Incidence, Risk Factors, and Clinical Consequence of Enteral Feeding Intolerance in the Mechanically Ventilated Critically Ill: An Analysis of a Multicenter, Multiyear Database.

OBJECTIVES: To determine the incidence of enteral feed intolerance, identify factors associated with enteral feed intolerance, and assess the relationship between enteral feed intolerance and key nutritional and clinical outcomes in critically ill patients. DESIGN: Analysis of International Nutrition Survey database collected prospectively from 2007 to 2014. SETTING: Seven-hundred eighty-five ICUs from around the world. PATIENTS: Mechanically ventilated adults with ICU stay greater than or equal to 72 hours and received enteral nutrition during the first 12 ICU days. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: We defined enteral feed intolerance as interrupted feeding due to one of the following reasons: high gastric residual volumes, increased abdominal girth, distension, subjective discomfort, emesis, or diarrhea. The current analysis included 15,918 patients. Of these, 4,036 (24%) had at least one episode of enteral feed intolerance. The enteral feed intolerance rate increased from 1% on day 1 to 6% on days 4 and 5 and declined daily thereafter. After controlling for site and patient covariates, burn (odds ratio 1.46; 95% CIs, 1.07-1.99), gastrointestinal (odds ratio 1.45; 95% CI, 1.27-1.66), and sepsis (odds ratio 1.34; 95% CI, 1.17-1.54) admission diagnoses were more likely to develop enteral feed intolerance, as compared to patients with respiratory-related admission diagnosis. enteral feed intolerance patients received about 10% less enteral nutrition intake, as compared to patients without enteral feed intolerance after controlling for important covariates including severity of illness. Enteral feed intolerance patients had fewer ventilator-free days and longer ICU length of stay time to discharge alive (all p < 0.0001). The daily mortality hazard rate increased by a factor of 1.5 (1.4-1.6; p < 0.0001) once enteral feed intolerance occurred. CONCLUSIONS: Enteral feed intolerance occurs frequently during enteral nutrition delivery in the critically ill. Burn and gastrointestinal patients had the highest risk of developing enteral feed intolerance. Enteral feed intolerance is associated with lower enteral nutrition delivery and worse clinical outcomes. Identification, prevention, and optimal management of enteral feed intolerance may improve nutrition delivery and clinical outcomes in important "at risk" populations.

Effect of ileal bile acid transporter inhibitor GSK2330672 on pruritus in primary biliary cholangitis: a double-blind, randomised, placebo-controlled, crossover, phase 2a study.

BACKGROUND: Up to 70% of patients with primary biliary cholangitis develop pruritus (itch) during the course of their disease. Treatment of pruritus in primary biliary cholangitis is challenging and novel therapies are needed. Ursodeoxycholic acid, the standard first-line treatment for primary biliary cholangitis, is largely ineffective for pruritus. We investigated the efficacy and safety of GSK2330672, a selective inhibitor of human ileal bile acid transporter (IBAT), in patients with primary biliary cholangitis with pruritus. METHODS: We conducted this phase 2a, double-blind, randomised, placebo-controlled, crossover trial in two UK medical centres. Following 2 weeks of open placebo run-in, patients were randomly assigned in a 1:1 ratio with a block size of 4 to receive GSK2330672 or placebo twice daily during two consecutive 14-day treatment periods in a crossover sequence. The treatment periods were followed by a 14-day single-blinded placebo follow-up period. The primary endpoints were safety of GSK2330672, assessed using clinical and laboratory parameters, and tolerability as rated by the Gastrointestinal Symptom Rating Scale. The secondary endpoints were changes in pruritus scores measured using the 0 to 10 numerical rating scale (NRS), primary biliary cholangitis-40 (PBC-40) itch domain score and 5-D itch scale, changes in serum total bile acids and 7 alpha hydroxy-4-cholesten-3-one (C4), and changes in the pharmacokinetic parameters of ursodeoxycholic acid and its conjugates. The trial was registered with ClinicalTrials.gov, number NCT01899703. FINDINGS: Between March 10, 2014, and Oct 7, 2015, we enrolled 22 patients. 11 patients were assigned to receive intervention followed by placebo (sequence 1), and 11 patients were assigned to receive placebo followed by intervention (sequence 2). One patient assigned to sequence 2 withdrew consent prior to receiving randomised therapy. One patient did not attend the placebo follow-up period, but was included in the final analysis. GSK2330672 treatment for 14 days was safe with no serious adverse events reported. Diarrhoea was the most frequent adverse event during treatment with GSK2330672 (seven with GSK2330672 vs one with placebo) and headache was the most frequent adverse event during treatment with placebo (seven with placebo vs six with GSK2330672). After GSK2330672 treatment, the percentage changes from baseline itch scores were -57% (95% CI -73 to -42, p<0·0001) in the NRS, -31% (-42 to -20, p<0·0001) in the PBC-40 itch domain and -35% (-45 to -25, p<0·0001) in the 5-D itch scale. GSK2330672 produced significantly greater reduction from baseline than the double-blind placebo in the NRS (-23%, 95% CI -45 to -1; p=0·037), PBC-40 itch domain, (-14%, -26 to -1; p=0·034), and 5-D itch scale (-20%, -34 to -7; p=0·0045). After GSK2330672 treatment, serum total bile acid concentrations declined by 50% (95% CI -37 to -61, p<0·0001) from 30 to 15 µM, with a significant 3·1-times increase (95% CI 2·4 to 4·0, p<0·0001) in serum C4 concentrations from 7·9 to 24·7ng/mL. INTERPRETATION: In patients with primary biliary cholangitis with pruritus, 14 days of ileal bile acid transporter inhibition by GSK2330672 was generally well tolerated without serious adverse events, and demonstrated efficacy in reducing pruritus severity. GSK2330672 has the potential to be a significant and novel advance for the treatment of pruritus in primary biliary cholangitis. Diarrhoea, the most common adverse event associated with GSK2330672 treatment, might limit the long-term use of this drug. FUNDING: GlaxoSmithKline and National Institute for Health Research.

