Core Insights - Premarket trading is showing notable activity with significant price movements indicating potential opportunities for traders before the market opens [1] Premarket Gainers - Cidara Therapeutics, Inc. (CDTX) is up 91% at $203.18 - Binah Capital Group, Inc. (BCG) is up 45% at $2.07 - Invivyd, Inc. (IVVD) is up 42% at $2.52 - Omeros Corporation (OMER) is up 15% at $7.25 - The Oncology Institute, Inc. (TOI) is up 12% at $3.47 - AlphaVest Acquisition Corp (ATMV) is up 11% at $7.99 - ARB IOT Group Limited (ARBB) is up 7% at $7.31 - Hyperion DeFi, Inc. (HYPD) is up 6% at $5.27 - TruGolf Holdings, Inc. (TRUG) is up 6% at $2.02 - Boqii Holding Limited (BQ) is up 5% at $2.24 [3] Premarket Losers - TSS, Inc. (TSSI) is down 40% at $9.12 - StubHub Holdings, Inc. (STUB) is down 20% at $15.02 - ESS Tech, Inc. (GWH) is down 20% at $3.38 - Red Cat Holdings, Inc. (RCAT) is down 17% at $6.38 - WhiteFiber, Inc. (WYFI) is down 15% at $16.81 - New Era Energy & Digital, Inc. (NUAI) is down 13% at $3.66 - NET Power Inc. (NPWR) is down 11% at $2.62 - Korro Bio, Inc. (KRRO) is down 9% at $5.90 - Anavex Life Sciences Corp. (AVXL) is down 8% at $5.20 - Interactive Strength Inc. (TRNR) is down 5% at $2.47 [4]

Core Insights - Korro Bio, Inc. (NASDAQ:KRRO) is experiencing a significant decline in stock price, down 80% to $6.27, with a trading volume of 6.68 million shares compared to the average of 1.42 million shares [1][8] - The company provided an update on its Phase 1/2a REWRITE clinical trial for KRRO-110, which targets alpha-1 antitrypsin deficiency (AATD) [1][2] - KRRO-110 successfully generated functional M-AAT protein in AATD patients, but the protein levels achieved were below preclinical projections [2][3] Clinical Trial Results - In a study involving five AATD patients, the peak total AAT protein reached approximately 10 µM, with a maximum increase from baseline of about 3 µM [3] - The total AAT protein levels did not meet the protective threshold of 11 µM, although no serious adverse events were reported [3] Strategic Restructuring - The company is implementing a strategic restructuring that includes a workforce reduction of approximately 34% to focus on generating clinical data and advancing liver-targeted programs [4][6] - This restructuring is expected to extend the company's cash runway into the second half of 2027, with cash and marketable securities reported at $102.5 million [6] Future Development Plans - Korro has nominated KRRO-121 as the next development candidate for hyperammonemia, with regulatory filing anticipated in the second half of 2026 [5] - The company amended its collaboration agreement with Novo Nordisk, establishing a 12-month pause to reassess the current research program [5] Analyst Commentary - William Blair downgraded Korro shares from Outperform to Market Perform, citing concerns over the non-competitive clinical profile of KRRO-110 despite the validation of ADAR-mediated editing [7] - The analyst expressed continued interest in Korro's expansion into urea cycle disorders with KRRO-121 but noted the company's shift back to a preclinical stage [7]

Core Insights - Korro Bio, Inc. reported a quarterly loss of $1.92 per share, which was better than the Zacks Consensus Estimate of a loss of $2.61, representing an earnings surprise of +26.44% [1] - The company generated revenues of $1.09 million for the quarter ended September 2025, missing the Zacks Consensus Estimate by 27.33%, compared to zero revenues a year ago [2] - The stock has underperformed the market, losing about 13.8% since the beginning of the year, while the S&P 500 gained 16.4% [3] Earnings Outlook - The current consensus EPS estimate for the upcoming quarter is -$2.42 on revenues of $1.5 million, and for the current fiscal year, it is -$10.26 on revenues of $4.84 million [7] - The estimate revisions trend for Korro Bio, Inc. was mixed ahead of the earnings release, resulting in a Zacks Rank 3 (Hold) for the stock, indicating expected performance in line with the market [6] Industry Context - The Medical - Drugs industry, to which Korro Bio, Inc. belongs, is currently in the top 32% of over 250 Zacks industries, suggesting a favorable outlook compared to the bottom 50% [8] - Another company in the same industry, Nutriband Inc. (NTRB), is expected to report a quarterly loss of $2.13 per share, with revenues projected at $0.68 million, reflecting a year-over-year increase of 4.6% [9]

