A randomized, double-blind, placebo-controlled, pharmacokinetic and pharmacodynamic study of a fixed-dose combination of phentermine/topiramate in adolescents with obesity

Update on Pediatric Anti-obesity Medications-Current Landscape and Approach to Prescribing

PURPOSE OF REVIEW

To review the current medical therapies available for treatment of obesity in children and adolescents less than 18 years old in the United States and outline the approach to their use.

RECENT FINDINGS

Obesity is a chronic disease with increasing prevalence in children and adolescents in the United States. Over the past few years, more FDA-approved medical treatments for obesity, such as GLP-1 receptor agonists, have emerged for patients less than 18 years old. Furthermore, there are medications with weight loss effects that can be used off-label for obesity in pediatric patients. However, access to many of these medications is limited due to age restrictions, insurance coverage, and cost. Medical options are improving to provide treatment for obesity in pediatric populations. FDA and off-label medications should be considered when appropriate to treat children and adolescents with obesity. However, further studies are needed to evaluate the efficacy and long-term safety of FDA-approved and off-label medications for obesity treatment in pediatric patients.

Reductions of food intake and body weight in diet-induced obese rats following chronic treatment with a monomeric peptide multiagonist

INTRODUCTION

While therapies based on endogenous gut peptides such as glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1RAs) have been compelling therapeutic agents for obesity and type 2 diabetes (T2D), only a few have achieved long-term weight loss and all have shown significant side-effects, including nausea/malaise and gastrointestinal ailments.

OBJECTIVE

As the pathophysiology of obesity is driven by dysregulation of multiple, inter-related, pathways, we tested a novel peptide targeting multiple receptors of complementary neurocircuits regulating the controls of energy balance.

METHODS

Response to daily injections of GEP44, a GLP-1R and neuropeptide Y1R and Y2R receptor (Y1R/Y2R) triple agonist was tested vs. the GLP-1R agonist liraglutide (LIRA) in diet-induced obese (DIO) male and female rats. Glucose tolerance tests after intraperitoneal injection of glucose (IPGTT) were performed at baseline and after 14-d of treatment in GEP44 treated rats. Other metabolic parameters were assessed in blood at the end of a 28-d intervention.

RESULTS

Upon conclusion at 28-d, body weight reduction compared to vehicle was -15.6%/-11.9% in response to GEP44, vs. -9.7%/-5.1% after LIRA, males, and females, respectively. Significant reductions of cumulative food intake occurred over 28-d in female rats treated with GEP44 (-30%; p < 0.0001), vs. LIRA (-10%), and in male rats GEP44 (-39%; p < 0.0001), vs. LIRA (-20%; p = 0.003). In IPGTTs, a similar stimulation glucose induced insulin secretion was noted in rats treated with GEP44 and LIRA.

CONCLUSION

The strong reductions of body weight in response to long-term applications of the triple agonist GEP44 confirms the therapeutic potential of targeting multiple receptors for achieving more robust and potentially more sustained improvement of energy balance.

Anti-obesity Medication Use for Adolescent Metabolic and Bariatric Surgery Patients: A Systematic Literature Review

