Intradermal substance P as a challenge agent in healthy individuals.

Pharmacological challenge models are deployed to evaluate drug effects during clinical development. Intradermal injection of Substance P (SP) neuropeptide, a potential challenge agent for investigating local mediators, is associated with wheal and flare response mediated by the MRGPRX2 receptor. Although dose-dependent data on SP effects exist, full characterization and information on potential carryover effect after repeated challenge are lacking. This open-label, two-part, prospective enabling study of SP intradermal challenge in healthy participants aimed to understand and distinguish between wheal and flare responses following various SP doses. Part 1 included one challenge visit to determine optimum SP dose range for evaluation in part 2, which determined variability in 20 participants and used intradermal microdialysis (IDM) for SP-challenged skin sampling. At 5, 15, 50, and 150 pmol doses, respectively, posterior median area under the curve (AUC; AUC0-2h ) was 4090.4, 5881.2, 8846.8, and 9212.8 mm2 /min, for wheal response, and 12020.9, 38154.3, 65470.6, and 67404.4 mm2 /min for flare response (SP-challenge visit 2). When the challenge was repeated ~2 weeks later, no carryover effect was observed. IDM histamine levels were relatively low, resulting in low confidence in the data to define temporal characteristics for histamine release following SP challenge. No safety concerns were identified using SP. Wheal and flare responses following intradermal SP challenge were dose-dependent and different. The results indicate that this challenge model is fit-for-purpose in future first-in-human studies and further assessment of novel drugs targeting dermal inflammatory disease responses, such as chronic spontaneous urticaria, chronic inducible urticaria, and pseudo-allergic reactions.

First-in-Human Pharmacokinetics and Safety Study of GSK3008356, a Selective DGAT1 Inhibitor, in Healthy Volunteers.

Diacylglycerol acyltransferase (DGAT) enzymes are involved in triglyceride (TG) biosynthesis. GSK3008356 is a potent and selective DGAT1 inhibitor that was administered orally in a 2-part study as double-blind, randomized, placebo-controlled single doses (SDs) and repeat doses (RDs) in healthy subjects to investigate its pharmacokinetics, pharmacodynamics, and safety/tolerability. Gastrointestinal adverse events were considered drug related and increased with dose and when given as multiple doses. In the SD part (n = 80), GSK3008356 was dosed from 5 to 200 mg as single or multiple doses per day. In the RD part (n = 24), GSK3008356 was dosed twice daily at 1, 3, and 10 mg for 14 days. GSK3008356 was generally well tolerated in the SD and RD parts. With single doses, absorption was rapid (median tmax , 0.5-1.5 hours), whereas single-day divided dosing resulted in higher tmax . Following 14-day RD oral administration, GSK3008356 was also rapidly absorbed, with median tmax ranging from 0.5 to 0.75 hours on days 1 and 14. Estimated mean half-life ranged from 1.5 to 4.6 hours with SDs and 1.3 to 2.1 hours with RDs. Exposure of GSK3008356 was largely dose proportional after RDs. At higher doses, there was a trend toward lower absolute postprandial TG level in some subjects.

A population analysis of the DGAT1 inhibitor GSK3008356 and its effect on endogenous and meal-induced triglyceride turnover in healthy subjects.

Non-alcoholic steatohepatitis (NASH) is a liver disease in which fatty infiltration is accompanied by liver inflammation. GSK3008356 is under development as a selective inhibitor of diacylglycerol acyltransferase 1 (DGAT1), a key enzyme involved in the formation of triglyceride (TG). Decreased DGAT1 activity can reduce circulating TG and liver TG, and therefore could potentially prevent or treat NASH. The aim of the current study was to develop a population pharmacokinetic-pharmacodynamic (PKPD) model that characterizes the PK disposition of GSK3008356 and its relation to the changes in blood TG. Drug concentrations were measured in 104 healthy adults receiving various single (SD) and repeat doses (RD) in a first time in human (FiH) study. A 30% fat meal was given at hour 2 postdose, and blood postprandial TG concentrations were measured at various time points. The population PKPD model consists of several parts including a PK model, drug effect model, meal effect model, and a turnover model. The pharmacokinetic data were described using a 3-compartment model. Drug effect was described by an inhibitory sigmoidal Emax model. Since TG levels change with the introduction of a meal, a bi-exponential meal effect model was utilized. The total change in TG was fitted using a turnover model with drug and meal effects on the TG production rate. The current analysis presents a PKPD modeling strategy of time-varying TG data coming from both endogenous and exogenous sources. In general, the presented model could be utilized in the model-based drug development of drugs that influence TG levels in blood.