Financial Performance - The company reported a net loss of $67.2 million for the nine months ended September 30, 2025, compared to a net loss of $62.4 million for the same period in 2024, with an accumulated deficit of $333.8 million as of September 30, 2025[101]. - The net loss for the three months ended September 30, 2025, was $18.1 million, an improvement from a loss of $21.0 million in 2024, while the nine-month net loss was $67.2 million compared to $62.4 million in 2024[126]. - The company expects to continue incurring significant expenses and operating losses for the foreseeable future as it advances its pipeline candidates[129]. Revenue and Collaboration - The company recognized $5.1 million in collaboration revenue during the nine months ended September 30, 2025, related to a research collaboration with Novo Nordisk, with no collaboration revenue recognized in the same period of 2024[105]. - Collaboration revenue for the three months ended September 30, 2025, was $1.1 million, and for the nine months, it was $5.1 million, compared to no collaboration revenue in the same periods of 2024[118]. - A 12-month pause on collaboration with Novo Nordisk was agreed upon in November 2025, leading to no expected material collaboration revenue during this period[118]. - The company has not generated any revenue from product sales and does not expect to do so in the near future, relying on financing through public or private offerings and collaboration agreements[102]. Expenses and Costs - Research and development expenses decreased to $13.8 million for the three months ended September 30, 2025, from $16.0 million in 2024, while for the nine months, expenses increased to $54.6 million from $46.7 million[120]. - General and administrative expenses were $6.5 million for the three months ended September 30, 2025, down from $7.3 million in 2024, and for the nine months, they were $22.0 million compared to $22.2 million in 2024[121]. - The company has incurred significant operating losses since inception and expects to continue incurring significant and increasing expenses and operating losses for the foreseeable future as it advances product candidates through clinical development[101]. Cash Flow and Financing - As of September 30, 2025, the company had cash, cash equivalents, and marketable securities totaling $102.5 million, expected to fund operations into the second half of 2027[128]. - Net cash used in operating activities for the nine months ended September 30, 2025, was $60.9 million, compared to $52.6 million in 2024[133]. - Net cash used in investing activities was $29.1 million for the nine months ended September 30, 2025, mainly from proceeds of marketable securities maturities[136]. - Net cash provided by financing activities was $0.3 million for the nine months ended September 30, 2025, consisting of proceeds from exercises of stock options[138]. - The company has raised approximately $223.6 million from the sale of convertible preferred stock and $117.3 million from common stock sales since inception[100]. Strategic Initiatives - The company implemented a strategic restructuring in November 2025, including a workforce reduction of approximately 34%, with estimated one-time restructuring charges of about $2.4 million[99]. - The company plans to submit a regulatory filing for the first-in-human trial of KRRO-121 in the second half of 2026, targeting urea cycle disorders and hepatic encephalopathy[97]. - KRRO-110 did not reach projected levels of functional protein following a single administration, and the company is pivoting to GalNAc delivery for AATD, expecting to nominate a development candidate in 2025[95]. Designations and Risk - The company has received Fast Track designation and Orphan Drug Designation from the FDA for its RNA editing technology, which is the first to receive investigational new drug application clearance[103]. - The company is classified as a "smaller reporting company," allowing for reduced disclosure obligations[143]. - The company has minimal exposure to foreign currency risk due to short transaction durations[146]. - An immediate 10% change in market interest rates would not materially affect the fair market value of cash or cash equivalents[145].

Financial Performance - Korro ended Q3 2025 with $102.5 million in cash, cash equivalents, and marketable securities, down from $163.1 million at the end of 2024, extending cash runway into the second half of 2027[12] - Korro reported a net loss of $18.1 million for Q3 2025, an improvement from a net loss of $21.0 million in Q3 2024[15] - Net loss for the three months ended September 30, 2025, was $18.06 million, compared to a net loss of $20.99 million for the same period in 2024[24] - Total operating expenses for the three months ended September 30, 2025, were $20.33 million, a decrease of 13% from $23.29 million in the same period of 2024[24] - The comprehensive loss for the nine months ended September 30, 2025, was $67.27 million, compared to $61.81 million for the same period in 2024[24] - Other income for the three months ended September 30, 2025, was $1.18 million, compared to $2.28 million for the same period in 2024[24] Revenue and Expenses - Collaboration revenue for Q3 2025 was $1.1 million, compared to no collaboration revenue in Q3 2024, attributed to the partnership with Novo Nordisk[13] - G&A expenses were $6.5 million in Q3 2025, down from $7.3 million in Q3 2024, mainly due to a decrease in professional services expenses[15] - R&D expenses decreased to $13.8 million in Q3 2025 from $16.0 million in Q3 2024, primarily due to reduced external expenses related to KRRO-110[14] - Research and development expenses for the nine months ended September 30, 