Type 1 diabetes: key drug targets and how they could influence future therapeutics.

INTRODUCTION: Despite significant strides made in the management of T1DM, standard management is still insulin analog therapy. Some non-insulin therapies traditionally reserved for the treatment of T2DM have been explored in caring for patients with T1DM, and pancreas transplant is an option for few. However, T1DM remains a challenging disease to manage, encouraging development of novel pharmacologic agents. AREAS COVERED: We retrieved PubMed, Cochrane Library, Scopus, Google Scholar, and ClinicalTrials.gov records to identify studies and articles focused on new pharmacologic advances to treat T1DM. EXPERT OPINION: Recent research has focused on new targets of pharmacologic treatment of T1DM. Beta-cell preservation through immunomodulation or inhibiting inflammation hopes to delay or halt the progression of the disease. Beta cell regeneration through islet cell transplant or modification in transcription pathways aim to reverse the disease effects. Multiple other new targets such as glucagon antagonism and glucokinase activation are also in development as a potential adjunctive therapy. These new therapeutic targets offer the hope of reducing the daily burden of diabetes management with eventual insulin discontinuation for many individuals with T1DM.

Emerging drugs for the treatment of diabetic nephropathy.

INTRODUCTION: Diabetic nephropathy remains a significant economic and social burden on both the individual patient and health-care systems as the prevalence of diabetes increases in the general population. The complex pathophysiology of diabetic kidney disease poses a challenge in the development of effective medical treatments for the disease. However, the multiple facets of diabetic nephropathy also offer a variety of potential strategies to manage this condition. AREAS COVERED: We retrieved PubMed, Cochrane Library, Scopus, Google Scholar, and ClinicalTrials.gov records to identify studies and articles focused on new pharmacologic advances to treat diabetic nephropathy. EXPERT OPINION: RAAS blockers have remained the mainstay of therapy for DM nephropathy for many years, with only recent advancements with SGLT2 inhibitors and nonsteroidal MRAs. Better understanding of the long-term renal effects of ambient hyperglycemia, ranging from hemodynamic changes to increased production of oxidative and pro-inflammatory substances, has evolved our approach to the treatment of diabetic nephropathy. With continuing research for new therapeutics as well as combination therapy, the medical community may be able to better ease the burden of diabetic kidney disease.

The role of Recent Pharmacotherapeutic Options on the Management of Treatment Resistant Type 2 Diabetes.

INTRODUCTION: Type 2 diabetes mellitus is a complex progressive disease leading to chronic hyperglycemia due to insulin resistance and pancreatic beta-cell failure. Intensification of treatment regimens is often necessary due to the overall decline in insulin secretion. Unfortunately, many patients are unable to achieve optimal glycemic control despite the standard of care and thus may be classified as 'treatment resistant'. AREAS COVERED: Newer pharmacotherapeutic agents, either injectable or oral, such as Glucagon-like-peptide-1 receptor agonists (GLP-1RA) and Sodium-glucose Cotransporter-2 (SGLT2) inhibitors are, herein, described. These agents can be used as single agents or fixed combinations that reduce glycemia while lessening the risk for hypoglycemia and renal and cardiovascular diseases. EXPERT OPINION: If individualized target HbA1c is not obtained despite diet, lifestyle, and metformin therapy, then additional oral and injectable therapies should be considered. This may include newer agents such as GLP-1RA and SGLT2 inhibitors alone or in combination that provide renal protection and reduce cardiovascular and hypoglycemic risks. These newer agents have substantial potential for lowering HbA1c through differing but complementary mechanisms. Use of new insulin analogs with GLP-1RA preparations either alone or in fixed-ratio combinations, such as glargine/lixisenatide and degludec/liraglutide, can also reduce the multiple drug adherence burden while improving glycemic control.

Nocturnal hypoglycemia in type 1 and type 2 diabetes: an update on prevalence, prevention, pathophysiology and patient awareness.

INTRODUCTION: Despite considerable progress in diabetes treatment, prevalence of nocturnal hypoglycemia in type 1 diabetes mellitus (T1DM) and advanced insulin treated type 2 diabetes mellitus (T2DM) remains high. AREAS COVERED: The present manuscript describes the prevalence of night-time hypoglycemia as reported in observational and randomized controlled trials. Factors that affect the risk of hypoglycemia are highlighted. The authors also describe impaired awareness of hypoglycemia and available preventive methods. EXPERT OPINION: Prevention of nocturnal hypoglycemia includes behavioral, dietary and pharmacologic interventions. The most recent development with the lowest rate of hypoglycemia is sensor-augmented pumps with predictive low glucose suspend technology. These pumps combine continuous subcutaneous insulin infusion with continuous glucose monitoring and use various algorithms to predict and stop hypoglycemia before it develops.

