Monrovia, CA – March 11, 2002 – Xencor today announced that it has exclusively licensed a patent from the Johns Hopkins University School of Medicine (US #6,190,856 B1) entitled, “Methods of Detection Utilizing Modified Bacteriophage,“ expanding the Company’s patent estate for its proprietary chemical genomics platform, ProCode^™. By connecting drug molecules to the genes they act upon, the ProCode^™ technology relieves a critical bottleneck in the drug discovery process and creates the opportunity for safer drugs as well as novel drug and target classes, according to Bassil Dahiyat, Ph.D., president and chief executive officer of Xencor.

“Our ProCode^™ technology allows for the rapid and exquisitely sensitive profiling of drug interactions within the proteome,“ Dr. Dahiyat said. “This patent is a valuable complement to our ProCode^™ capabilities as the patent covers rapid and flexible methods for the detection and isolation of cell membrane receptors in mammalian cells. These techniques impact many drug discovery applications including therapeutic antibody discovery, cell based assays and tissue profiling.“

Xencor’s ProCode^™ technology enables the field of chemical genomics by connecting drug molecules to the genes they act upon. The patent filings covering ProCode^™ were exclusively licensed from the Johns Hopkins University School of Medicine, and are the foundation of Xencor’s patent portfolio in the field of chemical genomics and target discovery. The technology allows the profiling of binding interactions of small molecule drugs with a cell’s proteins in a pharmaceutically relevant environment, accelerating the discovery of new therapeutic products.

ProCode^™ Technology

ProCode^™ is a chemical genomics tool that enables the use of small molecule compounds as the starting point for target identification and side effect profiling. ProCode^™ creates cDNA expression libraries of soluble DNA-protein complexes, where each expressed protein is covalently linked to its corresponding cDNA. ProCode^™ libraries can incorporate any cDNA libraries and are rapidly created and screened in a pooled format. Thus, by panning for protein binding to a compound of interest and amplifying the tethered DNA, one can carry out repeated rounds of screening to isolate genes encoding proteins that interact with compounds of interest. The direct linkage of expressed proteins (function) to DNA (genotype) eliminates the need for laborious detection and purification technologies such as mass spectrometry and 2-D gels. ProCode^™ technology provides the sensitivity of DNA amplification and detection, a billion-fold improvement over existing methods and a feature that greatly simplifies miniaturization and high throughput automation.

Xencor, a privately held company, is focused on using its cutting edge protein analysis and optimization technologies to accelerate the discovery of therapeutic proteins and novel compounds. With its proprietary ProCode^™ and Protein Design Automation^™ (PDA^™) technologies, Xencor scientists can rapidly determine the interactions and functions of a cell’s entire protein complement, identify proteins of interest, and then optimize key properties of these proteins to fit commercial applications. The use of these technologies alone, or in combination, will accelerate the compound identification and development programs of Xencor’s strategic partners in the pharmaceutical, biotechnology, and agricultural and chemical industries. Further information is available at www.xencor.com.