment programs. Rifampicin is a potent and highly effective drug for TB treatment; however, higher oral doses than the standard dose (10 mg/kg/day) rifampicin may offer better efficacy in TB treatment.

AREAS COVERED

High oral dose rifampicin is not implemented in anti-TB regimens yet and requires about a 3-fold increase in dose for increased efficacy. We discuss inhaled delivery of rifampicin as an alternative or adjunct to oral high-dose rifampicin. Clinical results of safety, tolerability, and patient compliance with antibiotic dry powder inhalers are reviewed.

EXPERT OPINION

Clinical trials suggest that an approximately 3-fold increase in the standard oral dose of rifampicin may be required for better clinical outcomes. On the other hand, animal studies suggest that inhaled rifampicin can deliver a high concentration of the drug to the lungs and achieve approximately double the plasma concentration than that from oral rifampicin. Clinical trials on inhaled antibiotics suggest that dry powder inhalation is a patient-friendly and well-tolerated approach in treating respiratory infections compared to conventional treatments. Rifampicin, a well-known anti-TB drug given orally, is a good candidate for clinical development as a dry powder inhaler.

Efficacy and Safety of Dry Powder Antibiotics: A Narrative Review

The use of inhaled antibiotics was initially almost exclusively confined to patients with cystic fibrosis (CF). However, it has been extended in recent decades to patients with non-CF bronchiectasis or chronic obstructive pulmonary disease who present with chronic bronchial infection by potentially pathogenic microorganisms. Inhaled antibiotics reach high concentrations in the area of infection, which enhances their effect and enables their long-term administration to defeat the most resistant infections, while minimizing possible adverse effects. New formulations of inhaled dry powder antibiotics have been developed, providing, among other advantages, faster preparation and administration of the drug, as well as avoiding the requirement to clean nebulization equipment. In this review, we analyze the advantages and disadvantages of the different types of devices that allow the inhalation of antibiotics, especially dry powder inhalers. We describe their general characteristics, the different inhalers on the market and the proper way to use them. We analyze the factors that influence the way in which the dry powder drug reaches the lower airways, as well as aspects of microbiological effectiveness and risks of resistance development. We review the scientific evidence on the use of colistin and tobramycin with this type of device, both in patients with CF and with non-CF bronchiectasis. Finally, we discuss the literature on the development of new dry powder antibiotics.

Antimicrobial Strategies for Cystic Fibrosis

Lung infection is the leading cause of death in cystic fibrosis (CF), and antimicrobial therapies are the backbone of infection management. While many different strategies may be applied, rigorous microbiological surveillance, intensive eradication therapy, and long-term maintenance therapy based on inhaled antibiotics may be considered the main strategy for infection control in individuals with CF. While most of the existing evidence is based on infection with Pseudomonas aeruginosa, other important pathogens causing lung inflammation and deterioration exist and should be treated despite the evidence gap. In this chapter, we describe the approaches to the antimicrobial treatment of the most important pathogens in CF and the evidence behind.

Chronic inhaled antibiotic therapy in people with cystic fibrosis with Pseudomonas aeruginosa infection in Germany

BACKGROUND

Several clinical guidelines recommend chronic inhaled therapy for pwCF (people with cystic fibrosis) and chronic Pseudomonas aeruginosa infection of the lungs.

METHODS

To demonstrate what kind of therapy regimens are used in Germany, we retrospectively analysed chronic inhaled antibiotic therapy within the cohort of the German CF Registry in 2020. For comparison we also analysed the use of inhaled antibiotics in pwCF with intermittent Pseudomonas or without Pseudomonas infection.

RESULTS

A total of 1960 pwCF had chronic P. aeruginosa infection and were retrospectively evaluated. Almost 90% (n = 1751) received at least one inhaled antibiotic. The most commonly used inhaled antibiotic was colistin solution for inhalation (55.2%), followed by aztreonam solution for inhalation (32.6%) and tobramycin solution for Inhalation (30%). Almost 56% of adults and 44% of children alternated two antibiotics for inhalation. In children, alternating colistin + tobramycin was the most often used regimen. In adults, only 23% used colistin + tobramycin; there was a wide range of treatment regimens among adults using two inhaled antibiotics alternately. 2456 pwCF had no Pseudomonas infection, but almost 24% had a chronic inhaled antibiotic therapy, while 56% of 361 pwCF and intermittent chronic Pseudomonas infection had a chronic inhaled antibiotic therapy.

CONCLUSION

In all three groups the most commonly used inhaled antibiotic was colistin solution for inhalation. Almost 56% of adults and 44% of children with chronic Pseudomonas infection alternated two antibiotics for inhalation. It will be interesting to see how the introduction of the highly effective modulator elexacaftor/tezacaftor/ivacaftor will change the use of inhaled antibiotics.