A randomized, double-blind, placebo-controlled trial of camicinal in Parkinson's disease.

BACKGROUND: Delayed gastric emptying may impair l-dopa absorption, contributing to motor fluctuations. We evaluated the effect of camicinal (GSK962040), a gastroprokinetic, on the absorption of l-dopa and symptoms of PD. METHODS: Phase II, double-blind, placebo-controlled trial. Participants were randomized to receive camicinal 50 mg once-daily (n = 38) or placebo (n = 20) for 7 to 9 days. RESULTS: l-dopa exposure was similar with coadministration of camicinal compared to placebo. Median time to maximum l-dopa concentration was reduced, indicating more rapid absorption of l-dopa. Camicinal resulted in significant reduction in OFF time (-2.31 hours; 95% confidence interval: -3.71, -0.90), significant increase in ON time (+1.88 hours; 95% confidence interval: 0.28, 3.48) per day, and significant decrease in mean total MDS-UPDRS score (-12.5; 95% confidence interval: -19.67, -5.29). Camicinal treatment was generally well tolerated. CONCLUSIONS: PD symptom improvement with camicinal occurred in parallel with more rapid absorption of l-dopa. This study provides evidence of an improvement of the motor response to l-dopa in people with PD treated with camicinal 50 mg once-daily compared with placebo, which will require further evaluation. © 2017 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

BAT117213: Ileal bile acid transporter (IBAT) inhibition as a treatment for pruritus in primary biliary cirrhosis: study protocol for a randomised controlled trial.

BACKGROUND: Pruritus (itch) is a symptom commonly experienced by patients with cholestatic liver diseases such as primary biliary cholangitis (PBC, previously referred to as primary biliary cirrhosis). Bile acids (BAs) have been proposed as potential pruritogens in PBC. The ileal bile acid transporter (IBAT) protein expressed in the distal ileum plays a key role in the enterohepatic circulation of BAs. Pharmacological inhibition of IBAT with GSK2330672 may reduce BA levels in the systemic circulation and improve pruritus. METHODS: This clinical study (BAT117213 study) is sponsored by GlaxoSmithKline (GSK) with associated exploratory studies supported by the National Institute for Health Research (NIHR). It is a phase 2a, multi-centre, randomised, double bind, placebo controlled, cross-over trial for PBC patients with pruritus. The primary objective is to investigate the safety and tolerability of repeat doses of GSK2330672, and explore whether GSK2330672 administration for 14 days improves pruritus compared with placebo. The key outcomes include improvement in pruritus scores evaluated on a numerical rating scale and other PBC symptoms in an electronic diary completed twice daily by the patients. The secondary outcomes include the evaluation of the effect of GSK2330672 on total serum bile acid (BA) concentrations, serum markers of BA synthesis and steady-state pharmacokinetics of ursodeoxycholic acid (UDCA). DISCUSSION: BAT117213 study is the first randomised controlled crossover trial of ileal bile acid transporter inhibitor, a novel class of drug to treat pruritus in PBC. The main strengths of the trial are utility of a novel, study specific, electronic symptom diary as patient reported outcome to measure the treatment response objectively and the crossover design that allows estimating the treatment effect in a smaller number of patients. The outcome of this trial will inform the trial design of future development phase of the IBAT inhibitor drug. The trial will also provide opportunity to conduct metabonomic and gut microbiome studies as explorative and mechanistic research in patients with cholestatic pruritus. TRIAL REGISTRATION: EudraCT number: 2012-005531-84, ClinicalTrials.gov Identifier: NCT01899703 , registered on 3(rd) July 2013.

The effect of camicinal (GSK962040), a motilin agonist, on gastric emptying and glucose absorption in feed-intolerant critically ill patients: a randomized, blinded, placebo-controlled, clinical trial.

