Ronald B. Langdon

Efficacy and safety of sitagliptin added to ongoing metformin therapy in patients with type 2 diabetes

ABSTRACT Objective: The purpose of this study was to evaluate the efficacy and safety of sitagliptin as an add-on to metformin therapy in patients with moderately severe (hemoglobin A1c ≥ 8.0% and ≤ 11.0%) type 2 diabetes mellitus (T2DM). Research design and methods: This was a multinational, randomized, placebo-controlled, parallel-group, double-blind study conducted in 190 patients with T2DM. After ≥ 6 weeks of stable metformin monotherapy (≥ 1500 mg/day), patients were randomized to either the addition of sitagliptin 100 mg once daily or placebo to ongoing metformin for 30 weeks. Main outcome measures: The primary efficacy endpoint was reduction in hemoglobin A1c (HbA1c) measured after 18 weeks of sitagliptin treatment. Key secondary endpoints included reduction in fasting plasma glucose (FPG) and 2-hour (2-h) postprandial plasma glucose (PPG) at 18 weeks, and HbA1c at 30 weeks. The proportion of patients meeting the goal of HbA1c < 7.0% was also analyzed. Results: Sitagliptin significantly reduced HbA1c, FPG, and 2-h PPG, compared with placebo (all p < 0.001). The net improvement in HbA1c was –1.0% at both 18 and 30 weeks, and a significantly greater proportion of patients treated with sitagliptin achieved HbA1c < 7.0% by the end of the study (22.1% vs. 3.3%, p < 0.001). Sitagliptin was well-tolerated. Compared with placebo, sitagliptin had a neutral effect on body weight and did not significantly increase the risk of hypoglycemia or gastrointestinal adverse events. Conclusions: Addition of sitagliptin 100 mg once daily to ongoing metformin therapy was well-tolerated and resulted in significant glycemic improvement in patients with moderately severe T2DM who were treated for 30 weeks. Trial registration: ClinicalTrials.gov identifier: NCT00337610.

Efficacy and safety of sitagliptin in the treatment of patients with type 2 diabetes in China, India, and Korea

The efficacy and safety of sitagliptin as monotherapy were evaluated in Chinese, Indian, and Korean patients with type 2 diabetes inadequately controlled by diet and exercise. In a randomized, placebo-controlled, double-blind, 18-week trial, 530 patients with HbA(1c) >or=7.5% and <or=11.0% (mean baseline 8.7%) received sitagliptin 100mg once daily or placebo. Compared with placebo, sitagliptin significantly (p<0.001) reduced mean HbA(1c) (-1.0%), fasting plasma glucose (-1.7 mmol/L), and 2-h postprandial glucose (-3.1 mmol/L), and a significantly (p<0.001) greater proportion of sitagliptin-treated versus placebo-treated patients achieved HbA(1c) <7% (20.6% versus 5.3%, respectively) at study end. Efficacy of sitagliptin was demonstrated in each country. Sitagliptin was generally well-tolerated. Clinical adverse events (AEs) were reported in 23.3% and 15.2% of sitagliptin-treated and placebo-treated patients, respectively. The difference was primarily due to increased gastrointestinal AEs in the sitagliptin group, most of which were mild and resolved on study drug. Serious AEs, discontinuations due to AEs, and drug-related AEs occurred with a low incidence in both groups. No hypoglycemia was reported. In conclusion, in this study, sitagliptin monotherapy for 18 weeks significantly improved glycemic control and was well-tolerated in patients with type 2 diabetes from China, India, and Korea.

Efficacy and tolerability of sitagliptin monotherapy in elderly patients with type 2 diabetes: a randomized, double-blind, placebo-controlled trial

