Association of Metformin With the Development of Age-Related Macular Degeneration

Importance

Age-related macular degeneration (AMD) is a leading cause of blindness with no treatment available for early stages. Retrospective studies have shown an association between metformin and reduced risk of AMD.

Objective

To investigate the association between metformin use and age-related macular degeneration (AMD).

Design, Setting, and Participants

The Diabetes Prevention Program Outcomes Study is a cross-sectional follow-up phase of a large multicenter randomized clinical trial, Diabetes Prevention Program (1996-2001), to investigate the association of treatment with metformin or an intensive lifestyle modification vs placebo with preventing the onset of type 2 diabetes in a population at high risk for developing diabetes. Participants with retinal imaging at a follow-up visit 16 years posttrial (2017-2019) were included. Analysis took place between October 2019 and May 2022.

Interventions

Participants were randomly distributed between 3 interventional arms: lifestyle, metformin, and placebo.

Main Outcomes and Measures

Prevalence of AMD in the treatment arms.

Results

Of 1592 participants, 514 (32.3%) were in the lifestyle arm, 549 (34.5%) were in the metformin arm, and 529 (33.2%) were in the placebo arm. All 3 arms were balanced for baseline characteristics including age (mean [SD] age at randomization, 49 [9] years), sex (1128 [71%] male), race and ethnicity (784 [49%] White), smoking habits, body mass index, and education level. AMD was identified in 479 participants (30.1%); 229 (14.4%) had early AMD, 218 (13.7%) had intermediate AMD, and 32 (2.0%) had advanced AMD. There was no significant difference in the presence of AMD between the 3 groups: 152 (29.6%) in the lifestyle arm, 165 (30.2%) in the metformin arm, and 162 (30.7%) in the placebo arm. There was also no difference in the distribution of early, intermediate, and advanced AMD between the intervention groups. Mean duration of metformin use was similar for those with and without AMD (mean [SD], 8.0 [9.3] vs 8.5 [9.3] years; P = .69). In the multivariate models, history of smoking was associated with increased risks of AMD (odds ratio, 1.30; 95% CI, 1.05-1.61; P = .02).

Conclusions and Relevance

These data suggest neither metformin nor lifestyle changes initiated for diabetes prevention were associated with the risk of any AMD, with similar results for AMD severity. Duration of metformin use was also not associated with AMD. This analysis does not address the association of metformin with incidence or progression of AMD.

Clinical endpoints and adaptive clinical trials in precirrhotic nonalcoholic steatohepatitis: Facilitating development approaches for an emerging epidemic

Due to the increasing prevalence of nonalcoholic steatohepatitis (NASH) and its associated health burden, there is a high need to develop therapeutic strategies for patients with this disease. Unfortunately, its long and asymptomatic natural history, the uncertainties about disease progression, the fact that most patients are undiagnosed, and the requirement for sequential liver biopsies create substantial challenges for clinical development. Adaptive design methods are increasingly used in clinical research as they provide the flexibility and efficiency for identifying potential signals of clinical benefit of the test treatment under investigation and make prompt preplanned adaptations without undermining the validity or integrity of the trial. Given the high unmet medical need and the lack of validated surrogate endpoints in NASH, the use of adaptive design methods appears reasonable. Furthermore, due to the limited number of patients willing to have multiple liver biopsies and the need for long‐term exposure to assess an impact in outcomes, a continuous seamless adaptive design may reduce the overall sample size while allowing patients to continue after each one of the phases. Here, we review strategic frameworks that include potential surrogate endpoints as well as statistical and logistical approaches that could be considered for applying adaptive designs to clinical trials in NASH with the goal of facilitating drug development for this growing medical need. (Hepatology Communications 2017;1:577–585)

Structure of proof of concept studies that precede a nonalcoholic steatohepatitis development program

Surrogate endpoints for clinical proof of concept (POC) trials in nonalcoholic steatohepatitis (NASH) are based upon expert pathological review of liver biopsies. During early development, these long‐term POC studies (≥48 weeks) add cost and time to the “Go/No Go” decision process. However, it is possible to conduct short‐term noninvasive POC studies utilizing biomarkers and magnetic resonance imaging. Here, we discuss the use of shorter noninvasive POC studies relative to biopsy‐driven studies for drug development in NASH.

