Comparing Efficacy and Safety of Different Doses of Tirzepatide for the Treatment of Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials

Our study assessed the efficacy and safety of the three primary tirzepatide (TZP) doses, 5 mg, 10 mg, and 15 mg using network meta-analysis to assess their relative impact on type 2 diabetes mellitus (T2DM) treatment. This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Two authors independently screened online databases, including PubMed, Cochrane Library, and Embase. We employed the keywords "Type 2 diabetes OR T2DM or diabetes" AND "Tirzepatide OR LY3298176 OR twincretin OR dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist" AND "randomized controlled trial". The outcomes evaluated in this study comprised changes in hemoglobin (Hb)A1c levels from baseline (%), changes in weight from baseline (Kg), changes in fasting serum glucose from baseline (mg/dL), and occurrences of serious adverse events (SAE), adverse events (AE) and major adverse cardiovascular events (MACE). A total of eight studies met the inclusion criteria and were included in this meta-analysis. Our findings suggest that among the evaluated doses, TZP at 15 mg demonstrated superior effectiveness in reducing HbA1c, weight, and fasting serum glucose compared to doses of 10 mg and 5 mg. Notably, the reduction in HbA1c and weight showed a dose-dependent trend, with the 15 mg dose achieving the most substantial benefits. The safety analysis indicated that while serious adverse events and major adverse cardiovascular events (MACE) did not significantly differ among the three doses, the risk of overall adverse events was notably higher in the 10 mg and 15 mg TZP groups compared to the 5 mg group.

The Potential Utility of Tirzepatide for the Management of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most prevalent endocrinopathy in women of reproductive age. The metabolic dysfunction associated with PCOS increases the probability of developing type 2 diabetes (T2D), endometrial cancer, and cardiovascular disease. Research has shown that the metabolic features of PCOS may be improved by weight loss following treatment with glucagon-like peptide-1 receptor (GLP-1R) agonists. Tirzepatide is a dual GLP-GIP (gastric inhibitory polypeptide) receptor agonist that shares a very similar mechanism of action with GLP-1R agonists, and it is hypothesized that it may be a potential contender in the treatment of PCOS. The success of GLP-1R agonists is usually hindered by their adverse gastrointestinal effects, leading to reduced compliance. The mechanism of action of Tirzepatide partly addresses this issue, as its dual receptor affinity may reduce the intensity of gastrointestinal symptoms. Tirzepatide has been licensed for the treatment of type 2 diabetes and given the metabolic issues and obesity that accompanies PCOS, it may be of value in its management for those PCOS patients who are obese with metabolic syndrome, although it may not benefit those who are of normal weight. This study reviews the current therapies for the treatment of PCOS and evaluates the potential use of Tirzepatide to address the symptoms of PCOS, including reproductive dysfunction, obesity, and insulin resistance.

Diabetic Ketoacidosis in a Patient With Type I Diabetes Treated With a Closed-Loop Sensor-Augmented Insulin Infusion System

Background/Objective

Closed-loop insulin infusion systems (CLSs) such as Tandem t:slim with Control-IQ (t:slim CIQ) improve glycemic control and decrease diabetic ketoacidosis (DKA) risk in type 1 diabetes mellitus (T1DM). We report a case of CLS failure, likely from tirzepatide-induced volume depletion, leading to DKA.

Case Report

A 36-year-old woman with T1DM on t:slim CIQ CLS was prescribed tirzepatide for weight loss. Three months later, 4 days after the last tirzepatide injection, she presented with worsening nausea, vomiting, 50-lbs weight loss, minimal oral intake for 3 days, and positive urine ketone result. Her heart rate was 137 beats/min and respiratory rate was 35 breaths/min, and she had Kussmaul breathing, with dry oral mucosa indicating volume depletion. Laboratory examination showed a fingerstick glucose level of 289 mg/dL, serum glucose level of 322 mg/dL, bicarbonate level of 12 mmol/L, and anion gap of 21 mmol/L confirming high-anion-gap metabolic acidosis, suggesting DKA. A concurrent continuous glucose monitor (CGM) reading was 40 mg/dL. The CLS and CGM were removed. DKA resolved within 72 hours (serum glucose level of 143 mg/dL, anion gap of 8 mmol/L, bicarbonate level of 24 mmol/L) on intravenous insulin and fluids. The CLS and CGM were restarted with good glycemic control. Tirzepatide was discontinued to avoid future episodes of volume depletion.

Discussion

Volume depletion affects interstitial fluid glucose levels due to compensatory mechanisms. This may result in CLS failure due to CGM dependence on interstitial glucose measurements, precipitating DKA.

Conclusion

Patients on CLS therapy should be cautioned against CLS failure in volume-depleted states with interstitial glucose-level changes. A back-up plan with multiple daily insulin injections should be discussed.

Future therapies for obesity

Obesity is a chronic disease associated with increased morbidity and mortality. Bariatric surgery can lead to sustained long-term weight loss (WL) and improvement in multiple obesity-related complications, but it is not scalable at the population level. Over the past few years, gut hormone-based pharmacotherapies for obesity and type 2 diabetes mellitus (T2DM) have rapidly evolved, and combinations of glucagon-like peptide 1 (GLP1) with other gut hormones (glucose-dependent insulinotropic polypeptide (GIP), glucagon, and amylin) as dual or triple agonists are under investigation to enhance and complement the effects of GLP1 on WL and obesity-related complications. Tirzepatide, a dual agonist of GLP1 and GIP receptors, marks a new era in obesity pharmacotherapy in which a combination of gut hormones could approach the WL achieved with bariatric surgery. In this review, we discuss emerging obesity treatments with a focus on gut hormone combinations and the concept of a multimodal approach for obesity management.

Tirzepatide Therapy in a Patient with Type 2 Diabetes Mellitus, Chylomicronemia, and Heterozygosity for Lipoprotein Lipase Deficiency

Background/Objective

A patient with well-controlled type 2 diabetes mellitus (T2DM) and a heterozygote for lipoprotein lipase deficiency (HeLPL) presented with chronic chylomicrons (CMs). Some patients with T2DM can develop CMs due to poor glycemic control or genetic defects that result in a decrease in the lipoprotein lipase (LPL) activity. This study aimed to describe a patient with HeLPL with T2DM and persistent CM on maximal standard lipid-lowering therapy who then used tirzepatide as a novel way to treat CM.

Case Report

A patient with well-controlled T2DM with persistent CM and HeLPL was treated with tirzepatide and titrated to 15 mg/week, resulting in resolution of his CM (triglyceride [TG] level, <850 mg/dL) with a 58% reduction in the serum TG level after 2 months and then an 86% reduction after 5 months of therapy. His A1C level and body weight decreased from 6.9% to 6.3% and by 12 lbs in 2 months and then to 5.6% and by 20 lbs after 5 months, respectively.

Discussion

The resolution of CM and reduction in the TG level by tirzepatide cannot be solely explained by an improvement in glycemic control or a decrease in body weight but may also be related to other effects of tirzepatide.

Conclusion

Tirzepatide caused a significant decrease in the TG level in a patient with CM, T2DM, and HeLPL. The mechanism(s) underlying this effect is not completely understood but warrants further study.

Retatrutide showing promise in obesity (and type 2 diabetes)

INTRODUCTION

Obesity is a major risk factor for cardiovascular disease, diabetes, osteoarthritis, and some cancers. Retatrutide stimulates Glucagon-like peptide 1 (GLP-1), Glucose-dependent insulinotropic polypeptide (GIP) receptors, and glucagon receptors, and is being developed for the treatment of obesity and type 2 diabetes.

AREAS COVERED

A phase 2 clinical trial of retatrutide (LY3437943) in the treatment of obesity. The primary end point was percentage change in weight from baseline to 24 weeks, which ranged from -7.2% to -~18% as the dose of retatrutide increased from 1 mg to 12 mg. The most frequent adverse events were gastrointestinal (nausea, diarrhea, vomiting).

EXPERT OPINION

The results for retatrutide in phase 2 for obesity (and diabetes) are mostly encouraging. Consistent with being a GLP-1 receptor agonist, heart rate was increased by up to 6.7 beats/min by retatrutide, which may be detrimental and offset some of the benefits of weight loss. Presumably, retatrutide is being developed as a challenger to the recently developed weight loss medicines; semaglutide and/or tirzepatide. Thus, comparator studies are needed between retatrutide and these drugs, but none are ongoing and, in my opinion, this lack is a major omission in the development of retatrutide.

