Korro Bio’s shares plunged 81% after Phase I/IIa REWRITE data for KRRO‑110 fell short of projections in alpha‑1 antitrypsin deficiency (AATD). The company disclosed protein increases below the protective threshold and announced a 34% workforce reduction to extend runway, plus a pivot to a GalNAc‑conjugated construct with a 2027 clinic entry planned. The CMO resigned and will advise temporarily. Investors and analysts compared Korro’s protein increases unfavorably with rivals Wave and Beam, prompting an urgent restructuring and R&D re‑focus. The move underscores investor intolerance for underperforming early‑stage modalities and the cost of translational gaps between preclinical projections and human outcomes.