A randomized clinical trial evaluating the safety and efficacy of sitagliptin added to the combination of sulfonylurea and metformin in patients with type 2 diabetes mellitus and inadequate glycemic control

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.

Sitagliptin improves glycaemic excursion after a meal or after an oral glucose load in Japanese subjects with impaired glucose tolerance

AIMS

To evaluate the efficacy and tolerability of sitagliptin in subjects with impaired glucose tolerance (IGT).

METHODS

In a double-blind, parallel-group study, 242 Japanese subjects with IGT, determined by a 75-g oral glucose tolerance test (OGTT) at week -1, were randomized (1 : 1 : 1) to placebo (n = 83), sitagliptin 25 mg (n = 82) or 50 mg (n = 77) once daily for 8 weeks. Glycaemic variables were assessed using another OGTT at week 7 and meal tolerance tests (MTTs) at weeks 0 and 8. Primary and secondary endpoints were percent change from baseline in glucose total area under the curve 0-2 h (AUC(0 -2 h)) during the MTT and OGTT, respectively.

RESULTS

Least squares mean percent change from baseline in glucose AUC(0 -2 h) during the MTT were -2.4, -9.5 and -11.5%, and during the OGTT were -3.7, -21.4 and -20.1% with placebo, sitagliptin 25 mg once daily, and 50 mg once daily, respectively (p < 0.001 for either sitagliptin dose vs placebo in both tests). Sitagliptin treatment enhanced early insulin response during the OGTT and decreased total insulin response, assessed as the total AUC(0 -2 h) during the MTT. Sitagliptin treatment also suppressed glucagon response during the MTT. The incidence of adverse events, including hypoglycaemia, was low and generally similar in all treatment groups.

CONCLUSIONS

Treatment with sitagliptin significantly reduced glucose excursions during both an MTT and an OGTT; this effect was associated with an increase in early insulin secretion after oral glucose loading as well as a blunted glucagon response during an MTT. Sitagliptin was generally well tolerated in subjects with IGT.

Safety and Efficacy of Omarigliptin (MK-3102), a Novel Once-Weekly DPP-4 Inhibitor for the Treatment of Patients With Type 2 Diabetes

OBJECTIVE

This study was conducted to determine the optimal dose of omarigliptin, a once-weekly (q.w.) dipeptidyl peptidase IV (DPP-4) inhibitor, for the treatment of patients with type 2 diabetes and evaluate the long-term safety of that dose.

RESEARCH DESIGN AND METHODS

In a multicenter, double-blind, 12-week, dose-range finding study, 685 oral antihyperglycemic agent-naïve or washed-out subjects with type 2 diabetes were randomized to one of five once-weekly doses of omarigliptin (0.25 mg, 1 mg, 3 mg, 10 mg, or 25 mg) or placebo. The primary efficacy end point was change from baseline in HbA1c, and secondary end points were 2-h postmeal glucose (PMG) and fasting plasma glucose (FPG). Analysis included all patients who received at least one dose of the study medication. Subjects who completed the base study were eligible to enter a 66-week extension study.

RESULTS

Once-weekly treatment for 12 weeks with omarigliptin provided dose-related reductions in HbA1c, 2-h PMG, and FPG. At week 12, the omarigliptin 25-mg dose provided the greatest glycemic efficacy. The placebo-adjusted least-squares mean reductions from baseline in HbA1c, 2-h PMG, and FPG were -0.72% (-7.8 mmol/mol), -2.5, and -1.3 mmol/L, respectively (all P < 0.001). The incidence of adverse events was similar across dose groups, with a low incidence of symptomatic hypoglycemia and no effect on body weight. Omarigliptin was generally well-tolerated throughout the base and extension studies.