Novel Dual Incretin Receptor Agonists in the Spectrum of Metabolic Diseases with a Focus on Tirzepatide: Real Game-Changers or Great Expectations? A Narrative Review

The prevalence of metabolic diseases including type 2 diabetes (T2D), obesity and non-alcoholic fatty liver disease (NAFLD) increases globally. This highlights an unmet need for identifying optimal therapies for the management of these conditions. Tirzepatide is a novel dual incretin receptor agonist (twincretin) that activates both glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors. The aim of this narrative review was to examine the impact of novel twincretins, focusing on tirzepatide, on the management of a wide spectrum of metabolic diseases. Data from preclinical and clinical trials have shown that twincretins significantly reduce blood glucose levels in T2D, and tirzepatide is the first agent of this class that has been approved for the management of T2D. Additionally, the beneficial impact of tirzepatide on weight reduction has been corroborated in several studies, showing that this agent can achieve substantial and sustained weight loss in obese patients with or without T2D. Data also suggest that tirzepatide could be a promising drug for hepatic steatosis reduction in individuals with NAFLD. The remarkable effects of tirzepatide on glycaemic control, weight loss and liver-related outcomes have posed new research questions that are likely to lead to further advancements in the treatment of T2D, obesity and related metabolic disorders.

Tirzepatide 10 and 15 mg compared with semaglutide 2.4 mg for the treatment of obesity: An indirect treatment comparison

AIM

To compare the efficacy of tirzepatide 10 and 15 mg with semaglutide 2.4 mg using an indirect treatment comparison.

MATERIALS AND METHODS

Using SURMOUNT-1 and STEP 1 trial data, mean percentage change in body weight from baseline and odds ratio (OR) of achieving 5% or greater weight loss were compared between tirzepatide 10 and 15 mg at week 72 and semaglutide 2.4 mg at week 68 using matching-adjusted indirect comparison of the efficacy estimand. Sensitivity analyses were completed using different methods, including the Bucher method, also using different estimands and/or time points.

RESULTS

Greater reductions in percentage change in body weight were observed with tirzepatide 10 and 15 mg versus semaglutide 2.4 mg (tirzepatide 10 mg mean difference: -4.67% [95% CI -5.91%, -3.43%]; tirzepatide 15 mg mean difference: -5.92% [95% CI -7.16%, -4.68%]; both P < .001). Similarly, more participants achieved 5% or greater weight loss with tirzepatide 10 mg (OR 2.61 [95% CI 1.48, 4.57]; P < .001) and 15 mg (OR 2.75 [95% CI 1.57, 4.81]; P < .001) compared with semaglutide 2.4 mg. All sensitivity analyses were consistent, except for an OR of achieving 5% or greater weight loss with tirzepatide 10 mg using the Bucher method to analyse the treatment regimen estimand (P = .074).

CONCLUSIONS

Currently there are no direct comparisons of tirzepatide and semaglutide for weight management. Using the matching-adjusted indirect treatment comparison method to compare the efficacy of tirzepatide and semaglutide for chronic weight management, this analysis showed greater weight loss with tirzepatide 10 and 15 mg versus semaglutide 2.4 mg.

Emerging Role of GLP-1 Agonists in Obesity: A Comprehensive Review of Randomised Controlled Trials

Obesity is a chronic disease with high prevalence and associated comorbidities, making it a growing global concern. These comorbidities include type 2 diabetes, hypertension, ventilatory dysfunction, arthrosis, venous and lymphatic circulation diseases, depression, and others, which have a negative impact on health and increase morbidity and mortality. GLP-1 agonists, used to treat type 2 diabetes, have been shown to be effective in promoting weight loss in preclinical and clinical studies. This review summarizes numerous studies conducted on the main drugs in the GLP-1 agonists class, outlining the maximum achievable weight loss. Our aim is to emphasize the active role and main outcomes of GLP-1 agonists in promoting weight loss, as well as in improving hyperglycemia, insulin sensitivity, blood pressure, cardio-metabolic, and renal protection. We highlight the pleiotropic effects of these medications, along with their indications, contraindications, and precautions for both diabetic and non-diabetic patients, based on long-term follow-up studies.

Novel Anti-obesity Therapies and their Different Effects and Safety Profiles: A Critical Overview

Obesity has become an epidemic and a worldwide problem and its treatment is ever-evolving. Apart from diet and exercise, medication and surgery are other options. After disappointing side effects of various obesity drugs, new treatments showed promising results. This review discusses the following anti-obesity drugs: liraglutide, semaglutide, tirzepatide, orlistat, as well as the phentermine/topiramate and bupropion/naltrexone combinations. These drugs have been approved by the Food and Drug Administration (FDA) for weight reduction except for tirzepatide which is still under evaluation. Efficacy and tolerable safety profiles of some of these drugs contribute to the management of obesity and reduce the complications associated with this chronic disease.

Relationship between body weight change and glycaemic control with tirzepatide treatment in people with type 2 diabetes: A post hoc assessment of the SURPASS clinical trial programme

AIM

To assess the relationship between HbA1c and body weight reductions with tirzepatide treatment (5, 10 or 15 mg).

MATERIALS AND METHODS

HbA1c and body weight data at 40 weeks (SURPASS-1, -2 and -5) and 52 weeks (SURPASS-3 and -4) were analysed by trial.

RESULTS

Across the SURPASS clinical trials, HbA1c reductions from baseline were observed in 96%-99%, 98%-99% and 94%-99% of participants treated with tirzepatide 5, 10 and 15 mg, respectively. Moreover, 87%-94%, 88%-95% and 88%-97% of participants, respectively, experienced weight loss associated with HbA1c reductions. Statistically significant associations (correlation coefficients ranging from 0.1438 to 0.3130 across studies; P ≤ .038) between HbA1c and body weight changes were observed with tirzepatide in SURPASS-2, -3, -4 (all doses) and -5 (tirzepatide 5 mg only).

CONCLUSIONS

In this post hoc analysis, consistent reductions in both HbA1c and body weight were observed in most participants treated with tirzepatide at doses of 5, 10 or 15 mg. A statistically significant but modest association between HbA1c and body weight change was observed in SURPASS-2, SURPASS-3 and SURPASS-4, suggesting that both weight-independent and weight-dependent mechanisms are responsible for the tirzepatide-induced improvement in glycaemic control.

Therapeutic Mechanisms and Clinical Effects of Glucagon-like Peptide 1 Receptor Agonists in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) can lead to liver fibrosis and cirrhosis. Recently, glucagon-like peptide 1 receptor agonists (GLP-1RAs), a class of drugs used to treat type 2 diabetes and obesity, have shown therapeutic effects against NAFLD. In addition to reducing blood glucose levels and body weight, GLP-1RAs are effective in improving the clinical, biochemical, and histological markers of hepatic steatosis, inflammation, and fibrosis in patients with NAFLD. Additionally, GLP-1RAs have a good safety profile with minor side effects, such as nausea and vomiting. Overall, GLP-1RAs show promise as a potential treatment for NAFLD, and further studies are required to determine their long-term safety and efficacy.

Tirzepatide: A Promising Drug for Type 2 Diabetes and Beyond

Tirzepatide is a promising drug with dual-acting glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) receptor activation that has revolutionized the treatment of type 2 diabetes mellitus (T2DM) as an adjunct to diet and exercise. In phase 3 clinical trials (SURPASS 1-5), the dose-dependent efficacy and safety of tirzepatide were assessed by once-weekly subcutaneous injection (5 mg, 10 mg, and 15 mg), as monotherapy or combination therapy, in individuals with T2DM. Tirzepatide has been shown to achieve better glycemic control in terms of glycosylated hemoglobin reduction and improved fasting and postprandial glucose levels as compared to other diabetic medications. Moreover, the studies demonstrate a reduction in body weight (-6.2 to -12.9 kg), and other cardiovascular benefits by altering the lipid profile, reducing blood pressure, and visceral adiposity. Tirzepatide has acceptable side effects and is well tolerated, with a low risk of hypoglycemia. The SURPASS 4 clinical trial has shown positive cardiovascular outcomes in people with T2DM and elevated cardiovascular risk. Additionally, encouraging results from SURMOUNT trials and ongoing SURPASS-CVOT studies will shed more light on cardiovascular safety in the future. In this review, we have summarized the clinical trials and their respective outcomes and highlighted the potential future indications for tirzepatide in the management of obesity, heart failure, and nonalcoholic steatohepatitis.

