Korro Bio, Inc.
For the period ended Sep 30, 2025. Filed Nov 12, 2025.
View on SEC.govAbout this filing
A company's report for each of its first three quarters. The financial statements are not audited. It shows how the business has moved since the last annual report, and what management says changed.
Sep 30, 2025 · Filed Nov 12, 2025
KRRO$14.75+0.1%Stored close · as of Nov 6, 2026
What changed in Management’s Discussion and Analysis?
Read the current filingPrevious report: 10-Q
Period ended 2025-06-30; filed 2025-08-12.
0000950170-25-106912
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of OperationsCurrent report: 10-Q
Period ended 2025-09-30; filed 2025-11-12.
0001193125-25-277572
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of OperationsThe baseline is this issuer’s latest earlier reporting period of the same form that was filed before the current report. A previous 10-Q is a different quarter, not a year-over-year comparison. Amendments are excluded.
Compared 102 previous paragraphs and 123 current paragraphs.
70 unchanged; 27 reworded; 24 added; 4 removed; 1 previous and 2 current paragraphs rearranged.
Tables are not compared: 4 previous and 4 current tables excluded. Dates, whitespace, punctuation and numbering changes are ignored; changes to financial figures remain significant.
A changed paragraph is not evidence that risk increased or decreased. An unchanged paragraph does not establish that risk stayed the same.
Added paragraphs (24)
Current report
We have investigated KRRO-110 as a treatment for AATD where, using our proprietary RNA editing approach, we aimed to repair a pathogenic variant on RNA. KRRO-110 did not reach projected levels of functional protein following a single administration as of the data cutoff date, and we are now pivoting to GalNAc delivery for AATD and expect to nominate a development candidate in 2025. In January 2025, we announced dosing of the first participants in our REWRITE clinical program investigating KRRO-110 as a treatment for AATD. The REWRITE clinical trial is a two-part single and multiple-dose escalating study evaluating the safety and tolerability of KRRO-110, including healthy adults and clinically stable AATD patients with the PiZZ genotype. We have completed all six planned single ascending dose, or SAD, healthy volunteer, or HV, cohorts. Each HV cohort consisted of six participants, with four receiving active drug and two receiving placebo. Doses of KRRO-110 tested in the HVs (n=24) include 0.04, 0.1, 0.2, 0.4, 0.8 and 1.2 mg/kg, with the primary objective to evaluate safety and tolerability. KRRO-110 is currently being evaluated in two AATD patient cohorts at 0.6 mg/kg (n=3) and 0.8 mg/kg (n=4), with seven patients dosed. The AATD patient cohorts are open label with up to four patients in each cohort. There are currently no plans to complete additional SAD patient cohorts for KRRO-110. We are evaluating the totality of the clinical data to evaluate the next steps, if any, for KRRO-110 in the multiple-ascending dose, or MAD, portion of the REWRITE clinical trial. Key findings of the REWRITE clinical trial include:
Current report
KRRO-110 Safety Observations (as of the November 6, 2025 Data Cutoff Date):
Current report
Mild-to-moderate infusion-related reactions, or IRRs, observed in two healthy volunteers at the highest dose of 1.2 mg/kg, two AATD patients at 0.6 mg/kg, and two AATD patients at 0.8 mg/kg.
Current report
All IRRs resolved within 24 hours post KRRO-110 dosing; intervention was limited to antipyretics and antihistamines.
Current report
KRRO-110 safety profile is consistent with Lipid Nanoparticle, or LNP, infusion-related class effects.
Current report
KRRO-110 Pharmacodynamic and Pharmacokinetic Observations (as of the November 6, 2025 Data Cutoff Date):
Current report
Across five AATD patients in the two SAD cohorts evaluable with turbidimetry, the greatest peak total AAT protein was approximately 10 µM and the greatest increase of total AAT protein from baseline was approximately 3 µM. The total AAT protein levels following single-dose administration did not reach the protective threshold of 11 µM.
Current report
In three of the AATD patients dosed with 0.8 mg/kg evaluable with LC/MS, functional M-AAT protein was observed in each of the patients following administration of KRRO-110. The greatest increase of M-AAT protein from baseline observed at any time point was approximately 2 µM. Functional M-AAT protein lasted up to four weeks for the first patient evaluable with LC/MS, consistent with durability of editing and endogenous M-AAT protein half-life.
