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Korro Bio, Inc. (KRRO)

CIK: 0001703647. SIC: 2834 Pharmaceutical Preparations. Latest 10-K as of: 2026-03-12.

SIC breadcrumb: Manufacturing > Chemicals And Allied Products > SIC 2834 Pharmaceutical Preparations

SEC company page: https://www.sec.gov/edgar/browse/?CIK=1703647. Latest filing source: 0001193125-26-104156.

Selected Fundamentals

MetricValueUnitFYFiled
Revenue6,392,000USD20252026-03-12
Net income-117,260,000USD20252026-03-12
Assets113,506,000USD20252026-03-12

Financials

Annual standardized facts from SEC companyfacts as of latest extracted filing date 2026-03-12. Source: https://data.sec.gov/api/xbrl/companyfacts/CIK0001703647.json. Derived margins, ratios, and free cash flow are computed from the extracted annual SEC facts.

Flow metrics use full-year FY periods from 10-K/10-K/A filings; balance-sheet metrics use FY-end instants. Free cash flow = operating cash flow - capital expenditures. Missing metrics are omitted rather than fabricated.

Metric2016201720182019202020212022202320242025
Revenue2,271,0006,392,000
Net income-20,237,000-19,168,000-18,746,000-26,511,000-84,686,000-58,032,000-81,172,000-83,581,000-117,260,000
Operating income-16,306,000-18,944,000-20,675,000-27,550,000-84,031,000-58,998,000-84,534,000-91,910,000-121,855,000
Diluted EPS-227.42-53.08-9.37-12.48
Operating cash flow-14,614,000-17,024,00034,216,000-45,188,000-76,059,000-53,645,000-67,283,000-60,074,000-78,561,000
Capital expenditures1,863,000436,0001,064,0006,671,0002,914,0005,136,0007,836,00017,902,000518,000
Assets44,548,000223,218,000264,722,000185,358,00073,742,000221,663,000226,240,000113,506,000
Liabilities4,122,00055,860,00072,231,00054,534,0008,910,00051,752,00065,825,00062,067,000
Stockholders' equity-9,663,000-29,642,000-48,282,000167,358,000192,491,000-42,208,000-99,031,000169,911,000160,415,00051,439,000
Cash and cash equivalents42,189,000200,158,000220,341,00079,635,00036,333,000166,150,00055,643,00021,824,000
Free cash flow-16,477,000-17,460,00033,152,000-51,859,000-78,973,000-58,781,000-75,119,000-77,976,000-79,079,000

Ratios

ROE and ROA use period-end equity/assets. Liabilities / equity uses total liabilities divided by stockholders' equity. Current ratio uses current assets divided by current liabilities when both are reported.

Metric2016201720182019202020212022202320242025
Return on equity-11.20%-13.77%-47.77%-52.10%-227.96%
Return on assets-43.03%-8.40%-10.01%-45.69%-78.70%-36.62%-36.94%-103.31%
Liabilities / equity0.330.380.300.411.21
Current ratio11.384.198.4511.796.568.878.796.90

Financial Charts

Quarterly

Quarterly standardized facts from SEC companyfacts as of latest extracted filing date 2026-05-07. Source: https://data.sec.gov/api/xbrl/companyfacts/CIK0001703647.json.

Flow metrics use discrete quarter-length periods from 10-Q/10-Q/A filings. Q4 revenue and net income are derived only when annual FY and nine-month YTD facts exist for the same fiscal year; derived Q4 values are labeled. EPS Q4 is not derived.

QuarterEnd DateRevenueNet IncomeDiluted EPSMethod
2023-Q22023-06-30-10,796,000reported discrete quarter
2023-Q32023-09-30-11,614,000-0.31reported discrete quarter
2023-Q42023-12-31-39,219,000derived Q4 = FY annual - nine-month YTD
2024-Q12024-03-31-19,557,000-2.44reported discrete quarter
2024-Q22024-03-31-19,557,000reported discrete quarter
2024-Q22024-06-30-2.43reported discrete quarter
2024-Q32024-06-30-21,826,000reported discrete quarter
2024-Q32024-09-30-2.26reported discrete quarter
2024-Q42024-12-31-21,199,000derived Q4 = FY annual - nine-month YTD
2025-Q12025-03-312,550,000-23,387,000-2.49reported discrete quarter
2025-Q22025-03-31-23,387,000reported discrete quarter
2025-Q22025-06-301,460,000-2.74reported discrete quarter
2025-Q32025-06-30-25,770,000reported discrete quarter
2025-Q32025-09-301,090,000-1.92reported discrete quarter
2025-Q42025-12-311,292,000-50,042,000derived Q4 = FY annual - nine-month YTD
2026-Q12026-03-310.00-19,625,000-1.69reported discrete quarter

Quarterly Charts

Macro Cross-References

Latest quarter (10-Q)

Latest 10-Q source: 0001193125-26-210303.

Extracted structurally from real Item 2 body heading to real Item 3/4 boundary. Confidence: high. Filing date: 2026-05-07. Report date: 2026-03-31.

Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

You should read the following discussion and analysis of our financial condition and results of operations together with our unaudited condensed consolidated financial statements and related notes included elsewhere in this Quarterly Report and the audited consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2025, or the 2025 10-K. Some of the information contained in this discussion and analysis, including information with respect to our plans and strategy for our business and related financing, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth under the heading “Risk Factors” in Part II, Item 1A of this Quarterly Report our actual results could differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis. See also “Cautionary Statement Regarding Forward-Looking Statements.”

Overview

We are a biopharmaceutical company leveraging a novel oligonucleotide promoted editing of RNA, or OPERA, platform to develop a new class of genetic medicines for rare and highly prevalent diseases. OPERA provides precise, tissue-directed delivery of oligonucleotides that modify the targeted native mRNA transcript to repair or form a de-novo protein with enhanced functionality. The platform combines a suite of capabilities consisting of sophisticated knowledge of transcription biology through ADAR proteins (Adenosine Deaminases Acting on RNA), machine learning optimization of oligonucleotides, linker chemistry expertise, along with use of a highly targeted tissue-specific delivery methodology. As such, the OPERA platform has enabled us to generate and advance a portfolio of differentiated programs that are designed to harness the body’s natural RNA editing process, providing precise yet transient single base edits to produce therapeutic proteins with augmented activity versus its endogenous counterpart. By editing RNA instead of DNA, we are expanding the reach of genetic medicines by delivering additional precision and tunability, which has the potential for increased specificity and improved long-term tolerability. Using an oligonucleotide-based approach, we expect to bring our medicines to patients by leveraging our proprietary OPERA platform with precedented delivery modalities, including N-acetylgalactosamine, or GalNAc, conjugated for delivery for subcutaneous administration, manufacturing know-how, and established regulatory pathways of approved oligonucleotide medicines. However, the scientific evidence to support the feasibility of developing our development candidates using our RNA editing technology is both preliminary and limited. Moreover, regulators have not yet established any definitive guidelines related to overall development considerations for RNA editing therapies and limited clinical data has been generated to date.

The versatility of RNA editing combined with our OPERA platform broadens the therapeutic target space significantly. The advent of large-scale genome sequencing has progressively revealed causal genetic variation underlying several human diseases, both rare and highly prevalent. Genetic mutations, including single nucleotide variants, or SNVs, implicated in disease have been found to be diverse in nature and can affect the function of genes and their associated downstream biochemical pathways. Data correlating DNA to RNA to disease phenotype have demonstrated that SNVs lead to a loss-of-function or a gain-of-function of the gene. In addition, the majority of SNVs implicated in complex diseases are due to modulation of gene function. By editing RNA to mimic a SNV, we believe we will be able to address unmet patient need by transiently modifying gene expression and the resultant protein function.

We continue to make meaningful advancements across our programs, including KRRO-121 as a potential first-in-class treatment for hyperammonemia that has the potential to address substantial unmet need in patients with poor ammonia control, including those with urea cycle disorders, or UCD, and hepatic encephalopathy, or HE. KRRO-121 is a GalNAc-conjugated RNA editing oligonucleotide for the potential treatment of hyperammonemia in patients with UCDs of any mutational background as well as patients with HE. Utilizing our proprietary OPERA platform, KRRO-121 is designed to generate a stabilized, de novo glutamine synthetase, or GS, protein, a critical enzyme involved in ammonia clearance. This synthetic rescue approach is designed to augment ammonia clearance in hyperammonemia-driven diseases such as UCDs and HE. Our preclinical data support the potential for KRRO-121 to be a pan-UCD treatment that may control ammonia levels, along with the potential to enable diet liberalization, reduce dependence on nitrogen scavengers, and lower the risk of hyperammonemic crises. KRRO-121 also has the potential to enhance ammonia control in HE patients, which may reduce the risk of recurrent HE episodes. KRRO-121 may offer infrequent subcutaneous dosing, which, if confirmed in clinical studies, could offer significant improvement over current treatments that require multiple daily doses. KRRO-121 has the potential to be a differentiated, first-in-class, disease-modifying therapy for both UCD and HE. We anticipate a regulatory filing to enable commencement of a first-in-human trial in the second half of 2026.

We are also advancing early-stage research and development programs highlighted by a GalNac-conjugated oligonucleotide for AATD. We are on track to announce our AATD development candidate in second quarter of 2026 and plan to nominate a development candidate for a third GalNAc-conjugated program in the second half of 2026.

Since inception, we have focused primarily on organizing and staffing our company, business planning, raising capital, securing related intellectual property, and conducting research and development activities for our potential programs and development candidates. Since inception, we have funded our operations primarily through the private placement of our equity securities. To date, we have raised approximately $501.0 million of aggregate gross proceeds from sales of our equity securities.

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We have incurred significant operating losses since inception. Our net losses were $19.6 million and $23.4 million for the three months ended March 31, 2026 and 2025, respectively. We had an accumulated deficit of $403.5 million as of March 31, 2026. We expect to continue to incur significant and increasing expenses and operating losses and negative operating cash flows for the foreseeable future as we continue our research and development efforts, advance development candidates through clinical development, and seek regulatory approvals for our development candidates. Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending on the timing of our preclinical studies, initiation and conduct of any clinical trials, and our expenditures on other research and development activities, including the expansion of our pipeline.

