Safety, pharmacokinetics and dose-response characteristics of GSK2269557, an inhaled PI3Kδ inhibitor under development for the treatment of COPD.

BACKGROUND: While current therapies reduce symptoms in chronic obstructive pulmonary disease (COPD) patients, substantial unmet need remains and novel treatments are highly desired. Phosphoinositide 3-kinase δ (PI3Kδ) is a lipid kinase specifically expressed in leucocytes and involved in their recruitment and activation. This study evaluated the safety, pharmacokinetics (PK) and dose-response characteristics of inhaled GSK2269557, a PI3Kδ inhibitor, in moderate-to-severe COPD patients with stable disease. METHODS: In this randomised, double-blind, placebo controlled, parallel group study, patients received once daily inhaled treatment with GSK2269557 1000 µg or placebo for 14 days (Part A, primary aim safety, N = 28 patients). In part B of the study (primary aim pharmacodynamic dose-response, N = 36 patients), GSK2269557 100, 200, 500, 700, 1000, 2000 µg or placebo was given for 14 days. In both Part A and B, GSK2269557 was added to the usual maintenance therapy. Safety, PK assessments and induced sputum collection for cytokine analysis were conducted at baseline and after 7 and 14 days of treatment. Adverse events (AEs) were monitored throughout. RESULTS: In Part A, mean age was 61.7 years (SD 6.7), 29% were females, and mean FEV1% predicted was 59.7% (SD 11.4)2. In Part B, mean age was 63.3 years (SD 6.3), 44% were females, and mean FEV1% predicted was 56.5% (SD 11.5)2. GSK2269557 was well tolerated in both parts of the study; the most commonly reported AEs were cough and headache, with cough being reported with a greater incidence in the GSK2269557 groups vs. placebo (Part A: 19% vs. 14% and Part B: range of 0-80% for different doses vs. 0% on placebo). No drug-related serious AEs or clinically significant changes in any other safety parameters were reported. GSK2269557 was rapidly absorbed into plasma following all doses with a maximum peak at approximately 2 h. Following repeat administration, accumulation in plasma was approximately 2-3 fold from Day 1 to Day 7. At Day 14, relative to placebo, sputum interleukin (IL)-8 and IL-6 levels were reduced on average by 32% and 29% respectively after inhalation of GSK2269557 1000 µg in Part A. In Part B, although inhibition of both IL-8 and IL-6 levels was observed, the levels were variable and there was insufficient evidence to support a monotonic dose-response. CONCLUSIONS: In this study, inhaled GSK2269557 had an acceptable safety profile for progression into larger studies in COPD patients. Moreover, inhalation of GSK2269557 resulted in suppression of sputum IL-8 and IL-6 levels, consistent with the known anti-inflammatory activity of a PI3Kδ inhibitor. Inhibition of inflammatory cytokines in the airway compartment may contribute to the potential therapeutic benefit of a PI3Kδ inhibitor in chronically inflamed COPD patients.

Marked long-term decline in ambient CO mixing ratio in SE England, 1997-2014: evidence of policy success in improving air quality.

Atmospheric CO at Egham in SE England has shown a marked and progressive decline since 1997, following adoption of strict controls on emissions. The Egham site is uniquely positioned to allow both assessment and comparison of 'clean Atlantic background' air and CO-enriched air downwind from the London conurbation. The decline is strongest (approximately 50 ppb per year) in the 1997-2003 period but continues post 2003. A 'local CO increment' can be identified as the residual after subtraction of contemporary background Atlantic CO mixing ratios from measured values at Egham. This increment, which is primarily from regional sources (during anticyclonic or northerly winds) or from the European continent (with easterly air mass origins), has significant seasonality, but overall has declined steadily since 1997. On many days of the year CO measured at Egham is now not far above Atlantic background levels measured at Mace Head (Ireland). The results are consistent with MOPITT satellite observations and 'bottom-up' inventory results. Comparison with urban and regional background CO mixing ratios in Hong Kong demonstrates the importance of regional, as opposed to local reduction of CO emission. The Egham record implies that controls on emissions subsequent to legislation have been extremely successful in the UK.

The effect of phosphatidylinositol-3 kinase inhibition on matrix metalloproteinase-9 and reactive oxygen species release from chronic obstructive pulmonary disease neutrophils.

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD) is characterised by increased neutrophilic inflammation. A potential novel anti-inflammatory target in COPD is phosphatidylinositol-3 kinase (PI3 kinase), which targets neutrophil function. This study evaluated the effects of selective PI3Kδ inhibition on COPD blood and sputum neutrophils both in the stable state and during exacerbations. METHODS: Blood and sputum neutrophils from stable and exacerbating COPD patients were cultured with the corticosteroid dexamethasone, a pan PI3 kinase inhibitor (ZSTK474), a δ selective PI3 kinase inhibitor (GSK045) and a p38 mitogen activated protein (MAP) kinase inhibitor (BIRB 796); matrix metalloproteinase (MMP)-9 and reactive oxygen species (ROS) release were analysed. RESULTS: PI3Kδ inhibition significantly reduced MMP-9, intracellular ROS and extracellular ROS release from blood neutrophils (45.6%, 30.1% and 47.4% respectively; p<0.05) and intracellular ROS release from sputum neutrophils (16.6%; p<0.05) in stable patients. PI3Kδ selective inhibition significantly reduced stimulated MMP-9 (36.4%; p<0.05) and unstimulated and stimulated ROS release (12.6 and 26.7%; p<0.05) from blood neutrophils from exacerbating patients. The effects of the p38 MAP kinase inhibitor and dexamethasone in these experiments were generally lower than PI3Kδ inhibition. CONCLUSION: PI3Kδ selective inhibition is a potential strategy for targeting glucocorticoid insensitive MMP-9 and ROS secretion from COPD neutrophils, both in the stable state and during exacerbations.

Emission of methane from plants.

It has been proposed that plants are capable of producing methane by a novel and unidentified biochemical pathway. Emission of methane with an apparently biological origin was recorded from both whole plants and detached leaves. This was the first report of methanogenesis in an aerobic setting, and was estimated to account for 10-45 per cent of the global methane source. Here, we show that plants do not contain a known biochemical pathway to synthesize methane. However, under high UV stress conditions, there may be spontaneous breakdown of plant material, which releases methane. In addition, plants take up and transpire water containing dissolved methane, leading to the observation that methane is released. Together with a new analysis of global methane levels from satellite retrievals, we conclude that plants are not a major source of the global methane production.