Dyne Therapeutics, Inc.

Previous wording

We are a clinical-stage muscle disease company focused on advancing innovative life-transforming therapeutics for people living with genetically driven diseases. We are utilizing our proprietary FORCE platform to overcome the current limitations of muscle tissue delivery and advance modern oligonucleotide therapeutics for muscle diseases. Our proprietary FORCE platform therapeutics consist of an oligonucleotide payload that we rationally design to target the genetic basis of the disease we are seeking to treat, a clinically validated linker and an antigen-binding fragment, or Fab, that we attach to the payload using the linker. With our FORCE platform, we have the flexibility to deploy different types of oligonucleotide payloads with specific mechanisms of action that modify target functions. We leverage this modularity to focus on muscle diseases with high unmet need, with etiologic targets and with clear translational potential from preclinical disease models to well-defined clinical development and regulatory pathways.

Current wording

We are a clinical-stage company focused on discovering and advancing innovative life-transforming therapeutics for people living with genetically driven neuromuscular diseases. Leveraging the modularity of our FORCE platform, we are developing targeted therapeutics that are designed to overcome limitations in delivery to muscle tissue and the central nervous system, or CNS. Our proprietary FORCE platform therapeutics consist of a payload that we rationally design to target the genetic basis of the disease we are seeking to treat, a linker and an antigen-binding fragment, or Fab, that we attach to the payload using the linker. With our FORCE platform, we have the flexibility to deploy different classes of payloads (such as oligonucleotides and enzymes) with specific mechanisms of action that modify target functions. We leverage this modularity to focus on neuromuscular diseases with high unmet need, with etiologic targets and with clear translational potential from preclinical disease models to well-defined clinical development and regulatory pathways.

Previous wording

Using our FORCE platform, we are assembling a broad portfolio of muscle disease therapeutics, including our programs in myotonic dystrophy type 1, or DM1, Duchenne muscular dystrophy, or DMD, and facioscapulohumeral dystrophy, or FSHD. In addition, we plan to expand our portfolio through development efforts focused on rare skeletal muscle diseases, as well as cardiac and metabolic muscle diseases, including some with larger patient populations, and diseases involving the central nervous system, or CNS. We have identified product candidates for each of our DM1, DMD and FSHD programs that are in varying stages of preclinical and clinical development.

Current wording

Using our FORCE platform, we are assembling a broad portfolio of product candidates, including product candidates being developed for myotonic dystrophy type 1, or DM1, Duchenne muscular dystrophy, or DMD, facioscapulohumeral dystrophy, or FSHD, and Pompe disease. In addition, we plan to expand our portfolio through development efforts focused on rare skeletal muscle diseases, as well as cardiac and metabolic muscle diseases, including some with larger patient populations, and diseases involving the CNS. We have identified product candidates for each of our DM1, DMD, FSHD and Pompe programs that are in varying stages of preclinical and clinical development.

Previous wording

In the MAD portion of the ACHIEVE trial, patients are randomized to receive DYNE-101 or placebo intravenously every four weeks or every eight weeks for 24 weeks, depending on cohort. Patient cohorts will be dosed from 1.8 mg/kg to 10.2 mg/kg (approximate antisense oligonucleotide, or ASO, dose). Following the placebo-controlled period, patients transition to DYNE-101 treatment in the OLE portion of the trial and in the long-term extension.

Current wording

Our product candidate DYNE-101 is being evaluated in the ACHIEVE trial, a global Phase 1/2 clinical trial consisting of a 24-week multiple ascending dose, or MAD, randomized, placebo-controlled period, a 24-week open-label extension, or OLE, a 96-week long-term extension, and a registrational expansion cohort. The primary endpoints of the MAD portion of the trial were safety and tolerability; with secondary endpoints of pharmacokinetics and pharmacodynamics, including change from baseline in splicing as measured by the composite alternative splicing index, or CASI-22, as well as multiple measures of muscle strength and function and patient-reported outcomes, including the Myotonic Dystrophy Health Index. In the MAD portion of the ACHIEVE trial, patients were randomized to receive DYNE-101 or placebo intravenously every four weeks or every eight weeks for 24 weeks, depending on cohort. Patient cohorts were dosed from 1.8 mg/kg to 6.8 mg/kg (approximate ASO dose). Following the MAD placebo-controlled period, patients transition to DYNE-101 treatment in the OLE portion of the trial and in the long-term extension.

