Arena Pharmaceuticals (ARNA) To File Mixed Securities Shelf

Arena Pharmaceuticals, Inc. (Nasdaq: ARNA) intends to offer shares of its common stock in a public offering. Piper Jaffray & Co. will be the sole underwriter for the offering. The offering is being made pursuant to a shelf registration statement filed with the Securities and Exchange Commission on November 25, 2008, which became effective on December 3, 2008. A prospectus supplement relating to the offering will be filed with the Securities and Exchange Commission.[SM}