Saber Bioscience Licenses Technology to Develop Optimized, Fully Human Antibodies

Seattle, Washington – January 14, 2013 – sAber™ Bioscience Corporation announced today that it has licensed the use of the XmAb® Fv technology platform from Xencor, Inc. for the optimization of antibody drug candidates. Under the agreement, sAber will gain access to the technology for the optimization of antibodies derived from non-murine sources. This technology will allow sAber to rapidly build an internal pipeline of fully human therapeutic antibodies as well as to provide contract discovery services to customers in the Biotech and Pharma industry. Said Xencor CEO Bassil Dahiyat, “I’m enthusiastic about sAber’s plans and their ability to push this technology into new areas of antibody discovery and optimization”.

A Proven Technology for Generating Fully Human Antibodies

Humanization is the protein engineering process used to make antibodies isolated from immunized non- human hosts compatible with the human immune system. XmAb variable region optimization uses a novel and proprietary method for humanizing antibodies called “human re-stringing” and is one of the only engineering methods proven capable of generating “fully human” antibodies. This computation- based method scans the entire naturally-occurring repertoire of human antibody sequences to find the components that best match the structure of the starting antibody. The robust computational algorithm eliminates laborious modeling steps from the humanization process and enables the parallel engineering of many antibodies. The XmAb approach provides simultaneous optimization of affinity and physical properties while facilitating the creation of fully human antibodies indistinguishable from those derived from display techniques or transgenic mice. Xencor’s entire XmAb pipeline has been created using this tool, including clinically tested antibodies XmAb®2513, XmAb®5574, and XmAb®5871. Antibodies from the native immune repertoire of an immunized host have the inherent advantage of innate optimization mechanisms including somatic mutagenesis for high affinity and negative selection for high specificity. Because each species has its own unique antigen processing machinery and accompanying antibody repertoire, each will generate antibodies with correspondingly unique antigen recognition. The use of an immunized host simplifies the generation of antibodies to both complex and difficult-to-express antigens. Additionally, the use of nonmurine species bypasses the confounding issue of murine host tolerance, thereby maximizing the potential for finding antibodies that both bind human targets and are testable in murine disease models.

About sAber Bioscience Corporation

sAber Bioscience is developing its AnthropImmune™ antibody discovery platform to extend the range of immunized hosts from which fully human antibodies are derived. sAber is tapping into an extensive new source of antibody diversity for therapeutics discovery. Nonmurine host species, commonly rabbit and goat, are widely used to make outstanding antibodies for research applications. However, inherent limitations have thus far restricted their use for therapeutic antibody discovery. sAber is pairing two rapid and robust methodologies to bypass these limitations and efficiently create novel antibodies for therapeutic indications. sAber uses its proprietary Ig-Access™ technology to query the B-cell repertoire of immunized hosts without the need for cumbersome hybridoma formation. sAber then applies its In Silico Transgenics™ method (incorporating the XmAb Fv technology licensed from Xencor) to generate fully human antibodies. sAber Bioscience founder and CEO Phil Hammond, PhD, was formerly Associate Director of Protein Engineering at Xencor and has over 25 years of experience in Biotechnology. This experience includes key roles in the progression of several biotherapeutics from the lab to the clinic. For more information please visit www.saberbio.com.

sAber Bioscience Contact:

Phil Hammond, Ph.D.

President and CEO

sAber Bioscience

Tel: 425-405-5016

phil@saberbio.com