We do not have any development candidates approved for sale and have not generated any revenue from product sales. We will not generate revenue from product sales unless and until we successfully obtain regulatory approval for our development candidates, if ever, and as appropriate, move pipeline candidates into the clinic and complete clinical development. If we obtain regulatory approval for our development candidates and do not enter into third-party commercialization partnerships, we expect to incur significant expenses related to developing commercialization capabilities to support product sales, marketing, manufacturing and distribution activities. As a result, we will need substantial additional funding to support our continuing operations and pursue our development and growth strategy. Until we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of public or private offerings of securities, debt financings or other sources, such as potential collaboration agreements, strategic alliances and licensing arrangements. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed on acceptable terms, or at all. Our failure to raise capital or enter into such agreements as, and when needed, could have a negative effect on our business, results of operations and financial condition.

Recent Developments

At-the-Market Offering Program

In January 2026, we issued 501,861 shares of common stock under our December 2024 at-the-market sales agreement for gross proceeds of $5.1 million, before deducting offering expenses of approximately $0.1 million.

March 2026 Private Placement

On March 9, 2026, we entered into a subscription agreement with certain new and existing accredited investors to issue and sell in a private placement, or a PIPE, (i) an aggregate of 4,501,928 shares of our common stock at a purchase price of $11.11 per share and (ii) pre-funded warrants to acquire an aggregate 3,148,836 shares of our common stock (at an exercise price of $0.001 per share) at a purchase price of $11.109 per pre-funded warrant. The PIPE, which closed March 10, 2026, resulted in gross cash proceeds of approximately $85.0 million, before deducting placement agent fees and offering expenses of approximately $4.7 million. No pre-funded warrants have been exercised as of March 31, 2026.

Financial Operations Overview

Revenue

We have not generated any revenue from product sales, and do not expect to generate any revenue from the sale of products in the near future. During the three months ended March 31, 2026 and 2025, we recognized $0.0 million and $2.6 million of collaboration revenue, respectively, which is related to our research collaboration and license agreement with Novo Nordisk. In November 2025, we agreed to a 12-month pause on such collaboration with Novo Nordisk, accordingly, we do not expect to recognize any material collaboration revenue under such agreement during the 12-month hold period.

For additional information about our revenue recognition policy and our collaboration and license agreement with Novo Nordisk, which is now paused, see Note 11 in the condensed consolidated financial statements included in this Quarterly Report.

Operating Expenses

Research and Development Expenses

Research and development expenses consist primarily of costs incurred for our research activities, including our discovery of novel genetic medicines and the development of our development candidates, salaries and benefits, and third-party license fees. We expense research and development costs as incurred, which include:

•
employee-related expenses, including salaries, bonuses, benefits, stock-based compensation and other related costs for those employees involved in research and development efforts;

•
expenses incurred under agreements with contract research organizations, or CROs, that conduct our preclinical studies and clinical trials;

18

•
costs of purchasing lab supplies and non-capital equipment used in our preclinical activities and in manufacturing preclinical study materials, as well as supplies and materials used to manufacture clinical trial materials;

•
costs of outside consultants and contractors engaged in research and development activities, including their fees and travel expenses;

•
payments made under third-party licensing agreements; and

•
direct and allocated expenses for facilities.

Costs for certain activities are recognized based on an evaluation of the progress to completion of specific tasks using data such as information provided to us by our vendors an

[Excerpt truncated for page length; source filing is linked above.]

Latest 10-K MD&A

Extracted structurally from real Item 7 body heading to real Item 7A/8 boundary. Confidence: high. Filing date: 2026-03-12. Report date: 2025-12-31.

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

You should read the following discussion and analysis of our financial condition and results of operations together with our audited consolidated financial statements and related notes included elsewhere in this Annual Report on Form 10-K. Some of the information contained in this discussion and analysis, including information with respect to our plans and strategy for our business and related financing, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth under the heading “Risk Factors” in Part I, Item 1A of this Annual Report on Form 10-K our actual results could differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis. See also “Cautionary Statement Regarding Forward-Looking Statements.”

Overview

We are a biopharmaceutical company with a mission to discover, develop and commercialize a new class of genetic medicines based on editing RNA, enabling the treatment of both rare and highly prevalent diseases.

We are generating a portfolio of differentiated programs that are designed to harness the body’s natural RNA editing process to effect a precise yet transient change to a single nucleoside (adenosine to an inosine edit). By editing RNA instead of DNA, we are expanding the reach of genetic medicines by delivering additional precision and tunability, which has the potential for increased specificity and improved long-term tolerability. We use an oligonucleotide-based approach and expect to bring our medicines to patients by leveraging our proprietary platform with precedented delivery modalities, including N-acetylgalactosamine, or GalNAc, -conjugated delivery for subcutaneous administration, manufacturing know-how, and established regulatory pathways of approved oligonucleotide medicines. However, the scientific evidence to support the feasibility of developing our development candidates using our RNA editing technology is both preliminary and limited. Moreover, regulators have not yet established any definitive guidelines related to overall development considerations for RNA editing therapies and limited clinical data has been generated to date.

