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Sitagliptin and glipizide added to metformin provided similar degrees of glycemic efficacy in patients with type 2 diabetes with inadequate glycemic control on metformin monotherapy at 1 year; however, significantly more patients in the sitagliptin group achieved an A1C reduction of >0.5% without hypoglycemia and without an increase in body weight. [ABSTRACT FROM AUTHOR]

Missing data is unavoidable in longitudinal clinical trials, and outcomes are not always normally distributed. In the presence of outliers or heavy-tailed distributions, the conventional multiple imputation with the mixed model with repeated measures analysis of the average treatment effect (ATE) based on the multivariate normal assumption may produce bias and power loss. Control-based imputation (CBI) is an approach for evaluating the treatment effect under the assumption that participants in both the test and control groups with missing outcome data have a similar outcome profile as those with an identical history in the control group. We develop a robust framework to handle non-normal outcomes under CBI without imposing any parametric modeling assumptions. Under the proposed framework, sequential weighted robust regressions are applied to protect the constructed imputation model against non-normality in the covariates and the response variables. Accompanied by the subsequent mean imputation and robust model analysis, the resulting ATE estimator has good theoretical properties in terms of consistency and asymptotic normality. Moreover, our proposed method guarantees the analysis model robust-ness of the ATE estimation in the sense that its asymptotic results remain intact even when the analysis model is misspecified. The superiority of the proposed robust method is demonstrated by comprehensive simulation studies and an AIDS clinical trial data application.

Objective: To assess the efficacy and safety of sitagliptin in youth with type 2 diabetes (T2D) inadequately controlled with metformin ± insulin., Study Design: Data were pooled from two 54-week, double-blind, randomized, placebo-controlled studies of sitagliptin 100 mg daily or placebo added onto treatment of 10- to 17-year-old youth with T2D and inadequate glycemic control on metformin ± insulin. Participants (N = 220 randomized and treated) had HbA1c 6.5%-10% (7.0%-10% if on insulin), were overweight/obese at screening or diagnosis and negative for pancreatic autoantibodies. The primary endpoint was change from baseline in HbA1c at Week 20., Results: Treatment groups were well balanced at baseline (mean HbA1c = 8.0%, BMI = 30.9 kg/m 2 , age = 14.4 years [44.5% <15], 65.9% female). The dose of background metformin was >1500 mg/day for 71.8% of participants; 15.0% of participants were on insulin therapy. At Week 20, LS mean changes from baseline (95% CI) in HbA1c for sitagliptin/metformin and placebo/metformin were -0.58% (-0.94, -0.22) and -0.09% (-0.43, 0.26), respectively; difference = -0.49% (-0.90, -0.09), p = 0.018; at Week 54 the LS mean (95% CI) changes were 0.35% (-0.48, 1.19) and 0.73% (-0.08, 1.54), respectively. No meaningful differences between the adverse event profiles of the treatment groups emerged through Week 54., Conclusions: These results do not suggest that addition of sitagliptin to metformin provides durable improvement in glycemic control in youth with T2D. In this study, sitagliptin was generally well tolerated with a safety profile similar to that reported in adults. (ClinicalTrials.gov: NCT01472367, NCT01760447; EudraCT: 2011-002529-23/2014-003583-20, 2012-004035-23)., (© 2021 John Wiley & Sons Ltd.)

Objective: To assess the efficacy and safety of DPP-4 inhibition with sitagliptin in youth with type 2 diabetes (T2D)., Study Design: This was a 54-week, double-blind, randomized, controlled clinical trial evaluating the safety and efficacy of DPP-4 inhibition with sitagliptin 100 mg once daily as initial oral therapy in youth with T2D. The 190 participants, aged 10-17 years, had HbA1c 6.5%-10% (7.0%-10% if on insulin). All were negative for pancreatic autoantibodies and overweight/obese at screening or diagnosis. The trial was placebo controlled for the first 20 weeks, after which metformin replaced placebo. The primary efficacy endpoint was change from baseline in HbA1c at Week 20., Results: Treatment groups were well balanced at baseline (mean ± SD HbA1c = 7.5% ± 1.0, BMI percentile = 97.1% ± 6.8, age = 14.0 years ± 2.0 [57.4% <15], 60.5% female). At Week 20, least squares mean changes from baseline in HbA1c were -0.01% (sitagliptin) and 0.18% (placebo); between-group difference (95% CI) = -0.19% (-0.68, 0.30), p = 0.448. At Week 54, the changes in HbA1c were 0.45% (sitagliptin) and -0.11 (placebo/metformin). There were no notable between-group differences in the adverse event profiles through Week 54., Conclusions: DPP-4 inhibition with sitagliptin did not provide significant improvement in glycemic control. In this study, sitagliptin was generally well tolerated with a safety profile similar to that reported in adults. (ClinicalTrials.gov: NCT01485614; EudraCT: 2011-002528-42)., (© 2021 John Wiley & Sons Ltd.)

Aims: To compare the effects of continuing versus discontinuing sitagliptin when initiating and intensively titrating insulin glargine., Materials and Methods: Eligible patients had inadequately controlled type 2 diabetes on metformin (≥1500 mg/d) in combination with a dipeptidyl peptidase-4 (DPP-4) inhibitor and/or a sulphonylurea. Those on metformin + sitagliptin were directly randomized; all others were switched to metformin + sitagliptin (discontinuing other DPP-4 inhibitors and sulphonylureas) and stabilized during a run-in period. At randomization, patients were allocated to continuing sitagliptin or discontinuing sitagliptin, with both groups initiating insulin glargine and titrating to a target fasting glucose of 4.0 to 5.6 mmol/L., Results: A total of 743 participants (mean glycated haemoglobin [HbA1c] 72.6 mmol/mol [8.8%], disease duration 10.8 years), were treated. After 30 weeks, the mean HbA1c and least squares (LS) mean change from baseline in HbA1c were 51.4 mmol/mol (6.85%) and -20.5 mmol/mol (-1.88%) in the sitagliptin group and 56.4 mmol/mol (7.31%) and -15.5 mmol/mol (-1.42%) in the placebo group; the difference in LS mean changes from baseline HbA1c was -5.0 mmol/mol (-0.46%; P < 0.001). The percentage of participants with HbA1c <53 mmol/mol (<7.0%) was higher (54% vs. 35%) and the mean daily insulin dose was lower (53 vs. 61 units) in the sitagliptin group. Despite lower HbA1c, event rates and incidences of hypoglycaemia were not higher in the sitagliptin group. Adverse events overall and changes from baseline in body weight were similar between the two treatment groups., Conclusion: When initiating insulin glargine therapy, continuation of sitagliptin, compared with discontinuation, resulted in a clinically meaningful greater reduction in HbA1c without an increase in hypoglycaemia. ClinicalTrials.gov Identifier: NCT02738879., (© 2018 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.)

