Kymab Announces Milestone in Kymouse™ Human Antibody Platform

Cambridge, UK, 30 March 2012. Kymab, a monoclonal antibody biopharmaceutical company, announced today at the Gordon Research Conference “Antibody Biology and Engineering”, a milestone in the development of its next-generation human therapeutic antibody discovery platform, Kymouse. Dr Glenn Friedrich, Senior VP Technology, presented data showing that a complement of variable regions from the human immunoglobulin heavy chain, kappa and lambda light chains have been successfully established in mouse strains using proprietary ES cell targeted insertion technology. This results in human-like functionality and usage and provides the genetic basis for the company’s first commercial strains, Kymouse HK and Kymouse HL.

“We have substantially completed the genetic construction of the core elements of our Kymouse HK and HL strains,which we plan to use for internal drug discovery and will make available topartners,” said Dr. Friedrich. The data presented at the conference showed that mice with chimaeric human-mouse heavy chain and light chain loci produce normal immunoglobulin levels, with a normal and functional B-cell compartment. These transgenic mice respond to antigen challenges with appropriate class switching. The chimeric human antibodies are matured in vivo through normal somatic hypermutation and affinity maturation processes.

Professor Allan Bradley, Founder and Chief Scientific Officer of Kymab, added, “This represents a major milestone for our Kymouse programme. We have transferred more than two million base pairs of human DNA into mice and shown that human Ig heavy chain, kappa and lambda light chains, are fully functional in Kymousestrains, with background mouse Ig expression being effectively silenced using our proprietary locus inversion technology.”

Andy Sandham, Chairman and CEO said, “This is a remarkable achievement in the field of ES cell and mouse biology. We are now gearing up our internal antibody discovery and partnering activities that will use the Kymouse HK strain this year, with Kymouse HL and other strains planned for launch in early 2013. We believe the Kymouse platform will offer the largest human antibody repertoire to become commercially available in transgenic mice”.

About Kymab

Kymab was founded in 2009 based on research in the field of human immunology and mouse biology at the WellcomeTrust Sanger Institute in the laboratory of Professor Allan Bradley. The company is using mouse embryonic stem cell technology to develop its Kymouse platform, which will encompass the entire diversity of the B lymphocyte component of the human immune system, and has the potential for expansion of diversity beyond the normal human immune response. Kymab will use the Kymouse platform for the discovery, development and commercialisation of antibody-based medicines. Kymab is also seeking to partner the Kymouse platform with the pharmaceutical industry.

Kymab, Kymouse, Kymouse HK and Kymouse HL are trademarks of Kymab Limited.

Contact:

Dr. Tom Shepherd, Chief Business Officer

tom.shepherd@kymab.com

+44 (0) 1223 833301