Kyowa Kirin Co. Ltd. has partnered with Amgen Inc. to jointly develop and commercialize KHK-4083, Kyowa Kirin’s phase III-ready anti-OX40 fully human monoclonal antibody for the potential treatment of atopic dermatitis. Kyowa Kirin will receive a $400 million up front, while milestone payments could add an additional $850 million. Significant royalty payments on future global sales could sweeten the blockbuster deal.