Aim: To compare the efficacy and safety of MK-1293 insulin glargine (Mk-Gla) and Lantus (Sa-Gla) in people with type 2 diabetes mellitus (T2DM)., Materials and Methods: This Phase 3, randomized, active-controlled, open-label, 24-week clinical trial (ClinicalTrials.gov number NCT02059187) enrolled 531 participants with T2DM (HbA1c ≤11.0%) either eligible for or currently taking basal insulin (≥10 U/day). Participants were randomized 1:1 to once-daily Mk-Gla (n = 263) or Sa-Gla (n = 263). Titration of insulin was guided by a fasting plasma glucose (FPG)-based dosing algorithm. The primary efficacy objective was to demonstrate the non-inferiority of change from baseline in HbA1c (margin of 0.40% [4.4 mmol/mol]) with Mk-Gla versus Sa-Gla after 24 weeks. The primary safety objective was anti-insulin antibody development after 24 weeks., Results: For Mk-Gla and Sa-Gla, the least squares (LS) mean HbA1c change from baseline (95% CI) was -1.28 (-1.41, -1.15)% (-14.0 [-15.4, -12.6] mmol/mol) and -1.30 (-1.43, -1.18)% (-14.2 [-15.6, -12.8] mmol/mol). The LS mean HbA1c difference (Mk-Gla minus Sa-Gla) was 0.03 (-0.12, 0.18)% (0.3 [-1.4, 1.9] mmol/mol), meeting non-inferiority and equivalence (secondary objective) criteria. Insulin doses, FPG, and seven-point plasma glucose profiles were similar between groups. Safety and tolerability, including anti-insulin antibody responses, hypoglycaemia, adverse events and body weight, were similar between insulins. The efficacy and safety of Mk-Gla and Sa-Gla were similar both in participants who were insulin-treated or insulin-naïve at baseline., Conclusions: Mk-Gla and Sa-Gla demonstrated similar efficacy and safety over 24 weeks of treatment in people with T2DM., (© 2018 John Wiley & Sons Ltd.)

Aim: To compare the efficacy and safety of MK-1293 insulin glargine (Mk-Gla; 100 U/mL) with originator insulin glargine, Lantus (Sa-Gla), in people with type 1 diabetes mellitus (T1DM)., Materials and Methods: This phase 3, randomized, active-controlled, open-label, 52-week study (ClinicalTrials.gov NCT02059161) enrolled 508 people with T1DM (HbA1c ≤11.0%; 97 mmol/mol) taking basal and prandial insulin. Participants were randomized 1:1 to once-daily Mk-Gla (n = 245) or Sa-Gla (n = 263). Dose titration of basal insulin was by a pre-breakfast plasma glucose dosing algorithm. The primary efficacy objective was assessment of the non-inferiority of HbA1c change from baseline (margin of 0.40% [4.4 mmol/mol]) for Mk-Gla compared with Sa-Gla over 24 weeks. The primary safety objective was assessment of anti-insulin antibody development over 24 weeks., Results: The least squares (LS) mean HbA1c change from baseline at week 24 was -0.62 (95% CI -0.79, -0.45)% (-6.8 [-8.7, -4.9] mmol/mol) and -0.66 (-0.82, -0.50)% (-7.2 [-9.0, -5.4] mmol/mol) for Mk-Gla and Sa-Gla. The LS mean HbA1c difference was 0.04 (-0.11, 0.19)% (0.4 [-1.2, 2.0] mmol/mol) for Mk-Gla minus Sa-Gla, meeting the primary and secondary objective criteria for non-inferiority and equivalence. Week 24 mean insulin glargine dose for Mk-Gla and Sa-Gla was 0.46 and 0.48 U/kg, respectively. Similarity of HbA1c response and basal insulin dose trajectory persisted over the 52 weeks. Safety and tolerability, including anti-insulin antibody responses, hypoglycaemia, adverse events and body weight, were similar between insulins over the 52-week study duration., Conclusions: Mk-Gla and Sa-Gla exhibited similar efficacy and safety over 52 weeks in people with T1DM. ClinicalTrials.gov: NCT02059161., (© 2018 John Wiley & Sons Ltd.)

Background: Type 2 diabetes mellitus (T2DM) treatment generally requires multiple antihyperglycemic agents. When diet, exercise, and treatment with sulfonylurea and metformin do not achieve glycemic goals, several options are available. The present study evaluated the efficacy and tolerability of sitagliptin 100 mg/day added to therapy with sulfonylurea and metformin., Methods: Patients with HbA1c ≥7.5% and ≤10.5% while on a sulfonylurea and metformin were randomized 1: 1 to sitagliptin 100 mg/day or placebo for 24 weeks. At Week 24, patients in the placebo group switched to pioglitazone 30 mg/day and both groups continued treatment for another 30 weeks., Results: Of 427 patients randomized, 339 (79.4%) completed the study. At Week 24, significantly greater (P < 0.001) mean reductions from baseline were seen in the sitagliptin versus placebo group for HbA1c (-0.84% vs -0.16%, respectively), 2-h post-meal glucose (-2.0 vs -0.2 mmol/L, respectively) and fasting plasma glucose (-0.7 vs 0.3 mmol/L, respectively). At Week 54, improvements in glycemic control continued. At Week 24, the incidence of adverse events (AEs) was numerically greater with sitagliptin than placebo, primarily because of a higher incidence of hypoglycemia. At Week 54, the incidence of AEs was similar in both groups, primarily because of a higher incidence of hypoglycemia and edema in the placebo/pioglitazone group after Week 24. The only meaningful change in body weight was an increase in the placebo/pioglitazone group at Week 54., Conclusions: In this study, sitagliptin 100 mg/day was generally well tolerated and provided improvement in glycemic control when added to the combination of sulfonylurea and metformin in patients with T2DM., (© 2016 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.)

Introduction: The results of a clinical trial to evaluate the efficacy and safety of initial combination therapy with sitagliptin and metformin in Chinese patients with type 2 diabetes and inadequate glycemic control are reported here., Materials and Methods: This was a multicenter, randomized, double-blind, placebo-controlled, parallel group, 24-week clinical trial carried out in China. Patients (n = 744) with type 2 diabetes and inadequate glycemic control (glycated hemoglobin ≥7.5 and ≤11.0%) who were either drug-naïve or washed out of previous therapy were randomized in equal ratios to sitagliptin 100 mg once daily (q.d.; S100), metformin 500 mg twice daily (b.i.d.; M1000), metformin 850 mg b.i.d. (M1700), sitagliptin 50 mg b.i.d. plus metformin 500 mg b.i.d. (S100/M1000), sitagliptin 50 mg b.i.d. plus metformin 850 mg b.i.d. (S100/M1700), or placebo., Results: The mean baseline glycated hemoglobin in randomized patients was 8.7%. Least squares mean changes from baseline in glycated hemoglobin were -0.59% (placebo), -0.99% (S100), -1.29% (M1000), -1.56% (M1700), -1.67% (S100/M1000) and -1.83% (S100/M1700) (P < 0.05 for each active group vs placebo, for S100/M1700 and S100/M1000 vs S100, and for S100/M1000 vs M1000). All treatments were generally well-tolerated. The overall incidence of hypoglycemia (symptomatic or asymptomatic) was higher in the two co-administration groups (S100/M1700 and S100/M1000) compared with the placebo. The incidence of symptomatic hypoglycemia was low, and similar, across all treatment groups. The incidences of gastrointestinal adverse events were generally higher in high-dose metformin groups than in the placebo group., Conclusions: In Chinese patients with type 2 diabetes, initial combination therapy with sitagliptin and metformin was generally well-tolerated, and provided improvement in glycemic control., (© 2016 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.)