Abstract Objective: Type 2 diabetes in the elderly is an important and insufficiently studied public health problem. This study evaluated sitagliptin monotherapy in patients with type 2 diabetes aged ≥65 years. Research design and methods: This was a randomized, double-blind, placebo-controlled, parallel-group study conducted at 52 sites in the United States. Patients were treated with once-daily sitagliptin (100 or 50 mg, depending on renal function) or placebo for 24 weeks. Key endpoints included change from baseline in glycated hemoglobin (HbA1c), 2-hour post-meal glucose (2-h PMG) and fasting plasma glucose (FPG) at week 24, and average blood glucose on treatment days 3 and 7. Clinical trial registration: NCT00305604. Results: Among randomized patients (N = 206), mean age was 72 years and mean baseline HbA1c was 7.8%. At week 24, HbA1c decreased by 0.7%, 2-h PMG by 61 mg/dL, and FPG by 27 mg/dL in sitagliptin-treated patients compared with placebo (all p < 0.001). On day 3 of treatment, mean average blood glucose was decreased from baseline by 20.4 mg/dL in sitagliptin-treated patients compared with placebo (p < 0.001). In subgroups defined by baseline HbA1c <8.0% (n = 132), ≥8.0% to <9.0% (n = 42), and ≥9.0% (n = 18), the placebo-adjusted reductions in HbA1c with sitagliptin treatment were 0.5%, 0.9%, and 1.6%, respectively. Patients in the sitagliptin and placebo groups had similar rates of adverse events overall (46.1% and 52.9%, respectively); serious adverse events were reported in 6.9% and 13.5%, respectively. No adverse events of hypoglycemia were reported. Potential study limitations include a relatively small number of patients with more severe hyperglycemia (HbA1c ≥9.0%) and the exclusion of patients with severe renal insufficiency. Conclusion: In this study, sitagliptin treatment significantly and rapidly improved glycemic measures and was well tolerated in patients aged ≥65 years with type 2 diabetes.

Montelukast in the treatment of allergic rhinitis: an evidence-based review.

Cysteinyl-leukotrienes (CysLTs) are endogenous mediators of inflammation and play an important role in allergic airway disease by stimulating bronchoconstriction, mucus production, mucosal oedema and inflammation, airway infiltration by eosinophils, and dendritic cell maturation that prepares for future allergic response. Montelukast inhibits these actions by blocking type 1 CysLT receptors found on immunocytes, smooth muscle and endothelium in the respiratory mucosa. Initially developed as a treatment for asthma, montelukast has more recently found use in the treatment of allergic rhinitis (AR).We conducted a systematic review of studies that have evaluated montelukast in the treatment of seasonal AR (SAR) and perennial AR (PAR), with and without concomitant asthma. Primary consideration was given to large, randomised, placebo-controlled, double-blind clinical trials in which AR endpoints were assessed and the use of concurrent treatments for AR was excluded. Eight such studies were found in the literature. The primary endpoint in these was daytime nasal symptom severity represented by a composite score derived from individual self-ratings of nasal congestion, rhinorrhoea, nasal pruritus and sneezing. Secondary endpoints have included these individual nasal symptom scores, additional scores for eye, ear and throat symptoms, the impact of rhinitis on quality of sleep, global evaluations of outcome by patients and physicians, and measures of the severity of concomitant asthma.A general outcome was that patients treated with montelukast had significantly greater improvements in their symptoms of SAR and PAR than did patients who were given a placebo. As monotherapy, montelukast exhibited efficacy similar to that of loratadine, but less than that of the intranasally administered corticosteroid fluticasone propionate. The use of montelukast in combination with antihistamines such as loratadine or cetirizine has generally resulted in greater efficacy than when these agents were used alone, and in some studies has produced results comparable with intranasally applied corticosteroids. In patients with AR comorbid with asthma, montelukast treatment has resulted in significant improvements in both, compared with placebo. Montelukast is well tolerated and has a favourable safety profile; adverse events have occurred at similar frequencies in patients taking either montelukast or placebo.Montelukast provides an effective and well tolerated oral treatment for allergic airway inflammation in patients with SAR or PAR without asthma, and in patients in whom AR is comorbid with asthma.

