Group-by-Treatment Interaction Effects in Comparative Bioavailability Studies.

Comparative bioavailability studies often involve multiple groups of subjects for a variety of reasons, such as clinical capacity limitations. This raises questions about the validity of pooling data from these groups in the statistical analysis and whether a group-by-treatment interaction should be evaluated. We investigated the presence or absence of group-by-treatment interactions through both simulation techniques and a meta-study of well-controlled trials. Our findings reveal that the test falsely detects an interaction when no true group-by-treatment interaction exists. Conversely, when a true group-by-treatment interaction does exist, it often goes undetected. In our meta-study, the detected group-by-treatment interactions were observed at approximately the level of the test and, thus, can be considered false positives. Testing for a group-by-treatment interaction is both misleading and uninformative. It often falsely identifies an interaction when none exists and fails to detect a real one. This occurs because the test is performed between subjects in crossover designs, and studies are powered to compare treatments within subjects. This work demonstrates a lack of utility for including a group-by-treatment interaction in the model when assessing single-site comparative bioavailability studies, and the clinical trial study structure is divided into groups.

Evaluation of the drug-drug interaction potential of treosulfan using a physiologically-based pharmacokinetic modelling approach.

AIMS: The aim of this work is the development of a mechanistic physiologically-based pharmacokinetic (PBPK) model using in vitro to in vivo extrapolation to conduct a drug-drug interaction (DDI) assessment of treosulfan against two cytochrome p450 (CYP) isoenzymes and P-glycoprotein (P-gp) substrates. METHODS: A PBPK model for treosulfan was developed de novo based on literature and unpublished clinical data. The PBPK DDI analysis was conducted using the U.S. Food and Drug Administration (FDA) DDI index drugs (probe substrates) midazolam, omeprazole and digoxin for CYP3A4, CYP2C19 and P-gp, respectively. Qualified and documented PBPK models of the probe substrates have been adopted from an open-source online model database. RESULTS: The PBPK model for treosulfan, based on both in vitro and in vivo data, was able to predict the plasma concentration-time profiles and exposure levels of treosulfan applied for a standard conditioning treatment. Medium and low potentials for DDI on CYP3A4 (maximum area under the concentration-time curve ratio (AUCRmax = 2.23) and CYP2C19 (AUCRmax = 1.6) were predicted, respectively, using probe substrates midazolam and omeprazole. Treosulfan was not predicted to cause a DDI on P-gp. CONCLUSION: Medicinal products with a narrow therapeutic index (eg, digoxin) that are substrates for CYP3A4, CYP2C19 or P-gp should not be given during treatment with treosulfan. However, considering the comprehensive treosulfan-based conditioning treatment schedule and the respective pharmacokinetic properties of the concomitantly used drugs (eg, half-life), the potential for interaction on all evaluated mechanisms would be low (AUCR < 1.25), if concomitantly administered drugs are dosed either 2 hours before or 8 hours after the 2-hour intravenous infusion of treosulfan.

Assessing consistency in clinical trials with two subgroups and binary endpoints: A new test within the logistic regression model.

In late stage drug development, the experimental drug is tested in a diverse study population within the relevant indication. In order to receive marketing authorization, robust evidence for the therapeutic efficacy is crucial requiring investigation of treatment effects in well-defined subgroups. Conventionally, consistency analyses in subgroups have been performed by means of interaction tests. However, the interaction test can only reject the null hypothesis of equivalence and not confirm consistency. Simulation studies suggest that the interaction test has low power but can also be oversensitive depending on sample size-leading in combination with the actually ill-posed null hypothesis to findings regardless of clinical relevance. In order to overcome these disadvantages in the setup of binary endpoints, we propose to use a consistency test based on the interval inclusion principle, which is able to reject heterogeneity and confirm consistency of subgroup-specific treatment effects while controlling the type I error. This homogeneity test is based upon the deviation between overall treatment effect and subgroup-specific effects on the odds ratio scale and is compared with an equivalence test based on the ratio of both subgroup-specific effects. Performance of these consistency tests is assessed in a simulation study. In addition, the consistency tests are outlined for the relative risk regression. The proposed homogeneity test reaches sufficient power in realistic scenarios with small interactions. As expected, power decreases for unbalanced subgroups, lower sample sizes, and narrower margins. Severe interactions are covered by the null hypothesis and are more likely to be rejected the stronger they are.