A Phase 1 Randomized, Placebo-Controlled Trial With a Topical Inhibitor of Stearoyl-Coenzyme A Desaturase 1 Under Occluded and Nonoccluded Conditions.

Stearoyl-coenzyme A desaturase 1 (SCD-1) in sebaceous glands is a key enzyme in the synthesis of monounsaturated fatty acids essential for acne development. GSK1940029 gel, a novel SCD-1 inhibitor, is being developed as a potential treatment for acne. To assess the irritation potential, pharmacokinetics (PK), and safety of topical GSK1940029 to the skin of healthy adults, two interdependent studies were conducted in parallel. Study 1 (n = 54) investigated the irritation potential of GSK1940029 (0.3% and 1%, occluded application) to allow for its application to larger surface areas in study 2 (n = 39), which investigated the safety, tolerability, and PK of GSK1940029 after single and repeat doses as occluded and nonoccluded applications. GSK1940029 was not a primary or cumulative irritant after 2 and 21 days of dosing in study 1. In study 2, single and repeat applications of GSK1940029 (0.1% to 1%) doses were well tolerated with little or no influence on AUC and Cmax under occluded or unoccluded conditions. Systemic exposure increased proportionally with surface area and was higher in occluded conditions. Design of these interdependent studies allowed for the assessment of the irritation potential for topical GSK1940029 in parallel with the investigation of PK and safety profiles.

A Novel Hypoxia-Inducible Factor-Prolyl Hydroxylase Inhibitor (GSK1278863) for Anemia in CKD: A 28-Day, Phase 2A Randomized Trial.

BACKGROUND: Anemia associated with chronic kidney disease (CKD) often requires treatment with recombinant human erythropoietin (EPO). Hypoxia-inducible factor-prolyl hydroxylase inhibitors (PHIs) stimulate endogenous EPO synthesis and induce effective erythropoiesis by non-EPO effects. GSK1278863 is an orally administered small-molecule PHI. STUDY DESIGN: Multicenter, single-blind, randomized, placebo-controlled, parallel-group study. SETTING & PARTICIPANTS: Anemic non-dialysis-dependent patients with CKD stages 3-5 (CKD-3/4/5 group; n=70) and anemic hemodialysis patients with CKD stage 5D (CKD-5D group; n=37). INTERVENTIONS: Patients with CKD-3/4/5 received placebo or GSK1278863 (10, 25, 50, or 100mg), and patients with CKD-5D received placebo or GSK1278863 (10 or 25mg) once daily for 28 days. OUTCOMES & MEASUREMENTS: Primary pharmacokinetic and pharmacodynamic (increase and response rates in achieving the target hemoglobin [Hb] concentration, plasma EPO concentrations, reticulocyte count, and others]) and safety and tolerability end points were obtained. RESULTS: Both CKD-3/4/5 and CKD-5D populations showed a dose-dependent increase in EPO concentrations and consequent increases in reticulocytes and Hb levels. Percentages of GSK1278863 participants with an Hb level increase > 1.0g/dL (CKD-3/4/5) and >0.5g/dL (CKD-5D) were 63% to 91% and 71% to 89%, respectively. Per-protocol-defined criteria, high rate of increase in Hb level, or high absolute Hb value was the main cause for withdrawal (CKD-3/4/5, 30%; CKD-5D, 22%). A dose-dependent decrease in hepcidin levels and increase in total and unsaturated iron binding were observed in all GSK1278863-treated patients. LIMITATIONS: Sparse pharmacokinetic sampling may have limited covariate characterization. EPO concentrations at the last pharmacodynamic sample (5-6 hours) postdose may not represent peak concentrations, which occurred 8 to 10 hours postdose in previous studies. Patients were not stratified by diabetes status, potentially confounding vascular endothelial growth factor and glucose analyses. CONCLUSIONS: GSK1278863 induced an effective EPO response and stimulated non-EPO mechanisms for erythropoiesis in anemic non-dialysis-dependent and dialysis-dependent patients with CKD.