Objective: To evaluate the efficacy of once daily sitagliptin 100 mg as monotherapy or as add-on to metformin in patients with type 2 diabetes mellitus (T2DM) over 2 years of treatment., Research Design and Methods: The monotherapy analysis used pooled 104 week data from 64 patients in two randomized, double-blind trials evaluating the safety and efficacy of sitagliptin monotherapy. Data used were from patients who were randomized to sitagliptin 100 mg/day, were not on an antihyperglycemic agent at the screening visit, had baseline A1C of 7.0%-10.0%, and had Week 104 A1C measurements. The add-on to metformin analysis used pooled data from 347 patients in two randomized double-blind trials evaluating the safety and efficacy of sitagliptin + metformin combination therapy. Data used were from patients who were randomized to sitagliptin 100 mg/day + metformin ≥1500 mg/day, had baseline A1C of 7%-10%, and had Week 104 A1C measurements. Excluded from either analysis were patients who discontinued prior to 2 years (e.g., due to lack of efficacy, a need for rescue medications, or adverse experiences). Analysis endpoints were A1C, fasting plasma glucose (FPG), HOMA-β, proinsulin/insulin (P/I) ratio, and for monotherapy, 2 hour post-meal plasma glucose (PMG)., Results: For the pooled monotherapy cohort, after 2 years of treatment, mean A1C, FPG, and 2 hour PMG decreased from baseline values of 7.9%, 156 mg/dL, and 223 mg/dL to 6.9%, 143 mg/dL, and 191 mg/dL, respectively, while HOMA-β increased from 67% to 85% and P/I ratio improved from 0.57 to 0.28. For the pooled add-on to metformin cohort, after 2 years of treatment, mean A1C and FPG decreased from baseline values of 7.7% and 160 mg/dL to 6.9% and 140 mg/dL, respectively, while HOMA-β increased from 50% to 62% and P/I ratio improved from 0.33 to 0.28. These analyses are limited in that only patients who were able to complete 104 weeks of study were included., Conclusion: In the subset of patients with T2DM who maintained and completed treatment for 2 years with sitagliptin as monotherapy or as add-on to metformin, improvements in glycemic control and measures of β-cell function were observed over the course of treatment.

Introduction: In the USA, 45% of patients with type 2 diabetes mellitus (T2DM) are elderly (≥ 65 years old). In general, use of sulfonylurea increases with patient age as does the associated risk for hypoglycaemia, and the consequences of hypoglycaemia can be more pronounced in elderly patients. Sitagliptin, a DPP-4 inhibitor, improves glycaemic control in adult patients of all ages with T2DM, with a low risk of hypoglycaemia when used alone or in combination with other antidiabetic agents that are not generally associated with hypoglycaemia when used independently., Methods: In a post hoc analysis, pooled data from elderly patients who participated in one of three double-blind studies comparing the effects of therapy with sitagliptin (100 mg/day) vs. sulfonylurea (in titrated doses) were analysed for changes from baseline in HbA1c, fasting plasma glucose (FPG), and body weight and for the incidence of reported symptomatic hypoglycaemia. In these studies, patients on diet alone or metformin were randomised to sitagliptin or glipizide for 104 weeks (studies 1 and 2) or glimepiride for 30 weeks (study 3). The analysis included 372 elderly patients who completed a trial through 25 or 30 weeks., Results: Both HbA1c and FPG decreased from baseline with each treatment, with no statistically significant differences between treatments. A significantly lower incidence of reported hypoglycaemia was observed with sitagliptin compared with sulfonylurea (6.2% vs. 27.8%; p < 0.001). Body weight decreased significantly with sitagliptin but not with sulfonylurea. Significantly more patients on sitagliptin than on sulfonylureas achieved a composite end-point of >0.5% HbA1c reduction with no reported hypoglycaemia or increase in body weight (44.1% vs. 16.0%; p < 0.001)., Conclusion: In this analysis of elderly patients with T2DM, compared with sulfonylurea, sitagliptin provided similar glycaemic efficacy with less hypoglycaemia and with body weight loss., (© 2015 John Wiley & Sons Ltd.)

Objective: The aim of this study was to evaluate the efficacy and tolerability of sitagliptin compared with glimepiride in elderly patients with type 2 diabetes mellitus (T2DM) and inadequate glycemic control with diet and exercise alone., Methods: This was a randomized, parallel-group, multinational, non-inferiority clinical trial with an active-controlled, double-blind treatment period in which patients ≥ 65 and ≤ 85 years of age with T2DM were screened at 85 sites. Patients were randomized to once-daily sitagliptin (100 or 50 mg, depending on renal function) or glimepiride (in titrated doses) for 30 weeks. The main outcome measures were change from baseline in glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), and body weight; and the incidence of symptomatic hypoglycemia., Results: The mean baseline HbA1c was 7.8% in both the sitagliptin group (n = 197) and the glimepiride group (n = 191). After 30 weeks, the least squares (LS) mean change in HbA1c baseline was -0.32% with sitagliptin and -0.51 % with glimepiride, for a between-group difference (95% CI) of 0.19% (0.03-0.34). This result met the pre-specified criterion for declaring non-inferiority, which required that the upper 95% confidence limit lie below 0.4%. The LS mean change in FPG from baseline was -14.5 mg/dL with sitagliptin and -21.2 mg/dL with glimepiride, for a between-group difference (95% CI) of 6.7 mg/dL (0.7-12.7). The percentages of patients with adverse events of symptomatic hypoglycemia were 0.8% in the sitagliptin group and 4.7% in the glimepiride group (between-treatment difference = -3.9%, p = 0.009). The LS mean change in body weight from baseline was 0.4 kg with sitagliptin and 1.1 kg with glimepiride, for a between-group difference of -0.7 kg (p = 0.011)., Conclusion: In elderly patients with T2DM and inadequate glycemic control with diet and exercise alone, sitagliptin provided non-inferior glycemic control after 30 weeks of treatment compared with glimepiride. Compared with glimepiride, sitagliptin had a lower risk of hypoglycemia. Sitagliptin was weight-neutral; while the between-group difference in change from baseline in body weight was statistically significant, the modest difference may not be clinically meaningful., Study Identifier: ClinicalTrials.gov NCT01189890.