The potential of the estimands framework for clinical pharmacology trials: Some discussion points.

The recently finalised and published guideline ICH E9 (R1) introduced a new framework for the statistical analysis of clinical trials, namely that of "estimands". While the framework was originally developed for the analysis of late-phase trials, it could also provide a rigorous basis for the analysis of clinical pharmacology trials. We illustrate potential applications on two examples: a multiple dose pharmacology trial and the interpretation of confirmatory bioequivalence (BE) trials according to the current FDA and EMA BE guidelines.

Statistical reporting of clinical pharmacology research.

Research in clinical pharmacology covers a wide range of experiments, trials and investigations: clinical trials, systematic reviews and meta-analyses of drug usage after market approval, the investigation of pharmacokinetic-pharmacodynamic relationships, the search for mechanisms of action or for potential signals for efficacy and safety using biomarkers. Often these investigations are exploratory in nature, which has implications for the way the data should be analysed and presented. Here we summarize some of the statistical issues that are of particular importance in clinical pharmacology research.

[Chemotherapy in the Elderly with Non-Small Cell Lung Cancer: A Non-Interventional, Prospective, Multicentric Observational Study]. / Chemotherapie beim älteren Patienten mit nicht kleinzelligem Lungenkarzinom: Eine nicht-interventionelle, prospektive, multizentrische Beobachtungsstudie.

Background Elderly patients (70 years or older) with non-small cell lung cancer (NSCLC) do benefit from systemic chemotherapy as shown in many studies. We prospectively collected multicentric data on therapeutic decisions from patients 70 years or older to reflect the reality in the German health care system. Material and Methods Patients 70 years or older with NSCLC Stage IIIB or IV were eligible. No more than 20 consecutive patients from each center were included. Comorbidities, weighted by the Charlson-comorbidity-index, and survival data were collected. Results 253 patients were documented. Median age was 75.5 years (range 70 to 92) and 75 % were male. 2 % had no comorbidities, 5 % one, 15 % two, 24 % three and 55 % more than three. 237 patients (94 %) received systemic chemotherapy: 172 (73 %) as a combination and 58 (24 %) as monotherapy. Data from seven patients regarding therapy are missing. Combination regimens were in 66 % carboplatin- and in 30 % cisplatin-based. The most frequently given monotherapy was vinorelbin in 50 % of cases. In the group of the patients older than 80 years (n = 38), 53 % received mono therapy, 29 % a carboplatin-based regimen and 16 % no chemotherapy. Cisplatin was not administered in this age group. Median overall survival (OS) was 16.9 months. Patients with a Charlson-score ≤ 6 had 17.9 months, those > 6 12.0 months. With combination chemotherapy median OS was 23.5 months. Patients > 80 years had a median OS of 5.7 months. Conclusion A high percentage of patients older than 70 years received systemic therapy. Survival depended more on comorbidities than on age.

A Phase I study to determine the pharmacokinetic profile, safety and tolerability of sildenafil (Revatio® ) in cardiac surgery: the REVAKI-1 study.