Tirzepatide for the treatment of heart failure in Type 2 diabetes mellitus: (SUR)PASS, or not?

Type 2 diabetes mellitus (T2DM) is a rising pandemic, while cardiovascular disease, including heart failure, represents a frequent concomitance, increasing overall morbidity and mortality and, of course, healthcare cost. Tirzepatide is a dual agonist of glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptors, constituting a novel treatment option in T2DM. This agent exerts additional effects in addition to improvement in glycemic control, which can be of benefit for individuals with T2DM, especially those at risk for or with established cardiovascular disease or heart failure. Current evidence is limited, although suggestive of the cardiovascular safety of tirzepatide. This article provides an overview of available evidence regarding the use of tirzepatide in T2DM, with emphasis on clinical efficacy.

Looking ahead to potential incretin combination therapies for non-alcoholic steatohepatitis in patients with diabetes

INTRODUCTION

There are no drugs approved by regulatory agencies for the treatment of nonalcoholic fatty liver disease (NAFLD); incretin combination therapies are being developed for treatment of type 2 diabetes and research has moved to test their usefulness in NAFLD.

AREAS COVERED

We reviewed the literature on the effectiveness of dual and triple peptides combining receptor agonists of the glucagon-like peptide 1, the glucose-dependent insulinotropic peptide, and glucagon to treat NAFLD and its associated metabolic diseases, and/or the cardiovascular risk intimately connected with the cluster of the metabolic syndrome. Other combination peptides involved the glucagon-like peptide 2 receptor, the fibroblast growth factor 21, the cholecystokinin receptor 2, and the amylin receptor.

EXPERT OPINION

Both dual and triple agonists are promising, based on animal, pharmacokinetic and proof-of concept studies, showing effectiveness both in the presence and the absence of diabetes on a few validated surrogate NAFLD biomarkers, but the majority of studies are still in progress. Considering the long natural history of NAFLD, final proof of their efficacy on primary clinical liver outcomes might be also derived from the analysis of large databases of National Healthcare Systems or Insurance companies, when used in diabetes for improving glycemic control, after careful propensity-score matching.

Is retatrutide (LY3437943), a GLP-1, GIP, and glucagon receptor agonist a step forward in the treatment of diabetes and obesity?

INTRODUCTION

Despite there being a wide range of medicines available for the treatment of type 2 diabetes, the high rate of mortality, suggests treatment needs to be improved. Only a few medicines have shown long-term effectiveness in obesity, and new medicines are urgently needed.

AREAS COVERED

A multiple-ascending dose phase 1b clinical trial of a new drug retatrutide (LY3437943), which in addition to stimulating Glucagon-like peptide 1 (GLP-1) and Glucose-dependent insulinotropic polypeptide (GIP) receptors, stimulates glucagon receptors, in subjects with type 2 diabetes. Retatrutide was relatively safe and pharmacokinetics support once-weekly dosing.

EXPERT OPINION

The role of stimulating glucagon receptors in the treatment of type 2 diabetes and/or obesity is poorly defined and needs to be clarified. Although retatrutide may be superior to the GLP-1 receptor agonist dulaglutide in reducing plasma glucose and body weight, this is not a meaningful comparison, as another GLP-1 receptor agonist (semaglutide) is more potent than dulaglutide at this and may have similar efficacy to retatrutide. Retatrutide also needs to be compared to another Eli Lilly and Company drug, the combined GLP-1 and GIP receptor agonist, tirzepatide. The safety of retatrutide needs to be determined in larger and longer trials.

Achievement of glycaemic targets with weight loss and without hypoglycaemia in type 2 diabetes with the once-weekly glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist tirzepatide: A post hoc analysis of the SURPASS-1 to -5 studies

AIM

To assess composite endpoints combining glycaemic control (HbA1c < 7.0%, ≤ 6.5% or < 5.7%) with weight loss (≥ 5%, ≥ 10% or ≥ 15%) and without hypoglycaemia with tirzepatide in type 2 diabetes (T2D).

MATERIALS AND METHODS

Data from the phase 3 SURPASS programme were evaluated post hoc by trial. Participants with T2D were randomized to tirzepatide (5, 10 and 15 mg), placebo (SURPASS-1,5), semaglutide 1 mg (SURPASS-2) or titrated basal insulin (SURPASS-3,4). The proportions of participants achieving the composite endpoints were compared between tirzepatide and the respective comparator groups at week 40/52.

RESULTS

The proportions of participants achieving an HbA1c value of less than 7.0% with 5% or more weight loss and without hypoglycaemia ranged from 43% to 82% with tirzepatide across the SURPASS-1 to -5 trials versus 4%-5% with placebo, 51% with semaglutide 1 mg and 5% with basal insulin (P < .001 vs. all comparators). The proportions of participants achieving an HbA1c value of less than 7.0% with 10% or more, or 15% or more weight loss and without hypoglycaemia were significantly higher with all tirzepatide doses versus comparators across trials (P < .001 or P < .05). Similar results were observed for all other combinations of endpoints with an HbA1c value of 6.5% or less, or less than 5.7%, with more tirzepatide-treated participants achieving these endpoints versus those in the comparator groups, including semaglutide.

CONCLUSIONS

Across the SURPASS-1 to -5 clinical trials, more tirzepatide-treated participants with T2D achieved clinically meaningful composite endpoints, which included reaching glycaemic targets with various degrees of weight loss and without hypoglycaemia, than those in the comparator groups.

Tirzepatide as Monotherapy Improved Markers of Beta-cell Function and Insulin Sensitivity in Type 2 Diabetes (SURPASS-1)

Context

Tirzepatide is a glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist approved for treatment of type 2 diabetes (T2D). SURPASS-1, a phase 3 trial of tirzepatide monotherapy in people with early T2D, enables evaluating effects of tirzepatide on pancreatic beta-cell function and insulin sensitivity (IS) without other background antihyperglycemic medications.

Objective

Explore changes in biomarkers of beta-cell function and IS with tirzepatide monotherapy.

Design

Post hoc analyses of fasting biomarkers with analysis of variance and mixed model repeated measures.

Setting

Forty-seven sites in 4 countries.

Patients

Four hundred seventy-eight T2D participants.

Intervention

Tirzepatide (5, 10, 15 mg), placebo.

Main Outcome Measures

Analyze biomarkers of beta-cell function and IS at 40 weeks.

Results

At 40 weeks, markers of beta-cell function improved with tirzepatide monotherapy vs placebo with reductions from baseline in fasting proinsulin levels (49-55% vs -0.6%) and in intact proinsulin/C-peptide ratios (47-49% vs -0.1%) (P < .001, all doses vs placebo). Increases from baseline in homeostatic model assessment for beta-cell function (computed with C-peptide) (77-92% vs -1.4%) and decreases in glucose-adjusted glucagon levels (37-44% vs +4.8%) were observed with tirzepatide vs placebo (P < .001, all doses vs placebo). IS improved as indicated by reductions from baseline in homeostatic model assessment for insulin resistance (9-23% vs +14.7%) and fasting insulin levels (2-12% vs +15%), and increases in total adiponectin (16-23% vs -0.2%) and insulin-like growth factor binding protein 2 (38-70% vs +4.1%) with tirzepatide vs placebo at 40 weeks (P ≤ .031, all doses vs placebo, except for fasting insulin levels with tirzepatide 10 mg).

Conclusions

As monotherapy for early T2D, tirzepatide achieved significant improvements in biomarkers of both pancreatic beta-cell function and IS.

