SUPPLEMENT TO PROXY STATEMENT FOR
THE 2023 ANNUAL GENERAL MEETING OF SHAREHOLDERS
TO BE
HELD ON JUNE 7, 2023
AMBRX BIOPHARMA INC.
10975 North Torrey Pines Road
La
Jolla, California 92037
May 18, 2023
Dear Ambrx Shareholder:
The proxy statement
for the 2023 Annual General Meeting of Shareholders (the Proxy Statement) of Ambrx Biopharma Inc., an exempted company incorporated in the Cayman Islands (the Company), to be held on June 7, 2023 (the Annual
General Meeting), was filed with the Securities and Exchange Commission (SEC) on April 28, 2023. Since then, there have been developments regarding our Board of Directors of the Company (Board). We are reaching out
to you to describe these recent events and to supplement portions of the Proxy Statement, as set forth in this Supplement to the Proxy Statement, which should be read in conjunction with the Proxy Statement.
Recent Developments
Effective as of
May 18, 2023, Dr. Katrin Rupalla resigned as a member of our Board, Chairperson of our Board, and a member of our Compensation Committee and Nominating and Corporate Governance Committee. Dr. Rupallas decision to resign was not
the result of any disagreement with the Company, the Board, management, or any matter relating to the Companys operations, policies or practices; she has resigned to pursue another professional opportunity, which precluded her ability to serve
on any boards of directors.
Following Dr. Rupallas resignation, the Board, with the recommendation of the Nominating and
Corporate Governance Committee, appointed Mr. Stephen Glover as a member of the Board and Chairperson of the Board, to become effective on May 18, 2023. The Board affirmatively determined that Mr. Glover will serve as a Class II
director and meets the requirements for independence under the Nasdaq listing standards and the SEC rules and regulations. There are no family relationships between Mr. Glover and any of our other directors or executive officers. As of the date
of this Supplement, Mr. Glover does not own any ordinary shares of the Company.
Mr. Glover, age 63, has over 32 years of
biopharmaceutical and life sciences experience. Currently he is the Co-Founder, Chairman, Chief Executive Officer, and President of ZyVersa Therapeutics, which he took public in December 2022. He has been at ZyVersa since 2014. ZyVersa is a clinical
stage biopharmaceutical Company advancing a dynamic pipeline of drug candidates with multiple programs built around two proprietary technologies Cholesterol Efflux Mediator VAR 200 in
development to ameliorate renal lipid accumulation that damages the kidneys filtration system in patients with glomerular kidney diseases, and Inflammasome ASC Inhibitor IC 100, targeting damaging inflammation associated with numerous CNS and
other inflammatory diseases. Mr. Glover is Chairman of the Board of Directors of PDS Biotechnology and a Board member of the Coulter Foundation at the University of Miami U Innovation Center and Asclepius Lifesciences. Previously, Mr. Glover was
Co-Founder and Chief Business Officer of Coherus BioSciences, a commercial biologics platform Company focused on delivering biosimilar therapeutics and novel immuno-oncology products which went public in 2014. Prior to Coherus, he was President of
Insmed Therapeutic Proteins and Executive Vice President and Chief Business Officer of Insmed Incorporated, where he was responsible for the creation of its biosimilar business unit and sale of that business to Merck. He led the strategic review
process that resulted in the merger of Insmed and Transave. Before joining Insmed, Mr. Glover held senior-level positions in sales, marketing and operations at Andrx Corporation, Roche Laboratories, Amgen and IMS Health. Our Board and Nominating and
Corporate Governance Committee believe that Mr. Glovers extensive experience in executive roles and public company board positions in the pharmaceutical and biotech industries qualifies him to serve on our Board.