Previous wording

Our product candidate DYNE-251 is being evaluated in DELIVER, an ongoing Phase 1/2 global clinical trial in patients with DMD who have mutations amenable to exon 51 skipping, consisting of a 24-week MAD randomized, placebo-controlled period, a 24-week OLE and a 96-week long-term extension. DELIVER, which is designed to be registrational, is enrolling ambulant and non-ambulant males with DMD who are ages 4 to 16 and have mutations amenable to exon 51 skipping. The primary endpoints are safety, tolerability and change from baseline in dystrophin levels as measured by Western blot. Additional endpoints include pharmacokinetics and change from baseline in exon 51 skipping levels, muscle tissue percent dystrophin positive fibers (PDPF), multiple assessments of muscle function, including North Star Ambulatory Assessment (NSAA) score, Stride Velocity 95th Centile and certain timed functional tests.

Current wording

Our product candidate DYNE-251 is currently being evaluated in the DELIVER trial, a Phase 1/2 global clinical trial consisting of a 24-week MAD randomized, placebo-controlled period, a 24-week OLE, and a 192-week long-term extension, and a registrational expansion cohort. The trial, which is designed to be registrational, enrolled ambulant and non-ambulant males with DMD who are ages 4 to 16 and have mutations amenable to exon 51 skipping. The primary endpoints of the MAD portion were safety, tolerability and change from baseline in dystrophin levels as measured by Western blot. Additional endpoints in the MAD portion of the trial included pharmacokinetics and change from baseline in exon 51 skipping levels, muscle tissue percent dystrophin positive fibers, multiple assessments of muscle function, including North Star Ambulatory Assessment score, Stride Velocity 95th Centile and certain timed functional tests.

Previous wording

In the MAD portion of the DELIVER trial, patients are randomized to receive DYNE-251 or placebo every four or eight weeks intravenously for 24 weeks, depending on cohort. Patients have been dosed in cohorts from 0.7 mg/kg to 40 mg/kg (approximate phosphorodiamidate morpholino oligomer, or PMO, dose). Following the placebo-controlled period, patients transition to DYNE-251 treatment in the open-label portion of the trial and in the long-term extension.

Current wording

In the MAD portion of the DELIVER trial, patients were randomized to receive DYNE-251 or placebo every four or eight weeks intravenously for 24 weeks, depending on cohort. Patients cohorts were dosed from 0.7 mg/kg to 20 mg/kg (approximate PMO dose). Following the placebo-controlled period, patients transition to DYNE-251 treatment in the open-label portion of the trial and in the long-term extension.

Previous wording

In September 2024, we announced positive clinical data from the DELIVER trial. The efficacy assessment of the DYNE-251 DELIVER trial reported in September 2024 was based on 6-month biomarker and functional data from eight male patients with DMD amenable to exon 51 skipping enrolled in the 20 mg/kg (approximate PMO dose) cohort of the randomized, placebo-controlled MAD portion of the trial and 12-month functional data from six male patients enrolled in the 10 mg/kg (approximate PMO dose) cohort. During the open label extension period, all participants in the 10 mg/kg cohort were dose escalated to 20 mg/kg Q4W regimen. DYNE-251 demonstrated dose-dependent exon skipping and dystrophin expression and improvement in multiple functional endpoints in both cohorts. In these data, DYNE-251 reached levels of dystrophin expression that exceeded levels reported in a third-party clinical trial for the current weekly standard of care for DMD exon 51, eteplirsen, at 6 months with a significantly lower PMO dose. In these data, DYNE-251 also demonstrated encouraging trends in multiple functional endpoints.