Intravenous Pharmacokinetics, Local Tolerability, and Hemolysis of an SBE7-ß-Cyclodextrin Formulation of the Neurokinin-1 Receptor Antagonist Vestipitant.

Vestipitant is a potent and selective neurokinin 1 (NK-1) receptor antagonist that was investigated as a potential treatment for post-operative nausea and vomiting (PONV). A previous mannitol-based formulation of vestipitant was associated with hemolytic activity in preclinical studies. In an effort to reduce the hemolytic potential and develop an IV formulation of vestipitant that could be administered more rapidly, an IV formulation containing sulfobutylether-7-beta-cyclodextrin (SBE7-ß-CD, Captisol™) was developed and tested in a phase 1 clinical study. This was a randomized, single-blind (subjects and investigator-blinded, sponsor-unblinded), placebo controlled, dose escalation study in healthy subjects in which 7 cohorts of 8 subjects per cohort received SBE7-ß-CD -based vestipitant (2 mg/mL) or placebo (saline) in a 3:1 ratio (active:placebo) at different doses and infusion rates. The results demonstrated the ability to infuse up to 48 mg vestipitant in a 2 mg/mL formulation over 30 seconds with no evidence of hemolytic effects. Cohorts of subjects at lower doses and longer infusion duration (>1 minute) reported more AEs related to the infusion site than those at the higher doses and faster infusion rates.

The novel AKT inhibitor afuresertib shows favorable safety, pharmacokinetics, and clinical activity in multiple myeloma.

The PI3K/AKT pathway is constitutively active in hematologic malignancies, providing proliferative and antiapoptotic signals and possibly contributing to drug resistance. We conducted an open-label phase 1 study to evaluate the maximum tolerated dose (MTD), safety, pharmacokinetics, and clinical activity of afuresertib-an oral AKT inhibitor-in patients with advanced hematologic malignancies. Seventy-three patients were treated at doses ranging from 25 to 150 mg per day. The MTD was established at 125 mg per day because of 2 dose-limiting toxicities in the 150-mg cohort (liver function test abnormalities). The most frequent adverse events were nausea (35.6%), diarrhea (32.9%), and dyspepsia (24.7%). Maximum plasma concentrations and area under the plasma concentration-time curves from time 0 to 24 hours were generally dose proportional at > 75-mg doses; the median time to peak plasma concentrations was 1.5 to 2.5 hours post dose, with a half-life of approximately 1.7 days. Three multiple myeloma patients attained partial responses; an additional 3 attained minimal responses. Clinical activity was also observed in non-Hodgkin lymphoma, Langerhan's cell histiocytosis, and Hodgkin disease. Single-agent afuresertib showed a favorable safety profile and demonstrated clinical activity against hematologic malignancies, including multiple myeloma.

Farglitazar lacks antifibrotic activity in patients with chronic hepatitis C infection.

