Monrovia, Calif. – February 9, 2010 – Xencor, Inc., a company using Fc engineering for the discovery and development of next-generation antibodies, announced today the appointment of Edgardo Baracchini, Ph.D., to chief business officer. He brings more than 15 years of transactional experience to Xencor, most recently as senior vice president of business development at Metabasis Therapeutics until its merger with Ligand Pharmaceuticals in 2009.

"Ed's extensive background navigating research and development partnerships will be invaluable to Xencor as we continue to expand the adoption of XmAb® technology and maximize our pipeline assets," said Bassil Dahiyat, Ph.D., chief executive officer of Xencor.

Over the course of his career, Dr. Baracchini has structured and negotiated more than 60 business transactions with multinational and Asian pharmaceutical firms, biotechnology companies and leading universities. Prior to Metabasis, he was vice president of business development at Elitra Pharmaceuticals, director of business development at Agouron Pharmaceuticals, which focused on protein-based drug design, and assistant director of business development at Isis Pharmaceuticals. He earned a Ph.D. in molecular and cell biology from the University of Texas at Dallas and conducted his postdoctoral research at UCSD and The Scripps Research Institute. Dr. Baracchini also earned an M.B.A. from the University of California, Irvine.

"As evidenced by the company's string of partnerships last year, including Merck and Pfizer, Xencor's antibody engineering technology provides a unique offering to partners, particularly at a time when there's increasing competition in biologics," added Dr. Baracchini. "I look forward to working with the Xencor team to further utilization of this broad-based technology."

About Xencor

Xencor, Inc. engineers superior biotherapeutics using its proprietary Protein Design Automation® technology platform, and is a leader in the field of antibody engineering to significantly improve antibody half-life, immune-regulatory function and potency. The company is advancing multiple XmAb® antibody drug candidates into the clinic, including XmAb®5871 targeting CD32b and CD19 for autoimmune diseases, a portfolio of biosuperior antibodies that are versions of blockbuster antibody drugs engineered for superior half-life and dosing schedule, and an anti-CD30 candidate XmAb®2513 in a Phase I clinical trial for the treatment of Hodgkin lymphoma. With multiple partners, such as industry leaders Merck, Pfizer, CSL Ltd., Boehringer Ingelheim, MedImmune, Centocor and Human Genome Sciences, Xencor is applying its suite of proprietary antibody Fc domains to improve antibody drug candidates for traits such as sustained half-life and potency. For more information, please visit www.xencor.com.

Contact
Kim Richards
Porter Novelli Life Sciences for Xencor
619-849-5377
krichards@pnlifesciences.com