CONCLUSIONS

Omarigliptin 25 mg q.w., compared with placebo, provided significant glucose lowering and was generally well tolerated for up to 78 weeks in patients with type 2 diabetes.

A comparison of glycaemic effects of sitagliptin and sulfonylureas in elderly patients with type 2 diabetes mellitus

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.

Long-term efficacy of sitagliptin as either monotherapy or add-on therapy to metformin: improvement in glycemic control over 2 years in patients with type 2 diabetes

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.

Comparison of treatment with sitagliptin or sulfonylurea in patients with type 2 diabetes mellitus and mild renal impairment: a post hoc analysis of clinical trials

INTRODUCTION

Impaired renal function is a major complication of type 2 diabetes mellitus (T2DM). Mild renal impairment is present in 38% of patients with T2DM and may impact choice of antihyperglycemic agent. Sulfonylureas and dipeptidyl peptidase-4 (DPP-4) inhibitors are commonly used to treat hyperglycemia in patients with T2DM and renal impairment. Although in general sulfonylurea use is associated with an increased risk of hypoglycemia and weight gain, while DPP-4 inhibitor use is associated with a low risk of hypoglycemia, and is weight neutral, the relative efficacy and tolerability of these agents in patients with mild renal impairment has not been evaluated.

METHODS

In a post hoc analysis, data from 1,211 subjects with T2DM and mild renal impairment (estimated glomerular filtration rates of 60 to <90 mL/min/1.73 m(2)), who completed 25 or 30 weeks of one of three double-blind clinical trials comparing the DPP-4 inhibitor sitagliptin 100 mg/day with sulfonylureas in titrated doses, were pooled. The analysis compared change from baseline in glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), body weight, incidence of symptomatic hypoglycemia and the percentages of subjects meeting a composite endpoint of HbA1c decrease >0.5% without symptomatic hypoglycemia or body weight gain between sitagliptin and sulfonylurea treatment groups.

RESULTS

HbA1c and FPG decreased similarly with sitagliptin or sulfonylurea. A lower incidence of hypoglycemia was observed with sitagliptin. Body weight decreased with sitagliptin but increased with sulfonylurea. A greater percentage of subjects treated with sitagliptin (41.1%) than treated with sulfonylurea (16.9%) achieved the composite endpoint of >0.5% HbA1c reduction with no symptomatic hypoglycemia or body weight gain.

CONCLUSION

In this analysis of subjects with T2DM and mild renal impairment, treatment with sitagliptin provided glycemic efficacy similar to sulfonylurea, with less hypoglycemia and with body weight loss compared to body weight gain seen with sulfonylurea.

TRIAL REGISTRATIONS

ClinicalTrials.gov #NCT00482079, #NCT00094770, #NCT00701090.

Safety of sitagliptin in elderly patients with type 2 diabetes: a pooled analysis of 25 clinical studies

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.

Efficacy and safety of initial combination treatment with sitagliptin and pioglitazone--a factorial study

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.

Sitagliptin and pioglitazone provide complementary effects on postprandial glucose and pancreatic islet cell function

AIMS

The effects of sitagliptin and pioglitazone, alone and in combination, on α- and β-cell function were assessed in patients with type 2 diabetes.

METHODS

Following a 6-week diet/exercise period, 211 patients with HbA1c of 6.5-9.0% and fasting plasma glucose of 7.2-14.4 mmol/l were randomized (1 :1 :1 : 1) to sitagliptin, pioglitazone, sitagliptin + pioglitazone or placebo. At baseline and after 12 weeks, patients were given a mixed meal followed by frequent blood sampling for measurements of glucose, insulin, C-peptide and glucagon.