Current wording

In March 2025, we reported positive long-term safety and efficacy data from the MAD portion of the DELIVER trial. The efficacy assessment of the DELIVER trial reported in March 2025 was based on 12-month biomarker and functional data from six male patients enrolled in the 20 mg/kg (approximate PMO dose) cohort who were randomized to receive DYNE-251 or placebo once every four weeks, or Q4W, and 18-month functional data from six male patients in the 10 mg/kg (approximate PMO dose) cohort who were randomized to receive DYNE-251 or placebo Q4W. During the open label extension period, all participants in the 10 mg/kg cohort were dose escalated to 20 mg/kg Q4W regimen after month six. DYNE-251 demonstrated dose-dependent exon skipping and dystrophin expression and meaningful and sustained improvements from baseline in multiple functional endpoints in both cohorts. In the 20 mg/kg Q4W cohort, DYNE-251 demonstrated best-in-class levels of dystrophin expression, exon skipping and percent dystrophin.

Previous wording

Safety and tolerability data from the assessment of the DELIVER trial reported in September 2024 were based on 54 participants enrolled in the DELIVER trial. As of the safety data cut-off date of August 21, 2024, DYNE-251 demonstrated a favorable safety profile and the majority of treatment emergent adverse events were mild or moderate and no related serious treatment emergent adverse events were identified other than in two participants at the 40 mg/kg dose level which events were potentially related to study drug. One participant experienced symptoms which suggested hemolytic uremic syndrome with potentially caused by an infection. The second participant had a history of unexplained hemolytic anemia and developed fever and tonsillitis after joining the DELIVER trial. Both participants have recovered.

Current wording

In March 2025, we also reported updated safety and tolerability data based on 54 participants enrolled in the DELIVER trial. As of the data cutoff date of February 7, 2025, DYNE-251 demonstrated a favorable safety profile and the majority of treatment emergent adverse events were mild or moderate and no related serious treatment emergent adverse events were identified other than in two participants at the 40 mg/kg Q4W dose level which events were potentially related to study drug. One participant experienced symptoms which suggested hemolytic uremic syndrome, potentially caused by an infection. The second participant had a history of unexplained hemolytic anemia and developed fever and tonsillitis after joining the DELIVER trial. Both participants have recovered.

Previous wording

Based on these data, we have begun enrolling a 20 mg/kg Q4W (approximate PMO dose) registrational cohort of 32 participants as part of the DELIVER trial. We continue to pursue expedited approval pathways for DYNE-251, including accelerated approval in the U.S. based on dystrophin as a surrogate endpoint.

Current wording

We completed enrollment of the 20 mg/kg Q4W (approximate PMO dose) registrational expansion cohort of 32 participants as part of the DELIVER trial in the first quarter of 2025 and are planning for data from this cohort in late 2025 and potential submission for U.S. Accelerated Approval in early 2026. We continue to pursue accelerated approval in the U.S. based on dystrophin as a surrogate endpoint. We are also pursuing expedited approval pathways globally for DYNE-251.

Previous wording

In June 2024, we announced new preclinical data for DYNE-302, our product candidate for FSHD, that demonstrated robust and durable DUX4 suppression and functional benefit in a mouse model. We generated data using an innovative hTfR1/iFLExD mouse model we developed that expresses the human transferrin 1 receptor, or TfR1, and enables tunable DUX4 induction in skeletal muscle. In hTfR1/iFLExD mice, a single intravenous dose of DYNE-302 resulted in dose-dependent and robust reduction of the DUX4 transcriptome that lasted up to three months, with benefit on muscle structure and function. DYNE-302 also demonstrated high in vitro potency in FSHD patient-derived myotubes. We are progressing DYNE-302 through IND/CTA-enabling studies.

