Bret Musser

Safety and tolerability of sitagliptin in clinical studies: a pooled analysis of data from 10,246 patients with type 2 diabetes.

BackgroundIn a previous pooled analysis of 12 double-blind clinical studies that included data on 6,139 patients with type 2 diabetes, treatment with sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, was shown to be generally well tolerated compared with treatment with control agents. As clinical development of sitagliptin continues, additional studies have been completed, and more patients have been exposed to sitagliptin. The purpose of the present analysis is to update the safety and tolerability assessment of sitagliptin by pooling data from 19 double-blind clinical studies.MethodsThe present analysis included data from 10,246 patients with type 2 diabetes who received either sitagliptin 100 mg/day (N = 5,429; sitagliptin group) or a comparator agent (placebo or an active comparator) (N = 4,817; non-exposed group). The 19 studies from which this pooled population was drawn represent the double-blind, randomized studies that included patients treated with the usual clinical dose of sitagliptin (100 mg/day) for between 12 weeks and 2 years and for which results were available as of July 2009. These 19 studies assessed sitagliptin taken as monotherapy, initial combination therapy with metformin or pioglitazone, or as add-on combination therapy with other antihyperglycemic agents (metformin, pioglitazone, a sulfonylurea ± metformin, insulin ± metformin, or rosiglitazone + metformin). Patients in the non-exposed group were taking placebo, metformin, pioglitazone, a sulfonylurea ± metformin, insulin ± metformin, or rosiglitazone + metformin. The analysis used patient-level data from each study to evaluate between-group differences in the exposure-adjusted incidence rates of adverse events.ResultsSummary measures of overall adverse events were similar in the sitagliptin and non-exposed groups, except for an increased incidence of drug-related adverse events in the non-exposed group. Incidence rates of specific adverse events were also generally similar between the two groups, except for increased incidence rates of hypoglycemia, related to the greater use of a sulfonylurea, and diarrhea, related to the greater use of metformin, in the non-exposed group and constipation in the sitagliptin group. Treatment with sitagliptin was not associated with an increased risk of major adverse cardiovascular events.ConclusionsIn this updated pooled safety analysis of data from 10,246 patients with type 2 diabetes, sitagliptin 100 mg/day was generally well tolerated in clinical trials of up to 2 years in duration.

The acyclic CB1R inverse agonist taranabant mediates weight loss by increasing energy expenditure and decreasing caloric intake

Cannabinoid 1 receptor (CB1R) inverse agonists are emerging as a potential obesity therapy. However, the physiological mechanisms by which these agents modulate human energy balance are incompletely elucidated. Here, we describe a comprehensive clinical research study of taranabant, a structurally novel acyclic CB1R inverse agonist. Positron emission tomography imaging using the selective CB1R tracer [(18)F]MK-9470 confirmed central nervous system receptor occupancy levels ( approximately 10%-40%) associated with energy balance/weight-loss effects in animals. In a 12-week weight-loss study, taranabant induced statistically significant weight loss compared to placebo in obese subjects over the entire range of evaluated doses (0.5, 2, 4, and 6 mg once per day) (p < 0.001). Taranabant treatment was associated with dose-related increased incidence of clinical adverse events, including mild to moderate gastrointestinal and psychiatric effects. Mechanism-of-action studies suggest that engagement of the CB1R by taranabant leads to weight loss by reducing food intake and increasing energy expenditure and fat oxidation.

Safety and tolerability of sitagliptin in patients with type 2 diabetes: a pooled analysis

BackgroundSitagliptin, a highly selective dipeptidyl peptidase-4 inhibitor, is the first in a new class of oral antihyperglycemic agents (AHAs) for the treatment of patients with type 2 diabetes. Type 2 diabetes is a life-long disease requiring chronic treatment and management. Therefore, robust assessment of the long-term safety and tolerability of newer therapeutic agents is of importance. The purpose of this analysis was to assess the safety and tolerability of sitagliptin by pooling 12 large, double-blind, Phase IIb and III studies up to 2 years in duration. Methods: This analysis included 6139 patients with type 2 diabetes receiving either sitagliptin 100 mg/day (N = 3415) or a comparator agent (placebo or an active comparator) (N = 2724; non-exposed group). The 12 studies from which this pooled population was drawn represent the double-blind, randomized, Phase IIB and III studies that included patients treated with the clinical dose of sitagliptin (100 mg/day) for at least 18 weeks up to 2 years and that were available in a single safety database as of November 2007. These 12 studies assessed sitagliptin as monotherapy, initial combination therapy with metformin, or add-on combination therapy with other oral AHAs (metformin, pioglitazone, sulfonylurea, sulfonylurea + metformin, or metformin + rosiglitazone). Patients in the non-exposed group were taking placebo, pioglitazone, metformin, sulfonylurea, sulfonylurea + metformin, or metformin + rosiglitazone. This safety analysis used patient-level data from each study to evaluate clinical and laboratory adverse experiences.ResultsFor clinical adverse experiences, the incidence rates of adverse experiences overall, serious adverse experiences, and discontinuations due to adverse experiences were similar in the sitagliptin and non-exposed groups. The incidence rates of specific adverse experiences were also generally similar in the two groups, with the exception of an increased incidence rate of hypoglycemia observed in the non-exposed group. The incidence rates of drug-related adverse experiences overall and discontinuations due to drug-related adverse experiences were higher in the non-exposed group, primarily due to the increased incidence rate of hypoglycemia in this group. For cardiac- and ischemia-related adverse experiences (including serious events), there were no meaningful between-group differences. No meaningful differences between groups in laboratory adverse experiences, either summary measures or specific adverse experiences, were observed.ConclusionIn patients with type 2 diabetes, sitagliptin 100 mg/day was well tolerated in clinical trials up to 2 years in duration.

