Inhaled fluticasone propionate. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in asthma

Interleukin-1alpha and tumour necrosis factor-alpha modulate airway smooth muscle DNA synthesis by induction of cyclo-oxygenase-2: inhibition by dexamethasone and fluticasone propionate

1. Previous studies have established that glucocorticoids inhibit airway smooth muscle DNA synthesis. The effects of a combination of the pro-inflammatory cytokines, interleukin-1alpha (IL-1alpha) and tumour necrosis factor-alpha (TNF-alpha) on the inhibition of DNA synthesis by glucocorticoids in human cultured airway smooth muscle have now been investigated, since these cytokines are chronically expressed in asthmatic airways. 2. Thrombin (0.3 u ml(-1)) and basic fibroblast growth factor (bFGF, 300 pM) stimulated increases in DNA synthesis which were concentration-dependently inhibited by dexamethasone (1-1000 nM). 3. The cytokine mixture, comprising IL-1alpha (0.01 and 0.1 pM) and TNF-alpha (3 and 30 pM), directly evoked increases in DNA synthesis which were attenuated by dexamethasone. However, the cytokine mixture prevented responses to bFGF or thrombin. 4. Paradoxically, in the presence of the cytokine mixture and bFGF, dexamethasone (1-1000 nM) concentration-dependently increased DNA synthesis. Furthermore, neither dexamethasone (100 nM) nor fluticasone propionate (1 nM) inhibited DNA synthesized in response to bFGF/cytokine mixture combination and dexamethasone was similarly inactive against the thrombin/cytokine mixture. 5. The levels of prostaglandin E2 (PGE2), an established inhibitor of airway smooth muscle DNA synthesis, remained below the limits of assay detection (0.05 nM) under basal conditions or following stimulation with either thrombin or bFGF. In contrast, the cytokine mixture alone, and in the presence of thrombin or bFGF, induced biologically active levels of PGE2. Dexamethasone (100 nM), the non-selective cyclo-oxygenase (COX) inhibitor indomethacin (3 microM) or the selective COX-2 inhibitor L-745,337 (0.3 microM) completely inhibited synthesis of PGE2. 6. Neither indomethacin (3 microM) nor L-745,337 (0.3 microM) influenced thrombin- or bFGF-induced DNA synthesis. However, each COX inhibitor enhanced DNA synthesis in cytokine-treated cells. 7. In unstimulated airway smooth muscle cells, COX-1, but not COX-2 protein was detectable by Western blotting. The induction of COX-2 protein by the cytokine mixture was attenuated by dexamethasone (100 nM), whereas the level of COX-1 protein was unaffected by either the cytokines or by dexamethasone. 8. Cytokine-induced, COX-2-dependent eicosanoid production inhibits DNA synthesis. The paradoxical increase in DNA synthesis observed in glucocorticoid treated airway smooth muscle stimulated by cytokine/bFGF combinations may be explained by the ability of glucocorticoids to repress COX-2 induction and prevent cytokine-induction of the DNA synthesis inhibitor, PGE2.

Rearrangement of a 16alpha,17alpha-Epoxy-16beta-methylandrostane-17beta-carbothioic Acid to a 17beta-Mercapto-16beta-methylandrostane-17alpha,16alpha-carbolactone

The 16alpha,17alpha-epoxy-16beta-methylandrostane-17beta-carbothioic acid 2b rearranges in solution at ambient temperature to the 17beta-mercapto-16beta-methylandrostane-17alpha,16alpha-carbolactone 6a, possibly via the spirocyclic alpha-thiolactone 5.

Risk-benefit assessment of fluticasone propionate in the treatment of asthma and allergic rhinitis

BENEFITS

Fluticasone propionate (FP) is a new topical corticosteroid spray for the treatment of allergic rhinitis and asthma. FP has been shown to be effective for the treatment of adult and pediatric asthma, even at rather low doses (25 microg twice daily [b.i.d.]); many studies in asthma have shown clinical efficacy of fluticasone at half the dose of the comparison steroid (such as beclomethasone dipropionate [BDP] or budesonide [BUD]). However, exact dose comparisons cannot be made because dose-ranging comparison studies have not been done. Studies in allergic rhinitis in children and adults have shown good efficacy in FP-treated patients at a dose of 200 microg once daily (o.d.), intranasally. In summary, FP is effective in both asthma and allergic rhinitis.

