A pharmacovigilance analysis of nearly five million adverse-event reports found that liver injury after CAR T-cell therapy is predominantly early and linked to cytokine release syndrome, while also detecting a persistent CRS-independent signal in idecabtagene vicleucel. The findings argue for monitoring approaches that account for both CRS timing and agent-specific risks, rather than assuming all hepatotoxicity is purely cytokine-mediated. For CAR T developers and transplant centers, the study supports refining risk mitigation protocols and prospective evaluation plans for the persistent signal region.