Korro Bio’s shares plunged about 81% after Phase I/IIa REWRITE data for KRRO‑110 failed to reach projected alpha‑1 antitrypsin (AAT) thresholds. The company reported insufficient functional M‑AAT production and has launched a strategic restructuring that will cut roughly 34% of its workforce to extend cash into H2 2027. Management cited transitioning R&D to a GalNAc‑conjugated construct for clinical entry in 2027 and noted one‑time restructuring charges. Analysts flagged the shortfall versus competitors’ AAT restoration metrics and will monitor Korro’s next‑generation construct and any follow‑on clinical data.