RISKS

FP has minimal systemic activity because the portion of drug that is swallowed is not absorbed from the gut. Thus, the amount available for systemic activity is only that which is absorbed through the nasal mucosa (in the treatment of rhinitis) or through the alveoli of the lungs (in the treatment of asthma). When laboratory assays of adrenal function or bone formation are measured, FP and other inhaled corticosteroids can be shown to cause suppression of these markers, especially at high doses. There have been no consistent reports of clinical adrenal suppression or osteoporosis caused by FP. In summary, the risk-benefit ratio of FP at the usual doses (therapeutic ratio) is very favorable. High doses may show evidence of suppression of the hypothalamic pituitary axis as measured by in vitro tests, but evidence of corresponding clinical adverse effects is lacking.

Effects of fluticasone propionate and beclomethasone dipropionate on parameters of inflammation in peripheral blood of patients with asthma

Bronchial inflammation plays a central role in asthma. We investigated whether parameters of inflammation were increased in peripheral blood. Furthermore, we tested whether fluticasone propionate (FP), a new inhaled corticosteroid (ICS), and beclomethasone dipropionate (BDP) affected these parameters. FP 750 microg/day and BDP 1500 microg/day were compared in a randomized, crossover study consisting of two 6-week treatment periods, each preceded by a 3-week placebo period. Twenty-one patients with symptomatic asthma completed the study. The results were compared with those of six normal subjects (controls). Immunophenotyping of inflammatory cells was performed in whole blood, and serum eosinophil cationic protein (ECP) was measured. With regard to clinical efficacy, ICS increased PC20 histamine by more than 1.9 doubling doses and FEV1 by more than 0.34 l. The number of CD3/HLA-DR+ lymphocytes was significantly increased in asthmatics compared to the normal subjects, both after placebo (P<0.01) and after therapy (P<0.05). The CD3/HLA-DR+ lymphocytes decreased significantly after treatment with FP (P<0.05). Serum ECP was elevated in patients without ICS and decreased after treatment with BDP (P<0.001). In conclusion, the number of CD3/HLA-DR+ lymphocytes and serum ECP levels were raised in the peripheral blood of symptomatic asthmatics, and decreased by clinically effective doses of ICS. In this respect, FP 750 microg/day was at least as effective as BDP 1500 microg/day.

The effect of fluticasone propionate on respiratory syncytial virus-induced chemokine release by a human bronchial epithelial cell line

Respiratory syncytial virus (RSV) is an important cause of bronchiolitis in infants, is an important trigger of asthma exacerbation, and stimulates chemokine production by human respiratory epithelial cells in vitro. We tested the effect of the corticosteroid fluticasone propionate (FP) on RSV-stimulated production of the chemokines interleukin 8 (IL-8) and RANTES (regulated upon activation, normal T cell expressed and secreted) by a human bronchial epithelial cell line, BEAS-2B. Confluent BEAS-2B cultures were inoculated with RSV at approximately 1 plaque-forming unit/cell, and media were collected at 24 h intervals. Concentrations of IL-8 and RANTES were measured in supernatants using ELISA. The effect of FP at varying concentrations on RSV-induced chemokine release was determined. RSV stimulated increased release of both IL-8 and RANTES, particularly at 24-48 h after virus inoculation. Significant but incomplete inhibition of RSV-stimulated increases for both chemokines was found when cultures were treated with FP at > or = 10(-8) M (for IL-8) or > or = 10(-7) M (for RANTES). There was no significant effect of FP on release of RSV itself from infected BEAS-2B cells. We conclude that a possible mechanism for the efficacy of inhaled corticosteroids in reducing the frequency or severity of asthma exacerbations is inhibition of virus-induced chemokine production by airway cells.

Heat shock protein 70 upregulation is related to HLA-DR expression in bronchial asthma. Effects of inhaled glucocorticoids

BACKGROUND AND OBJECTIVE

Antigen processing determines the production of peptides from antigens - including allergens - and their binding to class II major histocompatibility complex molecules, that stimulate T-cell responses. Heat shock protein (hsp) 70 are recognized to have a role in chaperoning antigenic peptides and in facilitating class II peptide assembly. We studied the HLA-DR and hsp70 expression on BAL cells and bronchial biopsies from asthmatics, as well as the effect of low dose fluticasone propionate treatment.

METHODS

Twenty-three asthmatics and eight normal subjects were selected. In each subject BAL and bronchial biopsies were performed. Eighteen out of 23 asthmatics, underwent the second bronchoscopy after 6 weeks of low dose inhaled fluticasone propionate treatment (250 microg b.d.) in a placebo-controlled double-blind study. BAL fluid and biopsies were processed to evaluate HLA-DR and hsp70 expression by immunochemistry methods.