BACKGROUND: The promotility agents currently available to treat gastroparesis and feed intolerance in the critically ill are limited by adverse effects. The aim of this study was to assess the pharmacodynamic effects and pharmacokinetics of single doses of the novel gastric promotility agent motilin agonist camicinal (GSK962040) in critically ill feed-intolerant patients. METHODS: A prospective, randomized, double-blind, parallel-group, placebo-controlled, study was performed in mechanically ventilated feed-intolerant patients [median age 55 (19-84), 73 % male, APACHE II score 18 (5-37) with a gastric residual volume ≥200 mL]. Gastric emptying and glucose absorption were measured both pre- and post-treatment after intragastric administration of 50 mg (n = 15) camicinal and placebo (n = 8) using the (13)C-octanoic acid breath test (BTt1/2), acetaminophen concentrations, and 3-O-methyl glucose concentrations respectively. RESULTS: Following 50 mg enteral camicinal, there was a trend to accelerated gastric emptying [adjusted geometric means: pre-treatment BTt1/2 117 minutes vs. post- treatment 76 minutes; 95 % confidence intervals (CI; 0.39, 1.08) and increased glucose absorption (AUC240min pre-treatment: 28.63 mmol.min/L vs. post-treatment: 71.63 mmol.min/L; 95 % CI (1.68, 3.72)]. When two patients who did not have detectable plasma concentrations of camicinal were excluded from analysis, camicinal accelerated gastric emptying (adjusted geometric means: pre-treatment BTt1/2 121 minutes vs. post-treatment 65 minutes 95 % CI (0.32, 0.91) and increased glucose absorption (AUC240min pre-treatment: 33.04 mmol.min/L vs. post-treatment: 74.59 mmol.min/L; 95 % CI (1.478, 3.449). In those patients receiving placebo gastric emptying was similar pre- and post-treatment. CONCLUSIONS: When absorbed, a single enteral dose of camicinal (50 mg) accelerates gastric emptying and increases glucose absorption in feed-intolerant critically ill patients. TRIAL REGISTRATION: The study protocol was registered with the US NIH clinicaltrials.gov on 23 December 2009 (Identifier NCT01039805 ).

Genetic variants in CDC42 and NXPH1 as susceptibility factors for constipation and diarrhoea predominant irritable bowel syndrome.

OBJECTIVE: The complex genetic aetiology underlying irritable bowel syndrome (IBS) needs to be assessed in large-scale genetic studies. Two independent IBS cohorts were genotyped to assess whether genetic variability in immune, neuronal and barrier integrity genes is associated with IBS. DESIGN: 384 single nucleotide polymorphisms (SNPs) covering 270 genes were genotyped in an exploratory cohort (935 IBS patients, 639 controls). 33 SNPs with Puncorrected<0.05 were validated in an independent set of 497 patients and 887 controls. Genotype distributions of single SNPs were assessed using an additive genetic model in IBS and clinical subtypes, IBS-C and IBS-D, both in individual and combined cohorts. Trait anxiety (N=614 patients, 533 controls), lifetime depression (N=654 patients, 533 controls) and mRNA expression in rectal biopsies (N=22 patients, 29 controls) were correlated with SNP genotypes. RESULTS: Two SNPs associated independently in the exploratory and validation cohort: rs17837965-CDC42 with IBS-C (ORexploratory=1.59 (1.05 to 1.76); ORvalidation=1.76 (1.03 to 3.01)) and rs2349775-NXPH1 with IBS-D (ORexploratory=1.28 (1.06 to 1.56); ORvalidation=1.42 (1.08 to 1.88)). When combining both cohorts, the association of rs2349775 withstood post hoc correction for multiple testing in the IBS-D subgroup. Additionally, three SNPs in immune-related genes (rs1464510-LPP, rs1881457-IL13, rs2104286-IL2RA), one SNP in a neuronal gene (rs2349775-NXPH1) and two SNPs in epithelial genes (rs245051-SLC26A2, rs17837965-CDC42) were weakly associated with total-IBS (Puncorrected<0.05). At the functional level, rs1881457 increased IL13 mRNA levels, whereas anxiety and depression scores did not correlate with rs2349775-NXPH1. CONCLUSIONS: Rs2349775 (NXPH1) and rs17837965 (CDC42) were associated with IBS-D and IBS-C, respectively, in two independent cohorts. Further studies are warranted to validate our findings and to determine the mechanisms underlying IBS pathophysiology.

Impaired emotional learning and involvement of the corticotropin-releasing factor signaling system in patients with irritable bowel syndrome.