Bariatric surgery, in combination with pharmacotherapy, has been proven to be successful in combatting weight regain in adults; however, the use of anti-obesity medications to augment weight loss in adolescents before and after bariatric surgery is not well studied. In adolescent obese patients, the efficacy of anti-obesity pharmacotherapy before and after bariatric surgery on weight loss compared to no interventions in various studies was investigated. A PubMed literature search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed to identify studies related to the pharmacologic treatment of obesity in adolescents with a history of bariatric surgery. Inclusion criteria consisted of clinical trials, case reports, case series, chart reviews, systematic reviews, and meta-analyses written in English and published between 2005 and 2022 using our search criteria. Exclusion criteria were studies that investigated adults, did not include pharmacotherapy, and were not relevant to the outcome of interest. The initial search yielded 1275 results, which was reduced to 879 after removal of duplicates. After applying exclusion criteria, the number of articles was reduced to 63. Full articles were examined and 44 were excluded due to relevance. Nineteen articles were included in the qualitative analysis. A total of 2471 adolescents were treated with various types of pharmacotherapy, 65 of whom had a history of bariatric surgery. The results showed varied effects of pharmacotherapy with the different medications studied. However, the 65 patients were included in cohorts of patients with no history of bariatric surgery. These studies did not include data specific to adolescent bariatric surgery patients.  There is a wealth of evidence highlighting the efficacy of pharmacotherapy in assisting with weight loss in adolescents with obesity; however, our literature search showed a lack of studies focusing on the use of pharmacotherapy in the adolescent bariatric surgery population. Potential limitations include missing studies in our literature search, the variability in methods between studies, and the lack of standardized quality assessment. Additionally, studies involving our objective of choice regarding bariatric surgery with anti-obesity medication were limited. Clinical trials to determine the efficacy of medications as an adjunct to bariatric surgery in preventing weight regain and leading to optimal weight loss in this population are of utmost importance.

Childhood Obesity, Diabetes. and Cardiovascular Disease Risk

This mini-review aims to briefly summarize the pathophysiology of childhood obesity, type 2 diabetes mellitus (T2DM), and cardiovascular disease (CVD) risk in children and adolescents. Recent data on efficacy of lifestyle interventions, medications, and metabolic surgery for obesity, T2DM, and CVD risk factors are also reviewed. We conducted a PubMed search of English-language original and review articles relevant to childhood obesity, T2DM, and CVD risk factors, and biomarkers in children with an emphasis on recent publications. Childhood obesity arises from an intricate interaction between genetic, physiologic, environmental, and socioeconomic factors. The rise in the prevalence of childhood obesity is associated with the development of comorbidities including T2DM and CVD at an early age. A multipronged approach is central to the detection, monitoring, and management of childhood obesity and associated adverse metabolic consequences.

Treatment of hypothalamic obesity in people with hypothalamic injury: new drugs are on the horizon

Hypothalamic obesity (HO) is a complex and rare disorder affecting multiple regulatory pathways of energy intake and expenditure in the brain as well as the regulation of the autonomic nervous system and peripheral hormonal signaling. It can be related to monogenic obesity syndromes which often affect the central leptin-melanocortin pathways or due to injury of the hypothalamus from pituitary and hypothalamic tumors, such as craniopharyngioma, surgery, trauma, or radiation to the hypothalamus. Traditional treatments of obesity, such as lifestyle intervention and specific diets, are still a therapeutic cornerstone, but often fail to result in meaningful and sustained reduction of body mass index. This review will give an update on pharmacotherapies of HO related to hypothalamic injury. Recent obesity drug developments are promising for successful obesity intervention outcomes.

A Narrative Review: Phentermine and Topiramate for the Treatment of Pediatric Obesity

The prevalence of pediatric obesity has increased exponentially over the past four decades. The American Academy of Pediatrics recently released updated clinical practice guidelines highlighting the importance of identifying pediatric obesity as a chronic disease. The guidelines support consideration of concurrent treatment with intensive lifestyle interventions, obesity pharmacotherapy, and bariatric surgery. The dramatic rise in pediatric obesity has spurred interest in utilizing obesity pharmacotherapy to support sustained weight reduction in pediatric cohorts, in the hopes of preventing the emergence of later-appearing, significant co-morbidities. Despite the enormous demand, the obstacles posed by performance of needed clinical trials in the pediatric population markedly limits available pharmacotherapy for the treatment of obesity in pediatrics. Currently, there are five medications approved by the Food and Drug Administration for use in youth with obesity. In 2022, the phentermine/topiramate (PHEN/TPM), once-daily, controlled-release, combination product received FDA approval, for the indication of chronic weight management, in youth with obesity, ages 12 years and older. The objectives of this narrative review are to: (1) Review the mechanism of action of phentermine and topiramate, (2) Summarize the safety and efficacy data of topiramate and phentermine use as both monotherapies and in combination, and (3) Discuss clinical practice guidelines and clinical implications, for the use of these agents in youths with obesity.

