TOKYO and SAN DIEGO, April 4, 2013 – Astellas Pharma Inc. (Tokyo: 4503, “Astellas”) today entered into a collaboration with Ambrx Inc. (“Ambrx”) for the discovery and development of novel antibody drug conjugates (“ADCs”).

ADCs allow for the targeted delivery of drugs to the target tissue. Ambrx creates optimized ADCs using its site-specific conjugation technology along with proprietary linkers and payloads. In the preclinical setting, Ambrx ADCs have demonstrated high potency and a wider therapeutic index than ADCs created using conventional non-specific conjugation.

Ambrx will receive an upfront payment of $15 million from Astellas, as well as up to $285 million in potential near and long-term research, development, regulatory and sales-based milestones for an undisclosed number of targets for ADCs in oncology. A portion of these milestones, as well as royalties on any net sales, will be contingent on eventual successful commercialization of products developed as a result of this partnership. Astellas will receive worldwide rights to develop and commercialize ADCs for oncology. Additional terms of the collaboration are not disclosed at this time.

“Agensys, Inc., an affiliate of Astellas which specializes in therapeutic antibody research and development in cancer, has significant experience with ADCs as oncology therapeutics and is looking to further expand its capabilities in this area.  Ambrx offers a novel approach to allow creation of site-specific and highly stable conjugations that have the potential to further optimize drug delivery to tumor cells.” said David Stover, Ph.D., Senior Vice President and Agensys Site Head. 

Added Lawson Macartney, chief executive officer of Ambrx, "We recognize Astellas as a leader in the development of innovative therapeutics for oncology and are proud to initiate this collaboration. We look forward to developing these therapeutics while also advancing our broad pipeline of partnered and wholly owned therapeutic candidates with best-in-class conjugation.”

Contact the Media Relations team
Communications & Investor Relations
Main phone line for Media: +81-3244-3201 
Business hours (JST)
From Monday to Thursday: 8:45 am to 5:45 pm, Friday: 8:45 am to 4:00 pm
(closed on Saturdays, Sundays, national holidays and company holidays)