Comparative effectiveness of glucagon-like peptide-1 receptor agonists for the management of obesity in adults without diabetes: A network meta-analysis of randomized clinical trials

Tirzepatide is a new glucagon-like peptide-1 receptor agonist (GLP-1RA) that has shown promising results for weight loss. A Bayesian network meta-analysis was conducted to compare the efficacy and safety of GLP-1RAs for obesity management. Embase and MEDLINE were searched looking for randomized clinical trials (RCTs) that evaluated the efficacy of GLP-1RAs for weight loss in patients without diabetes. The main efficacy outcomes evaluated were the mean change in actual and percentage weight loss and the proportion of patients with weight loss of ≥5%-20%. Main safety outcomes evaluated include nausea, vomiting, diarrhea, constipation, loss of appetite, pancreatitis, gallbladder-related disorders, and withdrawal due to adverse events. Seven RCTs with more than 12,300 patients were analyzed, including patients with body mass index (BMI) ≥ 30 kg/m² , or BMI ≥ 27 kg/m² with comorbidities. Weekly tirzepatide 10 and 15 mg resulted in more weight loss than weekly semaglutide 2.4 mg, daily semaglutide 0.4 mg, or liraglutide 3 mg. Tirzepatide and weekly semaglutide demonstrated comparable results but with significantly higher odds of achieving ≥5%-20% weight loss compared with liraglutide. GLP-1RAs triggered more gastrointestinal adverse events than placebo, with no in-between difference. Although all GLP-1RAs lead to significant weight reduction, tirzepatide was associated with better efficacy outcomes while having a comparable safety profile.

Human Epicardial Adipose Tissue Expresses Glucose-dependent Insulinotropic Polypeptide, Glucagon and Glucagon-Like Peptide 1 Receptors as Potential Targets of Pleiotropic Therapies

BACKGROUND

Human Epicardial Adipose Tissue (EAT) plays a crucial role in the development and progression of coronary artery disease, atrial fibrillation and heart failure. Microscopically, EAT is composed of adipocytes, nerve tissues, inflammatory, stromovascular and immune cells. EAT is a white adipose tissue, albeit it also has brown-fat like or beige fat features. No muscle fascia divides EAT and myocardium; this allows a direct interaction and cross talk between the epicardial fat and the myocardium. Thus, it might be a therapeutic target for pharmaceutical compounds acting on G-Protein-Coupled Receptors, such as those for Glucose-dependent Insulinotropic Polypeptide (GIP), Glucagon (GCG) and Glucagon-Like Peptide-1 (GLP-1), whose selective stimulation with innovative drugs has demonstrated beneficial cardiovascular effects. The precise mechanism of these novel drugs and their tissue and cellular target(s) need to be better understood.

AIM

We evaluate whether human EAT expresses GIP, GCG and GLP-1 receptors and whether their presence is related to EAT transcriptome. We also investigated protein expression and cell type localization specifically for GIPR and GCGR.

METHODS

EAT samples were collected from 33 patients affected by cardiovascular diseases undergoing open heart surgery (90.9% males, age 67.2±10.5 years mean ± SD). Microarray and immunohistochemistry analysis were performed.

RESULTS

Microarray analysis showed that GIPR and GCGR messenger Ribonucleic Acids (mRNAs) are expressed in EAT, beyond confirming the previously found GLP-1(3776±1377 arbitrary unit (A.U.), 17.77±14.91 A.U., and 3.41±2.27 A.U., respectively). The immunohistochemical analysis consistently indicates that GIPR and GCGR are expressed in EAT, mainly in macrophages, isolated and in crown-like structures. In contrast, only some mature adipocytes of different sizes showed cytoplasmic immunostaining, similar to endothelial cells and pericytes in the capillaries and pre-capillary vascular structures. Notably, EAT GIPR is statistically associated with the low expression of genes involved in Free Fatty Acid (FFA) oxidation and transport and those promoting FFA biosynthesis and adipogenesis (p<0.01). EAT GCGR, in turn, is related to genes involved in FFA transport, mitochondrial fatty acid oxidation, and white-to-brown adipocyte differentiation, in addition to genes involved in the reduction of fatty acid biosynthesis and adipogenesis (p<0.01).

CONCLUSIONS

Having reported the expression of the GLP-1 receptor previously, here, we showed that GIPR and GCGR similarly present at mRNA and protein levels in human EAT, particularly in macrophages and partially adipocytes, suggesting these G-protein-coupled receptors as pharmacological targets on the ongoing innovative drugs, which seem cardiometabolically healthy well beyond their effects on glucose and body weight..

[The "other" incretin - the therapeutic rediscovery of the glucose-dependent insulinotropic polypeptide]

Among the two incretins that strongly stimulate insulin secretion and are also involved in its physiological regulation in type 2 diabetes, glucagon-like peptide-1 (GLP1) has been the focus of interest for a long time, due to its retained - although reduced - secretagogue nature also in type 2 diabetes. Its receptor agonists were also included in the antidiabetic treatment toolkit. In the light of more recent studies, however, the "other" incretin, the glucose-dependent insulinotropic polypeptide (GIP) has also come into a different light. It turned out that by regulating glucagon and insulin production according to blood sugar levels, it acts as a bifunctional blood sugar stabilizing factor in type 2 diabetes as well. The article reviews new data on the physiology of GIP, its verifiable effects in type 2 diabetes and obesity, the so-called "twincretin" effect as well as the benefits of the double stimulation of the GIP and the GLP1 receptor. It describes the pharmacology of the first dual receptor agonist, tirzepatide, already incorporated in therapeutic recommendations, and the first clinical trials related to its use. In the light of the data so far, the molecule may open new horizons in the treatment of type 2 diabetes and obesity. Orv Hetil. 2023; 164(6): 210-218.

Adverse Events Related to Tirzepatide

Context

Tirzepatide is a dual glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 receptor agonist (GLP-1 RA) approved by the US Food and Drug Administration in May 2022 for patients with type 2 diabetes mellitus (T2DM).

Objective

We aimed to determine the rates of individual adverse events (AEs) related to 3 studied doses of tirzepatide.

Methods

We performed a systematic review with meta-analysis including 5 databases (PubMed, Embase, CINAHL, Scopus, and Web of Science) for all clinical trials reporting AEs related to tirzepatide. The safety data from individual studies were extracted and analyzed through meta-regression to assess rates of individual AEs. Study quality assessment was performed using the National Heart, Lung, and Blood Institute Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

Results

Ten trials (6836 participants) were included. Gastrointestinal (GI) AEs were the most commonly reported AEs and were dose dependent 39% (95% CI, 35%-43%), 46% (95% CI, 42%-49%), and 49% (95% CI, 38%-60%) for the 5, 10, and 15 mg dose, respectively. Among all GI AEs, nausea and diarrhea were most frequent at any dose of tirzepatide. Drug discontinuation due to AEs was highest with the 15 mg dose of tirzepatide (10%). Incidence of mild hypoglycemia (blood glucose < 70 mg/dL) was highest with tirzepatide 10 mg dose 22.6% (9.2%-39.8%). Rates of fatal AEs, severe hypoglycemia, acute pancreatitis, cholelithiasis, and cholecystitis were extremely low (≤ 1%) across all doses of tirzepatide.

Conclusion

Tirzepatide is associated with a dose-dependent increase in incidence of GI AEs and AEs leading to drug discontinuation. Severe hypoglycemia, fatal AEs, acute pancreatitis, cholelithiasis, and cholecystitis are rare with this medication.

Change in pharmacodynamic variables following once-weekly tirzepatide treatment versus dulaglutide in Japanese patients with type 2 diabetes (SURPASS J-mono substudy)

AIM

To evaluate the pharmacodynamic effects of tirzepatide, a novel dual glucagon-like peptide-1 receptor and glucose-dependent insulinotropic polypeptide receptor agonist, compared with dulaglutide in patients with type 2 diabetes.

MATERIALS AND METHODS

SURPASS J-mono was a 52-week, multicentre, randomized, double-blind, parallel, active-controlled, Phase 3 study, conducted in Japan. This substudy of SURPASS J-mono evaluated postprandial metabolic variables and appetite after a meal tolerance test, and body composition measured by bioelectrical impedance analysis.

RESULTS

Of 636 participants in SURPASS J-mono, 48 were included in this substudy and assigned to tirzepatide 5 mg (n = 9), tirzepatide 10 mg (n = 11), tirzepatide 15 mg (n = 9), or dulaglutide 0.75 mg (n = 19). Participants had a mean (standard deviation) age of 58.6 (7.5) years, duration of diabetes of 6.0 (6.3) years, and body mass index of 27.5 (3.5) kg/m² . Mean glycated haemoglobin at baseline was 66 mmol/mol (8.22%). Following a standardized meal test, statistically significant differences in change from baseline in area under the concentration versus time curve from time zero to 6 h after dose for glucose, insulin, glucagon, C-peptide and triglycerides were observed in all tirzepatide treatment arms, except triglycerides at 10 mg, compared with dulaglutide at Week 32. For body composition, tirzepatide 10 mg and 15 mg resulted in a significant reduction in body weight, and all doses of tirzepatide resulted in a significant reduction in body fat mass at Week 52.

