What Korro Bio does

Korro Bio is a clinical-stage biopharmaceutical company developing RNA editing-based genetic medicines for rare and highly prevalent diseases. Founded in 2018–2019 and headquartered in Cambridge, Massachusetts, the company became publicly traded on Nasdaq (ticker: KRRO) in November 2023 through a reverse merger with Frequency Therapeutics, supported by a concurrent $117 million private placement. The company employs between 101 and 250 people post the November 2025 restructuring, with a market capitalization in the $110–157 million range as of early 2026.

The company's core technology is the OPERA (Oligonucleotide Promoted Editing of RNA) platform, a proprietary approach that co-opts endogenous ADAR enzymes to introduce precise, single-base edits to native mRNA transcripts, producing therapeutic proteins with enhanced functionality. OPERA combines ADAR biology expertise, machine learning–driven oligonucleotide design, custom linker chemistry, and clinically validated tissue-specific delivery modalities including GalNAc conjugates for liver targeting and lipid nanoparticles. First-generation designs under the CHORD (Customized High-fidelity Oligonucleotides for RNA Deamination) trademark offer high specificity and low off-target risk. The pipeline comprises KRRO-121, a GalNAc-conjugated oligonucleotide designed to generate a stabilized de novo glutamine synthetase for hyperammonemia in urea cycle disorders and hepatic encephalopathy; KRRO-111, nominated in May 2026 as a next-generation GalNAc-conjugated candidate for alpha-1 antitrypsin deficiency with >90% SERPINA1 editing in preclinical studies; an AMPKβ1 longevity/metabolic program; and a TARDBP-targeting program for ALS.

Korro Bio is pre-commercial and does not currently generate product revenue; reported Q4 2025 revenue of $1.29 million reflects collaboration activity rather than product sales, and FY2025 net loss was $117.3 million. Revenue will ultimately depend on successful clinical development, regulatory approvals (regulatory filings for KRRO-121 targeted for H2 2026), and commercialization of RNA editing therapies through specialty pharmacy distribution channels serving rare disease populations. The company held $85.2 million in cash at year-end 2025 and raised an additional $85 million via an oversubscribed PIPE financing led by Venrock Healthcare Capital Partners in March 2026, extending cash runway into the second half of 2028.

Name

Korro Bio

Legal name

Korro Bio, Inc.

Website

https://korrobio.com

Company type

Public

Founded year

2019

Operating status

Operating

Headcount range

51–100 employees

Short description

Korro Bio is a clinical-stage biopharmaceutical company developing RNA editing-based genetic medicines using its proprietary OPERA platform, targeting rare and prevalent diseases including urea cycle disorders, hepatic encephalopathy, alpha-1 antitrypsin deficiency, and ALS.

Ownership category

akta.pro rank

Product category

RNA Editing Therapeutics

NAICS

Biological Product (except Diagnostic) Manufacturing (325414), Pharmaceutical and Medicine Manufacturing (3254), Research and Development in Biotechnology (except Nanobiotechnology) (541714)

SIC

Biological Products, (No Disgnostic Substances) (2836)

akta.pro primary industry

RNA Therapeutics Platforms & Design (sequence design, target ID/validation, AI/bioinformatics) (HLAAADAG)

akta.pro secondary industries

RNA Therapeutics Clinical Development (trial design, endpoints, patient stratification) (HLAAADAH), Therapeutic Enzymes & Enzyme Replacement Therapies (ERT) (HLAAAAAK)

Keywords

• RNA editing therapeutics
• Oligonucleotide-based medicines
• Genetic medicine platform
• Liver-targeted therapies
• Rare disease treatments

Headquarters

HQ city

Cambridge

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Operations, Marketing or Sales

Revenue model

1. Product Revenue (Future): As a clinical-stage biopharmaceutical company, Korro Bio does not currently generate product revenue. The company is developing RNA editing-based genetic medicines with lead candidates KRRO-121 for hyperammonemia and KRRO-111 for AATD. Revenue will depend on successful clinical development, regulatory approvals, and commercialization of these therapeutic candidates.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels6 records

Core offering

Korro Bio is a clinical-stage biopharmaceutical company developing a new class of RNA editing-based genetic medicines through its proprietary OPERA (Oligonucleotide Promoted Editing of RNA) platform. The platform leverages endogenous ADAR enzymes to make precise, tissue-directed single-base edits to native mRNA, generating therapeutic proteins with enhanced functionality. Lead clinical-stage candidates include KRRO-121 for hyperammonemia (urea cycle disorders and hepatic encephalopathy) and KRRO-111 for alpha-1 antitrypsin deficiency (AATD), with additional programs targeting AMPKβ1 for liver health and TARDBP for ALS.

