Claire Ambery

Pharmacodynamics of GSK961081, a bi-functional molecule, in patients with COPD.

GSK961081 is an inhaled bi-functional molecule with both muscarinic antagonism and β2-agonism (MABA) properties. This randomised, double-blind, double-dummy, crossover study evaluated 14 days treatment with the MABA GSK961081 400 μg and 1200 μg once daily and tiotropium 18 μg once daily plus salmeterol 50 μg twice daily (TIO + SAL), versus placebo in 50 patients with moderate COPD. The primary endpoint was forced expiratory volume in 1 s (FEV1) at 24 h on Days 1 and 14. MABA 400 (n = 29), MABA 1200 (n = 32) and TIO + SAL (n = 41) resulted in significant increases in FEV1 over 24 h. Mean (95% CI) 24 h trough FEV1 (L) values relative to placebo (n = 43) were, for Day 1, MABA 400: 0.141 (0.060, 0.222); MABA 1200: 0.184 (0.105, 0.263); TIO + SAL: 0.162 (0.092, 0.231); for Day 14, MABA 400: 0.115 (0.024, 0.205); MABA 1200: 0.168 (0.080, 0.255); TIO + SAL: 0.103 (0.026, 0.180). Onset of bronchodilation was faster for both MABA doses versus TIO + SAL. No clinically relevant systemic pharmacodynamic effects were observed. Adverse events were similar across groups; however tremor (n = 2, MABA 1200), dysgeusia (n = 2, MABA 1200; n = 2, MABA 400) and dry mouth (n = 1, MABA 1200) were reported after GSK961081 only. GSK961081 demonstrated sustained bronchodilation similar to TIO + SAL, but with a more rapid onset, and was well tolerated at the tested doses.

The Efficacy and Tolerability of Two Novel H1/H3 Receptor Antagonists in Seasonal Allergic Rhinitis

Background: A therapeutic role for histamine H3 receptor antagonism in allergic rhinitis has been proposed and may be complimentary to the well-known benefits of H1 receptor antagonism. Combined H1/H3 blockade has therefore been investigated as a novel therapeutic approach that may enhance symptom relief, particularly nasal blockage. Methods: Two novel H1/H3 dual receptor antagonists were investigated in phase I and II safety and efficacy studies. One molecule (GSK1004723) was designed for intranasal administration as a suspension or solution and the other molecule (GSK835726) for oral administration. In phase I and II studies, both molecules were compared with an active control and/or placebo in randomised studies. In phase II studies, efficacy was assessed in an environmental allergen challenge chamber (ECC). Subjects with seasonal allergic rhinitis were exposed to allergen to induce symptoms. Efficacy and safety was measured over 4, 7 and 20–24 h post-dose. The endpoints included total nasal symptom score and nasal blockage. Results: Intranasal suspension of GSK1004723 and oral GSK835726 were well tolerated. Single-dose intranasal suspensions of GSK1004723 (220, 1,100 µg) failed to demonstrate clinically significant attenuation of symptoms of allergic rhinitis induced in the ECC. Single (10, 50, 100 mg) and 3-day repeat (10 mg) dose oral GSK835726 demonstrated clinically significant attenuation of symptoms in the ECC comparable to cetirizine 10 mg. Three-day repeat dosing of the intranasal solution GSK1004723 1,000 µg also demonstrated a statistically significant attenuation of nasal symptoms, but was less than seen with cetirizine and GSK835726 and caused initial nasal discomfort. Conclusions: Combined H1/H3 antagonism did not show differentiation from H1 antagonism in reducing total nasal symptom score or nasal blockage.

Pharmacodynamics, pharmacokinetics and safety of GSK2190915, a novel oral anti-inflammatory 5-lipoxygenase-activating protein inhibitor.

AIM To assess the pharmacokinetics, pharmacodynamics, safety and tolerability of the 5-lipoxygenase-activating protein inhibitor, GSK2190915, after oral dosing in two independent phase I studies, one in Western European and one in Japanese subjects, utilizing different formulations. METHOD Western European subjects received single (50-1000 mg) or multiple (10-450 mg) oral doses of GSK2190915 or placebo in a dose-escalating manner. Japanese subjects received three of four GSK2190915 doses (10-200 mg) plus placebo once in a four period crossover design. Blood samples were collected for GSK2190915 concentrations and blood and urine were collected to measure leukotriene B₄ and leukotriene E₄, respectively, as pharmacodynamic markers of drug activity. RESULTS There was no clear difference in adverse events between placebo and active drug-treated subjects in either study. Maximum plasma concentrations of GSK2190915 and area under the curve increased in a dose-related manner and mean half-life values ranged from 16-34 h. Dose-dependent inhibition of blood leukotriene B₄ production was observed and near complete inhibition of urinary leukotriene E₄ excretion was shown at all doses except the lowest dose. The EC₅₀ values for inhibition of LTB₄ were 85 nM and 89 nM in the Western European and Japanese studies, respectively. CONCLUSION GSK2190915 is well-tolerated with pharmacokinetics and pharmacodynamics in Western European and Japanese subjects that support once daily dosing for 24 h inhibition of leukotrienes. Doses of ≥50 mg show near complete inhibition of urinary leukotriene E₄ at 24 h post-dose, whereas doses of ≥150 mg are required for 24 h inhibition of blood LTB₄.

