Randomised controlled trial of montelukast plus inhaled budesonide versus double dose inhaled budesonide in adult patients with asthma.

BACKGROUND: Inhaled corticosteroids (ICS) affect many inflammatory pathways in asthma but have little impact on cysteinyl leukotrienes. This may partly explain persistent airway inflammation during chronic ICS treatment and failure to achieve adequate asthma control in some patients. This double blind, randomised, parallel group, non-inferiority, multicentre 16 week study compared the clinical benefits of adding montelukast to budesonide with doubling the budesonide dose in adults with asthma. METHODS: After a 1 month single blind run in period, patients inadequately controlled on inhaled budesonide (800 microg/day) were randomised to receive montelukast 10 mg + inhaled budesonide 800 microg/day (n=448) or budesonide 1600 microg/day (n=441) for 12 weeks. RESULTS: Both groups showed progressive improvement in several measures of asthma control compared with baseline. Mean morning peak expiratory flow (AM PEF) improved similarly in the last 10 weeks of treatment compared with baseline in both the montelukast + budesonide group and in the double dose budesonide group (33.5 v 30.1 l/min). During days 1-3 after start of treatment, the change in AM PEF from baseline was significantly greater in the montelukast + budesonide group than in the double dose budesonide group (20.1 v 9.6 l/min, p<0.001), indicating faster onset of action in the montelukast group. Both groups showed similar improvements with respect to "as needed" beta agonist use, mean daytime symptom score, nocturnal awakenings, exacerbations, asthma free days, peripheral eosinophil counts, and asthma specific quality of life. Both montelukast + budesonide and double dose budesonide were generally well tolerated. CONCLUSION: The addition of montelukast to inhaled budesonide is an effective and well tolerated alternative to doubling the dose of inhaled budesonide in adult asthma patients experiencing symptoms and inadequate control on budesonide alone.

Analysis of montelukast in mild persistent asthmatic patients with near-normal lung function.

Few studies have specifically evaluated controller therapy in patients with mild persistent asthma. We used a subgroup analysis to investigate the effects of montelukast, a potent cysteinyl leukotriene receptor antagonist, on adult patients on the milder end of the asthma severity spectrum. We have identified seven double-blind, randomized, placebo-controlled studies of adult patients with mild-to-moderate chronic asthma in which montelukast was investigated. Subsets of patients with baseline forced expiratory volume in 1 sec (FEV1) > 80% and > 75% predicted or further restricted by less than daily rescue beta-agonist use were included as four cohorts (A, B, C, D), and efficacy measures, including change in FEV1 rescue-free days, beta-agonist use, nocturnal awakenings and blood eosinophil counts were evaluated. Cohorts A to D comprised 21%, 8%, 11%, and 4%, respectively, of patients from these studies. Mean pretreatment FEV1 ranged from 81% to 84% predicted and daily beta-agonist use from 2.4 to 4.5 puffs day(-1) in the four cohorts. Pooled results demonstrated a treatment effect for montelukast over placebo in all cohorts, for all endpoints. There was a significant improvement in FEV1 in montelukast-treated patients (7-8% over baseline) compared with placebo (1-4% over baseline, between-group difference P < or = 0.02) for all cohorts. Similarly, the percentage of rescue-free days increased substantially more with montelukast (22-30%) than with placebo (8-13%). This subgroup analysis indicates that montelukast produced improvements in parameters of asthma control in patients with milder persistent asthma that should be confirmed in additional prospective trials.

Montelukast reduces airway eosinophilic inflammation in asthma: a randomized, controlled trial.

Leukotrienes are pro-inflammatory mediators which may contribute to tissue, sputum, and blood eosinophilia seen in allergic and inflammatory diseases, including asthma. Montelukast is a cysteinyl leukotriene1 (CysLT1) receptor antagonist which improves asthma control; the aim of this study was to investigate its effect on induced sputum eosinophils. Montelukast 10 mg (n=19) or placebo (n=21) were administered orally once in the evening for 4 weeks to 40 chronic adult asthmatic patients, aged 19-64 yrs, in a double-blind, randomized, parallel group study. Patients were included if, at prestudy, they had >5% sputum eosinophils, symptomatic asthma with a forced expiratory volume in one second > or =65% of the predicted value and were being treated only with "as needed" inhaled beta2-agonists. In addition to sputum eosinophils, blood eosinophils and clinical endpoints were also assessed. Four weeks of montelukast treatment decreased sputum eosinophils from 7.5% to 3.9% (3.6% decrease, 95% confidence interval (CI) -16.6-0.4). In contrast, placebo treatment was associated with an increase in sputum eosinophils from 14.5% to 17.9% (3.4% increase, 95% CI -3.5-9.8). The least squares mean difference between groups (-11.3%, 95% CI -21.1-(-1.4)) was significant (p=0.026). Compared with placebo, montelukast significantly reduced blood eosinophils (p=0.009), asthma symptoms (p=0.001) and beta2-agonist use (p<0.001) while significantly increasing morning peak expiratory flow (p=0.001). Montelukast was generally well tolerated in this study, with a safety profile similar to the placebo. These results demonstrate that montelukast decreases airway eosinophilic inflammation in addition to improving clinical parameters. Its efficacy in the treatment of chronic asthma may be due, in part, to the effect on airway inflammation.

