Ribox Therapeutics received FDA IND clearance for RXIM-002, an in vivo CAR-T therapy built around circular RNA and delivered via targeted lipid nanoparticles. The company plans to initiate a Phase I study in autoimmune cytopenias, including relapsed or refractory immune thrombocytopenia. Ribox’s approach targets immune cell activity using circRNA, a format designed to drive CAR-T components inside the body rather than manufacturing cells ex vivo. The IND clearance positions the program to begin clinical evaluation of safety, tolerability, and preliminary activity in the autoimmune setting. This is a key step for the emerging category of in vivo CAR-T platforms, where delivery, control, and off-target considerations are central to translational risk management.