Effects of Hepatic Impairment on the Pharmacokinetics of the Dual GIP and GLP-1 Receptor Agonist Tirzepatide

Pediatric Pharmacology for the Primary Care Provider: Advances and Limitations

Despite >1 in 5 children taking prescription drugs in the United States, off-label drug use is common. To increase the study of drugs in children, regulatory bodies have enacted legislation to incentivize and require pediatric drug studies. As a result of this legislation, novel trial approaches, and an increase in personnel with pediatric expertise, there have been numerous advancements in pediatric drug development. With this review, we aim to highlight developments in pediatric pharmacology over the past 6 years for the most common disease processes that may be treated pharmacologically by the pediatric primary care provider. Using information extracted from label changes between 2018 and 2023, the published literature, and Clinicaltrials.gov, we discuss advances across multiple therapeutic areas relevant to the pediatric primary care provider, including asthma, obesity and related disorders, mental health disorders, infections, and dermatologic conditions. We highlight instances in which new drugs have been developed on the basis of a deeper mechanistic understanding of illness and instances in which labels have been expanded in older drugs on the basis of newly available data. We then consider additional factors that affect pediatric drug use, including cost and nonpharmacologic therapies. Although there is work to be done, efforts focused on pediatric-specific drug development will increase the availability of evidence-based, labeled guidance for commonly prescribed drugs and improve outcomes through the safe and effective use of drugs in children.

Glucagon-like peptide-1 analogs: Miracle drugs are blooming?

Glucagon-like peptide-1 (GLP-1), secreted by L cells in the small intestine, assumes a central role in managing type 2 diabetes mellitus (T2DM) and obesity. Its influence on insulin secretion and gastric emptying positions it as a therapeutic linchpin. However, the limited applicability of native GLP-1 stems from its short half-life, primarily due to glomerular filtration and the inactivating effect of dipeptidyl peptidase-IV (DPP-IV). To address this, various structural modification strategies have been developed to extend GLP-1's half-life. Despite the commendable efficacy displayed by current GLP-1 receptor agonists, inherent limitations persist. A paradigm shift emerges with the advent of unimolecular multi-agonists, such as the recently introduced tirzepatide, wherein GLP-1 is ingeniously combined with other gastrointestinal hormones. This novel approach has captured the spotlight within the diabetes and obesity research community. This review summarizes the physiological functions of GLP-1, systematically explores diverse structural modifications, delves into the realm of unimolecular multi-agonists, and provides a nuanced portrayal of the developmental prospects that lie ahead for GLP-1 analogs.

Population pharmacokinetics of the GIP/GLP receptor agonist tirzepatide

Tirzepatide is a first-in-class glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist approved as for the treatment of type 2 diabetes mellitus. A population-based pharmacokinetic (PK) model was developed from 19 pooled studies. Tirzepatide pharmacokinetics were well-described by a two-compartment model with first order absorption and elimination. The tirzepatide population PK model utilized a semimechanistic allometry model to describe the relationship between body size and tirzepatide PK. The half-life of tirzepatide was ~5 days and enabled sustained exposure with once-weekly subcutaneous dosing. The covariate analysis suggested that adjustment of the dose regimen based on demographics or subpopulations was unnecessary. The tirzepatide PK model can be used to predict tirzepatide exposure for various scenarios or populations.

The Body weight Reducing Effects of Tirzepatide in People with and without Type 2 Diabetes: A Review on Efficacy and Adverse Effects

Obesity is becoming more frequent and has several negative health impacts. Recent advances in weight management strategies have primarily resided in pharmaceutical treatments, and the glucagon-like peptide-1 (GLP-1) receptor agonists have shown great potential in terms of body weight reduction in addition to improving glycemic control in patients with type 2 diabetes (T2D). Recently, the dual GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptor agonist tirzepatide has been developed. Tirzepatide has shown strong effects on glycated hemoglobin (HbA1C) levels in several clinical trials including participants with T2D (SURPASS program). In addition to its lowering effect on HbA1C, tirzepatide leads to substantial reductions in body weight, and a series of clinical trials (SURMOUNT program) have investigated the effects on body weight as the primary outcome. In these two trial programs, tirzepatide in doses of 5 mg to 15 mg administered subcutaneously once weekly resulted in body weight reduction of up to 15% in participants with T2D and up to 21% in participants without T2D, despite comparable baseline bodyweight. Across the two trial programs, adverse effects were mainly gastrointestinal (nausea, diarrhea, and vomiting) occurring with similar incidences of vomiting and lower incidences of diarrhea and nausea in trial participants with T2D compared to trials participants without T2D. Overall, discontinuation due to adverse events occurred in 3-7% of participants with no major differences between individuals with and without T2D. The higher weight-reducing efficacy of tirzepatide in trial participants without T2D is currently unexplained and may be partly reflected in dissimilarities in frequencies of gastrointestinal adverse events. The weight reducing effects of tirzepatide hold great promise for weight management in obese patients regardless of the presence of T2D.

