Dyne Therapeutics, Inc.

Previous wording

We are developing zeleciment rostudirsen, or z-rostudirsen (also known as DYNE-251), for the treatment of DMD amenable to exon 51 skipping. Z-rostudirsen is designed to enable the production of near full-length dystrophin in muscle and the CNS to provide functional improvement. Z-rostudirsen has received Breakthrough Therapy, Fast Track and Rare Pediatric Disease designations from the U.S. Food and Drug Administration, or FDA, as well as Orphan Drug designation from the FDA, the European Medicines Agency and the Japanese Ministry of Health, Labour and Welfare for the treatment of individuals with DMD, amenable to exon 51 skipping. Additionally, we are advancing four development candidates (DYNE-253, DYNE-245, DYNE-244 and DYNE-255) for the treatment of DMD amenable to skipping of exons 53, 45, 44, 55, respectively, into IND-enabling studies.

Current wording

We are developing zeleciment rostudirsen, or z-rostudirsen (also known as DYNE-251), for the treatment of DMD amenable to exon 51 skipping. Z-rostudirsen is designed to enable the production of near full-length dystrophin in muscle and the CNS to provide functional improvement. Z-rostudirsen has received Breakthrough Therapy, Fast Track and Rare Pediatric Disease designations from the U.S. Food and Drug Administration, or FDA, as well as Orphan Drug designation from the FDA, the European Medicines Agency and the Japanese Ministry of Health, Labour and Welfare for the treatment of individuals with DMD, amenable to exon 51 skipping. Additionally, we are advancing four development candidates (DYNE-244, DYNE-245, DYNE-253 and DYNE-255) for the treatment of DMD amenable to skipping of exons 44, 45, 53 and 55, respectively, into IND-enabling studies. In September 2026, we presented preclinical data supporting these programs, includingin vitro exon-skipping results for each of the four candidates andin vivo pharmacokinetic and pharmacodynamic results for DYNE-253.

Previous wording

Z-rostudirsen is being evaluated in the long-term extension portion of the DELIVER trial, a global Phase 1/2 clinical trial designed to be registrational, and the FORZETTO trial, a global Phase 3 clinical trial designed to be confirmatory. We have aligned with the FDA on the FORZETTO trial design and protocol. The registrational expansion cohort of the global Phase 1/2 DELIVER clinical trial of z-rostudirsen met its primary endpoint. Data from the DELIVER trial served as the basis for a biologics license application, or BLA, for potential U.S. Accelerated Approval.

Current wording

Z-rostudirsen is currently being evaluated in the long-term extension portion of the DELIVER trial, a global Phase 1/2 clinical trial designed to be registrational, and the FORZETTO trial, a global Phase 3 clinical trial designed to be confirmatory. We have aligned with the FDA on the FORZETTO trial design and protocol. The registrational expansion cohort, or REC, of the global Phase 1/2 DELIVER clinical trial of z-rostudirsen met its primary endpoint. Data from the DELIVER trial served as the basis for the biologics license application, or BLA, that we submitted for U.S. Accelerated Approval in May 2026.

Previous wording

In May 2026, we initiated our Phase 3 FORZETTO clinical trial, a global, randomized, placebo-controlled, double-blind, confirmatory Phase 3 trial designed to assess the efficacy, safety, and tolerability of z-rostudirsen administered intravenously to ambulatory male participants with DMD amenable to exon 51 skipping. The trial will enroll approximately 90 participants 4 to 18 years of age who will be randomized 1:1 to receive 20 mg/kg of z-rostudirsen or placebo every four weeks (Q4W). The primary endpoint is the change from baseline in rise from floor (RFF) velocity at Week 73. Secondary endpoints include changes from baseline in stride velocity 95th centile (SV95C), North Star Ambulatory Assessment (NSAA) total score, 10-meter walk/run (10MWR) velocity, four-stair climb (4SC) velocity and forced vital capacity percent predicted (FVC%p), as well as additional functional and patient-reported outcome measures. Following the 72-week double-blind placebo-controlled treatment period, participants will be eligible to enroll in a 96-week open-label long-term extension. We have aligned with the FDA on the FORZETTO Phase 3 trial design and protocol. FORZETTO is intended to serve as a confirmatory trial to support the potential conversion of Accelerated Approval to traditional approval in the United States and to support ex-U.S. marketing applications.

Current wording

In May 2026, we initiated our Phase 3 FORZETTO clinical trial, a global, randomized, placebo-controlled, double-blind, confirmatory Phase 3 trial designed to assess the efficacy, safety, and tolerability of z-rostudirsen administered intravenously to ambulatory male participants with DMD amenable to exon 51 skipping. The trial will enroll approximately 90 participants 4 to 18 years of age who will be randomized 1:1 to receive 20 mg/kg (approximate phosphorodiamidate morpholino oligomer, or PMO dose) of z-rostudirsen or placebo every four weeks (Q4W). The primary endpoint is the change from baseline in rise from floor (RFF) velocity at Week 73. Secondary endpoints include changes from baseline in stride velocity 95th centile (SV95C), North Star Ambulatory Assessment (NSAA) total score, 10-meter walk/run (10MWR) velocity, four-stair climb (4SC) velocity and forced vital capacity percent predicted (FVC%p), as well as additional functional and patient-reported outcome measures. Following the 72-week double-blind placebo-controlled treatment period, participants will be eligible to enroll in a 96-week open-label long-term extension. We have aligned with the FDA on the FORZETTO Phase 3 trial design and protocol. FORZETTO is intended to support conversion of Accelerated Approval, if granted, to traditional approval in the U.S. and to support marketing applications outside the United States.

