Double-blind, randomized clinical trial comparing the efficacy and safety of continuing or discontinuing the dipeptidyl peptidase-4 inhibitor sitagliptin when initiating insulin glargine therapy in patients with type 2 diabetes: The CompoSIT-I Study

Observational studies to emulate randomized trials: Some real-world barriers

The randomized controlled trial (RCT) forms the basis for drug approval by regulatory agencies. Observational studies using existing data from healthcare databases now also provide real-world evidence (RWE) in regulatory decision-making. Several initiatives are assessing the value of RWE by conducting observational studies that emulate published RCTs. While many RCTs are straightforward to emulate, others are challenging. We describe three RCT design aspects that pose challenges for observational studies. First are trials that enrol already treated subjects who must discontinue these treatments at the time of randomization, which can distort the comparison with observational studies. Second is the inclusion of a run-in phase, especially to exclude non-compliant subjects from the trial. Third are trials that evaluate the effect of weaning off treatment. In conclusion, future randomized trials that aim to be emulated by observational studies could consider study designs that allow emulation and thus provide valid and complementary RWE.

Impact of concomitant oral glucose-lowering medications on the success of basal insulin titration in insulin-naïve patients with type 2 diabetes: a systematic analysis

Basal insulin treatment for type 2 diabetes is usually initiated on a background of oral glucose-lowering medications (OGLM). We wanted to examine the influence of various OGLMs on fasting plasma glucose (FPG) and hemoglobin A_1c (HbA_1c) values achieved after titration. A PubMed literature search retrieved 42 publications (clinical trials introducing basal insulin in 17 433 insulin-naïve patients with type 2 diabetes on a defined background of OGLM) and reporting FPG, HbA_1c, target achievement, hypoglycemic events, and insulin doses. 60 individual study arms were grouped by OGLM (combinations) allowed during the titration process: (a) metformin only; (b) sulfonylureas only; (c) metformin and sulfonylureas; or (d) metformin and dipeptidyl peptidase-4 (DPP-4) inhibitors. For all OGLM categories, weighted means and SD were calculated for baseline and end-of-treatment FPG, HbA_1c, target achievement, incidence of hypoglycemic events, and insulin doses. Primary end point was a difference in FPG after titration between OGLM categories. Statistics: analysis of variance and post hoc comparisons. Sulfonylureas, alone or in combination with metformin, impair the titration of basal insulin (insulin doses 30%-40% lower, more hypoglycemic episodes), thus leading to poorer final glycemic control (p<0.05 for FPG and HbA_1c after titration). Conversely, adding a DPP-4 inhibitor to metformin is superior to metformin alone (p<0.05 for FPG and HbA_1c achieved) in patients with type 2 diabetes initiating basal insulin therapy. In conclusion, OGLM are a major determinant of the success of basal insulin therapy. Sulfonylureas impair, while DPP-4 inhibitors (added to metformin) may facilitate the achievement of ambitious fasting glucose targets. PROSPERO registration number CRD42019134821.

Sensitivity analyses in longitudinal clinical trials via distributional imputation

Missing data is inevitable in longitudinal clinical trials. Conventionally, the missing at random assumption is assumed to handle missingness, which however is unverifiable empirically. Thus, sensitivity analyses are critically important to assess the robustness of the study conclusions against untestable assumptions. Toward this end, regulatory agencies and the pharmaceutical industry use sensitivity models such as return-to-baseline, control-based, and washout imputation, following the ICH E9(R1) guidance. Multiple imputation is popular in sensitivity analyses; however, it may be inefficient and result in an unsatisfying interval estimation by Rubin's combining rule. We propose distributional imputation in sensitivity analysis, which imputes each missing value by samples from its target imputation model given the observed data. Drawn on the idea of Monte Carlo integration, the distributional imputation estimator solves the mean estimating equations of the imputed dataset. It is fully efficient with theoretical guarantees. Moreover, we propose weighted bootstrap to obtain a consistent variance estimator, taking into account the variabilities due to model parameter estimation and target parameter estimation. The superiority of the distributional imputation framework is validated in the simulation study and an antidepressant longitudinal clinical trial.

