ROCKVILLE, Md.--(BUSINESS WIRE)--Rexahn (OTCBB:RXHN.OB), a clinical stage biopharmaceutical company dedicated to the discovery, development, and commercialization of innovative treatments for cancer and disorders of the central nervous system (CNS), announced today that a European patent (EP 1206261) has been granted for the treatment of behavioral diseases with its leading CNS drug candidate, RX-10100.