GLP-1 provoked severe hypoglycemia in an individual with type 2 diabetes and a benign insulinoma

Insulinoma in Patients with Diabetes- A Systematic Review of Previously Reported Cases

Introduction

Paradoxical co-existence of insulinoma and diabetes is extremely rare. Although a few case reports addressed this association, a comprehensive study elucidating this relationship has been lacking. We performed a systematic review of published cases of insulinoma in diabetes.

Methods

We conducted a literature search using PubMed and Google Scholar, employing various combinations of the following terms: 'insulinoma', 'diabetes', 'nesidioblastosis', 'endogenous hyperinsulinism', 'hypoglycaemia', and 'hyperglycaemia' (from January 1900 to January 30, 2024). Exclusion criteria included non-English publications, duplicate articles, reports lacking sufficient data, cases of endogenous hyperinsulinemic hypoglycaemia other than insulinoma, and inaccessible articles. Statistical analysis was performed using appropriate methods.

Results

Sixty patients were considered for the final analysis. Mean age was 61 ± 15 years (range: 17-96 years) with a slight female preponderance; 88.3% had type-2 diabetes with a median duration of 8 years. The median delay in diagnosis of insulinoma was 6 months. Median blood glucose varied from 30.5 mg/dL to 235 mg/dL, with a mean HbA1c of 5.6 ± 1.3% (range: 2.9%-8.2%). Critical sampling data were available in 75% of cases. The median size of the insulinoma was 2 cm. Furthermore, 5.2% of insulinomas were extra-pancreatic. Among pancreatic insulinomas, 14.5% were multi-focal. One-third of cases were malignant. Surgical resection was done in 70.9% of cases, while 40% received drug therapy and 12.7% received both, with 20.7% overall mortality. Malignant insulinoma (P = 0.007), micro-angiopathic (P = 0.018) and macro-angiopathic complications (P = 0.039), and other co-morbidities (P = 0.009) were associated with unfavourable prognosis, while being overweight and obese (P = 0.020) at presentation was associated with favourable prognosis.

Conclusion

This first systematic review provides insights into the uniqueness of insulinoma in diabetes.

Adverse drug reactions of GLP-1 agonists: A systematic review of case reports

BACKGROUND AND AIM

The importance of glucagon-like peptide-1 (GLP-1) agonists is increasing because of its blood sugar controlling and weight loss properties. The data regarding safety of GLP-1 agonists are limited. This study aims to review case reports and case series on adverse drug reactions (ADRs) of GLP-1 agonist.

METHODOLOGY

A comprehensive search was performed in PubMed/Medline, Scopus and Embase to identify literatures. Bibliographic search and open search in Google, Google Scholar, SpringerLink and ResearchGate was performed to identify additional studies. Case reports and case series published the ADRs by the use of GLP-1 agonists in type 2 diabetes patients were included in the study. Reviews, experimental studies, observational studies, grey literature and non English studies were excluded.

RESULTS

The study identified 120 cases of GLP-1 agonists associated ADRs (liraglutide - 46, exenatide - 46, dulaglutide - 20, semaglutide - 4, albiglutide - 2, lixisenatide - 2). The major ADRs reported was gastrointestinal disorders (n = 40) followed by renal (n = 23), dermatologic (n = 14), hepatic (n = 10), immunologic (n = 13), endocrine/metabolic (n = 7), hematologic (n = 3), angioedema (n = 3), neurologic (n = 2), cardiovascular (n = 2) and 1 from each of psychiatric, reproductive, generalized edema problems.

CONCLUSION

Gastrointestinal problems, particularly pancreatitis was the more frequently reported adverse drug reaction associated with GLP-1 agonist. The most adverse drug reactions were observed with liraglutide and exenatide.

Role of Glucagon-Like Peptide-1 (GLP-1) Receptor Agonists in Hypoglycemia

A relatively recent addition to the arsenal of antidiabetic drugs used for the treatment of type 2 diabetes mellitus (T2DM) has been the “incretin mimetics,” a group of drugs that work on the glucagon-like peptide-1 (GLP-1) receptor and enhance insulin secretion from the pancreatic β-cells in a glucose-dependent manner, more potently in hyperglycemic conditions, while suppressing glucagon secretion at the same time. Therefore, it was assumed that this class of drugs would have a lower risk of hypoglycemia than insulin secretagogues like sulphonylureas. However, GLP-1 receptor agonists have been proposed to cause hypoglycemia in healthy normoglycemic subjects implying that their action is not as glucose-dependent as once thought. Other studies concluded that they might not induce hypoglycemia and the risk is dependent on other individual factors. However, the FDA announced that the 12 GLP-1 receptor agonists currently available on the market had potential safety signs and evaluated the need for regulatory action. This review provides an overview of the studies that investigated the possible hypoglycemic effect of GLP-1 receptor agonists. In addition, the current review describes other adverse effects of GLP-1 receptor agonist treatment.