Introduction: The objective of this study was to assess the effect of sitagliptin on insulin dose in patients with inadequately controlled type 2 diabetes who titrate basal insulin to a target fasting glucose level after initiating sitagliptin., Methods: This was a multicenter, randomized, double-blind, placebo-controlled, 24-week clinical trial in which treatment with sitagliptin 100 mg/day or placebo was administered concurrently with insulin glargine titration, targeting a fasting glucose of 4.0-5.6 mmol/L (72-100 mg/dL). The trial randomized 660 patients with type 2 diabetes and inadequate glycemic control on insulin, with or without metformin (≥1500 mg/day) or sulfonylurea, for ≥10 weeks. Patients could remain on metformin but not sulfonylurea after randomization., Results: The increase from baseline in the daily dose of insulin was less in the sitagliptin group (N = 329) compared to placebo (N = 329) (between group difference = -4.7 IU [95% confidence interval [CI] -8.3, -1.2]; p = 0.009). Patients in the sitagliptin group had lower glycated hemoglobin (HbA1c) levels after 24 weeks (between-group difference of -0.4% [95% CI -0.6, -0.3; -4.9 mmol/mol (95% CI -6.6, -3.2)]; p < 0.001), and more patients in the sitagliptin group reached the HbA1c goal of <7.0% (53 mmol/mol), with a between-group difference of 17.3% (95% CI 10.4%, 24.1%; p < 0.001). Fewer patients in the sitagliptin group experienced an adverse event of hypoglycemia (between-group difference = -15.5%, p < 0.001)., Conclusion: Administration of sitagliptin prior to intensive titration of basal insulin glargine reduces the insulin dose requirement while providing superior glycemic control and less hypoglycemia, compared to an insulin-only regimen., Funding: Merck & Co., Inc., Kenilworth, NJ, USA.

Objective: The aim of this study was to evaluate the safety and tolerability of sitagliptin 100 mg/day in elderly patients with type 2 diabetes., Design: A post hoc pooled analysis of 25 randomized, double-blind, parallel group clinical studies with results available as of 1 December 2011., Setting: Multicenter, international clinical trials., Subjects: Patients with type 2 diabetes aged 65 years or older., Interventions: Patients were randomized to sitagliptin 100 mg/day (n = 1,261) or a comparator (n = 1,185) for 12 weeks to 2 years., Main Outcome Measures: In each study, investigators reported serious and non-serious adverse events that occurred during the study, and serious adverse events occurring within 14 days following the last dose of study drug. This analysis used patient-level data from each study to assess the exposure-adjusted incidence rates of specific adverse events that occurred following initiation of study drug., Results: Summary measures of adverse events overall were similar between the sitagliptin and non-exposed (active comparator or placebo) groups, except for higher incidences of deaths and drug-related adverse events in the non-exposed group. Incidence rates of specific adverse events were generally similar between the two groups, with the exception of hypoglycemia. A lower incidence rate of hypoglycemia was observed in the sitagliptin group compared with the non-exposed group [7.0 vs. 14.3 per 100 patient-years; difference -7.6 (95 % CI -11.2 to -4.3]), primarily due to greater use of sulfonylureas in the non-exposed group., Conclusions: In this pooled safety analysis of elderly patients with type 2 diabetes, treatment with sitagliptin 100 mg/day was generally well tolerated for up to 2 years.

Aim: To evaluate the efficacy and safety of initial combination therapy of sitagliptin 100 mg/day coadministered with all marketed doses of pioglitazone in patients with type 2 diabetes., Methods: Patients with A1c ≥7.5 and ≤11.0% were randomized among seven arms that received, once daily, 100 mg sitagliptin alone; 15, 30 or 45 mg pioglitazone alone, or 100 mg sitagliptin plus 15, 30 or 45 mg pioglitazone for 54 weeks. The primary endpoint was change from baseline in A1c at week 24. Protocol-specified analyses compared combination therapies with monotherapies at respective dose-strengths and combination of sitagliptin plus pioglitazone 30 mg with pioglitazone 45 mg monotherapy. Post-hoc analyses compared sitagliptin plus pioglitazone 15 mg with pioglitazone monotherapy at the two higher doses., Results: Initial combination therapy with sitagliptin and pioglitazone provided significantly greater reductions in A1c (0.4-0.7% differences) and other glycaemic endpoints than either monotherapy at the same doses. Combining sitagliptin with low-dose pioglitazone generally produced greater glycaemic improvements than higher doses of pioglitazone monotherapy (0.3-0.4% differences in A1c). Combination therapy was generally well tolerated; adverse events (AEs) of hypoglycaemia were reported with similar incidence (7.8-11.1%) in all treatment groups over the 54 weeks of study; oedema was reported in 0.5% of patients in the sitagliptin monotherapy group and 2.7-5.3% among pioglitazone-treated groups. Significant weight gain was observed in all combination-treated groups compared with the sitagliptin monotherapy group., Conclusions: Initial combination therapy with sitagliptin and pioglitazone provided better glycaemic control than either monotherapy and was generally well tolerated., (© 2013 John Wiley & Sons Ltd.)

Objective: The American Association of Clinical Endocrinologists and American College of Endocrinology (AACE/ACE) diabetes algorithm recommends a stratified approach to initial therapy to achieve a glycated hemoglobin (HbA1c) goal of ≤6.5% in patients with type 2 diabetes mellitus (T2DM) who have inadequate glycemic control. Data from a double-blind study in drug-naïve T2DM patients comparing initial monotherapy with metformin (MET) with initial dual therapy with a fixed-dose combination of sitagliptin and MET (SITA/MET FDC) was used to determine AACE/ACE HbA1c goal attainment in these treatment groups., Methods: A total of 1,250 patients (mean baseline HbA1c = 9.9%) were randomized 1:1 to SITA/MET FDC 50/500 mg twice daily (b.i.d.) or MET 500 mg b.i.d. for 18 weeks. SITA/MET FDC and MET were uptitrated over 4 weeks to 50/1,000 mg b.i.d. and 1,000 mg b.i.d., respectively., Results: At week 18, a higher percentage of patients receiving SITA/MET FDC had HbA1c levels ≤6.5% and <7% than those receiving MET alone within each of the 3 AACE/ACE HbA1c categories (6.5-7.5%, >7.5-9.0%, and >9.0%). Of patients with a baseline HbA1c >7.5-9.0% who initiated SITA/MET FDC, 48.6% achieved an HbA1c ≤6.5% at week 18 compared with 23.1% of patients who initiated MET monotherapy (P<.001). In patients with a baseline HbA1c >9.0%, 24.0% on SITA/MET FDC achieved an HbA1c ≤6.5% compared with 12.8% on MET alone (P<.001)., Conclusion: In T2DM patients with a baseline HbA1c >7.5-9.0%, substantially more achieved the HbA1c goal of ≤6.5% with initial dual therapy (SITA/MET FDC) than with initial monotherapy (MET), which is in agreement with the AACE/ACE diabetes algorithm.