Dipeptidyl peptidase-4 inhibitor and insulin combination treatment in type 2 diabetes and chronic kidney disease: A meta-analysis

AIMS/INTRODUCTION

The union of dipeptidyl peptidase-4 inhibitors and insulin in patients with type 2 diabetes and chronic kidney disease provides satisfactory glucose management without increasing adverse events (AEs). This research appraised the therapeutic effect and safety of combination therapy in patients with type 2 diabetes and chronic kidney disease.

MATERIALS AND METHODS

We carried out a meta-analysis of randomized controlled trials to analyze AEs, hypoglycemia, serious AEs, severe hypoglycemia, estimated glomerular filtration rate, fasting plasma glucose, glycated hemoglobin, insulin dose, low-density lipoprotein cholesterol, uric acid and weight between combination treatment groups and control groups by searching the Cochrane Library, Excerpta Medica Database (Embase), PubMed and Web of Science databanks until October 2020.

RESULTS

Five studies (6 trials, 1,278 participants) met the inclusion criteria. The evidence quality ranged from moderate to high. Glycated hemoglobin (standardized mean difference -0.29, 95% confidence interval -0.44 to -0.14) and insulin dose (standardized mean difference -0.16, 95% confidence interval -0.29 to -0.02) were obviously smaller in the combination cure patients than in the control patients. Compared with the control groups, combination treatment did not increase AEs, hypoglycemia, serious AEs or severe hypoglycemia.

CONCLUSIONS

This study showed the effectiveness and safety of dipeptidyl peptidase-4 inhibitors bonded with insulin in patients with type 2 diabetes and chronic kidney disease, but the protective actions of this cure on kidney and cardiovascular outcomes, as well as the functions of other dipeptidyl peptidase-4 inhibitors, need to be affirmed by more good-quality randomized controlled trials.

A randomized clinical trial of the efficacy and safety of sitagliptin as initial oral therapy in youth with type 2 diabetes

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).

Impact of the Fasting Plasma Glucose Titration Target on the Success of Basal Insulin Titration in Insulin-Naïve Patients with Type 2 Diabetes: A Systematic Analysis

BACKGROUND/AIM

We aimed to examine beneficial and adverse outcomes of basal insulin titration performed with different fasting plasma glucose (FPG) titration targets (TT).

METHODS

A PubMed literature search retrieved 43 reported prospective clinical trials introducing basal insulin in 17643 insulin-naïve patients with type 2 diabetes reporting fasting plasma glucose (FPG), HbA_1c, target achievement, hypoglycemic events, and insulin doses. 61 individual study arms were grouped by fasting plasma glucose titration target (TT; 1: ≤5.0 mmol/l/90 mg/dl; 2: 5.01-5.6 mmol/l/90-100 mg/dl; and 3: ≥5.61 mmol/l/101 mg/dl). Weighted means and their standard deviations were calculated for baseline and end-of-treatment FPG (primary endpoint), HbA_1c, target achievement, hypoglycemic events, insulin doses, and body weight gain and compared over a duration of 31 ± 10 weeks.

RESULTS

Achieved FPG and HbA_1c at the end of the study were significantly lower (by up to 0.8 mmol/l or 0.23%, respectively) with more ambitious TTs (p < 0.0001), leading to better HbA_1c target achievement with more ambitious TTs (by up to 14.6% for HbA_1c ≤ 6.5%), without increasing the risk for hypoglycemic episodes.

CONCLUSIONS

Aiming for a lower FPG TT improves glycemic control without increasing the risk for hypoglycemia.