Tirzepatide: A Review in Type 2 Diabetes

Tirzepatide (Mounjaro®), a first-in-class dual incretin agonist of the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors, is approved for use as an adjunct to diet and exercise to improve glycaemic control in adults with type 2 diabetes mellitus (T2DM) in the USA, EU, Japan and other countries. It comes as single-dose prefilled pens and single-dose vials. In phase III SURPASS trials, once-weekly subcutaneous tirzepatide, as monotherapy or add-on-therapy to oral glucose-lowering medications and insulin, was superior to the GLP-1 receptor agonists (RAs) dulaglutide 0.75 mg and semaglutide 1 mg as well as basal and prandial insulin for glycaemic control and weight loss in adults with inadequately controlled T2DM. Tirzepatide was generally well tolerated, with a safety profile consistent with that of GLP-1 RAs. Tirzepatide was associated with a low risk of clinically significant or severe hypoglycaemia and no increased risk of major adverse cardiovascular events. Adverse events were mostly mild to moderate in severity, with the most common being gastrointestinal events including nausea, diarrhoea, decreased appetite and vomiting. In conclusion, tirzepatide is a valuable addition to the treatment options for T2DM.

Efficacy and Safety of Tirzepatide in Adults With Type 2 Diabetes: A Perspective for Primary Care Providers

This article reviews the efficacy and safety data of tirzepatide, a once-weekly, novel glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1 (GLP-1) receptor agonist approved in the United States, the European Union, and other regions for the treatment of type 2 diabetes. All doses of tirzepatide demonstrated superiority in reducing A1C and body weight from baseline versus placebo or active comparators. The safety profile of tirzepatide was consistent with that of the GLP-1 receptor agonist class, with mild to moderate and transient gastrointestinal side effects being the most common adverse events. With clinically and statistically significant reductions in A1C and body weight without increased risk of hypoglycemia in various populations, tirzepatide has demonstrated potential as a first-in-class treatment option for many people with type 2 diabetes.

The importance of glucose-dependent insulinotropic polypeptide receptor activation for the effects of tirzepatide

Tirzepatide is a unimolecular co-agonist of the glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors recently approved for the treatment of type 2 diabetes by the US Food and Drug Administration and the European Medicine Agency. Tirzepatide treatment results in an unprecedented improvement of glycaemic control and lowering of body weight, but the contribution of the GIP receptor-activating component of tirzepatide to these effects is uncertain. In this review, we present the current knowledge about the physiological roles of the incretin hormones GLP-1 and GIP, their receptors, and previous results of co-targeting the two incretin hormone receptors in humans. We also analyse the molecular pharmacological, preclinical and clinical effects of tirzepatide to discuss the role of GIP receptor activation for the clinical effects of tirzepatide. Based on the available literature on the combination of GLP-1 and GIP receptor activation, tirzepatide does not seem to have a classical co-activating mode of action in humans. Rather, in vitro studies of the human GLP-1 and GIP receptors reveal a biased GLP-1 receptor activation profile and GIP receptor downregulation. Therefore, we propose three hypotheses for the mode of action of tirzepatide, which can be addressed in future, elaborate clinical trials.

Synergistic Combinations of Gut- and Pancreas-Hormone-Based Therapies: Advancements in Treatments for Metabolic Diseases

Metabolic diseases, such as obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease, and liver disease, have become increasingly prevalent around the world. As an alternative to bariatric surgery, glucagon-like peptide 1 (GLP-1) receptor agonists have been at the forefront of weight loss medication to combat these metabolic complications. Recently, there has been an exciting rapid emergence of new weight loss medications that combine GLP-1 receptor (GLP-1R) agonists with other gut- and pancreatic-derived hormones, such as glucose-dependent insulinotropic polypeptide (GIP) and glucagon (GCG) receptor agonists. Dual-agonist (GLP-1/GIP and GLP-1/GCG) and tri-agonist (GLP-1/GIP/GCG) administration generally result in greater weight loss, reduction of blood sugar and lipid levels, restoration of tissue function, and improvement in whole-body substrate metabolism compared to when GLP-1R agonists are used alone. The aim of this review is to summarize the recent literature of both preclinical and clinical studies on how these emerging gut-peptide therapies further improve weight loss and metabolic health outcomes for various metabolic diseases.