The versatility of RNA editing combined with our OPERA platform broadens the therapeutic target space significantly. The advent of large-scale genome sequencing has progressively revealed causal genetic variation underlying several human diseases, both rare and highly prevalent. Genetic mutations, including SNVs implicated in disease have been found to be diverse in nature and can affect the function of genes and their associated downstream biochemical pathways. Data correlating DNA to RNA to disease phenotype have demonstrated that SNVs lead to a loss-of-function or a gain-of-function of the gene. In addition, the majority of SNVs implicated in complex diseases are due to modulation of gene function. By editing RNA to mimic a SNV, we believe we will be able to address unmet patient need by transiently modifying gene expression and the resultant protein function.

We continue to make meaningful advancements across our programs, including KRRO-121 as a potential first-in-class treatment for hyperammonemia that has the potential to address substantial unmet need in patients with poor ammonia control, including those with UCD and HE. KRRO-121 is an RNA-editing oligonucleotide conjugated with GalNAc in development for the potential treatment of UCDs of any mutational background in adults and adolescents. Utilizing our proprietary platform, we designed KRRO-121 to edit the GLUL transcript (the gene for the GS protein), to generate a stabilized, de novo variant of GS with enhanced ammonia clearance capacity. This synthetic rescue approach creates a compensating protein rather than repairing the underlying urea cycle defect. By editing GS mRNA to create a de novo protein with a single amino acid change that prevents glutamine-induced proteasomal degradation, we aim to maintain consistent ammonia clearance capacity irrespective of the specific enzyme deficiency in patients with UCD and to reduce ammonia levels in patients with HE. We anticipate a regulatory filing to enable commencement of a first-in-human trial in the second half of 2026.

In November 2025, we announced that KRRO-110 did not reach projected levels of functional protein following a single administration and pivoted to GalNAc delivery for patients with AATD with development candidate nomination expected in the second quarter of 2026. We are developing a next-generation GalNAc-conjugated RNA editing oligonucleotide for the treatment of AATD that has the potential to be disease-modifying and provide a differentiated therapeutic option.

In May 2025, we announced a strategic plan to streamline our operations, including a reduction in workforce by 19%, or 21 positions. In November 2025, we implemented a strategic restructuring to extend cash runway, including a further workforce reduction of approximately 34%. Please see Note 16 to our audited consolidated financial statements included elsewhere in this Annual Report on Form 10-K.

Since inception, we have focused primarily on organizing and staffing our company, business planning, raising capital, securing related intellectual property, and conducting research and development activities for our potential programs and development candidates. Since inception, we have funded our operations primarily through the private placement of our equity securities. To date, we have raised approximately $223.6 million of aggregate gross proceeds from the sale of our convertible preferred stock, $117.3 million from the sale of shares of common stock issued in a private placement that closed immediately

100

prior to the November 2023 business combination, $70.0 million from the April 2024 private placement of shares of our common stock, $5.1 million from sales under our at-the-market offering program, and $85.0 million from the March 2026 private placement.

We have incurred significant operating losses since inception. Our net losses were $117.3 million and $83.6 million for the years ended December 31, 2025 and 2024, respectively. We had an accumulated deficit of $383.8 million as of December 31, 2025. We expect to continue to incur significant and increasing expenses and operating losses and negative operating cash flows for the foreseeable future as we continue our research and development efforts, advance development candidates into and through clinical development, and seek regulatory approvals for our development candidates. Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending on the timing of our preclinical studies, initiation and conduct of any clinical trials, and our expenditures on other research and development activities, including the expansion of our pipeline.

We do not have any development candidates approved for sale and have not generated any revenue from product sales. We will not generate revenue from product sales unless and until we successfully obtain regulatory approval for our development candidates, if ever, and as appropriate, move pipeline candidates into the clinic and complete clinical development. If we obtain regulatory approval for our development candidates and do not enter into third-party commercialization partnerships, we expect to incur significant expenses related to developing commercialization capabilities to support product sales, marketing, manufacturing and distribution activities. As a result, we will need substantial additional funding to support our continuing operations and pursue our development and growth strategy. Until we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of public or private offerings of securities, debt financings or other sources, such as potential collaboration agreements, strategic alliances and licensing arrangements. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed on acceptable terms, or at all. Our failure to raise capital or enter into such agreements as, and when needed, could have a negative effect on our business, results of operations and financial condition.

Recent Developments

At-the-Market Offering Program

In January 2026, we issued 501,861 shares of common stock under our December 2024 at-the-market sales agreement for gross proceeds of $5.1 million, before deducting estimated offering expenses.

