[Show abstract][Hide abstract] ABSTRACT: With new drugs being introduced to treat asthma it is timely to review criteria that can be used to assess efficacy in clinical trials. Anti-asthma drugs are classified into symptoms-modifying, symptom preventers and disease modifying agents. Attention is drawn to the types of experimental evidence required in preclinical studies to support further clinical development of a new therapy. Clinical trials demand careful selection of patients to maximise the strength of the efficacy signal according to the type of trial being designed. While provocation tests are useful in suggesting efficacy, negative tests do not necessarily indicate lack of anti-asthma activity. Therapeutic trial designs need to take account of duration of treatment, dose-response relationships and confirmatory trials. Outcome measures include symptoms, lung function, reduction in concomitant medication, exacerbations, quality of life and measures of inflammation. Interpretation of results need to include the clinical relevance of any changes as well as statistical significance. Special consideration needs to be given to the evaluation of drugs for acute severe asthma, asthma in children and older people, co-morbidity such as rhinitis, and inhaler devices. As with all drugs introduced into practice, careful attention needs to be paid to both short- and long-term safety.
Full-text · Article · Jul 2004 · Respiratory Medicine
[Show abstract][Hide abstract] ABSTRACT: SCH351591, a novel phosphodiesterase-4 inhibitor under investigation as a potential therapeutic for asthma and chronic obstructive pulmonary disease (COPD), was evaluated in a 3-month rising-dose study in Cynomolgus monkeys. Four groups, containing four monkeys/sex, received vehicle control or rising doses up to 12, 24, or 48 mg/kg of SCH351591 daily. Although initial exposure produced clinical signs of emesis, reduced food intake, and reduced body weight, tachyphylaxis to the emesis allowed dose escalation up to 48 mg/kg/day. Two monkeys died and 3 were sacrificed in moribund condition over the course of the study. Early mortality, involving monkeys dosed with 12 or 24 mg/kg, was attributed to sepsis (2 monkeys) or colon inflammation (3 monkeys). Leukocyte function assays on low- and mid-dose group survivors revealed an inhibition of T lymphocyte proliferation for 12 mg/kg group males and 24 mg/kg group monkeys of both sexes. Necropsy findings, unassociated with early mortality, included reduced size and weight of the thymus, depletion of body fat, red discoloration of the gastric mucosa, and perivascular hemorrhage of the stomach and heart. Stomach and heart gross findings were present in the high-dose group only. Histopathologic lesions, in addition to those attributed to concurrent bacterial infection, included thymic atrophy, serous atrophy of fat, myocardial degeneration and acute to chronic inflammation of small to medium-sized arteries in various organs and tissues including the heart, kidneys, stomach, salivary glands, pancreas, esophagus, gallbladder, and mesentery. The findings of this study demonstrate the potential of a PDE4 inhibitor to alter immunologic response as well as to produce arteriopathy in nonhuman primates.