BACKGROUND & AIMS: Alterations in central corticotropin-releasing factor signaling pathways have been implicated in the pathophysiology of anxiety disorders and irritable bowel syndrome (IBS). We aimed to characterize the effects of the corticotropin-releasing factor receptor 1 (CRF-R1) antagonist, GW876008, on brain and skin conductance responses during acquisition and extinction of conditioned fear to the threat of abdominal pain in subjects with IBS and healthy individuals (controls). METHODS: We performed a single-center, randomized, double-blind, 3-period crossover study of 11 women with IBS (35.50 ± 12.48 years old) and 15 healthy women (controls) given a single oral dose (20 mg or 200 mg) of the CRF-R1 antagonist or placebo. Blood-oxygen level-dependent responses were analyzed using functional magnetic resonance imaging in a tertiary care setting. RESULTS: Controls had greater skin conductance responses during acquisition than extinction, validating the fear-conditioning paradigm. In contrast, during extinction, women with IBS had greater skin conductance responses than controls-an effect normalized by administration of a CRF-R1 antagonist. Although the antagonist significantly reduced activity in the thalamus in patients with IBS and controls during acquisition, the drug produced greater suppression of blood-oxygen level-dependent activity in a wide range of brain regions in IBS patients during extinction, including the medial prefrontal cortex, pons, hippocampus, and anterior insula. CONCLUSIONS: Although CRF signaling via CRF-R1 is involved in fear acquisition and extinction learning related to expected abdominal pain in patients with IBS and controls, this system appears to be up-regulated in patients with IBS. This up-regulation might contribute to the previously reported abnormal brain responses to expected abdominal pain.

Identifying and testing candidate genetic polymorphisms in the irritable bowel syndrome (IBS): association with TNFSF15 and TNFα.

OBJECTIVES: The postinfectious irritable bowel syndrome (PI-IBS) suggests that impaired resolution of inflammation could cause IBS symptoms. The authors hypothesised that polymorphisms in genes whose expression were altered by gastroenteritis might be linked to IBS with diarrhoea (IBS-D) which closely resembles PI-IBS. DESIGN: Part 1: 25 healthy volunteers (HVs), 21 patients 6 months after Campylobacter jejuni infection, 37 IBS-D and 19 IBS with constipation (IBS-C) underwent rectal biopsy for gene expression analysis and peripheral blood mononuclear cell cytokine production assessment. Part 2: Polymorphisms in genes whose expression was altered in Part 1 were assessed in 179 HV, 179 IBS-D, 122 IBS-C and 41 PI-IBS. RESULTS: Part 1: Mucosal expression of seven genes was altered in IBS: CCL11, CCL13, Calpain 8 and TNFSF15 increased while NR1D1, GPR161 and GABRE decreased with similar patterns after infection with C jejuni. Part 2: The authors assessed 21 known single nucleotide polymorphisms (SNPs) in these seven genes and one SNP in each of the TNFα and IL-10 genes. Three out of five TNFSF15 SNPs (rs6478108, rs6478109 and rs7848647) showed reduced minor allele frequency (MAF) (0.28, 0.27 and 0.27) in subjects with IBS-D compared with HV (0.38, 0.36 and 0.37; p=0.007, 0.015 and 0.007, respectively) confirming others recent findings. The authors also replicated the previously reported association of the TNFα SNP rs1800629 with PI-IBS which showed an increase in the MAF at 0.30 versus 0.19 for HV (p=0.04). CONCLUSION: IBS-D and PI-IBS patients are associated with TNFSF15 and TNFα genetic polymorphisms which also predispose to Crohn's disease suggesting possible common underlying pathogenesis.

A randomized phase 2 study of the 5-HT4 receptor agonist felcisetrag for postoperative gastrointestinal dysfunction after bowel surgery.

BACKGROUND: Felcisetrag (5-hydroxytryptamine-4 receptor [5-HT4] agonist) is under investigation as prophylaxis or active treatment for accelerating resolution of gastrointestinal function post-surgery. METHODS: Phase 2, randomized, placebo-controlled, parallel five-arm, double-blind, multicenter study (NCT03827655) in 209 adults undergoing open or laparoscopic-assisted bowel surgery. Patients received intravenous placebo, felcisetrag 0.1 mg/100 â€‹mL or 0.5 mg/100 â€‹mL pre-surgery only, or pre-surgery and daily post-surgery until return of gastrointestinal function or for up to 10 days. PRIMARY ENDPOINT: time to recovery of gastrointestinal function. RESULTS: Median time to recovery of gastrointestinal function was 2.6 days for both felcisetrag 0.5 â€‹mg daily and 0.5 â€‹mg pre-surgery versus 1.9 days for placebo (p â€‹> â€‹0.05). There were no notable differences in adverse events between treatment arms. CONCLUSIONS: Felcisetrag was well tolerated with no new safety concerns. However, no clinically meaningful difference in time to recovery of gastrointestinal function versus placebo was observed. Further investigation of the utility of 5-HT4 agonists in complicated, open abdominal surgeries may be warranted.

Incidence and risk factors for postoperative gastrointestinal dysfunction occurrence after gastrointestinal procedures in US patients.