Missing Data in Randomized Clinical Trials for Weight Loss: Scope of the Problem, State of the Field, and Performance of Statistical Methods

Background Dropouts and missing data are nearly-ubiquitous in obesity randomized controlled trails, threatening validity and generalizability of conclusions. Herein, we meta-analytically evaluate the extent of missing data, the frequency with which various analytic methods are employed to accommodate dropouts, and the performance of multiple statistical methods. Methodology/Principal Findings We searched PubMed and Cochrane databases (2000–2006) for articles published in English and manually searched bibliographic references. Articles of pharmaceutical randomized controlled trials with weight loss or weight gain prevention as major endpoints were included. Two authors independently reviewed each publication for inclusion. 121 articles met the inclusion criteria. Two authors independently extracted treatment, sample size, drop-out rates, study duration, and statistical method used to handle missing data from all articles and resolved disagreements by consensus. In the meta-analysis, drop-out rates were substantial with the survival (non-dropout) rates being approximated by an exponential decay curve (e−λt) where λ was estimated to be .0088 (95% bootstrap confidence interval: .0076 to .0100) and t represents time in weeks. The estimated drop-out rate at 1 year was 37%. Most studies used last observation carried forward as the primary analytic method to handle missing data. We also obtained 12 raw obesity randomized controlled trial datasets for empirical analyses. Analyses of raw randomized controlled trial data suggested that both mixed models and multiple imputation performed well, but that multiple imputation may be more robust when missing data are extensive. Conclusion/Significance Our analysis offers an equation for predictions of dropout rates useful for future study planning. Our raw data analyses suggests that multiple imputation is better than other methods for handling missing data in obesity randomized controlled trials, followed closely by mixed models. We suggest these methods supplant last observation carried forward as the primary method of analysis.

The incidence of hypoglycaemia in Muslim patients with type 2 diabetes treated with sitagliptin or a sulphonylurea during Ramadan: a randomised trial

Aims:  To compare the incidence of symptomatic hypoglycaemia in fasting Muslim patients with type 2 diabetes treated with sitagliptin or a sulphonylurea during Ramadan.

Potent and Selective Agonism of the Melanocortin Receptor 4 With MK-0493 Does Not Induce Weight Loss in Obese Human Subjects: Energy Intake Predicts Lack of Weight Loss Efficacy

MK‐0493 is a novel, potent, and selective agonist of the melanocortin receptor 4 (MC4R), one of the best‐validated genetic targets and considered one of the most promising for the development of antiobesity therapeutics. An ad libitum energy‐intake model was qualified with excellent reproducibility: the geometric mean ratio (GMR) with 95% confidence interval (CI) for total energy intake over a period of 24 h for 30 mg sibutramine/placebo was 0.82 (0.76, 0.88), and for 10 mg sibutramine/placebo it was 0.98 (0.91, 1.05). MK‐0493 showed a small and marginally significant effect on 24‐h energy intake, whereas 30 mg of sibutramine caused a significant reduction in total 24‐h energy intake; specifically, the GMR (95% CI) for 30 mg sibutramine/placebo was 0.79 (0.74, 0.85). MK‐0493 was associated with modest weight reduction from baseline but had only small, statistically insignificant effects relative to placebo after 12 weeks in a fixed‐dose study and also after 18 weeks of stepped‐titration dosing. We conclude that agonism of MC4R is not likely to represent a viable approach to the development of antiobesity therapeutics.