Current report
Pharmacokinetic, or PK, differences in the components of KRRO-110 in plasma were observed between HV and AATD patients, with apparent faster disassociation of KRRO-110, suggesting variability of this formulation in AATD patients compared to HV following a single dose.
Current report
No evidence of bystander editing observed to date, suggesting high specificity, based on LC/MS data on M-AAT and Z-AAT.
Current report
KRRO-110 Regulatory Milestones Validate OPERA Platform Potential:
Current report
First-ever RNA editing technology to receive investigational new drug application, or IND, clearance by the U.S. Food and Drug Administration, or FDA, to our knowledge.
Current report
Fast Track designation granted by the FDA.
Current report
Orphan Drug Designation granted by both the FDA and European Medicines Agency.
Current report
We recently nominated our second development candidate, KRRO-121, for the potential treatment of UCD and HE. KRRO-121 is a GalNAc-conjugated oligonucleotide that will be administered subcutaneously to create de novo protein variants and designed to stabilize a critical enzyme involved in reducing ammonia levels. We plan to submit a regulatory filing of first-in-human trial for KRRO-121 in the second half of 2026. We are also prioritizing other high-potential GalNAc-conjugated programs targeting the liver, including an AATD program and programs for subcutaneous delivery in cardiometabolic indications. We plan to nominate a development candidate for our GalNAc-conjugated AATD program in 2026.
Current report
In November 2025, we implemented a strategic restructuring to extend cash runway, including a further workforce reduction of approximately 34%. We estimate that we will incur one-time restructuring charges of approximately $2.4 million including employee severance, benefits and related termination costs, the majority of which we expect to recognize during the three months ended December 31, 2025.
Current report
agreement during the 12-month hold period.
Current report
Research and development expenses were $13.8 million for the three months ended September 30, 2025, compared to $16.0 million for the three months ended September 30, 2024. The decrease was primarily due to the following:
Current report
a $2.0 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 continued to progress; and
Current report
offset by a $0.9 million increase in personnel-related expenses, primarily due to the expansion of our clinical development function.
Current report
Research and development expenses were $54.6 million for the nine months ended September 30, 2025, compared to $46.7 million for the nine months ended September 30, 2024. The increase was primarily due to the following:
Current report
Comparison of the Nine Months Ended September 30, 2025 and 2024
Current report
Net cash used in operating activities was $60.9 million for the nine months ended September 30, 2025, primarily resulted from our net loss of $67.2 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 $3.0 million, offset by $9.3 million of non-cash items.
Current report
Net cash used in operating activities was $52.6 million for the nine months ended September 30, 2024, primarily resulted from our net loss of $62.4 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 $2.4 million, offset by $7.4 million of non-cash items.
Removed paragraphs (4)
Previous report
We plan to announce a development candidate for our rare metabolic disorder program by the end of 2025. This candidate will be administered subcutaneously and targeted to the liver using GalNAc to create de novo protein variants designed to have therapeutic effect.
Previous report
Comparison of the Six Months Ended June 30, 2025 and 2024
Previous report
Net cash used in operating activities was $43.7 million for the six months ended June 30, 2025, which consisted of $49.2 million of net loss, $6.2 million of non-cash adjustments to net loss and a decrease of $0.7 million in the net change in operating assets and liabilities. Non-cash adjustments primarily consisted of $3.7 million of stock-based compensation expenses and $2.5 million of depreciation expenses. The decrease in net assets consisted primarily of a $1.0 million decrease in deferred revenue and a $0.6 million decrease in accounts receivable in connection with the collaboration arrangement with Novo Nordisk, a $0.5 million decrease in accrued expenses and other liabilities, and a $0.1 million decrease in operating lease liabilities, partially offset by a $1.1 million increase in accounts payable mainly due to the timing of vendor payment and, a $0.4 million increase in prepaid expenses and other current assets, and a $0.4 million increase in other non-current assets.