RESULTS

Hsp70 and HLA-DR upregulation was present on professional and non-professional antigen presenting cells (APCs). In asthmatics, the hsp70 and HLA-DR expression was higher in BAL (hsp70 P<0.001, HLA-DR P<0.001) and bronchial epithelium (hsp70 P<0.001, HLA-DR P<0.001) when compared with controls. We also observed a significant correlation between hsp70 and HLA-DR expression in BAL (P<0.005) and epithelium (P<0.001). Fluticasone propionate treatment down-regulated the hsp70 and HLA-DR expression in BAL (hsp70 P < 0.001, HLA-DR P < 0.05) and bronchial epithelium (hsp70 P < 0.05, HLA-DR P < 0.05). A serial section comparison study showed that CD1a+ cells and macrophages were positive for both hsp70 and HLA-DR in the submucosa.

CONCLUSIONS

Our results support the hypothesis that hsp70 over-expression implies a potential role for these proteins in antigen processing and/or presentation resulting in an increased activity of APCs, which is essential for the initiation and modulation of the asthmatic immune response in chronic asthma. Fluticasone propionate induces downregulation of HLA-DR and hsp70 molecules thus regulating inflammation by affecting key mechanisms of the allergic response.

Intranasal fluticasone propionate reduces ICAM-1 on nasal epithelial cells both during early and late phase after allergen challenge

BACKGROUND

Allergen specific nasal challenge (ASNC) is an optimal method to study the pathophysiological mechanisms sustaining the allergic inflammation and in particular the adhesion molecule system, which is involved in cellular infiltration of nasal mucosa. Topical steroids have been accepted as a highly effective anti-inflammatory therapy for allergic rhinitis.

OBJECTIVE

The aim of this double-blind placebo- controlled study was the evaluation of clinical and cytological parameters, including ICAM-1 expression on nasal epithelial cells, after a 4 week treatment with nasal fluticasone propionate (200 microg/daily) or placebo, using the model of ASNC.

METHODS

Twenty allergic rhinitics underwent nasal challenge before and after treatment. The following parameters were evaluated: (i) nasal symptoms (rhinorrhoea, itching, sneezing, obstruction), (ii) inflammatory cells (eosinophils and neutrophils), (iii) ICAM-1 expression on nasal epithelial cells at baseline, 30 min (early phase) and 6 h (late phase) after ASNC.

RESULTS

Fluticasone propionate was capable of reducing: (i) clinical symptoms during both early (P<0.001) and late phase (P<0.04), (ii) eosinophil (P<0.002) and neutrophil (P<0.001) infiltrate during late phase, and (iii) ICAM-1 expression on nasal epithelial cells during both early (P < 0.01) and late phase (P < 0.03).

CONCLUSIONS

The present results demonstrate that fluticasone propionate exerts a significant action on early and late phase clinical events following specific nasal challenge, reducing also the cellular influx during the late phase. This event is likely due to the modulation of ICAM-1 expression on epithelial cells.

Efficacy of inhaled fluticasone propionate in asthma results from topical and not from systemic activity

The objective of this study was to determine whether the therapeutic benefits of inhaled fluticasone propionate are mediated through topical or systemic effects. Two hundred seventy-four patients with asthma receiving beclomethasone dipropionate or triamcinolone acetonide during a 2-wk, single-blind, run-in period were randomized to inhaled fluticasone propionate powder 100 or 500 micrograms twice daily, oral fluticasone propionate 20 mg once daily, or placebo during a 6-wk treatment period. Patients receiving inhaled fluticasone propionate had a significantly greater probability of remaining in the study over time compared with patients receiving oral fluticasone propionate or placebo (p = 0.001). FEV1 and PEF rates at end point were significantly higher with inhaled fluticasone propionate treatment regimens than with oral fluticasone propionate (with the exception of PEF rates for inhaled fluticasone propionate 100 micrograms) or placebo treatments (p < or = 0.004). Systemic exposure to fluticasone propionate as assessed by trough plasma concentrations and/or 12-hr plasma concentration area under the curve analyses (AUC12) was higher with the oral fluticasone propionate than with the two inhaled fluticasone propionate treatment groups. The results of this study suggest that the therapeutic benefits of inhaled fluticasone propionate are mediated through topical effects in the lungs and not through systemic effects.

Intranasal fluticasone propionate inhibits recovery of chemokines and other cytokines in nasal secretions in allergen-induced rhinitis

BACKGROUND

Allergen-induced nasal responses are associated with the recovery of proinflammatory mediators and cytokines. In recent years, a distinct group of chemotactic cytokines, chemokines, has been the focus of intense investigation as to their possible role in the pathogenesis of allergic diseases. Although corticosteroids have been known to be effective in the treatment of allergic diseases, their mechanism(s) of action has not been fully elucidated.

OBJECTIVES

To study the effect of topical fluticasone on the recovery of chemokines (IL-8, MIP-1 alpha, and RANTES) and other cytokines (IL-1 beta, IL-6, and GM-CSF) from nasal mucosa following allergen challenge. To correlate the improvement of rhinitis symptoms with cytokine levels during early-phase and late-phase allergic responses.