RESULTS

After 12 weeks, 5-h glucose total area under the curve (AUC) decreased in all active treatments versus placebo; reduction with sitagliptin + pioglitazone was greater versus either monotherapy. The 5-h insulin total AUC increased with sitagliptin versus all other treatments and increased with sitagliptin + pioglitazone versus pioglitazone. The 3-h glucagon AUC decreased with sitagliptin versus placebo and decreased with sitagliptin + pioglitazone versus pioglitazone or placebo. Φ(s), a measure of dynamic β-cell responsiveness to above-basal glucose concentrations, increased with either monotherapy versus placebo and increased with sitagliptin + pioglitazone versus either monotherapy. The insulin sensitivity index (ISI), a composite index of insulin sensitivity, improved with pioglitazone and sitagliptin + pioglitazone versus placebo. The disposition index, a measure of the relationship between β-cell function and insulin sensitivity, improved with all active treatments versus placebo.

CONCLUSIONS

Sitagliptin and pioglitazone enhanced β-cell function (increasing postmeal Φ(s)), and sitagliptin improved α-cell function (decreasing postmeal glucagon) after 12 weeks in patients with type 2 diabetes. Through these complementary mechanisms of action, the combination of sitagliptin and pioglitazone reduced postmeal glucose more than either treatment alone.

Safety and tolerability of sitagliptin in type 2 diabetes: pooled analysis of 25 clinical studies

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.

Efficacy and safety of sitagliptin versus glipizide in patients with type 2 diabetes and moderate-to-severe chronic renal insufficiency

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.

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.

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.

Efficacy and safety of sitagliptin added to ongoing metformin and pioglitazone combination therapy in a randomized, placebo-controlled, 26-week trial in patients with type 2 diabetes

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.

Efficacy and safety of sitagliptin in patients with type 2 diabetes and ESRD receiving dialysis: a 54-week randomized trial

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.

Cardiovascular safety of sitagliptin in patients with type 2 diabetes mellitus: a pooled analysis

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.

Impact of diabetes duration and chronic pancreatitis on the association between type 2 diabetes and pancreatic cancer risk

AIM

To examine the impact of diabetes duration, chronic pancreatitis and other factors on pancreatic cancer risk.

METHODS

This retrospective cohort study using the UK General Practice Research Database compared pancreatic cancer incidence and risk in patients with type 2 diabetes mellitus (T2DM) versus patients without diabetes. Multivariate Cox regression adjusting for age, sex, history of chronic pancreatitis, gallbladder disease, obesity, smoking and alcohol use and Charlson comorbidity index was used to estimate hazard ratio (HR) [95% confidence interval, CI]. Analyses were repeated using various time windows for diabetes duration.

RESULTS

A total of 1903 incident pancreatic cancers were identified, 436 in patients with T2DM (78.76 per 100 000 person-years [95% CI: 71.54, 86.51]) and 1467 in patients without diabetes (11.46 per 100 000 person-years [10.88, 12.06]). Pancreatic cancer risk was significant for T2DM (adjusted HR 1.80 [1.52, 2.14]), increasing age, history of chronic pancreatitis and tobacco use. For patients with chronic pancreatitis and T2DM, the adjusted HR was 12.12 [6.02, 24.40]. Incidence was highest in patients with ≥5 year duration of T2DM. In patient populations with duration of T2DM ranging from ≥1 to ≥5 years, adjusted HRs remained significant but point estimates attenuated slightly with longer duration of T2DM.

CONCLUSIONS

Patients with T2DM had an 80% increased risk of pancreatic cancer versus patients without diabetes. Patients with T2DM and chronic pancreatitis were 12 times more likely to develop pancreatic cancer.

The addition of sitagliptin to ongoing metformin therapy significantly improves glycemic control in Chinese patients with type 2 diabetes

BACKGROUND

  The present study was conducted to evaluate the efficacy, safety and tolerability of sitagliptin added to ongoing metformin therapy in Chinese patients with type 2 diabetes (T2DM) who failed to achieve adequate glycemic control with metformin monotherapy.