Introduction: In a previous pooled analysis of 19 double-blind clinical studies conducted by Merck, which included data available as of July 2009 on 10,246 patients with type 2 diabetes (T2DM), treatment with sitagliptin was shown to be generally well tolerated compared with treatment with control agents. As the sitagliptin clinical development program continues, additional studies with sitagliptin have been completed. The present analysis updates the safety and tolerability assessment of sitagliptin by examining pooled data from 25 double-blind clinical studies., Methods: The present analysis included data from 14,611 patients in 25 studies with T2DM who received either sitagliptin 100 mg/day (n = 7,726; sitagliptin group) or a comparator agent (n = 6,885; non-exposed group). These studies represent all randomized, double-blind trials conducted by Merck 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 December 2011. These studies assessed sitagliptin, versus comparator agents, 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 metformin + pioglitazone or rosiglitazone). Patient-level data from each study were used to evaluate between-group differences in the exposure-adjusted incidence rates of adverse events (AEs)., Results: Overall incidence rates of AEs and drug-related AEs were higher in the non-exposed group compared with the sitagliptin group. Incidence rates of specific AEs were generally similar between the two groups, except for higher 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 of constipation in the sitagliptin group. Treatment with sitagliptin was not associated with an increased risk of major adverse cardiovascular events, malignancy, or pancreatitis., Conclusion: In this updated pooled safety analysis of data from 14,611 patients with T2DM, sitagliptin 100 mg/day was generally well tolerated in clinical trials of up to 2 years in duration.

Objective: Patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease have an increased risk of micro- and macrovascular disease, but limited options for antihyperglycemic therapy. We compared the efficacy and safety of sitagliptin with glipizide in patients with T2DM and moderate-to-severe chronic renal insufficiency and inadequate glycemic control., Research Design and Methods: Patients (n = 426) were randomized 1:1 to sitagliptin (50 mg every day [q.d.] for moderate renal insufficiency and 25 mg q.d. for severe renal insufficiency) or glipizide (2.5 mg q.d., adjusted based on glycemic control to a 10-mg twice a day maximum dose). Randomization was stratified by: 1) renal status (moderate or severe renal insufficiency); 2) history of cardiovascular disease; and 3) history of heart failure., Results: At week 54, treatment with sitagliptin was noninferior to treatment with glipizide in A1C change from baseline (-0.8 vs. -0.6%; between-group difference -0.11%; 95% CI -0.29 to 0.06) because the upper bound of the 95% CI was less than the prespecified noninferiority margin of 0.4%. There was a lower incidence of symptomatic hypoglycemia adverse events (AEs) with sitagliptin versus glipizide (6.2 and 17.0%, respectively; P = 0.001) and a decrease in body weight with sitagliptin (-0.6 kg) versus an increase (1.2 kg) with glipizide (difference, -1.8 kg; P < 0.001). The incidence of gastrointestinal AEs was low with both treatments., Conclusions: In patients with T2DM and chronic renal insufficiency, sitagliptin and glipizide provided similar A1C-lowering efficacy. Sitagliptin was generally well-tolerated, with a lower risk of hypoglycemia and weight loss versus weight gain, relative to glipizide.

Background: Treatment with oral antihyperglycemic agents has not been well characterized in patients with type 2 diabetes and end-stage renal disease (ESRD). The efficacy and safety of sitagliptin and glipizide monotherapy in patients with type 2 diabetes and ESRD on dialysis therapy were assessed in this study., Study Design: 54-week, randomized, double-blind, parallel-arm study., Setting & Participants: From 31 clinical sites in 12 countries, 129 patients 30 years or older with type 2 diabetes and ESRD who were on dialysis therapy and had a hemoglobin A1c (HbA1c) level of 7%-9% were randomly assigned 1:1 to treatment., Intervention: Monotherapy with sitagliptin, 25 mg daily or glipizide (initiated with 2.5 mg daily and titrated up to a potential maximum dose of 10 mg twice daily or down to avoid hypoglycemia)., Outcomes: Primary end points were 54-week change in HbA1c level from baseline and tolerability with sitagliptin. A secondary end point was the comparison of sitagliptin versus glipizide on the incidence of symptomatic hypoglycemia., Results: Of 129 patients randomly assigned, 64 were in the sitagliptin group (mean baseline age, 61 years; HbA1c, 7.9%) and 65 were in the glipizide group (mean baseline age, 59 years; HbA1c, 7.8%). After 54 weeks, the least squares mean change from baseline in HbA1c level was -0.72% (95% CI, -0.95% to -0.48%) with sitagliptin and -0.87% (95% CI, -1.11% to -0.63%) with glipizide, for a difference of 0.15% (95% CI, -0.18% to 0.49%). The incidences of symptomatic hypoglycemia and severe hypoglycemia were 6.3% versus 10.8% (between-group difference, -4.8% [95% CI, -15.7% to 5.6%]) and 0% versus 7.7% (between-group difference, -7.8% [95% CI, -17.1% to -1.9%]) in the sitagliptin and glipizide groups, respectively. Higher incidences (ie, 95% CI around between-treatment difference excluded 0) of cellulitis and headache were found with sitagliptin compared to glipizide (6.3% vs 0%, respectively, for both)., Limitations: Small sample size limits between-group comparisons., Conclusions: Treatment with sitagliptin or glipizide monotherapy was effective and well tolerated over 54 weeks in patients with type 2 diabetes and ESRD who were receiving dialysis., (Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Aims: To assess efficacy and safety of sitagliptin, a dipeptidyl peptidase-4 inhibitor, in combination therapy with metformin (≥1500 mg/day) and pioglitazone (≥30 mg/day) in patients with type 2 diabetes (T2DM) with inadequate glycemic control (hemoglobin A1c [HbA1c] ≥7.5% and ≤11%)., Methods: This placebo-controlled, double-blind study included 313 patients, mean baseline HbA1c=8.7%, who were randomized to receive sitagliptin 100 mg/day or placebo for 26 weeks., Results: The addition of sitagliptin led to significant (P<.001) mean changes from baseline relative to placebo in HbA1c (-0.7%), fasting plasma glucose (-1.0 mmol/L), and 2-h post-meal glucose (-2.2 mmol/L). In patients with baseline HbA1c ≥9.0%, mean changes from baseline in HbA1c were -1.6% and -0.8% for the sitagliptin and placebo groups, respectively (between-group difference -0.8%; P<.001). The incidences of reported adverse events were generally similar between the treatment groups. Incidences of symptomatic hypoglycemia were 7/157 [4.5%] and 6/156 [3.8%] in the sitagliptin and placebo groups, respectively (P=.786). Two patients, both in the placebo group, experienced an episode of hypoglycemia that required non-medical assistance., Conclusions: In this 26-week study, addition of sitagliptin to combination therapy with metformin and pioglitazone improved glycemic control and was generally well tolerated., (Copyright © 2013 Elsevier Inc. All rights reserved.)

