NYX-2925, A Novel N-methyl-D-aspartate Receptor Modulator: A First-in-Human, Randomized, Double-blind Study of Safety and Pharmacokinetics in Adults.

NYX-2925, a new chemical entity, acts as a co-agonist to glutamate at the N-methyl-D-aspartate receptor (NMDAR). At low concentrations of endogenous agonists (glycine/D-serine), NYX-2925 partially activates NMDARs, modulating neural pathways relevant for chronic pain. NYX-2925 is being developed for the treatment of chronic pain conditions, including painful diabetic peripheral neuropathy and fibromyalgia. In this first-in-human, phase I, single-ascending dose (50-1,200 mg) and multiple-ascending dose (150-900 mg) study, the safety, tolerability, and pharmacokinetics (PKs) of NYX-2925 were evaluated in 84 healthy adult volunteers. No safety concerns emerged, including no dissociative side effects. NYX-2925 exhibited dose-proportional PKs and minimal accumulation following once-daily dosing for 7 days. Cerebrospinal fluid (CSF) measurements confirmed that NYX-2925 crosses the blood brain barrier, with maximum CSF concentrations approximating 6-9% of maximum plasma concentrations at the same dose level. NYX-2925 was safe and well-tolerated in healthy volunteers, and the study results support the continued clinical development for chronic pain conditions.

NYX-2925 Is a Novel NMDA Receptor-Specific Spirocyclic-ß-Lactam That Modulates Synaptic Plasticity Processes Associated with Learning and Memory.

Background: N-methyl-D-aspartate receptors are one member of a family of ionotropic glutamate receptors that play a pivotal role in synaptic plasticity processes associated with learning and have become attractive therapeutic targets for diseases such as depression, anxiety, schizophrenia, and neuropathic pain. NYX-2925 ((2S, 3R)-3-hydroxy-2-((R)-5-isobutyryl-1-oxo-2,5-diazaspiro[3.4]octan-2-yl)butanamide) is one member of a spiro-ß-lactam-based chemical platform that mimics some of the dipyrrolidine structural features of rapastinel (formerly GLYX-13: threonine-proline-proline-threonine) and is distinct from known N-methyl-D-aspartate receptor agonists or antagonists such as D-cycloserine, ketamine, MK-801, kynurenic acid, or ifenprodil. Methods: The in vitro and in vivo pharmacological properties of NYX-2925 were examined. Results: NYX-2925 has a low potential for "off-target" activity, as it did not exhibit any significant affinity for a large panel of neuroactive receptors, including hERG receptors. NYX-2925 increased MK-801 binding to human N-methyl-D-aspartate receptor NR2A-D subtypes expressed in HEK cells and enhanced N-methyl-D-aspartate receptor current and long-term potentiation (LTP) in rat hippocampal slices (100-500 nM). Single dose ex vivo studies showed increased metaplasticity in a hippocampal LTP paradigm and structural plasticity 24 hours after administration (1 mg/kg p.o.). Significant learning enhancement in both novel object recognition and positive emotional learning paradigms were observed (0.01-1 mg/kg p.o.), and these effects were blocked by the N-methyl-D-aspartate receptor antagonist CPP. NYX-2925 does not show any addictive or sedative/ataxic side effects and has a therapeutic index of >1000. NYX-2925 (1 mg/kg p.o.) has a cerebrospinal fluid half-life of 1.2 hours with a Cmax of 44 nM at 1 hour. Conclusions: NYX-2925, like rapastinel, activates an NMDA receptor-mediated synaptic plasticity process and may have therapeutic potential for a variety of NMDA receptor-mediated central nervous system disorders.