Current wording

In June 2024, we announced new preclinical data for DYNE-302, our product candidate for FSHD, that demonstrated robust and durable DUX4 suppression and functional benefit in a mouse model. We generated these data using an innovative hTfR1/iFLExD mouse model we developed that expresses the human transferrin 1 receptor, or TfR1, and enables tunable DUX4 induction in skeletal muscle. In hTfR1/iFLExD mice, a single intravenous dose of DYNE-302 resulted in dose-dependent and robust reduction of the DUX4 transcriptome that lasted up to three months, with benefit on muscle structure and function. DYNE-302 also demonstrated high in vitro potency in FSHD patient-derived myotubes. We are progressing DYNE-302 through IND/CTA-enabling studies.

Previous wording

We were incorporated and commenced operations in 2017. Since our inception, 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.

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.

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 nine months ended September 30, 2024 and 2023, we reported net losses of $227.9 million and $169.3 million, respectively. As of September 30, 2024, we had an accumulated deficit of $860.4 million.

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 three months ended March 31, 2025 and 2024, we reported net losses of $115.4 million and $65.6 million, respectively. As of March 31, 2025, we had an accumulated deficit of $1.1 billion.

Previous wording

advance our product candidates for DM1, DMD and FSHD and conduct research programs in additional indications;

Current wording

advance our product candidates for DM1, DMD, FSHD and Pompe and conduct research programs in additional indications;

Previous wording

establish manufacturing sources for any product candidate we may develop, including the Fab antibody, Val-cit linker and therapeutic payload that will comprise the product candidate, and secure supply chain capacity to provide sufficient quantities for preclinical and clinical development and commercial supply;

Current wording

establish manufacturing sources for any product candidate we may develop, including the Fab antibody, linkers and therapeutic payload that will comprise the product candidate, and secure supply chain capacity to provide sufficient quantities for preclinical and clinical development and commercial supply;

Previous wording

We have not generated any revenue since our inception and do not expect to generate any revenue from the sale of products in the near future, if at all. If our development efforts are successful and we commercialize products, or if we enter into collaboration or license agreements with third parties, we may generate revenue in the future from product sales, as well as upfront, milestone and royalty payments from such collaboration or license agreements, or a combination thereof.

Current wording

We have not generated any revenue since our inception and do not expect to generate any revenue from the sale of products for at least a couple of years, if at all. If our development efforts are successful and we commercialize products, or if we enter into collaboration or license agreements with third parties, we may generate revenue in the future from product sales, as well as upfront, milestone and royalty payments from such collaboration or license agreements, or a combination thereof.

Previous wording

Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. Accordingly, we expect that our research and development expenses will increase substantially as we advance DYNE-101 and DYNE-251 through clinical trials and in connection with our preclinical and clinical development activities if and as we advance any other product candidates through preclinical studies and clinical trials. 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. The successful development of any product candidate is highly uncertain. This is due to the numerous risks and uncertainties associated with product development, including the following:

Current wording

Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. Accordingly, we expect that our research and development expenses will increase substantially as we advance DYNE-101 and DYNE-251 through clinical trials, in connection with our preclinical and clinical development activities of DYNE-302, our FSHD product candidate, and DYNE-401, our Pompe disease product candidate, and if, and as, we advance any other product candidates through preclinical studies and clinical trials. 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. The successful development of any product candidate is highly uncertain. This is due to the numerous risks and uncertainties associated with product development, including the following:

Previous wording

Since our inception, we have not recorded any U.S. federal or state income tax benefits for the net losses we have incurred in any year or for our earned research and development tax credits, due to the uncertainty of realizing a benefit from those items.

Current wording

Since our inception, we have not recorded any U.S. federal or state income tax benefits for the net losses we have incurred in any year or for our earned research and development tax credits, due to our uncertainty of realizing a benefit from those items.

Previous wording

Expenses related to DYNE-101 increased in the nine months ended September 30, 2024 compared to the nine months ended September 30, 2023. This was attributable to higher manufacturing activity and an increase in clinical trial activity for the ACHIEVE trial in the nine months ended September 30, 2024. Expenses related to DYNE-251 increased in the nine months ended September 30, 2024 compared to the nine months ended September 30, 2023. This was attributable to higher manufacturing activity and an increase in clinical trial activity for the DELIVER trial in the nine months ended September 30, 2024.

