Zelquistinel
Zelquistinel is an orally active small-molecule NMDA receptor modulator which is under development for the treatment of major depressive disorder by Syndeio Biosciences, and previously by Allergan.
Pharmacology
Zelquistinel acts through a unique binding site on the NMDA receptor, independent of the glycine site, to modulate receptor activity and enhance NMDAR-mediated synaptic plasticity. Its mechanism of action is similar to that of rapastinel. However, unlike rapastinel, zelquistinel is orally bioavailable, exhibits increased potency, and has improved drug properties. The mean half-life of Zelquistinel is reported to be from 1.21 to 2.06 hours, reaching peak plasma concentrations 30 minutes after administration.In preclinical studies, single doses of zelquistinel demonstrated both rapid-acting and sustained antidepressant-like effects and enhancement of long-term synaptic plasticity.
Clinical development
On July 23, 2018, the U.S. FDA granted Fast Track designation to the development of zelquistinel as an investigational new treatment for major depressive disorder.In 2019, Allergan completed an exploratory phase IIa clinical trial of once-weekly oral zelquistinel in major depressive disorder. By week three, the two highest doses studied reduced MADRS depression scores by 9.5 and 10.6 points compared to a 7.7-point reduction with placebo. This result was considered statistically and clinically significant.
As of 2025, zelquistinel is undergoing a phase IIb clinical trial for depression sponsored by Syndeio Biosciences.