The effect of montelukast (MK-0476), a cysteinyl leukotriene receptor antagonist, on allergen-induced airway responses and sputum cell counts in asthma.

BACKGROUND: Cysteinyl leukotrienes are capable of inducing chemotaxis of eosinophils in vitro and within the airways of animals and humans in vivo. OBJECTIVE: We hypothesized that montelukast (MK-0476), a potent cysLT1 receptor antagonist, would protect against allergen-induced early (EAR) and late (LAR) asthmatic responses by virtue of anti-inflammatory properties. Hence, we studied the effect of pretreatment with oral montelukast on allergen-induced airway responses. As an exploratory endpoint, changes in inflammatory cell differentials and eosinophil cationic protein (ECP) were evaluated in hypertonic saline-induced sputum. METHODS: Twelve asthmatic men (20-34 years, FEV1 79-109% predicted, histamine PC20FEV1 <4 mg/mL) with dual responses to inhaled house dust mite extract participated in a two-period, double-blind, placebo-controlled, crossover study. Three oral doses of montelukast (10 mg) or matching placebo were administered 36 and 12 h before, and 12 h post-allergen. The airway response to allergen was measured by FEV1, and the EAR and LAR were expressed as the corresponding areas under the time-response curves (AUC0-3 h and AUC3-8h, respectively). During each study period, sputum was induced with 4.5% NaCl 24 h before and 24 h after a standardized allergen challenge. Processed whole sputum cytospins were stained with Giemsa, and cell counts expressed as percentage nonsquamous cells. ECP was measured by FEIA in sputum supernatants. RESULTS: All subjects completed the study. The changes in baseline FEV1 were not significantly different between the two pretreatments (P = 0.183). Montelukast significantly inhibited the EAR and LAR, reducing the AUC0-3h by 75.4% (P<0.001) and the AUC3-8h by 56.9% (P = 0.003) as compared with placebo. Sputa of nine subjects could be included in the analysis (<80% squamous cells). Allergen challenge significantly increased sputum eosinophils after placebo (mean change +/- SD: 4.8 +/- 5.8%, P = 0.038), with a similar trend after montelukast (mean change +/- SD: 4.1 +/- 5.4%; P = 0.056). The allergen-induced changes in sputum eosinophils and ECP, however, were not significantly different between the two pretreatments (P = 0.652 and P = 0.506, respectively). CONCLUSION: We conclude that oral montelukast protects against allergen-induced early and late airway responses in asthma. However, using the present dosing and sample size, this protection was not accompanied with changes in sputum eosinophil percentage or activity, which may require more prolonged pretreatment with cysLT1 receptor antagonists.

Leukotriene modifiers as novel therapeutics in asthma.

After years of research, the components of slow-reacting substance of anaphylaxis have been identified as the cysteinyl leukotrienes C4, D4, and E4. Leukotrienes are now known to be important mediators of chronic asthma. Leukotrienes cause bronchoconstriction, oedema, and mucus secretion in models of asthma and are produced in excess quantities in asthmatic patients. Leukotriene receptor antagonists and biosynthesis inhibitors have been produced to improve the signs and symptoms of asthma. These agents block laboratory challenges simulating chronic asthma such as exercise, allergen, and aspirin challenge. They also are effective in studies of chronic asthma in a wide variety of patient types demonstrating that leukotrienes are indeed important mediators of asthma. Over the next several years the appropriate place in asthma therapy for these new agents will be defined.

Pharmacokinetics, bioavailability, and safety of montelukast sodium (MK-0476) in healthy males and females.