Sodium-glucose cotransporter 2 inhibitors for the management of type 2 diabetes.

INTRODUCTION: Sodium-glucose cotransporter (SGLT) 2 inhibitors reduce glucose reabsorption in the kidney, increase glucosuria, and improve glycemia. Besides glycemic efficacy, the class also lowers risk of cardiovascular and renal disease. AREAS COVERED: The authors describe late phase trials of empagliflozin, canagliflozin, dapagliflozin, and ertugliflozin. Safety and efficacy endpoints in monotherapy, combination therapy, cardiovascular, and renal outcomes trials have been identified and presented. EXPERT OPINION: SGLT2 inhibitors appear to be safe and effective agents that improve glycemia when used alone or in combination with any other approved antihyperglycemic medications. Other beneficial effects include reductions in body weight and blood pressure, improvements in renal outcomes, all-cause mortality, cardiovascular mortality, and worsening heart failure.

Update on the effects of GLP-1 receptor agonists for the treatment of polycystic ovary syndrome.

Introduction: Glucagon-like peptide-1 receptor agonists (GLP-1 RA) offer a unique opportunity to simultaneously address various comorbid associated conditions and phenotypic presentations of polycystic ovary syndrome (PCOS) as these agents improve insulin sensitivity, reduce cardiovascular disease (CVD) risk, result in weight loss, and improve nonalcoholic fatty liver disease.Areas covered: The authors describe trials conducted during the last 5 years and provide an update on exenatide and liraglutide use in PCOS women. Information from the studies investigating GLP-1 RAs effects on reducing CVD risk in PCOS is also presented.Expert opinion: Exenatide and liraglutide are good options for the treatment of PCOS when used alone or in combination with metformin. Especially strong consideration should be given to GLP-1 RAs when developing treatment strategies for PCOS women who are overweight or obese, glucose intolerant, have CVD or its attendant risk factors, and/or are seeking treatment for infertility.

Effects of anti-diabetic treatments in type 2 diabetes and fatty liver disease.

Introduction: Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are significant non-communicable diseases that often affect individuals concurrently. In individuals with both T2DM and NAFLD, there is evidence that anti-diabetic therapies may demonstrate potential combined beneficial metabolic and reduced hepatic inflammatory effects.Areas covered: A PubMed and Google Scholar search was performed to find relevant literature. Included studies focused on individuals with T2DM and NAFLD receiving anti-diabetic treatments including bariatric surgery, insulin sensitizers, incretin mimetics, and SGLT2 inhibitors. Additional articles highlight investigational treatments.Expert opinion: In individuals with T2DM and NAFLD, 5-10% weight loss or bariatric surgery if unable to lose weight or maintain weight loss are appropriate. GLP-1 receptor agonists and SGLT2 inhibitors result in weight loss, appear safe and may provide beneficial hepatic outcomes. Whether their effects are related to favorable weight changes or intrinsic hepatic effects is unclear. Thiazolidinediones have advantageous anti-hyperglycemic and hepatic effects but individuals must be monitored for weight gain and edema. Metformin and DPP-4 inhibitor beneficial hepatic effects remain debated. There are opportunities to standardize markers and imaging of NAFLD. Studies powered to evaluate the possible cardiovascular benefits of anti-diabetic therapies in individuals with T2DM and NAFLD are needed.

Considerations when using alpha-glucosidase inhibitors in the treatment of type 2 diabetes.

Introduction: Alpha-glucosidase inhibitors (AGIs) - oral antihyperglycemic drugs, inhibit upper gastrointestinal enzymes that break down complex carbohydrates into glucose. As a result, the absorption of glucose is delayed, postprandial glucose reduced, and glycemic control improved.Areas covered: In this review, the authors describe the current recommendations on the use of the three major approved AGIs (acarbose, miglitol, voglibose). Efficacy and safety parameters together with ethnic considerations have been highlighted throughout the manuscript. The article also discusses potential diabetes prevention and cardiovascular effects of these medications.Expert opinion: The overall safety and efficacy of this class of drug appears to be high: AGIs do not increase the risk of hypoglycemia, do not cause weight gain; they also significantly improve postprandial hyperglycemia, have been associated with the reduction in risk factors for cardiovascular disease and may also delay the progression of prediabetes to T2DM. In general, we continue to believe that acarbose, miglitol, and voglibose should be used as third-line add on treatment options to other anti-hyperglycemic agents. However, this class can have earlier consideration in elderly and/or when metformin is contraindicated.