Previous wording

In July 2026, we announced that the FDA accepted for review our BLA for z-rostudirsen for the treatment of individuals with DMD amenable to exon 51 skipping. The FDA has granted the BLA priority review and assigned a Prescription Drug User Fee Act, or PDUFA, target action date of January 21, 2027. We continue to expect a potential U.S. launch of z-rostudirsen in the first quarter of 2027, assuming FDA approval is received on the anticipated timeline. We continue to pursue approval pathways outside of the United States for z-rostudirsen.

Current wording

In July 2026, we announced that the FDA accepted for review our BLA for z-rostudirsen for the treatment of individuals with DMD amenable to exon 51 skipping. The FDA has granted the BLA priority review and assigned a Prescription Drug User Fee Act, or PDUFA, target action date of January 21, 2027. We continue to expect a potential U.S. launch of z-rostudirsen in the first quarter of 2027, assuming FDA approval is received on the anticipated timeline.

Previous wording

Z-basivarsen is being evaluated in the ACHIEVE trial, a global Phase 1/2 clinical trial designed to be registrational, and the HARMONIA trial, a global Phase 3 clinical trial designed to be confirmatory. We have aligned with the FDA on the HARMONIA trial design and protocol.

Current wording

Z-basivarsen is currently being evaluated in the long-term extension portion and the REC of the ACHIEVE trial, a global Phase 1/2 clinical trial designed to be registrational, and the HARMONIA trial, a global Phase 3 clinical trial designed to be confirmatory. We have aligned with the FDA on the HARMONIA trial design and protocol.

Previous wording

In March 2026, we initiated our Phase 3 HARMONIA clinical trial, a global, randomized, placebo controlled, double-blind, confirmatory Phase 3 trial designed to assess the multi-system efficacy, safety, and tolerability of z-basivarsen administered intravenously to individuals with DM1. We began dosing patients in July 2026. The trial will enroll approximately 150 participants age 16 and older who will be randomized 1:1 to receive 6.8 mg/kg of z-basivarsen or placebo every eight weeks (Q8W). The primary endpoint is the change from baseline in the five times sit to stand (5xSTS) test at week 49. Secondary endpoints include video hand opening time, quantitative muscle testing, the 10-Meter Walk/Run test, the Myotonic Dystrophy Health Index, and additional patient- and clinician-reported outcomes. The trial also includes a broad set of exploratory endpoints designed to assess multiple domains of DM1 CNS impact. Following the 48-week double-blind placebo-controlled treatment period, patients will be eligible to enroll in a 24-week long-term extension.

Current wording

In March 2026, we initiated our Phase 3 HARMONIA clinical trial, a global, randomized, placebo controlled, double-blind, confirmatory Phase 3 trial designed to assess the multi-system efficacy, safety, and tolerability of z-basivarsen administered intravenously to individuals with DM1. We began dosing patients in July 2026. The trial will enroll approximately 150 participants age 16 and older who will be randomized 1:1 to receive 6.8 mg/kg (approximate antisense oligonucleitide, or ASO, dose) of z-basivarsen or placebo every eight weeks (Q8W). The primary endpoint is the change from baseline in the five times sit to stand (5xSTS) test at week 49. Secondary endpoints include video hand opening time (vHOT), quantitative muscle testing, the 10-Meter Walk/Run test, the Myotonic Dystrophy Health Index, and additional patient- and clinician-reported outcomes. The trial also includes a broad set of exploratory endpoints designed to assess multiple domains of DM1 CNS impact. Following the 48-week double-blind placebo-controlled treatment period, patients will be eligible to enroll in a 24-week long-term extension. HARMONIA is intended to support conversion of Accelerated Approval, if granted, to traditional approval in the U.S. and to support marketing applications outside the United States.

Previous wording

In June 2026, we completed enrollment of 71 participants in the registrational expansion cohort, or REC, of the ACHIEVE trial. We plan to announce data from the REC in the first quarter of 2027 to support a potential BLA submission to the FDA for U.S. Accelerated Approval in the third quarter of 2027. We anticipate a potential U.S. launch of z-basivarsen in the first half of 2028, assuming we receive favorable data from the REC, priority review is granted, and FDA approval is received on the anticipated timeline. We continue to pursue approval pathways outside of the United States for z-basivarsen.

