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.

Cost-effectiveness of bivalirudin versus heparin plus glycoprotein IIb/IIIa inhibitor in the treatment of acute ST-segment elevation myocardial infarction.

OBJECTIVE: To assess the cost-effectiveness of bivalirudin versus heparin and glycoprotein IIb/IIIa inhibitor (H-GPI) in patients undergoing primary percutaneous coronary intervention (PPCI) for acute ST-segment elevation myocardial infarction (STEMI), from a UK health service perspective. DESIGN: Cost-utility analysis with life-long time horizon. MAIN OUTCOME MEASURES: Costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness. METHODS: Event risks and medical resource use data derived from the HORIZONS-AMI trial were entered into a decision analytic model. Clinical events until the end of year 1 (main model) or year 3 (alternative model) were modelled in detail. Adjustments were applied to approximate UK routine practice characteristics. Life expectancy of 1-year or 3-year survivors, health-state utilities, initial hospitalisation length of stay in the comparator strategy and unit costs were based on UK sources. Costs and effects were discounted at 3.5%. RESULTS: The main model predicted bivalirudin and H-GPI patients to survive 11.52 and 11.35 (undiscounted) years on average, respectively, and to accrue 6.26 and 6.17 QALYs. Patient lifetime costs were £267 lower in the bivalirudin strategy (£12 843 vs £13 110). Extensive sensitivity and scenario analyses confirmed these results to be robust. In probabilistic analysis, quality-adjusted survival was higher and costs were lower with bivalirudin in 95.0% of simulation runs. In 99.2%, cost-effectiveness was better than £20 000 per QALY gained. Results from the alternative model were fully consistent. CONCLUSION: The use of bivalirudin instead of H-GPI in STEMI patients undergoing PPCI is cost-effective, and offers a high probability of dominance. Background treatment with aspirin and clopidogrel is assumed.

Elastolytic activity and alveolar epithelial type-1 cell damage after chronic LPS inhalation: effects of dexamethasone and rolipram.

This study investigated whether a correlation between leukocyte-derived elastolytic activity, alveolar epithelial type-1 cell damage, and leukocyte infiltration of the airways existed in guinea-pigs chronically exposed to inhaled lipopolysaccharide (LPS). The airway pathology of this model, notably the neutrophilia, resembles chronic obstructive pulmonary disease (COPD). The effect of the corticosteroid, dexamethasone, or the phosphodiesterase-4 (PDE4)-inhibitor, rolipram, on these features was studied. Conscious guinea-pigs were exposed for 1 h to single or repeated (nine) doses of LPS (30 microg ml(-1)). Dexamethasone (20 mg kg(-1), ip) or rolipram (1 mg kg(-1), ip) was administered 24 and 0.5 h before the first exposure and daily thereafter. Bronchoalveolar lavage fluid (BALF) was removed and elastolytic activity determined as the elastase-like release of Congo Red from impregnated elastin. The presence of the specific epithelial cell type-1 protein (40-42 kDa) RT1(40) in BALF was identified by Western blotting using a rat monoclonal antibody and semi-quantified by dot-blot analysis. The antibody was found to identify guinea-pig RT1(40). BALF inflammatory cells, particularly neutrophils and macrophages, and elastolytic activity were increased in chronic LPS-exposed guinea-pigs, the latter by 90%. Chronic LPS exposure also increased (10.5-fold) RT1(40) levels, indicating significant alveolar epithelial type-1 cell damage. Dexamethasone or rolipram treatment reduced the influx of inflammatory cells, the elastolytic activity (by 40% and 38%, respectively), and RT1(40) levels (by 50% and 57%, respectively). In conclusion, chronic LPS-exposed guinea-pigs, like COPD, exhibit elastolytic lung damage. This was prevented by a PDE4 inhibitor and supports their development for suppressing this leukocyte-mediated pathology.

Guinea-pig lung adenylyl and guanylyl cyclase and PDE activities associated with airway hyper- and hypo-reactivity following LPS inhalation.

The relationships between changes in in vivo airway reactivity and levels cyclicAMP and cyclicGMP were determined in guinea-pig lungs after exposure to inhaled lipopolysaccharide (LPS). After LPS (30 microg.ml(-1), 1 h), guinea-pigs displayed in vivo airway hyperreactivity (AHR) at 1 h and hyporeactivity (AHOR) at 48 h, to inhaled (20 s) histamine (1 or 3 mM, respectively). Isoprenaline-stimulated cAMP or SNAP-stimulated cGMP were determined in the lungs isolated from guinea-pigs exposed to LPS inhalation to determine whether there was a relationship between AHR or AHOR and adenylyl/guanylyl cyclase and phosphodiesterase (PDE) activities. Assays were performed in the absence and presence of the non-selective PDE inhibitor, 3-isobutyl-1-methylxanthine (IBMX). Levels of cAMP and cGMP in its presence indicated adenylyl and guanylyl cyclase activities, respectively. The difference between cAMP and cGMP levels, in the absence and presence of IBMX, reflected relevant PDE activity. In vivo AHR was associated with increased PDE activity towards cAMP and cGMP (67 and 278%, respectively) and also increased adenylyl (47%) and guanylyl (210%) cyclase activities. In vivo AHOR at 48 h after LPS inhalation was also associated with raised cyclase activity (p < 0.05), whereas relevant PDE activity declined by 79 and 68%, compared with 48 h after vehicle. Although net stimulated cGMP levels increased during AHR and AHOR and net stimulated cAMP increased during AHOR, our index of PDE activity increased during AHR and decreased during AHOR. These results therefore support the rationale for the use of PDE-inhibitors in the treatment of respiratory diseases associated with AHR.