An update on the safety and efficacy of oral antidiabetic drugs: DPP-4 inhibitors and SGLT-2 inhibitors.

INTRODUCTION: Oral antidiabetic medications are important in many type 2 diabetes care plans. AREAS COVERED: The article summarizes the cardiovascular and renal safety data for DPP-4 inhibitors and SGLT-2 inhibitors and specific safety data particular to each class. EXPERT OPINION: DPP-4 and SGLT-2 inhibitors provide unique anti-hyperglycemic mechanisms. The cardiovascular safety profiles of DPP-4 inhibitors are promising, but do not show the strong CV risk reduction of empagliflozin and canagliflozin. The heart failure signal associated with DPP-4 inhibitor use is unclear with differing agents, demonstrating increased risk or maybe even protective effects. The risk reduction in cardiovascular disease associated with SGLT-2 inhibitors has translated to recommendations to consider these therapies early in the treatment pathway. Both classes have potential safety concerns that necessitate appropriate patient selection and thorough education on potential side-effects. DPP-4 inhibitors are considered to have neutral or in some studies beneficial renoprotective effects. SGLT-2 inhibitor safety effects on the kidney are more complex. There are reports of acute kidney injury occurring soon after initiating SGLT-2 inhibitor therapy. However, there are large recent studies that have demonstrated the beneficial effect of SGLT-2 inhibitors in slowing the progression of established chronic kidney disease.

Using DPP-4 inhibitors to modulate beta cell function in type 1 diabetes and in the treatment of diabetic kidney disease.

INTRODUCTION: DPP-4 inhibitors have pleomorphic effects that extend beyond the anti-hyperglycemic labeled use of the drug. DPP-4 inhibitors have demonstrated promising renal protective effects in T2DM and T1DM and protective effects against immune destruction of pancreatic beta-cells in T1DM. AREAS COVERED: The efficacy of DPP-4 inhibitors in the treatment of diabetic kidney disease and possible adjunct with insulin in the treatment of T1DM to preserve beta-cell function. Pertinent literature was identified through Medline, PubMed and ClinicalTrials.gov (1997-November 2018) using the search terms T1DM, sitagliptin, vildagliptin, linagliptin, beta-cell function, diabetic nephropathy. Only articles are written in the English language, and clinical trials evaluating human subjects were used. EXPERT OPINION: DPP-4 inhibitors can be used safely in patients with diabetic kidney disease and do not appear to exacerbate existing diabetic nephropathy. Linagliptin reduces albuminuria and protects renal endothelium from the deleterious effects of hyperglycemia. The effects of DPP-4 inhibitors on preserving beta-cell function in certain subtypes of T1DM [e.g. Latent Autoimmune Diabetes in Adult (LADA) and Slowly Progressive Type 1 Diabetes (SPIDDM)] are encouraging and show promise.

Oral semaglutide for the treatment of type 2 diabetes.

INTRODUCTION: Glucagon-like peptide-1 (GLP-1) receptor agonists are highly potent antihyperglycemic drugs that impose low risk of hypoglycemia and also result in body weight reduction. Currently, all approved members of the class require administration by injection. Areas covered: This manuscript reviews oral semaglutide-an experimental GLP-1 receptor agonist in phase-3 clinical development. Available pharmacological and clinical data of the drug are reviewed, and important end-points described. Expert opinion: Oral peptide delivery has become possible with the discovery of absorption enhancers. The clinical development program of once-daily oral semaglutide has shown superiority in reducing glycosylated hemoglobin and body weight in comparison with placebo and active comparators (sitagliptin, liraglutide, and empagliflozin). Safety and tolerability of oral semaglutide is in line with injectable members of the class. Delayed gastric emptying, local increase in pH, and enhanced absorption do not seem to affect the exposure of a number of other oral drugs that have been tested (metformin, digoxin, oral contraceptive ethinylestradiol/levonorgestrel, lisinopril, warfarin, furosemide and rosuvastatin). Clinical questions for further investigation include the effectiveness and safety of oral semaglutide in cardiovascular indications.

Effects of Severe Hypoglycemia on Cardiovascular Outcomes and Death in the Veterans Affairs Diabetes Trial.

