Korro Bio announced disappointing early clinical performance of its RNA‑editing candidate for alpha‑1 antitrypsin deficiency and cut roughly one‑third of its workforce while pivoting delivery strategy toward GalNAc approaches. The company said the single‑administration program produced functional protein but fell short of projected levels, prompting a strategic reset. Management halted further development of the original formulation, shifted to nominate KRRO‑121 for hyperammonemia, and reprioritized pipeline assets to extend cash runway into mid‑2027. The market reaction was severe, with shares plunging and investor scrutiny on translational robustness of RNA‑editing platforms. The episode illustrates the execution risks in nascent genetic medicine modalities and underscores the importance of delivery chemistry and dose optimization to achieve therapeutic thresholds in vivo.