March 2026 Private Placement

On March 9, 2026, we entered into a subscription agreement with certain new and existing accredited investors to issue and sell in a private placement an aggregate of 4,501,928 shares of our common stock at a purchase price of $11.11 per share and pre-funded warrants to purchase up to an aggregate of 3,148,836 shares of our common stock (at an exercise price of $0.001 per share) at a price of $11.109 per pre-funded warrant. The private placement, which closed March 10, 2026, resulted in gross proceeds of approximately $85.0 million before deducting placement agent fees and estimated offering expenses.

Financial Operations Overview

Revenue

We have not generated any revenue from product sales, and do not expect to generate any revenue from the sale of products in the near future. During the year ended December 31, 2025 and 2024, we recognized $6.4 million and $2.3 million of collaboration revenue, respectively, which is related to our research collaboration and license agreement with Novo Nordisk. In

101

November 2025, we agreed to a 12 month pause on such collaboration with Novo Nordisk, and accordingly, we do not expect to recognize any material collaboration revenue under such agreement during the 12-month hold period.

For additional information about our revenue recognition policy, see Note 2 and Note 12 to our audited consolidated financial statements included in this Annual Report on Form 10-K.

Operating Expenses

Research and Development Expenses

Research and development expenses consist primarily of costs incurred for our research and development activities, including our discovery of novel genetic medicines and the development of our development candidates, salaries and benefits, and third-party license fees. We expense research and development costs as incurred, which include:

•
employee-related expenses, including salaries, bonuses, benefits, stock-based compensation and other related costs for employees engaged in research and development efforts;

•
expenses incurred under agreements with CROs that conduct our preclinical studies and clinical trials;

•
costs of purchasing lab supplies and non-capital equipment used in our preclinical activities and in manufacturing preclinical study materials, as well as supplies and materials used to manufacture clinical trial materials;

•
costs of outside consultants and contractors engaged in research and development activities, including their fees and travel expenses;

•
payments made under third-party licensing agreements; and

•
direct and allocated expenses for facilities.

Costs for certain activities are recognized based on an evaluation of the progress to completion of specific tasks using data such as information provided to us by our vendors and analyzing the progress of our preclinical studies, clinical trials or other services performed. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are capitalized. The capitalized amounts are expensed as the related goods are delivered or the services are performed. Significant judgment and estimates are made in determining the accrued expense balances and prepaid expense balances at the end of any reporting period.

A large portion of our research and development expenses have been external expenses, which we track on a program-by-program basis following nomination as a development candidate. Our internal research and development expenses are primarily personnel-related expenses, including stock-based compensation expense and facility expenses, mainly including office rent expenses and depreciation expenses. We do not allocate our internal research and development expenses to specific development candidate programs as they are deployed across multiple projects under research and development.

The successful development of our development candidates is highly uncertain. We plan to substantially increase our research and development expenses for the foreseeable future as we continue the development of our candidates, conduct discovery and research activities for our preclinical programs, and expand our pipeline. We cannot determine with certainty the timing of initiation, the duration or the completion costs of current or future preclinical studies and clinical trials of our development candidates due to the inherently unpredictable nature of preclinical and clinical development. Clinical and preclinical development timelines, the probability of success and development costs can differ materially from expectations. We anticipate that we will make determinations as to which lead candidates and development candidates to pursue and how much funding to direct to each on an ongoing basis in response to the results of ongoing and future preclinical studies and clinical trials, regulatory developments and our ongoing assessments as to each development candidate’s commercial potential. Our clinical development costs are expected to increase significantly as we commence clinical trials. We anticipate that our expenses will increase substantially, particularly due to the numerous risks and uncertainties associated with developing development candidates, including the uncertainty of:

•
the scope, rate of progress, and expenses of our ongoing research activities as well as any preclinical studies, clinical trials and other research and development activities;

•
establishing an appropriate safety profile with IND enabling studies;

•
successful enrollment in and completion of clinical trials;

•
whether our development candidates show safety and efficacy in our clinical trials;

•
receipt of marketing approvals from applicable regulatory authorities;

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•
making arrangements with third-party manufacturers;

•
obtaining and maintaining patent and trade secret protection and regulatory exclusivity for our development candidates;

•
commercializing development candidates, if and when approved, whether alone or in collaboration with others; and

•
continued acceptable safety profile of products following any regulatory approval.

Any changes in the outcome of any of these variables with respect to the development of our development candidates in preclinical and clinical development could mean a significant change in the costs and timing associated with the development of these development candidates. We may never succeed in achieving regulatory approval for any of our development candidates. We may obtain unexpected results from our clinical trials. We may elect to discontinue, delay or modify clinical trials of some development candidates or focus on other development candidates. For example, if the FDA, EMA, HREC, TGA or another regulatory authority were to delay the planned start of clinical trials or require us to conduct clinical trials or other testing beyond those that we currently expect or if we experience significant delays in enrollment in any planned clinical trial, we could be required to expend significant additional financial resources and time on the completion of clinical development of that development candidate.

General and Administrative Expenses

General and administrative expenses consist primarily of employee related costs, including salaries, bonuses, benefits, stock-based compensation and other related costs for our executive and administrative functions. General and administrative expenses also include professional services, including legal, finance, accounting, human resources and other consulting fees. General and administrative expenses also include facility costs not otherwise included in research and development expenses.