PURPOSE: The safety, tolerability, and pharmacokinetics of intravenous *i.v.) montelukast sodium (Singulair, MK-0476), and the oral bioavailability of montelukast sodium in healthy males and healthy females were studied. METHODS: This was a two-part study. Part I was a four-period study in males of rising i.v. doses of montelukast sodium (3, 9, and 18 mg) administered as 15-minute constant-rate i.v. infusions (Periods 1-3), followed by a 10-mg oral tablet dose of montelukast sodium (Period 4) under fasting conditions. Part II was a four-period study in females of i.v. montelukast sodium (9 mg) infused over 15 and 5 minutes (Periods 5 and 6, respectively) or injected as a bolus over 2 minutes (Period 7), followed by a 10-mg oral tablet dose of montelukast sodium (Period 8). Plasma samples were collected and analyzed by HPLC. RESULTS: In males (N = 6), as the i.v. dose of montelukast sodium increased from 3 to 18 mg, the area under the plasma concentration-time curve of montelukast sodium from time 0 to infinity (AUC) increased proportionately. The mean values of plasma clearance (CL), steady-state volume of distribution (Vss), plasma terminal half-life (t1/12), and mean residence time in the body (MRTi.v.) of montelukast sodium were 45.5 ml/min, 10.5 1, 5.1 hr, and 3.9 hr, respectively, and remained essentially constant over the i.v. dosage range. Following oral administration of a 10-mg tablet of montelukast sodium, the AUC, maximum plasma concentration (Cmax), time when Cmax occurred (Tmax), apparent t1/12, mean absorption time (MAT), and bioavailability (F) of montelukast sodium averaged 2441 ng.hr/ml, 385 ng/ml. 3.7 hr, 4.9 hr, 3.4 hr, and 66%, respectively. Following i.v. administration of 9 mg of montelukast sodium to females (N = 6), the values of CL, Vss, t1/2, and MRT i.v. averaged 47.6 ml/min, 9.6 1, 4.5 hr, and 3.6 hr, respectively. Following oral administration of a 10-mg tablet to females, the mean AUC, Cmax, Tmax, apparent t1/2, MAT and F were 2270 ng.hr/ml, 350 ng/ml, 3.3 hr, 4.4 hr, 2.6 hr, and 58%, respectively. These parameter values were similar to or slightly smaller than those in healthy males receiving the same i.v. and oral doses. CONCLUSIONS: The disposition kinetics of montelukast sodium were linear. Gender had little or no effect on the kinetics of montelukast sodium. Safety results from this study indicate that intravenous doses of montelukast sodium from 3 to 18 mg and a 10-mg oral dose are well tolerated.

Effect of vitamin E deficiency and supercritical fluid aerosolized vitamin E supplementation on interleukin-1-induced oxidative lung injury in rats.

We hypothesized that alterations in lung vitamin E levels would impact the development of acute oxidative lung injury. We found that dietary induced deficiency of vitamin E diminished lung tissue levels of vitamin E and increased lung leak following intratracheal administration of interleukin-1 (IL-1) to rats. Conversely, rats administered vitamin E directly to the lungs as an inhaled aerosol (0.3-3 microns particles) formed by supercritical fluid aerosolization (SFA) had increased lung tissue vitamin E levels and decreased IL-1 induced lung leak compared to control rats. Lung myeloperoxidase (MPO) activities, reflecting neutrophil concentrations, were increased in rats given IL-1 intratracheally compared to rats given saline intratracheally but were not different for control or vitamin E depleted rats. Lung MPO activities in rats given IL-1 intratracheally were slightly higher in SFA vitamin E treated rats than in control rats. Our results suggest that vitamin E levels affect susceptibility to IL-1 induced, neutrophil-dependent lung injury. We speculate that supercritical fluid aerosol (SFA) delivery of vitamin E can rapidly increase lung vitamin E levels and decrease acute oxidative lung injury.

Interleukin-1 pretreatment prevents interleukin-1-induced lung leak in rats.

We found that rats pretreated with interleukin-1 (IL-1) intraperitoneally did not develop the acute oxidative, neutrophil-dependent lung leak that occurs after administration of IL-1 intratracheally (IL-1-induced tolerance). IL-1-pretreated rats also had increased lung catalase and glucose-6-phosphate dehydrogenase (G6PDH) activity and increased plasma catalase activity compared with sham-pretreated rats. In contrast to reducing lung leak, IL-1 pretreatment did not reduce the numbers of neutrophils that are increased in lung lavages of rats given IL-1 intratracheally. IL-1-induced tolerance to IL-1-mediated lung leak and the associated increases in lung catalase, lung G6PDH, and serum catalase activities were all prevented by treating rats with the IL-1-receptor antagonist or with N-acetyl-L-cysteine, an agent that increases intracellular glutathione levels. Our results indicate that IL-1 pretreatment confers tolerance to IL-1-mediated lung leak without decreasing IL-1-induced increases in lung neutrophils. The possible protective actions of IL-1 should be considered in experiments and clinical trials where IL-1 activity is reduced pharmacologically.