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., Methods: The present study was a randomized double-blind placebo-controlled parallel-group 54-week study conducted at 41 sites across North and South America, Europe, and Asia in 278 patients with HbA1c ranging from ≥7.5% to ≤11.0% despite ongoing combination therapy with metformin (≥1500 mg/day) and rosiglitazone (≥4 mg/day). Patients were randomized (2:1) to receive sitagliptin 100 mg or placebo once daily. The main outcome measure was change from baseline in HbA1c at Week 18., Results: Mean baseline HbA1c was 8.8%. The mean placebo-adjusted change from baseline in HbA1c with sitagliptin treatment was -0.7% (P < 0.001) at Week 18 and -0.8% (P < 0.001) at Week 54. There were also significant (P < 0.001) reductions in 2-h post-meal glucose and fasting plasma glucose compared with placebo at Weeks 18 and 54. Significantly higher proportions of sitagliptin- than placebo-treated patients had HbA1c<7.0% at Weeks 18 (22% vs 9%; P = 0.003) and 54 (26% vs 14%; P = 0.015). Changes in body weight and the rates of adverse events overall, hypoglycemia, and gastrointestinal adverse events were similar in the sitagliptin and placebo groups during the 54-week study., Conclusions: In patients with T2D, the addition of sitagliptin for 54 weeks to ongoing therapy with metformin and rosiglitazone improved glycemic control and was generally well tolerated compared with placebo., (© 2012 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.)

Objective: To compare the incidence of cardiovascular events and mortality in patients with type 2 diabetes mellitus treated with sitagliptin or non-sitagliptin comparators., Methods: A post hoc assessment of cardiovascular safety in 14,611 patients was performed by pooling data from 25 double-blind studies, which randomised patients at baseline to sitagliptin 100 mg/day or a non-sitagliptin comparator (i.e., non-exposed). Included studies were limited to those at least 12 weeks in duration (range: 12 to 104 weeks). Patient-level data were used in this analysis of major adverse cardiovascular events (MACE) including ischaemic events and cardiovascular deaths. Analyses were performed in three cohorts: the entire 25-study cohort, the cohort from placebo-controlled portions of studies (n=19), and the cohort from studies comparing sitagliptin to a sulphonylurea (n=3)., Results: In the entire cohort analysis, 78 patients had at least 1 reported MACE-related event, with 40 in the sitagliptin group and 38 in the non-exposed group. The exposure-adjusted incidence rate was 0.65 per 100 patient-years in the sitagliptin group and 0.74 in the non-exposed group (incidence rate ratio = 0.83 [95% confidence interval (CI): 0.53, 1.30]). In the analysis comparing sitagliptin to placebo, the exposure-adjusted incidence rate was 0.80 per 100-patient-years with sitagliptin and 0.76 with placebo (incidence rate ratio = 1.01 [95% CI: 0.55, 1.86]). In the analysis comparing sitagliptin to sulphonylurea, the exposure-adjusted incidence rate was 0.00 per 100 patient-years with sitagliptin and 0.86 with sulphonylurea (incidence rate ratio = 0.00 [95% CI: 0.00, 0.31])., Conclusion: A pooled analysis of 25 randomised clinical trials does not indicate that treatment with sitagliptin increases cardiovascular risk in patients with type 2 diabetes mellitus. In a subanalysis, a higher rate of cardiovascular-related events was associated with sulphonylurea relative to sitagliptin.

Aim: To assess the 54-week efficacy of initial combination therapy with sitagliptin and pioglitazone, compared with pioglitazone monotherapy, and to assess safety in these groups during the 30 weeks after the dosage of pioglitazone was increased from 30 to 45 mg/day, in drug-naÏve patients with type 2 diabetes mellitus and inadequate glycaemic control [haemoglobin A1c (HbA1c) 8-12%]., Methods: Following a 24-week, randomized, double-blind, parallel-group study (Sitagliptin Protocol 064, Clinicaltrials.gov: NCT00397631; Yoon KH, Shockey GR, Teng R et al. Effect of initial combination therapy with sitagliptin, a dipeptidyl peptidase-4 inhibitor, and pioglitazone on glycaemic control and measures of beta-cell function in patients with type 2 diabetes. Int J Clin Pract 2011; 65: 154-164) in which patients were treated with the combination of sitagliptin 100 mg/day and pioglitazone 30 mg/day or monotherapy with pioglitazone 30 mg/day, patients entered a 30-week extension study. In the extension study, the pioglitazone dose was increased from 30 to 45 mg/day in both groups. Depending upon treatment allocation, patients took one tablet of sitagliptin 100 mg or matching placebo daily. Pioglitazone was administered in an open-label fashion as a single 45-mg tablet taken once daily. Patients not meeting specific glycaemic goals in the extension study were rescued with metformin therapy. Efficacy and safety results for the extension study excluded data after initiation of rescue therapy., Results: Of the 520 patients initially randomized, 446 completed the base study and, of these, 317 entered the extension. In this extension study cohort, the mean reductions from baseline in HbA1c and fasting plasma glucose (FPG) at the end of the base study (week 24) were -2.5% and -62.1 mg/dl with the combination of sitagliptin 100 mg and pioglitazone 30 mg versus -1.9% and -48.7 mg/dl with pioglitazone monotherapy. At the end of the extension study (week 54), the mean reduction in haemoglobin A1c (HbA1c) was -2.4% with the combination of sitagliptin 100 mg and pioglitazone 45 mg versus -1.9% with pioglitazone monotherapy [between-group difference (95% CI) = -0.5% (-0.8, -0.3)] and the mean reduction in FPG was -61.3 mg/dl versus -52.8 mg/dl, respectively [between-group difference (95% CI) = -8.5 mg/dl (-16.3, -0.7)]. Safety and tolerability of initial treatment with the combination of sitagliptin and pioglitazone and pioglitazone monotherapy were similar. As expected, increases in body weight from baseline were observed in both treatment groups at week 54: 4.8 and 4.1 kg in the combination and monotherapy groups, respectively [between-group difference (95% CI) = 0.7 kg (-0.7, 2.1)]., Conclusion: In this study, initial combination therapy with sitagliptin 100 mg and pioglitazone 30 mg increased to 45 mg after 24 weeks led to a substantial and durable incremental improvement in glycaemic control compared with initial treatment with pioglitazone monotherapy during a 54-week treatment period. Both initial combination therapy with sitagliptin and pioglitazone and pioglitazone monotherapy were generally well tolerated (Clinicaltrials.gov: NCT01028391)., (© 2012 Blackwell Publishing Ltd.)