Pharmacokinetic, toxicological, and clinical considerations for the treatment of type 2 diabetes in patients with liver disease: a comprehensive update

INTRODUCTION

Type 2 diabetes and liver disease, mainly metabolic-associated fatty liver disease (MAFLD) and more rarely cirrhosis, coexist in many patients. This duality has direct implications for the physician when choosing glucose-lowering agents, with classical concerns but also recent new hopes.

AREAS COVERED

This updated comprehensive review will consider the pharmacokinetics, the tolerance/safety profile, the benefit/risk balance in cirrhosis, the effects on MAFLD and the risk of hepatocellular carcinoma of old and new glucose-lowering compounds in patients with liver disease, with a special focus on glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors.

EXPERT OPINION

We are currently facing a new paradigm in the management of patients with diabetes and liver disease. From previous reluctance when using antidiabetic agents (except insulin) in diabetic patients with hepatic impairment because of safety concerns, the commercialization of novel glucose-lowering agents has changed the scene. These agents, which have a good safety profile, are associated with weight loss and pleiotropic effects. They have proven their efficacy in improving MAFLD. However, more specific studies are still needed to prove their efficacy in preventing the progression to fibrosis/cirrhosis and confirm this new opportunity for the management of patients with diabetes and liver disease.

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.

An update on tirzepatide for the management of type 2 diabetes: a focus on the phase 3 clinical development program

INTRODUCTION

Tirzepatide, a novel dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist (RA), received regulatory approval from the U.S. Food and Drug Administration (13 May 2022) and marketing authorization from the European Commission (25 September 2022) for the improvement of glycemic control in adults with type 2 diabetes (T2D). In the phase 3 clinical development program (SURPASS), tirzepatide demonstrated superior glycemic and body weight control compared with placebo and active comparators across a spectrum of patients with T2D.

AREAS COVERED

This review summarizes efficacy and safety results of the tirzepatide T2D phase 3 clinical trials that supported regulatory approvals. Additionally, it discusses a meta-analysis assessing tirzepatide cardiovascular (CV) safety, and provides a brief overview of ongoing late-stage clinical trials in patients with T2D. Information in this review was acquired from peer-reviewed published trials, ClinicalTrials.gov, and the manufacturer's website.

EXPERT OPINION

Based on phase 3 clinical trial data, tirzepatide is the most potent glucose and body weight lowering agent available for the management of T2D. The potential for tirzepatide to improve CV outcomes is currently being assessed in a CV outcomes trial (SURPASS CVOT). Results of this trial are highly anticipated and expected in 2024.

Profile of tirzepatide in the management of type 2 diabetes mellitus: design, development, and place in therapy

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is one of the leading causes of morbidity and mortality. Peptide-based multi-targeting agonists represent a new paradigm in metabolic pharmacology as they manifest multiplexed pharmacological actions over mono-agonists. Tirzepatide is a novel dual glucose-dependent insulinotropic polypeptide receptor (GIPR) and glucagon-like peptide-1 receptor (GLP-1R) agonist that has been recently approved by the FDA. This review aims to summarize the available evidence on the discovery, pharmacology, pharmacokinetic, pharmacodynamic, efficacy, and safety of tirzepatide in the pharmacotherapy of T2DM.

AREAS COVERED

We searched PubMed, Embase, and International Pharmaceutical Abstracts to identify relevant papers on tirzepatide use in T2DM. Clinical trial registries were also searched.

EXPERT OPINION

Tirzepatide improves glycemic control compared to baseline, placebo, and active comparators. It is also associated with weight reduction and an improvement in some, but not all, dyslipidemia, cardiovascular risk, and nonalcoholic steatohepatitis (NASH) biomarkers. Tirzepatide has a favorable safety profile with a low risk of hypoglycemia; however, adverse events such as gastrointestinal reactions were frequently reported and sometimes even led to therapy discontinuation. Future research should focus on investigating the role of tirzepatide in obesity, NASH, and cardio-renal benefits. Real-world observational studies are also needed to assess rare and long-term adverse events.