AIMS: Acute kidney injury (AKI) is a common and severe complication of cardiac surgery. There is no effective prevention or treatment. Sildenafil citrate (Revatio® , Pfizer Inc.), a phosphodiesterase type 5 inhibitor, prevents post cardiac surgery AKI in pre-clinical studies, however its use is contraindicated in patients with symptomatic cardiovascular disease. The aim of this study is to assess the safety and pharmacokinetics of intravenous sildenafil in cardiac surgery patients. METHODS: We conducted an open label, dose escalation study with six patients per dose level. The six doses were 2.5 mg, 5 mg or 10 mg as a bolus, either alone or followed by an additional 2 h infusion of 2.5 mg sildenafil. RESULTS: Thirty-six patients entered the trial, of which 33 completed it. The mean age was 69.9 years. One patient died during surgery, two others were removed from the trial before dosing (all at dose level 5 mg + 2.5 mg). The pharmacokinetic profile of sildenafil was similar to previously published studies. For a dose of 10 mg administered as a bolus followed by 2.5 mg administered over 2 h the results were AUC∞ 537 ng h ml-1 , Cmax 189.4 ng ml-1 and t1/2 10.5 h. The drug was well tolerated with no serious adverse events related to drug administration. Higher sildenafil doses stabilized post-surgery nitric oxide bioavailability. CONCLUSIONS: Pharmacokinetics of sildenafil during cardiopulmonary bypass were comparable to those of other patient groups. The drug was well tolerated at therapeutic plasma levels. These results support the further evaluation of sildenafil for the prevention of AKI in cardiac surgery.

Infarct size following complete revascularization in patients presenting with STEMI: a comparison of immediate and staged in-hospital non-infarct related artery PCI subgroups in the CvLPRIT study.

BACKGROUND: The CvLPRIT study showed a trend for improved clinical outcomes in the complete revascularisation (CR) group in those treated with an immediate, as opposed to staged in-hospital approach in patients with multivessel coronary disease undergoing primary percutaneous intervention (PPCI). We aimed to assess infarct size and left ventricular function in patients undergoing immediate compared with staged CR for multivessel disease at PPCI. METHODS: The Cardiovascular Magnetic Resonance (CMR) substudy of CvLPRIT was a multicentre, prospective, randomized, open label, blinded endpoint trial in PPCI patients with multivessel disease. These data refer to a post-hoc analysis in 93 patients randomized to the CR arm (63 immediate, 30 staged) who completed a pre-discharge CMR scan (median 2 and 4 days respectively) after PPCI. The decision to stage non-IRA revascularization was at the discretion of the treating interventional cardiologist. RESULTS: Patients treated with a staged approach had more visible thrombus (26/30 vs. 31/62, p = 0.001), higher SYNTAX score in the IRA (9.5, 8-16 vs. 8.0, 5.5-11, p = 0.04) and a greater incidence of no-reflow (23.3 % vs. 1.6 % p < 0.001) than those treated with immediate CR. After adjustment for confounders, staged patients had larger infarct size (19.7 % [11.7-37.6] vs. 11.6 % [6.8-18.2] of LV Mass, p = 0.012) and lower ejection fraction (42.2 ± 10 % vs. 47.4 ± 9 %, p = 0.019) compared with immediate CR. CONCLUSIONS: Of patients randomized to CR in the CMR substudy of CvLPRIT, those in whom the operator chose to stage revascularization had larger infarct size and lower ejection fraction, which persisted after adjusting for important covariates than those who underwent immediate CR. Prospective randomized trials are needed to assess whether immediate CR results in better clinical outcomes than staged CR. TRIAL REGISTRATION: ISRCTN70913605 , Registered 24th February 2011.

Cluster randomised trial of a tailored intervention to improve the management of overweight and obesity in primary care in England.