Anagliptin alleviates lipopolysaccharide-induced inflammation, apoptosis and endothelial dysfunction of lung microvascular endothelial cells

It has been reported that dipeptidyl peptidase-4 (DPP4) inhibition protects against acute lung injury (ALI). Anagliptin is a novel selective inhibitor of DPP4 but its role in ALI has not been studied. The present study aimed to investigate the effects of anagliptin on lipopolysaccharide (LPS)-induced human pulmonary microvascular endothelial cell (HPMVEC) injury, as well as its underlying mechanism. HPMVECs were exposed to LPS in the presence or absence of anagliptin co-treatment. MTT assay was used to evaluate cell viability and nitric oxide (NO) production was detected using a commercial kit. DPP4 and pro-inflammatory cytokine expression levels, apoptosis and migration were assessed via reverse transcription-quantitative PCR, western blotting, TUNEL staining and wound healing assay, respectively. Western blot analysis was performed to assess expression levels of proteins involved in NF-κB signaling, cell apoptosis and migration, as well as high mobility group box 1 (HMGB1)/receptor for advanced glycation end products (RAGE). LPS decreased cell viability and NO production, but elevated expression of DPP4 in HPMVECs. LPS promoted pro-inflammatory cytokine expression, NF-κB activation and cell apoptosis, but inhibited cell migration and phosphorylated-AKT/endothelial NO synthase expression. Anagliptin co-treatment significantly restored all of these effects. Mechanistically, the upregulation of HMGB1/RAGE expression induced by LPS was markedly blocked by anagliptin. In conclusion, anagliptin alleviated inflammation, apoptosis and endothelial dysfunction in LPS-induced HPMVECs via modulating HMGB1/RAGE expression. These data provide a basis for use of anagliptin in ALI treatment.

A randomized, placebo-controlled study to evaluate the efficacy and safety of adding omarigliptin to insulin therapy in Japanese patients with type 2 diabetes and inadequate glycaemic control

AIM

To evaluate the efficacy and safety of adding the once-weekly oral dipeptidyl peptidase-4 inhibitor omarigliptin to treatment of Japanese patients with type 2 diabetes and inadequate glycaemic control on insulin monotherapy.

MATERIALS AND METHODS

In a 52-week clinical trial, Japanese patients on insulin monotherapy were randomized to once-weekly omarigliptin 25 mg (N = 123) or placebo (N = 61) for a 16-week, double-blind, placebo-controlled period. After Week 16, patients continued or switched to omarigliptin for a 36-week open-label period.

RESULTS

From a mean baseline of approximately 8.8%, the Week 16 least squares mean changes in HbA1c were -0.61% (omarigliptin) and 0.29% (placebo); the between-group difference was -0.90% (p < .001). At Week 52, the mean change from baseline in HbA1c was -0.57% in both the group on omarigliptin for 52 weeks and the group on omarigliptin for 36 weeks (switched from placebo at Week 16). During the first 16 weeks of treatment, the incidences of adverse events (AEs), serious AEs, drug-related AEs and discontinuation from trial medication because of an AE were similar in both groups. A slight increase in incidence of symptomatic hypoglycaemia was observed in the omarigliptin group (n = 13 [10.6%]) compared with placebo (n = 4 [6.6%]). No severe hypoglycaemia was reported during the study. No new safety signals emerged with treatment beyond Week 16 through Week 52.

CONCLUSION

The addition of once-weekly omarigliptin to insulin therapy for up to 52 weeks was generally well tolerated and provided clinically meaningful improvement in glycaemic control throughout the trial period. ClinicalTrials.gov: NCT02906709.

Budget Impact of Oral Semaglutide Intensification versus Sitagliptin among US Patients with Type 2 Diabetes Mellitus Uncontrolled with Metformin

BACKGROUND

Oral semaglutide was approved in 2019 for blood glucose control in patients with type 2 diabetes mellitus (T2DM) and was the first oral glucagon-like peptide 1 receptor agonist (GLP-1 RA). T2DM is associated with substantial healthcare expenditures in the US, so the cost of a new intervention should be weighed against clinical benefits.

OBJECTIVE

This study evaluated the budget impact of a treatment pathway with oral semaglutide 14 mg daily versus oral sitagliptin 100 mg daily among patients not achieving target glycated hemoglobin (HbA1c) level despite treatment with metformin.