Full-text · Article · May 2004 · Toxicologic Pathology
[Show abstract][Hide abstract] ABSTRACT: Experiments were performed to characterize the pharmacology of SCH 206272 [(R,R)-1'[5-[(3,5-dichlorobenzoyl)methylamino]-3-(3,4-dichlorophenyl)-4(Z)-(methoxyimino)pentyl]-N-methyl-2-oxo-[1,4'bipiperidine]-3-acetamide] as a potent and selective antagonist of tachykinin (NK) NK(1), NK(2), and NK(3) receptors. SCH 206272 inhibited binding at human tachykinin NK(1), NK(2), and NK(3) receptors (K(i) = 1.3, 0.4, and 0.3 nM, respectively) and antagonized [Ca(2+)](i) mobilization in Chinese hamster ovary (CHO) cells expressing the cloned human tachykinin NK(1), NK(2), or NK(3) receptors. SCH 206272 inhibited relaxation of the human pulmonary artery (pK(b) = 7.7 +/- 0.3) induced by the tachykinin NK(1) receptor agonist, [Met-O-Me] substance P and contraction of the human bronchus (pK(b = 8.2 +/- 0.3) induced by the tachykinin NK(2) receptor agonist, neurokinin A. In isolated guinea pig tissues, SCH 206272 inhibited substance P-induced enhancement of electrical field stimulated contractions of the vas deferens, (pK(b = 7.6 +/- 0.2), NKA-induced contraction of the bronchus (pK(b) = 7.7 +/- 0.2), and senktide-induced contraction of the ileum. In vivo, oral SCH 206272 (0.1-10 mg/kg, p.o.) inhibited substance P-induced airway microvascular leakage and neurokinin A-induced bronchospasm in the guinea pig. In a canine in vivo model, SCH 206272 (0.1-3 mg/kg, p.o.) inhibited NK(1) and NK(2) activities induced by exogenous substance P and neurokinin A. Furthermore, in guinea pig models involving endogenously released tachykinins, SCH 206272 inhibited hyperventilation-induced bronchospasm, capsaicin-induced cough, and airway microvascular leakage induced by nebulized hypertonic saline. These data demonstrate that SCH 206272 is a potent, orally active tachykinin NK(1), NK(2), and NK(3) receptor antagonist. This compound may have beneficial effects in diseases thought to be mediated by tachykinins, such as cough, asthma, and chronic obstructive pulmonary disease.
No preview · Article · Sep 2002 · European Journal of Pharmacology
[Show abstract][Hide abstract] ABSTRACT: N-(3,5-Dichloro-1-oxido-4-pyridinyl)-8-methoxy-2-(trifluoromethyl)-5-quinoline carboxamide (SCH 351591) has been identified as a potent (IC(50) = 58 nM) and highly selective type 4 phosphodiesterase (PDE4) inhibitor with oral bioactivity in several animal models of lung inflammation. N-(3,5-Dichloro-4-pyridinyl)-8-methoxy-2-(trifluoromethyl)-5-quinoline carboxamide (SCH 365351), the only significant in vivo metabolite, is also a potent and highly selective PDE4 inhibitor (IC(50) = 20 nM). Both SCH 351591 and SCH 365351 inhibited cytokine production in human blood mononuclear cell preparations. Oral SCH 351591 significantly attenuated allergen-induced eosinophilia and airway hyperreactivity in allergic guinea pigs at doses as low as 1 mg/kg. In this model, oral SCH 365351 showed similar potency. When SCH 351591 was administered orally to allergic cynomolgus monkeys at 3 mg/kg, Ascaris suum-induced lung eosinophilia was blocked. Hyperventilation-induced bronchospasm in nonallergic guinea pigs, a model for exercise-induced asthma, was also suppressed significantly by oral SCH 351591 at 0.3 mg/kg. Cilomilast (SB 207499; Ariflo), a PDE4 inhibitor currently being developed for asthma and chronic obstructive pulmonary disease (COPD), was 10- to 30-fold less potent than SCH 351591 at inhibiting guinea pig lung eosinophilia and hyperventilation-induced bronchospasm. In a ferret model of emesis, maximum nonemetic oral doses of SCH 351591 and cilomilast were 5 and 1 mg/kg, respectively. Comparison of plasma levels at these nonemetic doses in ferrets to those at doses inhibiting hyperventilation-induced bronchospasm in guinea pigs gave a therapeutic ratio of 16 for SCH 351591 and 4 for cilomilast. Thus, SCH 351591 exhibits a promising preclinical profile as a treatment for asthma and COPD.
Preview · Article · Aug 2002 · Journal of Pharmacology and Experimental Therapeutics
[Show abstract][Hide abstract] ABSTRACT: Asthma is a common respiratory disorder characterized by recurrent episodes of coughing, wheezing and breathlessness. Although environmental factors such as allergen exposure are risk factors in the development of asthma, both twin and family studies point to a strong genetic component. To date, linkage studies have identified more than a dozen genomic regions linked to asthma. In this study, we performed a genome-wide scan on 460 Caucasian families and identified a locus on chromosome 20p13 that was linked to asthma (log(10) of the likelihood ratio (LOD), 2.94) and bronchial hyperresponsiveness (LOD, 3.93). A survey of 135 polymorphisms in 23 genes identified the ADAM33 gene as being significantly associated with asthma using case-control, transmission disequilibrium and haplotype analyses (P = 0.04 0.000003). ADAM proteins are membrane-anchored metalloproteases with diverse functions, which include the shedding of cell-surface proteins such as cytokines and cytokine receptors. The identification and characterization of ADAM33, a putative asthma susceptibility gene identified by positional cloning in an outbred population, should provide insights into the pathogenesis and natural history of this common disease.
