A Randomized Dose-Ranging Study of Neuropeptide Y in Patients with Posttraumatic Stress Disorder

Abstract

Background

Anxiety and trauma-related disorders are among the most prevalent and disabling medical conditions in the United States, and posttraumatic stress disorder in particular exacts a tremendous public health toll. We examined the tolerability and anxiolytic efficacy of neuropeptide Y administered via an intranasal route in patients with posttraumatic stress disorder.

Methods

Twenty-six individuals were randomized in a cross-over, single ascending dose study into 1 of 5 cohorts: 1.4 mg (n=3), 2.8 mg (n=6), 4.6 mg (n=5), 6.8 mg (n=6), and 9.6 mg (n=6). Each individual was dosed with neuropeptide Y or placebo on separate treatment days 1 week apart in random order under double-blind conditions. Assessments were conducted at baseline and following a trauma script symptom provocation procedure subsequent to dosing. Occurrence of adverse events represented the primary tolerability outcome. The difference between treatment conditions on anxiety as measured by the Beck Anxiety Inventory and the State-Trait Anxiety Inventory immediately following the trauma script represented efficacy outcomes.

Results

Twenty-four individuals completed both treatment days. Neuropeptide Y was well tolerated up to and including the highest dose. There was a significant interaction between treatment and dose; higher doses of neuropeptide Y were associated with a greater treatment effect, favoring neuropeptide Y over placebo on Beck Anxiety Inventory score (F _1,20=4.95, P=.038). There was no significant interaction for State-Trait Anxiety Inventory score.

Conclusions

Our study suggests that a single dose of neuropeptide Y is well tolerated up to 9.6 mg and may be associated with anxiolytic effects. Future studies exploring the safety and efficacy of neuropeptide Y in stress-related disorders are warranted.

The reported study is registered at: http://clinicaltrials.gov (ID: NCT01533519).

Abstract

Significance StatementAnxiety and trauma-related disorders are among the most prevalent medical conditions in the United States. Posttraumatic stress disorder (PTSD) in particular is a debilitating disorder that develops in a subset of individuals exposed to extreme stress. Drug discovery for PTSD and anxiety disorders has been largely stagnant, contributing to a substantial disease burden and continued patient suffering. A large body of evidence implicates neuropeptide Y (NPY) in the regulation of stress-related behaviors, and preclinical data suggest that enhancing NPY signaling may reduce anxiety and symptoms of PTSD. Herein, we conducted phase Ib double-blind, randomized, placebo-controlled, dose-ranging study of intranasal administration of NPY in subjects with PTSD. We found that NPY was well tolerated at all tested doses and that high, but not low, doses of NPY were associated with reduced anxiety on some measures. The NPY system may represent a promising target for treatment development for anxiety and trauma-related disorders.