MONROVIA, Calif., and MELBOURNE, Australia, April 16, 2013—Xencor, Inc. announced today that Xencor and CSL Limited have entered into a technology license agreement to provide CSL access to Xencor's Xtend™ technology to optimize the performance of CSL's monoclonal antibodies.

Under the agreement CSL will be granted an exclusive license to utilize Xencor's proprietary Xtend™ half-life extension technology in its program against an undisclosed target. Xencor will receive an upfront payment and is eligible to receive from CSL preclinical, clinical, regulatory and sales milestone payments, as well as royalties on product sales.

"CSL's selection of Xencor's technology reflects the significant interest we have seen in the use of our Xtend™ platform for enhancing next-generation protein and antibody drug candidates," said Bassil Dahiyat, Ph.D., Xencor's chief executive officer. "This technology offers our partners an opportunity to create truly best-in-class therapeutics."

Xencor's Xtend™ technology dramatically improves the pharmacokinetic profile of protein drug candidates while introducing only very subtle changes to the protein sequence.

"Incorporating Xencor's Xtend™ technology into CSL's drug development aligns with our approach of applying breakthrough science to the development of therapeutics for life-threatening conditions," said Andrew Nash, Ph.D., senior vice president of research of CSL. "We are committed to developing the highest quality treatments for the patients who need them."

About Xtend™ technology
Xencor's proprietary antibody technology platform provides a validated solution to enhancing the serum half-life of immunoglobulin molecules. Using its proprietary series of antibody Fc variants, antibody half-life can be readily prolonged to enhance performance in a number of different therapeutic indications. By prolonging the serum half-life of antibody drug molecules the opportunity arises to address chronic indications with an antibody drug product that potentially i) enhances drug exposure and patient responses, ii) is administered at more than monthly intervals, greatly enhancing patient convenience, reducing administration costs and improving market positioning, and iii) has a reduced dose required to maintain effective drug levels, potentially improving the cost, profitability and capital expense profile of the product.

About Xencor, Inc.
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 in the clinic, including XmAb®5871 targeting CD32b and CD19 for autoimmune diseases, and an anti-CD30 candidate XmAb®2513 for the treatment of Hodgkin's lymphoma. Xencor is also advancing a portfolio of biosuperior versions of blockbuster antibody drugs engineered for superior half-life and dosing schedule. Xencor has entered into multiple partnerships with industry leaders such as Amgen, Pfizer, Janssen R&D LLC, MorphoSys, Boehringer Ingelheim, CSL Ltd. and Human Genome Sciences. In these partnerships Xencor is applying its suite of proprietary antibody Fc domains to improve antibody drug candidates for traits such as sustained half-life and/or potency. For more information, please visit www.xencor.com

About CSL
Headquartered in Melbourne, Australia, CSL Limited is a global biopharmaceutical company that develops, manufactures and markets biotherapies to prevent and treat rare and serious human diseases. With major facilities in Australia, Germany, Switzerland and the US, CSL employs over 11,000 people in more than 27 countries. For more information visit www.csl.com.au

Xencor Media Contact
Heidi Chokeir, Ph.D.
Canale Communications for Xencor
Tel: 619-849-5377
heidi@canalecomm.com