Use of inhaled antibiotics among Danish patients with cystic fibrosis

BACKGROUND

Inhaled antibiotics are an important part of cystic fibrosis (CF) airway disease management and should be individualized to fit the microorganism and match patient needs. To investigate the implementation of personalized treatment, this study mapped the use of different types of inhaled antibiotics and adherence patterns.

METHODS

We performed individual structured interviews in a cross-sectional study at the CF Centre in Copenhagen, Denmark. Patients with CF older than 15 years attending clinical consultations were included. Clinical data were obtained from centralized databases.

RESULTS

Among 149 participants, 107 (72%) had indication for treatment with inhaled antibiotics. In this group, 97 (91%) reported the use of inhaled antibiotics within the last 12 months. Change from one inhaled antibiotic to another during that period was reported by 31 (29%), and 17 (25%) with Pseudomonas aeruginosa had used off-label antibiotics. Adherence to a minimum of one daily dose of antibiotic was reported by 78%, while adherence to all daily doses was 28 percentage points lower. Skipping inhalations was due to side effects and doubt about the effect in less than 5% of cases.

CONCLUSION

Change of inhaled antibiotics and use of off-label antibiotics for inhalation were common and side effects were a rare cause of nonadherence. This suggests satisfactory implementation of the principle of tailored antibiotic inhalation prescription in the Copenhagen CF population. Adherence to at least one daily inhalation dose was markedly higher than adherence to multiple daily inhalations.

The Use of Tobramycin for Pseudomonas aeruginosa: A Review

INTRODUCTION

Pseudomonas aeruginosa is a common respiratory pathogen that contributes to chronic pulmonary infection in individuals with cystic fibrosis. Guidelines recommend early intervention upon positive P. aeruginosa culture. Tobramycin has in vitro activity against Gram-negative bacteria, including P. aeruginosa, and TOBI Podhaler is indicated for the management of individuals with cystic fibrosis with P. aeruginosa infection. The dry powder inhaler formulation decreases the time required for treatment compared with nebulized solution and therefore may improve quality of life and adherence, which have a positive impact on disease progression.

AREAS COVERED

In this review, we discuss the safety and efficacy of tobramycin inhaled powder and provide insights into appropriate individuals who might benefit from a dry powder inhaler, keeping in mind that patient preference is an important consideration for therapy selection.

EXPERT OPINION

Providing a less burdensome alternative to delivering inhaled antibiotics that is more portable with a significantly shorter administration time may help improve adherence, and therefore improve outcomes. Continued development of new antibiotics to add to current regimens for eradication and control of airway microbiology, combined with more efficient delivery systems such as tobramycin inhaled powder, will help evolve the treatment of patients with CF.

The future of dry powder inhaled therapy: Promising or Discouraging for systemic disorders?

Dry powder inhalation therapy has been shown to be an effective method for treating respiratory diseases like asthma, Chronic Obstructive Pulmonary Diseases and Cystic Fibrosis. It has also been widely accepted and used in clinical practices. Such success has led to great interest in inhaled therapy on treating systemic diseases in the past two decades. The current coronavirus (COVID-19) pandemic also has increased such interest and is triggering more potential applications of dry powder inhalation therapy in vaccines and antivirus drugs. Would the inhaled dry powder therapy on systemic disorders be as encouraging as expected? This paper reviews the marketed and in-development dry powder inhaler (DPI) products on the treatment of systemic diseases, their status in clinical trials, as well as the potential for COVID-19 treatment. The advancements and unmet problems on DPI systems are also summarized. With countless attempts behind and more challenges ahead, it is believed that the dry powder inhaled therapy for the treatment of systemic disorders still holds great potential and promise.

Cysteamine Inhibits Glycine Utilisation and Disrupts Virulence in Pseudomonas aeruginosa

Pseudomonas aeruginosa is a major opportunistic human pathogen which employs a myriad of virulence factors. In people with cystic fibrosis (CF) P. aeruginosa frequently colonises the lungs and becomes a chronic infection that evolves to become less virulent over time, but often adapts to favour persistence in the host with alginate-producing mucoid, slow-growing, and antibiotic resistant phenotypes emerging. Cysteamine is an endogenous aminothiol which has been shown to prevent biofilm formation, reduce phenazine production, and potentiate antibiotic activity against P. aeruginosa, and has been investigated in clinical trials as an adjunct therapy for pulmonary exacerbations of CF. Here we demonstrate (for the first time in a prokaryote) that cysteamine prevents glycine utilisation by P. aeruginosa in common with previously reported activity blocking the glycine cleavage system in human cells. Despite the clear inhibition of glycine metabolism, cysteamine also inhibits hydrogen cyanide (HCN) production by P. aeruginosa, suggesting a direct interference in the regulation of virulence factor synthesis. Cysteamine impaired chemotaxis, lowered pyocyanin, pyoverdine and exopolysaccharide production, and reduced the toxicity of P. aeruginosa secreted factors in a Galleria mellonella infection model. Thus, cysteamine has additional potent anti-virulence properties targeting P. aeruginosa, further supporting its therapeutic potential in CF and other infections.