Current wording

Expenses related to DYNE-101 increased in the three months ended March 31, 2025 compared to the three months ended March 31, 2024. This was attributable to higher manufacturing activity in the three months ended March 31, 2025 to produce a sufficient clinical supply of drug product for the ongoing ACHIEVE trial and an increase in clinical trial activity for the ACHIEVE trial. Expenses related to DYNE-251 increased in the three months ended March 31, 2025 compared to the three months ended March 31, 2024. This was attributable to higher manufacturing activity in the three months ended March 31, 2025 to produce a sufficient clinical supply of drug product for the ongoing DELIVER trial and an increase in clinical trial activity for the DELIVER trial.

Previous wording

The increase in platform and external research and development expenses in the nine months ended September 30, 2024 compared to the nine months ended September 30, 2023 was primarily due to increased external research activity associated with our preclinical programs. The increase in personnel-related expenses and stock-based compensation expense was primarily due to increased headcount in our research and development function. 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 March 31, 2025 compared to the three months ended March 31, 2024 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 increased headcount in our research and development function. 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 expenses in the nine months ended September 30, 2024 compared to the nine months ended September 30, 2023 was due to increased headcount in our general and administrative function. The increase in stock-based compensation expense was primarily the result of acceleration of vesting terms and modification of previously granted awards in connection with entering into separation and consulting agreements with our former chief executive officer and former chief business officer. The increase in professional and consulting fees was primarily due to higher intellectual property related legal costs associated with our patent portfolio and other professional fees. Facility-related and other expenses remained generally consistent in the nine months ended September 30, 2024 compared to the nine months ended September 30, 2023.

Current wording

The increase in personnel-related expenses in the three months ended March 31, 2025 compared to the three months ended March 31, 2024 was due to increased headcount in our general and administrative function. The decrease in stock-based compensation expense in the three months ended March 31, 2025 compared to the three months ended March 31, 2024 was attributable to entering into separation and consulting agreements with our former chief executive officer in March 2024, resulting in the acceleration of vesting and modification of previously granted equity awards in the three months ended March 31, 2024. Professional and consulting fees increased due to the higher consulting costs to support the growth of the organization in the three months ended March 31, 2025. 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 March 31, 2025.

Previous wording

Interest income for the three months ended September 30, 2024 and 2023 was $9.3 million and $2.2 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 on which we are earning interest due to the sale of common stock in the first and second quarters of 2024.

Current wording

Interest income for the three months ended March 31, 2025 and 2024 was $7.1 million and $3.0 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 due to the public sales of common stock in the three months ended March 31, 2025.

Previous wording

Other income for the nine months ended September 30, 2024 was $0.4 million due to net foreign currency losses, partially offset by realized gains on the sales of marketable securities. Other expense for the nine months ended September 30, 2023 was $0.7 million due to realized losses on the sale of marketable securities and net foreign currency losses.

Current wording

Other expense for the three months ended March 31, 2025 was $0.1 million due to net foreign currency gains and losses. Other income for the three months ended March 31, 2024 was and $0.5 million due to net foreign currency gains and 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 for several years, if at all. To date, we have funded our operations primarily with proceeds from sales of equity securities. As of September 30, 2024 we had cash, cash equivalents and marketable securities of $723.7 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 for at least a couple of years, if at all. To date, we have funded our operations primarily with proceeds from sales of equity securities. As of March 31, 2025 we had cash, cash equivalents and marketable securities of $677.5 million.

Previous wording

In November 2021, we filed a universal shelf registration statement on Form S-3, or the 2021 Shelf Registration Statement, to register for sale from time to time up to $400.0 million of common stock, preferred stock, debt securities, warrants and/or units in one or more offerings. Further, in November 2021, we entered into an Open Market Sale Agreement SM, or the Sales Agreement, with Jefferies LLC, or Jefferies, and included in the 2021 Shelf Registration Statement a prospectus relating to the Sales Agreement pursuant to which, from time to time, we could offer and sell shares of our common stock having an aggregate offering price of up to $150.0 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 of 1933, as amended, or Securities Act. On January 4, 2024, we notified Jefferies that we were suspending and terminating the prospectus filed under our 2021 Shelf Registration Statement relating to the Sales Agreement for our at-the-market offering program.

