Ambrx and Zhejiang Medicine Co. Ltd. Form Collaboration to Develop and Commercialize Ambrx’s Antibody Drug Conjugate for Breast Cancer

Published: June 16, 2013

By WuXi PharmaTech (Cayman) Inc.

SAN DIEGO AND SHANGHAI, JUNE 16, 2013 — /PRNewswire/ — Ambrx and Zhejiang Medicine Co. Ltd. (ZMC) today 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.

“We are excited to initiate this unique collaboration with ZMC and WuXi, which allows us to team up with China’s leading pharmaceutical and CRO companies to efficiently develop ARX788, our most advanced ADC therapeutic candidate for both breast cancer and gastric cancer indications,” said Lawson Macartney, Ph.D., Chief Executive Officer of Ambrx. “This collaboration allows Ambrx to further extend our pipeline of ADCs and gain access to the China market through our partnership with ZMC. Our experience with site-specific ADC technology has shown that we have the potential to create best-in-class therapeutic candidates, and we look forward to advancing ARX788 into the clinic to understand its full potential.”

Chunbo Li, Chairman of Zhejiang Medicine, commented, “We are honored to partner with Ambrx, a leading biotech company, in ADC drugs. We will work with WuXi PharmaTech to accelerate the development and commercialization of ARX788 in China to bring benefits to Her2-positive cancer patients. The partnership will help ZMC undertake pioneering work in the development of monoclonal antibodies and ADCs. The partnership will also help ZMC establish long-term and mutually beneficial relationships with leading global companies and advance our position in the biopharmaceutical industry.”

“Our collaboration with Ambrx and ZMC on ARX788 is another example of how WuXi’s comprehensive, integrated, open-access R&D services platform enables our partners to develop innovative products efficiently and cost-effectively to benefit the world’s patients,” said Dr. Ge Li, Chairman and CEO of WuXi PharmaTech. “We are very pleased to offer our partners integrated services at global standards ranging from toxins to antibodies, from CMC development to pre-clinical studies, from regulatory strategy to clinical trials.”

About Ambrx

Ambrx Inc. is a clinical stage biopharmaceutical company using an expanded genetic code to create best-in-class biotherapeutics, including ADCs, bispecific antibodies and proteins with improved pharmacologic properties. The company is developing ARX201, a long-acting growth hormone that has successfully completed Phase 2b clinical trials. In addition to its most recent ADC collaborations with Merck, Astellas and Bristol-Myers Squibb, Ambrx has collaborations to discover and develop products incorporating Ambrx technology with Bristol-Myers Squibb, Eli Lilly and several undisclosed companies. Ambrx is advancing a robust portfolio of product candidates that are optimized for efficacy, safety and ease of use in multiple therapeutic areas.

For additional information, visit www.ambrx.com.

About Zhejiang Medicine Co. Ltd.

Zhejiang Medicine Co. Ltd. (ZMC) is a major China-based pharmaceutical company listed on the Shanghai stock exchange. It is a leading global manufacturer of fat-soluble vitamins and bacteria-resistant antibiotics. ZMC’s products are exported to the United States and many EU countries. In 2012, total revenue reached 5.3 billion RMB and total profit reached 855 million RMB. ZMC has strong capabilities in technology innovation and new drug R&D and has received the National High-Tech Enterprise and Model Innovation Enterprise awards in China. ZMC has a national-level R&D center and post-doctorate R&D sponsorship. Three ZMC research projects were awarded second prize in the National Technology Advancement competition and one was awarded second prize in the National Technology Innovation competition. To date, ZMC has 126 issued patents, including 15 global patents, and has four class 1 drugs in clinical trials.

About WuXi PharmaTech

WuXi PharmaTech is a leading pharmaceutical, biotechnology and medical device R&D outsourcing company, with operations in China and the United States. As a research-driven and customer-focused company, WuXi PharmaTech provides pharmaceutical, biotechnology and medical device companies with a broad and integrated portfolio of laboratory and manufacturing services throughout the drug and medical device R&D process. WuXi PharmaTech’s services are designed to help its global partners shorten the cycle and lower the cost of drug and medical device R&D. The operating subsidiaries of WuXi PharmaTech are known as WuXi AppTec.

For more information, please contact:

Ambrx

Ian Stone                                             (619) 308-6541

Zhejiang Medicine Co. Ltd.

ZhuJun Yu or Jing Zhu (Investor Relations) +86-571-87213883 [email protected]

WuXi PharmaTech

Ronald Aldridge (for investors) (201) 585-2048 [email protected]

Aaron Shi (for the media) +86-21-5046-4362 [email protected]

SOURCE WuXi PharmaTech (Cayman) Inc.