The Discovery and Development of Liraglutide and Semaglutide

The discovery of glucagon-like peptide-1 (GLP-1), an incretin hormone with important effects on glycemic control and body weight regulation, led to efforts to extend its half-life and make it therapeutically effective in people with type 2 diabetes (T2D). The development of short- and then long-acting GLP-1 receptor agonists (GLP-1RAs) followed. Our article charts the discovery and development of the long-acting GLP-1 analogs liraglutide and, subsequently, semaglutide. We examine the chemistry employed in designing liraglutide and semaglutide, the human and non-human studies used to investigate their cellular targets and pharmacological effects, and ongoing investigations into new applications and formulations of these drugs. Reversible binding to albumin was used for the systemic protraction of liraglutide and semaglutide, with optimal fatty acid and linker combinations identified to maximize albumin binding while maintaining GLP-1 receptor (GLP-1R) potency. GLP-1RAs mediate their effects via this receptor, which is expressed in the pancreas, gastrointestinal tract, heart, lungs, kidneys, and brain. GLP-1Rs in the pancreas and brain have been shown to account for the respective improvements in glycemic control and body weight that are evident with liraglutide and semaglutide. Both liraglutide and semaglutide also positively affect cardiovascular (CV) outcomes in individuals with T2D, although the precise mechanism is still being explored. Significant weight loss, through an effect to reduce energy intake, led to the approval of liraglutide (3.0 mg) for the treatment of obesity, an indication currently under investigation with semaglutide. Other ongoing investigations with semaglutide include the treatment of non-alcoholic fatty liver disease (NASH) and its use in an oral formulation for the treatment of T2D. In summary, rational design has led to the development of two long-acting GLP-1 analogs, liraglutide and semaglutide, that have made a vast contribution to the management of T2D in terms of improvements in glycemic control, body weight, blood pressure, lipids, beta-cell function, and CV outcomes. Furthermore, the development of an oral formulation for semaglutide may provide individuals with additional benefits in relation to treatment adherence. In addition to T2D, liraglutide is used in the treatment of obesity, while semaglutide is currently under investigation for use in obesity and NASH.

Molecular imaging in the investigation of hypoglycaemic syndromes and their management

There has been recent progress in molecular imaging using a variety of cellular targets for the investigation of adult non-diabetic hypoglycaemic syndromes and its integration into patient management. These targets include peptide receptors (somatostatin receptors (SSTRs) and glucagon-like peptide-1 receptor (GLP-1R)) the amine precursor uptake and decarboxylation system utilising the diphydroxyphenylaline (DOPA) analogue 6-[¹⁸F]-l-fluoro-l-3,4-dihydroxyphenylalanine (¹⁸F-FDOPA), and glycolytic metabolism with 2-[¹⁸F]fluoro-2-deoxy-d-glucose (FDG). Accurate preoperative localisation and staging is critical to enable directed surgical excision or enucleation with minimal morbidity and preservation of residual pancreatic function. Benign insulinoma has near ubiquitous dense GLP-1R expression enabling accurate localisation with radiolabelled-exendin-4 compounds (e.g. ⁶⁸Ga-NOTA-exendin-4 PET/CT), whilst the rarer and more difficult to manage metastatic insulinoma typically express SSTR and is preferably imaged with radiolabelled-SSTR analogues such as ⁶⁸Ga-DOTA-octreotate (DOTATATE) PET/CT for staging and assessment of suitability for peptide receptor radionuclide therapy (PRRT). Similar to other metastatic neuroendocrine tumours, FDG PET/CT is used in the setting of higher-grade metastatic insulinoma to provide important prognostic information that can guide treatment and determine suitability for PRRT. Interestingly, these three tracers appear to represent a spectrum of differentiation, which we conceptually describe as the 'triple-flop' phenomenon, with GLP-1R > SSTR > FDG in benign insulinoma and the opposite in higher-grade disease. This paper will review the clinical syndromes of adult hypoglycaemia (including a practical overview of the differential diagnoses to be considered), comparison of techniques for insulinoma localisation with emphasis on molecular imaging before discussing its implications for management of metastatic insulinoma.

Efficacy and safety of liraglutide versus sitagliptin, both in combination with metformin, in Chinese patients with type 2 diabetes: a 26-week, open-label, randomized, active comparator clinical trial

AIMS

To compare the efficacy and safety of liraglutide versus sitagliptin as add-on to metformin after 26 weeks of treatment in Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

This 26-week open-label, active comparator trial (NCT02008682) randomized patients (aged 18-80 years) with T2DM inadequately controlled with metformin [glycated haemoglobin (HbA1c) 7.0-10.0% (53-86 mmol/mol)] 1 : 1 to once-daily subcutaneously administered liraglutide 1.8 mg (n = 184) or once-daily oral sitagliptin 100 mg (n = 184), both as add-on to metformin. The primary endpoint was change in HbA1c from baseline to week 26.

RESULTS

Liraglutide was superior to sitagliptin in reducing HbA1c from baseline [8.1% (65 mmol/mol)] to 26 weeks, as evidenced by estimated mean HbA1c change of -1.65% (-18.07 mmol/mol) versus -0.98% (-10.72 mmol/mol), respectively [estimated treatment difference for liraglutide vs sitagliptin of -0.67% (95% CI -0.86, -0.48) or -7.35 mmol/mol (95% CI -9.43; -5.26); p < 0.0001]. More patients receiving liraglutide (76.5%) than sitagliptin (52.6%) achieved the HbA1c target of <7.0% (53 mmol/mol) at week 26 [odds ratio 3.65 (95% CI 2.18, 6.12); p < 0.0001]. Reductions in fasting plasma glucose, 7-point self-measured plasma glucose and body weight were greater with liraglutide than with sitagliptin (p < 0.0001 for all). More patients experienced nausea (14.8% vs 0.5%), diarrhoea (8.2% vs 2.2%) and decreased appetite (10.9% vs 0.5%) with liraglutide than sitagliptin. Two hypoglycaemic episodes were confirmed for liraglutide and one for sitagliptin; none were severe or nocturnal.

CONCLUSIONS

Liraglutide provided better glycaemic control and greater body weight reduction than sitagliptin when administered as add-on to metformin. More patients had nausea, diarrhoea and decreased appetite with liraglutide versus sitagliptin.