We anticipate that our general and administrative expenses will decrease or remain flat in the near future to support our current planned research activities and development of our lead candidates and development candidates at current personnel levels. However, should we grow our operations, we anticipate that such personnel-related expenses would increase. We also expect to continue to incur costs associated with being a public company and maintaining controls over financial reporting, including costs of accounting, audit, legal, regulatory, compliance and director and officer insurance costs as well as investor and public relations expenses.

Long-lived Asset Impairment Charges

We determined that indicators of impairment existed during the fourth quarter of 2025 and, as a result, our long-lived assets were reviewed for impairment. We assessed the recoverability of our single enterprise-wide asset group and determined that the assets were not fully recoverable when compared to the future undiscounted cash flows from the asset group. As a result, we estimated the fair value of the asset group, which resulted in a non-cash, long-lived asset impairment charge of $30.9 million in 2025. See Note 3 for further discussion of the impairment analysis.

Restructuring Charges

In May 2025, we announced a strategic plan to streamline our operations, including a workforce reduction of approximately 20%. In connection with the November 2025 announcement regarding KRRO-110, we further implemented a strategic restructuring to reserve resources and extend cash runway, including a reduction in our workforce. Restructuring charges consist primarily of severance and employee benefits costs incurred in relation to our reductions in force.

See Note 16 to our audited consolidated financial statements included in this Annual Report on Form 10-K for further discussion of our restructuring charges.

Other Income, Net

Other income, net primarily consists of interest income earned on money market fund accounts and marketable securities.

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Results of Operations

Comparison of the Years Ended December 31, 2025 and 2024

The following table summarizes our results of operations for the years ended December 31, 2025 and 2024:

Year Ended December 31,

(in thousands)

2025

2024

Change

Collaboration revenue

$

6,392

$

2,271

$

4,121

Operating expenses:

Research and development

65,575

63,636

1,939

General and administrative

28,159

30,545

(2,386

)

Long-lived asset impairment charge

30,886

—

30,886

Restructuring charge

3,627

—

3,627

Total operating expenses

128,247

94,181

34,066

Loss from operations

(121,855

)

(91,910

)

(29,945

)

Other income, net

Other income, net

5,232

8,470

(3,238

)

Total other income, net

5,232

8,470

(3,238

)

Loss before provision for income taxes

(116,623

)

(83,440

)

(33,183

)

Provision for income taxes

(637

)

(141

)

(496

)

Net loss

$

(117,260

)

$

(83,581

)

$

(33,679

)

Collaboration Revenue

During the year ended December 31, 2025 and 2024, we recognized $6.4 million and $2.3 million of collaboration revenue, respectively, from our research collaboration and license agreement with Novo Nordisk. In November 2025, we agreed to a 12 month pause on our collaboration with Novo Nordisk. Accordingly, we do not expect to recognize any material collaboration revenue under such agreement during the 12-month hold period.

Research and Development Expenses

The following table summarizes our research and development expenses for the years ended December 31, 2025 and 2024:

Year Ended December 31,

(in thousands)

2025

2024

Change

Development candidate expenses

    KRRO-110 (AATD) external expenses

$

17,870

$

20,906

$

(3,036

)

    KRRO-121 (UCD) external expenses

5,429

617

4,812

Unallocated research and development expenses

    Other research and pre-development candidate expenses

10,824

12,311

(1,487

)

    Personnel expenses

21,010

18,477

2,533

    Facilities expenses

10,442

11,325

(883

)

Total research and development expenses

$

65,575

$

63,636

$

1,939

104

Research and development expenses were $65.6 million for the year ended December 31, 2025, compared to $63.6 million for the year ended December 31, 2024. The increase was primarily due to the following:

•
a $4.8 million increase in KRRO-121 external expenses, primarily due to exploratory and manufacturing costs; and

•
a $2.5 million increase in personnel-related expenses, primarily due to the expansion of our clinical development function and stock-based compensation;

•
offset by a $3.0 million decrease in KRRO-110 external expenses, primarily due to a reduction in non clinical costs partially offset by an increase in clinical costs for the Phase 1/2a REWRITE clinical trial as it progressed during 2025; and

•
a $1.5 million decrease in other research and pre-development candidate expenses.

General and Administrative Expenses

The following table summarizes our general and administrative expenses for the years ended December 31, 2025 and 2024:

Year Ended December 31,

(in thousands)

2025

2024

Change

Personnel-related expenses

$

14,394

$

13,160

$

1,234

Professional services

7,021

9,640

(2,619

)

Facilities expenses

2,874

3,732

(858

)

Other

3,870

4,013

(143

)

Total general and administrative expenses

$

28,159

$

30,545

$

(2,386

)

General and administrative expenses were $28.2 million for the year December 31, 2025, compared to $30.5 million for the year ended December 31, 2024. The decrease was primarily due to a $2.6 million decrease in professional services expenses, offset by a $1.2 million increase in personnel-related expenses, which was mainly attributable to an increase in stock-based compensation costs.