[Show abstract][Hide abstract] ABSTRACT: The syntheses and pharmacological profiles of some 2-trifluoromethyl-8-methoxyquinoline-5-carboxamides are described. SCH351591 is a potent selective inhibitor of phosphodiesterase type 4 (PDE4).
[Show abstract][Hide abstract] ABSTRACT: Mast cell histamine (HA) and cysteinyl leukotrienes (CysLT) account for most of the early phase bronchospasm in asthma. However, activation of the smooth muscle CysLT1-receptor plays a major role in asthmatic bronchospasms. CysLT-receptor antagonists or CysLT-synthesis inhibitors are efficacious in asthma but do not completely abolish asthmatic bronchospasms. A recent clinical study showed that combined antagonists loratadine (H1) and zafirlukast (CysLT1) were more effective against allergic bronchospasms than either drug alone. We examined the combined efficacy of H1- and CysLT1-receptor antagonists in allergic human bronchus. The H1- and CysLT1-receptor antagonists chlorpheniramine (CTM; 1 microM) and MK-571 (0.03 microM), were tested alone and in combination, against anti-human IgE antibody (Ab)-induced contractions of passively sensitized isolated human bronchus. Ab-induced allergic contractions were reduced 15% and 36% by CTM (1 microM) and MK-571 (0.03 microM), respectively. Combined CTM (1 microM) and MK-571 (0.03 microM) significantly inhibited the Ab response by 87%. Mechanistic investigations in isolated human bronchus and cultured human cord blood mast cells suggest that H1- and CysLT-receptor interactions likely occur at the airway smooth muscle level. CTM and MK-571 synergistically inhibited human allergic bronchospasm in the present in vitro model. The mechanism underlying this synergistic activity requires further investigation.
[Show abstract][Hide abstract] ABSTRACT: We studied the central and peripheral antitussive effect of ORL1 receptor activation with nociceptin/orphanin FQ in conscious guinea-pigs. In guinea-pig cough studies, nociceptin/orphanin FQ (10, 30, and 90 μg) given directly into the CNS by an intracerebroventricular (i.c.v.) route inhibited cough elicited by capsaicin exposure by approximately 23, 29 and 52%, respectively. The antitussive activity of nociceptin/orphanin FQ (90 μg, i.c.v.) was blocked by the selective ORL1 antagonist [Phe1γ(CH2-NH)Gly2]nociceptin-(1-13)-NH2 (180 μg, i.c.v.) and J113397 (10 mg kg−1, i.p.) but not by the opioid antagonist, naltrexone (3 mg kg−1, i.p.). Furthermore, intravenous (i.v.) nociceptin/orphanin FQ (1.0 and 3.0 mg kg−1) also inhibited cough approximately by 25 and 42%, respectively. These findings indicate that selective ORL1 agonists display the potential to inhibit cough by both a central and peripheral mechanism, and potentially represent a novel therapeutic approach for the treatment of cough.
British Journal of Pharmacology (2001) 132, 1175–1178; doi:10.1038/sj.bjp.0703954
Full-text · Article · Apr 2001 · British Journal of Pharmacology
[Show abstract][Hide abstract] ABSTRACT: Interleukin-5 is produced by a number of cell types, and is responsible for the maturation and release of eosinophils in the bone marrow. In humans, interleukin-5 is a very selective cytokine as a result of the restricted expression of the interleukin-5 receptor on eosinophils and basophils. Eosinophils are a prominent feature in the pulmonary inflammation that is associated with allergic airway diseases, suggesting that inhibition of interleukin-5 is a viable treatment. The present review addresses the data that relate interleukin-5 to pulmonary inflammation and function in animal models, and the use of neutralizing anti-interleukin-5 monoclonal antibodies for the treatment of asthma in humans.
