Bothell, WA-based Marina Biotech (NASDAQ: MRNA), the developer of RNA interference treatments, said today it has raised gross proceeds of $6.9 million through a stock offering. The company sold 22.3 million securities units, made up of one share of common stock and one warrant to buy a share of common stock. Marina has said it plans to use the money to support clinical development of its drug for familial adenomatous polyposis. Roth Capital Partners managed the offering. Marina has said it had about $2.3 million in cash on hand at the end of March.