Long-lived Asset Impairment Charges

Long-lived asset non-cash impairment charges for the year ended December 31, 2025 consisted of $15.0 million and $15.9 million of impairment charges on our operating ROU asset and property and equipment, respectively. We did not incur any impairment charges for the year ended December 31, 2024.

Restructuring Charges

Restructuring charges for the year ended December 31, 2025 consisted of $3.6 million of employee termination benefits related to our workforce reductions in May and November 2025. During the year ended December 31, 2025, all activities related to our May 2025 workforce reduction were completed. The remaining payments related to our November 2025 workforce reduction are expected to be paid by the third quarter of 2026. We did not incur any restructuring charges for the year ended December 31, 2024.

Other Income, Net

Total other income, net was $5.2 million for the year ended December 31, 2025, compared to $8.5 million for the year ended December 31, 2024. The decrease of $3.3 million was primarily due to lower interest income generated from a lower cash, cash equivalent and marketable securities balance in 2025 compared to 2024.

Liquidity and Capital Resources

Sources of Liquidity

Since our inception, we have generated recurring net losses. We have not yet commercialized any products and we do not expect to generate revenue from sales of any products for several years, if at all. Since inception, we have funded our operations primarily through proceeds from the issuance of convertible preferred stock and common stock. To date, we have raised approximately $223.6 million of aggregate gross proceeds from the sale of convertible preferred stock, $117.3 million from the sale of shares of common stock issued in a private placement that closed immediately prior to the November 2023 business combination, $70.0 million from the April 2024 private placement of shares of our common stock, $5.1 million from the January

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2026 sales under our at-the-market offering program, and $85.0 million from the March 2026 private placement. As of December 31, 2025, we had cash, cash equivalents and marketable securities of $85.2 million.

Since inception, we have incurred significant operating losses and, as of December 31, 2025, had an accumulated deficit of $383.8 million. We expect to continue to incur significant expenses, operating losses, and negative operating cash flows for the foreseeable future. In addition, we have not yet commercialized any product and we do not expect to generate revenue from sales of any products for several years, if at all.

In December 2024, we entered into a sales agreement with TD Securities (USA) LLC, or TD Cowen, under which we may, from time to time, issue and sell shares of our common stock having aggregate sales proceeds of up to $100.0 million, in a series of one or more at-the-market equity offerings. As of December 31, 2025, we had not sold any shares of common stock under our at-the-market equity offering program. In January 2026, we issued 501,861 shares of common stock under the at-the-market offering program for gross proceeds of $5.1 million.

As of December 31, 2025, we had cash, cash equivalents and marketable securities of $85.2 million. We expect that our cash, cash equivalents and marketable securities outstanding as of December 31, 2025, together with the net proceeds raised under the January at-the-market offering program sales and March 2026 private placement, will be sufficient to fund our operating expenses and capital expenditure requirements into the second half of 2028. We have based this estimate on assumptions that may prove to be wrong, and we could expend our capital resources sooner than we expect. We may also pursue additional cash resources through public or private equity, collaborations or debt financings. There is no assurance that we will be successful in obtaining sufficient financing on acceptable terms to continue funding our operations.

Funding Requirements

We expect to continue to incur significant expenses, operating losses, and negative operating cash flows for the foreseeable future as we continue our novel genetic medicine discovery efforts, advance our pipeline candidates into the clinic and through clinical trials, seek regulatory approval of our development candidates and pursue commercialization of any approved development candidates. In addition, we expect to continue to incur costs associated with operating as a public company.

Because of the numerous risks and uncertainties associated with research, development and commercialization of our development candidates, we are unable to estimate the exact amount of our working capital requirements.

Our future capital requirements will depend on many factors, including:

•
the scope, progress, results, and costs of discovery, preclinical development, laboratory testing, manufacturing and clinical trials for KRRO-121 and other candidates we may develop;

•
the cost of continuing to build our OPERA platform and discover additional novel genetic medicines;

•
the extent to which we partner our programs, acquire or in-license other lead candidates, development candidates and technologies or enter into additional collaborations;

•
the outcome, timing and cost of meeting regulatory requirements established by the FDA, EMA and other regulatory authorities;

•
the timing and amount of milestone and royalty payments that we are required to make or eligible to receive under any future collaboration and license agreements;

•
any future headcount growth and associated costs, should we expand our research and development efforts;

•
the cost of expanding, maintaining and enforcing our intellectual property portfolio, including filing, prosecuting, defending and enforcing our patent claims and other intellectual property rights;

•
the cost of defending potential intellectual property disputes, including patent infringement actions brought by third parties against us or any of our lead candidates or development candidates;

•
the costs and timing of future commercialization activities, including product manufacturing, marketing, sales and distribution, for any development candidates for which we receive marketing approval;

•
the cost and timing of completion of commercial-scale manufacturing activities;

•
the effect of competing technological and market developments; and

•
the costs of operating as a public company.