Aims: To evaluate the efficacy and safety of initial therapy with a fixed-dose combination (FDC) of sitagliptin and metformin compared with pioglitazone in drug-naÏve patients with type 2 diabetes., Methods: After a 2-week single-blind placebo run-in period, patients with type 2 diabetes, HbA1c of 7.5-12% and not on antihyperglycaemic agent therapy were randomized in a double-blind manner to initial treatment with a FDC of sitagliptin/metformin 50/500 mg twice daily (N = 261) or pioglitazone 30 mg per day (N = 256). Sitagliptin/metformin and pioglitazone were up-titrated over 4 weeks to doses of 50/1000 mg twice daily and 45 mg per day, respectively. Both treatments were then continued for an additional 28 weeks., Results: From a mean baseline HbA1c of 8.9% in both groups, least squares (LS) mean changes in HbA1c at week 32 were -1.9 and -1.4% for sitagliptin/metformin and pioglitazone, respectively (between-group difference = -0.5%; p < 0.001). A greater proportion of patients had an HbA1c of <7% at week 32 with sitagliptin/metformin vs. pioglitazone (57% vs. 43%, p < 0.001). Compared with pioglitazone, sitagliptin/metformin treatment resulted in greater LS mean reductions in fasting plasma glucose (FPG) [-56.0 mg/dl (-3.11 mmol/l) vs. -44.0 mg/dl (-2.45 mmol/l), p < 0.001] and in 2-h post-meal glucose [-102.2 mg/dl (-5.68 mmol/l) vs. -82.0 mg/dl (-4.56 mmol/l), p < 0.001] at week 32. A substantially greater reduction in FPG [-40.5 mg/dl (-2.25 mmol/l) vs. -13.0 mg/dl (-0.72 mmol/l), p < 0.001] was observed at week 1 with sitagliptin/metformin vs. pioglitazone. A greater reduction in the fasting proinsulin/insulin ratio and a greater increase in homeostasis model assessment of β-cell function (HOMA-β) were observed with sitagliptin/metformin than with pioglitazone, while greater decreases in fasting insulin and HOMA of insulin resistance (HOMA-IR), and a greater increase in quantitative insulin sensitivity check index (QUICKI) were observed with pioglitazone than with sitagliptin/metformin. Both sitagliptin/metformin and pioglitazone were generally well tolerated. Sitagliptin/metformin led to weight loss (-1.4 kg), while pioglitazone led to weight gain (3.0 kg) (p < 0.001 for the between-group difference). Higher incidences of diarrhoea (15.3% vs. 4.3%, p < 0.001), nausea (4.6% vs. 1.2%, p = 0.02) and vomiting (1.9% vs. 0.0%, p = 0.026), and a lower incidence of oedema (1.1% vs. 7.0%, p < 0.001), were observed with sitagliptin/metformin vs. pioglitazone. The between-group difference in the incidence of hypoglycaemia did not reach statistical significance (8.4 and 4.3% with sitagliptin/metformin and pioglitazone, respectively; p = 0.055)., Conclusion: Compared with pioglitazone, initial therapy with a FDC of sitagliptin and metformin led to significantly greater improvement in glycaemic control as well as a higher incidence of prespecified gastrointestinal adverse events, a lower incidence of oedema and weight loss vs. weight gain., (© 2011 Blackwell Publishing Ltd.)

Aim: To examine the effect of sitagliptin and metformin, alone and in combination, on modelled parameters of β-cell function in patients with type 2 diabetes., Methods: The data used in the present analyses are from a 104-week study, which included a 24-week, placebo- and active controlled phase followed by a 30-week, active controlled, continuation phase and an additional 50-week, active controlled extension phase. Patients were randomised to one of six blinded treatments: sitagliptin 50 mg + metformin 1000 mg b.i.d., sitagliptin 50 mg + metformin 500 mg b.i.d., metformin 1000 mg b.i.d., metformin 500 mg b.i.d., sitagliptin 100 mg q.d. or placebo. Patients on placebo were switched in a blinded manner to metformin 1000 mg b.i.d. at week 24. Subsets of patients volunteered to undergo frequently sampled meal tolerance tests at baseline and at weeks 24, 54 and 104. β-cell responsivity was assessed with the C-peptide minimal model. The static component (Φ(s)) estimates the rate of insulin secretion related to above-basal glucose concentration. The dynamic component (Φ(d)) is related to the rate of change in glucose. The total index (Φ(total)) represents the overall response to a glycaemic stimulus and is calculated as a function of Φ(s) and Φ(d). Insulin sensitivity was estimated with the Matsuda index (ISI). The disposition index, which assesses insulin secretion relative to the prevailing insulin sensitivity, was calculated based on the Φ(total) and ISI., Results: At week 24, substantial reductions in postmeal glucose were observed with all active treatment groups relative to the placebo group. Φ(s), Φ(total) and the disposition index were significantly improved from baseline at week 24 with all active treatments relative to placebo. Generally larger effects were observed with the initial combination of sitagliptin and metformin relative to the monotherapy groups. When expressed as median percent change from baseline, Φ(s) increased from baseline by 137 and 177% in the low- and high-dose combination groups and by 85, 54, 73 and -9% in the high-dose metformin, low-dose metformin, sitagliptin monotherapy and placebo groups, respectively. At weeks 54 and 104, the combination treatment groups continued to demonstrate greater improvements in β-cell function relative to their respective monotherapy groups., Conclusions: After 24 weeks of therapy, relative to placebo, initial treatment with sitagliptin or metformin monotherapy improved β-cell function; moreover, initial combination therapy demonstrated larger improvements than the individual monotherapies. Improvements in β-cell function were found with treatments for up to 2 years., (© 2011 Blackwell Publishing Ltd.)

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 (HbA(1c)), 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 HbA(1c) was 7.8%. At week 24, HbA(1c) 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 HbA(1c) <8.0% (n = 132), ≥ 8.0% to <9.0% (n = 42), and ≥ 9.0% (n = 18), the placebo-adjusted reductions in HbA(1c) 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 (HbA(1c) ≥ 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.

This continuing education course for professionals involved in all areas of clinical trials integrates concepts related to the role of randomization in the scientific process. The course includes two interactive lecture and discussion sections and a workshop practicum. The first interactive lecture introduces basic clinical trial issues and statistical principles such as bias, blinding, randomization, control groups, and the importance of formulating clear and discriminating clinical and statistical hypotheses. It then focuses on the most commonly used clinical study designs and the corresponding patient randomization schemes. The second interactive lecture focuses on the implementation of randomization of patients and drug supply through allocation and component ID schedules. The workshop practicum, conducted in small groups, enables students to apply the lecture concepts to real clinical studies. Flexibility was built into the workshop practicum materials to allow the course content to be customized to specific audiences, and the interactive lecture sessions can be stretched to cover more advanced topics according to class interest and time availability., (Copyright © 2010 John Wiley & Sons, Ltd.)

