Korro Bio (KRRO) investor relations material

Future plans and development timeline

• KRRO-121, a first-in-class RNA editing therapy, targets ammonia control in urea cycle disorders (UCD) and hepatic encephalopathy (HE), with regulatory filing for first human trials expected in the second half of 2026.

• The therapy leverages liver-specific stabilization of glutamine synthetase (GS) to enhance ammonia clearance, aiming for infrequent subcutaneous dosing and potential diet liberalization.

• Preclinical data show robust efficacy across multiple UCD and HE genotypes and in humanized mouse models, supporting a pan-UCD approach.

• The OPERA platform enables transient, high-precision RNA editing without permanent DNA changes, opening broader applications beyond rare diseases.

• Next steps include regulatory alignment and initiation of clinical studies to demonstrate ammonia-lowering effects in targeted patient populations.

Financial guidance and market opportunity

• UCD and HE represent significant unmet needs, with a combined addressable market of over $3.5 billion and more than 230,000 patients in the US and Europe.

• KRRO-121 is positioned to offer a differentiated, convenient therapy with potential to reduce hospitalizations and improve quality of life, especially compared to current therapies requiring multiple daily doses.

• The product profile supports strong patient engagement and recruitment, with anticipated pharmacoeconomic benefits due to reduced healthcare utilization.

• Expansion opportunities include prevention of initial HE events and broader application in ammonia-driven diseases.

• Additional market expansion possible in EU and UK, with 5,100 UCD and 150,000 HE patients.

Scientific and clinical developments

• KRRO-121’s mechanism is validated by human genetic evidence and preclinical studies, showing that stabilizing GS in the liver can significantly lower ammonia without affecting the brain.

• Safety data from non-human primates indicate liver-restricted delivery, no CNS exposure, and a clean toxicology profile at doses above the anticipated therapeutic range.

• The platform’s ability to achieve therapeutic benefit with only 20%-25% RNA editing efficiency reduces the need for maximal editing, minimizing risk.

• Clinical endpoints will focus on ammonia reduction, with crisis rates and diet liberalization as potential secondary outcomes; regulatory precedent suggests approval may hinge on favorable ammonia control.

• The company anticipates providing further clinical and regulatory updates later in the year as development progresses.