Regeneron and Telix announced a major expansion into radiopharmaceuticals through a co-development and co-commercialization collaboration worth up to $2.1 billion. The partnership pairs Regeneron’s VelocImmune-derived antibody discovery platform with Telix’s radiopharmaceutical development, manufacturing, and global supply-chain capabilities. The companies outlined a 50/50 cost and profit-sharing structure for four initial solid-tumor programs, with options to add four more. Telix is set to receive a $40 million upfront payment for the first programs, and the deal includes potential milestones and royalties tied to program success. Regeneron retains expansion rights, while Telix can also choose whether to co-fund commercialization. Regeneron’s entry reflects continued investor and industry attention on theranostics, where paired diagnostics can guide patient selection and track response—an approach aimed at tightening the therapeutic funnel in oncology.