Previous report
Net cash used in operating activities was $36.5 million for the six months ended June 30, 2024, which consisted of $41.4 million of net loss, $5.4 million of non-cash adjustments to net loss and an increase of $0.5 million in the net change in operating assets and liabilities. Non-cash adjustments primarily consisted of $2.3 million of amortization of operating lease right of use assets, $1.8 million of stock-based compensation expenses, and $1.4 million of depreciation expenses. The increase in net assets consisted primarily of a $5.3 million increase in operating lease liabilities mainly due to the receipts of tenant improvement allowance from the landloard during the six months ended June 30, 2024, whereas no equivalent allowance was received during the same period of 2025. The increase also includes a $1.4 million increase in prepaid expenses and other current assets, offset by a $4.1 million decrease in accrued expenses and other liabilities and a $0.5 million decrease in accounts payable mainly driven by projects status and timing of vendor billing and vendor payments.
Reworded paragraphs (27)
Previous wording
The versatility of RNA editing combined with our RNA platform broadens the therapeutic target space significantly. While our approach can be used to repair pathogenic single nucleotide variants, or SNVs, as demonstrated by our most advanced clinical-stage program, our AATD product candidate KRRO-110, we can also engineer de novo SNVs and change amino acids on proteins to endow them with desired properties while preserving their broader functional capabilities, as exemplified by three of our other programs (an undisclosed rare metabolic disorder, amyotrophic lateral sclerosis, and pain). In preclinical studies, we have demonstrated that single RNA changes can disrupt protein-protein interactions, prevent protein aggregation, selectively modulate ion channels and activate kinases. These modification approaches can unlock validated target classes that have historically been difficult to drug, enabling us to pursue a broad range of diseases traditionally out-of-scope for other genetic medicine approaches and current traditional drug modalities.
Current wording
The versatility of RNA editing combined with our RNA platform broadens the therapeutic target space significantly. While our approach can be used to repair pathogenic single nucleotide variants, or SNVs, we can also engineer de novo SNVs and change amino acids on proteins to endow them with desired properties while preserving their broader functional capabilities, as exemplified by KRRO-121, our recently announced product candidate targeting the liver via GalNAc, initially to treat patients with urea cycle disorders, or UCD, and the potential to expand into patients with hepatic encephalopathy, or HE. In preclinical studies, we have demonstrated that single RNA changes can disrupt protein-protein interactions, prevent protein aggregation, selectively modulate ion channels and activate kinases. These modification approaches can unlock validated target classes that have historically been difficult to drug, enabling us to pursue a broad range of diseases traditionally out-of-scope for other genetic medicine approaches and current traditional drug modalities.
Previous wording
Our clinical-stage development program is investigating KRRO-110 as a treatment for AATD where, using our proprietary RNA editing approach, we are repairing a pathogenic variant on RNA. KRRO-110 has the potential to be disease-modifying and provide a differentiated therapeutic option. In January 2025, we announced dosing of the first participants in our REWRITE clinical program investigating KRRO-110 as a treatment for AATD. REWRITE is a two-part single and multiple dose-escalating Phase 1/2a clinical trial that will evaluate the safety and tolerability of KRRO-110 in up to 64 participants, including healthy adults and clinically stable AATD patients with the PiZZ genotype. Secondary and exploratory endpoints include pharmacokinetic and pharmacodynamic parameters that will guide optimal dose selection for later stage studies. We have completed dosing of over 80% of planned healthy volunteers across multiple single ascending dose cohorts, including dose levels that are expected to be pharmacologically relevant in PiZZ patients. We have not observed any treatment emergent serious adverse events or dose limiting toxicities as of the date of this Quarterly Report on Form 10-Q. In May 2025, we announced approval to expand our Phase 1/2a REWRITE clinical trial of KRRO-110 for AATD into New Zealand, and we continue to progress enrollment, site activation and expansion into other geographies beyond Australia and New Zealand, including the United States. In March 2025 and July 2025, we announced that the U.S. Food and Drug Administration, or FDA, and the European Medicines Agency, or EMA, respectively, granted orphan drug designation to KRRO-110 for the treatment of AATD. Interim data from single ascending doses in healthy volunteers and AATD patients is expected in the second half of 2025, and completion of the REWRITE Phase 1/2a trial, including Part 2 (multiple ascending doses in individuals with AATD), is anticipated in 2026. Based on the preclinical data, we believe KRRO-110 has best-in-class potential for the treatment of AATD. However, KRRO-110 is in early clinical development and there is no guarantee that it will be successful.
