A Pilot Randomized Clinical Trial of Intranasal Oxytocin to Promote Weight Loss in Individuals With Hypothalamic Obesity

Abstract

Context Hypothalamic obesity is a rare, treatment-resistant form of obesity. In preliminary studies, the hypothalamic hormone oxytocin (OXT) has shown promise as a potential weight loss therapy. Objective To determine whether 8 weeks of intranasal OXT (vs. 8 weeks of placebo) promotes weight loss in children, adolescents, and young adults with hypothalamic obesity. Design Randomized, double-blind, placebo-controlled, cross-over pilot trial (NCT02849743). Setting Outpatient academic medical center. Participants Aged 10y to 35y, hypothalamic obesity from hypothalamic/pituitary tumors. Intervention Intranasal OXT (Syntocinon, 40 USP units/mL, 4 IU/spray) vs. excipient-matched placebo, 16-24 IU three times daily at mealtimes. Main outcome measure(s) Weight loss attributable to OXT vs. placebo, safety (adverse events). Results Of 13 individuals randomized (54% female, 31% pre-pubertal, median age 15.3y, IQR 13.3-20.6), 10 completed the entire study. We observed a non-significant within-subject weight change of -0.6 kg (95% CI: -2.7, 1.5) attributable to OXT vs. placebo. A subset (2/18 screened, 5/13 randomized) had prolonged QTc interval on electrocardiography (ECG) prior to screening and/or in both treatment conditions. Overall, OXT was well-tolerated, and adverse events (epistaxis and nasal irritation, headache, nausea/vomiting, and changes in heart rate, blood pressure, and QTc interval) were similar between OXT and placebo. In exploratory analyses, benefits of OXT for anxiety and impulsivity were observed. Conclusions In this pilot study in hypothalamic obesity, we did not detect a significant impact of intranasal OXT on body weight. OXT was well-tolerated, so future larger studies could examine different dosing, combination therapies, as well as potential psychosocial benefits.