BACKGROUND: Incidence of, and potential risk factors for, postoperative gastrointestinal dysfunction (POGD) after gastrointestinal procedures performed in US hospitals were examined. METHODS: This retrospective study used hospital discharge data of inpatients who underwent ≥1 gastrointestinal procedures from 1-Jan-2016 to 30-Apr-2019. POGD incidence was calculated based on all hospitalizations for MDC-06 procedures. Predictors of POGD were assessed using multivariable logistic regression. RESULTS: POGD incidence was 5.8% among 638 611 inpatient hospitalizations. Major bowel procedures, peritoneal adhesiolysis, and appendectomy were the most notable predictors of POGD among gastrointestinal procedures assessed (adjusted odds ratios [95% confidence intervals]: 2.71 [2.59-2.83], 2.48 [2.34-2.64], and 2.15 [2.03-2.27], respectively; all p < 0.05). Procedures performed by colorectal/gastroenterology specialists (0.86 [0.84-0.89]), and those performed percutaneously (0.55 [0.54-0.56]) were associated with significantly lower odds of POGD (both P < 0.05). CONCLUSIONS: Findings may help clinicians tailor management plans targeting patients at high-risk of POGD.

Corticotropin-releasing factor receptor 1 antagonist alters regional activation and effective connectivity in an emotional-arousal circuit during expectation of abdominal pain.

Alterations in corticotropin-releasing factor (CRF) signaling pathways have been implicated in irritable bowel syndrome (IBS) pathophysiology. We aimed to (1) determine the effect of the selective CRF receptor 1 antagonist (CRF(1)) GW876008 relative to placebo, on regional activation and effective connectivity of a stress-related emotional-arousal circuit during expectation of abdominal pain using functional magnetic resonance imaging in human subjects with a diagnosis of IBS and healthy controls (HCs), and (2) examine GW876008 effects on state-trait anxiety and hypothalamic-pituitary-adrenal (HPA) axis response. Although there were no drug-related effects on peripheral HPA activity, significant central effects were observed in brain regions associated with the stress response. Effective connectivity analysis showed drug-induced normalizations between key regions of the emotional-arousal circuit in patients. During pain expectation, orally administered GW876008 relative to placebo produced significant blood oxygen level-dependent (BOLD) signal reductions in the amygdala, hippocampus, insula, anterior cingulate, and orbitomedial prefrontal cortices across groups. Patients showed significantly greater BOLD responses in the left locus coeruleus and hypothalamus after placebo compared with HCs, and BOLD signal decreases in the left hypothalamus after drug. The inhibitory effects of GW876008 in the hypothalamus in patients were moderated by anxiety; patients having average and high levels of state anxiety showed drug-related BOLD decreases. GW876008 represents a novel tool for elucidating the neuronal mechanisms and circuitry underlying hyperactivation of CRF/CRF(1) signaling and its role in IBS pathophysiology. The unique state anxiety effects observed suggest a potential pathway for therapeutic benefit of CRF(1) receptor antagonism for patients with stress-sensitive disorders.

The Effect of Hepatic Impairment on the Pharmacokinetics of Intravenously Administered Felcisetrag (TAK-954).

Felcisetrag (formerly known as TAK-954) is a selective serotonin receptor agonist under investigation for use in patients with postoperative gastrointestinal dysfunction. The safety, tolerability, and pharmacokinetics (PK) of intravenous (i.v.) felcisetrag have been studied, but little is known about the effect of hepatic impairment on the PK of the drug. This phase 1, non-randomized, open-label study compared the PK of a single 60-minute i.v. infusion of felcisetrag between healthy individuals (n = 8) and patients with moderate (n = 10) or severe (n = 7) hepatic impairment. The primary study end points were the total and free maximum observed plasma concentration of felcisetrag at the end of infusion (Cmax ), area under the concentration-time curve (AUC) from time 0 to the time of the last quantifiable concentration (AUClast ), and AUC from time 0 to infinity (AUCinf ). Concentration-time profiles of felcisetrag were similarly shaped between groups but revealed lower concentrations of total plasma felcisetrag with increasing severity of hepatic impairment, whereas concentrations of free felcisetrag increased. The ratios of AUClast and AUCinf for patients with severe hepatic impairment were up to 29.3% lower for total felcisetrag and up to 29.2% higher for free felcisetrag than found in healthy individuals (P < .05). Infusions were well tolerated with no discontinuations, severe adverse events, or deaths during the study. Overall, the effect of hepatic impairment on exposure to felcisetrag was minimal, suggesting that dose adjustment may be unnecessary in patients with hepatic impairment.

Evaluation of the pharmacokinetics of trazpiroben (TAK-906) in the presence and absence of the proton pump inhibitor esomeprazole.