Current wording

Separately, the REC of the ACHIEVE trial completed enrollment in June 2026. The primary endpoint is the change from baseline in vHOT at six months. Participants in the REC had a mean baseline value for vHOT of 8.3 seconds (standard deviation at baseline: 6.0 seconds). We plan to announce data from the REC in the first quarter of 2027 to support a potential BLA submission to the FDA for U.S. Accelerated Approval in the third quarter of 2027. We anticipate a potential U.S. launch of z-basivarsen in the first half of 2028, assuming we receive favorable data from the REC, priority review is granted, and FDA approval is received on the anticipated timeline.

Previous wording

We are developing DYNE-302 for the treatment of FSHD. DYNE-302 is designed to deliver functional improvement in individuals living with FSHD by reducing aberrant DUX4 expression. We are progressing DYNE-302 toward clinical development.

Current wording

We are developing DYNE-302 for the treatment of FSHD. DYNE-302 is designed to deliver functional improvement in individuals living with FSHD by reducing aberrant DUX4 expression. DYNE-302 leverages the same FORCE platform as our first two clinical programs, z-rostudirsen in DMD amenable to exon 51 skipping and z-basivarsen in DM1.

Previous wording

In July 2026, we announced that we received clearance from the FDA for our investigational new drug, or IND, application to initiate a Phase 1 clinical trial for DYNE-302 in FSHD. DYNE-302 leverages the same FORCE platform as our first two clinical programs, z-rostudirsen in DMD amenable to exon 51 skipping and z-basivarsen in DM1. We plan to evaluate DYNE-302 in a Phase 1 randomized, placebo-controlled, double-blind, multiple ascending dose clinical trial in ambulatory adult individuals with FSHD with a primary endpoint of safety and tolerability. The trial will also assess pharmacokinetics and pharmacodynamics, including change from baseline in muscle DUX4 transcriptome and plasma KHDC1L levels.

Current wording

In July 2026, we announced that we received clearance from the FDA for our investigational new drug, or IND, application to initiate a Phase 1 clinical trial for DYNE-302 in FSHD. We plan to evaluate DYNE-302 in a Phase 1 randomized, placebo-controlled, double-blind, MAD clinical trial in ambulatory adult individuals with FSHD with a primary endpoint of safety and tolerability. The trial will also assess pharmacokinetics and pharmacodynamics, including change from baseline in muscle DUX4 transcriptome and plasma KHDC1L levels.

Previous wording

We were incorporated and commenced operations in 2017. Since our incorporation, we have devoted substantially all of our financial resources and efforts to organizing and staffing our company, business planning, raising capital, conducting research and development activities and filing and prosecuting patent applications. We do not have any products for sale and have not generated any revenue from product sales or otherwise. To date, we have principally raised capital through sales of equity securities and our borrowing under our Loan and Security Agreement, or the Loan Agreement, with Hercules Capital, Inc., or Hercules.

Current wording

We were incorporated and commenced operations in 2017. Since our incorporation, we have devoted substantially all of our financial resources and efforts to organizing and staffing our company, business planning, raising capital, conducting research and development activities and filing and prosecuting patent applications. We do not have any products for sale and have not generated any revenue from product sales or otherwise. To date, we have principally raised capital through sales of equity securities and our borrowings under our Loan and Security Agreement, or the Loan Agreement, with Hercules Capital, Inc., or Hercules.

Previous wording

Since our inception, we have incurred significant operating losses. Our ability to generate any product revenue or product revenue sufficient to achieve profitability will depend on the successful development and eventual commercialization of one or more product candidates. For the six months ended June 30, 2026 and 2025, we reported net losses of $299.4 million and $226.2 million, respectively. As of June 30, 2026, we had an accumulated deficit of $1.7 billion.

Current wording

Since our inception, we have incurred significant operating losses. Our ability to generate any product revenue or product revenue sufficient to achieve profitability will depend on the successful development and eventual commercialization of one or more product candidates. For the nine months ended September 30, 2026 and 2025, we reported net losses of $493.0 million and $334.3 million, respectively. As of September 30, 2026, we had an accumulated deficit of $1,889 million.

Previous wording

As a result, we will need substantial additional funding to support our continuing operations and pursue our growth strategy. Until such time as we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements, and terms loans under our Loan Agreement with Hercules. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed, on favorable terms, or at all. If we fail to raise capital or enter into such agreements or arrangements as and when needed, we may have to significantly delay, reduce or eliminate the development or future commercialization of one or more product candidates we may develop.

Current wording

As a result, we will need substantial additional funding to support our continuing operations and pursue our growth strategy. Until such time as we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements, and term loans under our Loan Agreement with Hercules. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed, on favorable terms, or at all. If we fail to raise capital or enter into such agreements or arrangements as and when needed, we may have to significantly delay, reduce or eliminate the development or future commercialization of one or more product candidates we may develop.

Previous wording

We believe that our cash, cash equivalents and marketable securities as of June 30, 2026, as well as the approximately $405.0 in net proceeds from the July 2026 offering, will enable us to fund our operating expenses, debt service obligations and capital expenditure requirements into the second quarter of 2028.

Current wording

We believe that our cash, cash equivalents and marketable securities as of September 30, 2026 will enable us to fund our operating expenses, debt service obligations and capital expenditure requirements into the second quarter of 2028.