Effect of phosphodiesterase-5 inhibitor, sildenafil (Viagra), in animal models of airways disease.

Phosphodiesterase (PDE)-5 degrades guanosine 3',5'cyclic monophosphate (cGMP) and its inhibitor sildenafil citrate (Viagra) treats erectile dysfunction by smooth muscle relaxation through elevated cGMP. Sildenafil was examined in two guinea pig models of airways disease: guinea pigs exposed to LPS or sensitized guinea pigs with atopy exposed to ovalbumen. Ovalbumen exposure caused early- and late-phase bronchoconstrictor responses, measured in conscious animals by whole-body plethysmography. Twenty-four hours after ovalbumen exposure there was airway hyperreactivity (AHR) to inhaled histamine and significantly elevated macrophages, eosinophils, and nitric oxide (NO) metabolites in bronchoalveolar lavage fluid. Sildenafil treatment (1 mg/kg, intraperitoneally) failed to affect the early and late responses but significantly reduced AHR, leukocyte influx, and elevated NO. LPS exposure (30 microg/ml) caused AHR to histamine at 1 hour and macrophage, eosinophil, and neutrophil influx at 24 hours with raised NO. Sildenafil pretreatment inhibited LPS-induced AHR, leukocyte influx, and NO generation. The effectiveness of sildenafil was not dependent on endogenous NO because inhibition of NO synthase with Nomega-nitro-L-arginine methyl ester did not prevent its action. Inhibition of PDE5 by sildenafil was confirmed by elevated S-nitroso-N-acetylpenicillamine-induced cGMP generation in isolated lungs. These antiinflammatory actions of sildenafil in guinea pig models suggest that PDE5 inhibitors may have potential in treating airways disease.

Goblet cell hyperplasia, airway function, and leukocyte infiltration after chronic lipopolysaccharide exposure in conscious Guinea pigs: effects of rolipram and dexamethasone.

The effects of chronic exposures (nine, 48 h apart) of conscious guinea pigs to lipopolysaccharide (LPS) (30 microg. ml(-1), 1 h) on airway function, airway histology (in particular, goblet cell numbers), and inflammatory cell infiltration of the lungs were examined as a model of chronic inflammatory lung disease, such as chronic obstructive pulmonary disease. The sensitivity of these parameters to treatment with the corticosteroid, dexamethasone, or the phosphodiesterase-4 (PDE4) inhibitor, rolipram, was determined. As the number of LPS exposures increased, there was a progressively persistent bronchoconstriction after each exposure. After nine LPS exposures, there was evidence on histological examination of airway infiltration of, predominantly, neutrophils in perivascular, peribronchial, and alveolar tissues. After chronic LPS exposure, the airway epithelium possessed a marked goblet cell hyperplasia and evidence of inflammatory edema, features contributory to reduced airway caliber. Treatment with dexamethasone (20 mg. kg(-1)) or rolipram (1 mg. kg(-1)), administered (i.p.) 24 and 0.5 h before exposure and 24 and 47 h after each subsequent exposure, attenuated the inflammatory cell infiltration into the airway, goblet cell hyperplasia, and inflammatory edema. Dexamethasone exacerbated, whereas rolipram reversed, the chronic LPS-induced bronchoconstrictions. This study demonstrates that chronic LPS causes persistent bronchoconstriction, neutrophilic airway inflammation, goblet cell hyperplasia, and edema. These rolipram-sensitive features suggest the potential of PDE4 inhibitors in chronic inflammatory lung diseases.

Airway function, oedema, cell infiltration and nitric oxide generation in conscious ozone-exposed guinea-pigs: effects of dexamethasone and rolipram.

1. The effects of ozone inhalation (90 min, 2.15+/-0.05 p.p.m.) and their modification by dexamethasone (20 mg kg(-1)) or the phosphodiesterase-4 inhibitor, rolipram (1 mg kg(-1)), administered (i.p.) 24 and 0.5 h before and 24 h after ozone exposure were examined in conscious guinea-pigs. 2. Ozone caused an early-phase bronchoconstriction (EPB) as a fall in specific airways conductance (sG(aw)) measured by whole body plethysmography, followed at 5 h by a late-phase bronchoconstriction (LPB) and increased respiratory rate. Rolipram did not alter this profile but dexamethasone inhibited the EPB. 3. Airway hyperreactivity to inhaled histamine (1 mM, 20 s) occurred at 0.5, 2, 12, 24 and 48 h after ozone inhalation, the 2 h change being abolished by rolipram and dexamethasone. 4. Bronchoalveolar lavage fluid (BALF) macrophages, eosinophils and neutrophils were significantly (P<0.05) elevated at 12, 24 and 48 h after ozone exposure, the 48 h influx being significantly attenuated (P<0.05) by rolipram and dexamethasone. 5. BALF nitric oxide (NO) metabolites decreased 0.5 h after ozone exposure by 52%, recovered at 2 h and significantly increased at 12 (101%) and 24 h (127%). The elevated NO was unaffected by rolipram or dexamethasone. 6. Lung oedema, measured from wet/dry weight differences, was significant 12, 24 and 48 h after ozone exposure, the latter being significantly attenuated (P<0.05) by rolipram and dexamethasone. 7. Ozone exposure of guinea-pigs produced features common to COPD. Although rolipram and dexamethasone did not affect the airway function changes, they inhibited the inflammation, airway hyperreactivity and oedema.