Current wording
No dose-limiting toxicities or treatment emergent serious adverse events observed.
Previous wording
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 prior to the November 2023 business combination and $70.0 million from the April 2024 private placement of shares of our common stock.
Current wording
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 product 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 prior to the November 2023 business combination and $70.0 million from the April 2024 private placement of shares of our common stock.
Previous wording
We have incurred significant operating losses since inception. Our net losses were $49.2 million and $41.4 million for the six months ended June 30, 2025 and 2024, respectively. We had an accumulated deficit of $315.7 million as of June 30, 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 product candidates through clinical development, and seek regulatory approvals for our pipeline 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.
Current wording
We have incurred significant operating losses since inception. Our net losses were $67.2 million and $62.4 million for the nine months ended September 30, 2025 and 2024, respectively. We had an accumulated deficit of $333.8 million as of September 30, 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 product candidates through clinical development, and seek regulatory approvals for our pipeline 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.
Previous wording
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 six months ended June 30, 2025, we recognized $4.0 million of collaboration revenue, which is related to our September 2024 research collaboration and license agreement with Novo Nordisk. During the six months ended June 30, 2024, we recognized no collaboration revenue.
Current wording
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 nine months ended September 30, 2025, we recognized $5.1 million of collaboration revenue, which is related to our September 2024 research collaboration and license agreement with Novo Nordisk. During the nine months ended September 30, 2024, we recognized no collaboration revenue. 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
Previous wording
For additional information about our revenue recognition policy and our collaboration and license agreement with Novo Nordisk, see Note 11 in the condensed consolidated financial statements included in this Quarterly Report.
Current wording
For additional information about our revenue recognition policy and our collaboration and license agreement with Novo Nordisk, which is now paused, see Note 11 and Note 17 in the condensed consolidated financial statements included in this Quarterly Report.
Previous wording
Any changes in the outcome of any of these variables with respect to the development of our product candidates in preclinical and clinical development could mean a significant change in the costs and timing associated with the development of these product candidates. We may never succeed in achieving regulatory approval for any of our product candidates. We may obtain unexpected results from our clinical trials. We may elect to discontinue, delay or modify clinical trials of some product candidates or focus on other product candidates. For example, if the FDA, EMA, HREC, Therapeutic Goods Administration, or TGA, the Health and Disability Ethics Committees, or HDEC, 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 product candidate.
Current wording
Any changes in the outcome of any of these variables with respect to the development of our product candidates in preclinical and clinical development could mean a significant change in the costs and timing associated with the development of these product candidates. We may never succeed in achieving regulatory approval for any of our product candidates. We may obtain unexpected results from our clinical trials. We may elect to discontinue, delay or modify clinical trials of some product candidates or focus on other product candidates. For example, if the FDA, EMA, the Human Research Ethics Committee, or HREC, Therapeutic Goods Administration, or TGA, the Health and Disability Ethics Committees, or HDEC, 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 product candidate.
Previous wording
Comparison of the Three and Six Months Ended June 30, 2025 and 2024
Current wording
Comparison of the Three and Nine Months Ended September 30, 2025 and 2024
Previous wording
The following table summarizes our results of operations for the three and six months ended June 30, 2025 and 2024:
Current wording
The following table summarizes our results of operations for the three and nine months ended September 30, 2025 and 2024:
Previous wording
During the three and six months ended June 30, 2025, we recognized $1.5 million and $4.0 million, respectively, of collaboration revenue from our research collaboration and license agreement with Novo Nordisk. During the three and six months ended June 30, 2024, we recognized no collaboration revenue.
Current wording
During the three and nine months ended September 30, 2025, we recognized $1.1 million and $5.1 million, respectively, of collaboration revenue from our research collaboration and license agreement with Novo Nordisk. During the three and nine months ended September 30, 2024, we recognized no collaboration revenue. 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.
