Arena’s lead drug candidate, APD356, an appetite suppressant, is an agonist for the 5Ht-2c serotonin receptor. The good news is that there was a huge blockbuster drug with exactly this mechanism. The bad news was that this drug was Phen-Fen. APD356 targets the same 5Ht-2c serotonin receptor targeted by Phen-Fen. -- specifically the ‘Fen’ part of Phen-Fen (fenfluramine and dexfenfluramine).
They should be starting a small phase II by the end of the year.