A Phase I Pharmacokinetic and Pharmacodynamic Study of Dalotuzumab (MK-0646), an Anti-Insulin-like Growth Factor-1 Receptor Monoclonal Antibody, in Patients with Advanced Solid Tumors

Purpose: Insulin-like growth factor-1 receptor (IGF-1R) mediates cellular processes in cancer and has been proposed as a therapeutic target. Dalotuzumab (MK-0646) is a humanized IgG1 monoclonal antibody that binds to IGF-1R preventing receptor activation. This study was designed to evaluate the safety and tolerability of dalotuzumab, determine the pharmacokinetic (PK) and pharmacodynamic (PD) profiles, and identify a recommended phase II dose. Experimental Design: Patients with tumors expressing IGF-1R protein were allocated to dose-escalating cohorts of three or more patients each and received intravenous dalotuzumab weekly, every 2 or 3 weeks. Plasma was collected for PK analysis. Paired baseline and on-treatment skin and tumor biopsy samples were collected for PD analyses. Results: Eighty patients with chemotherapy-refractory solid tumors were enrolled. One dose-limiting toxicity was noted, but a maximum-tolerated dose was not identified. Grade 1 to 3 hyperglycemia, responsive to metformin, occurred in 15 (19%) patients. At dose levels or more than 5 mg/kg, dalotuzumab mean terminal half-life was 95 hours or more, mean Cmin was more than 25 μg/mL, clearance was constant, and serum exposures were approximately dose proportional. Decreases in tumor IGF-1R, downstream receptor signaling, and Ki67 expression were observed. 18F-Fluorodeoxy-glucose positron emission tomography metabolic responses occurred in three patients. One patient with Ewings sarcoma showed a mixed radiologic response. The recommended phase II doses were 10, 20, and 30 mg/kg for the weekly, every other week, and every third week schedules, respectively. Conclusions: Dalotuzumab was generally well-tolerated, exhibited dose-proportional PK, inhibited IGF-1R pathway signaling and cell proliferation in treated tumors, and showed clinical activity. The low clearance rate and long terminal half-life support more extended dosing intervals. Clin Cancer Res; 17(19); 6304–12. ©2011 AACR.

Efficacy and safety of the selective 11β-HSD-1 inhibitors MK-0736 and MK-0916 in overweight and obese patients with hypertension.

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) may be involved in several abnormalities associated with the metabolic syndrome. This study evaluated the antihypertensive efficacy and safety of two 11β-HSD1 inhibitors, MK-0736 and MK-0916, in overweight-to-obese hypertensive patients. Patients aged 18-75 years with sitting diastolic blood pressure (SiDBP) 90-104 mm Hg, systolic BP <160 mm Hg (after washout of prior antihypertensive medications), and BMI ≥27 to <41 kg/m(2) were randomized to receive 2 or 7 mg/d MK-0736, 6 mg/d MK-0916, or placebo for 12 weeks (n = 51-54/group). Patients with BMI ≥20 to <27 kg/m(2) received 6 mg/d MK-0916 or placebo for 24 weeks (n = 19/group). The primary endpoint was placebo-adjusted change from baseline in trough SiDBP in patients treated for 12 weeks with 7 mg/d MK-0736. The primary endpoint was not met (placebo-adjusted reduction = 2.2 mm Hg; P = .157). With 7 mg/d MK-0736, placebo-adjusted LDL-C decreased by 12.3%, high-density lipoprotein cholesterol by 6.3%, and body weight by 1.4 kg. Both 11β-HSD1 inhibitors were generally well tolerated. In overweight-to-obese patients with hypertension, reduction in SiDBP with MK-0736 was not statistically significant. Nonetheless, MK-0736 was well tolerated and did appear to modestly improve other BP endpoints, LDL-C, and body weight.

Anti-diabetic efficacy and impact on amino acid metabolism of GRA1, a novel small-molecule glucagon receptor antagonist.

Hyperglucagonemia is implicated in the pathophysiology of hyperglycemia. Antagonism of the glucagon receptor (GCGR) thus represents a potential approach to diabetes treatment. Herein we report the characterization of GRA1, a novel small-molecule GCGR antagonist that blocks glucagon binding to the human GCGR (hGCGR) and antagonizes glucagon-induced intracellular accumulation of cAMP with nanomolar potency. GRA1 inhibited glycogenolysis dose-dependently in primary human hepatocytes and in perfused liver from hGCGR mice, a transgenic line of mouse that expresses the hGCGR instead of the murine GCGR. When administered orally to hGCGR mice and rhesus monkeys, GRA1 blocked hyperglycemic responses to exogenous glucagon. In several murine models of diabetes, acute and chronic dosing with GRA1 significantly reduced blood glucose concentrations and moderately increased plasma glucagon and glucagon-like peptide-1. Combination of GRA1 with a dipeptidyl peptidase-4 inhibitor had an additive antihyperglycemic effect in diabetic mice. Hepatic gene-expression profiling in monkeys treated with GRA1 revealed down-regulation of numerous genes involved in amino acid catabolism, an effect that was paralleled by increased amino acid levels in the circulation. In summary, GRA1 is a potent glucagon receptor antagonist with strong antihyperglycemic efficacy in preclinical models and prominent effects on hepatic gene-expression related to amino acid metabolism.