BACKGROUND: Tailoring is a frequent component of approaches for implementing clinical practice guidelines, although evidence on how to maximise the effectiveness of tailoring is limited. In England, overweight and obesity are common, and national guidelines have been produced by the National Institute for Health and Care Excellence. However, the guidelines are not routinely followed in primary care. METHODS: A tailored implementation intervention was developed following an analysis of the determinants of practice influencing the implementation of the guidelines on obesity and the selection of strategies to address the determinants. General practices in the East Midlands of England were invited to take part in a cluster randomised controlled trial of the intervention. The primary outcome measure was the proportion of overweight or obese patients offered a weight loss intervention. Secondary outcomes were the proportions of patients with (1) a BMI or waist circumference recorded, (2) record of lifestyle assessment, (3) referred to weight loss services, and (4) any change in weight during the study period. We also assessed the mean weight change over the study period. Follow-up was for 9 months after the intervention. A process evaluation was undertaken, involving interviews of samples of participating health professionals. RESULTS: There were 16 general practices in the control group, and 12 in the intervention group. At follow-up, 15.08 % in the control group and 13.19 % in the intervention group had been offered a weight loss intervention, odds ratio (OR) 1.16, 95 % confidence interval (CI) (0.72, 1.89). BMI/waist circumference measurement 42.71 % control, 39.56 % intervention, OR 1.15 (CI 0.89, 1.48), referral to weight loss services 5.10 % control, 3.67 % intervention, OR 1.45 (CI 0.81, 2.63), weight management in the practice 9.59 % control, 8.73 % intervention, OR 1.09 (CI 0.55, 2.15), lifestyle assessment 23.05 % control, 23.86 % intervention, OR 0.98 (CI 0.76, 1.26), weight loss of at least 1 kg 42.22 % control, 41.65 % intervention, OR 0.98 (CI 0.87, 1.09). Health professionals reported the interventions as increasing their confidence in managing obesity and providing them with practical resources. CONCLUSIONS: The tailored intervention did not improve the implementation of the guidelines on obesity, despite systematic approaches to the identification of the determinants of practice. The methods of tailoring require further development to ensure that interventions target those determinants that most influence implementation. TRIAL REGISTRATION: ISRCTN07457585.

Complete Versus Lesion-Only Primary PCI: The Randomized Cardiovascular MR CvLPRIT Substudy.

BACKGROUND: Complete revascularization may improve outcomes compared with an infarct-related artery (IRA)-only strategy in patients being treated with primary percutaneous coronary intervention (PPCI) who have multivessel disease presenting with ST-segment elevation myocardial infarction (STEMI). However, there is concern that non-IRA PCI may cause additional non-IRA myocardial infarction (MI). OBJECTIVES: This study sought to determine whether in-hospital complete revascularization was associated with increased total infarct size compared with an IRA-only strategy. METHODS: This multicenter prospective, randomized, open-label, blinded endpoint clinical trial evaluated STEMI patients with multivessel disease having PPCI within 12 h of symptom onset. Patients were randomized to either IRA-only PCI or complete in-hospital revascularization. Contrast-enhanced cardiovascular magnetic resonance (CMR) was performed following PPCI (median day 3) and stress CMR at 9 months. The pre-specified primary endpoint was infarct size on pre-discharge CMR. The study had 80% power to detect a 4% difference in infarct size with 100 patients per group. RESULTS: Of the 296 patients in the main trial, 205 participated in the CMR substudy, and 203 patients (98 complete revascularization and 105 IRA-only) completed the pre-discharge CMR. The groups were well-matched. Total infarct size (median, interquartile range) was similar to IRA-only revascularization: 13.5% (6.2% to 21.9%) versus complete revascularization, 12.6% (7.2% to 22.6%) of left ventricular mass, p = 0.57 (95% confidence interval for difference in geometric means 0.82 to 1.41). The complete revascularization group had an increase in non-IRA MI on the pre-discharge CMR (22 of 98 vs. 11 of 105, p = 0.02). There was no difference in total infarct size or ischemic burden between treatment groups at follow-up CMR. CONCLUSIONS: Multivessel PCI in the setting of STEMI leads to a small increase in CMR-detected non-IRA MI, but total infarct size was not significantly different from an IRA-only revascularization strategy. (Complete Versus Lesion-Only Primary PCI Pilot Study [CvLPRIT]; ISRCTN70913605).

