Low doses of dexamethasone constantly delivered by autologous erythrocytes slow the progression of lung disease in cystic fibrosis patients

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Abstract

Objective: To evaluate the safety and efficacy of the administration of low doses of glucocorticoids in patients with cystic fibrosis (CF) by using autologous erythrocytes loaded with dexamethasone 21-phosphate. Study design: Nine consecutive CF patients (patients nos. 1–9) received autologous erythrocytes loaded with increasing amounts of dexamethasone 21-phosphate to obtain a slow delivery of dexamethasone in circulation. The appearance of possible adverse effects, the reproducibility of the procedure, and the dexamethasone pharmacokinetics were evaluated. Subsequently, patient no. 9 and eight additional patients (patient nos. 10–17) received dexamethasone 21-phosphate-loaded erythrocytes at 1-month intervals to evaluate the efficacy of continuous release in circulation of low doses of dexamethasone. Results: Erythrocytes from CF patients can be processed to be loaded with increasing dexamethasone 21-P concentrations. Once reinfused in respective donors, a slow and prolonged delivery of dexamethasone in the blood stream was measured up to 28 days. Repeated administrations of drug-loaded erythrocytes at 4-week intervals for 15 months showed that very low doses of glucocorticoids provide significant improvement in FEV1 values and significant reduction of infective relapses due to Pseudomonas aeruginosa without adverse effects. Conclusions: The administration of very low doses of glucocorticoids using autologous erythrocytes is possible, with benefits for patients and without side effects. This method is likely to be extended to other chronic diseases.

Introduction

Cystic fibrosis (CF) is one of the most common and serious inherited disorders associated with considerable morbidity and high-case fatality. Lung disease is the major cause of morbidity in CF, being characterized by persistent bacterial infection leading to inflammation and long-term lung damage (bronchiectasis), respiratory failure, and death [1], [2]. Persistent airway inflammation begins at a very early stage in these patients [3] and continues throughout life. Controlling the inflammatory process early in the course of disease may limit the damaging effects of excessive inflammation, thus delaying the progression of pulmonary deterioration and potentially decreasing morbidity and mortality. Glucocorticoid drugs have been studied as potential agents for long-term anti-inflammatory therapy in CF patients [4]. Although oral glucocorticoids are associated with reduced progression of pulmonary disease, the risk of clinically significant adverse effects (such as growth retardation, glucose abnormalities, and cataract formation) [5] limits long-term therapy. However, whether these risks balance the benefits of improved lung function for patients in which respiratory failure represents a major cause of death is still unclear. Furthermore, it has been reported that a reduced concentration of oral glucocorticoids is associated with minimal complications [6]. A recent assessment of the effectiveness of oral steroids in the Cochrane Cystic Fibrosis and Genetic Disorders Group specialist trial register [7] suggested that oral glucocorticoids appear to slow the progression of lung disease and recommended a risk–benefit analysis of low-dose glucocorticoids. Engineered erythrocytes have been proposed as drug delivery systems [8], [9], [10], [11], [12], [13], [14], and previous experience [15], [16], [17] has demonstrated that the nondiffusible pro-drug dexamethasone 21-phosphate (Dex 21-P) can be entrapped in human erythrocytes where it is slowly dephosphorylated to the corresponding diffusible glucocorticoid analogue dexamethasone. We have evaluated in a group of CF patients the safety and efficacy of very-low doses of glucocorticoids administered encapsulated in autologous red blood cells (RBCs) once every 4 weeks for 15 months. The results obtained are summarized in this paper.

Section snippets

Study subjects

The goal of the clinical trial was to evaluate the safety and efficacy of the administration of low doses of corticosteroid in CF patients taking an advantage of the use of autologous erythrocytes loaded with Dex 21-P to obtain a slow delivery of dexamethasone in circulation. For the study, we recruited 17 CF patients homozygous for ΔF508 deletion [18], ranging from 12 to 26 years. Inclusion criteria for patients enrolment included the following: forced expiratory volume in 1 s (FEV1) at least

Dexamethasone 21-P encapsulation in CF patient erythrocytes

Dex 21-P was encapsulated in erythrocytes of CF patients processing 50 ml of blood samples by a loading procedure as reported by Magnani et al. [16]. At the end of the procedure, 82 ± 8 ml of suspension of RBCs at 9.96 ± 2% hematocrit was obtained with a cell recovery of 43 ± 5%. To evaluate the safety of the procedure, autologous erythrocytes loaded with increasing amounts of drug (1.19–14.5 mg) were administered to eight different patients. The different amounts of Dex 21-P in RBCs were

Discussion

Anti-inflammatory therapy is a strategy for treating CF pulmonary disease because it is directed at one of the primary pathophysiologic mechanisms responsible for progressive lung damage [19]. Several targets for anti-inflammatory therapy are available; however, efforts are focused on reducing local neutrophil infiltrations, and consequently, glucocorticoids are major candidates [20]. Also, if oral glucocorticoids are associated with reduced progression of pulmonary disease, the risk of

Acknowledgements

We thank the patients and physicians of the “Bambino Gesù” Hospital in Rome (Italy) for their invaluable collaboration. Moreover, we thank DIDECO (Italy) for providing the “Red Cell Loader”. We thank Prof. Andrea De Gaetano (Institute of Biomathematics, University of Urbino, Urbino, Italy) for his helpful consultation. This work was partially supported by the Italian Ministry of Health, the National Research Council, the Target Project on Biotechnology, and FIRB funds (COD. RBNE 01TBTR),

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