Dyne Therapeutics Announces Expanded Debt Facility of Up To $400 Million with Hercules Capital, Inc.

- Up to $125 million in additional borrowing capacity provides further strategic flexibility -

- $50 million of additional capacity funded at amendment closing -

WALTHAM, Mass., June 17, 2026 (GLOBE NEWSWIRE) --  Dyne Therapeutics, Inc. (NASDAQ:DYN), a clinical-stage company focused on delivering functional improvement for people living with genetically driven neuromuscular diseases, today announced that it has entered into an amendment to its non-dilutive senior secured term loan facility with Hercules Capital, Inc. (NYSE:HTGC), a leader in customized debt financing for companies in the life sciences and technology-related markets. The transaction further strengthens the company's balance sheet as it advances zeleciment rostudirsen (z-rostudirsen, also known as DYNE-251) for exon 51 Duchenne muscular dystrophy (DMD) and zeleciment basivarsen (z-basivarsen, also known as DYNE-101) for myotonic dystrophy type 1 (DM1) through critical clinical and regulatory milestones.

"As we continue to focus on diligent execution against our clinical and regulatory objectives, we are pleased to deepen our partnership with Hercules," said Erick Lucera, chief financial officer of Dyne. "This additional access to capital enhances our financial flexibility as we prepare for two potential U.S. launches in the next two years and continue on our mission to deliver functional improvement for individuals living with rare neuromuscular diseases."

"Hercules is proud to be expanding our support of Dyne as they prepare for the potential approval and commercial launches of z-rostudirsen and z-basivarsen," said R. Bryan Jadot, Senior Managing Director and Group Head at Hercules Capital. "Our increased commitment reflects our strong conviction in Dyne's programs and our unique ability to support innovative life sciences companies at transformative stages of development."

Under the terms of the amendment, $50 million was funded upon execution of the amendment, and an additional term loan tranche for $50 million that can be drawn at Dyne's option subject to the achievement of certain milestones was added to the term loan facility. The final term loan tranche was also increased by $25 million to provide up to an additional $75 million, which may be funded upon request of Dyne and at the discretion of Hercules Capital. Including the $50 million funded upon execution of the amendment, Dyne has borrowed an aggregate of $200 million in loan proceeds in three tranches under the term loan facility and maintains access to up to $200 million in potential future funding under the facility.

About Dyne Therapeutics

Dyne Therapeutics is focused on delivering functional improvement for people living with genetically driven neuromuscular diseases. We are developing therapeutics that target muscle and the central nervous system (CNS) to address the root cause of disease. The company is advancing clinical programs for Duchenne muscular dystrophy (DMD) and myotonic dystrophy type 1 (DM1) as well as preclinical programs for facioscapulohumeral muscular dystrophy (FSHD), Pompe disease and multiple DMD mutations. At Dyne, we are on a mission to deliver functional improvement for individuals, families and communities. Learn more at https://www.dyne-tx.com/, and follow us on X, LinkedIn and Facebook.

About Hercules Capital

Hercules Capital, Inc. (NYSE:HTGC) is the leading and largest specialty finance company focused on providing senior secured venture growth loans to high-growth, innovative venture capital-backed companies in a broad variety of technology and life sciences industries. Since inception (December 2003), Hercules has committed more than $27 billion to over 700 companies and is the lender of choice for entrepreneurs and venture capital firms seeking growth capital financing.

Forward-Looking Statements

This press release contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this press release, including statements regarding Dyne's strategy, future operations, prospects and plans, objectives of management, the ability of Dyne to achieve any of the specified clinical, regulatory or commercial milestones under its loan agreement with Hercules Capital, as amended, the potential of the FORCE platform, the potential of zeleciment rostudirsen (z-rostudirsen, also known as DYNE-251) and zeleciment basivarsen (z-basivarsen, also known as DYNE-101), the anticipated timelines for potential commercial launch of z-rostudirsen and z-basivarsen, the availability of expedited approval pathways for z-rostudirsen and z-basivarsen, expectations regarding the outcome of interactions with regulatory authorities, and the sufficiency of Dyne's cash resources for the period anticipated, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. The words "anticipate," "believe," "continue," "could," "estimate," "expect," "intend," "may," "might," "objective," "ongoing," "plan," "predict," "project," "potential," "should," "will," or "would," or the negative of these terms, or other comparable terminology are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Dyne may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and you should not place undue reliance on these forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in these forward-looking statements as a result of various important factors, including: Dyne's ability to comply with the covenants and other obligations under its loan agreement with Hercules Capital; uncertainties inherent in the identification and development of product candidates, including the initiation and completion of preclinical studies and clinical trials; uncertainties as to the availability and timing of results from preclinical studies and clinical trials; the timing of and Dyne's ability to enroll patients in clinical trials; whether results from preclinical studies and data from clinical trials will be predictive of the final results of the clinical trials or other trials; whether data from clinical trials will support submission for regulatory approvals; uncertainties as to the FDA's and other regulatory authorities' interpretation of the data from Dyne's clinical trials and acceptance of Dyne's clinical programs and as to the regulatory approval process for Dyne's product candidates; whether Dyne's cash resources will be sufficient to fund its foreseeable and unforeseeable operating expenses and capital expenditure requirements; as well as the risks and uncertainties identified in Dyne's filings with the Securities and Exchange Commission (SEC), including the company's most recent Form 10-Q and in subsequent filings Dyne may make with the SEC. In addition, the forward-looking statements included in this press release represent Dyne's views as of the date of this press release. Dyne anticipates that subsequent events and developments will cause its views to change. However, while Dyne may elect to update these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing Dyne's views as of any date subsequent to the date of this press release.

Contacts:

Investors

Mia Tobias

ir@dyne-tx.com

781-317-0353



Media

Stacy Nartker

snartker@dyne-tx.com

781-317-1938