CONCLUSIONS

Compared with dulaglutide, tirzepatide showed greater potential for normalizing metabolic factors after a standardized meal. Tirzepatide reduced body weight and body fat mass.

Long-term cost-effectiveness analysis of tirzepatide versus semaglutide 1.0 mg for the management of type 2 diabetes in the United States

AIM

To evaluate the long-term cost-effectiveness of tirzepatide (5, 10 and 15 mg doses), a novel glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist, versus semaglutide 1.0 mg, an injectable glucagon-like peptide-1 receptor agonist, based on the results of the head-to-head SURPASS-2 trial, from a US healthcare payer perspective.

MATERIALS AND METHODS

The PRIME Type 2 Diabetes Model was used to make projections of clinical and cost outcomes over a 50-year time horizon. Baseline cohort characteristics, treatment effects and adverse event rates were derived from the 40-week SURPASS-2 trial. Intensification to insulin therapy occurred when HbA1c reached 7.5%, in line with American Diabetes Association recommendations. Direct costs in 2021 US dollars (US$) and health state utilities were derived from published sources. Future costs and clinical benefits were discounted at 3% annually.

RESULTS

All three doses of tirzepatide were associated with lower diabetes-related complication rates, improved life expectancy, improved quality-adjusted life expectancy and higher direct costs versus semaglutide. This resulted in incremental cost-effectiveness ratios of US$ 75 803, 58 908 and 48 785 per quality-adjusted life year gained for tirzepatide 5, 10 and 15 mg, respectively, versus semaglutide. Tirzepatide remained cost-effective versus semaglutide over a range of sensitivity analyses.

CONCLUSIONS

Long-term projections based on the SURPASS-2 trial results indicate that 5, 10 and 15 mg doses of tirzepatide are likely to be cost-effective versus semaglutide 1.0 mg for the treatment of type 2 diabetes in the United States.

Links between Metabolic Syndrome and Hypertension: The Relationship with the Current Antidiabetic Drugs

Hypertension poses a significant burden in the general population, being responsible for increasing cardiovascular morbidity and mortality, leading to adverse outcomes. Moreover, the association of hypertension with dyslipidaemia, obesity, and insulin resistance, also known as metabolic syndrome, further increases the overall cardiovascular risk of an individual. The complex pathophysiological overlap between the components of the metabolic syndrome may in part explain how novel antidiabetic drugs express pleiotropic effects. Taking into consideration that a significant proportion of patients do not achieve target blood pressure values or glucose levels, more efforts need to be undertaken to increase awareness among patients and physicians. Novel drugs, such as incretin-based therapies and renal glucose reuptake inhibitors, show promising results in decreasing cardiovascular events in patients with metabolic syndrome. The effects of sodium-glucose co-transporter-2 inhibitors are expressed at different levels, including renoprotection through glucosuria, natriuresis and decreased intraglomerular pressure, metabolic effects such as enhanced insulin sensitivity, cardiac protection through decreased myocardial oxidative stress and, to a lesser extent, decreased blood pressure values. These pleiotropic effects are also observed after treatment with glucagon-like peptide-1 receptor agonists, positively influencing the cardiovascular outcomes of patients with metabolic syndrome. The initial combination of the two classes may be the best choice in patients with type 2 diabetes mellitus and multiple cardiovascular risk factors because of their complementary mechanisms of action. In addition, the novel mineralocorticoid receptor antagonists show significant cardio-renal benefits, as well as anti-inflammatory and anti-fibrotic effects. Overall, the key to better control of hypertension in patients with metabolic syndrome is to consider targeting multiple pathogenic mechanisms, using a combination of the different therapeutic agents, as well as drastic lifestyle changes. This article will briefly summarize the association of hypertension with metabolic syndrome, as well as take into account the influence of antidiabetic drugs on blood pressure control.

Tirzepatide suppresses palatable food intake by selectively reducing preference for fat in rodents

AIM

To investigate the role of glucose-dependent insulinotropic polypeptide receptor (GIPR) agonists alone or combined with glucagon-like peptide-1 receptor (GLP-1R) agonists to regulate palatable food intake and the role of specific macronutrients in these preferences.

METHODS

To understand this regulation, we treated mice and rats on several choice diet paradigms of chow and a palatable food option with individual or dual GIPR and GLP-1R agonists.

RESULTS

In mice, the dual agonist tirzepatide suppressed total caloric intake, while promoting the intake of chow over a high fat/sucrose diet. Surprisingly, GIPR agonism alone did not alter food choice. The food intake shift observed with tirzepatide in wild-type mice was completely absent in GLP-1R knockout mice, suggesting that GIPR signalling does not regulate food preference. Tirzepatide also selectively suppressed the intake of palatable food but not chow in a rat two-diet choice model. This suppression was specific to lipids, as GLP-1R agonist and dual agonist treatment in rats on a choice paradigm assessing individual palatable macronutrients robustly inhibited the intake of Crisco (lipid) without decreasing the intake of a sucrose (carbohydrate) solution.

CONCLUSIONS

Decreasing preference for high-caloric, high-fat foods is a powerful action of GLP-1R and dual GIPR/GLP-1R agonist therapeutics, which may contribute to the weight loss success of these drugs.

Obesity pharmacotherapy: incretin action in the central nervous system

The prevalence of obesity is rising, creating an urgent need for efficacious therapies. Recent clinical trials show that tirzepatide, a dual agonist of receptors for the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), yields more weight loss than selective GLP-1 receptor (GLP-1R) agonists. Incretin receptors in the central nervous system (CNS) may contribute to these effects. Yet exactly how each receptor regulates body weight from within the CNS is not clearly understood. It remains especially unclear how GIP receptor (GIPR) signalling contributes to the effects of tirzepatide because both stimulation and inhibition of CNS GIPRs yield weight loss in preclinical models. We summarise current knowledge on CNS incretin receptor pharmacology to provide insight into the potential mechanisms of action of dual GIPR/GLP-1R agonists, with tirzepatide as the exemplar. In addition, we discuss recent developments in incretin-based dual- and tri-agonism for inducing weight loss in obese individuals.

Effect of dual glucose-dependent insulinotropic peptide/glucagon-like peptide-1 receptor agonist on weight loss in subjects with obesity

The occurrence of obesity is an increasing issue worldwide, especially in industrialized countries. Weight loss is important both to treat obesity and to prevent the development of complications. Currently, several drugs are used to treat obesity, but their efficacy is modest. Thus, new anti-obesity treatments are needed. Recently, there has been increased interest in the development of incretins that combine body-weight-lowering and glucose-lowering effects. Therefore, a new drug that simultaneously coactivates both the glucose-dependent insulinotropic polypeptide (GIP) receptor (GIPR) and the glucagon-like peptide-1 receptor (GLP-1R) has been developed. Tirzepatide, the first in this class, improves glycemic control by increasing insulin sensitivity and lipid metabolism as well as by reducing body weight. Combining the activation of the two receptors, greater improvement of β-cell function offers more effective treatment of diabetes and obesity with fewer adverse effects than selective GLP-1R agonists. In the present review, we discuss the progress in the use of GIPR and GLP-1R coagonists and review literature from in vitro studies, animal studies, and human trials, highlighting the synergistic mechanisms of tirzepatide.

A systematic review of the safety of tirzepatide-a new dual GLP1 and GIP agonist - is its safety profile acceptable?

AIMS

Tirzepatide is a novel dual glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 receptor agonist (GLP-1 RA). At present, there is no controversy over its effectiveness, but its safety. We conducted a systematic review to assess the safety of tirzepatide.

METHODS

We searched PubMed, Embase and Cochrane databases for randomized controlled trials (RCTs) of tirzepatide from databases inception to August 28, 2022 and used the Cochrane Systematic Assessment Manual Risk of Bias Assessment Tool (version 5.1) and modified Jadad scale to assess risk of bias. The systematic review was conducted via Revman5.4.