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Until such time, if ever, as we can generate substantial product revenues to support our cost structure, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaborations and other similar arrangements. To the extent that we raise additional capital through the sale of equity or convertible securities, the ownership interest of our stockholders will be or could be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our common stockholders. Debt financing and equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise funds through collaborations, or other similar arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or development candidates or grant licenses on terms that may not be favorable to us and/or may reduce the value of our common shares. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product research and development or grant rights to develop and market our development candidates even if we would otherwise prefer to develop and market such development candidates ourselves.

Cash Flows

Comparison of the Years Ended December 31, 2025 and 2024

The following table summarizes our cash flows for the years ended December 31, 2025 and 2024:

Year Ended December 31,

(in thousands)

2025

2024

Net cash used in operating activities

$

(78,561

)

$

(60,074

)

Net cash provided by (used in) investing activities

43,993

(123,347

)

Net cash provided by financing activities

685

69,355

Effect of foreign exchange rate changes

64

(4

)

Net decrease in cash, cash equivalents and restricted cash

$

(33,819

)

$

(114,070

)

Cash Used in Operating Activities

Net cash used in operating activities was $78.6 million for the year ended December 31, 2025, primarily resulted from our net loss of $117.3 million, which was primarily attributable to our research and development activities and our general and administrative expenses, along with changes in our operating assets and liabilities of $4.4 million, offset by $43.1 million of non-cash items, primarily the $30.9 million impairment of long-lived assets.

Net cash used in operating activities was $60.1 million for the year ended December 31, 2024, primarily resulted from our net loss of $83.6 million, which was primarily attributable to our research and development activities and our general and administrative expenses, along with changes in our operating assets and liabilities of $13.6 million, offset by $9.9 million of non-cash items.

Cash Provided by (Used in) Investing Activities

Net cash provided by investing activities was $44.0 million for the year ended December 31, 2025 and consisted primarily of the proceeds from maturities of marketable securities, offset by purchase of marketable securities and the purchase of property and equipment.

Net cash used in investing activities was $123.3 million for the year ended December 31, 2024 and consisted primarily of the purchase of marketable securities and the purchase of property and equipment, offset by proceeds from maturities of marketable securities.

Cash Provided by Financing Activities

Net cash provided by financing activities was $0.7 million for the year ended December 31, 2025 and consisted of proceeds from exercises of stock options.

Net cash provided by financing activities was $69.4 million for the year ended December 31, 2024 and consisted of net proceeds from the April 2024 private placement and proceeds from exercises of stock options.

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Critical Accounting Policies and Estimates

Our management’s discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles in the United States, or GAAP. The preparation of these consolidated financial statements requires us to make judgments and estimates that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities in our financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions. On an ongoing basis, we evaluate our judgments and estimate in light of changes in circumstances, facts, and experience. The effects of material revisions in estimates, if any, will be reflected in the consolidated financial statements prospectively from the date of change in estimates.

While our significant accounting policies are described in more detail in Note 2 to our audited consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K, we believe that the following accounting policy is most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Long-lived Assets

We periodically evaluate long-lived assets for impairment when changes in circumstances or the occurrence of certain events indicate the carrying amount of an asset or asset group may not be recoverable. Identifying and assessing whether impairment indicators exist, or if events or changes in circumstances have occurred, including an adverse change in legal factors or in the business climate that could affect the value of the long-lived asset (group); an adverse change in the extent or manner in which the long-lived asset (group) is used or is expected to be used, or in its physical condition; and current or forecasted operating or cash flow losses that demonstrate continuing losses associated with the use of the long-lived asset (group), requires judgment. Additionally, grouping assets requires judgment. Changes in judgment used could materially affect our financial condition and results of operations.

We determined that indicators of impairment existed during the fourth quarter of 2025 and, as a result, reviewed our long-lived assets for impairment. We assessed the recoverability of our single enterprise-wide asset group and determined that the assets were not fully recoverable when compared to the future undiscounted cash flows from the asset group. As a result, we estimated the fair value of the asset group which resulted in a non-cash, long-lived asset impairment charge of $30.9 million in 2025.

See Note 3 to our audited consolidated financial statements included in this Annual Report on Form 10-K for further discussion of our impairment analysis.

Contractual Obligations and Other Commitments

Our contractual obligations and commitments relate primarily to our operating leases and non-cancelable purchase obligations under agreements with various research and development organizations and suppliers in the ordinary course of business. See Note 13, "Commitments and Contingencies" to our audited consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K.

Recent Accounting Pronouncements

A description of recently issued and recently adopted accounting pronouncements applicable to our financial position and results of operations is included in Note 2 to our audited consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K.

Smaller Reporting Company Status

We are a “smaller reporting company” as defined in Item 10(f)(1) of Regulation S-K. Smaller reporting companies may take advantage of certain reduced disclosure obligations, including, among other things, providing only two years of audited financial statements. We will remain a smaller reporting company until the last day of the fiscal year in which (i) the market value of our common stock held by non-affiliates exceeds $250 million as of the prior June 30, or (ii) our annual revenues exceed $100

108

million during such completed fiscal year and the market value of our common stock held by non-affiliates exceeds $700 million as of the prior June 30.