2025, increased to $54.59 million, up 17% from $46.67 million in the same period of 2024[24] Assets and Equity - Cash, cash equivalents, and marketable securities as of September 30, 2025, totaled $102.49 million, down from $163.05 million as of December 31, 2024[26] - Total assets decreased to $161.55 million as of September 30, 2025, from $226.24 million as of December 31, 2024[26] - Total stockholders' equity as of September 30, 2025, was $99.03 million, down from $160.42 million as of December 31, 2024[26] Clinical Development - KRRO-110 produced functional M-AAT protein in AATD patients, but did not reach the projected protein levels based on preclinical data[5] - The company plans to nominate a development candidate for a GalNAc-conjugated construct for AATD in the first half of 2026[5] - Korro has nominated KRRO-121 for hyperammonemia treatment, with regulatory filing anticipated in the second half of 2026[10] - The REWRITE clinical trial has completed all six planned single ascending dose cohorts in healthy volunteers, with no dose-limiting toxicities observed[6] Strategic Changes - A strategic restructuring will reduce the workforce by approximately 34%, with one-time restructuring charges estimated at $2.4 million[10]

Core Insights - Korro Bio, Inc. has provided updates on its Phase 1/2a REWRITE clinical trial for KRRO-110, reported third-quarter financial results, and outlined strategic business decisions [1][5]. Clinical Trial Update - KRRO-110 successfully generated functional M-AAT protein in patients with Alpha-1 Antitrypsin Deficiency (AATD), although the protein levels were below preclinical projections [2][5]. - The REWRITE trial has completed all six planned single ascending dose cohorts in healthy volunteers, with no dose-limiting toxicities observed [4][7]. - The trial is currently evaluating KRRO-110 in two AATD patient cohorts at doses of 0.6 mg/kg and 0.8 mg/kg [4][7]. Development Candidates - Korro has nominated KRRO-121, a GalNAc-conjugated construct aimed at treating hyperammonemia, marking an expansion of its RNA editing platform [3][5]. - The company plans to advance KRRO-121 and a GalNAc version for AATD patients into clinical trials in the second half of 2026 and 2027, respectively [3][5]. Financial Results - As of September 30, 2025, Korro reported cash, cash equivalents, and marketable securities totaling $102.5 million, down from $163.1 million at the end of 2024 [12][26]. - Collaboration revenue for the third quarter of 2025 was $1.1 million, compared to no revenue in the same period of 2024 [13]. - Research and development expenses decreased to $13.8 million from $16.0 million year-over-year, while general and administrative expenses also saw a decline [14][15]. Strategic Restructuring - The company is implementing a strategic restructuring that will reduce its workforce by approximately one-third to focus on generating clinical data and advancing GalNAc-conjugated programs [3][18]. - This restructuring is expected to extend Korro's cash runway into the second half of 2027, with one-time restructuring charges estimated at $2.4 million [18]. Regulatory Milestones - KRRO-110 has received Investigational New Drug clearance from the FDA, along with Fast Track and Orphan Drug Designations [7][19]. - The company is prioritizing high-potential GalNAc-conjugated programs targeting the liver, including KRRO-121 [7][8].

Core Insights - Korro Bio, Inc. is actively participating in several investor and scientific conferences throughout September 2025, showcasing its commitment to engaging with the investment community and sharing insights on its innovative approaches in genetic medicine [1][2][3][4][5][6]. Company Overview - Korro Bio is a clinical-stage biopharmaceutical company focused on developing a new class of genetic medicines that utilize RNA editing to address both rare and prevalent diseases. The company aims to harness the body's natural RNA editing process for precise and transient single base edits, which may enhance specificity and long-term tolerability compared to traditional DNA editing methods [7]. Upcoming Events - Key management members, including Dr. Ram Aiyar (CEO), Dr. Loic Vincent (CSO), and Vineet Agarwal (CFO), will participate in various investor meetings and presentations at notable conferences such as: - Citi's 2025 Biopharma Back to School Conference on September 3, 2025 [1] - Cantor Global Healthcare Conference on September 4, 2025 [2] - Wells Fargo Securities Healthcare Conference on September 5, 2025 [3] - H.C. Wainwright 27th Annual Global Investment Conference and Morgan Stanley 23rd Annual Global Healthcare Conference on September 8, 2025 [4][5] - RNA Leaders USA Congress on September 11, 2025, where Mr. Todd Chappell will present on RNA editing therapies [6]. Communication Strategy - The company plans to utilize its Investor Relations website, LinkedIn, and X (Twitter) for disclosing material nonpublic information and fulfilling its disclosure obligations under Regulation FD. Investors are encouraged to monitor these platforms for updates [8].