Trazpiroben, a dopamine D2 /D3 receptor antagonist under development to treat gastroparesis, displays decreasing solubility with increasing pH. This single-sequence, open-label, two-period, crossover study evaluated the effect of esomeprazole, a proton pump inhibitor that raises gastric pH, on the single-dose pharmacokinetics, safety, and tolerability of trazpiroben in healthy adults (NCT03849690). In total, 12 participants were enrolled and entered period 1 (days 1-3), receiving a single oral dose of trazpiroben 25 mg on day 1. After a 4-day washout, participants then entered period 2 (days 8-13) and received esomeprazole 40 mg once daily on days 8-12, with a single oral dose of trazpiroben 25 mg co-administered 1 h post esomeprazole dosing on day 11. Geometric mean area under the curve from time 0 extrapolated to infinity (AUC∞ ) and maximum plasma concentration (Cmax ) values were generally similar when trazpiroben was administered alone versus alongside esomeprazole (AUC∞ , 44.03 vs. 38.85 ng h/ml; Cmax , 19.76 vs. 17.24 ng/ml). Additionally, the associated geometric mean ratio (GMR; co-administration: administration alone) 90% confidence intervals (CIs) suggested no clinically meaningful difference between treatment groups (AUC∞ , GMR 0.88, 90% CI 0.78-1.00; Cmax , 0.87, 90% CI 0.70-1.09). Mean apparent first-order terminal elimination half-life values were similar between treatments, illustrating co-administration with esomeprazole had minimal effect on trazpiroben elimination. Trazpiroben was well-tolerated in healthy adults following administration alone and alongside esomeprazole, with no clinically relevant adverse events reported. The lack of evidence of any clinically meaningful drug-drug interaction supports the co-administration of esomeprazole with trazpiroben.

The pharmacokinetics of oral trazpiroben (TAK-906) after organic anion transporting polypeptide 1B1/1B3 inhibition: A phase I, randomized study.

Trazpiroben is a dopamine D2 /D3 receptor antagonist under development for the treatment of gastroparesis. This phase I, open-label, randomized, two-way crossover study (NCT04121078) evaluated the effect of single-dose intravenous rifampin, a potent inhibitor of the organic anion transporting polypeptides (OATPs) 1B1 and 1B3, on the pharmacokinetics and safety of trazpiroben in healthy adults. The utility of coproporphyrin (CP) I and CPIII as biomarkers of OATP inhibition was also assessed. Overall, 12 participants were enrolled and randomized (1:1) into one of two treatment sequences (AB and BA). Participants received either a single oral dose of trazpiroben 25 mg (treatment A) or a single oral dose of trazpiroben 25 mg immediately after a single 30-min intravenous infusion of rifampin 600 mg (treatment B). After a washout period of at least 7 days, participants received the other treatment. Geometric mean area under the curve from time 0 extrapolated to infinity (AUC∞ ) and maximum serum concentration (Cmax ) of plasma trazpiroben were higher in participants receiving treatment B than those receiving treatment A (AUC∞ , 168.5 vs. 32.68 ng*h/ml; Cmax , 89.62 vs. 14.37 ng/ml); corresponding geometric mean ratios (90% confidence interval) showed 5.16 (4.25-6.25) and 6.24 (4.62-8.42)-fold increases in these parameters, respectively. In this study, trazpiroben was confirmed as a substrate of OATP1B1/1B3, and therefore co-administration of trazpiroben with moderate to strong inhibitors of OATP1B1/1B3 is not recommended. This is also the first assessment of the utility of CPI and CPIII as endogenous biomarkers of OATP1B1/1B3 inhibition after a single intravenous dose of rifampin.

Distinct neurophysiological profiles in irritable bowel syndrome.

The objective of this study was to determine whether cortical evoked potentials (CEPs) can define neurophysiological patterns in irritable bowel syndrome (IBS). In this prospective study of consecutive patients attending secondary and tertiary centers, patients with Rome II-defined IBS underwent rectal sensory and pain threshold (RST and RPT, respectively) testing with electrical stimulation on three separate visits. CEPs were collated for 75% pain thresholds, and anxiety [Spielberger State-Trait Anxiety Inventory (SSTAI)] questionnaires were completed. Subjects were 33 IBS patients (27 female, mean age 40.1 yr) and 21 healthy controls (14 female, mean age 31.4 yr). At visit 3, RPT was significantly lower [mean (95% CI)] in IBS patients than in control subjects: 58.2 mA (48.0-68.5) vs. 79.5 mA (69.3-89.6) (P < 0.01). No significant differences were observed in CEP latencies and amplitudes between visits 1, 2, and 3 within each group, except P2 latency for controls (P = 0.04) and N2 latency (P = 0.04) and N2 amplitude (P = 0.02) for IBS patients. Group comparisons showed significant differences in 3-day mean RPT, CEP amplitudes, and CEP latencies between IBS patients and controls. RPT <50 mA and P1 latency >106 ms were identified four IBS subgroups: 24% were hypersensitive, 12% were hypervigilant, 15% were hyposensitive, and 49% exhibited normal P1 latency and pain threshold. CEPs are reliable and reproducible measures of early sensory processing. Identification of four IBS neurophysiological patterns highlights its heterogeneous nature. These findings mark the first step toward personalized medicine in IBS, whereby therapy may be directed at the underlying physiological process.