RESULTS

Nine RCTs with a total of 9818 patients were included. The overall safety profile of tirzepatide is similar to GLP-1RAs, except for the hypoglycemia (tirzepatide 15mg, pooled RR=3.83, 95% CI [1.19- 12.30], P=0.02) and discontinuation (tirzepatide 10mg, pooled RR=1.75,95%CI[1.16-2.63], P=0.007 and 15mg, pooled RR=2.03, 95%CI [1.37-3.01], P=0.0004). It also showed that the dose escalation could not rise the occurrence rates of total, severe, gastrointestinal adverse events and hypoglycemia (P>0.05); Compared with 5mg, tirzepatide 10mg and 15mg were associated with more frequent nausea (P<0.001), discontinuation (P<0.05) and injection-site reaction (P<0.01); The rates of vomiting and diarrhea were dose-dependence at the range of 5-15mg.

CONCLUSION

The safety profile of tirzepatide is generally acceptable, similar to GLP-1 RAs. It is necessary to pay attention to its specific adverse events (hypoglycemia and discontinuation) at high doses (10mg or higher). Nausea, vomiting, diarrhea, discontinuation and injection-site reaction were dose-dependence among specific dose ranges.As the heterogeneity in different studies by interventions, the results may be with biases and the further confirmation is needed. Meanwhile, more well-designed trials are needed to control the confounding factors and ensure adequate sample size.

Tirzepatide-Friend or Foe in Diabetic Cancer Patients?

It is a well-accepted fact that obesity and diabetes increase the risk of incidence of different cancers and their progression, leading to a decrease in the quality of life among affected cancer patients. In addition to decreasing the risk of cancers, maintaining a healthy body mass index (BMI)/body weight and/or blood glucose levels within the normal range critically impacts the response to anti-cancer therapy among affected individuals. A cancer patient managing their body weight and maintaining blood glucose control responds better to anti-cancer therapy than obese individuals and those whose blood glucose levels remain higher than normal during therapeutic intervention. In some cases, anti-diabetic/glucose-lowering drugs, some of which are also used to promote weight loss, were found to possess anti-cancer potential themselves and/or support anti-cancer therapy when used to treat such patients. On the other hand, certain glucose-lowering drugs promoted the cancer phenotype and risked cancer progression when used for treatment. Tirzepatide (TRZD), the glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide/gastric inhibitory peptide (GIP) agonist, has recently gained interest as a promising injectable drug for the treatment of type 2 diabetes and was approved by the FDA after successful clinical trials (SURPASS 1/2/3/4 and 5, NCT03954834, NCT03987919, NCT03882970, NCT03730662, and NCT04039503). In addition, the reports from the SURMOUNT-1 clinical trial (NCT04184622) support the use of TRZD as an anti-obesity drug. In the current review article, we examine the possibility and molecular mechanisms of how TRZD intervention could benefit cancer therapeutics or increase the risk of cancer progression when used as an anti-diabetic drug in diabetic patients.

Efficacy and safety of tirzepatide in patients with type 2 diabetes: A systematic review and meta-analysis

Purpose: A systematic review and meta-analysis was conducted to combine the data available from clinical trials and evaluate the clinical efficacy and safety of tirzepatide in people with type 2 diabetes (T2D). Methods: We systematically searched the MEDLINE, Embase, Cochrane Library, and clinical trials registries (https://clinicaltrials.gov) up to 25 March 2022 for randomized controlled trials (RCTs) that compared tirzepatide with placebo or active hypoglycemic drugs in subjects with T2D. Heterogeneity was judged by the I ² value and Cochran's Q test. The randomized effects model was adopted to calculate risk ratios and weighted mean differences (WMDs). The primary outcome was the change from baseline in HbA1c levels. Secondary efficacy endpoints were fasting serum glucose (FSG), change of body weight, blood pressure, fasting lipid profiles, and safety indexes. Results: Six trials comprising 6,579 subjects (4,410 in the tirzepatide group and 2,054 in the control group) fulfilled the pre-specified criteria and were included in the study. Tirzepatide treatment resulted in reducing HbA1c (WMD: -1.07%; 95% confidence intervals [CIs]: -1.44, -0.56), FSG (WMD, -21.50 mg/dl; 95% CI: -34.44, -8.56), body weight (WMD: -7.99 kg; 95% CI -11.36, -4.62), and blood pressure and ameliorated fasting lipid profiles, without increasing hypoglycemia, either as monotherapy or an add-on therapy. Tirzepatide increased the risk of gastrointestinal adverse events mainly in add-on therapy but not in terms of pancreatitis or cholelithiasis. Furthermore, tirzepatide presented a dose-response effect on the reduction in HbA1c and body weight and increase in nausea and vomiting. Conclusion: In patients with type 2 diabetes, tirzepatide shows superior blood glucose control and weight loss performance, without an increased risk of hypoglycemia. Systematic Review Registration: (https://www.crd.york.ac.uk/PROSPERO), identifier (CRD42022319442).

Efficacy of tirzepatide 5, 10 and 15 mg versus semaglutide 2 mg in patients with type 2 diabetes: An adjusted indirect treatment comparison

AIM

To conduct an adjusted indirect treatment comparison (aITC) of the efficacy of tirzepatide 5/10/15 mg versus semaglutide 2 mg in patients with type 2 diabetes.

MATERIALS AND METHODS

The primary analysis was a Bucher aITC of the change from baseline at week 40 in HbA1c (%) and body weight (kg). Aggregate data from the SURPASS-2 study that met the HbA1c inclusion criterion of the SUSTAIN FORTE study and from SUSTAIN FORTE metformin-only treated patients were used for primary analysis.

RESULTS

The SURPASS-2 refined population comprised 238/245/240 and 240 participants for tirzepatide 5/10/15 mg and semaglutide 1 mg, respectively. The SUSTAIN FORTE metformin-only population comprised 222 and 227 participants for semaglutide 1 and 2 mg, respectively. In this aITC, tirzepatide 10 and 15 mg significantly reduced HbA1c versus semaglutide 2 mg with an estimated treatment difference (ETD) of -0.36% (95% confidence interval [CI] -0.63, -0.09) and -0.4% (95% CI -0.67, -0.13), respectively. Tirzepatide 10 and 15 mg significantly reduced body weight versus semaglutide 2 mg with an ETD of -3.15 kg (95% CI -4.84, -1.46) and -5.15 kg (95% CI -6.85, -3.45), respectively. There were no significant differences between tirzepatide 5 mg and semaglutide 2 mg on change from baseline in HbA1c and body weight.

CONCLUSIONS

In this aITC, HbA1c and weight reductions were significantly greater for tirzepatide 10 and 15 mg versus semaglutide 2 mg and were similar for tirzepatide 5 mg versus semaglutide 2 mg. These findings provide comparative effectiveness insights in the absence of a head-to-head clinical trial.

Designing a Dual GLP-1R/GIPR Agonist from Tirzepatide: Comparing Residues Between Tirzepatide, GLP-1, and GIP

Improving type 2 diabetes using incretin analogues is becoming increasingly plausible. Currently, tirzepatide is the most promising listed incretin analogue. Here, I briefly explain the evolution of drugs of this kind, analyze the residue discrepancies between tirzepatide and endogenous incretins, summarize some existing strategies for prolonging half-life, and present suggestions for future research, mainly involving biased functions. This review aims to present some useful information for designing a dual glucagon like peptide-1 receptor/glucose-dependent insulinotropic polypeptide receptor agonist.

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Tirzepatide - a dual GIP/GLP-1 receptor agonist - a new antidiabetic drug with potential metabolic activity in the treatment of type 2 diabetes

The incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are responsible for up to 65% of postprandial insulin secretion. Tirzepatide, developed by Eli Lilly, is a dual GIP/GLP-1 receptor agonist in the form of a synthetic linear peptide; its acylation technology allows it to bind to albumin, thus making it possible to dose the drug once a week. This review summarizes the key characteristics and pharmacokinetics of tirzepatide. The authors present the results of a phase 1, 2, and 3 clinical trial on the effects of tirzepatide on glycaemic and lipid control and the beneficial effects on body weight in a dose-dependent manner in patients with type 2 diabetes mellitus (T2DM). Tirzepatide has the ability to reduce glycaemic levels, improve insulin sensitivity, reduce body weight, and improve lipid metabolism, which is critically important in T2DM. Tirzepatide administered by weekly subcutaneous injections appears to be a promising drug for the treatment of T2DM as well as cardiometabolic disorders. The mechanism of action and safety profile of tirzepatide potentially fills important gaps in the current treatment of T2DM.