Previous wording
The following table summarizes our research and development expenses for the three and six months ended June 30, 2025 and 2024:
Current wording
The following table summarizes our research and development expenses for the three and nine months ended September 30, 2025 and 2024:
Previous wording
Research and development expenses were $21.0 million for the three months ended June 30, 2025, compared to $17.1 million for the three months ended June 30, 2024. The increase was primarily due to a $2.4 million increase in other research and pre-development candidate expenses as we furthered development of our rare metabolic disorders program, a $2.2 million increase in personnel-related expenses mainly driven by an increase in headcount prior to the May 2025 workforce reduction, increased average payroll costs per headcount to support our research and clinical development function, and one-time severance charges related to the workforce reduction, offset by a $0.5 million decrease in KRRO-110 external expenses.
Current wording
a $0.7 million decrease in other research and pre-development candidate expenses;
Previous wording
Research and development expenses were $40.8 million for the six months ended June 30, 2025, compared to $30.7 million for the six months ended June 30, 2024. The increase was primarily due to a $3.3 million increase in KRRO-110 external expenses, which was attributable to a $2.8 million increase in clinical trial expenses in 2025 for the Phase 1/2a REWRITE clinical trial and a $0.5 million net increase in development milestone under our collaboration and license agreement with Genevant Sciences GmbH. A portion of the increase was also due to a $3.5 million increase in personnel-related expenses mainly driven by an increase in headcount prior to the May 2025 workforce reduction, increased average payroll costs per headcount to support our research and clinical development function and one-time severance charges related to the workforce reduction, and a $3.4 million increase in other research and pre-development candidate expenses as we furthered development of our rare metabolic disorders program.
Current wording
a $1.3 million increase in KRRO-110 external expenses, primarily to an increase in clinical trial expenses in 2025 for the Phase 1/2a REWRITE clinical trial, partially offset by a reduction in non clinical costs, and a $0.5 million net increase in development milestone under our collaboration and license agreement with Genevant Sciences GmbH.
Previous wording
The following table summarizes our general and administrative expenses for the three and six months ended June 30, 2025 and 2024:
Current wording
The following table summarizes our general and administrative expenses for the three and nine months ended September 30, 2025 and 2024:
Previous wording
General and administrative expenses were $7.6 million for the three months ended June 30, 2025, compared to $7.0 million for the three months ended June 30, 2024. The increase was primarily due to a $1.0 million increase in personnel-related expenses, which was attributable to a $0.6 million increase in stock-based compensation costs and a $0.4 million increase in severance costs related to the May 2025 workforce reduction, offset by a $0.4 million decrease in professional services.
Current wording
General and administrative expenses were $6.5 million for the three months ended September 30, 2025, compared to $7.3 million for the three months ended September 30, 2024. The decrease was primarily due to a $0.7 million decrease in professional services expenses.
Previous wording
General and administrative expenses were $15.5 million for the six months ended June 30, 2025, compared to $14.9 million for the six months ended June 30, 2024. The increase was primarily due to a $1.7 million increase in personnel-related expenses, which was mainly attributable to a $1.1 million increase in stock-based compensation costs and a $0.4 million increase in severance costs related to the May 2025 workforce reduction, offset by a $1.1 million decrease in professional services.
Current wording
General and administrative expenses were $22.0 million for the nine months ended September 30, 2025, compared to $22.2 million for the nine months ended September 30, 2024. The decrease was primarily due to a $1.8 million decrease in professional services expenses, offset by a $1.9 million increase in personnel-related expenses, which was mainly attributable to an increase in stock-based compensation costs and severance costs related to the May 2025 workforce reduction.
Previous wording
Total other income, net was $1.4 million for the three months ended June 30, 2025, compared to $2.3 million for the three months ended June 30, 2024. The decrease of $0.9 million was primarily due to lower interest income generated from a lower cash, cash equivalent and marketable securities balance as of June 30, 2025.
Current wording
Total other income, net was $1.2 million for the three months ended September 30, 2025, compared to $2.3 million for the three months ended September 30, 2024. The decrease of $1.1 million was primarily due to lower interest income generated from a lower cash, cash equivalent and marketable securities balance as of September 30, 2025.