Current wording

In November 2021, we filed a universal shelf registration statement on Form S-3, or the 2021 Shelf Registration Statement, to register for sale from time to time up to $400.0 million of common stock, preferred stock, debt securities, warrants and/or units in one or more offerings. Further, in November 2021, we entered into an Open Market Sale Agreement SM, or the Sales Agreement, with Jefferies LLC, or Jefferies, and included in the 2021 Shelf Registration Statement a prospectus relating to the Sales Agreement, pursuant to which, from time to time, we may offer and sell shares of our common stock having an aggregate offering price of up to $150.0 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 of 1933, as amended, or Securities Act. On January 4, 2024, we notified Jefferies that we were suspending and terminating the prospectus filed under our 2021 Shelf Registration Statement relating to the Sales Agreement for our at-the-market offering program.

Previous wording

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, or the 2024 ATM Prospectus. 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. Under the 2024 ATM Prospectus, in accordance with the Sales Agreement, we may offer and sell shares having an aggregate offering price of up to $200.0 million.

Current wording

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 in our at-the-market offering program.

Previous wording

During the nine months ended September 30, 2024, we issued and sold an aggregate of 3,800,465 shares of common stock pursuant to the Sales Agreement for aggregate net proceeds of $97.9 million, after deducting sales agent commissions and offering expenses payable by us. We sold such shares at a weighted average price of $26.86 per share.

Current wording

During the three months ended March 31, 2025, we issued and sold an aggregate of 10,660,159 shares of common stock pursuant to the Sales Agreement for aggregate net proceeds of $140.6 million, after deducting commissions and offering expenses payable by us. We sold such shares at a weighted average price of $13.60 per share.

Previous wording

During the nine months ended September 30, 2024, operating activities used $208.0 million of cash, due to our net loss of $227.9 million and net cash used by changes in our operating assets and liabilities of $14.4 million, partially offset by non-cash charges of $34.2 million. Net cash used by changes in our operating assets and liabilities consisted of a $8.0 million decrease in accounts payable and other liabilities and a $6.4 million increase in prepaid expenses. During the nine months ended September 30, 2023, operating activities used $153.2 million of cash, due to our net loss of $169.3 million, partially offset by partially offset by non-cash charges of $15.4 million and net cash provided by changes in our operating assets and liabilities of $0.8 million. Net cash provided by changes in our operating assets and liabilities consisted of a $1.6 million increase in accounts payable and other liabilities, partially offset by a $0.8 million increase in prepaid expenses. 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, the timing of vendor invoices and payments and annual bonus payments.

Current wording

During the three months ended March 31, 2025, operating activities used $105.9 million of cash, due to our net loss of $115.4 million and changes in our operating assets and liabilities of $3.6 million, partially offset by non-cash charges of $13.1 million. Net cash used in changes in our operating assets and liabilities primarily consisted of a $8.6 million decrease in accounts payable and other liabilities and a $5.0 million decrease in prepaid expenses and other assets. During the three months ended March 31, 2024, operating activities used $78.5 million of cash, due to our net loss of $65.6 million and net cash used by changes in our operating assets and liabilities of $32.8 million, partially offset by non-cash charges of $19.9 million. Net cash used by changes in our operating assets and liabilities primarily consisted of a $28.8 million decrease in accounts payable and other liabilities and a $4.1 million increase in prepaid expenses and other 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, the timing of vendor invoices and payments and annual bonus payments.

