Nelotanserin (former developmental code name APD-125) is a drug developed by Arena Pharmaceuticals which acts as an inverse agonist on the serotonin receptor subtype 5-HT2A and was under development for the treatment of insomnia.

[4] Research continues on newer analogues which may potentially be more successful.

[5] Later, nelotanserin was repurposed for the treatment of Lewy body dementia (LBD) by Axovant Sciences (now Sio Gene Therapies).

[6] In late 2018, the company announced that while nelotanserin was generally well-tolerated by LBD patients in a small Phase 2 clinical trial for the treatment of REM sleep behavior disorder (RBD) and there were positive indications on some secondary trial outcomes such as sleep diaries and some polysomnogram sleep parameters, the drug failed to meet its primary endpoint of reducing the frequency of RBD episodes and would be discontinued.

[7] This drug article relating to the nervous system is a stub.