METHODS

  After a metformin titration/stabilization period and a 2-week, single-blind, placebo run-in period, 395 Chinese patients with T2DM aged 25-77 years (baseline HbA1c 8.5%) were randomized (1:1) to double-blind placebo or sitagliptin 100 mg q.d. added to ongoing open-label metformin (1000 or 1700 mg/day) for 24 weeks.

RESULTS

  Significant (P < 0.001) changes from baseline in HbA1c (-0.9%), fasting plasma glucose (-1.2 mmol/L), and 2-h post-meal plasma glucose (-1.9 mmol/L) were seen with sitagliptin compared with placebo. There were no significant differences between sitagliptin and placebo in the incidence of hypoglycemia or gastrointestinal adverse events. A small decrease from baseline body weight was observed in the placebo group compared with no change in the sitagliptin group (between-group difference 0.5kg; P=0.018).

CONCLUSIONS

  The addition of sitagliptin 100 mg to ongoing metformin therapy significantly improved glycemic control and was generally well tolerated in Chinese patients with T2DM who had inadequate glycemic control on metformin alone.

Lower risk of hypoglycemia with sitagliptin compared to glipizide when either is added to metformin therapy: a pre-specified analysis adjusting for the most recently measured HbA(1c) value

BACKGROUND

In a previously-published study, adding sitagliptin or glipizide to ongoing metformin therapy provided similar HbA(1c) improvement (both groups, -0.7%) after 52 weeks in patients with type 2 diabetes (T2DM). Significantly fewer patients experienced symptomatic hypoglycemia with sitagliptin (5% of 588 patients) compared to glipizide (32% of 584 patients). Glycemic efficacy and patient characteristics may influence hypoglycemic events. The present analysis evaluated the risk of hypoglycemia with sitagliptin or glipizide after adjusting for the most recently measured HbA(1c) value.

METHODS

Data for this analysis were from the aforementioned 52-week, randomized, double-blind, active-controlled study. The primary endpoint was confirmed hypoglycemia (i.e., symptomatic hypoglycemia confirmed with a concurrent fingerstick glucose ≤70 mg/dL [3.9 mmol/L]); the secondary endpoint was severe hypoglycemia (requiring medical or non-medical assistance or symptoms of neuroglycopenia). Complementary log-log regression random effects models with terms for treatment, most recently measured HbA(1c) value, time (i.e., days since randomization), gender, and age (< or ≥65 years) were used to assess adjusted subject-specific treatment effects.

RESULTS

Over the full range of HbA(1c) levels and follow-up time, the risk of confirmed hypoglycemic events was lower with sitagliptin compared with glipizide (31 vs. 448 events; adjusted hazard ratio [HR] = 0.05 [95% CI: 0.03, 0.09], p < 0.001). The risk was also lower with sitagliptin in the younger (HR = 0.06 [95% CI: 0.03, 0.12], p < 0.001) and older (HR = 0.02 [0.01, 0.08], p < 0.001) age groups compared with glipizide. For severe hypoglycemia events (2 vs. 22), the risk was lower with sitagliptin (HR = 0.08 [95% CI: 0.01, 0.47]; p = 0.005).

LIMITATIONS

The actual time between the HbA(1c) measurement and the hypoglycemic event was variable and not controlled for in the analysis.

CONCLUSION

In pre-specified analyses adjusting for the most recently measured HbA(1c) value, there was a substantial reduction in risk for confirmed hypoglycemia with sitagliptin compared to glipizide when added to ongoing metformin therapy in patients with T2DM. The risk of confirmed hypoglycemia was very low in younger and older patients treated with sitagliptin.

Efficacy and safety of initial combination therapy with sitagliptin and pioglitazone in patients with type 2 diabetes: a 54-week study

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).