Interleukin-1-induced lung neutrophil accumulation and oxygen metabolite-mediated lung leak in rats.

We found that intratracheal administration of recombinant interleukin-1 alpha (IL-1) into rats rapidly (< 5 h) increased neutrophils in lung lavages and caused an acute edematous lung injury which was reflected by lung albumin accumulation (lung leak) and histological abnormalities (perivascular cuffing). These IL-1-dependent processes were inhibited by prior administration of recombinant IL-1 receptor antagonist and did not occur following administration of heated IL-1. Several lines of evidence suggested that neutrophil-derived oxygen metabolites contributed to lung leak. First, lung leak did not occur in rats rendered neutropenic by vinblastine treatment 4 days before IL-1 administration but did occur in neutrophil-replete rats given vinblastine 1 day before IL-1 administration and control rats given IL-1. Second, treatment with a hydroxyl radical scavenger, dimethyl sulfoxide (DMSO) or a superoxide anion scavenger, manganese superoxide dismutase, decreased lung leak, lung lavage neutrophils, and histological abnormalities in rats given IL-1 intratracheally. Third, intratracheal IL-1 administration increased lung oxidized glutathione (GSSG) levels and expired H2O2 concentrations, and these two indices of oxidative stress were decreased by dimethyl sulfoxide or manganese superoxide dismutase treatment. We conclude that intratracheal administration of IL-1 increases neutrophils in the lung and causes a neutrophil and oxygen metabolite-dependent acute edematous lung injury.

Liposome-entrapped PGE1 posttreatment decreases IL-1 alpha-induced neutrophil accumulation and lung leak in rats.

We found that treatment with liposome-entrapped prostaglandin E1 (Lip-PGE1), but not with empty liposomes and/or free PGE1, decreased the leak of intravascularly administered 125I-labeled albumin into lungs of rats given interleukin-1 alpha (IL-1 alpha) intratracheally. Lip-PGE1 treatment also decreased lung myeloperoxidase activity, lung lavage neutrophil increases, and lung histological abnormalities found in rats given IL-1 alpha intratracheally. Interestingly, decreased lung leak and lung neutrophil accumulation occurred when Lip-PGE1 was given intravenously 2.5 h after, but not immediately before, intratracheal IL-1 alpha administration. When Lip-PGE1 treatment was given both before and 2.5 h after IL-1 alpha administration, lung leak was decreased to baseline levels. Lip-PGE1 treatment given 2.5 h after IL-1 alpha administration also decreased lung oxidized glutathione levels, which increased in rats given IL-1 alpha intratracheally. We conclude that postinsult treatment with Lip-PGE1 decreases lung leak, neutrophil recruitment, and oxidative responses in lungs of rats given IL-1 alpha intratracheally.

Postinsult treatment with N-acetyl-L-cysteine decreases IL-1-induced neutrophil influx and lung leak in rats.

We found that intratracheal administration of interleukin-1 alpha (IL-1) rapidly (5 h) increased leak of 125I-labeled albumin from the blood into the lung (lung leak), influx of neutrophils into lung lavages, lung oxidized glutathione (GSSG) levels, breath hydrogen peroxide (H2O2) concentrations, and lung histological abnormalities in intact rats. Since N-acetyl-L-cysteine (NAC) increases glutathione (GSH) levels in vivo and scavenges oxygen radicals in vitro, we tested the effect of NAC given intravenously on lung changes following intratracheal IL-1 administration. We found that administration of NAC immediately before or 2.5 h after intratracheal administration of IL-1 decreased lung leak, neutrophil influx into lung lavages, and defects in lung histology. NAC treatment also increased blood acid soluble sulfhydryl levels, reduced lung GSSG increases, and decreased breath H2O2 levels in rats given IL-1 intratracheally. The latter findings are consistent with the possibility that NAC is enhancing GSH or other sulfhydryls and, as a result, reducing oxidative stress due to H2O2 or H2O2-derived products. Since postinsult treatment with NAC is effective in this relevant intact animal model of acute lung injury, we speculate that NAC may have promise in the treatment of patients with the adult respiratory distress syndrome.

Circulating xanthine oxidase mediates lung neutrophil sequestration after intestinal ischemia-reperfusion.

