Publication Date

9-1-2025

Journal

Journal of Clinical Psychopharmacology

DOI

10.1097/JCP.0000000000002046

PMID

40719142

PMCID

PMC12379779

PubMedCentral® Posted Date

7-28-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Background: Anhedonia is a core symptom of major depressive disorder (MDD) that may result from aberrant lateral habenula hyperactivity. Targeting G-protein coupled receptor 139 (GPR139) may improve anhedonia by modulating lateral habenula activity. NBI-1065846 is an investigational GPR139 agonist that improved anhedonia, anxiety, and depression in rodent models.

Methods: TERPSIS was a phase 2, proof-of-concept clinical study. Adults with MDD experiencing a major depressive episode with anhedonia were randomized 1:1 to NBI-1065846 or placebo for 8 weeks. The primary endpoint was the change in the Dimensional Anhedonia Rating Scale (DARS) score. Secondary endpoints were change in total Montgomery Åsberg Depression Rating Scale (MADRS) score in participants with a baseline 17-item Hamilton Depression Rating Scale (HAM-D17) score of ≥19 (moderate to severe) and change in Clinical Global Impression of Severity (CGI-S) score. All changes were from baseline to Day 57.

Results: In total, 93 participants received study treatment (NBI-1065846, n = 46; placebo, n = 47). Both groups showed notable improvements in DARS scores from baseline to day 57 (least-squares mean change: NBI-1065846, 13.5; placebo, 17.4), with no statistically significant difference (NBI-1065846 vs. placebo, P = 0.8663). Similarly, MADRS ( P = 0.7008) and CGI-S ( P = 0.9051) scores showed no significant difference between groups. All treatment-emergent adverse events in the NBI-1065846 group were mild or moderate in severity.

Conclusions: The TERPSIS study did not meet its primary or secondary endpoints. NBI-1065846 was generally well tolerated. Addressing the lack of treatment options for anhedonia remains an important unmet clinical need.

Keywords

Humans, Depressive Disorder, Major, Male, Female, Adult, Anhedonia, Middle Aged, Double-Blind Method, Proof of Concept Study, Psychiatric Status Rating Scales, Young Adult, Acetamides, Triazines, anhedonia, major depressive disorder, dimensional anhedonia rating scale, GPR139 agonist, NBI-1065846

Published Open-Access

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