Full-text · Article · Feb 2001 · Respiratory Research
[Show abstract][Hide abstract] ABSTRACT: These studies were conducted to assess the systemic bioavailability of mometasone furoate (MF) administered by both the dry-powder inhaler (DPI) and the metered-dose inhaler with an alternate propellant (MDI-AP). The pharmacokinetics of single doses (400 micrograms) of MF administered by intravenous (i.v.) and inhalation routes was assessed in a randomized, three-way crossover study involving 24 healthy volunteers. In a separate study, 6 healthy subjects were administered a single dose of tritiated (3H-) MF by DPI, and the radioactivity in blood, urine, feces, and expired air was determined. Following i.v. administration, MF was detected in all subjects for at least 8 hours postdose. The half-life (t1/2) following i.v. administration was 4.5 hours. In contrast, following DPI administration, plasma MF concentrations were below the limit of quantification (LOQ, 50 pg/mL) for many subjects (10 of 24), and the systemic bioavailability by this route was estimated to be less than 1%. Only two plasma samples following MDI-AP administration had plasma concentrations of MF above the LOQ indicating no detectable systemic bioavailability in 92% of the subjects. A separate study with 6 healthy male subjects administered a single dose of 3H-MF (200 microCi) by DPI revealed that much of the dose (approximately 41%) was excreted unchanged in the feces (0-72 hours), while that which was absorbed was extensively metabolized. These results indicate that inhaled MF has negligible systemic bioavailability and is extensively metabolized and should therefore be well tolerated in the chronic treatment of asthma.
No preview · Article · Dec 2000 · The Journal of Clinical Pharmacology
[Show abstract][Hide abstract] ABSTRACT: A new formulation of mometasone furoate (MF) for administration by dry powder inhaler (DPI) was evaluated for the treatment of asthma. A 12-week, double-blind, placebo-controlled dose-ranging study compared the efficacy and safety of three doses of MF DPI (100, 200 and 400 mcg b.i.d) with beclomethasone dipropionate (BDP) 168 mcg b.i.d. administered by metered dose inhaler in 365 adult or adolescent patients being treated with inhaled glucocorticoids. The mean change from baseline to endpoint (last treatment visit) for forced expiratory volume in 1 sec (FEV1) was the primary efficacy variable. Secondary efficacy variables included other objective measures of pulmonary function [forced vital capacity (FVC), forced expiratory flow 25-75% (FEV25-75%.) and peak expiratory flow rate (PEFR)] as well as subjective measures of therapeutic response (patients' daily evaluation of asthma symptoms and physicians' evaluation). At endpoint, all four active treatments were significantly more effective than placebo (P < 0.01) in improving FEV1 (MF DPI 5 to 7%, BDP 3%, placebo -6.6%) and all other measures of pulmonary function (FVC: MF DPI 4 to 5%, BDP 2%, placebo -4.7%; FEF25-75%: MF DPI 6 to 18%, BDP 7.5%, placebo -9.5%; PEFR (AM): MF DPI 5 to 10%, BDP 5.7%, placebo -7%). A consistent trend was observed for better improvement in patients treated with MF DPI 200 mcg b.i.d. than with MF DPI 100 mcg b.i.d., with no apparent additional benefit of MF DPI 400 mcg b.i.d. Results for the MF DPI 100 mcg b.i.d. and BDP 168 mcg b.i.d. treatment groups were similar. Patients' and physicians' subjective evaluations of symptoms found similar improvement in the MF DPI 200 and 400 mcg b.i.d. treatment groups, which were slightly better than that in the MF DPI 100 mcg b.i.d. group. Symptoms tended to worsen in the placebo group. MF DPI was well tolerated at all dose levels and the most frequently reported treatment-related adverse effects were headache, pharyngitis and oral candidiasis. No evidence of HPA-axis suppression was detected in any treatment group. In summary, all doses of MF DPI were well tolerated and significantly improved lung function and MF DPI 400 mcg (200 mcg b.i.d.) was the optimal dose in this study of patients with moderate persistent asthma.