METHODS

This study used the validated IQVIA™ CORE Diabetes Model to simulate the treatment impact of oral semaglutide 14 mg and sitagliptin 100 mg over a 5-year time horizon from a US healthcare sector (payer) perspective. Trial data (PIONEER 3) informed cohort characteristics and treatment effects, and literature sources informed event costs. Population and market share data were from the literature and data on file. The analysis evaluated the estimated budget impact of oral semaglutide 14 mg use for patients currently using sitagliptin 100 mg considering both direct medical and treatment costs to understand the impact on total cost of care, given underlying treatment performance and impact on avoidable events.

RESULTS

In a hypothetical plan of 1 million lives, an estimated 1993 patients were treated with sitagliptin 100 mg in the target population. Following these patients over 5 years, the incremental direct medical and treatment costs of a patient using oral semaglutide 14 mg versus sitagliptin 100 mg was $US16,562, a 70.7% increase (year 2019 values). A hypothetical payer would spend an additional $US3,300,143 (7.1%) over 5 years for every 10% of market share that oral semaglutide 14 mg takes away from sitagliptin 100 mg. Univariate and scenario analyses with alternate inputs and assumptions demonstrated consistent results.

CONCLUSIONS

Use of oral semaglutide 14 mg in patients currently receiving sitagliptin 100 mg substantially increases the budget impact for patients with T2DM whose blood glucose level is not controlled with metformin over a 5-year time horizon for US healthcare payers.

Efficient Multiple Imputation for Sensitivity Analysis of Recurrent Events Data with Informative Censoring

Missing data are commonly encountered in clinical trials due to dropout or nonadherence to study procedures. In trials in which recurrent events are of interest, the observed count can be an undercount of the events if a patient drops out before the end of the study. In many applications, the data are not necessarily missing at random and it is often not possible to test the missing at random assumption. Consequently, it is critical to conduct sensitivity analysis. We develop a control-based multiple imputation method for recurrent events data, where patients who drop out of the study are assumed to have a similar response profile to those in the control group after dropping out. Specifically, we consider the copy reference approach and the jump to reference approach. We model the recurrent event data using a semiparametric proportional intensity frailty model with the baseline hazard function completely unspecified. We develop nonparametric maximum likelihood estimation and inference procedures. We then impute the missing data based on the large sample distribution of the resulting estimators. The variance estimation is corrected by a bootstrap procedure. Simulation studies demonstrate the proposed method performs well in practical settings. We provide applications to two clinical trials.

Effect of adding vildagliptin to insulin in haemodialysed patients with type 2 diabetes: The VILDDIAL study, a randomized, multicentre, prospective study

AIM

To evaluate the effect of adding the dipeptidyl-peptidase-4 inhibitor vildagliptin to insulin on the glycaemic control of patients with type 2 diabetes undergoing haemodialysis.

METHODS

Overall, 65 insulin-treated patients with type 2 diabetes undergoing haemodialysis (HbA1c: 7.3% ± 1.1%; age: 70.5 ± 8.5 years) were randomized (1:1) either to receive vildagliptin 50 mg/day in addition to insulin (vildagliptin-insulin group) or to pursue their usual insulin regimen (insulin-only group). Continuous glucose monitoring (CGM) was performed for 48 ± 6 hours at baseline and at week 12. The primary study endpoint was change from baseline in mean interstitial glucose using CGM. The secondary endpoints included other CGM variables and glucose control markers.

RESULTS

After 12 weeks, a greater reduction in mean CGM glucose from baseline was observed in the vildagliptin-insulin group compared with the insulin-only group, although the between-treatment difference was not statistically significant (mean difference [CI 95%]: -0.96 mmol/L [-2.09; 0.18] vs. -0.29 mmol/L [-1.29; 0.76], P = 0.32). However, a significant decrease from baseline in HbA1c, glycated albumin and insulin daily doses was observed in the vildagliptin-insulin group versus the insulin-only group (-0.6% [-1.19; -0.1], P < 0.01), in the vildagliptin-insulin group versus no change in the insulin-only group (-130.6 μmol/L [-271; 10.7] vs. +36.2 μmol/L [-164.4; 236.9], P = 0.04 and - 5.9 IU/day [-1.8; 7.1] vs. +1.1 IU/day [-14.5; 16.6], P = 0.01, respectively). There was no significant difference in the percentage of time spent in hypoglycaemia using CGM, occurrence of severe hypoglycaemia or number of adverse events.