A semi-mechanistic gastric emptying model for the population pharmacokinetic analysis of orally administered acetaminophen in critically ill patients.

PURPOSE: To develop a semi-mechanistic population pharmacokinetic model based on gastric emptying function for acetaminophen plasma concentration in critically ill patients tolerant and intolerant to enteral nutrition before and after prokinetic therapy. METHODS: Acetaminophen plasma concentrations were available from a study with 10 tolerant and 20 intolerant patients before and after prokinetic therapy with either erythromycin or metoclopramide. Population pharmacokinetic modelling was carried out in a nonlinear mixed effects analysis software, NONMEM. RESULTS: A four-compartment semi-mechanistic model for stomach, intestine, central and peripheral compartments was described. The rate of emptying of the stomach was described by a first-order rate parameter. The final model has two gastric emptying rate constant parameters: kg1 (1.30 h(-1), RSE=53.84%, T1/2=0.53 h) for the intolerant group before prokinetic therapy and kg2 (27.8 h(-1), RSE=59.35%, T1/2=0.025 h) for both the intolerant group after prokinetic therapy and the tolerant group. Other parameters and estimates (RSE) in the model were ka=5.12 h(-1) (28.13%), CL=13.0 L/h (19.62%), CLD=22.6 L/h (19.78%), V1=63.8 L (12.79%) and V2=69 L (38.70%). CONCLUSIONS: The four-compartment semi-mechanistic population pharmacokinetic model adequately described the data. The gastric emptying half-time is improved by a factor of about 20 in the patients that are intolerant to enteral nutrition after treatment with prokinetic agents.

Randomised clinical trial: safety, pharmacokinetics and pharmacodynamics of trazpiroben (TAK-906), a dopamine D2 /D3 receptor antagonist, in patients with gastroparesis.

BACKGROUND: Gastroparesis is a chronic gastric motility disorder. Dopamine D2 /D3 receptor antagonists metoclopramide and domperidone are current treatment options but are associated with central nervous system and cardiovascular safety concerns, respectively, precluding chronic use. Trazpiroben (TAK-906), a dopamine D2 /D3 receptor antagonist, is under development for chronic treatment of moderate-to-severe gastroparesis. Nonclinical data suggest trazpiroben will have D2 /D3 receptor antagonism comparable with metoclopramide or domperidone. AIMS: To evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics (effect on prolactin and gastric function) of twice-daily trazpiroben (5, 25 and 100 mg) in participants with gastroparesis. METHODS: This phase 2a pilot study evaluated gastric emptying using the gastric emptying breath test, with metoclopramide as an internal control. Gastric accommodation and gastroparesis symptoms were assessed using the nutrient drink test and American Neurogastroenterology and Motility Society Gastroparesis Cardinal Symptom Index-Daily Diary, respectively. RESULTS: Overall, 51 participants were enrolled. Trazpiroben was well tolerated, demonstrating a favourable safety profile without cardiovascular or central nervous system adverse events. All trazpiroben doses were rapidly absorbed and eliminated (t1/2z 4-5 hours), and D2 /D3 receptor target engagement confirmed by increased serum prolactin (peaking at trazpiroben 25 mg). No effect on gastric emptying was demonstrated with trazpiroben or metoclopramide (P > 0.05), although benefits in volume-to-fullness were seen at trazpiroben 5 mg (P > 0.05) and 25 mg (88.5 vs -26.3 mL; P = 0.019), and nonsignificant numerical aggregate symptom score improvements were observed with trazpiroben 25 mg vs placebo (P = 0.182). CONCLUSIONS: Trazpiroben was well tolerated with a favourable safety profile, supporting its further development for the treatment of gastroparesis. ClinicalTrials.gov identifier: NCT03268941.

Randomised study: effects of the 5-HT4 receptor agonist felcisetrag vs placebo on gut transit in patients with gastroparesis.