Previous wording

At this time, we cannot accurately estimate or know the nature, timing and costs of the efforts that will be necessary to complete the preclinical and clinical development of any product candidates we may develop. In particular, manufacturing costs may vary significantly from quarter to quarter. For the full year 2026, we expect manufacturing costs to increase progressively each quarter as a result of long lead times to build supply and we project manufacturing costs for z-rostudirsen, z-basivarsen and other pipeline product candidates to represent 55-65% of total research and development expenses for the full year 2026. Further, we project clinical trial costs related to z-rostudirsen, z-basivarsen and other pipeline product candidates to represent 10-20% and of total research and development expenses for the full year 2026.

Current wording

At this time, we cannot accurately estimate or know the nature, timing and costs of the efforts that will be necessary to complete the preclinical and clinical development of any product candidates we may develop. In particular, manufacturing costs may vary significantly from quarter to quarter. For the full year 2026, we expect manufacturing costs to increase progressively each quarter as a result of long lead times to build supply and we project manufacturing costs for z-rostudirsen, z-basivarsen and other pipeline product candidates to represent 55-65% of total research and development expenses for the full year 2026. Further, we project clinical trial costs related to z-rostudirsen, z-basivarsen and other pipeline product candidates to represent 10-20% of total research and development expenses for the full year 2026.

Previous wording

Interest expense consists of amortization of debt issuance costs and discount and interest expense under the Loan Agreement with Hercules.

Current wording

Interest expense consists of amortization of debt issuance costs and discount and interest expense under the Loan Agreement with Hercules and interest expense from our vendor financing arrangement.

Previous wording

Expenses related to z-rostudirsen increased in the three months ended June 30, 2026 compared to the three months ended June 30, 2025. This was attributable to increased manufacturing activity in the second quarter of 2026 of drug components primarily for clinical supply for the long-term extension of the DELIVER trial and the global confirmatory Phase 3 clinical trial of z-rostudirsen, FORZETTO, that commenced in the second quarter of 2026. Additionally, higher clinical costs were incurred in the second quarter of 2026 due to the commencement of the FORZETTO trial. Expenses related to z-basivarsen increased in the three months ended June 30, 2026 compared to the three months ended June 30, 2025. This was primarily attributable to increased manufacturing activity in the second quarter of 2026 of drug substance and components primarily for clinical supply for the registrational expansion cohort of the ACHIEVE trial and the global confirmatory Phase 3 clinical trial of z-basivarsen, HARMONIA, that commenced in the first quarter of 2026. Additionally, higher clinical costs were incurred in the second quarter of 2026 due to the completion of enrollment of the registrational expansion cohort of the ACHIEVE trial in the second quarter of 2026 and increased enrollment in the HARMONIA trial.

Current wording

Expenses related to z-rostudirsen increased in the three months ended September 30, 2026 compared to the three months ended September 30, 2025. This was attributable to increased manufacturing activity in the third quarter of 2026 of drug substance and components primarily for clinical supply for the long-term extension of the DELIVER trial and the FORZETTO trial. Additionally, higher clinical costs were incurred in the third quarter of 2026 due to increased activity in the FORZETTO trial. Expenses related to z-basivarsen decreased in the three months ended September 30, 2026 compared to the three months ended September 30, 2025. This was primarily attributable to higher manufacturing activity in the third quarter of 2025 of drug substance for clinical supply. This decrease was partially offset by higher clinical costs in the third quarter of 2026 due to the ongoing registrational expansion cohort of the ACHIEVE trial and continued enrollment in the HARMONIA trial.

Previous wording

The increase in platform and external research and development expenses in the three months ended June 30, 2026 compared to the three months ended June 30, 2025 was due to increased external research activity associated with our preclinical programs and product candidates. The increase in personnel-related expenses was primarily due to the increase of 39 employees in our research and development headcount and higher stock-based compensation expense for awards granted to new hires and existing employees. The increase in facility-related and other expenses was primarily due to the increased costs of supporting a larger number of research and development personnel.

Current wording

The increase in platform and external research and development expenses in the three months ended September 30, 2026 compared to the three months ended September 30, 2025 was due to increased external research activity associated with our preclinical programs and product candidates. The increase in personnel-related expenses was primarily due to the increase of 35 employees in our research and development headcount and higher stock-based compensation expense for awards granted to new hires and existing employees. The increase in facility-related and other expenses was primarily due to the increased costs of supporting a larger number of research and development personnel.

Previous wording

The increase in personnel-related and stock-based compensation expenses in the three months ended June 30, 2026 compared to the three months ended June 30, 2025 was due to the increase of 44 employees in our general and administrative headcount. Professional and consulting fees increased due to higher consulting costs for the preparation activities for the potential launch of z-rostudirsen and the overall growth of the organization in the three months ended June 30, 2026. Facility-related and other expenses increased due to higher costs of supporting a larger number of general and administrative personnel in the three months ended June 30, 2026.

