Xencor Receives U.S. Patent for Monoclonal Antibody Engineering that Extends Duration of Action

MONROVIA, Calif., Jan. 6, 2012 /PRNewswire/ -- Xencor, Inc., a company using its proprietary Protein Design Automation® (PDA) platform technology to engineer next-generation antibodies, announced today that the U.S. Patent and Trademark Office has issued Xencor a broad patent covering optimized monoclonal antibody variants and their application for extending in vivo half-life of antibodies. U.S. Patent 8,088,376 is the latest in Xencor's expanding portfolio of patents covering antibody drug candidates and engineering technology to impart specific therapeutic properties, including antibody-dependent cell cytotoxicity (ADCC), immunomodulation and increased half-life and efficacy.

"The issuance of this new patent covers the key element of Xencor's Xtend half-life prolongation technology and supports the work we are doing in collaboration with pharmaceutical industry partners to incorporate this technology in multiple drug candidates and to develop biosuperior versions of approved antibodies," said Bassil Dahiyat, Ph.D., president and CEO of Xencor. "Our PDA technology platform has enabled Xencor to develop an extensive pipeline of clinical-stage products, and our strong patent portfolio positions the company to be a leader in the development of best-in-class antibody therapeutics."

The patent covers amino acid modifications in the Fc domain, part of the constant region of antibodies that improves serum half-life by 2 to 3 fold over native antibodies. Longer half-lives allows for reduced dosing frequency, lower dosing, and potentially improved tolerability and efficacy.

Xencor's intellectual property portfolio now consists of 47 U.S. and 36 foreign issued patents and numerous pending patents for protein and antibody engineering.

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, an anti-CD30 candidate XmAb®2513 for the treatment of Hodgkin's lymphoma, and is advancing a portfolio of biosuperior antibodies that are versions of blockbuster antibody drugs engineered for superior half-life and dosing schedule. Xencor's antibody engineering technology has been licensed through multiple partnerships with industry leaders such as Pfizer, Centocor, 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 potency. For more information, please visit www.xencor.com.

SOURCE Xencor, Inc.

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