Seattle Geneticsannounced today that it has initiated a phase I clinical trial of SGN-70, a humanized monoclonal antibody targeting CD70 that is being developed as an investigational therapy for autoimmune diseases

BOTHELL, WA, USA | July 31, 2008 | Seattle Genetics, Inc. (Nasdaq:SGEN) announced today that it has initiated a phase I clinical trial of SGN-70, a humanized monoclonal antibody targeting CD70 that is being developed as an investigational therapy for autoimmune diseases. The trial will assess the safety, tolerability and pharmacokinetics of SGN-70 in healthy volunteers.

"CD70 targeted therapies have shown promise in multiple preclinical models by reducing autoimmune disease activity at well-tolerated doses," said Thomas C. Reynolds, M.D., Ph.D., Chief Medical Officer of Seattle Genetics. "This clinical trial is designed to evaluate the safety and pharmacokinetics of SGN-70 in humans and to serve as a foundation for future clinical trials in patients with autoimmune disease."

The phase I study is a dose-escalation trial in which cohorts of healthy volunteers will receive single doses of SGN-70. The clinical trial will be conducted in Switzerland and is expected to accrue approximately 60 volunteers.

The CD70 antigen is highly expressed on activated T- and B-cells but not resting lymphocytes, and has been associated with a variety of autoimmune and inflammatory disorders. SGN-70 has been shown in preclinical models to selectively deplete CD70-positive lymphocytes and block the co-stimulation pathway between CD70 and its receptor, CD27. By specifically targeting the activated cells, SGN-70 may reduce the damaging effects of autoimmune disease without globally suppressing the immune system.

CD70 is also expressed on several types of cancer, including multiple myeloma, lymphoma, renal cell cancer, glioblastoma and several other solid tumors. In addition to SGN-70, Seattle Genetics is advancing SGN-75, an antibody-drug conjugate targeting CD70, for the treatment of cancer and expects to file an investigational new drug (IND) application in 2009.

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. The company has a worldwide collaboration with Genentech for SGN-40. Seattle Genetics also has two other product candidates in ongoing clinical trials: SGN-33 and SGN-35. In addition, the company has developed proprietary antibody-drug conjugate (ADC) technology comprising highly potent synthetic drugs and stable linkers for attaching the drugs to monoclonal antibodies. Seattle Genetics has collaborations for its ADC technology with a number of leading biotechnology and pharmaceutical companies, including Genentech, Bayer, CuraGen, Progenics, Daiichi Sankyo and MedImmune, a wholly-owned subsidiary of AstraZeneca, as well as an ADC co-development agreement with Agensys, a wholly-owned subsidiary of Astellas Pharma.

Certain of the statements made in this press release are forward looking, such as those, among others, relating to the therapeutic potential of SGN-70. 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 the inability to show sufficient safety in this phase I clinical trial and the risk of adverse clinical results as SGN-70 moves into and advances in clinical trials. More information about the risks and uncertainties faced by Seattle Genetics is contained in the Company’s filings with the Securities and Exchange Commission. 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.

SOURCE: Seattle Genetics