Current wording

The increase in personnel-related and stock-based compensation expenses in the three months ended September 30, 2026 compared to the three months ended September 30, 2025 was due to the increase of 47 employees in our general and administrative headcount. Professional and consulting fees increased due to higher consulting costs for the preparation activities for the potential launch of z-rostudirsen and the overall growth of the organization in the three months ended September 30, 2026. Facility-related and other expenses increased due to higher costs of supporting a larger number of general and administrative personnel in the three months ended September 30, 2026.

Previous wording

Interest income for the three months ended June 30, 2026 and 2025 was $7.8 million and $6.6 million, respectively, due to interest earned on invested cash balances. The increase in interest income was due to increased cash, cash equivalents and marketable securities balances in the three months ended June 30, 2026 compared to the three months ended June 30, 2025.

Current wording

Interest income for the three months ended September 30, 2026 and 2025 was $9.8 million and $8.5 million, respectively, due to interest earned on invested cash balances. The increase in interest income was due to increased cash, cash equivalents and marketable securities balances in the three months ended September 30, 2026 compared to the three months ended September 30, 2025.

Previous wording

Interest expense for the three months ended June 30, 2026 was $4.6 million due to our Loan Agreement with Hercules and interest owed on our vendor financing arrangement. Interest expense for the three months ended June 30, 2025 was less than $0.1 million due to our Loan Agreement with Hercules.

Current wording

Interest expense for the three months ended September 30, 2026 was $5.9 million due to our Loan Agreement with Hercules and interest owed on our vendor financing arrangement. Interest expense for the three months ended September 30, 2025 was $2.9 million due to our Loan Agreement with Hercules.

Previous wording

Other expense, net, for the three months ended June 30, 2026 and 2025 was $0.1 million and $1.6 million, respectively, in each quarter due to realized foreign currency losses.

Current wording

Other expense, net, was $0.3 million for the three months ended September 30, 2026 due to realized foreign currency losses. Other income, net, was $0.3 million for the three months ended September 30, 2025 due to realized foreign currency gains.

Previous wording

The following table summarizes our results of operations for the six months ended June 30, 2026 and 2025:

Current wording

The following table summarizes our results of operations for the nine months ended September 30, 2026 and 2025:

Previous wording

Expenses related to z-rostudirsen increased in the six months ended June 30, 2026 compared to the six months ended June 30, 2025. This was attributable to increased manufacturing activity of drug substance and components in the six months ended June 30, 2026, primarily for clinical supply for the long-term extension of the DELIVER trial and the global confirmatory Phase 3 clinical trial of z-rostudirsen, FORZETTO, that commenced in the second quarter of 2026. Additionally, higher clinical costs were incurred in the six months ended June 30, 2026 due to the commencement of the FORZETTO trial. Expenses related to z-basivarsen decreased in the six months ended June 30, 2026 compared to the six months ended June 30, 2025. This was primarily attributable to higher manufacturing activity for process performance qualification batches of oligonucleotide payload and the timing of drug substance conjugation activities in the six months ended June 30, 2025, which were partially offset by higher clinical costs in the six months ended June 30, 2026 due to the completion of enrollment of the registrational expansion cohort of the ACHIEVE trial in the second quarter of 2026 and increased enrollment in the HARMONIA trial.

Current wording

Expenses related to z-rostudirsen increased in the nine months ended September 30, 2026 compared to the nine months ended September 30, 2025. This was attributable to increased manufacturing activity of drug substance and components in the nine months ended September 30, 2026, primarily for clinical supply for the long-term extension of the DELIVER trial and the FORZETTO trial. Additionally, higher clinical costs were incurred in the nine months ended September 30, 2026 due to increased activity in the FORZETTO trial. Expenses related to z-basivarsen decreased in the nine months ended September 30, 2026 compared to the nine months ended September 30, 2025. This was primarily attributable to higher manufacturing activity for process performance qualification batches of oligonucleotide payload and the timing of drug substance conjugation activities in the nine months ended September 30, 2025, which were partially offset by higher clinical costs in the nine months ended September 30, 2026 due to the ongoing registrational expansion cohort of the ACHIEVE trial and increased enrollment in the HARMONIA trial.

Previous wording

The increase in platform and external research and development expenses in the six months ended June 30, 2026 compared to the six months ended June 30, 2025 was primarily due to increased external research activity associated with our preclinical programs and product candidates. The increase in personnel-related expenses was primarily due to the increase of 39 employees in our research and development headcount and higher stock-based compensation expense for awards granted to new hires and existing employees. The increase in facility-related and other expenses was primarily due to the increased costs of supporting a larger number of research and development personnel.

Current wording

The increase in platform and external research and development expenses in the nine months ended September 30, 2026 compared to the nine months ended September 30, 2025 was primarily due to increased external research activity associated with our preclinical programs and product candidates. The increase in personnel-related expenses was primarily due to the increase of 35 employees in our research and development headcount and higher stock-based compensation expense for awards granted to new hires and existing employees. The increase in facility-related and other expenses was primarily due to the increased costs of supporting a larger number of research and development personnel.

