Company Overview of Ambrx, Inc.

Ambrx and Zhejiang Medicine Co. Ltd. announced that they have formed a collaboration to develop and commercialize ARX788, Ambrx's most advanced internally developed site-specific antibody drug conjugate (ADC) targeting Her2-positive breast cancer. Under the agreement, Ambrx and ZMC will continue the development of ARX788, with ZMC bearing the ongoing development cost. ZMC will receive commercial rights in China while Ambrx retains commercial rights outside of China and receives royalties on sales of the product in China. ZMC will manufacture the product to world-class standards for clinical and commercial supplies on a global basis. WuXi PharmaTech will provide integrated services for ARX788, including the development and manufacturing of the toxin, antibody and ADC, pre-clinical development and clinical trials.

Ambrx entered into a collaboration agreement with Bristol-Myers Squibb for the discovery and development of novel antibody drug conjugates using Ambrx's protein medicinal chemistry technology. Under terms of the agreement, Ambrx will receive an upfront payment of $15 million, funding for discovery and research activities, and potential development, regulatory and sales based milestone payments of up to $97 million per product resulting from the collaboration. Bristol-Myers Squibb will receive worldwide rights to develop and commercialize products resulting from the collaboration, and Ambrx is eligible to receive royalties on net sales.

Astellas Pharma Inc. entered into a collaboration with Ambrx Inc. for the discovery and development of novel antibody drug conjugates. 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.