Previous wording

During the nine months ended September 30, 2024, net cash used in investing activities was $188.1 million due to purchases of marketable securities of $264.7 and purchases of property and equipment of $1.3 million, partially offset by maturities of marketable securities of $76.2 million and sales of marketable securities of $1.7 million. During the nine months ended September 30, 2023, net cash provided by investing activities was $57.1 million due to maturities of marketable securities of $100.2 million and sales of marketable securities of $1.8 million, partially offset by purchases of marketable securities of $44.3 million and purchases of property and equipment of $0.6 million.

Current wording

During the three months ended March 31, 2025, net cash provided by investing activities was $1.5 million due to maturities of marketable securities of $65.4 million and sales of marketable securities of $3.0 million, partially offset by purchases of marketable securities of $66.0 and purchases of property and equipment of $1.0 million. During the three months ended March 31, 2024, net cash used in investing activities was $179.8 million due to purchases of marketable securities of $181.4 million and purchases of property and equipment of $0.2 million, partially offset by maturities of marketable securities of $1.7 million.

Previous wording

During the nine months ended September 30, 2024, net cash provided by financing activities was $806.3 million, consisting of $675.2 million in aggregate net proceeds from sales of common stock in our January 2024 and May 2024 offerings, $97.9 million in aggregate net proceeds from sales of common stock under our at-the-market offering program and $33.2 million in proceeds received from stock option exercises. During the nine months ended September 30, 2023, net cash provided by financing activities was $54.2 million, consisting of $52.4 million in aggregate net proceeds from sales of common stock under our at-the-market offering program and $1.8 million in net proceeds received from stock option exercises.

Current wording

During the three months ended March 31, 2025, net cash provided by financing activities was $141.2 million, consisting of $140.6 million in aggregate net proceeds from sales of common stock under our at-the-market offering program and $0.6 million in proceeds received from stock option exercises. During the three months ended March 31, 2024, net cash provided by financing activities was $408.4 million, consisting of $323.9 million in aggregate net proceeds from sales in our public offering in January 2024, $73.6 million in aggregate net proceeds from sales of our common stock under our at-the-market offering program and $10.9 million in net proceeds received from stock option exercises.

Previous wording

We expect our expenses to increase in connection with our ongoing activities, particularly as we advance the clinical development of DYNE-101 and DYNE-251, the development of our FSHD program and additional research programs. The timing and amount of our operating expenditures will depend largely on:

Current wording

We expect our expenses to increase in connection with our ongoing activities, particularly as we advance the clinical development of DYNE-101 and DYNE-251, the development of our FSHD and Pompe programs and additional research programs. The timing and amount of our operating expenditures will depend largely on:

Previous wording

the identification of additional research programs and product candidates;

Current wording

the identification of additional product candidates;

Previous wording

On July 18, 2024, we entered into a letter agreement with a CMO which secures the CMO’s commitment of its manufacturing facilities to manufacture certain of our product candidates and components thereof. The letter agreement obligates us to compensate the CMO at least $54 million for producing certain of our product candidates and components thereof through 2026.

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. The agreement obligates us to compensate the CMO at least $60 million for producing certain of our product candidates and components thereof through 2026. 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

We define our critical accounting policies as those accounting principles generally accepted in the United States of America that require us to make subjective estimates and judgments about matters that are uncertain and are likely to have a material impact on our financial condition and results of operations as well as the specific manner in which we apply those principles. Management has determined that our most critical accounting policies are those relating to accrued research and development expenses and stock-based compensation. As we advance our product candidates into and through clinical development, we expect research and development expenses and, in particular, our accounting for accrued research and development expenses to be an increasingly important critical accounting policy.

Current wording

We define our critical accounting policies as those accounting principles generally accepted in the United States of America that require us to make subjective estimates and judgments about matters that are uncertain and are likely to have a material impact on our financial condition and results of operations as well as the specific manner in which we apply those principles. Management has determined that our most critical accounting policies are those relating to accrued research and development expenses and stock-based compensation and that these policies have the most significant level of estimation uncertainty and have and are reasonably likely to have a material impact on our financial condition and results of operations. As we advance our product candidates into and through clinical development, we expect research and development expenses and, in particular, our accounting for accrued research and development expenses to be an increasingly important critical accounting policy.