A randomised controlled trial of six weeks of home enteral nutrition versus standard care after oesophagectomy or total gastrectomy for cancer: report on a pilot and feasibility study.

BACKGROUND: Poor nutrition in the first months after oesophago-gastric resection is a contributing factor to the reduced quality of life seen in these patients. The aim of this pilot and feasibility study was to ascertain the feasibility of conducting a multi-centre randomised controlled trial to evaluate routine home enteral nutrition in these patients. METHODS: Patients undergoing oesophagectomy or total gastrectomy were randomised to either six weeks of home feeding through a jejunostomy (intervention), or treatment as usual (control). Intervention comprised overnight feeding, providing 50 % of energy and protein requirements, in addition to usual oral intake. Primary outcome measures were recruitment and retention rates at six weeks and six months. Nutritional intake, nutritional parameters, quality of life and healthcare costs were also collected. Interviews were conducted with a sample of participants, to ascertain patient and carer experiences. RESULTS: Fifty-four of 112 (48 %) eligible patients participated in the study over the 20 months. Study retention at six weeks was 41/54 patients (76 %) and at six months was 36/54 (67 %). At six weeks, participants in the control group had lost on average 3.9 kg more than participants in the intervention group (95 % confidence interval [CI] 1.6 to 6.2). These differences remained evident at three months (mean difference 2.5 kg, 95 % CI -0.5 to 5.6) and at six months (mean difference 2.5 kg, 95 % CI -1.2 to 6.1). The mean values observed in the intervention group for mid arm circumference, mid arm muscle circumference, triceps skin fold thickness and right hand grip strength were greater than for the control group at all post hospital discharge time points. The economic evaluation suggested that it was feasible to collect resource use and EQ-5D data for a full cost-effectiveness analysis. Thematic analysis of 15 interviews identified three main themes related to the intervention and the trial: 1) a positive experience, 2) the reasons for taking part, and 3) uncertainty of the study process. CONCLUSIONS: This study demonstrated that home enteral feeding by jejunostomy was feasible, safe and acceptable to patients and their carers. Whether home enteral feeding as 'usual practice' is a cost-effective therapy would require confirmation in an appropriately powered, multi-centre study. TRIAL REGISTRATION: UK Clinical Research Network ID 12447 (main trial, first registered 30 May 2012); UK Clinical Research Network ID 13361 (qualitative substudy, first registered 30 May 2012); ClinicalTrials.gov NCT01870817 (first registered 28 May 2013).

Linagliptin fixed-dose combination with metformin is bioequivalent to co-administration of linagliptin and metformin as individual tablets.

OBJECTIVE: To demonstrate bioequivalence of linagliptin/metformin fixed-dose combination (FDC) tablets and the corresponding combination of individual tablets taken together, i.e., free-pill (FP) treatment. METHODS: Three dosing combinations were evaluated in three separate randomized studies: linagliptin 2.5 mg with 500 mg, 850 mg, or 1,000 mg metformin. These studies used a prospective, open-label, randomized, two-way crossover design to evaluate bioequivalence in healthy volunteers (n = 287). After an overnight fast, participants received an FDC tablet once, and on a separate visit received the corresponding FP treatment. The two possible treatment sequences (FDC/FP and FP/FDC) were randomly allocated to the participants. A washout period of 35 days separated the two study treatments. The primary endpoints were maximum plasma concentration (Cmax) of linagliptin and metformin, area under the plasma concentration time curve from 0 to 72 hours (AUC0-72) for linagliptin, and from 0 to infinity (AUC0-inf) for metformin. RESULTS: The 90% confidence intervals of the adjusted geometric mean ratios of Cmax and AUC (calculated as FDC/ FP) were within the bioequivalence acceptance limits of 80 - 125%. The number of participants reporting at least one adverse event following FDC treatments was comparable to, or less than, that following FP treatments. Evaluation of vital signs and clinical laboratory tests revealed no safety issues. CONCLUSIONS: FDC tablets of linagliptin and metformin are bioequivalent to individual tablets of respective dose strengths taken together. Both treatments were well tolerated.

