Astellas, Ambrx seal $300M cancer ADC deal

Astellas Pharma has wagered on antibody drug conjugate tech from the San Diego biotech startup Ambrx, paying $15 million upfront and committing up to $285 million more in their collaboration focused in oncology. And it's more proof that major pharma outfits are keen on the advantages of pairing targeted antibodies with potent drug payloads to treat cancer.

Pharma researchers have flocked to biotech outfits with ADC tech such as Ambrx, Mersana Therapeutics and ImmunoGen ($IMGN) in recent years, with the FDA approvals of such drugs as Kadcyla from Roche's ($RHHBY) Genentech and ImmunoGen as well as Adcetris from Seattle Genetics ($SGEN). Both those approvals followed impressive results in the clinic for Kadcyla in HER2 breast cancer and Adcetris in lymphoma.

Each of the antibody drug conjugate players sells the advantages of their technologies. Ambrx comes to the field with preclinical data on ADCs with its site-specific conjugation tech, which the company claims can offer a wider therapeutic index and potency. Last year the company's pitch won over researchers at Merck ($MRK), which agreed to collaborate with Ambrx on chronic diseases beyond oncology with nearly identical financial numbers ($15 million upfront and $288 million in milestones) as the deal with Astellas.

"We recognize Astellas as a leader in the development of innovative therapeutics for oncology and are proud to initiate this collaboration," Lawson Macartney, who took the helm as CEO of Ambrx just months ago, said in a statement. "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."

In the latest collaboration, Ambrx is working the investigators at Agensys, Astellas' antibody research shop. Agensys, which Astellas acquired back in 2007, has some experience with ADCs against cancer and wants to expand its work in the area through the deal with Ambrx, site head David Stover said. Astellas and Ambrx did not disclose which oncology targets they plan to pursue under the pact.

Ambrx, a 2005 Fierce 15 company, has been successful in finding pharma partners in the past based on its antibody work, which stems from the research of chemist Peter Schultz at Scripps. Along with the recent additions of Merck and Astellas, Ambrx has nailed down partnerships with Eli Lilly ($LLY) and Bristol-Myers Squibb ($BMY).

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