ROCKVILLE, Md.--(BUSINESS WIRE)--Rexahn Pharmaceuticals, Inc. (NYSE Amex: RNN), a clinical stage pharmaceutical company commercializing potential best in class oncology and CNS therapeutics, today announced that the European Patent Office has granted European patent No. 2099765 to Rexahn, entitled “5, 6, or 7-Substituted-3-arylisoquinolinamine derivatives as antitumor agents.”