Remlifanserin
Remlifanserin is a selective serotonin 5-HT2A receptor inverse agonist which is under development for the treatment of Alzheimer's disease psychosis. It is taken by mouth.
The drug is an improved follow-up compound to its developer's earlier drug pimavanserin. It is more potent and selective than pimavanserin as a serotonin 5-HT2A receptor inverse agonist. Remlifanserin shows 32- to 123-fold selectivity for antagonism and inverse agonism of the serotonin 5-HT2A receptor over the serotonin 5-HT2C receptor depending on the bioassay. For comparison, pimavanserin's selectivity was 8- to 37-fold depending on the assay. Remlifanserin shows very low affinity for the serotonin 5-HT2B receptor compared to the serotonin 5-HT2A and 5-HT2C receptors. It is expected to have less QT prolongation than pimavanserin. The drug blocks the head-twitch response induced by the serotonergic psychedelic DOI and the hyperlocomotion induced by the NMDA receptor antagonist dizocilpine in rodents.
Remlifanserin is under development by Acadia Pharmaceuticals. As of January 2025, it is in phase 3 clinical trials. Its clinicaltrials.gov identifier is NCT06159673.