Effect of food and tablet-dissolution characteristics on the bioavailability of linagliptin fixed-dose combination with metformin: evidence from two randomized trials.

OBJECTIVE: The objectives of the studies reported here were to determine the relative bioavailability of linagliptin and metformin when administered in a fixed-dose combination (FDC) tablet with and without food, and to investigate the relative bioavailability of linagliptin and metformin FDC tablets from two treatment batches with different dissolution behavior. METHODS: These studies were open-label, single-dose, randomized, two-way crossover trials. After an overnight fast, healthy volunteers received an FDC tablet once (with/without food in the food-effect study; or from one of two batches with differing dissolution behavior in the tablet-dissolution study). On a separate visit, following a washout period of 35 days, participants received the alternative treatment. In the food-effect study the primary endpoints were maximum measured concentration in plasma (C(max)) for linagliptin and metformin, area under the plasma concentration-time curve from 0 to 72 hours (AUC(0-72)) for linagliptin and from 0 to infinity (AUC(0-inf)) for metformin. In the tablet-dissolution study the primary endpoints were Cmax for both analytes, AUC(0-72) for linagliptin, and from 0 to the time of the last quantifiable data point (AUC(0-t)) for metformin. RESULTS: The administration of the FDC tablet with food had no influence on the relative bioavailability of linagliptin and metformin with regard to the extent of exposure as determined by AUC(0-72) (linagliptin) and AUC(0-inf) (metformin) compared with FDC tablet administration while fasting. After food intake, peak plasma concentrations of linagliptin were slightly lowered (from 4.99 to 4.56 nmol L⁻¹), but the 90% confidence interval (CI) of the geometric mean test/reference ratio was still located within the generally applied bioequivalence acceptance limits of 80 - 125%. The median time from dosing to the maximum concentration of linagliptin in plasma (t(max)) was similar under both conditions. Administration with food reduced the rate of absorption of metformin indicated by a prolongation in median tmax (from 2 to 4 hours) and a decrease in Cmax by ~ 18%. There were no notable differences between the two treatment groups with respect to safety and tolerability. In the tablet-dissolution study, bioequivalence was demonstrated between linagliptin/metformin FDC tablets with normal and slower dissolution characteristics. For both linagliptin and metformin, the 90% CI of all pharmacokinetic (PK) parameters were well within the bioequivalence acceptance limits of 80 - 125%. Tablets from both batches were well tolerated with no unexpected adverse events. CONCLUSIONS: Food did not have a relevant impact on the bioavailability of linagliptin from the FDC tablet. The effect of food on the metformin component was comparable to that previously demonstrated. Furthermore, differences in tablet-dissolution characteristics did not have an impact on the bioavailability of linagliptin or metformin from the FDC tablet.

Evaluation of a tailored intervention to improve management of overweight and obesity in primary care: study protocol of a cluster randomised controlled trial.

BACKGROUND: In the UK around 22% of men and 24% of women are obese, and there are varying but worrying levels in other European countries. Obesity is a chronic condition that carries an important health risk. National guidelines, for use in England, on the management of people who are overweight or obese have been published by the National Institute for Health and Clinical Excellence (NICE, 2006). NICE recommendations for primary care teams are: determine the degree of overweight and obesity; assess lifestyle, comorbidities and willingness to change; offer multicomponent management of overweight and obesity; referral to external services when appropriate. This study investigates a tailored intervention to improve the implementation of these recommendations by primary care teams. METHODS/DESIGN: The study is a cluster randomised controlled trial. Primary care teams will be recruited from the East Midlands of England, and randomised into two study arms: 1) the study group, in which primary care teams are offered a set of tailored interventions to help implement the NICE guidelines for overweight and obesity; or 2) the control group in which primary care teams continue to practice usual care. The primary outcome is the proportion of overweight or obese patients for whom the primary care team adheres to the NICE guidelines. Secondary outcomes include the proportion of patients with a record of lifestyle assessment, referral to external weight loss services, the proportion of obese patients who lose weight during the intervention period, and the mean weight change over the same period. DISCUSSION: Although often recommended, the methods of tailoring implementation interventions to account for the determinants of practice are not well developed. This study is part of a programme of studies seeking to develop the methods of tailored implementation. TRIAL REGISTRATION: Current Controlled Trials ISRCTN07457585. Registered 09/08/2013. Randomisation commenced 30/08/2013.

