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Published in: Trials 1/2024

Open Access 01-12-2024 | Mood Disorders | Study protocol

The translocator protein 18kDa ligand etifoxine in the treatment of depressive disorders—a double-blind, randomized, placebo-controlled proof-of-concept study

Authors: Lisa-Marie Brunner, Marco Riebel, Simon Wein, Michael Koller, Florian Zeman, Gunnar Huppertz, Tanja Emmer, Yvonne Eberhardt, Jens Schwarzbach, Rainer Rupprecht, Caroline Nothdurfter

Published in: Trials | Issue 1/2024

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Abstract

Background

Recent developments suggest that neurosteroids may achieve rapid antidepressant effects. As such, neurosteroidogenesis mediated by the translocator protein 18 kDa (TSPO) might constitute a promising option for the treatment of depression. Therefore, the current clinical trial aims to get the first evidence of whether TPSO ligands promote rapid antidepressant effects. Furthermore, we study which mechanisms of action, e.g., modulation of distinct neuronal networks, neurosteroidogenesis, endocrinological mechanisms, TSPO expression or microbiome composition, contribute to their putative antidepressant effects.

Methods

This is a randomized, placebo-controlled, double-blind single-center trial of 2-week treatment with the TSPO ligand etifoxine versus placebo in depressive patients. Main eligibility criteria: male or female individuals aged 18 to 65 years with unipolar/bipolar depressive disorder with no other psychiatric main diagnosis or acute neurological/somatic disorder or drug/alcohol dependence during their lifetime.
The primary endpoint is the time point at which 50% of the maximal effect has occurred (ET50) estimated by the scores of the Hamilton Depression Scale (HAMD-21). A total of 20 patients per group are needed to detect changes of therapeutic efficacy about 5% and changes of ET50 about 10% with a power of 70%. Assuming a drop-out rate of 10–20%, 50 patients will be randomized in total. The study will be conducted at the Department of Psychiatry and Psychotherapy of the University of Regensburg.

Discussion

This study will provide a first proof-of-concept on the potential of the TSPO ligand etifoxine in the treatment of depressive disorders.

Trial registration

Clinical Trials Register (EudraCT number: 2021-006773-38, registration date: 14 September 2022) and German Register of Clinical Studies (DRKS number: DRKS00031099, registration date: 23 January 2023).
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Metadata
Title
The translocator protein 18kDa ligand etifoxine in the treatment of depressive disorders—a double-blind, randomized, placebo-controlled proof-of-concept study
Authors
Lisa-Marie Brunner
Marco Riebel
Simon Wein
Michael Koller
Florian Zeman
Gunnar Huppertz
Tanja Emmer
Yvonne Eberhardt
Jens Schwarzbach
Rainer Rupprecht
Caroline Nothdurfter
Publication date
01-12-2024
Publisher
BioMed Central
Published in
Trials / Issue 1/2024
Electronic ISSN: 1745-6215
DOI
https://doi.org/10.1186/s13063-024-08120-x

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