OBJECTIVE: To determine the risk factors for severe hypoglycemia and the association between severe hypoglycemia and serious cardiovascular adverse events and cardiovascular and all-cause mortality in the Veterans Affairs Diabetes Trial (VADT). RESEARCH DESIGN AND METHODS: This post hoc analysis of data from the VADT included 1,791 military veterans (age 60.5 ± 9.0 years) with suboptimally controlled type 2 diabetes (HbA1c 9.4 ± 2.0%) of 11.5 ± 7.5 years disease duration with or without known cardiovascular disease and additional cardiovascular risk factors. Participants were randomized to intensive (HbA1c <7.0%) versus standard (HbA1c <8.5%) glucose control. RESULTS: The rate of severe hypoglycemia in the intensive treatment group was 10.3 per 100 patient-years compared with 3.7 per 100 patient-years in the standard treatment group (P < 0.001). In multivariable analysis, insulin use at baseline (P = 0.02), proteinuria (P = 0.009), and autonomic neuropathy (P = 0.01) were independent risk factors for severe hypoglycemia, and higher BMI was protective (P = 0.017). Severe hypoglycemia within the past 3 months was associated with an increased risk of serious cardiovascular events (P = 0.032), cardiovascular mortality (P = 0.012), and total mortality (P = 0.024). However, there was a relatively greater increased risk for total mortality in the standard group compared with the intensive group (P = 0.019). The association between severe hypoglycemia and cardiovascular events increased significantly as overall cardiovascular risk increased (P = 0.012). CONCLUSIONS: Severe hypoglycemic episodes within the previous 3 months were associated with increased risk for major cardiovascular events and cardiovascular and all-cause mortality regardless of glycemic treatment group assignment. Standard therapy further increased the risk for all-cause mortality after severe hypoglycemia.

Peroxisome proliferator-activated receptor alpha-mediated drug toxicity in the liver.

INTRODUCTION: Drug-induced hepatic injury is the most common cause of acute liver failure in the United States. Peroxisome proliferator-activated receptor alpha (PPARα)-mediated drugs are included among the approximately 900 natural and synthetic substances, which have shown hepatotoxicity. Areas covered: This review will focus on fibrates - PPARα agonists and their implication in causing liver injury. Expert opinion: Compelling evidence for fibrate-induced hepatotoxicity is not available. Results have been varying because several large randomized clinical trials have reported similar elevations of plasma transaminase levels in fibrate or placebo treated groups. On the other hand, one meta-analysis has reported an increased risk of hepatotoxicity when fibrates are combined with statins. Fibrate induced clinically apparent liver damage has been demonstrated in case reports. However, there is a wide spectrum of clinical phenotypic presentations of these cases (onset of injury, pattern of enzyme elevation and resolution of the symptoms), which reduces the ability to identify specific cause and effect of any putative fibrate-induced hepatotoxicity. Thus, the current recommendations for using fibrates include monitoring of aminotransferase levels especially if combined with statins and discontinuation of the treatment only if the levels persist above three times the upper limit of normal.

Subcutaneous semaglutide (NN9535) for the treatment of type 2 diabetes.

INTRODUCTION: It is critical for individuals with type 2 diabetes mellitus (T2DM) to maintain optimal glycemia while avoiding hypoglycemia, control body weight, and reduce cardiovascular risk. The GLP-1 receptor agonists stimulate glucose-dependent insulin release (low risk of hypoglycemia), inhibit glucagon secretion, slow gastric emptying and suppress appetite (weight loss). The new members of the class are available as once daily or weekly injections. Additionally, some members of the class have demonstrated reduced cardiovascular risk. Areas covered: This manuscript describes semaglutide - a new investigational long acting GLP-1 receptor agonist. The key trials from the clinical development process are reviewed and important end-points highlighted. Expert opinion: Once-weekly semaglutide has shown superiority in reducing glycosylated hemoglobin and body weight in comparison with placebo and active comparators when used as monotherapy or in combination treatment. In addition, semaglutide improved markers of ß-cell function and have shown cardiovascular risk reduction similar to once daily liraglutide. Although, overall semaglutide safety was comparable to other GLP-1 receptor agonists (low risk of hypoglycemia and high frequency of gastrointestinal side effects), increase in retinopathy complications requires further investigation.

Incretin-based therapy in type 2 diabetes: An evidence based systematic review and meta-analysis.