Pharmacological Treatments and Natural Biocompounds in Weight Management

The obesity pandemic is one of society’s most urgent public health concerns. One-third of the global adult population may fall under obese or overweight by 2025, suggesting a rising demand for medical care and an exorbitant cost of healthcare expenditure in the coming years. Generally, the treatment strategy for obese patients is largely patient-centric and needs dietary, behavioral, pharmacological, and sometimes even surgical interventions. Given that obesity cases are rising in adults and children and lifestyle modifications have failed to produce the desired results, the need for medical therapy adjunct to lifestyle modifications is vital for better managing obesity. Most existing or past drugs for obesity treatment target satiety or monoamine pathways and induce a feeling of fullness in patients, while drugs such as orlistat are targeted against intestinal lipases. However, many medications targeted against neurotransmitters showed adverse events in patients, thus being withdrawn from the market. Alternatively, the combination of some drugs has been successfully tested in obesity management. However, the demand for novel, safer, and more efficacious pharmaceutical medicines for weight management does exist. The present review elucidates the current understanding of the available anti-obesity medicines of synthetic and natural origin, their main mechanisms of action, and the shortcomings associated with current weight management drugs.

Risk Factors, Clinical Consequences, Prevention, and Treatment of Childhood Obesity

Obesity might adversely affect the health and well-being of children and their families. Childhood obesity has crucial implications for health, both during childhood and as they age. It is highly associated with many acute problems and is commonly present during childhood, making visits and hospital admissions polarized in this group of children. The problems that may affect these children can be medical, such as asthma, chronic inflammation, orthopedic abnormalities, liver disease, diabetes mellitus or dyslipidemia. Long-term consequences of cardiovascular risk factors, the persistence of obesity and premature mortality are common among adults who had obesity during their early lives. Additionally, they could also suffer from psychological issues, such as low self-esteem, which puts them at risk of a much more serious psychosocial problem that may lead to depression, as well as a disruption in educational achievements and social relationships. A healthy diet, physical activity, adequate sleep, and limited screen time are all preventive measures that should be implemented at the family and community levels, preferably through well-structured programs. Furthermore, pharmacological management of childhood obesity is limited and only used after non-pharmacological interventions have failed or in the late stages of obesity. However, recent guidelines advocate the early use of medical interventions. Approved pharmacotherapeutic options include orlistat, phentermine/topiramate combination and liraglutide. There are several other options approved primarily for other specific forms of obesity or for other indications, including setmelanotide, metformin, lisdexamfetamine, zonisamide and fluoxetine. Bariatric surgery is a safe and effective option in cases with extreme obesity and comorbidities considering the need for long-term monitoring and support for cases and their families post-surgery. This review aims to discuss and highlight the recent evidence regarding risk factors, clinical consequences, prevention, and treatment of childhood obesity.

Phentermine/Topiramate: Pediatric First Approval

Phentermine/topiramate extended-release capsule (Qsymia^®) is a fixed-dose combination of phentermine and topiramate, which is being developed by VIVUS (a subsidiary of Icahn Enterprises) for the treatment of obesity, sleep apnoea syndrome, type 2 diabetes mellitus and non-alcoholic steatohepatitis (NASH). The once-daily formulation of phentermine (a sympathomimetic amine) and topiramate is designed to combat obesity by decreasing appetite and increasing satiety. In July 2022, phentermine/topiramate received its first approval in the USA, as an adjunct to a reduced-calorie diet and increased physical activity, for chronic weight management in pediatric patients aged ≥ 12 years with BMI in the 95th percentile or greater standardized for age and sex. Phentermine/topiramate is approved in the US and South Korea for obesity in adults. Clinical development of phentermine/topiramate for sleep apnoea syndrome and type-2 diabetes in obese patients and preclinical development for NASH is ongoing in the US. This article summarizes the milestones in the development of phentermine/topiramate leading to this pediatric first approval for chronic weight management in adolescents.

