Little more than half-a-year after closing its $78 million series A financing, Artiva Biotherapeutics Inc. has inked a new global licensing deal with Merck & Co. Inc. to develop up to three natural killer (NK) cell therapies engineered with chimeric antigen receptors (CAR) against tumor-associated antigens of its choosing. Merck will pay Artiva $30 million up front for two initial programs, plus $15 million more should it opt into the third. Each program carries $612 million in potential development and commercial milestone payments. With unfettered success, total deal value could hit $1.88 billion, plus royalties.