Effects of a FLAP inhibitor, GSK2190915, in asthmatics with high sputum neutrophils

Patients with refractory asthma frequently have neutrophilic airway inflammation and respond poorly to inhaled corticosteroids. This study evaluated the effects of an oral 5-lipoxygenase-activating protein (FLAP) inhibitor, GSK2190915, in patients with asthma and elevated sputum neutrophils. Patients received 14 (range 13-16) days treatment with GSK2190915 100 mg and placebo with a minimum 14 day washout in a double-blind, cross-over, randomised design (N = 14). Sputum induction was performed twice pre-dose in each treatment period to confirm sputum neutrophilia, and twice at the end of each treatment period. The primary endpoint was the percentage and absolute sputum neutrophil count, averaged for end-of-treatment visits. GSK2190915 did not significantly reduce mean percentage sputum neutrophils (GSK2190915-placebo difference [95% CI]: -0.9 [-12.0, 10.3]), or mean sputum neutrophil counts (GSK2190915/placebo ratio [95% CI]: 1.06 [0.43, 2.61]). GSK2190915 resulted in a marked suppression (>90%) of sputum LTB4 and urine LTE4, but did not alter clinical endpoints. There were no safety issues. Despite suppressing the target mediator LTB4, FLAP inhibitor GSK2190915 had no short-term effect on sputum cell counts or clinical endpoints in patients with asthma and sputum neutrophilia.

Bronchodilation and safety of supratherapeutic doses of salbutamol or ipratropium bromide added to single dose GSK961081 in patients with moderate to severe COPD

BACKGROUND There are few data on the bronchodilatory effects of adding short-acting bronchodilators (SABA) to maintenance, long-acting bronchodilator therapy. This study assessed the additional bronchodilation and safety of adding supratherapeutic doses of salbutamol (SALB) or ipratropium bromide (IPR) to the novel bi-functional molecule (or dual pharmacophore) GSK961081 400 μg (MABA 400) or 1200 μg (MABA 1200). METHODS This randomised, double-blind, complete, crossover study in 44 patients with moderate to severe COPD, evaluated 6 treatments with a washout of at least 7 days between treatments: single doses of MABA 400 or MABA 1200 followed by cumulative doses of either SALB (3× 200 μg at 20 min intervals), IPR (20 μg, 20 μg and 40 μg at 20 min intervals) or placebo (PLA) (three doses at 20 min intervals) at 1 h, 12 h and 24 h post-MABA dose. The primary endpoint was maximal increase in FEV1, from pre-dose bronchodilator (SABA/PLA), measured 15 min after each cumulative dose of SALB, IPR or PLA. Systemic pharmacodynamics (potassium, heart rate, glucose and QTc), adverse events and systemic pharmacokinetics were also assessed. RESULTS The additional bronchodilatory effects at 12 h and 24 h for both SALB and IPR were of a similar magnitude and statistically significant relative to PLA; mean differences (SE) (L) following MABA 400 dosing: 0.139 (0.023) after SALB at 12 h; 0.123 (0.022) after SALB at 24 h; 0.124 (0.023) after IPR at 12 h; 0.141 (0.021) after IPR at 24 h; and after MABA 1200 dosing: 0.091 (0.023) after SALB at 12 h; 0.126 (0.022) after SALB at 24 h; 0.055 (0.023) after IPR at 12 h; 0.122 (0.022) after IPR at 24 h. Any additional bronchodilator effects at 1 h were small and not clinically significantly different from PLA. There were small, non-clinically significant increases in mean heart rate after both MABA doses plus SALB, and decreased potassium levels in four patients after MABA 1200 plus SALB (×3) or PLA (×1) were observed but overall all treatments were well tolerated and raised no significant safety signals. CONCLUSION The additional bronchodilation achieved following supratherapeutic doses of SALB and IPR on top of single doses of MABA 400 or 1200 was comparable for the two agents and neither were associated with any clinically relevant systemic pharmacodynamic effects other than the small transient hypokalemic effect in a 3 out of 41 patients receiving additional high dose salbutamol and MABA 1200. Either short-acting bronchodilator could potentially be used as rescue medication on top of MABA therapy.

