Korro Bio (KRRO) investor relations material

Strategic vision and future plans

• KRRO-121 is positioned as a first-in-class, liver-targeted RNA editing therapy for ammonia control in urea cycle disorders (UCD) and hepatic encephalopathy (HE), aiming to address significant unmet needs in both rare and common hyperammonemia conditions.

• The company plans to submit a regulatory application for KRRO-121 in the second half of 2026, with the goal of demonstrating robust ammonia-lowering effects and improved patient outcomes in clinical trials.

• KRRO-121, a GalNAc-conjugated ASO, leverages the OPERA platform to transiently stabilize glutamine synthetase (GS) in the liver, offering a differentiated approach compared to current DNA editing or oral therapies.

• The platform's transient, non-permanent editing is designed to enhance safety and flexibility, with potential expansion to additional disease targets beyond UCD and HE.

• Vision to become a leader in modulating disease biology through innovative RNA editing approaches.

Financial guidance and market opportunity

• UCD represents approximately 9,000 addressable patients in the US and Europe, with a $1.5 billion market opportunity; HE represents over 200,000 addressable patients and a $2 billion market opportunity.

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

• Strong pharmacoeconomic case for treatments that reduce hospitalizations and healthcare burden in HE.

• Current standard of care for UCD and HE is inadequate, requiring frequent dosing and strict dietary management, leading to poor compliance and high rates of hospitalization.

• The company expects that the introduction of effective therapies like KRRO-121 could increase diagnosis rates for UCD as awareness and treatment options improve.

Scientific and clinical development updates

• Preclinical data show that KRRO-121 stabilizes GS in the liver, resulting in robust ammonia clearance across multiple UCD genotypes and in humanized mouse models.

• Only 20%-25% RNA editing is required to achieve therapeutic benefit, with editing efficiencies up to 40% observed in preclinical studies.

• Preclinical safety studies in non-human primates showed no adverse findings, with >90% liver delivery and no impact on key safety markers.

• Mechanism validated by human genetic evidence and animal models, supporting a pan-UCD approach and potential for chronic maintenance therapy.

• Initial clinical studies will focus on demonstrating ammonia reduction as a primary endpoint, with further studies to assess dosing, safety, and hard outcomes such as crisis reduction and hospitalization rates.