A case report in Respirology Case Reports described an initial 1-milligram dose of tarlatamab followed by fatal tumor lysis syndrome in a woman with relapsed small-cell lung cancer. The complication emerged six days after the starter dose, despite initial low-dose exposure and patient monitoring. The report adds to the safety conversation around step-up dosing strategies for T-cell redirection therapies, emphasizing that even early dosing can carry severe metabolic risk and requires careful risk mitigation protocols.