Medical treatment of weight loss in children and adolescents with obesity

Obesity remains one of the biggest health problems both in adults and children. Lifestyle modification, including diet and exercise, continues to be the mainstay of obesity prevention and treatment. Unfortunately, lifestyle modifications are often unsuccessful. Pharmacological treatment of obesity in pediatric patients can be applied in selected cases, and not before evidence of failure of the multidisciplinary lifestyle intervention. In this narrative review, we revised the most up-to-date evidence on medical treatment of weight loss in children and adolescents with obesity, including FDA- or EMA-approved and -experimented, not approved, drugs for pediatric population. Multidisciplinary treatment of childhood obesity, regulation of appetite control, energy balance and body weight were also discussed, in order to clarify the indications and mechanism action of drugs. Despite a substantial number of medications used for the treatment of obesity in adults, a limited number of drugs are approved by the drug regulatory agencies for pediatric population. Further research is needed to evaluate the efficacy and safety of novel pharmacological approaches for treatment of pediatric obesity in order to optimize weight management for children and adolescents and limit the development obesity-related comorbidities.

The Related Metabolic Diseases and Treatments of Obesity

Obesity is a chronic disease characterized by the abnormal or excessive accumulation of body fat, affecting more than 1 billion people worldwide. Obesity is commonly associated with other metabolic disorders, such as type 2 diabetes, non-alcoholic fatty liver disease, cardiovascular diseases, chronic kidney disease, and cancers. Factors such as a sedentary lifestyle, overnutrition, socioeconomic status, and other environmental and genetic conditions can cause obesity. Many molecules and signaling pathways are involved in the pathogenesis of obesity, such as nuclear factor (NF)-κB, Toll-like receptors (TLRs), adhesion molecules, G protein-coupled receptors (GPCRs), programmed cell death 1 (PD-1)/programmed death-ligand 1 (PD-L1), and sirtuin 1 (SIRT1). Commonly used strategies of obesity management and treatment include exercise and dietary change or restriction for the early stage of obesity, bariatric surgery for server obesity, and Food and Drug Administration (FDA)-approved medicines such as semaglutide and liraglutide that can be used as monotherapy or as a synergistic treatment. In addition, psychological management, especially for patients with obesity and distress, is a good option. Gut microbiota plays an important role in obesity and its comorbidities, and gut microbial reprogramming by fecal microbiota transplantation (FMT), probiotics, prebiotics, or synbiotics shows promising potential in obesity and metabolic syndrome. Many clinical trials are ongoing to evaluate the therapeutic effects of different treatments. Currently, prevention and early treatment of obesity are the best options to prevent its progression to many comorbidities.

Anti-obesity weight loss medications: Short-term and long-term use

As obesity prevalence increases, more and more drugs that assist with weight loss have been developed. Numerous weight loss drugs had been approved, but many have also been withdrawn based on their lack of efficacy as well as safety concerns. Initial approaches in developing weight loss drugs was by increasing physiological energy expenditure and suppressing the appetite. Subsequently, as more physiological mechanisms for weight gain has been unearthed, drugs targeting newly discovered receptors and/or enzymes have been introduced with improved safety profiles and fewer psychological adverse events. Additionally, drugs targeting hunger or satiety signaling have been actively studied, and have shown increased adoption by physicians. Studies have also evaluated drugs that target metabolic tissues-such as adipose tissue or muscle-to promote weight loss, however to-date nothing has carried on into clinical practice. Starting with a brief history of early obesity treatments, this review evaluates current weight loss pharmaceutical options based on their duration of therapy status.

Phentermine/Topiramate for the Treatment of Adolescent Obesity

BACKGROUND

Antiobesity medication may be useful for the treatment of pediatric obesity, yet few safe and effective options exist. We evaluated phentermine/topiramate (PHEN/TPM) for weight management in adolescents with obesity.

METHODS

This 56-week, randomized, double-blind trial enrolled adolescents 12 to less than 17 years of age with obesity. Participants were randomly assigned 1:1:2 to receive either placebo (n=56), mid-dose PHEN/TPM (7.5 mg/46 mg; n=54), or top-dose PHEN/TPM (15 mg/92 mg; n=113), respectively. All participants received lifestyle therapy. The primary end point was mean percent change in body-mass index (BMI) from randomization to week 56.