Rationale, design, and organization of a randomized, controlled Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS) in patients with type 2 diabetes and established cardiovascular disease.

Sitagliptin, an oral dipeptidyl peptidase-4 inhibitor, lowers blood glucose when administered as monotherapy or in combination with other antihyperglycemic agents. TECOS will evaluate the effects of adding sitagliptin to usual diabetes care on cardiovascular outcomes and clinical safety. TECOS is a pragmatic, academically run, multinational, randomized, double-blind, placebo-controlled, event-driven trial recruiting approximately 14,000 patients in 38 countries who have type 2 diabetes (T2DM), are at least 50 years old, have cardiovascular disease, and have an hemoglobin A1c value between 6.5% and 8.0%. Eligible participants will be receiving stable mono- or dual therapy with metformin, sulfonylurea, or pioglitazone, or insulin alone or in combination with metformin. Randomization is 1:1 to double-blind sitagliptin or matching placebo, in addition to existing therapy in a usual care setting. Follow-up occurs at 4-month intervals in year 1 and then twice yearly until 1300 confirmed primary end points have occurred. Glycemic equipoise between randomized groups is a desired aim. The primary composite cardiovascular endpoint is time to the first occurrence of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for unstable angina, with cardiovascular events adjudicated by an independent committee blinded to study therapy. TECOS is a pragmatic-design cardiovascular outcome trial assessing the cardiovascular effects of sitagliptin when added to usual T2DM management.

The sodium glucose cotransporter 2 inhibitor empagliflozin does not prolong QT interval in a thorough QT (TQT) study.

BACKGROUND: Empagliflozin is a potent, selective sodium glucose cotransporter 2 (SGLT2) inhibitor in development as an oral antidiabetic treatment. This QT interval study assessed potential effects of empagliflozin on ventricular repolarisation and other electrocardiogram (ECG) parameters. METHODS: A randomised, placebo-controlled, single-dose, double-blind, five-period crossover study incorporating a novel double-placebo period design to reduce sample size, while maintaining full statistical power. TREATMENTS: single empagliflozin doses of 25 mg (therapeutic) and 200 mg (supratherapeutic), matching placebo and open-label moxifloxacin 400 mg (positive control). Triplicate 12-lead ECGs of 10 second duration were recorded at baseline and during the first 24 hours after dosing. The primary endpoint was mean change from baseline (MCfB) in the population heart rate-corrected QT interval (QTcN) between 1-4 hours after dosing. RESULTS: Thirty volunteers (16 male, 14 female, mean [range] age: 34.5 [18-52] years) were randomised. The placebo-corrected MCfB in QTcN 1-4 hours after dosing was 0.6 (90% CI: -0.7, 1.9) ms and -0.2 (-1.4, 0.9) ms for empagliflozin 25 mg and 200 mg, respectively, below the ICH E14 defined threshold of regulatory concern 10 ms. Assay sensitivity was confirmed by a placebo-corrected MCfB in QTcN 2-4 hours post-dose of 12.4 (10.7, 14.1) ms with moxifloxacin 400 mg. Empagliflozin tolerability was good for all volunteers; 23.3% experienced adverse events (AEs) with empagliflozin and 27.6% with placebo. The most frequent AE was nasopharyngitis. CONCLUSIONS/INTERPRETATION: Single doses of empagliflozin 25 mg and 200 mg were not associated with QTcN prolongation and were well tolerated in healthy volunteers. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01195675.