Post-inhalation cough with therapeutic aerosols: Formulation considerations

This review provides an assessment of post-inhalation cough with therapeutic aerosols. Factors that increase cough may be mitigated through design of the drug, formulation, and device. The incidence of cough is typically less than 5% for drugs with a nominal dose less than 1 mg, including asthma and COPD therapeutics. Cough increases markedly as the dose approaches 100 mg. This is due to changes in the composition of epithelial lining fluid (e.g., increases in osmolality, proton concentration). Whether an individual exhibits cough depends on their degree of sensitization to mechanical and chemical stimuli. Hypersensitivity is increased when the drug, formulation or disease result in increases in lung inflammation. Cough related to changes in epithelial lining fluid composition can be limited by using insoluble neutral forms of drugs and excipients.

Prevention of drug-related complications in cystic fibrosis

PURPOSE OF REVIEW

Due to continuous development of new drugs and better treatment strategies, survival of patients with cystic fibrosis has changed dramatically. Recently, targeted therapy of cystic fibrosis transmembrane conductance regulator (CFTR) modulators have become available. Despite these promising developments, treatment of this complex multiorgan disease constitutes a high and variable amount of other drugs. Complications of pharmacotherapeutic treatment are, therefore, expected to become more prevalent. This gives cause to review drug-related side effects in this new era in cystic fibrosis treatment.

RECENT FINDINGS

We will discuss cystic fibrosis-related pharmacotherapies with a focus on indication of treatment, side effects and their complications, drug--drug interactions, and options to monitor and prevent drug-induced toxicity. Many recent publications about pharmacotherapy in cystic fibrosis, focus on antifungal therapy and CFTR modulators. We will give an overview of the most important studies.

SUMMARY

With increased life expectancy which is, in part, because of better treatment options, the burden of pharmacotherapy in cystic fibrosis patients will increase. This has a high impact on quality of life as pharmacotherapy is time consuming and may cause side effects. Therefore, it is very important to be aware of possible pharmacotherapy-related side effects and their complications, drug--drug interactions, and options to monitor and prevent drug-induced toxicity.

Cystic fibrosis year in review 2018, part 1

Cystic fibrosis research and case reports were robust in the year 2018. This report summarizes research and cases related to Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulator therapies, inflammation and infection, epidemiology and the physiologic, and imaging assessment of disease.

Adherence to long-term therapies in cystic fibrosis: a French cross-sectional study linking prescribing, dispensing, and hospitalization data

BACKGROUND

Cystic fibrosis (CF) is a life-shortening genetic condition that usually affects several organs and involves significant treatment burden. Adherence to medication is important for successful CF management.

OBJECTIVE

To describe medication adherence according to age, therapeutic class, and pharmaceutical form in adults and children followed in four regional CF centers in France.

METHODS

We conducted a cross-sectional study with non-transplanted patients followed in two adult and two pediatric centers during 2015 who were covered by the French National Health Insurance (NHI). Sociodemographic, clinical, hospitalization, and prescription data were collected from patient medical records. Medication dispensations were extracted from the regional French NHI database. Adherence was calculated over 12 months using continuous medication availability (CMA) accounting for dose adjustments and hospitalizations. Drug-specific CMA was computed in R with the AdhereR package for each medication prescribed more than 3 months, which was averaged to obtain a composite CMA score (cCMA) for all treatments and per therapeutic class as well as pharmaceutical form for each patient.

RESULTS

A total of 228 patients were included. The number of chronic medications increased with age (r=0.50, p<0.001): a median of 7 medications per patient were prescribed. The mean±SD cCMA was significantly different between age groups (p=0.0098): it was 0.71±0.20 for the 0-5 years age group, 0.73±0.16 for 6-11 years, 0.64±0.17 for 12-17 years, 0.57±0.23 for 18-25 years, and 0.65±0.20 for the over 25 years age group. cCMA varied significantly according to pharmaceutical forms: the mean±SD cCMA was 0.70±0.21 for oral medications and 0.54±0.28 for inhaled medications (p<0.001).

CONCLUSION

This study suggests that adherence to medication regimens in CF patients remains suboptimal and varies substantially between age groups and pharmaceutical forms. These variations in adherence should be considered when developing effective strategies to improve adherence.