RESULTS

Participants had a mean (±SD) age of 14.0±1.4 years and a mean (±SD) BMI of 37.8±7.1 kg/m²; 54.3% were female. The primary end point of percent change in BMI at week 56 showed differences from placebo of -10.44 percentage points (95% CI, -13.89 to -6.99; P<0.001) and -8.11 percentage points (95% CI, -11.92 to -4.31; P<0.001) for the top and mid doses of PHEN/TPM, respectively. Differences from placebo in percent change in triglycerides nominally favored PHEN/TPM (mid dose, -21%; 95% CI, -40 to -2; and top dose, -21%; 95% CI, -38 to -4), as did differences in percent change in high-density lipoprotein cholesterol (HDL-C) (mid dose, 10%; 95% CI, 3 to 18; and top dose, 9%; 95% CI, 2 to 15). The incidence of participants reporting at least one adverse event was 51.8%, 37.0%, and 52.2% in the placebo, mid-dose, and top-dose groups, respectively. Serious adverse events were reported for two participants in the top-dose group.

CONCLUSIONS

PHEN/TPM at both the mid and top doses offered a statistically significant reduction in BMI and favorably impacted triglyceride and HDL-C levels in adolescents with obesity. (Funded by VIVUS LLC, with project support provided by Covance LLC; ClinicalTrials.gov number, NCT03922945.).

Melanocortin-4 receptor complexity in energy homeostasis,obesity and drug development strategies

The melanocortin-4 receptor (MC4R) has been critically investigated for the past two decades, and novel findings regarding MC4R signalling and its potential exploitation in weight loss therapy have lately been emphasized. An association between MC4R and obesity is well established, with disease-causing mutations affecting 1% to 6% of obese patients. More than 200 MC4R variants have been reported, although conflicting results as to their effects have been found in different cohorts. Most notably, some MC4R gain-of-function variants seem to rescue obesity and related complications via specific pathways such as beta-arrestin (ß-arrestin) recruitment. Broadly speaking, however, dysfunctional MC4R dysregulates satiety and induces hyperphagia. The picture at the mechanistic level is complicated as, in addition to the canonical G stimulatory pathway, the ß-arrestin signalling pathway and ions (particularly calcium) seem to interact with MC4R signalling to contribute to or alleviate obesity pathogenesis. Thus, the overall complexity of the MC4R signalling spectra has broadened considerably, indicating there is great potential for the development of new drugs to manage obesity and its related complications. Alpha-melanocyte-stimulating hormone is the major endogenous MC4R agonist, but structure-based ligand discovery studies have identified possible superior and selective agonists that can improve MC4R function. However, some of these agonists characterized in vitro and in vivo confer adverse effects in patients, as demonstrated in clinical trials. In this review, we provide a comprehensive insight into the genetics, function and regulation of MC4R and its contribution to obesity. We also outline new approaches in drug development and emerging drug candidates to treat obesity.

Childhood obesity: A review of current and future management options

Obesity is becoming increasingly prevalent in paediatric populations worldwide. In addition to increasing prevalence, the severity of obesity is also continuing to rise. Taken together, these findings demonstrate a worrying trend and highlight one of the most significant challenges to public health. Childhood obesity affects multiple organs in the body and is associated with both significant morbidity and ultimately premature mortality. The prevalence of complications associated with obesity, including dyslipidaemia, hypertension, fatty liver disease and psychosocial complications are becoming increasingly prevalent within the paediatric populations. Treatment guidelines currently focus on intervention with lifestyle and behavioural modifications, with pharmacotherapy and surgery reserved for patients who are refractory to such treatment. Research into adult obesity has established pharmacological novel therapies, which have been approved and established in clinical practice; however, the research and implementation of such therapies in paediatric populations have been lagging behind. Despite the relative lack of widespread research in comparison to the adult population, newer therapies are being trialled, which should allow a greater availability of treatment options for childhood obesity in the future. This review summarizes the current evidence for the management of obesity in terms of medical and surgical options. Both future therapeutic agents and those which cause weight loss but have an alternative indication are also included and discussed as part of the review. The review summarizes the most recent research for each intervention and demonstrates the potential efficacy and limitations of each treatment option.