Single- and Multiple-Dose Pharmacokinetics of Etoricoxib, a Selective Inhibitor of Cyclooxygenase-2, in Man

The single‐ and multiple‐dose pharmacokinetics of etoricoxib, a selective inhibitor of cyclooxygenase‐2, were examined in two clinical studies. Single‐dose pharmacokinetics—including dose proportionality, absolute bioavailability of the highest dose‐strength (120‐mg) tablet, and the effect of a high‐fat meal on the bioavailability of that tablet—were investigated in a two‐part, open, balanced crossover study in two panels of healthy subjects (12 per panel). Steady‐state pharmacokinetics were investigated in an open‐label study in which 24 healthy subjects were administered 120‐mg single and multiple (once daily for 10 days) oral doses of etoricoxib tablets. The pharmacokinetics of etoricoxib were found to be consistent with linearity through doses at least twofold greater than the highest anticipated clinical dose of 120 mg. Etoricoxib administered as a tablet was rapidly and completely absorbed and available; the absolute bioavailability was estimated to be 100%. A high‐fat meal decreased the rate of absorption without affecting the extent of absorption of etoricoxib; therefore, etoricoxib can be dosed irrespective of food. Steady‐state pharmacokinetics of etoricoxib, achieved following 7 days of once‐daily dosing, were found to be reasonably predicted from single doses. The accumulation ratio averaged 2.1, and the corresponding accumulation t1/2 averaged 22 hours, supporting once‐daily dosing. Etoricoxib was generally well tolerated.

Proof of Concept: A PhRMA Position Paper With Recommendations for Best Practice

Proof of concept (POC) may be defined as the earliest point in the drug development process at which the weight of evidence suggests that it is “reasonably likely” that the key attributes for success are present and the key causes of failure are absent. POC is multidimensional but is focused on attributes that, if not addressed, represent a threat to the success of the project in crucial areas such as safety, efficacy, pharmaceutics, and commercial and regulatory issues. The appropriate weight of evidence is assessed through the use of mathematical models and by evaluating the consequences of advancing a candidate drug that is not safe, effective, or commercially viable, vs. failing to advance a candidate that possesses these attributes. Tools for POC include biomarkers, targeted populations, pharmacokinetic (PK)/pharmacodynamic (PD) modeling, simulation, and adaptive study designs. Challenges to the success of POCs include a shortage of skilled personnel, failure to integrate multiple disciplines and information, and the demand made by organizations for certainty.

Effect of NPY5R antagonist MK-0557 on weight regain after very-low-calorie diet-induced weight loss

Objective: To evaluate whether MK‐0557, a highly selective, orally administered neuropeptide Y Y5 receptor antagonist, could limit weight regain after very‐low‐calorie diet (VLCD)‐induced weight loss.

Hypoglycaemia in sulphonylurea-treated subjects with type 2 diabetes undergoing Ramadan fasting: a five-country observational study

Abstract Objectives: To determine the incidence of hypoglycaemia during Ramadan in Muslim subjects with type 2 diabetes treated with a sulphonylurea. Methods: In an observational study, eligible subjects were Muslims with type 2 diabetes (age ≥18 years) who were treated with glimepiride, gliclazide, or glibenclamide with or without metformin and who expressed their intention to fast during Ramadan in 2009. Subjects were recruited by clinicians in India, Malaysia, Israel, the United Arab Emirates (UAE), and Saudi Arabia. Each day during Ramadan, patients completed diary cards, which collected information regarding hypoglycaemic symptoms and complications, time from last meal and from last medication, self-monitored blood glucose measurements, and need for assistance. The overall incidence of symptomatic hypoglycaemia recorded during Ramadan was the primary endpoint of interest. Results: Of the enrolled subjects (N = 1397), 1378 returned their diary cards at study end and were included in the analysis. Overall, 89% of subjects who expressed their intention to fast prior to Ramadan reported that they observed the fast during Ramadan. A total of 271 subjects (19.7%) experienced one or more symptomatic hypoglycaemic events during Ramadan, with incidences of 25.6%, 16.8%, and 14.0% observed in subjects treated with glibenclamide, glimepiride, and gliclazide, respectively. By country, the highest incidence of hypoglycaemia was reported by subjects from Israel (40%) followed by those from Malaysia (24%), the UAE (18%), India (13%), and Saudi Arabia (10%). The overall incidence of severe hypoglycaemic events (i.e., events requiring medical or non-medical assistance) was 6.7%, with the highest incidence occurring in the glibenclamide group. Limitations: This was an observational study and as such subjects were not randomised to treatments. While baseline measures appeared comparable, it is possible that differences in measured and unmeasured patient characteristics (e.g., measures of glycaemic control) could partially explain these results. Lastly, no inferential testing was performed on the comparisons between sulphonylurea types and/or countries. Conclusions: In this five-country observational study, nearly 20% of sulphonylurea-treated Muslim subjects with type 2 diabetes experienced symptomatic hypoglycaemia while fasting during Ramadan, with variations across sulphonylureas and countries.