ROCKVILLE, Md.--(BUSINESS WIRE)--Rexahn Pharmaceuticals, Inc. (NYSE Amex: RNN), a clinical stage pharmaceutical company developing and commercializing potential best in class oncology and CNS therapeutics, today announced that it has submitted an investigational new drug application (IND) to the Food and Drug Administration for a first-in-human study of RX-5902 to treat advanced or metastatic solid tumors. RX-5902 is a first-in-class small molecule that inhibits the phosphorylated p68 RNA helicase, a protein that plays a key role in cancer growth, progression and metastasis. The phosphorylated form of p68 RNA helicase is only present in cancer cells and is absent in normal cells.