Incretin based therapies such as dipeptidyl peptidase-4 inhibitors (DPP-4i) and glucagon-like peptide-1 receptor agonists (GLP-1Ra) are increasingly used for the treatment of Type 2 diabetes mellitus. In clinical practice and in previously performed clinical trials, these agents are often used in combination with other oral anti-diabetic agents (OADs) and Insulin. Prior meta-analytic reviews however do not adequately address the impact of background therapy and active comparator arms. Accordingly, we aimed to further investigate the efficacy of incretin based therapies by updating existing reviews by including clinical trial evidence after 2008; estimating the pooled effect of incretin therapies on glycemic efficacy and weight-loss, stratified by comparator therapy (placebo, mono-therapy, etc.), estimating the impact of background OADs and within class (GLP-1Ra or DPP-4i) comparative efficacy, on glycemia control. 82 randomized controlled trials after 2008 with glycemic control and weight loss as primary end-points were included. Both DPP-4i and GLP-1Ra reduced HbA1c, but only GLP-1Ra caused weight loss when compared to either active comparator drugs or placebo. GLP-1Ra were more effective than DPP-4i in glycemia lowering. Long acting GLP-1Ra were more effective in HbA1c lowering than short-acting agents but with similar weight loss effect. The effect of DPP-4i incretin glycemic efficacy was not modified by background therapy used in the study.

Understanding the impact of hypoglycemia on the cardiovascular system.

INTRODUCTION: Hypoglycemia occurs commonly in insulin requiring individuals with either Type 1 or Type 2 Diabetes. AREAS COVERED: This article will review recent information on the pro-inflammatory and pro-atherothrombotic effects of hypoglycemia. Additionally, effects of hypoglycemia on arrhythmogenic potential and arterial endothelial dysfunction will be discussed. Effects of hypoglycemia on cardiovascular morbidity and mortality from large clinical studies in Type 1 and Type 2 DM will also be reviewed. EXPERT COMMENTARY: The relative and absolute risk of severe hypoglycemia leading to death and serious adverse events in both cardiovascular and other organ systems has been highlighted following the publication of recent large clinical trials focused on glucose control and outcomes. It would be helpful if future studies could develop broader end points to include minor and moderate hypoglycemia as well as more robust methods for capturing hypoglycemia contemporaneously with adverse events. In addition, perhaps consideration of including hypoglycemia as a primary outcome, may help identify the possible cause and effect of hypoglycemia on cardiovascular morbidity and mortality.

The care of pregestational and gestational diabetes and drug metabolism considerations.

INTRODUCTION: Normal pregnancy development involves gradual decline in insulin sensitivity, which sometimes requires pharmacotherapy. Insulin is the drug of choice for gestational and pregestational diabetes. Metabolism of traditional insulins results in inadequate onset and duration of action and marked peak activity. These properties increase risk of excessive glucose excursions, which are especially undesirable during pregnancy. Insulin analogs have been emerging as a safer and more effective treatment of diabetes during pregnancy. Areas covered: This manuscript reviews currently used antihyperglycemic agents: fast and long-acting insulins, metformin and glyburide. Trials demonstrating their efficacy and safety during pregnancy are described. Certain drug metabolism considerations (e.g. affinity to IGF-1) are emphasized. Expert opinion: The theories that insulin analogs bind to immunoglobulin and cross placenta have been disproved. Lispro, aspart, glargine and detemir do not transfer across the placenta and do not result in adverse maternal and neonatal outcomes. In addition, favorable pharmacokinetic profiles (rapid onset and 24-hour near peakless activity) substantially reduce blood glucose variability including hypoglycemia. We believe that insulin analogs should be given strong consideration for the treatment of diabetes during pregnancy. Metformin has also proven to be safe and may be considered as an initial single agent for milder gestational diabetes.

GLP-1 receptor agonists in the treatment of polycystic ovary syndrome.

INTRODUCTION: Polycystic ovarian syndrome (PCOS) affects many women of child-bearing age and is characterized by hyperandrogenism, ovulatory and metabolic dysfunction. A primary treatment goal is weight reduction. The weight loss effects of glucagon-like peptide-1 receptor agonists (GLP-1RA), previously demonstrated in diabetic and obese non-diabetic patients, offer a unique opportunity to expand the medical options available to PCOS patients. Areas covered: Available clinical trials of glucagon-like peptide-1 receptor agonist therapy in PCOS were reviewed. Literature was searched from PubMed using appropriate search terms up to November 2016. Expert commentary: The available studies of GLP-1 RA therapy in the treatment of excess body weight in women with PCOS demonstrate that exenatide and liraglutide are effective in weight reduction either as monotherapy or in combination with metformin. A few studies showed that androgens may be modestly decreased and menstrual frequency may be increased. Eating behavior may be improved with liraglutide therapy. Glucose parameters are generally improved. GLP-1RAs were well-tolerated, with nausea being the most significant adverse side effect. Barriers to utilization may be the short duration studies, lack of familiarity of the medication, the route of administration (injection) and the variable outcomes on ovulation and hyperandrogenism.