[PART I. FINANCIAL INFORMATION](index=7&type=section&id=PART%20I.%20FINANCIAL%20INFORMATION) [Financial Statements (Unaudited)](index=7&type=section&id=Item%201.%20Financial%20Statements%20(Unaudited)) This section presents the unaudited condensed consolidated financial statements for the periods ended June 30, 2025, including balance sheets, statements of operations, stockholders' equity, and cash flows, with accompanying notes [Condensed Consolidated Balance Sheets](index=7&type=section&id=Condensed%20Consolidated%20Balance%20Sheets) Total assets decreased to **$180.4 million** by June 30, 2025, from **$226.2 million** at year-end 2024, driven by reduced cash and securities, while the accumulated deficit grew to **$315.7 million** Condensed Consolidated Balance Sheet Highlights (in thousands) | Metric | June 30, 2025 | December 31, 2024 | | :--- | :--- | :--- | | **Assets** | | | | Cash and cash equivalents | $33,612 | $55,643 | | Total current assets | $102,634 | $131,532 | | Total assets | $180,425 | $226,240 | | **Liabilities & Stockholders' Equity** | | | | Total liabilities | $65,322 | $65,825 | | Accumulated deficit | $(315,743) | $(266,586) | | Total stockholders' equity | $115,103 | $160,415 | [Condensed Consolidated Statements of Operations and Comprehensive Loss](index=8&type=section&id=Condensed%20Consolidated%20Statements%20of%20Operations%20and%20Comprehensive%20Loss) Collaboration revenue reached **$4.0 million** for the six months ended June 30, 2025, but increased research and development expenses led to a higher net loss of **$49.2 million** Statement of Operations Summary (Six Months Ended June 30, in thousands) | Metric | 2025 | 2024 | | :--- | :--- | :--- | | Collaboration revenue | $4,010 | $— | | Research and development | $40,770 | $30,710 | | General and administrative | $15,462 | $14,868 | | Loss from operations | $(52,222) | $(45,578) | | Net loss | $(49,157) | $(41,383) | | Net loss per share | $(5.24) | $(4.87) | [Condensed Consolidated Statements of Stockholders' Equity](index=9&type=section&id=Condensed%20Consolidated%20Statements%20of%20Stockholders'%20Equity) Total stockholders' equity decreased from **$160.4 million** at December 31, 2024, to **$115.1 million** at June 30, 2025, primarily due to the period's net loss - Total stockholders' equity decreased from **$160.4 million** at December 31, 2024, to **$115.1 million** at June 30, 2025, mainly due to the net loss incurred during the period[23](index=23&type=chunk) [Condensed Consolidated Statements of Cash Flows](index=10&type=section&id=Condensed%20Consolidated%20Statements%20of%20Cash%20Flows) Net cash used in operating activities was **$43.7 million** for H1 2025, while investing activities provided **$21.5 million**, a significant shift from the **$108.0 million** used in H1 2024 Cash Flow Summary (Six Months Ended June 30, in thousands) | Activity | 2025 | 2024 | | :--- | :--- | :--- | | Net cash used in operating activities | $(43,680) | $(36,484) | | Net cash provided by (used in) investing activities | $21,481 | $(108,004) | | Net cash provided by financing activities | $177 | $67,695 | [Notes to Unaudited Condensed Consolidated Financial Statements](index=11&type=section&id=Notes%20to%20Unaudited%20Condensed%20Consolidated%20Financial%20Statements) Notes confirm **$119.6 million** in cash and securities is sufficient for 12 months, detail **$4.0 million** in Novo Nordisk collaboration revenue, and disclose a May 2025 restructuring with a **19% workforce reduction** - The company believes its existing cash, cash equivalents, and marketable securities of **$119.6 million** as of June 30, 2025, are sufficient to fund planned operations for at least 12 months from the issuance date of the financial statements[31](index=31&type=chunk) - Under the collaboration agreement with Novo Nordisk, the company recognized **$4.0 million** in revenue for the six months ended June 30, 2025, with the total transaction price for the first program target estimated at **$39.9 million**[68](index=68&type=chunk) - On May 7, 2025, the company initiated a strategic plan that included a **19% workforce reduction** (21 positions), resulting in a one-time severance charge of **$1.2 million** during the second quarter[86](index=86&type=chunk) [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=24&type=section&id=Item%202.%20Management's%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management discusses the company's clinical-stage focus on RNA editing, with lead candidate KRRO-110 in Phase 1/2a trials, and highlights a **$10.1 million** increase in H1 2025 R&D expenses, confirming a cash runway into 2027 - The company's lead candidate, KRRO-110 for Alpha-1 Antitrypsin Deficiency (AATD), is in a Phase 1/2a clinical trial (REWRITE), with interim data from single ascending doses expected in the second half of 2025[92](index=92&type=chunk) Research and Development Expenses (Six Months Ended June 30, in thousands) | Expense Category | 2025 | 2024 | Change | | :--- | :--- | :--- | :--- | | KRRO-110 (AATD) external expenses | $12,557 | $9,222 | $3,335 | | Other research & pre-development | $9,695 | $6,272 | $3,423 | | Personnel expenses | $13,018 | $9,551 | $3,467 | | **Total R&D Expenses** | **$40,770** | **$30,710** | **$10,060** | - As of June 30, 2025, the company had **$119.6 million** in cash, cash equivalents, and marketable securities, which is expected to be sufficient to fund operating expenses and capital expenditure requirements into 2027[122](index=122&type=chunk) - Net cash used in operating activities increased to **$43.7 million** for the six months ended June 30, 2025, from **$36.5 million** in the prior-year period, primarily due to a higher net loss and changes in operating assets and liabilities[129](index=129&type=chunk)[130](index=130&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=38&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) The company's primary market risk is interest rate sensitivity on its **$119.6 million** cash and securities portfolio, which management deems immaterial, with foreign currency risk also considered minimal - The company's main market risk is interest rate sensitivity on its portfolio of cash, cash equivalents, and marketable securities, valued at **$119.6 million** as of June 30, 2025[139](index=139&type=chunk) - Management believes that an immediate **10% change** in market interest rates would not have a material effect on the fair market value of its cash and investments[139](index=139&type=chunk) - Exposure to foreign currency risk is considered minimal as operations are primarily in the U.S. and contracts in foreign currencies are of short duration[140](index=140&type=chunk) [Controls and Procedures](index=38&type=section&id=Item%204.%20Controls%20and%20Procedures) Management, including the CEO and CFO, confirmed the effectiveness of disclosure controls and procedures as of June 30, 2025, with no material changes to internal control over financial reporting during the quarter - Management, with the participation of the CEO and CFO, evaluated the company's disclosure controls and procedures and concluded they were effective at the reasonable assurance level as of June 30, 2025[142](index=142&type=chunk) - No changes in internal control over financial reporting occurred during the most recently completed fiscal quarter that have materially affected, or are reasonably likely to materially affect, these controls[143](index=143&type=chunk) [PART II. OTHER INFORMATION](index=39&type=section&id=PART%20II.%20OTHER%20INFORMATION) [Legal Proceedings](index=39&type=section&id=Item%201.%20Legal%20Proceedings) The company is not currently involved in any material legal proceedings expected to have a material adverse effect on its business - As of the report date, the company is not party to any claim or litigation that is expected to have a material adverse effect on its business[145](index=145&type=chunk) [Risk Factors](index=39&type=section&id=Item%201A.%20Risk%20Factors) Key risks include a history of significant losses, the unproven nature of its novel RNA editing technology, early-stage clinical development, and substantial risks related to regulatory approval, manufacturing, competition, and intellectual property - The company has a history of significant operating losses, with an accumulated deficit of **$315.7 million** as of June 30, 2025, and expects to incur losses for the foreseeable future[147](index=147&type=chunk) - RNA editing is a novel technology with limited clinical validation, and the company's approaches are unproven and may never lead to marketable products[174](index=174&type=chunk) - The company has only dosed a few participants in its first clinical trial for KRRO-110 and has not completed any clinical trials, with favorable preclinical results not predictive of clinical trial outcomes[156](index=156&type=chunk) - The company faces risks related to obtaining and protecting its intellectual property, including the possibility that patents may not be granted, may be challenged, or may not provide sufficient protection against competitors[300](index=300&type=chunk)[303](index=303&type=chunk) [Unregistered Sales of Equity Securities and Use of Proceeds](index=127&type=section&id=Item%202.%20Unregistered%20Sales%20of%20Equity%20Securities%20and%20Use%20of%20Proceeds) This item is not applicable for the reporting period - Not applicable[404](index=404&type=chunk) [Defaults Upon Senior Securities](index=127&type=section&id=Item%203.%20Defaults%20Upon%20Senior%20Securities) This item is not applicable for the reporting period - Not applicable[405](index=405&type=chunk) [Mine Safety Disclosures](index=127&type=section&id=Item%204.%20Mine%20Safety%20Disclosures) This item is not applicable for the reporting period - Not applicable[406](index=406&type=chunk) [Other Information](index=127&type=section&id=Item%205.%20Other%20Information) Several executive officers adopted Rule 10b5-1 trading plans during Q2 2025 for the potential sale of shares issuable upon stock option exercise - During the three months ended June 30, 2025, CEO Ram Aiyar, COO Todd Chappell, CSO Loïc Vincent, and General Counsel Jeffrey Cerio each adopted a Rule 10b5-1 plan for the potential sale of common stock issuable upon the exercise of stock options[407](index=407&type=chunk) [Exhibits](index=128&type=section&id=Item%206.%20Exhibits) This section lists all exhibits filed with the Form 10-Q, including corporate governance documents and officer certifications required by the Sarbanes-Oxley Act - The report includes a list of filed exhibits, such as corporate governance documents and officer certifications required under the Sarbanes-Oxley Act[409](index=409&type=chunk)

