Seattle Genetics Announces Proposed Public Offering of Common Stock

BOTHELL, Wash.--(BUSINESS WIRE)--Seattle Genetics, Inc. (Nasdaq: SGEN) announced today that it is offering to sell, subject to market and other conditions, 9,000,000 shares of its common stock pursuant to an effective shelf registration statement in an underwritten public offering. Seattle Genetics also intends to grant the underwriters a 30-day option to purchase up to an aggregate of 1,350,000 additional shares of common stock to cover over-allotments, if any. All of the shares in the offering are to be sold by Seattle Genetics. J.P. Morgan Securities Inc. and Goldman, Sachs & Co. are acting as joint book-running managers of the proposed offering.

A shelf registration statement relating to the shares was filed with the Securities and Exchange Commission and is effective. Information about the offering is available in the preliminary prospectus supplement to be filed with the Securities and Exchange Commission. This press release does not constitute an offer to sell, or the solicitation of an offer to buy, these securities, nor will there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale is not permitted.

Copies of the preliminary prospectus supplement and accompanying prospectus may be obtained by contacting J.P. Morgan Securities Inc., Attention: Prospectus Department, 4 Chase Metrotech Center, CS Level, Brooklyn, NY 11245 or by calling [phone] or Goldman, Sachs & Co., 85 Broad Street, SC Level, New York, New York 10004, Attention: Prospectus Department or by calling [phone].

About Seattle Genetics

Seattle Genetics is a clinical stage biotechnology company focused on the development and commercialization of monoclonal antibody-based therapies for the treatment of cancer and autoimmune disease.

Certain of the statements made in this press release are forward looking, such as those, among others, relating to Seattle Genetics’ expectations regarding the completion, timing and size of the proposed public offering. Actual results or developments may differ materially from those projected or implied in these forward-looking statements. Factors that may cause such a difference include, without limitation, risks and uncertainties related to market conditions and the satisfaction of customary closing conditions related to the proposed public offering. There can be no assurance that Seattle Genetics will be able to complete the proposed public offering on the anticipated terms, or at all. Seattle Genetics will continue to need significant amounts of additional capital to fund its operations and may be unable to raise capital when needed, which would force Seattle Genetics to delay, reduce the scope of or eliminate one or more of its development programs. Additional risks and uncertainties relating to the proposed offering, Seattle Genetics and its business can be found under the heading “Risk Factors” in Seattle Genetics’ Quarterly Report on Form 10-Q for the quarter ended June 30, 2009, and in the preliminary prospectus supplement related to the proposed offering to be filed with the Securities and Exchange Commission on August 10, 2009. Seattle Genetics disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.