Off‐Label Use of Exenatide for the Management of Insulin‐Resistant Type 1 Diabetes Mellitus in an Obese Patient with Human Immunodeficiency Virus Infection

Exenatide is an incretin mimetic indicated for the treatment of type 2 diabetes mellitus in combination with a sulfonylurea, a thiazolidinedione, metformin, or metformin plus a sulfonylurea or thiazolidinedione. Exenatide lowers postprandial blood glucose levels by stimulating glucose‐dependent insulin secretion, inhibiting glucagon secretion, slowing gastric emptying, and increasing satiety. Therapy with exenatide often results in weight loss, which further assists in decreasing insulin resistance. This feature makes the drug an attractive therapeutic option for obese patients. We report the successful off‐label use of exenatide in an obese, 40‐year‐old man with type 1 diabetes and human immunodeficiency virus (HIV) infection who had gastrointestinal intolerance to pramlintide. The patient had experienced a dramatic weight gain secondary to his antiretroviral drugs. This weight gain led to insulin resistance and the development of type 2 diabetes; thus he had characteristics of both types 1 and 2 diabetes, or double diabetes. Before the start of exenatide therapy, he weighed 123 kg, had a body mass index of 42.3 kg/m2, and had a suboptimal hemoglobin A1c value of 8.7%. After 11 months of therapy, the patient lost 24 kg (19.5% of his body weight) and achieved a hemoglobin A1c value of 7.3%. His basal insulin requirement was reduced by 25%, and his use of short‐acting insulin before breakfast and before dinner was discontinued. In addition, the patient's quality of life substantially improved, as he was able to return to work and exercise after being nearly incapacitated by his weight. To our knowledge, this is the first published case report of the use of exenatide in a patient with type 1 diabetes mellitus or human immunodeficiency virus infection. Given this experience, exenatide may prove to be a useful alternative in selected patients with type 1 diabetes.