BACKGROUND & AIMS: Farglitazar (GI262570), an insulin-sensitizing agent, selectively binds and activates peroxisome proliferator-activated receptor gamma (PPARgamma) and inhibits stellate cell activation. We evaluated its antifibrotic effect in patients with chronic hepatitis C that did not respond to standard-of-care therapy. METHODS: Patients with fibrosis of Ishak stages 2-4 (n = 265), based on analysis of liver biopsy samples, were randomly assigned to groups given once-daily doses of 0.5 mg farglitazar, 1.0 mg farglitazar, or placebo for 52 weeks; repeat liver biopsy samples were then obtained. The primary end points were changes in levels of alpha-smooth muscle actin (SMA) expression and collagen, based on morphometry and ranked histologic assessments. RESULTS: Two hundred nine patients had paired biopsy specimens adequate for analysis (81.5% with pretreatment Ishak scores of stage 2 or 3). There was no overall difference in SMA (P = .58) or collagen (P = .99) levels at week 52. SMA levels increased by a median of 49% in samples from patients given placebo, 58% in patients given 0.5 mg farglitizar and 52% in patients given 1.0 mg farglitizar, respectively. Collagen increased by 27% in placebo samples and 31% in samples from patients given either dose of farglitizar. There were no significant differences between treatment groups in the ranked assessment of paired biopsy specimens or in the proportion of patients with a change in fibrosis score > or = Ishak stage. CONCLUSIONS: In patients with chronic hepatitis C and moderate fibrosis, 52 weeks of treatment with farglitazar does not affect stellate cell activation or fibrosis (measured by morphometry or comparison of paired biopsy specimens).

Synthesis, antimalarial activity, and preclinical pharmacology of a novel series of 4'-fluoro and 4'-chloro analogues of amodiaquine. Identification of a suitable "back-up" compound for N-tert-butyl isoquine.

On the basis of a mechanistic understanding of the toxicity of the 4-aminoquinoline amodiaquine (1b), three series of amodiaquine analogues have been prepared where the 4-aminophenol "metabolic alert" has been modified by replacement of the 4'-hydroxy group with a hydrogen, fluorine, or chlorine atom. Following antimalarial assessment and studies on mechanism of action, two candidates were selected for detailed ADME studies and in vitro and in vivo toxicological assessment. 4'-Fluoro-N-tert-butylamodiaquine (2k) was subsequently identified as a candidate for further development studies based on potent activity versus chloroquine-sensitive and resistant parasites, moderate to excellent oral bioavailability, low toxicity in in vitro studies, and an acceptable safety profile.

Candidate selection and preclinical evaluation of N-tert-butyl isoquine (GSK369796), an affordable and effective 4-aminoquinoline antimalarial for the 21st century.

N-tert-Butyl isoquine (4) (GSK369796) is a 4-aminoquinoline drug candidate selected and developed as part of a public-private partnership between academics at Liverpool, MMV, and GSK pharmaceuticals. This molecule was rationally designed based on chemical, toxicological, pharmacokinetic, and pharmacodynamic considerations and was selected based on excellent activity against Plasmodium falciparum in vitro and rodent malaria parasites in vivo. The optimized chemistry delivered this novel synthetic quinoline in a two-step procedure from cheap and readily available starting materials. The molecule has a full industry standard preclinical development program allowing first into humans to proceed. Employing chloroquine (1) and amodiaquine (2) as comparator molecules in the preclinical plan, the first preclinical dossier of pharmacokinetic, toxicity, and safety pharmacology has also been established for the 4-aminoquinoline antimalarial class. These studies have revealed preclinical liabilities that have never translated into the human experience. This has resulted in the availability of critical information to other drug development teams interested in developing antimalarials within this class.

Emerging therapeutic targets in psoriasis.

Biopharmaceuticals that target specific disease-mediating molecules have advanced our understanding of the pathogenesis of psoriasis. The traditional paradigm that psoriasis is primarily a disease of epidermal cells has been replaced with a model that now includes keratinocyte-derived factors, inflammatory mediators and angiogenic mechanisms. Recent studies have highlighted some of the key molecules involved in all of these pathogenic processes. Several have already been evaluated as putative targets in in vitro and in vivo studies, whereas other molecules are significantly upregulated in psoriasis and require further study to elucidate their role and contribution to disease. Although not all these molecules will eventually qualify as drug targets, data from similar experimental strategies are predicted to underpin the next generation of candidate targets and novel therapeutic approaches.