CONCLUSION

In this study, vildagliptin added to insulin improved glycaemic control with an associated insulin-sparing effect in patients with type 2 diabetes undergoing haemodialysis and was well tolerated.

Factors associated with the discontinuation of dipeptidyl peptidase-4 inhibitors (DPP-4is) after initiation of insulin

Objective: Type 2 diabetes (T2D) is a prevalent health problem. Oral agents, with the exception of metformin, are often discontinued with the initiation of insulin. The objective was to understand the proportion of patients discontinuing dipeptidyl peptidase-4 inhibitors (DPP-4is) and the reasons for the decision to discontinue.Methods: A retrospective study using a health claims database investigated discontinuation of DPP-4i in adult patients on a dual therapy of metformin and DPP-4i who initiated insulin (n = 3391). An online survey administered to 406 physicians in the US examined reasons for discontinuation. Physicians surveyed included endocrinologists (34.5%), general practitioners (32.5%), internal medicine specialists (30.5%), and diabetologists (2.5%), treating a monthly average of 154 patients.Results: Among patients treated with metformin and DPP-4is who were newly prescribed insulin, 33.3 and 57.3% discontinued DPP-4i therapy within 3 and 12 months, respectively. Patients who discontinued DPP-4i therapy had higher out-of-pocket costs and a greater proportion of renal and liver disease. Top 3 responses for discontinuation included adverse events/tolerability issues (58.9%), lack of efficacy/treatment goals not being met (55.4%) and additional cost of DPP-4i with insulin (48.5%). Top 3 responses for continuing DPP-4i included meeting treatment goals (70.7%), using a lower dose of insulin (65.3%) and good tolerability (48.0%). Physician characteristics, such as physician specialty, age, gender and location impacted to some extent the reasons for treatment decisions.Conclusions: A large proportion of patients discontinue DPP-4is in the real world when initiating insulin. The impact of physician characteristics in treatment decisions highlights the need for enhanced physician training and support as new clinical data emerges and therapy options are available.

The Role of DPP-4 Inhibitors in the Treatment Algorithm of Type 2 Diabetes Mellitus: When to Select, What to Expect

Type 2 diabetes mellitus is a growing global public health problem, the prevalence of which is projected to increase in the succeeding decades. It is potentially associated with many complications, affecting multiple organs and causing a huge burden to the society. Due to its multi-factorial pathophysiology, its treatment is varied and based upon a multitude of pharmacologic agents aiming to tackle the many aspects of the disease pathophysiology (increasing insulin availability [either through direct insulin administration or through agents that promote insulin secretion], improving sensitivity to insulin, delaying the delivery and absorption of carbohydrates from the gastrointestinal tract, or increasing urinary glucose excretion). DPP-4 (dipeptidyl peptidase-4) inhibitors (or “gliptins”) represent a class of oral anti-hyperglycemic agents that inhibit the enzyme DPP-4, thus augmenting the biological activity of the “incretin” hormones (glucagon-like peptide-1 [GLP-1] and glucose-dependent insulinotropic polypeptide [GIP]) and restoring many of the pathophysiological problems of diabetes. They have already been used over more than a decade in the treatment of the disease. The current manuscript will review the mechanism of action, therapeutic utility, and the role of DPP-4 inhibitors for the treatment of type 2 diabetes mellitus.

Double-blind, randomized clinical trial comparing the efficacy and safety of continuing or discontinuing the dipeptidyl peptidase-4 inhibitor sitagliptin when initiating insulin glargine therapy in patients with type 2 diabetes: The CompoSIT-I Study

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.