Dual GIP/GLP-1 receptor agonists: New advances for treating type-2 diabetes

Glucagon-like peptide-1 (GLP-1) receptor agonists currently occupy a privileged place in the management of type-2 diabetes (T2D). Dual glucose-dependent insulinotropic polypeptides (GIP/GLP-1) have been recently developed. Tirzepatide is the most advanced unimolecular dual GIP/GLP-1 receptor agonist to be used as once weekly subcutaneous injection in T2D and recently received approval by the European Medicines Agency. Because of the complementarity of action of the two incretins, tirzepatide showed better dose-dependent (5, 10 and 15mg) efficacy (greater reduction in HbA1c and body weight) than placebo, basal insulin or two GLP-1 analogues (dulaglutide and semaglutide) in the SURPASS program. Its cardiovascular protective effect is currently being assessed versus dulaglutide in the SURPASS-CVOT study. Finally, studies for the treatment of obesity (SURMOUNT program) and metabolic-associated fatty liver disease (MAFLD) are also ongoing. Gastrointestinal tolerance of tirzepatide appears comparable to that of GLP-1 analogues, except for higher incidence of diarrhea. Other original molecules have been built, including triple GIP/GLP-1/glucagon receptor agonists. The risk/benefit ratio will decide whether dual (or triple) receptor agonists should replace pure GLP-1 receptor agonists for the management of T2D in the near future, with a significant role in the pharmacotherapy of obesity.

Tirzepatide for the treatment of adults with type 2 diabetes: An endocrine perspective

Tirzepatide is a novel glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 (GLP-1) receptor agonist approved in the United States as an adjunct to diet and exercise to improve glycaemic control in adults with type 2 diabetes and under investigation for use in chronic weight management, major adverse cardiovascular events and the management of other conditions, including heart failure with preserved ejection fraction and obesity and non-cirrhotic non-alcoholic steatohepatitis. The Phase 3 SURPASS 1-5 clinical trial programme was designed to assess efficacy and safety of once-weekly subcutaneously injected tirzepatide (5, 10 and 15 mg), as monotherapy or combination therapy, across a broad spectrum of people with type 2 diabetes. Use of tirzepatide in clinical studies was associated with marked reductions of glycated haemoglobin (-1.87 to -2.59%, -20 to -28 mmol/mol) and body weight (-6.2 to -12.9 kg), as well as reductions in parameters commonly associated with heightened cardiometabolic risk such as blood pressure, visceral adiposity and circulating triglycerides. In SUPRASS-2, these reductions were greater than with the GLP-1 receptor agonist semaglutide 1 mg. Tirzepatide was well tolerated, with a low risk of hypoglycaemia when used without insulin or insulin secretagogues and showed a generally similar safety profile to the GLP-1 receptor agonist class. Accordingly, evidence from these clinical trials suggests that tirzepatide offers a new opportunity for the effective lowering of glycated haemoglobin and body weight in adults with type 2 diabetes.

Tirzepatide: A Dual Glucose-dependent Insulinotropic Polypeptide and Glucagon-Like Peptide-1 Agonist for the Management of Type 2 Diabetes Mellitus

BACKGROUND

Diabetes is a chronic disease that can lead to many complications, and controlling glucose balance is essential. Incretin hormones are produced in the gut and are essential to maintaining glucose homeostasis. Their effects range from increasing insulin synthesis, insulin secretion, and glucose sensing and decreasing glucagon secretion to promote satiety and suppressing appetite. Tirzepatide is a first in class dual glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide (GIP) analog approved for the management of adult patients with type 2 diabetes mellitus as an adjunct to diet and exercise.

PHARMACODYNAMICS AND PHARMACOKINETICS

Tirzepatide is a synthetic chemical structure based on the GIP sequence and consists of 39 amino acid peptides. Tirzepatide increases insulin secretion, reduces glucagon release in a glucose-dependent manner, decreases fasting and postprandial glucose levels, promotes satiety, decreases body weight, and delays gastric emptying. Pharmacodynamics and pharmacokinetics properties of tirzepatide were similar in patients with kidney and hepatic impairment, and its metabolites are excreting through urine and feces.

CLINICAL TRIALS

The SURPASS trials are pivotal phase 3 trials assessing the efficacy and safety of tirzepatide as monotherapy and as an add-on to different antihyperglycemic drugs for the management of T2DM. Tirzepatide consistently showed reductions in HbA1c, as well as benefits with weight loss, with common adverse events reported related to gastrointestinal issues.

THERAPEUTIC ADVANCE

Tirzepatide is a novel first in class dual GIP and glucagon-like peptide-1 agonist that improves overall glycemic control as an adjunct to diet and exercise. It has the potential benefits in other therapeutic areas such as obesity.