Structural determinants of dual incretin receptor agonism by tirzepatide

Tirzepatide is a dual agonist of the glucose-dependent insulinotropic polypeptide receptor (GIPR) and the glucagon-like peptide-1 receptor (GLP-1R), which are incretin receptors that regulate carbohydrate metabolism. This investigational agent has proven superior to selective GLP-1R agonists in clinical trials in subjects with type 2 diabetes mellitus. Intriguingly, although tirzepatide closely resembles native GIP in how it activates the GIPR, it differs markedly from GLP-1 in its activation of the GLP-1R, resulting in less agonist-induced receptor desensitization. We report how cryogenic electron microscopy and molecular dynamics simulations inform the structural basis for the unique pharmacology of tirzepatide. These studies reveal the extent to which fatty acid modification, combined with amino acid sequence, determines the mode of action of a multireceptor agonist.

Tirzepatide (LY3298176) is a fatty-acid-modified, dual incretin receptor agonist that exhibits pharmacology similar to native GIP at the glucose-dependent insulinotropic polypeptide receptor (GIPR) but shows bias toward cyclic adenosine monophosphate signaling at the glucagon-like peptide-1 receptor (GLP-1R). In addition to GIPR signaling, the pathway bias at the GLP-1R may contribute to the efficacy of tirzepatide at improving glucose control and body weight regulation in type 2 diabetes mellitus. To investigate the structural basis for the differential signaling of tirzepatide, mechanistic pharmacology studies were allied with cryogenic electron microscopy. Here, we report high-resolution structures of tirzepatide in complex with the GIPR and GLP-1R. Similar to the native ligands, tirzepatide adopts an α-helical conformation with the N terminus reaching deep within the transmembrane core of both receptors. Analyses of the N-terminal tyrosine (Tyr1^Tzp) of tirzepatide revealed a weak interaction with the GLP-1R. Molecular dynamics simulations indicated a greater propensity of intermittent hydrogen bonding between the lipid moiety of tirzepatide and the GIPR versus the GLP-1R, consistent with a more compact tirzepatide–GIPR complex. Informed by these analyses, tirzepatide was deconstructed, revealing a peptide structure–activity relationship that is influenced by acylation-dependent signal transduction. For the GIPR, Tyr1^Tzp and other residues making strong interactions within the receptor core allow tirzepatide to tolerate fatty acid modification, yielding an affinity equaling that of GIP. Conversely, high-affinity binding with the extracellular domain of the GLP-1R, coupled with decreased stability from the Tyr1^Tzp and the lipid moiety, foster biased signaling and reduced receptor desensitization. Together, these studies inform the structural determinants underlying the function of tirzepatide.

Glucagon-Like Peptide-1 Receptor Agonists and Dual Glucose-Dependent Insulinotropic Polypeptide/Glucagon-Like Peptide-1 Receptor Agonists in the Treatment of Obesity/Metabolic Syndrome, Prediabetes/Diabetes and Non-Alcoholic Fatty Liver Disease-Current Evidence

The obesity pandemic is accompanied by increased risk of developing metabolic syndrome (MetS) and related conditions: non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH), type 2 diabetes mellitus (T2DM) and cardiovascular (CV) disease (CVD). Lifestyle, as well as an imbalance of energy intake/expenditure, genetic predisposition, and epigenetics could lead to a dysmetabolic milieu, which is the cornerstone for the development of cardiometabolic complications. Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) and dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 RAs promote positive effects on most components of the "cardiometabolic continuum" and consequently help reduce the need for polypharmacy. In this review, we highlight the main pathophysiological mechanisms and risk factors (RFs), that could be controlled by GLP-1 and dual GIP/GLP-1 RAs independently or through synergism or differences in their mode of action. We also address the evidence on the use of GLP-1 and dual GIP/GLP-1 RAs in the treatment of obesity, MetS and its related conditions (prediabetes, T2DM and NAFLD/NASH). In conclusion, GLP-1 RAs have already been established for the treatment of T2DM, obesity and cardioprotection in T2DM patients, while dual GIP/GLP-1 RAs appear to have the potential to possibly surpass them for the same indications. However, their use in the prevention of T2DM and the treatment of complex cardiometabolic metabolic diseases, such as NAFLD/NASH or other metabolic disorders, would benefit from more evidence and a thorough clinical patient-centered approach. There is a need to identify those patients in whom the metabolic component predominates, and whether the benefits outweigh any potential harm.

Basal insulin intensification with GLP-1RA and dual GIP and GLP-1RA in patients with uncontrolled type 2 diabetes mellitus: A rapid review of randomized controlled trials and meta-analysis

Tirzepatide, a dual agonist of Glucose-Dependent Insulinotropic Polypeptide (GIP) and Glucagon-Like Peptide 1 (GLP-1) receptors, improved glucose control and reduced body weight in different therapeutic approaches. Herein, we overviewed the role of GIP and GLP-1 in the pathophysiology of type 2 diabetes and systematically reviewed the efficacy and safety of injectable incretin-based therapy added to basal insulin in light of the results of the SURPASS-5 trial. We identified eleven randomized clinical trials. GLP-1 receptor agonists (GLP-1RAs) or Tirzepatide added to basal insulin than rigorously titrated basal insulin significantly ameliorates glucose control (Δ HbA_1c = -1%, 95% CI -1.25; -0.74, I² 94%; Δ FPG = -14.6 mg/dL, 95% CI -21.6-; -7.6, I² 90%; chance to achieve HbA_{1c <}7% = RR 2.62, 95% CI 2.10; 3.26, I² 89%), reduces body weight (Δ = -3.95 kg, 95% CI -5.1, -2.79, I² 96%) without increasing the risk of hypoglycemia (RR = 1.01, 95% CI 0.86; 1.18, I² 7.7%). Tirzepatide provides an impressive weight loss exceeding that observed with GLP-1RAs. Injectable incretin-based therapy plus basal insulin remains a potent and safe therapeutic approach in uncontrolled type 2 diabetes patients previously treated with basal insulin alone. Tirzepatide is expected to ameliorate the management of "diabesity" in this usually difficult-to-treat cluster of patients.

Clinical perspectives on the use of the GIP/GLP-1 receptor agonist tirzepatide for the treatment of type-2 diabetes and obesity

Incretin-based therapies with glucagon-like peptide-1 receptor agonists (GLP-1RA) are already established in the treatment of type 2 diabetes (T2D). The development of novel dual- or triple-receptor agonists that bind to the receptors not only for GLP-1 but also to the receptors for glucose-dependent insulinotropic polypeptide (GIP) and/or glucagon is intended to address different metabolic pathways for carbohydrate, lipid, and protein metabolism simultaneously. Dual- and triple-receptor agonists acting via different receptors and postreceptor pathways seem attractive in view of potentially additive or synergistic effects in the treatment of T2D and obesity. Recently, the first approval for a dual-receptor agonist marks an important step in this development. The GIP/GLP-1-receptor agonist tirzepatide was approved for the treatment of T2D by the Food and Drug Administration (FDA) in the USA for once-weekly subcutaneous injections in May 2022 and has just received a positive opinion from the European Medicines Agency (EMA). Tirzepatide dose-dependently leads to clinically significant reductions in glycemic parameters and body weight and has been shown to have stronger effects in reducing these parameters than standard antidiabetic therapy. This article summarizes the current clinical study program and the respective outcomes and highlights further potential indications for tirzepatide in the treatment of obesity and potentially other comorbidities of T2D.

Efficacy and safety of novel twincretin tirzepatide a dual GIP and GLP-1 receptor agonist in the management of type-2 diabetes: A Cochrane meta-analysis

BACKGROUND

Till date, there is no Cochrane meta-analysis available which has analyzed efficacy and safety of tirzepatide in type-2 diabetes. This meta-analysis was undertaken to address this knowledge gap.