Effects of peripherally administered neuromedin U on energy and glucose homeostasis.

Neuromedin U (NMU) is a highly conserved peptide reported to modulate energy homeostasis. Pharmacological studies have shown that centrally administered NMU inhibits food intake, reduces body weight, and increases energy expenditure. NMU-deficient mice develop obesity, whereas transgenic mice overexpressing NMU become lean and hypophagic. Two high-affinity NMU receptors, NMUR1 and NMUR2, have been identified. NMUR1 is found primarily in the periphery and NMUR2 primarily in the brain, where it mediates the anorectic effects of centrally administered NMU. Given the broad expression pattern of NMU, we evaluated whether peripheral administration of NMU has effects on energy homeostasis. We observed that acute and chronic peripheral administration of NMU in rodents dose-dependently reduced food intake and body weight and that these effects required NMUR1. The anorectic effects of NMU appeared to be partly mediated by vagal afferents. NMU treatment also increased core body temperature and metabolic rate in mice, suggesting that peripheral NMU modulates energy expenditure. Additionally, peripheral administration of NMU significantly improved glucose excursion. Collectively, these data suggest that NMU functions as a peripheral regulator of energy and glucose homeostasis and the development of NMUR1 agonists may be an effective treatment for diabetes and obesity.

Evaluation of pharmacokinetic parameters and dipeptidyl peptidase-4 inhibition following single doses of sitagliptin in healthy, young Japanese males.

AIMS Sitagliptin is a selective inhibitor of dipeptidyl peptidase-4 (DPP-4) used to treat type 2 diabetes. The present aim was to evaluate pharmacokinetic (PK), pharmacodynamic (PD) and safety characteristics of sitagliptin following single doses in healthy, young Japanese males. METHODS In this alternating two-panel, randomized, controlled double-blind study, six healthy Japanese male subjects (aged 20-46 years) in each panel received single oral doses of 5-400mg sitagliptin and two received placebo. Plasma and urine drug concentrations were measured from 0-48h post dose and plasma DPP-4 inhibition from 0-24h post dose. The results were compared with historical data from young, healthy non-Japanese males. RESULTS Plasma concentrations of sitagliptin increased approximately in proportion to dose; maximum concentrations occurred 2-6h post-dose. The mean apparent terminal half-life for plasma sitagliptin was 9-14h, with the half-life slightly decreasing as the dose increased. The mean dose fraction excreted unchanged in the urine was 0.73-1.00. Ingestion of a traditional Japanese breakfast prior to dosing had only a minor effect on PK parameters. After correction for dilution and competition effects during assay, doses of sitagliptin ≥50mg resulted in weighted average DPP-4 inhibition from 0-24h post-dose >94% (without correction, >78%). No clinically meaningful differences in PK and DPP-4 inhibition parameters were found between Japanese and non-Japanese subjects. Sitagliptin was generally well tolerated and there were no serious adverse experiences or episodes of hypoglycaemia. CONCLUSIONS The PK and PD findings from this study are consistent with once daily dosing of sitagliptin in Japanese patients with type 2 diabetes.

Efficacy and safety of sitagliptin added to ongoing metformin and rosiglitazone combination therapy in a randomized placebo-controlled 54-week trial in patients with type 2 diabetes.

Background:  New therapeutic approaches are needed to improve glycemic control in patients with type 2 diabetes (T2D), a progressive disorder that often requires combination therapy. The present study assessed the efficacy and safety of sitagliptin as add‐on therapy to metformin and rosiglitazone in patients with T2D.