METHODS

A randomized, double-blind, placebo-controlled crossover study of fluticasone propionate, 200 micrograms q d, was performed in ten subjects with allergic rhinitis. Allergen challenge was administered after 1 week of treatment. Nasal secretions were collected immediately after challenge and during the late-phase reactions; symptom scores were recorded simultaneously. Nasal cytokines were assayed by specific ELISA.

RESULTS

The allergen challenge caused early-phase and late-phase allergic reactions and increased recovery of IL-1 beta, IL-6, IL-8, RANTES, MIP-1 alpha, and GM-CSF from the nasal mucosa. Intranasal fluticasone inhibited the allergen-induced increase in nasal symptoms. This was associated with decreases in cytokine recovery. A significant correlation was observed between decreases in cytokine levels and in symptom scores after treatment.

CONCLUSION

Our results suggest that treatment with topical fluticasone propionate inhibits allergen-induced nasal responses and the associated increase in the production/secretion of chemokines and other proinflammatory cytokines.

A 12-week dose-ranging study of fluticasone propionate powder in the treatment of asthma

Fluticasone propionate (FP) administered via metered-dose inhaler is a potent corticosteroid effective in the treatment of asthma. To evaluate the efficacy and safety of FP powder administered via a breath-activated inhaler (Diskhaler), a multicenter, double-blind, randomized, placebo-controlled, parallel-group study was conducted in adolescent and adult patients (n = 331) with mild-to-moderate asthma previously treated with beta 2-agonist therapy alone. Patients received FP powder 50, 100, or 250 micrograms or placebo twice daily for 12 weeks. FP-treated patients compared with placebo-treated patients had significantly (p < 0.001) greater improvements in morning predose forced expiratory volume in 1 sec (21-22% increase vs. 9%). Improvement in morning peak flow rate were also significantly (p < 0.001) greater with FP than with placebo (8-10% increase vs. 2% increase). There was also a significant overall treatment difference in the frequency of inhaled albuterol use (p < 0.001) and number of nighttime awakenings due to asthma (p = 0.005). There were no statistically significant difference among the FP treatment groups in any outcome measure. Physicians' global assessments also indicated significant (p < 0.001) differences in efficacy, with 67-74% of FP-treated patients rated as having "effective" or "very effective" treatment compared with 41% of placebo-treated patients. Significant beneficial effects of FP were observed in lung function and diary card parameters after just 1 week of treatment. Adverse events were similar across treatment groups and primarily related to local irritation. Effect on hypothalamic-pituitary-adrenal axis function was minimal. In summary, all three dosages of inhaled FP powder were well tolerated and improved various asthma-related variables. Improvements in pulmonary function, beyond those achieved with beta 2-agonist therapy alone, were maintained for the duration of the 12-week study.

Comparison of fluticasone propionate and beclomethasone dipropionate on direct and indirect measurements of bronchial hyperresponsiveness in patients with stable asthma

BACKGROUND

Fluticasone propionate is a new inhaled corticosteroid with a 2:1 efficacy ratio compared with beclomethasone dipropionate with regard to lung function and symptom scores, without increased systemic activity. The aim of this study was to investigate whether this was also the case for bronchial hyperresponsiveness, assessed by both a direct (histamine) and an indirect (ultrasonically nebulised distilled water (UNDW)) provocation test.

METHODS

Fluticasone propionate, 750 micrograms/day, and beclomethasone dipropionate, 1500 micrograms/day, were compared in a randomised, double blind, crossover study consisting of two six week treatment periods, each preceded by a three week single blind placebo period. Twenty one non-smoking asthmatics (mean forced expiratory volume in one second (FEV1) 74.7% predicted, mean PC20histamine 0.36 mg/ml) completed the study.

RESULTS

Fluticasone propionate and beclomethasone dipropionate improved FEV1, peak flow rates, asthma symptoms, and bronchial hyperresponsiveness to the same extent. Both fluticasone propionate and beclomethasone dipropionate caused an increase in PC20histamine (mean 2.29 [95% confidence interval 1.45 to 3.13] and 1.95 [1.07 to 2.84] doubling doses, respectively) and in PD20UNDW (1.12 [0.55 to 1.70] and 1.28 [0.88 to 1.70] doubling doses, respectively). Neither treatment changed morning serum cortisol levels, but fluticasone propionate decreased the number of peripheral blood eosinophils less than beclomethasone dipropionate, indicating smaller systemic effects of fluticasone propionate.

CONCLUSIONS

These findings show that fluticasone propionate is as effective as twice the dose of beclomethasone dipropionate on bronchial hyperresponsiveness, assessed by provocation with both histamine and UNDW, without increased systemic activity.