Korro Receives European Medicines Agency Orphan Drug Designation for KRRO-110

Core Viewpoint - Korro Bio, Inc. has received orphan drug designation from the European Medicines Agency (EMA) for its investigational medicine KRRO-110, aimed at treating Alpha-1 Antitrypsin Deficiency (AATD), marking a significant milestone for the company and highlighting the urgent need for innovative therapies in this area [1][2]. Company Overview - Korro Bio is a clinical-stage biopharmaceutical company focused on developing genetic medicines through RNA editing for both rare and prevalent diseases [6]. - The company utilizes its proprietary RNA editing platform, Oligonucleotide Promoted Editing of RNA (OPERA), to create differentiated programs that allow for precise and transient single base edits [6]. Product Development - KRRO-110 is currently undergoing evaluation in the Phase 1/2a REWRITE clinical study, with an interim readout expected in the second half of 2025 [2][4]. - The REWRITE study will assess the safety and tolerability of KRRO-110 in up to 64 participants, including healthy adults and AATD patients [4]. Orphan Drug Designation - The EMA grants orphan drug designation to medicines for life-threatening or chronically debilitating diseases affecting fewer than 5 in 10,000 people in the EU, providing various development incentives such as protocol assistance and market exclusivity upon approval [3]. - KRRO-110 also received orphan drug designation from the U.S. FDA in March 2025, further supporting its development [2]. Disease Background - AATD is a genetic disorder caused by a mutation in the SERPINA1 gene, leading to pulmonary emphysema and hepatic cirrhosis among affected adults [5]. - KRRO-110 aims to repair the SERPINA1 RNA to restore normal AAT protein secretion, potentially improving liver function and preserving lung function [5].