[Business Overview and Highlights](index=1&type=section&id=Business%20Overview%20and%20Highlights) Korro reported significant progress in its Phase 1/2a REWRITE clinical trial for KRRO-110, achieving EMA Orphan Drug Designation and ending Q2 2025 with a strong cash position, with key milestones anticipated in H2 2025 [Second Quarter 2025 Highlights](index=1&type=section&id=Second%20Quarter%202025%20Highlights) Korro reported significant progress in its Phase 1/2a REWRITE clinical trial for KRRO-110, having dosed over 80% of healthy volunteers with no serious adverse events. The company received EMA Orphan Drug Designation for KRRO-110 and ended the second quarter of 2025 with a strong cash position of $119.6 million. Key milestones, including interim trial data and a new development candidate announcement, are expected in the second half of 2025 - The Phase 1/2a REWRITE clinical trial for KRRO-110 is progressing well, with an interim data readout expected in the second half of 2025[4](index=4&type=chunk)[6](index=6&type=chunk) - Dosing has been completed for over **80%** of planned healthy volunteers in the single ascending dose (SAD) cohorts, with no treatment-emergent serious adverse events (SAEs) or dose-limiting toxicities observed[6](index=6&type=chunk)[7](index=7&type=chunk) - The European Medicines Agency (EMA) granted Orphan Drug Designation to KRRO-110 for the treatment of Alpha-1 Antitrypsin Deficiency (AATD)[6](index=6&type=chunk)[7](index=7&type=chunk) - The company plans to announce its rare metabolic disorder development candidate by the end of 2025[4](index=4&type=chunk)[6](index=6&type=chunk) - Ended the second quarter of 2025 with **$119.6 million** in cash, cash equivalents, and marketable securities[6](index=6&type=chunk) [Pipeline and Strategic Updates](index=1&type=section&id=Pipeline%20and%20Strategic%20Updates) Korro's KRRO-110 program is advancing with positive clinical trial results and regulatory designations, while the company progresses towards key milestones including new development candidates and strategic collaborations through 2027 [KRRO-110 Program Update](index=1&type=section&id=KRRO-110%20Program%20Update) The Phase 1/2a REWRITE clinical trial for KRRO-110 in AATD is advancing well, with over 80% of healthy volunteers dosed across multiple single ascending dose (SAD) cohorts, showing a safe and well-tolerated profile. The drug also received Orphan Drug Designation from the European Medicines Agency (EMA), adding to its previous U.S. FDA designation, which provides significant development incentives - More than **80%** of planned healthy volunteers have received KRRO-110 across multiple SAD cohorts, including dose levels expected to be pharmacologically relevant[7](index=7&type=chunk) - As of August 12, 2025, KRRO-110 continues to be safe and well-tolerated, with no treatment-emergent SAEs or dose-limiting toxicities observed[7](index=7&type=chunk) - The EMA granted orphan designation status to KRRO-110, which provides development incentives such as protocol assistance, reduced regulatory fees, and market exclusivity upon approval[7](index=7&type=chunk)[8](index=8&type=chunk) - KRRO-110 also received orphan drug designation from the U.S. Food and Drug Administration in March 2025[8](index=8&type=chunk) [Anticipated Upcoming Milestones](index=2&type=section&id=Anticipated%20Upcoming%20Milestones) Korro anticipates several key milestones through 2027, guided by its 3-2-1 strategy. Near-term events include an interim data readout from the KRRO-110 trial in H2 2025, the announcement of a new rare metabolic disorder candidate by year-end 2025, and the full completion of the REWRITE trial in 2026. The company is also progressing its central nervous system programs and its collaboration with Novo Nordisk - Interim data from the Part 1 SAD portion of the Phase 1/2a REWRITE clinical trial is expected in the second half of 2025[14](index=14&type=chunk) - Completion of the full REWRITE trial, including the Part 2 multiple ascending dose (MAD) portion, is expected in 2026[14](index=14&type=chunk) - A development candidate for its rare metabolic disorder program will be announced by the end of 2025[14](index=14&type=chunk) - The company continues to execute its **3-2-1 strategy**, aiming for three clinical-stage programs and targeting two tissue types by the end of 2027[14](index=14&type=chunk) - Progress continues on the collaboration with Novo Nordisk to advance up to two preclinical programs for cardiometabolic diseases[14](index=14&type=chunk) [Financial Performance](index=2&type=section&id=Financial%20Performance) Korro's second quarter 2025 financial results show increased collaboration revenue and operating expenses, resulting in a net loss, while maintaining a strong cash position expected to fund operations into 2027 [Second Quarter 2025 Financial