SOUTH SAN FRANCISCO, Calif., May 25, 2011 /PRNewswire/ -- Rigel Pharmaceuticals, Inc. (Nasdaq: RIGL), today announced that it intends to offer and sell shares of its common stock in an underwritten public offering. All of the shares in the offering are to be sold by Rigel. The offering is subject to market and other conditions, and there can be no assurance as to whether or when the offering may be completed, or as to the actual size or terms of the offering. Jefferies & Company, Inc. and J.P. Morgan Securities LLC are acting as joint book-running managers for the proposed offering, with Piper Jaffray & Co. acting as co-manager. A shelf registration statement on Form S-3 relating to the public offering of the shares of common stock described above was filed with the Securities and Exchange Commission (the "SEC") and is effective. A preliminary prospectus supplement relating to the offering will be filed with the SEC and will be available on the SEC's website at www.sec.gov. When available, copies of the preliminary prospectus supplement may also be obtained from the offices of Jefferies & Company, Inc., Equity Syndicate Prospectus Department, at 520 Madison Avenue, New York, NY 10022 (Telephone number 877-547-6340) or the offices of J.P. Morgan Securities LLC, c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717 (Telephone number 866-803-9204). This press release shall not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such state or other jurisdiction.