Injury to nonpulmonary organ systems often initiates systemic processes that cause recruitment of neutrophils to the lung. We found that rats subjected to intestinal ischemia-reperfusion (I/R) had increased transvascular leak of 125I-labeled albumin into lungs and decreased lung ATP levels (P less than 0.05). In addition, rats subjected to intestinal I/R had increased plasma xanthine oxidase (XO) activity, plasma leukotactic activity for neutrophils, and lung neutrophil retention (assessed by morphometry and myeloperoxidase activity) compared with sham-treated rats (P less than 0.05). By comparison, after intestinal I/R, rats fed an allopurinol- or tungsten-enriched diet had decreased plasma and intestinal XO activities, decreased plasma leukotacic and lung myeloperoxidase (MPO) activities, decreased lung leak, and increased lung ATP levels compared with rats fed control diets (P less than 0.05). Further studies suggested a more specific role for circulating rather than tissue XO in mediating lung neutrophil accumulation but not lung leak. Plasma XO, plasma leukotactic, and lung MPO activities, but not lung leak, increased in rats administered purified XO intravenously. In addition, plasma XO, plasma leukotactic, and lung MPO activities, but not lung leak, decreased in rats administered antisera against XO and then subjected to intestinal I/R. We conclude that circulating XO increases acutely and may contribute to pulmonary retention of neutrophils after an ischemic intestinal insult.

Reperfusion of ischemic skeletal muscle causes erythrocyte hemolysis and decreases subsequent oxidant-mediated lung injury.

A prior transient hindlimb ischemia/reperfusion (I/R) insult decreased acute lung injury in rats subsequently treated with cobra venom factor. I/R-mediated protection was associated with erythrocyte hemolysis, increased plasma catalase activity, and increased plasma hydrogen peroxide scavenging activity. In contrast, hindlimb I/R did not increase lung catalase activity, and large amounts of injected catalase were required to increase lung catalase activity. The results suggest that limited I/R in one organ can induce systemic processes that may decrease a subsequent O2 metabolite-mediated injury in another distant organ. The mechanism may involve release of catalase from hemolyzed erythrocytes at levels that are not sufficient to measurably increase total lung catalase activity.

Existence and participation of xanthine oxidase in reperfusion injury of ischemic rabbit myocardium.

Using a highly specific assay that minimizes enzyme inactivation in vitro, we found that rabbit myocardial tissue contained low levels of xanthine oxidase (XO) and xanthine dehydrogenase (XD) activity that were effectively inhibited by pretreatment of hearts with allopurinol. In parallel, allopurinol treatment also improved ventricular developed pressure, peak systolic pressure, and coronary flow in isolated hearts subjected to 30 min of normothermic global ischemia and 30 min of reperfusion. Although function was protected by allopurinol treatment, creatine kinase (CK) release was not altered by allopurinol. Inhibition of myocardial XO with allopurinol did not increase myocardial ATP or phosphocreatine. In addition, allopurinol did not scavenge superoxide anion or hydrogen peroxide in vitro. The results support the possibility that relatively low amounts of XO activity, similar to levels reported in human myocardium, may contribute to cardiac ischemia-reperfusion injury.

Xanthine oxidase-derived H2O2 contributes to reperfusion injury of ischemic skeletal muscle.

We hypothesized that xanthine oxidase (XO)-derived hydrogen peroxide (H2O2) contributes to ischemic skeletal muscle injury during reperfusion. We found that after ischemia (3 h) and then reperfusion (4 h) rat gastrocnemius muscles had decreased contractile function following direct stimulation. Three lines of investigation suggested that XO-derived H2O2 contributes to reperfusion injury of ischemic skeletal muscle. First, treatment with dimethylthiurea (DMTU), a highly permeant O2 metabolite scavenger, but not urea, just before reperfusion improved muscle function in legs subjected to ischemia and then reperfusion. Second, gastrocnemius muscles from rats fed tungsten or allopurinol had negligible XO activities and increased muscle function after ischemia and reperfusion. Third, as assessed by measurement of skeletal muscle catalase activity in the presence of aminotriazole, H2O2 was measured during reperfusion of ischemic muscles from untreated or urea-treated rats but not during reperfusion of muscles from rats treated with DMTU, tungsten, or allopurinol.

Metals inhibit riboflavin-catalyzed generation of superoxide anion in vitro.

We found that addition of cationic metals inhibited flavin-catalyzed superoxide anion (O2-.) production in vitro. Inhibition of O2-. generation by metals appeared to relate to the ability of metal ions to chelate or complex with amine groups, altering their electronegativity. Metal inhibition of O2-. production has important implications for biological systems involving O2-. radical production, as well as for assays requiring the generation of O2-. in vitro.