Utilization of Topiramate as an Adjunct to Lifestyle Intervention for Weight Loss in Pediatric Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease is the most common chronic liver disease in children and has become the leading indication for liver transplantation in adults. The primary treatment modality is lifestyle modification to promote weight loss, which is challenging to achieve and maintain. Adjunctive weight loss medications, such as topiramate, are commonly used off-label in adults and children with obesity and found to be safe and effective. We report an adolescent male with severe obesity and nonalcoholic steatohepatitis refractory to aggressive lifestyle intervention. He was safely treated with topiramate with resultant weight loss, reduction in body mass index z-score, improvement in liver enzymes, and resolution of hepatic steatosis. This is the first report of using topiramate in a pediatric patient with obesity and nonalcoholic steatohepatitis. Topiramate should be considered in pediatric nonalcoholic fatty liver disease to help curb emotional eating and promote satiety in cases refractory to lifestyle intervention alone.

Targeting Energy Expenditure-Drugs for Obesity Treatment

Obesity and overweight are associated with lethal diseases. In this context, obese and overweight individuals infected by COVID-19 are at greater risk of dying. Obesity is treated by three main pharmaceutical approaches, namely suppressing appetite, reducing energy intake by impairing absorption, and increasing energy expenditure. Most compounds used for the latter were first envisaged for other medical uses. However, several candidates are now being developed explicitly for targeting obesity by increasing energy expenditure. This review analyzes the compounds that show anti-obesity activity exerted through the energy expenditure pathway. They are classified on the basis of their development status: FDA-approved, Withdrawn, Clinical Trials, and Under Development. The chemical nature, target, mechanisms of action, and description of the current stage of development are described for each one.

The Effects of Anti-obesity Pharmacotherapy Interventions on Psychosocial Factors Among Adolescents with Obesity: a Scoping Review

PURPOSE OF REVIEW

The purpose of this review was to investigate and synthesize psychosocial outcomes from pharmacotherapy experimental trials for weight loss among adolescents with obesity.

RECENT FINDINGS

There is a paucity of research regarding pharmacological interventions for adolescents with obesity. These studies have typically reported reductions in weight, and side effects have been inconsistently described. Overall, medication seems to be a safe and effective obesity treatment modality for adolescents with obesity. Six articles were included in this review. Studies varied in medication type, medication dosing, lifestyle components, psychosocial measures, measurement intervals, and psychosocial outcomes. All studies found a reduction in weight and/or BMI. Studies were often underpowered to detect differences in psychosocial variables, which were always considered secondary or exploratory outcomes. Future research should include psychosocial outcomes as a primary endpoint of pharmacological interventions for adolescent obesity. Ultimately, the treatment of the complex disease of obesity deserves to be assessed through multiple health domains extending beyond weight reduction.

Diabesity: the combined burden of obesity and diabetes on heart disease and the role of imaging

Diabesity is a term used to describe the combined adverse health effects of obesity and diabetes mellitus. The worldwide dual epidemic of obesity and type 2 diabetes is an important public health issue. Projections estimate a sixfold increase in the number of adults with obesity in 40 years and an increase in the number of individuals with diabetes to 642 million by 2040. Increased adiposity is the strongest risk factor for developing diabetes. Early detection of the effects of diabesity on the cardiovascular system would enable the optimal implementation of effective therapies that prevent atherosclerosis progression, cardiac remodelling, and the resulting ischaemic heart disease and heart failure. Beyond conventional imaging techniques, such as echocardiography, CT and cardiac magnetic resonance, novel post-processing tools and techniques provide information on the biological processes that underlie metabolic heart disease. In this Review, we summarize the effects of obesity and diabetes on myocardial structure and function and illustrate the use of state-of-the-art multimodality cardiac imaging to elucidate the pathophysiology of myocardial dysfunction, prognosticate long-term clinical outcomes and potentially guide treatment strategies.