Results](index=2&type=section&id=Second%20Quarter%202025%20Financial%20Results) For the second quarter of 2025, Korro reported **$1.5 million** in collaboration revenue, a new stream compared to the prior year. Operating expenses increased to **$28.7 million**, driven primarily by higher R&D costs, resulting in a net loss of **$25.8 million**. The company maintained a solid financial position, ending the quarter with **$119.6 million** in cash and equivalents, which is expected to fund operations into 2027 Financial Metric Summary | Financial Metric | Q2 2025 | Q2 2024 | Change | | :--- | :--- | :--- | :--- | | Cash & Marketable Securities | $119.6M (as of Jun 30) | $163.1M (as of Dec 31, 2024) | -$43.5M | | Collaboration Revenue | $1.5M | $0.0M | +$1.5M | | R&D Expenses | $21.0M | $17.1M | +$3.9M | | G&A Expenses | $7.6M | $7.0M | +$0.6M | | Net Loss | $25.8M | $21.8M | +$4.0M | - Cash, cash equivalents, and marketable securities of **$119.6 million** as of June 30, 2025, are expected to fund operating expenses and capital expenditure requirements into 2027[10](index=10&type=chunk) - The increase in collaboration revenue was due to revenue earned from the collaboration with Novo Nordisk[11](index=11&type=chunk) - The rise in R&D expenses was primarily driven by increases in personnel expenses and other research and pre-development candidate costs[12](index=12&type=chunk) [Condensed Consolidated Statements of Operations](index=5&type=section&id=Condensed%20Consolidated%20Statements%20of%20Operations) This section provides the unaudited condensed consolidated statements of operations for the three and six months ended June 30, 2025, and June 30, 2024. It details revenue, operating expenses, other income, net loss, and comprehensive loss for these periods Condensed Consolidated Statements of Operations (in thousands) | (in thousands) | Three Months Ended June 30, 2025 | Three Months Ended June 30, 2024 | Six Months Ended June 30, 2025 | Six Months Ended June 30, 2024 | | :--- | :--- | :--- | :--- | :--- | | **Collaboration revenue** | **$1,460** | **$—** | **$4,010** | **$—** | | Research and development | $21,031 | $17,138 | $40,770 | $30,710 | | General and administrative | $7,631 | $6,987 | $15,462 | $14,868 | | **Total operating expenses** | **$28,662** | **$24,125** | **$56,232** | **$45,578** | | **Loss from operations** | **($27,202)** | **($24,125)** | **($52,222)** | **($45,578)** | | Other income, net | $1,433 | $2,329 | $3,066 | $4,242 | | **Net loss** | **($25,770)** | **($21,826)** | **($49,157)** | **($41,383)** | | **Net loss per share** | **($2.74)** | **($2.43)** | **($5.24)** | **($4.87)** | [Selected Condensed Consolidated Balance Sheet Data](index=6&type=section&id=Selected%20Condensed%20Consolidated%20Balance%20Sheet%20Data) This section presents selected unaudited condensed consolidated balance sheet data as of June 30, 2025, compared to December 31, 2024. It highlights key figures including cash, total assets, total liabilities, and total stockholders' equity Selected Condensed Consolidated Balance Sheet Data (in thousands) | (in thousands) | June 30, 2025 | December 31, 2024 | | :--- | :--- | :--- | | Cash, cash equivalents and marketable securities | $119,626 | $163,054 | | Working capital | $85,461 | $116,572 | | Total assets | $180,425 | $226,240 | | Total liabilities | $65,322 | $65,825 | | Total stockholders' equity | $115,103 | $160,415 | [Company and Program Information](index=3&type=section&id=Company%20and%20Program%20Information) This section details the REWRITE clinical trial design, the genetic basis of AATD, KRRO-110's mechanism of action, and Korro Bio's proprietary RNA editing platform for genetic medicines [About REWRITE Clinical Trial](index=3&type=section&id=About%20REWRITE%20Clinical%20Trial) The REWRITE trial is a two-part, single and multiple dose-escalating study designed to evaluate the safety and tolerability of KRRO-110 in up to 64 participants, including both healthy adults and AATD patients. The trial will also assess pharmacokinetic and pharmacodynamic parameters to guide future dose selection, with interim data from Part 1 expected in the second half of 2025 and full study completion anticipated in 2026 - REWRITE is a two-part study (Part 1: single ascending doses; Part 2: multiple ascending doses) that will enroll up to **64 participants**, including healthy volunteers and AATD patients with the PiZZ genotype[16](index=16&type=chunk) - The primary endpoints are safety and tolerability, while secondary endpoints include pharmacokinetic and pharmacodynamic parameters to guide optimal dose selection[16](index=16&type=chunk) - Interim data from Part 1 is expected in the second half of 2025, and the study is anticipated to be completed in 2026[16](index=16&type=chunk) [About Alpha-1 Antitrypsin Deficiency (AATD) and KRRO-110](index=3&type=section&id=About%20Alpha-1%20Antitrypsin%20Deficiency%20(AATD)%20and%20KRRO-110) Alpha-1 Antitrypsin Deficiency (AATD) is a genetic disorder caused by a mutation in the SERPINA1 gene, leading to severe lung and liver disease. Korro's lead candidate, KRRO-110, utilizes its proprietary OPERA® RNA editing platform to co-opt an endogenous enzyme (ADAR) to repair the mutated