Xencor Appoints Jeffrey V. Ravetch of The Rockefeller University to its Scientific Advisory Board

MONROVIA, Calif.--(Business Wire)--
Xencor, Inc., a company using Fc engineering for the discovery and development
of next-generation antibodies, today announced the addition of Jeffrey Ravetch,
M.D., Ph.D., a leader in the study of Fc receptors for immunological research,
to its Scientific Advisory Board. He is a professor and head of the Leonard
Wagner Laboratory of Molecular Genetics and Immunology at The Rockefeller
University, and joins Richard Lerner, M.D., Professor and President of the
Scripps Research Institute, on Xencor`s advisory board.

"Jeff is the pioneer in the study of Fc receptors, the antibody region that
Xencor`s antibody-enhancing technology and current product development engineer
to optimize antibody function," said Bassil Dahiyat, Ph.D., chief executive
officer of Xencor. "His expertise will provide valuable guidance to our
scientific team as we progress additional antibody candidates into the clinic
and complete our Phase 1 trial with XmAb2513 ."

"The synergy between my research and Xencor`s approach to antibody optimization,
combined with strong preclinical and preliminary Phase 1 data to date, make this
an ideal time to join the advisory board," Dr. Ravetch said. "I look forward to
bringing insights and experience gained from my work with the Fc region to bear
on the advancement of Xencor`s pipeline of enhanced antibodies."

Dr. Ravetch is a leading expert in antibody-mediated effector mechanisms and
immune regulation, and contributed to the discovery of the key mechanisms by
which Fc receptors operate. His current research focuses on the cellular and
molecular mechanisms of how healthy immune cells are made to respond to specific
antibodies and how a dysfunctional immune system attacks the body`s own tissues.
Dr. Ravetch`s prior work led to the cloning and mapping of the first malarial
parasite chromosome, and more recently to the cloning of the first Fc receptor
genes. He was also responsible for discovering how immunoglobulin receptors
mediate antibody-triggered inflammation, and determining the mechanism by which
intravenous immunoglobulin causes immunosuppression.

Dr. Ravetch received his Ph.D. from Rockefeller University, his M.D. from
Cornell University Medical College, and completed his postdoctoral research at
the National Institutes of Health in the Laboratory of Molecular Genetics. He
later joined the faculty at Memorial Sloan-Kettering Cancer Center and Cornell
University Medical College before joining The Rockefeller University.

About Xencor

Xencor, Inc. engineers superior biotherapeutics using its proprietary Protein
Design Automation® technology platform, and is a leader in the field of antibody
Fc engineering to significantly improve antibody potency and half-life. The
company is advancing multiple XmAb® antibody drug candidates into the clinic,
led by anti-CD30 candidate XmAb®2513 in a Phase I clinical trial for the
treatment of Hodgkin lymphoma and anaplastic large cell lymphoma, and anti-CD19
candidate XmAb®5574 in pre-clinical development for the treatment for
non-Hodgkin lymphoma and B-cell leukemia. With multiple partners, such as
industry leaders Merck, Pfizer, CSL Ltd., Boehringer Ingelheim, MedImmune and
Human Genome Sciences, Xencor is applying its suite of proprietary antibody Fc
domains to improve antibody drug candidates for traits such as potency and
sustained half-life. For more information, please visit www.xencor.com.

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

Copyright Business Wire 2009