METHODS

Electronic databases were searched for randomized controlled trials (RCTs) involving people with diabetes receiving tirzepatide compared to a placebo/active comparator. Primary outcome was to evaluate changes in HbA1c. Secondary outcomes were to evaluate alterations in blood-glucose, glycemic targets, weight, lipids, and adverse events.

RESULTS

From 34 articles initially screened, data from six RCTs involving 3484 patients were analyzed. Over 12-52 weeks, individuals receiving tirzepatide had significantly greater lowering of HbA1c [mean difference (MD) = -0.75% (95% confidence interval (CI): -1.05 to -0.45); P < 0.01; I ² = 100%], fasting glucose [MD = -0.75 mmol/L (95% CI: -1.05 to- -0.45); P < 0.01; I ² = 100%], 2-h post-prandial-glucose [MD = -0.87 mmol/L (95% CI: -1.12 to -0.61); P < 0.01; I ² = 99%], weight [MD = -8.63 kg (95% CI: -12.89 to -4.36); P < 0.01; I ² = 100%], body mass index [MD = -1.80 kg/m² (95% CI: -2.39 to -1.21); P < 0.01; I ² = 99%], and waist circumference [MD = -4.43 cm (95% CI: -5.31 to -3.55); P < 0.01; I ² = 95%] as compared to dulaglutide, semaglutide, degludec, or glargine. Patients receiving tirzepatide had higher odds of achieving HbA1c <6.5% compared to active controls [odds ratio (OR) = 4.39 (95% CI: 2.44-7.92); P < 0.01; I ² = 90%]. Tirzepatide use had significantly higher odds of weight loss >5% [OR = 19.18 (95% CI: 2.34-157.17); P < 0.01; I ² = 99%], >10% [OR = 21.40 (95% CI: 2.36-193.94); P < 0.01; I ² = 98%], and >15% [OR = 32.84 (95% CI: 2.27-474.33); P = 0.01; I ² = 96%] compared to active-control group. Treatment-emergent adverse events [risk ratio (RR) = 1.43 (95% CI: 1.14-1.80); P < 0.01; I ² = 40%] and severe adverse events [RR = 1.00 (95% CI: 0.64-1.57); P = 1.00; I ² = 49%] were not different. High data heterogeneity and the presence of publication bias limits the grading of current data from "moderate to low."

CONCLUSION

Tirzepatide has impressive glycemic efficacy and weight-loss data over 1-year clinical use. The need for higher grade, long-term efficacy, and safety data remains.

The new dual gastric inhibitory peptide/glucagon-like peptide 1 agonist tirzepatide in type 2 diabetes: Is the future bright?

Tirzepatide is a dual gastric inhibitory peptide/glucagon-like peptide 1 (GIP/GLP-1) receptor agonist formulated as a synthetic linear peptide, based on the native GIP sequence. It has a prolonged half-life of 5 days, which enables once-weekly dosing. Studies have hitherto demonstrated its superiority in achieving optimal glycaemic control and body weight management, as compared with various agents used in the treatment of type 2 diabetes mellitus (T2DM), including GLP-1 receptor agonists. Thus, it is expected to enrich our therapeutic armamentarium in T2DM. However, further experience, notably longer follow-up data and information on cardiovascular effects, is still needed.

Efficacy and Safety of Tirzepatide in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Phase II/III Trials

Tirzepatide is a novel once-a-week dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist, currently under trial to assess glycemic efficacy and safety in people with type 2 diabetes. A systematic review and meta-analysis were conducted to investigate the efficacy of tirzepatide on glycated hemoglobin (HbA1c, %), fasting serum glucose (mg/dL), and body weight (kg) in patients with uncontrolled type 2 diabetes (HbA1c > 7.0%). Mean changes for efficacy and proportions (safety) with corresponding 95% confidence intervals (CIs) were used to provide pooled estimates. A total of four randomized controlled trials, comprising 2783 patients of whom 69.4% (n = 1934) were treated with 5 mg (n = 646), 10 mg (n = 641), or 15 mg (n = 647) of tirzepatide, were compared to the placebo (n = 192) or the selective GLP-1 receptor agonist (n = 523). The pooled analysis showed that tirzepatide treatment resulted in a greater lowering of the HbA1c (−1.94%, 95% CI: −2.02 to −1.87), fasting serum glucose (−54.72 mg/dL, 95% CI: −62.05 to −47.39), and body weight (−8.47, 95% CI: −9.66 to −7.27). We also found that improvement in the HbA1c levels was still maintained at weeks 26 and 40 from the long-term trials. As for safety, only 3% experienced hypoglycemia, and 4% (95% CI: 2 to 6) experienced serious adverse events, while the discontinuation of therapy percentage was 7% (95% CI: 5 to 8). Tirzepatide significantly improved glycemic control and body weight and had an acceptable safety profile, indicating that it is an effective therapeutic option for glucose-lowering in patients with type 2 diabetes mellitus.

Emerging glucagon-like peptide 1 receptor agonists for the treatment of obesity

Introduction: Obesity is a growing threat to public health, increasing risks of numerous diseases and mortality, and impairing quality of life. If current trends continue, more than 1.1 billion individuals will have obesity in 2030, corresponding to almost 2.5 times the number of adults currently living with diabetes. There is a strong interest in developing obesity treatments based on glucagon-like peptide-1 (GLP-1) agonism, which have proved to limit morbidity and mortality in type 2 diabetes.Areas covered: This review provides an overview of current compounds containing GLP-1 receptor agonism in clinical development for obesity, with mono-activity at the GLP-1 receptor (PF-0688296, glutazumab, semaglutide) or engaging one or more other endogenous hormonal systems involved in energy balance and metabolism, including glucagon, oxyntomodulin, glucose-dependent inhibitory peptide and amylin (CT-868, CT-388, AMG 133, tirzepatide, NNC9204-1177, JNJ-54,728,518, SAR425899, pegapamodutide, MK8521, cotadutide, efinopegdutide, BI-456,906, cagrilintide + semaglutide 2,4 mg, HM15211, NNC9204-1706).Expert opinion: Many novel compounds employing GLP-1 receptor agonism are in clinical development. Semaglutide is farthest in clinical development and will presumably become a benchmark for this class of novel anti-obesity compounds.

Dual GIP and GLP-1 Receptor Agonist Tirzepatide Improves Beta-cell Function and Insulin Sensitivity in Type 2 Diabetes

CONTEXT

Novel dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist (RA) tirzepatide demonstrated substantially greater glucose control and weight loss (WL) compared with selective GLP-1RA dulaglutide.

OBJECTIVE

Explore mechanisms of glucose control by tirzepatide.

DESIGN

Post hoc analyses of fasting biomarkers and multiple linear regression analysis.

SETTING

Forty-seven sites in 4 countries.

PATIENTS OR OTHER PARTICIPANTS

Three hundred and sixteen subjects with type 2 diabetes.

INTERVENTIONS

Tirzepatide (1, 5, 10, 15 mg), dulaglutide (1.5 mg), placebo.

MAIN OUTCOME MEASURES

Analyze biomarkers of beta-cell function and insulin resistance (IR) and evaluate WL contributions to IR improvements at 26 weeks.

RESULTS

Homeostatic model assessment (HOMA) 2-B significantly increased with dulaglutide and tirzepatide 5, 10, and 15 mg compared with placebo (P ≤ .02). Proinsulin/insulin and proinsulin/C-peptide ratios significantly decreased with tirzepatide 10 and 15 mg compared with placebo and dulaglutide (P ≤ .007). Tirzepatide 10 and 15 mg significantly decreased fasting insulin (P ≤ .033) and tirzepatide 10 mg significantly decreased HOMA2-IR (P = .004) compared with placebo and dulaglutide. Markers of improved insulin sensitivity (IS) adiponectin, IGFBP-1, and IGFBP-2 significantly increased by 1 or more doses of tirzepatide (P < .05). To determine whether improvements in IR were directly attributable to WL, multiple linear regression analysis with potential confounding variables age, sex, metformin, triglycerides, and glycated hemoglobin A1c was conducted. WL significantly (P ≤ .028) explained only 13% and 21% of improvement in HOMA2-IR with tirzepatide 10 and 15 mg, respectively.

CONCLUSIONS

Tirzepatide improved markers of IS and beta-cell function to a greater extent than dulaglutide. IS effects of tirzepatide were only partly attributable to WL, suggesting dual receptor agonism confers distinct mechanisms of glycemic control.