Previous wording

The following table summarizes our general and administrative expenses for the six months ended June 30, 2026 and 2025:

Current wording

The following table summarizes our general and administrative expenses for the nine months ended September 30, 2026 and 2025:

Previous wording

The increase in personnel-related and stock-based compensation expenses in the six months ended June 30, 2026 compared to the six months ended June 30, 2025 was due to the increase of 44 employees in our general and administrative headcount. Professional and consulting fees increased due to higher consulting costs for the preparation activities for the potential launch of z-rostudirsen and the overall growth of the organization in the six months ended June 30, 2026. Facility-related and other expenses increased due to higher costs of supporting a larger number of general and administrative personnel in the six months ended June 30, 2026.

Current wording

The increase in personnel-related and stock-based compensation expenses in the nine months ended September 30, 2026 compared to the nine months ended September 30, 2025 was due to the increase of 47 employees in our general and administrative headcount. Professional and consulting fees increased due to higher consulting costs for the preparation activities for the potential launch of z-rostudirsen and the overall growth of the organization in the nine months ended September 30, 2026. Facility-related and other expenses increased due to higher costs of supporting a larger number of general and administrative personnel in the nine months ended September 30, 2026.

Previous wording

Interest income for the six months ended June 30, 2026 and 2025 was $16.5 million and $13.7 million, respectively, due to interest earned on invested cash balances. The increase in interest income was due to an increased cash, cash equivalents and marketable securities balance throughout the six months ended June 30, 2026 compared to the six months ended June 30, 2025.

Current wording

Interest income for the nine months ended September 30, 2026 and 2025 was $26.3 million and $22.2 million, respectively, due to interest earned on invested cash balances. The increase in interest income was due to an increased cash, cash equivalents and marketable securities balance throughout the nine months ended September 30, 2026 compared to the nine months ended September 30, 2025.

Previous wording

Interest expense for the six months ended June 30, 2026 was $8.8 million due to our Loan Agreement with Hercules and interest owed on our vendor financing arrangement. Interest expense for the six months ended June 30, 2025 was less than $0.1 million due to our Loan Agreement with Hercules.

Current wording

Interest expense for the nine months ended September 30, 2026 was $14.7 million due to our Loan Agreement with Hercules and interest owed on our vendor financing arrangement. Interest expense for the nine months ended September 30, 2025 was $3.0 million due to our Loan Agreement with Hercules.

Previous wording

Other expense for the six months ended June 30, 2026 and 2025 was $0.2 million and $1.7 million, respectively, due to realized foreign currency losses.

Current wording

Other expense for the nine months ended September 30, 2026 and 2025 was $0.5 million and $1.4 million, respectively, due to realized foreign currency losses.

Previous wording

Since our inception, we have incurred significant operating losses. We expect to incur significant expenses and operating losses for the foreseeable future as we support our continued research activities and development of our product candidates and platform. We have not yet commercialized any product candidates, and we do not expect to generate revenue from sales of any product candidates at least until 2027, if at all. To date, we have funded our operations primarily with proceeds from sales of equity securities and our borrowing under the Loan Agreement with Hercules. As of June 30, 2026 we had cash, cash equivalents and marketable securities of $898.5 million.

Current wording

Since our inception, we have incurred significant operating losses. We expect to incur significant expenses and operating losses for the foreseeable future as we support our continued research activities and development of our product candidates and platform. We have not yet commercialized any product candidates, and we do not expect to generate revenue from sales of any product candidates at least until 2027, if at all. To date, we have funded our operations primarily with proceeds from sales of equity securities and our borrowings under the Loan Agreement with Hercules. As of September 30, 2026 we had cash, cash equivalents and marketable securities of $1.134 billion.

Previous wording

In November 2021, we entered into an Open Market Sale Agreement SM, or the Sales Agreement, with Jefferies LLC, or Jefferies. On March 5, 2024, we filed a universal shelf registration statement on Form S-3, or the 2024 Shelf Registration Statement, and included a prospectus relating to the Sales Agreement. Under the 2024 Shelf Registration Statement, we may offer and sell debt securities, common stock, preferred stock, units and/or warrants from time to time at an indeterminate aggregate offering price in one or more offerings. In November 2024, we filed a prospectus supplement relating to the Sales Agreement, pursuant to which, in accordance with the Sales Agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $300.0 million, which we refer to as our at-the-market offering program. Sales of common stock under the Sales Agreement through Jefferies may be made by any method that is deemed an “at-the-market” offering as defined in Rule 415(a)(4) under the Securities Act. During the six months ended June 30, 2026, we did not issue or sell any shares of common stock pursuant to the Sales Agreement.

Current wording

In November 2021, we entered into an Open Market Sale Agreement SM, or the Sales Agreement, with Jefferies LLC, or Jefferies. On March 5, 2024, we filed a universal shelf registration statement on Form S-3, or the 2024 Shelf Registration Statement, and included a prospectus relating to the Sales Agreement. Under the 2024 Shelf Registration Statement, we may offer and sell debt securities, common stock, preferred stock, units and/or warrants from time to time at an indeterminate aggregate offering price in one or more offerings. In November 2024, we filed a prospectus supplement relating to the Sales Agreement, pursuant to which, in accordance with the Sales Agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $300.0 million, which we refer to as our at-the-market offering program. Sales of common stock under the Sales Agreement through Jefferies may be made by any method that is deemed an “at-the-market” offering as defined in Rule 415(a)(4) under the Securities Act. During the nine months ended September 30, 2026, we did not issue or sell any shares of common stock pursuant to the Sales Agreement.