Open‐Label, Randomized, 6‐Way Crossover, Single‐Dose Study to Determine the Pharmacokinetics of Batefenterol (GSK961081) and Fluticasone Furoate When Administered Alone or in Combination

To investigate the pharmacokinetics of inhaled batefenterol (BAT) and fluticasone furoate (FF) given alone or in combination via ELLIPTA® dry powder inhaler (DPI‐E), and BAT monotherapy via DISKUS® DPI (DPI‐D). In this open‐label, 6‐way crossover study, 48 healthy subjects were randomized to 1 of 6 treatment sequences, comprising 6 single‐dose treatment regimens: (1) BAT 1200 μg via DPI‐D; (2) BAT 1200 μg via DPI‐E without a lactose‐filled second strip; (3) BAT 1200 μg via DPI‐E with a lactose‐filled second strip; (4) BAT/FF 1200/300 μg via DPI‐E; (5) FF 300 μg via DPI‐E with a lactose‐filled second strip; and (6) BAT/FF 900/300 μg via DPI‐E. Pharmacokinetic data were analyzed using noncompartmental methods. Plasma BAT area under the curve (AUC) and maximum plasma concentration (Cmax) were similar for all treatments containing BAT 1200 μg (geometric least‐squares means [GLSM] ratio, 0.90–1.06). Plasma FF AUC and Cmax were reduced following BAT/FF 1200/300 μg and 900/300 μg versus FF 300 μg monotherapy (GLSM ratio, 0.62–0.77). BAT 1200 μg administered via DPI‐E, alone or in combination with FF, resulted in similar systemic exposure versus BAT administered by DPI‐D. FF exposure was reduced when administered in combination with BAT compared with FF alone.

Pharmacokinetics and pharmacodynamics of GSK961081, a novel inhaled muscarinic antagonist β2-agonist, and fluticasone propionate administered alone, concurrently and as a combination blend formulation in healthy volunteers

To investigate the pharmacokinetics and pharmacodynamics of inhaled GSK961081 and fluticasone propionate (FP) given alone, concurrently and as a combination blend formulation.

Comparing probabilistic and descriptive analyses of time-dose-toxicity relationship for determining no-observed-adverse-effect level in drug development.

The no-observed-adverse-effect level (NOAEL) of a drug defined from animal studies is important for inferring a maximal safe dose in human. However, several issues are associated with its concept, determination and application. It is confined to the actual doses used in the study; becomes lower with increasing sample size or dose levels; and reflects the risk level seen in the experiment rather than what may be relevant for human. We explored a pharmacometric approach in an attempt to address these issues. We first used simulation to examine the behaviour of the NOAEL values as determined by current common practice; and then fitted the probability of toxicity as a function of treatment duration and dose to data collected from all applicable toxicology studies of a test compound. Our investigation was in the context of an irreversible toxicity that is detected at the end of the study. Simulations illustrated NOAELs dependency on experimental factors such as dose and sample size, as well as the underlying uncertainty. Modelling the probability as a continuous function of treatment duration and dose simultaneously to data from multiple studies allowed the estimation of the dose, along with its confidence interval, for a maximal risk level that might be deemed as acceptable for human. The model-based data integration also reconciled between-study inconsistency and explicitly provided maximised estimation confidence. Such alternative NOAEL determination method should be explored for its more efficient data use, more quantifiable insight to toxic doses, and the potential for more relevant animal-to-human translation.

Identification and characterisation of a salt form of Danirixin with reduced pharmacokinetic variability in patient populations

Graphical abstract Figure. No caption available. ABSTRACT The natural variability of gastric pH or gastric acid reducing medications can result in lower and more variable clinical pharmacokinetics for basic compounds in patient populations. Progressing alternative salt forms with improved solubility and dissolution properties can minimise this concern. This manuscript outlines a nonclinical approach comprising multiple biopharmaceutical, in vitro and physiologically based pharmacokinetic model (PBPK) modelling studies to enable selection of an alternative salt form for danirixin (DNX, GSK1325756), a pharmaceutical agent being developed for chronic obstructive pulmonary disease (COPD). The hydrobromide salt of DNX was identified as having superior biopharmaceutical properties compared to the free base (FB) form in clinical development and the impact of switching to the hydrobromide salt (HBr) was predicted by integrating the nonclinical data in a PBPK model (using GastroPlus™) to enable simulation of clinical drug exposure with FB and HBr salts in the absence and presence of a gastric acid reducing comedication (omeprazole, a proton pump inhibitor (PPI)). Subsequent investigation of DNX pharmacokinetics in a Phase 1 clinical study comparing FB with HBr salt forms confirmed that DNX HBr had reduced the variability of drug exposure and that exposure was not affected by PPI co‐administration with DNX HBr. This case study therefore adds to the surprisingly few examples of a more soluble salt of a weak base translating to an improvement in human pharmacokinetics and illustrates a clear clinical benefit of salt selection during drug development.

Time-to-Event Modeling of Left- or Right-Censored Toxicity Data in Nonclinical Drug Toxicology

A time-to-event (TTE) model has been developed to characterize a histopathology toxicity that can only be detected at the time of animal sacrifice. The model of choice was a hazard model with a Weibull distribution and dose was a significant covariate. The diagnostic plots showed a satisfactory fit of the data, despite the high degree of left and right censoring. Comparison to a probabilistic logit model shows similar performance in describing the data with a slight underestimation of survival by the Logit model. However, the TTE model was found to be more predictive in extrapolating toxicity risk beyond the observation range of a truncated dataset. The diagnostic and comparison outcomes would suggest using the TTE approach as a first choice for characterizing short and long-term risk from nonclinical toxicity studies. However, further investigations are needed to explore the domain of application of this kind of approach in drug safety assessment.