Previous wording
Total other income, net was $3.1 million for the six months ended June 30, 2025, compared to $4.2 million for the six months ended June 30, 2024. The decrease of $1.1 million was primarily due to lower interest income generated from a lower cash, cash equivalent and marketable securities balance as of June 30, 2025.
Current wording
Total other income, net was $4.2 million for the nine months ended September 30, 2025, compared to $6.5 million for the nine months ended September 30, 2024. The decrease of $2.3 million was primarily due to lower interest income generated from a lower cash, cash equivalent and marketable securities balance as of September 30, 2025.
Previous wording
Since our inception, we have generated recurring net losses. 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. 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 and $70.0 million from the April 2024 private placement of shares of our common stock. As of June 30, 2025, we had cash, cash equivalents and marketable securities of $119.6 million.
Current wording
Since our inception, we have generated recurring net losses. 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. 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 and $70.0 million from the April 2024 private placement of shares of our common stock. As of September 30, 2025, we had cash, cash equivalents and marketable securities of $102.5 million.
Previous wording
Since inception, we have incurred significant operating losses and, as of June 30, 2025, had an accumulated deficit of $315.7 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.
Current wording
Since inception, we have incurred significant operating losses and, as of September 30, 2025, had an accumulated deficit of $333.8 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.
Previous wording
As of June 30, 2025, we had cash, cash equivalents and marketable securities of $119.6 million. We expect that our cash, cash equivalents and marketable securities outstanding as of June 30, 2025 will be sufficient to fund our operating expenses and capital expenditure requirements into 2027. 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.
Current wording
As of September 30, 2025, we had cash, cash equivalents and marketable securities of $102.5 million. We expect that our cash, cash equivalents and marketable securities outstanding as of September 30, 2025 will be sufficient to fund our operating expenses and capital expenditure requirements into the second half of 2027. 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.
Previous wording
the scope, progress, results, and costs of discovery, preclinical development, laboratory testing, manufacturing and clinical trials for KRRO-110 and other product candidates we may develop;
Current wording
the scope, progress, results, and costs of discovery, preclinical development, laboratory testing, manufacturing and clinical trials for KRRO-121, a GalNAc-conjugated candidate for AATD, and other product candidates we may develop;
Previous wording
The following table summarizes our cash flows for the six months ended June 30, 2025 and 2024:
Current wording
The following table summarizes our cash flows for the nine months ended September 30, 2025 and 2024:
Previous wording
Net cash provided by investing activities was $21.5 million for the six months ended June 30, 2025 and consisted primarily of $32.9 million of proceeds from maturities of marketable securities, offset by $11.2 million of purchases of marketable securities and $0.2 million of purchase of property and equipment.
Current wording
Net cash provided by investing activities was $29.1 million for the nine months ended September 30, 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.
Previous wording
Net cash used in investing activities was $108.0 million for the six months ended June 30, 2024 and consisted primarily of $96.4 million of purchase of marketable securities and $11.6 million of purchases of property and equipment.
Current wording
Net cash used in investing activities was $120.6 million for the nine months ended September 30, 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.
Previous wording
Net cash provided by financing activities was $0.2 million for the six months ended June 30, 2025 and consisted primarily of proceeds from exercises of stock options.
Current wording
Net cash provided by financing activities was $0.3 million for the nine months ended September 30, 2025 and consisted of proceeds from exercises of stock options.
Previous wording
Net cash provided by financing activities was $67.7 million for the six months ended June 30, 2024 and consisted primarily of net proceeds from the April 2024 private placement of shares of our common stock.
Current wording
Net cash provided by financing activities was $68.4 million for the nine months ended September 30, 2024 and consisted primarily of net proceeds from the April 2024 private placement.
Rearranged current paragraphs (2)
Current report — wording carried from elsewhere
a $4.3 million increase in personnel-related expenses, primarily due to an increase in headcount prior to the May 2025 workforce reduction, the expansion of our clinical development function and one-time severance charges related to the May 2025 workforce reduction;
Current report — wording carried from elsewhere
a $2.7 million increase in other research and pre-development candidate expenses as we furthered development of KRRO-121; and
Rearranged previous paragraphs (1)
Previous report — wording carried elsewhere
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 product candidates.