Previous wording

In July 2026, we completed the July 2026 offering, pursuant to which we issued and sold 21,045,000 shares of our common stock. We estimate that the net proceeds from the offering were approximately $405.0 million, after deducting underwriting discounts and commissions and offering expenses payable by us.

Current wording

In July 2026, we completed a follow-on public offering, or the July 2026 Offering, pursuant to which we issued and sold 21,045,000 shares of our common stock. Net proceeds from the July 2026 Offering were approximately $404.9 million, after deducting underwriting discounts and commissions and offering expenses payable by us.

Previous wording

During the six months ended June 30, 2026, operating activities used $275.2 million of cash, due to our net loss of $299.4 million and net cash used by changes in our operating assets and liabilities of $4.8 million, partially offset by non-cash charges of $29.0 million. Net cash used in changes in our operating assets and liabilities primarily consisted of a $23.4 million increase in prepaid expenses and other current assets, partially offset by a $14.2 million increase in accounts payable and other liabilities and a $4.4 million decrease in other non-current assets. During the six months ended June 30, 2025, operating activities used $200.6 million of cash, due to our net loss of $226.2 million, partially offset by non-cash charges of $23.6 million and net cash provided by changes in our operating assets and liabilities of $2.0 million. Net cash provided by changes in our operating assets and liabilities primarily consisted of a $2.8 million decrease in prepaid expenses and other current assets, partially offset by a $0.8 million decrease in accounts payable and other liabilities. Changes in our operating assets and liabilities during these periods were generally due to the growth of our business, increased clinical trial activity, increased manufacturing activities, advancement of our product candidates and the timing of vendor invoices and payments.

Current wording

During the nine months ended September 30, 2026, operating activities used $452.7 million of cash, due to our net loss of $493.0 million and net cash used by changes in our operating assets and liabilities of $5.8 million, partially offset by non-cash charges of $46.0 million. Net cash used in changes in our operating assets and liabilities primarily consisted of a $25.7 million increase in prepaid expenses and other current assets, partially offset by a $15.9 million increase in accounts payable and other liabilities and a $4.1 million decrease in other non-current assets. During the nine months ended September 30, 2025, operating activities used $291.4 million of cash, due to our net loss of $334.3 million, partially offset by non-cash charges of $35.0 million and net cash provided by changes in our operating assets and liabilities of $7.9 million. Net cash provided by changes in our operating assets and liabilities primarily consisted of a $17.7 million increase in accounts payable and other liabilities and a $3.2 million decrease in prepaid expenses and other current assets, partially offset by a $13.0 million increase in other non-current assets. Changes in our operating assets and liabilities during these periods were generally due to the growth of our business, increased clinical trial activity, increased manufacturing activities, advancement of our product candidates and the timing of vendor invoices and payments.

Previous wording

During the six months ended June 30, 2026, net cash used in investing activities was $7.2 million due to purchases of marketable securities of $107.1 million and purchases of property and equipment of $1.7 million, partially offset by maturities of marketable securities of $58.2 million and sales of marketable securities of $43.4 million. During the six months ended June 30, 2025, net cash provided by investing activities was $8.2 million due to maturities of marketable securities of $107.7 million and sales of marketable securities of $8.5 million, partially offset by purchases of marketable securities of $106.9 million and purchases of property and equipment of $1.0 million.

Current wording

During the nine months ended September 30, 2026, net cash used in investing activities was $8.5 million due to purchases of marketable securities of $158.6 million and purchases of property and equipment of $3.7 million, partially offset by maturities of marketable securities of $92.7 million and sales of marketable securities of $61.2 million. During the nine months ended September 30, 2025, net cash used in investing activities was $29.7 million due to purchases of marketable securities of $153.8 million, an advance payment for long-lead equipment for $18.8 million, which was transferred to other non-current assets and is expected to be credited towards future batch manufacturing fees as of September 30, 2026, and purchases of property and equipment of $1.4 million, partially offset by maturities of marketable securities of $135.8 million and sales of marketable securities of $8.5 million.

Previous wording

During the six months ended June 30, 2026, net cash provided by financing activities was $65.2 million, including $49.5 million in net proceeds from the third term loan tranche under our Loan Agreement with Hercules, $18.0 million in proceeds from our vendor financing arrangement and $2.0 million in proceeds received from stock option exercises. These cash inflows were partially offset by $3.9 million in repayments related to our vendor financing arrangement and the payment of $0.4 million of issuance costs from the follow-on public offering we completed in December 2025, pursuant to which we issued and sold 21,827,549 shares of our common stock and from which we received net proceeds of $377.7 million, after deducting underwriting discounts and commissions and offering expenses paid by us. During the six months ended June 30, 2025, net cash provided by financing activities was $242.0 million, consisting of $140.6 million in aggregate net proceeds from sales of our common stock under our at-the-market offering program, $98.8 million in net proceeds from the initial term loan tranche under the Loan Agreement with Hercules and $2.6 million in net proceeds received from stock option exercises.