Full-text · Article · Sep 1999 · Respiratory Medicine
[Show abstract][Hide abstract] ABSTRACT: Many antihistamines exhibit inhibition of mediator release from mast cells and basophils, in in vitro studies in addition to H1 antagonism. The underlying mechanism is unclear but is unrelated to H1-receptor antagonism. Clinical studies of antihistamins in antigen challenge and seasonal allergy demonstrate reduction of mast cell mediators in nasal lavage. It is not known what mechanism(s) underly these observations, although the concentrations required in in vitro studies suggests that a direct effect on mast cells is unlikely. Furthermore, the therapeutic contribution of this effect is difficult to assess because of concomitant clinically significant H1 antagonism. This and other potential anti-allergic effects may enhance the therapeutic benefit of antihistamines and long-term studies are underway to explore this possibility.
No preview · Article · Aug 1999 · Clinical & Experimental Allergy
[Show abstract][Hide abstract] ABSTRACT: The extremely low reporting rate of cardiovascular adverse events for loratadine, the possible preferential use of loratadine in patients with pre-existing cardiovascular disorders, and the impressive lack of cardiovascular effects at extremely high concentrations in clinical and preclinical studies demonstrate the very safe cardiovascular profile of loratadine.
No preview · Article · Aug 1999 · Clinical & Experimental Allergy
[Show abstract][Hide abstract] ABSTRACT: IL-5 is a prominent and perhaps an essential element in the induction of allergic inflammation in human asthma and other allergic diseases. Despite the strong biochemical and clinical correlates between lung eosinophilia and asthma, there is no clear understanding of how eosinophils exacerbate asthma. Antigen administration to sensitized animals produces eosinophilic infiltration that is very similar to that in man, and is prevented by administration of a neutralizing monoclonal antibody against IL-5. Mice in which the IL-5 gene is absent are unable to mount eosinophilic responses to antigen and do not sustain lung damage, but otherwise develop normally. The study of the biology of IL-5 has not only clarified the links between eosinophilia and airway hyperreactivity, but also strongly suggests that anti-IL-5 therapy may be an effective, safe, and novel way of treating human asthma and perhaps other eosinophilic diseases. There are many different potential approaches to the inhibition of IL-5, but the one most likely to provide "proof of principle" in "asthma in the wild" in man is a monoclonal antibody against IL-5.
[Show abstract][Hide abstract] ABSTRACT: Study objective: To compare the efficacy and safety of a double-strength formulation of beclomethasone dipropionate (BDP 84) metered-dose inhaler (MDI) with that of beclomethasone dipropionate (BDP 42) MDI in the treatment of chronic asthma. Design: A 28-day, randomized, double-blind, double-dummy, placebo-controlled, multicenter study. Setting: Outpatient. Patients: A total of 423 patients aged 12 to 65 years (mean range, 34 to 36 years) with moderate asthma (FEV1, 50 to 80% of predicted) who required long-term inhaled corticosteroids were enrolled. Interventions: Patients were randomized to receive BDP 84, two oral inhalations bid (336 mu g/d), BDP 42, four oral inhalations bid (336 mu g/d), or placebo. A fourth treatment arm administering BDP 84, eight oral inhalations bid (HD BDP 84; 1,344 mu g/d) was also included to determine whether a close-response relationship could be demonstrated. Measurements: Spirometry, clinical observations. Results: The three active treatments were significantly more effective (p less than or equal to 0.01) than placebo at all time points in improving FEV1, the primary efficacy parameter; BDP 42 and BDP 84 were comparable to each other at every time point. Secondary pulmonary function tests (FVC, forced expiratory flow at 25 to 75% of FVC, and peak expiratory flow rate) showed similar results. All three active treatments were well tolerated. A dose response between 336 mu g/d and 1,344 mu g/d was demonstrated. Conclusion: in this well-controlled 28-day study, BDP 42 and BDP 84 were shown to be comparable in efficacy and safety on a microgram-for-microgram basis.