Aim/hypothesis: To assess the safety and efficacy of initial combination therapy with sitagliptin and pioglitazone compared with pioglitazone monotherapy in drug-naïve patients with type 2 diabetes., Methods: A total of 520 patients were randomised to initial combination therapy with sitagliptin 100 mg q.d. and pioglitazone 30 mg q.d. or pioglitazone 30 mg q.d. monotherapy for 24 weeks., Results: Initial combination therapy with sitagliptin and pioglitazone led to a mean reduction from baseline in A1C of -2.4% compared with -1.5% for pioglitazone monotherapy (p<0.001). Mean reductions from baseline were greater in patients with a baseline A1C≥10% (-3.0% with combination therapy vs. -2.1% with pioglitazone monotherapy) compared with patients with a baseline A1C<10% (-2.0% with combination therapy vs. -1.1% with pioglitazone monotherapy). Sixty percent of patients in the combination therapy group vs. 28% in the pioglitazone monotherapy group had an A1C of <7% at week 24 (p<0.001). Fasting plasma glucose decreased by -63.0 mg/dl (-3.5 mmol/l) in the combination therapy group compared with -40.2 mg/dl (-2.2 mmol/l) for pioglitazone monotherapy (p<0.001), and 2-h post meal glucose decreased by -113.6 mg/dl (-6.3 mmol/l) with combination therapy compared with -68.9 mg/dl (-3.8 mmol/l) for pioglitazone monotherapy (p<0.001). Measures related to β-cell function also improved significantly with combination therapy compared with pioglitazone monotherapy. Combination therapy was generally well-tolerated compared with pioglitazone monotherapy, with similar incidences of hypoglycemia (1.1% and 0.8%, respectively), gastrointestinal adverse events (5.7% and 6.9%, respectively), and oedema (2.7% and 3.5%, respectively)., Conclusion/interpretation: Initial combination therapy with sitagliptin and pioglitazone substantially improved glycemic control and was generally well-tolerated compared with pioglitazone monotherapy., (© 2011 Blackwell Publishing Ltd.)

Recent case reports of acute pancreatitis in patients with type 2 diabetes (T2DM) treated with incretin-based therapies have triggered interest regarding the possibility of a mechanism-based association between pancreatitis and glucagon-like peptide-1 mimetics or dipeptidyl peptidase-4 (DPP-4) inhibitors. The objective of this review was to describe the controlled preclinical and clinical trial data regarding the incidence of pancreatitis with sitagliptin, the first DPP-4 inhibitor approved for use in patients with T2DM. Tissue samples from multiple animal species treated with sitagliptin for up to 2 years at plasma exposures substantially in excess of human exposure were evaluated to determine whether any potential gross or histomorphological changes suggestive of pancreatitis occurred. Sections were prepared by routine methods, stained with haematoxylin and eosin and examined microscopically. A pooled analysis of 19 controlled clinical trials, comprising 10,246 patients with T2DM treated for up to 2 years, was performed using patient-level data from each study for the evaluation of clinical and laboratory adverse events. Adverse events were encoded using the Medical Dictionary for Regulatory Activities (MedDRA) version 12.0 system. Incidences of adverse events were adjusted for patient exposure. Tissue samples from preclinical studies in multiple animal species did not reveal any evidence of treatment-related pancreatitis. The pooled analysis of controlled clinical trials revealed similar incidence rates of pancreatitis in patients treated with sitagliptin compared with those not treated with sitagliptin (0.08 events per 100 patient-years vs. 0.10 events per 100 patient-years, respectively). Preclinical and clinical trial data with sitagliptin to date do not indicate an increased risk of pancreatitis in patients with T2DM treated with sitagliptin.

Background: In 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., Methods: The 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., Results: Summary 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., Conclusions: In 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.

Background: Administration of two doses of hepatitis A (HA) vaccine to children > or = 2 years of age has been shown to be protective. The present study assessed whether HA vaccine can be administered as early as 6 months of age and whether it can be administered concomitantly with a hexavalent (HV) vaccine at this age., Methods: In an open label, randomized, parallel group study, the liquid HV vaccine (HEXAVAC) (diphtheria, tetanus, 2-component acellular pertussis, inactivated poliomyelitis vaccine, Haemophilus influenzae type b conjugated to tetanus protein and hepatitis B) was administered at 2, 4, 6, and 12 months of age to all children. HA vaccine (VAQTA) was given at 7 and 13 months in the separate administration group (Group 1) and at 6 and 12 months in the concomitant administration group (Group 2). Serum samples were obtained at 2, 7, 12, and 14 months in Group 1 and at 2, 7, 12, and 13 months in Group 2. The primary immunogenicity outcomes were the seroconversion rates for HA 1 month after the second dose of HA vaccine in initially seronegative subjects, and the seroconversion rates for each HV antigen 1 month after the third dose of the HV vaccine (both at 7 months of age)., Results: HA seropositivity rates 1 month after the second dose were 100% in both groups, regardless of initial serostatus. The responses to each HV antigen 1 month after the third dose were similar in both groups. The vaccines were generally well tolerated in both groups regardless of vaccine(s) administered., Conclusions: A schedule of two doses of HA vaccine, 6 months apart beginning at 6 months of age is highly immunogenic and well tolerated when administered alone or concomitantly with HV vaccine at 6 and 12 months of age.

Exposure to infection information is important for estimating vaccine efficacy, but it is difficult to collect and prone to missingness and mismeasurement. We discuss study designs that collect detailed exposure information from only a small subset of participants while collecting crude exposure information from all participants and treat estimation of vaccine efficacy in the missing data/measurement error framework. We extend the discordant partner design for HIV vaccine trials of Golm, Halloran, and Longini (1998, Statistics in Medicine, 17, 2335-2352.) to the more complex augmented trial design of Longini, Datta, and Halloran (1996, Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology 13, 440-447) and Datta, Halloran, and Longini (1998, Statistics in Medicine 17, 185-200). The model for this design includes three exposure covariates and both univariate and bivariate outcomes. We adapt recently developed semiparametric missing data methods of Reilly and Pepe (1995, Biometrika 82, 299 314), Carroll and Wand (1991, Journal of the Royal Statistical Society, Series B 53, 573-585), and Pepe and Fleming (1991, Journal of the American Statistical Association 86, 108-113) to the augmented vaccine trial design. We demonstrate with simulated HIV vaccine trial data the improvements in bias and efficiency when combining the different levels of exposure information to estimate vaccine efficacy for reducing both susceptibility and infectiousness. We show that the semiparametric methods estimate both efficacy parameters without bias when the good exposure information is either missing completely at random or missing at random. The pseudolikelihood method of Carroll and Wand (1991) and Pepe and Fleming (1991) was the more efficient of the two semiparametric methods.

Exposure to infection information is important for estimating vaccine efficacy, but it is difficult to collect and inherently prone to missingness and mismeasurement. It is, therefore, generally not feasible to collect good exposure information on all participants in a large vaccine trial. We discuss study designs that collect detailed exposure information for only a small subset of trial participants, while collecting crude exposure information on all participants, and treat estimation of vaccine efficacy in the missing data/measurement error framework. We demonstrate with the example of an HIV vaccine trial the improvements in bias and efficiency when we combine the different levels of exposure information to estimate vaccine efficacy for reducing both susceptibility and infectiousness. We compare the performance of recently developed semi-parametric missing data methods of Pepe and Fleming and Carroll and Wand, Robins, Hsieh and Newey, and Reilly and Pepe.