Current wording

During the nine months ended September 30, 2026, net cash provided by financing activities was $483.3 million, including $404.9 million in net proceeds after deducting underwriting discounts and commissions and offering expenses paid by us from the July 2026 Offering, pursuant to which we issued and sold 21,045,000 shares of our common stock, $49.5 million in net proceeds from the third term loan tranche under our Loan Agreement with Hercules, $34.9 million in proceeds from our vendor financing arrangement and $4.1 million in proceeds received from stock option exercises. These cash inflows were partially offset by $9.6 million in repayments related to our vendor financing arrangement and the payment of $0.4 million of issuance costs from the follow-on public offering we completed in December 2025. During the nine months ended September 30, 2025, net cash provided by financing activities was $459.3 million, consisting of $215.8 million in aggregate net proceeds from sales of common stock under our follow-on offering in July 2025, $140.7 million in aggregate net proceeds from sales of our common stock under our at-the-market offering program, $98.8 million in net proceeds from the initial term loan tranche under the Loan Agreement with Hercules and $4.6 million in net proceeds received from stock option exercises. These cash inflows were partially offset by $0.5 million in payment of debt issuance costs.

Previous wording

We believe that our cash, cash equivalents and marketable securities as of June 30, 2026, as well as the approximately $405.0 in net proceeds from the July 2026 offering, will enable us to fund our operating expenses, debt service obligations, and capital expenditure requirements into the second quarter of 2028. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect.

Current wording

We believe that our cash, cash equivalents and marketable securities as of September 30, 2026 will enable us to fund our operating expenses, debt service obligations, and capital expenditure requirements into the second quarter of 2028. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect.

Previous wording

We have also entered into a license agreement with the University of Mons under which we are obligated to make specified milestone and royalty payments. The payment obligations under this agreement are contingent upon future events, such as our achievement of specified development, regulatory and commercial milestones, or generating product sales. We are unable to estimate the timing or likelihood of achieving these milestones or generating future product sales. For additional information about our license agreement with the University of Mons and amounts that could become payable in the future under that agreement, see Item 1. "Business—Intellectual Property—License Agreement with the University of Mons" in the Annual Report on Form 10-K filed with the SEC on March 2, 2026.

Current wording

We have also entered into a license agreement with the University of Mons under which we are obligated to make specified milestone and royalty payments. The payment obligations under this agreement are contingent upon future events, such as our achievement of specified development, regulatory and commercial milestones, or generating product sales. We are unable to estimate the timing or likelihood of achieving these milestones or generating future product sales.

Previous wording

On January 15, 2025, we entered into a master manufacturing services agreement with a CMO which secures capacity at the CMO's manufacturing facilities for certain of our product candidates and components thereof. As of June 30, 2026, we have paid $26.9 million towards non-current assets under this agreement and pursuant to a mutually agreed rolling forecast we have committed to pay an additional $99.7 million in fees through June 2028. In specified termination circumstances, the agreement requires us to pay the CMO for services completed, the cost of the CMO's raw materials that cannot be repurposed and specified cancellation fees. This agreement formalizes and supersedes a letter agreement that we entered into with the CMO on July 18, 2024.

Current wording

On January 15, 2025, we entered into a master manufacturing services agreement with a CMO which secures capacity at the CMO's manufacturing facilities for certain of our product candidates and components thereof. As of September 30, 2026, we have paid $27.2 million towards non-current assets under this agreement and pursuant to a mutually agreed rolling forecast we have committed to pay an additional $69.4 million in fees through September 2028. In specified termination circumstances, the agreement requires us to pay the CMO for services completed, the cost of the CMO's raw materials that cannot be repurposed and specified cancellation fees. This agreement formalizes and supersedes a letter agreement that we entered into with the CMO on July 18, 2024.

Previous wording

On October 31, 2025, we entered into another master manufacturing services agreement with a CMO which also secures capacity at the CMO's manufacturing facilities for certain of our product candidate components. The agreement obligates us to compensate the CMO for producing certain of our product candidate components pursuant to a mutually agreed rolling forecast, pursuant to which, as of June 30, 2026, we have committed to pay an additional $59.8 million in fees through December 2027. In specified termination circumstances, the agreement requires us to pay the CMO for services completed, the cost of the CMO's raw materials that cannot be repurposed, capital equipment and certain manufacturing activities previously committed to.

Current wording

On October 31, 2025, we entered into another master manufacturing services agreement with a CMO which also secures capacity at the CMO's manufacturing facilities for certain of our product candidate components. The agreement obligates us to compensate the CMO for producing certain of our product candidate components pursuant to a mutually agreed rolling forecast, pursuant to which, as of September 30, 2026, we have committed to pay an additional $53.3 million in fees through March 2028. In specified termination circumstances, the agreement requires us to pay the CMO for services completed, the cost of the CMO's raw materials that cannot be repurposed, capital equipment and certain manufacturing activities previously committed to.