Dasiglucagon Treatment for Postprandial Hypoglycemia After Gastric Bypass: A Randomized, Double-Blind, Placebo-Controlled Trial

Dumping syndrome: Update on pathophysiology, diagnosis, and management

BACKGROUND

Dumping syndrome is a complex of gastrointestinal symptoms originally studied in peptic ulcer surgery patients. At present, it is most prevalent in patients who underwent bariatric, upper gastrointestinal cancer or anti-reflux surgery. The symptom pattern comprises early and late dumping symptoms. Several management options have been reported including nutritional, pharmacological and surgical approaches.

AIMS AND METHODS

In this study, we aimed to review the current evidence on dumping syndrome definition, diagnosis and treatment, including preliminary data from newer pharmacological studies.

RESULTS

Current pathophysiological concepts and analyses of provocative tests has led to a clear definition of dumping syndrome, including both early and late dumping symptoms. The term postbariatric hypoglycemia represents a limited focus on late dumping only. The diagnosis relies on recognition of symptoms and signs in a patient with appropriate surgical history; and can be confirmed by provocative testing or registration of spontaneous hypoglycemia. The initial treatment focuses on dietary intervention, to which meal viscosity enhancers and/or the glycosidase inhibitor acarbose can be added. The most effective therapy is the use of short- or long-acting somatostatin analogues, which is however expensive and entails side effect issues. In case of refractory hypoglycemia, diazoxide or SGLT2 inhibitors can be considered, based on limited evidence. In refractory patients, continuous enteral feeding or (rarely) surgical reinterventions have been advocated, although not supported by solid evidence. Therapies under current evaluation include the broad-spectrum somatostatin analogue pasireotide, GLP-1 receptor antagonists, GLP-1 receptor agonists and administration of stable forms of glucagon are currently under study.

CONCLUSIONS

Dumping syndrome is a well-defined but probably under-diagnosed complication of upper gastrointestinal, especially bariatric, and surgeries. Diagnosis is confirmed by a provocative test and incremental therapies starting with diet, adding meal viscosity enhancers or glycosidase inhibitors and adding somatostatin analogues in refractory cases. A number of emerging therapies targeting intestinal propulsion, peptide hormone effects and hypoglycemic events are under evaluation.

New Lessons from the gut: Studies of the role of gut peptides in weight loss and diabetes resolution after gastric bypass and sleeve gastrectomy

It has been known since 2005 that the secretion of several gut hormones changes radically after gastric bypass operations and, although more moderately, after sleeve gastrectomy but not after gastric banding. It has therefore been speculated that increased secretion of particularly GLP-1 and Peptide YY (PYY), which both inhibit appetite and food intake, may be involved in the weight loss effects of surgery and for improvements in glucose tolerance. Experiments involving inhibition of hormone secretion with somatostatin, blockade of their actions with antagonists, or blockade of hormone formation/activation support this notion. However, differences between results of bypass and sleeve operations indicate that distinct mechanisms may also be involved. Although the reductions in ghrelin secretion after sleeve gastrectomy would seem to provide an obvious explanation, experiments with restoration of ghrelin levels pointed towards effects on insulin secretion and glucose tolerance rather than on food intake. It seems clear that changes in GLP-1 secretion are important for insulin secretion after bypass and appear to be responsible for postbariatric hypoglycemia in glucose-tolerant individuals; however, with time the improvements in insulin sensitivity, which in turn are secondary to the weight loss, may be more important. Changes in bile acid metabolism do not seem to be of particular importance in humans.

Canagliflozin or acarbose versus placebo to ameliorate post-bariatric hypoglycaemia - The HypoBar I randomized clinical trial protocol

INTRODUCTION

Post-bariatric hypoglycaemia (PBH) is a rare yet disabling clinical condition, mostly reported after Roux-en-Y gastric bypass (RYGB) surgery. RYGB is one of the most widely used and effective bariatric procedures. The pathophysiology of PBH remains unclear, and treatment options are limited in effectiveness and/or carry significant side effects. Acarbose slows carbohydrates digestion and absorption and is generally considered first-line pharmacological treatment for PBH but its gastrointestinal side effects limit patient compliance. Canagliflozin inhibits intestinal and renal sodium-dependent glucose absorption and reduces postprandial excursions of glucose, insulin and incretins after RYGB - effects that could be beneficial in ameliorating PBH.

AIMS

The trial aims to investigate how blood glucose levels are affected during daily living in subjects with PBH during treatment with canagliflozin or acarbose compared with placebo, and to study the meal-induced entero-endocrine mechanisms implied in the treatment responses.

METHODS

In a double-blinded, randomized, crossover clinical trial, HypoBar I will investigate the effectiveness in reducing the risk of PBH, safety, ambulatory glucose profile and entero-endocrine responses when PBH is treated with canagliflozin 300 mg twice daily during a 4-week intervention period, compared with acarbose 50 mg thrice daily or placebo.

ETHICS AND DISSEMINATION

HypoBar I is approved by the Local regulatory entities. Results will be published in peer-reviewed journals.

CONCLUSION

If effective, well-tolerated and safe, canagliflozin could be a novel treatment for people with PBH. HypoBar I might also unravel new mechanisms underlying PBH, potentially identifying new treatment targets.

TRIAL REGISTRATION

EudraCT number 2022-000157-87.