Dabigatran does not prolong the QT interval with supratherapeutic exposure: a thorough QT study in healthy subjects.

BACKGROUND: Dabigatran etexilate is a pro-drug of the oral reversible direct thrombin inhibitor dabigatran that interacts with the active site in the catalytic domain of the thrombin molecule. OBJECTIVE: To assess the electrophysiological effects of therapeutic and supratherapeutic doses of dabigatran etexilate in healthy subjects, a thorough QT study was performed. METHODS: In this single-centre, blinded, placebo- and active-controlled, four-period, crossover study, 40 healthy Caucasian subjects (20 women and 20 men) received single oral doses of dabigatran etexilate (150 mg and 600 mg), moxifloxacin 400 mg (positive control) or placebo, in a randomized order. Electrocardiogram (ECG) profiles were recorded at baseline and during the randomized study treatment in each period. The individually heart-rate-corrected QT interval (QTcI) was the primary parameter. The primary endpoint was the mean of these QTcI values obtained at 1.5, 2 and 3 h following study drug administration minus the mean of the time-matched QTcI values obtained at baseline day -1. The hypothesis tested was that the difference between each of the two doses of dabigatran etexilate (150 mg and 600 mg) and placebo, for the mean time-matched change from baseline (CfB) of QTcI between 1.5 and 3 h (the primary endpoint), was greater than or equal to 10 ms. Secondary endpoints were the time-matched CfB of QTcI between 0.5 and 24 h post-dose. RESULTS: All subjects completed the study without premature discontinuation and all treatments were well tolerated. Following dabigatran etexilate administration, the mean values of the placebo-adjusted time-matched CfB of QTcI between 1.5 and 3 h post-dose were close to 0; the upper bound of the two-sided 90 % confidence interval (CI) was 1.4 ms for dabigatran etexilate 150 mg and 1.3 ms for dabigatran etexilate 600 mg. The placebo-adjusted time-matched CfB of QTcI remained close to 0 at all time points, and all 90 % CIs were between -5 ms and 5 ms, well below the pre-defined non-inferiority margin of 10 ms. CONCLUSION: This thorough QT study demonstrated that therapeutic and fourfold supratherapeutic doses of dabigatran etexilate do not prolong QT intervals.

Evaluation of a self-administered oral glucose tolerance test.

OBJECTIVE: To assess the feasibility of using a disposable, self-administered, capillary blood sampling oral glucose tolerance test (OGTT) device in a community setting. RESEARCH DESIGN AND METHODS: Eighteen healthy and 12 type 2 diabetic volunteers underwent six 75-g OGTTs using a prototype device in the following three settings: unaided at home (twice); unaided but observed in clinic (twice); and performed by a nurse with simultaneous laboratory glucose assays of 0- and 120-min venous plasma samples (twice). The device displayed no results. A detachable data recorder returned to the clinic provided plasma-equivalent 0- and 120-min glucose values and key parameters, including test date, start and end times, and time taken to consume the glucose drink. RESULTS: The device was universally popular with participants and was perceived as easy to use, and the ability to test at home was well liked. Device failures meant that 0- and 120-min glucose values were obtained for only 141 (78%) of the 180 OGTTs performed, independent of setting. Device glucose measurements showed a mean bias compared with laboratory-measured values of +0.9 at 5.0 mmol/L increasing to +4.4 at 15.0 mmol/L. Paired device glucose values were equally reproducible across settings, with repeat testing showing no training effect regardless of setting order. CONCLUSIONS: Self-administered OGTTs can be performed successfully by untrained individuals in a community setting. With improved device reliability and appropriate calibration, this novel technology could be used in routine practice to screen people who might need a formal OGTT to confirm the presence of impaired glucose tolerance or diabetes.