Ambrx, Inc., announced today the appointment of Martin A Mattingly, Pharm.D. as President and Chief Executive Officer, effective immediately. Dr. Mattingly will also join the company's board of directors.

"Ambrx has made remarkable progress since its inception 24 months ago to the present point of GMP manufacture of its first drug candidate," said Richard D. DiMarchi, Chairman of the Board at Ambrx. "Management of our rapid growth requires a CEO with strong operating and commercialization experience to lead the company through the next phase."

Dr. Mattingly brings significant experience as a biotechnology and pharmaceutical executive. He was most recently Executive Vice President and Chief Operating Officer at CancerVax. From 1996 to 2003, he provided senior leadership in various management positions at Agouron Pharmaceuticals and Pfizer. These assignments included General Manager for the Agouron division; Vice President, Product Development Group; and Vice President, Global Marketing Planning. From 1983-1996, Dr. Mattingly held various positions in oncology marketing and sales management at Eli Lilly and Company. He holds a Doctorate in Pharmacy from the University of Kentucky.

"Ambrx has the scientific excellence and the talent to significantly impact the future development of protein-based medicines," said Dr. Mattingly. "I am honored to have the opportunity to lead this outstanding team."

About Ambrx
Ambrx is a biopharmaceutical company committed to transforming the science and performance of protein-based medicines. Building on a fundamental advance in protein biosynthesis, Ambrx can genetically engineer proteins with novel amino acid building blocks beyond the common twenty. This approach represents a new paradigm in protein engineering and permits the pharmaceutical optimization of proteins in a manner analogous to that used for decades to improve the properties of traditional small molecule-based drugs and peptides. The company's most advanced product candidate, a human growth hormone with superior performance, is currently in preclinical development with an IND filing anticipated in 2006. In addition, Ambrx is optimizing several other protein therapeutics representing large markets and significant unmet medical need.

For more information, please contact Troy Wilson, Ambrx's Chief Business Officer, at (858) 875-2505 or visit the company's website at www.ambrx.com.