Under an agreement announced in January 2007, Wyeth has the option to obtain an exclusive license to develop and commercialize selected MAbs from Raven’s portfolio of antibodies to a specified target

SOUTH SAN FRANCISCO, CA, USA | December 6, 2007 | Raven biotechnologies, inc., a privately held company focused on the development of monoclonal antibody therapeutics (MAbs) for cancer, today announced that Wyeth Pharmaceuticals, a division of Wyeth (NYSE: WYE), has exercised an option to extend its evaluation of selected Raven MAb antibodies. As a result, Raven will receive an undisclosed milestone payment.

Under an agreement announced in January 2007, Wyeth has the option to obtain an exclusive license to develop and commercialize selected MAbs from Raven’s portfolio of antibodies to a specified target.

The antibodies included in the agreement were discovered using Raven proprietary immunization technology and tumor-derived stem-cell lines and were screened to select antibodies that are active alone or in a conjugated form.

“We look forward to continuing our agreement with Wyeth, a company with a strong commitment to oncology research and development,” said George F. Schreiner, M.D., Ph.D., Raven’s Chief Executive Officer. “Raven has multiple anti-cancer antibody drug candidates in our pipeline, and collaborations such as this are a critical part of our strategy to rapidly advance the most promising candidates into the clinic.”

About Raven

Raven biotechnologies, inc. (www.ravenbio.com) is a privately held biotechnology company focused on the development of monoclonal antibody therapeutics for treating cancer. Raven’s lead product candidate, RAV12, targets adenocarcinomas and is in clinical development for the treatment of gastrointestinal and other cancers. Raven’s discovery process simultaneously identifies cell-surface drug targets and the antibody therapeutics to regulate them. Our focus on biological function allows us to rapidly identify novel target antigens and therapeutic candidates in their native configuration in the intact cell membrane. Our integrated approach is based on proprietary methods for optimizing the production of MAbs targeting cell-surface proteins, including the use of human tissue-specific progenitor and tumor stem cell lines developed at Raven.

To date Raven has identified multiple candidate therapeutic MAbs for many cancer indications including lung, colon, pancreatic, prostate, breast, and ovarian cancer.

On November 12, 2007, Raven and VaxGen Inc. (Pink Sheets: VXGN.PK), a biopharmaceutical company, announced that their respective boards of directors unanimously approved a definitive merger agreement. The merger is expected to create a drug development company with a robust pipeline of monoclonal antibody candidates in oncology, proprietary antibody discovery platforms, biopharmaceutical manufacturing capabilities and sufficient cash to fund operations at least through the end of 2009. The merger is expected to close in the first half of 2008.

SOURCE: RAVEN BIOTECHNOLOGIES, INC.