BACKGROUND: Gastroparesis is defined by delayed gastric emptying with associated symptoms in the absence of mechanical obstruction. AIM: To evaluate pharmacokinetics and pharmacodynamics of felcisetrag, a highly selective 5-HT4 receptor agonist, on total gut transit in patients with documented delayed gastric emptying of solids. METHODS: Single-centre, placebo-controlled study of 36 participants receiving placebo, 0.1mg, 0.3mg or 1.0mg of felcisetrag I.V. infusion, daily, for 3 days. At baseline, each participant completed a 4h, 99m Tc-egg meal (300 kcal, 30% fat) gastric emptying test. Following infusion (Day 2), gastric, small bowel and colonic transit of solids were measured over 48h (same meal plus 111 In-charcoal delivered in methacrylate-coated capsule). Samples were collected for pharmacokinetics. The primary endpoint was gastric emptying T1/2 . Statistical analysis used baseline parameters as covariates (ANCOVA). RESULTS: Patients (22 idiopathic, 14 diabetic gastroparesis) were randomised to felcisetrag (0.1 mg, n = 10; 0.3 mg, n = 9; 1.0 mg, n = 7) or placebo (n = 10). Compared to placebo, felcisetrag significantly accelerated gastric emptying T1/2 , colonic filling at 6h, and 10% small bowel transit time (overall P < 0.01; all three doses individually Bonferroni corrected P < 0.05) for all three measurements. Ascending colon emptying (T1/2 ) was significantly accelerated (all doses), and colonic transit at 48 hours was accelerated with 0.1 mg and 0.3 mg felcisetrag compared to placebo. Pharmacokinetic results were dose proportional. Felcisetrag was well tolerated with no clinically significant findings from clinical laboratory, vital signs or ECG. CONCLUSION: I.V. felcisetrag significantly accelerated gastric, small bowel and colonic transit in patients with gastroparesis, and should be further evaluated for short-term treatment of gastric and intestinal motility disorders. ClinicalTrials.gov #NCT03281577.

Neurophysiological evaluation of convergent afferents innervating the human esophagus and area of referred pain on the anterior chest wall.

Noxious stimuli in the esophagus cause pain that is referred to the anterior chest wall because of convergence of visceral and somatic afferents within the spinal cord. We sought to characterize the neurophysiological responses of these convergent spinal pain pathways in humans by studying 12 healthy subjects over three visits (V1, V2, and V3). Esophageal pain thresholds (Eso-PT) were assessed by electrical stimulation and anterior chest wall pain thresholds (ACW-PT) by use of a contact heat thermode. Esophageal evoked potentials (EEP) were recorded from the vertex following 200 electrical stimuli, and anterior chest wall evoked potentials (ACWEP) were recorded following 40 heat pulses. The fear of pain questionnaire (FPQ) was administered on V1. Statistical data are shown as point estimates of difference +/- 95% confidence interval. Pain thresholds increased between V1 and V3 [Eso-PT: V1-V3 = -17.9 mA (-27.9, -7.9) P < 0.001; ACW-PT: V1-V3 = -3.38 degrees C (-5.33, -1.42) P = 0.001]. The morphology of cortical responses from both sites was consistent and equivalent [P1, N1, P2, N2 complex, where P1 and P2 are is the first and second positive (downward) components of the CEP waveform, respectively, and N1 and N2 are the first and second negative (upward) components, respectively], indicating activation of similar cortical networks. For EEP, N1 and P2 latencies decreased between V1 and V3 [N1: V1-V3 = 13.7 (1.8, 25.4) P = 0.02; P2: V1-V3 = 32.5 (11.7, 53.2) P = 0.003], whereas amplitudes did not differ. For ACWEP, P2 latency increased between V1 and V3 [-35.9 (-60, -11.8) P = 0.005] and amplitudes decreased [P1-N1: V1-V3 = 5.4 (2.4, 8.4) P = 0.01; P2-N2: 6.8 (3.4, 10.3) P < 0.001]. The mean P1 latency of EEP over three visits was 126.6 ms and that of ACWEP was 101.6 ms, reflecting afferent transmission via Adelta fibers. There was a significant negative correlation between FPQ scores and Eso-PT on V1 (r = -0.57, P = 0.05). These data provide the first neurophysiological evidence of convergent esophageal and somatic pain pathways in humans.

Irritable bowel syndrome: more than abdominal pain and bowel habit abnormalities.

BACKGROUND & AIMS: Although irritable bowel syndrome (IBS) can be defined using few symptoms, principal symptoms alone may be inadequate in monitoring disorder severity. Secondary analysis of a published data set was performed to determine if more inclusive symptom measures would better reflect the burden of this disorder. METHODS: From a prospective naturalistic study of 213 patients meeting Rome II criteria, all the data were used from daily questionnaires recorded for 4 weeks, and repeated again after an interval of 4 weeks. The total number of 11 symptoms and intensity grading score of each symptom were analyzed alongside individual symptom intensities by principal component analysis. RESULTS: The trend accounting for the most variance was explained by the intensity of all symptoms together. The second largest trend was explained by differences between IBS bowel habits (constipation and diarrhea). The 2 constipation and 4 diarrhea symptoms closely correlated within each group, but the category of other symptoms were not correlated directly with either, and represent a separate dimension. Other symptoms (pain/discomfort, abdominal uneasiness, flatulence/distension, incomplete evacuation, pain or burning in the stomach) correlated more highly with disease intensity than either constipation or diarrhea symptoms. The sum of all symptoms and their intensity was consistent over each week, although the relative intensity of individual symptoms was more variable. Investigator measures of disease intensity underestimated that reported by patients. CONCLUSIONS: Non-bowel habit symptoms include more than abdominal pain and discomfort, and contribute to the largest component of the total symptom burden. Thus, more than bowel habits and abdominal pain drive IBS symptom severity.