Sanofi entered a partnership with ScionxBio to screen Sanofi’s mRNA candidates using ScionxBio’s platform designed to produce long-acting RNA formulations. The deal marks ScionxBio’s first partnership since it separated from Eleven Therapeutics, highlighting Sanofi’s continued push for duration-focused RNA drug development. For the field, long-acting approaches address a core limitation for RNA therapeutics: achieving durable exposure without repeated dosing. The screening agreement indicates ScionxBio’s role upstream, potentially accelerating which candidates proceed based on pharmacology-relevant formulation performance. Key follow-on milestones will include selection criteria outcomes and whether the partnership produces lead programs with clear differentiation versus existing delivery approaches.