Energy Balance & Weight Loss in Craniopharyngioma-related or Other Hypothalamic Tumors in Hypothalamic Obesity

Excessive weight gain and its cardiometabolic sequela are frequent complications of hypothalamic tumors, a condition known as hypothalamic obesity (HO). Most tumors in this region are craniopharyngiomas (CP),1 which constitute 5-9% of childhood brain tumors. Patients with CP typically become obese and have more features of the metabolic syndrome compared to matched controls. Overall, a 3-19-fold higher cardiovascular mortality had been reported, and a recent nationwide population-based study in Sweden demonstrated increased rates for cerebral infarction (7-fold), death due to cerebrovascular diseases (5-fold), and type 2 diabetes mellitus (6-fold) in CP patients in comparison to the general population. Thus, early and effective management of obesity is vital for this population, which is more resistant to treatment than uncomplicated obesity. Recognized risk factors for severe obesity include large hypothalamic tumors or lesions affecting several medial and posterior hypothalamic nuclei that impact satiety signaling pathways. Structural damage in these nuclei often lead to uncontrolled appetite, rapid weight gain, central insulin and leptin resistance, decreased sympathetic activity, low energy expenditure (EE), and increased energy storage in adipose tissue. Recently, the investigators developed a semi-quantitative assessment of hypothalamic damage on brain magnetic resonance imaging (MRI) to predict the risk for HO development in CP. Previous results of treating HO with a glucagon-like-peptide-1 receptor agonist (GLP1RA) in rats and humans provide promising proof-of-principle data to support this current randomized clinical trial. The primary hypothesis of this study is that drugs causing weight loss via intact hindbrain signaling pathways offer a desperately needed option for treatment of HO, even in very obese HO subjects with severe hypothalamic damage. Induction of weight loss by GLP1RAs is believed to be related to multiple mechanisms involving the gastrointestinal tract, vagus nerve, and the brain leading to increased satiety. Peripheral administration of GLP-1 or GLP1RA reduces blood glucose and energy intake in humans and rodents, and long-term treatment results in loss of body weight. Critically, the investigators do not know whether GLP1RA treatment affects EE and activity, or whether the site and size of brain lesions affect responses to GLP1RA treatment. The investigators' previous clinical studies of the GLP1RA exenatide in obese adolescents and adults have generated the critical safety and efficacy data needed to design a clinical trial. In a pilot study conducted at Children's Hospitals and Clinics of MN, pretreatment hyperphagia was associated with BMI reduction. Using these data, the investigators have designed a prospective, multicenter trial that will examine the effects of GLP1RA on BMI, cardiovascular disease (CVD) risk factors, energy homeostasis and other factors in subjects with HO secondary to CP.