How REL-1017 (esmethadone) works

The Relight clinical research program is testing an investigational medication for people living with Major Depressive Disorder (MDD).

REL-1017 is an investigational medicine currently under evaluation in Phase III clinical trials in the United States for the treatment of MDD (Major Depressive Disorder). REL-1017 is not currently approved for any condition.

The active ingredient in REL-1017 is esmethadone

REL-1017 interacts with a family of brain receptors called N-methyl-D-aspartate (NMDA) receptors, which are unique and distinct from other brain receptors 1. By interacting with NMDA receptors, REL-1017 may relieve depression 2. The active ingredient in REL-1017 tablets is esmethadone. Esmethadone is also sometimes referred to as dextro-methadone or d-methadone. Opioid effects, such as dissociation, withdrawal symptoms and drug likability, have not been seen with esmethadone.
Brain synapses.

Phase I and II results

The Phase I and Phase II studies of REL-1017 caused no serious adverse events 3,4. One of the purposes of Phase III clinical trials is to evaluate the potential for adverse events.

Human Abuse Potential (HAP) study

A recently completed dedicated study called the Human Abuse Potential (HAP) study showed that REL-1017 does not have addictive potential 5.
Man of color with depression.
The Relight clinical research study is enrolling now
By joining this research study, your participation may help change the future of how doctors treat MDD.
Find a study location

You may be eligible to participate as a volunteer if you:

Are 18-65 years of age
Have been diagnosed with depression (major depressive disorder)
Are currently feeling depressed and are taking an antidepressant  
Bettini E, Stahl SM, De Martin S, et al. Pharmacological Comparative Characterization of REL-1017 (Esmethadone-HCl) and Other NMDAR Channel Blockers in Human Heterodimeric N-Methyl-D-Aspartate Receptors. Pharmaceuticals (Basel). 2022;15(8):997. Published 2022 Aug 13. doi:10.3390/ph15080997
Mathews DC, Henter ID, Zarate CA. Targeting the glutamatergic system to treat major depressive disorder: rationale and progress to date. Drugs. 2012;72(10):1313-1333  
Bernstein G. et al. Characterization of the Safety and Pharmacokinetic Profile of D-Methadone, a Novel N-Methyl-D-Aspartate Receptor Antagonist in Healthy, Opioid-Naive Subjects. J Clin Psychopharmacol. 2019;39: 226-237
Fava et al. Rapid and Sustained Antidepressant Effects of REL-1017 (dextromethadone) as an Adjunctive Treatment for Major Depressive Disorder: A Phase 2 Trial. 2021. Poster presented at: American Psychiatric Association Annual Meeting
Shram MJ, Henningfield JE, Apseloff G, et al. The novel uncompetitive NMDA receptor antagonist esmethadone (REL-1017) has no meaningful abuse potential in recreational drug users. Transl Psychiatry. 2023;13(1):192. Published 2023 Jun 7. doi:10.1038/s41398-023-02473-8