RNA. This process is designed to restore the secretion of normal AAT protein, potentially clearing harmful protein aggregates from the liver and protecting lung function - AATD is a genetic disorder most commonly caused by a single G-to-A missense mutation in the SERPINA1 gene, leading to pulmonary emphysema and/or hepatic cirrhosis[17](index=17&type=chunk) - KRRO-110 is an RNA editing oligonucleotide from the OPERA® platform designed to use the endogenous ADAR enzyme to edit the mutated SERPINA1 RNA[17](index=17&type=chunk) - The therapeutic goal is to repair an amino acid codon, restore normal AAT protein secretion, clear protein aggregates from the liver, and preserve lung function[17](index=17&type=chunk) [About Korro Bio](index=3&type=section&id=About%20Korro%20Bio) Korro Bio is a clinical-stage biopharmaceutical company focused on developing a new class of genetic medicines based on RNA editing for both rare and prevalent diseases. The company's proprietary OPERA® platform is designed to harness the body's natural RNA editing process to make precise, transient single-base edits. This approach aims to offer improved specificity and long-term tolerability compared to DNA-based genetic medicines - Korro is a clinical-stage biopharmaceutical company developing genetic medicines based on editing RNA[18](index=18&type=chunk) - The company's platform is designed to enable precise yet transient single base edits by harnessing the body's natural RNA editing process[18](index=18&type=chunk) - By editing RNA instead of DNA, Korro aims to expand the reach of genetic medicines with increased specificity and improved long-term tolerability[18](index=18&type=chunk) [Legal Disclosures](index=3&type=section&id=Legal%20Disclosures) This section provides cautionary language regarding forward-looking statements, highlighting inherent risks and uncertainties in future projections and directing readers to SEC filings for comprehensive risk factors [Forward-Looking Statements](index=3&type=section&id=Forward-Looking%20Statements) This section contains standard cautionary language regarding forward-looking statements within the press release. It advises investors that statements about future events, such as clinical trial timelines, data readouts, candidate announcements, and financial runway, are subject to significant risks and uncertainties and should not be unduly relied upon. Readers are directed to Korro's SEC filings for a more comprehensive discussion of potential risks - The press release includes forward-looking statements concerning the timing of clinical trial data, announcement of development candidates, KRRO-110's potential, and the company's cash runway[21](index=21&type=chunk) - Actual results may differ materially from current expectations due to various factors, including risks inherent in clinical trials, regulatory oversight, and general economic conditions[21](index=21&type=chunk) - Korro does not undertake any duty to publicly update or revise forward-looking statements and advises investors to consult its SEC filings for a full list of risk factors[21](index=21&type=chunk)

Core Insights - Korro Bio, Inc. is progressing well in its Phase 1/2a REWRITE clinical trial for KRRO-110, with an interim readout expected in the second half of 2025, indicating potential best-in-class status for the treatment of Alpha-1 Antitrypsin Deficiency (AATD) [1][2][4] - The European Medicines Agency (EMA) has granted Orphan Drug Designation to KRRO-110, which provides various development incentives [1][5] - The company ended Q2 2025 with $119.6 million in cash, cash equivalents, and marketable securities, which is expected to fund operations into 2027 [6][19] Clinical Development Updates - Over 80% of planned healthy volunteers have been dosed in the REWRITE trial, with no serious adverse events or dose-limiting toxicities reported [1][5] - The REWRITE trial consists of two parts: Part 1 (single ascending doses) and Part 2 (multiple ascending doses), with completion of the trial anticipated in 2026 [4][10] - The interim data from Part 1 is expected to provide insights into the pharmacologically relevant dose levels for PiZZ patients [5][10] Financial Performance - Collaboration revenue for Q2 2025 was $1.5 million, a significant increase from no collaboration revenue in Q2 2024, attributed to the partnership with Novo Nordisk [7] - Research and Development (R&D) expenses rose to $21.0 million in Q2 2025 from $17.1 million in Q2 2024, driven by increased personnel and research costs [8] - General and Administrative (G&A) expenses increased to $7.6 million in Q2 2025 from $7.0 million in Q2 2024, primarily due to higher personnel-related expenses [9] Strategic Initiatives - The company is executing its 3-2-1 strategy, aiming to establish three clinical-stage development programs targeting two tissue types by leveraging its OPERA® platform [2][5] - A development candidate for a rare metabolic disorder program is expected to be announced by the end of 2025, which will be administered subcutaneously [1][13] - Korro continues to advance its collaboration with Novo Nordisk, focusing on cardiometabolic diseases with high unmet clinical needs [5][13]