Product overview

Korro Bio is a biopharmaceutical company developing a new class of genetic medicines based on its proprietary OPERA (Oligonucleotide Promoted Editing of RNA) platform. The company's pipeline includes multiple programs: KRRO-121 (a GalNAc-conjugated RNA editing oligonucleotide for hyperammonemia in urea cycle disorders and hepatic encephalopathy), KRRO-111 (a next-generation GalNAc-conjugated candidate for Alpha-1 Antitrypsin Deficiency), an AMPKγ1/longevity program for liver health, and a TARDBP program for ALS. The platform technology leverages CHORD (Customized High-fidelity Oligonucleotides for RNA Deamination) designs combined with validated delivery modalities including GalNAc and LNPs.

Differentiator

Problem solved

Functional benefit

Brands

• OPERA®: Oligonucleotide Promoted Editing of RNA platform technology for developing RNA editing genetic medicines
• CHORD™

Products and services

• KRRO-121 KRRO-121 is a GalNAc-conjugated RNA editing oligonucleotide designed to generate a stabilized, de novo variant of glutamine synthetase (GS) protein for treating hyperammonemia in patients with urea cycle disorders (UCDs) and hepatic encephalopathy (HE). The synthetic rescue approach augments ammonia clearance, addressing the underlying metabolic defect in hyperammonemia-driven diseases.
• KRRO-111 KRRO-111 is a GalNAc-conjugated RNA editing oligonucleotide designed to address the underlying genetic cause of Alpha-1 Antitrypsin Deficiency (AATD) by editing the SERPINA1 transcript to restore production of normal AAT protein, clearing protein aggregates from liver cells and preserving lung function.
• AMPKβ1/Longevity Program A GalNAc-conjugated program targeting AMPKβ1 pathway activation in the liver for restoring metabolic status and improving liver function, designed to avoid activating AMPK in other parts of the body.
• TARDBP Program for ALS A proprietary oligonucleotide program targeting the mRNA for TAR DNA binding protein 43 (TDP-43), which is associated with the development of amyotrophic lateral sclerosis (ALS), aiming to disrupt TDP-43 protein aggregation.

Quantifiable outcome

• >90% SERPINA1 transcript editing with KRRO-111 in preclinical studies
• +5 more outcomes

Segments4 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature6 records

Partnerships

One partnership is on record.

• Novo NordiskcoreStrategic or Co-development Partner · 12 November 2025Research and license agreement for RNA editing technology. Korro Bio announced pausing the collaboration for one year in November 2025 following the failure of KRRO-110 in the Phase I/IIa REWRITE trial. The pause was part of strategic restructuring to reallocate resources and extend cash runway.

Scale indicators13 records

Recent moves6 records

Expansion highlights6 records

Direct peers

• Wave Life Sciences: Wave Life Sciences is the most direct peer, developing ADAR-mediated RNA editing oligonucleotides (PRISM platform, WVE-006 for AATD). Both companies compete on the same ADAR editing modality for overlapping liver-targeted indications including AATD.
• ProQR Therapeutics: ProQR Therapeutics develops Axiomer RNA editing oligonucleotides leveraging ADAR biology for rare genetic diseases, with overlap in liver-targeted and CNS indications. Closely comparable platform technology and target disease areas.

Broad incumbents

• Alnylam Pharmaceuticals: Alnylam is the established leader in GalNAc-conjugated nucleic acid therapeutics, with Korro's board director Rachel Meyers previously serving as SVP of Research. Comparable GalNAc liver delivery technology and oligonucleotide chemistry infrastructure.
• Arrowhead Pharmaceuticals: Arrowhead develops GalNAc-conjugated RNAi triggers targeting liver indications including AATD and other rare diseases. Closely comparable delivery modality and liver-targeted rare disease strategy.
• Ionis Pharmaceuticals: Ionis is the leading antisense oligonucleotide company with established liver-targeted and CNS programs for rare diseases. Comparable oligonucleotide chemistry capabilities and regulatory pathway experience.
• Beam Therapeutics: Beam develops base editing and other precision genetic medicines, including liver-targeted programs for AATD and other rare diseases. Comparable approach to single-base corrections for genetic diseases.

Emerging players

• Intellia Therapeutics: Intellia is a co-founder-affiliated gene editing company (Nessan Bermingham, Jean-Francois Formela) developing in vivo CRISPR/Cas9 therapies including liver-targeted programs. Adjacent genetic medicine approach for similar indications.
• Verve Therapeutics: Verve develops in vivo base editing therapies for cardiovascular and liver diseases using GalNAc delivery. Comparable liver-targeted in vivo genetic medicine approach using validated delivery technology.
• Airna Bio: Airna is an RNA editing biotech developing ADAR-based oligonucleotide therapeutics for rare diseases. Directly comparable RNA editing modality and indication focus.
• Ascidian Therapeutics: Ascidian develops RNA editing therapies for neurological and other rare diseases using a distinct RNA exon editing approach. Comparable focus on RNA-level genetic correction for severe genetic diseases.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks7 records

Key highlights7 records

Customer concentration

• Xx.com/KorroBio
• LinkedInlinkedin.com/company/korro-bio

Revenue estimate

Valuation estimate

Number of profiles

Profiles12 records

Funding overview

Funding rounds5 records

Investors27 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A1 record

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Korro Bio