The Food and Drug Administration (FDA) has granted Fast Track designation to REL-1017 (esmethadone) as a monotherapy for the treatment of major depressive disorder (MDD).

REL-1017 is a novel N-methyl-D-aspartate receptor (NMDAR) channel blocker. The investigational treatment is administered orally once daily and is designed to target hyperactive GluN1-GluN2D NMDAR channels while maintaining physiological glutamatergic neurotransmission.

The designation is supported by data from a phase 2 study ( Identifier: NCT03051256), which demonstrated that treatment with REL-1017 produced rapid, robust, and sustained antidepressant effects in patients with MDD compared with placebo. The safety profile of REL-1017 was found to be comparable to placebo, with no opioid, dissociative or psychotomimetic symptoms or withdrawal effects observed upon treatment discontinuation.

REL-1017 is currently being evaluated for the treatment of MDD as monotherapy in the phase 3 RELIANCE-III trial ( Identifier: NCT05081167) and as adjunctive therapy in the phase 3 RELIANCE-I ( Identifier: NCT04688164) and RELIANCE-II ( Identifier: NCT04855747) trials. RELIANCE-OLS, an open-label safety study ( Identifier: NCT04855760), will include participants from all 3 pivotal studies and will evaluate long-term effects.

“The receipt of Fast Track Designation represents a significant milestone for our promising late-stage REL-1017 development program,” said Paolo Manfredi, our CSO. “This designation further supports the potential of REL-1017 as a paradigm shifting novel stand-alone treatment for MDD and highlights the significant unmet medical need in a therapeutic area where little has changed over the last several decades: available treatments remain inadequate for the majority of patients with MDD.”


  1. Relmada Therapeutics receives FDA Fast Track designation for REL-1017 as a monotherapy for the treatment of major depressive disorder. News release. Relmada Therapeutics, Inc. Accessed August 9, 2022.
  2. Relmada Therapeutics announces publication of REL-1017 phase 2 study results in The American Journal of Psychiatry. News release. Relmada Therapeutics, Inc. December 22, 2021. Accessed August 9, 2022.