ABSTRACT
RATIONALE: Patients with asthma demonstrate depletion of the endogenous bronchodilator GSNO and upregulation of GSNOR. OBJECTIVES: An exploratory proof of concept clinical study of N6022 in mild asthma to determine the potential bronchoprotective effects of GSNOR inhibition. Mechanistic studies aimed to provide translational evidence of effect. METHODS: Fourteen mild asthma patients were treated with intravenous N6022 (5 mg) or placebo and observed for 7 days, with repeated assessments of the provocative dose of methacholine causing a 20% fall in FEV1 (methacholine PC20 FEV1), followed by a washout period and crossover treatment and observation. In vitro studies in isolated eosinophils investigated the effect of GSNO and N6022 on apoptosis. MEASUREMENTS AND MAIN RESULTS: This was a negative trial as it failed to reach its primary endpoint, which was change from baseline in methacholine PC20 FEV1 at 24 h. However, our exploratory analysis demonstrated significantly more two dose-doubling increases in PC20 FEV1 for N6022 compared with placebo (21% vs 6%, P < 0.05) over the 7-day observation period. Furthermore, a significant treatment effect was observed in the change in PC20 FEV1 from baseline averaged over the 7-day observation period (mean change: +0.82 mg/ml [N6022] from 1.34 mg/ml [baseline] vs -0.18 mg/ml [placebo] from 1.16 mg/ml [baseline], P = 0.023). N6022 was well tolerated in mild asthmatics. In vitro studies demonstrated enhanced eosinophilic apoptosis with N6022. CONCLUSIONS: In this early phase exploratory proof of concept trial in asthma, N6022 did not significantly alter methacholine PC20 FEV1 at 24 h, but did have a treatment effect at 7 days compared to baseline. Further investigation of the efficacy of S-nitrosoglutathione reductase inhibition in a patient population with eosinophilic asthma is warranted.
Subject(s)
Aldehyde Oxidoreductases/antagonists & inhibitors , Asthma/drug therapy , Benzamides/therapeutic use , Bronchial Hyperreactivity/drug therapy , Pyrroles/therapeutic use , Administration, Intravenous , Adult , Aldehyde Oxidoreductases/metabolism , Asthma/diagnosis , Asthma/immunology , Asthma/physiopathology , Bronchial Hyperreactivity/diagnosis , Bronchial Hyperreactivity/immunology , Bronchial Hyperreactivity/physiopathology , Bronchial Provocation Tests/methods , Bronchoconstrictor Agents/administration & dosage , Bronchoconstrictor Agents/immunology , Cross-Over Studies , Double-Blind Method , Female , Forced Expiratory Volume , Humans , Male , Methacholine Chloride/administration & dosage , Methacholine Chloride/immunology , Middle Aged , Placebos/administration & dosage , Proof of Concept Study , S-Nitrosoglutathione/immunology , S-Nitrosoglutathione/metabolism , Treatment Outcome , Young AdultABSTRACT
BACKGROUND: Cavosonstat (N91115), an orally bioavailable inhibitor of S-nitrosoglutathione reductase, promotes cystic fibrosis transmembrane conductance regulator (CFTR) maturation and plasma membrane stability, with a mechanism of action complementary to CFTR correctors and potentiators. METHODS: A Phase I program evaluated pharmacokinetics, drug-drug interactions and safety of cavosonstat in healthy and cystic fibrosis (CF) subjects homozygous for F508del-CFTR. Exploratory outcomes included changes in sweat chloride in CF subjects. RESULTS: Cavosonstat was rapidly absorbed and demonstrated linear and predictable pharmacokinetics. Exposure was unaffected by a high-fat meal or rifampin-mediated effects on drug metabolism and transport. Cavosonstat was well tolerated, with no dose-limiting toxicities or significant safety findings. At the highest dose, significant reductions from baseline in sweat chloride were observed (-4.1mmol/L; P=0.032) at day 28. CONCLUSIONS: The favorable safety and clinical profile warrant further study of cavosonstat in CF. ClinicalTrials.gov Numbers: NCT02275936, NCT02013388, NCT02500667.
