Revenues in the third quarter of 2009 were $11.6 million, compared to $8.1 million in the third quarter of 2008. For the first nine months of 2009, revenues were $30.2 million, up from $25.2 million in the first nine months of 2008. Revenues are primarily driven by the earned portion of the upfront fee, reimbursements and milestone payments received under the company ™s dacetuzumab collaboration with Genentech. Revenues also reflect amounts earned under the company ™s ADC collaborations.

Total operating expenses for the third quarter of 2009 were $32.2 million, compared to $31.4 million for the third quarter of 2008. For the first nine months of 2009, total operating expenses were $102.4 million, compared to $85.1 million in the first nine months of 2008. The planned increases in 2009 were primarily driven by clinical development and manufacturing activities for brentuximab vedotin. Non-cash, share-based compensation expense for the first nine months of 2009 was $8.5 million, compared to $7.4 million for the same period in 2008.

Net loss for the third quarter of 2009 was $19.8 million, or $0.21 per share, compared to $21.8 million, or $0.27 per share, for the third quarter of 2008. For the nine months ended September 30, 2009, net loss was $69.6 million, or $0.79 per share, compared to $54.9 million, or $0.70 per share, for the same period in 2008.

As of September 30, 2009, Seattle Genetics had $306.0 million in cash and investments, compared to $189.9 million as of June 30, 2009. Cash and investments as of September 30, 2009 reflect net proceeds of approximately $128 million from the company ™s public offering of common stock in August 2009. Seattle Genetics anticipates ending 2009 with approximately $270 million in cash and investments. This is based on the company ™s expectation that cash used in operating activities will be at the low end of its previous estimate of $80 million to $90 million.

Conference Call Details

Seattle Genetics ™ management will host a conference call and webcast to discuss the financial results and provide an update on business activities. The event will be held today at 2:00 p.m. Pacific Time (PT); 5:00 p.m. Eastern Time (ET). The live event will be available from Seattle Genetics ™ website at www.seattlegenetics, under the Investors and News section, or by calling (800) 762-8908 (domestic) or (480) 629-9774 (international). The access code is 4172548. A replay of the discussion will be available beginning at approximately 4:00 p.m. PT today from Seattle Genetics ™ website or by calling (800) 406-7325 (domestic) or (303) 590-3030 (international), using access code 4172548. The telephone replay will be available until 4:00 p.m. PT on October 26, 2009.

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