Astellas and Ambrx sign $300 million ADC oncology deal

TOKYO and SAN DIEGO—Astellas Pharma Inc. has entered into acollaboration with Ambrx Inc. for the discovery anddevelopment of novel antibody-drug conjugates (ADCs) against anundisclosed number of targets in oncology.

For this,

Ambrx will receive an upfront payment of $15million from Astellas and as much as $285 million in potential near- andlong-term research, development, regulatory and sales-based milestones

Some of thesemilestones, as well as royalties on any net sales, of course, would be contingent oneventual successful commercialization of products developed as a result of thispartnership, the parties note. For its part, Astellas will receive worldwide rights to develop andcommercialize ADCs for oncology.

Additional terms of the collaboration have not been disclosed.

"Agensys Inc., an affiliate of Astellaswhich specializes in therapeutic antibody research and development in cancer,has significant experience with ADCs as oncology therapeutics and is looking tofurther expand its capabilities in this area. Ambrx offers a novel approach toallow creation of site-specific and highly stable conjugations that have thepotential to further optimize drug delivery to tumor cells," said Dr. DavidStover, an Astellas senior vice president and Agensys site head.

ADCs allow for the targeted delivery of drugs tothe target tissue, the two companies notes, and Ambrx creates optimized ADCs using its site-specificconjugation technology along with proprietary linkers and payloads. In thepreclinical setting, Ambrx ADCs reportedly have demonstrated high potency and a widertherapeutic index than ADCs created using conventional non-specificconjugation.

"We recognize Astellas as a leader in the development of innovativetherapeutics for oncology and are proud to initiate this collaboration," said Lawson Macartney, CEO ofAmbrx. "We lookforward to developing these therapeutics while also advancing our broadpipeline of partnered and wholly owned therapeutic candidates with best-in-classconjugation."

Noting that Astellas currently has in its pipeline AGS-16M8F/AGS-16C3F for renal cancer, ASG-5MEfor prostate cancer and pancreatic cancer and ASG-22ME for solidtumors—all in Phase I—Zacks Investment Research wrote in an investor's note, "We are positive on this collaboration, which should help expand Astellas' capability in the development of ADCs for oncology."

Ambrx

is a clinical-stage biopharmaceuticalcompany using an expanded genetic code to create best-in-class biotherapeutics,including ADCs and proteins with improved pharmacologicproperties. The company is developing ARX201, a long-acting growth hormone thathas successfully completed Phase IIb clinical trials. Ambrx has collaborationsto discover and develop products incorporating Ambrx technology withBristol-Myers Squibb, Eli Lilly and Company and several undisclosed companies.

Astellas employs approximately 17,000 people worldwide, and it has stated a commitment to becoming a global category leader in oncology, as well as urology, immunology, infectious diseases, neuroscience and kidney diseases.