Dyne Therapeutics Announces Proposed Public Offering of Common Stock

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 commenced an underwritten public offering of $300,000,000 of shares of its common stock.

Dyne also intends to grant the underwriters a 30-day option to purchase up to an additional $45,000,000 of shares of its common stock.

All of the shares in the proposed offering are to be sold by Dyne.

Morgan Stanley, Jefferies and Evercore ISI are acting as joint book-running managers for the offering.

LifeSci Capital and Raymond James are also acting as joint book-running managers for the offering.

Jones is acting as lead manager for the offering.

The proposed offering is subject to market and other conditions, and there can be no assurance as to whether or when the offering may be completed, or as to the actual size or terms of the offering.

The proposed offering is being made pursuant to a shelf registration statement on Form S-3 that was previously filed with the Securities and Exchange Commission (“SEC”) on March 5, 2024 and became automatically effective upon filing.

This offering will be made only by means of a prospectus supplement and accompanying prospectus that form a part of the registration statement.

A preliminary prospectus supplement relating to and describing the terms of the offering is expected to be filed with the SEC and, if and when filed, copies of the preliminary prospectus supplement relating to the offering may be obtained for free by visiting the SEC’s website at www.sec.gov.

Copies of the preliminary prospectus supplement and the accompanying prospectus may also be obtained by contacting: Morgan Stanley & Co. LLC, Attention: Prospectus Department, 180 Varick Street, 2nd Floor, New York, NY 10014, or by email at [email protected]; Jefferies LLC, Attention: Equity Syndicate Prospectus Department, 520 Madison Avenue, New York, NY 10022, by telephone at (877) 821-7388, or by email at [email protected] ; Evercore Group L.L.C., Attention: Equity Capital Markets, 55 East 52nd Street, 35th Floor, New York, NY 10055, by telephone at (888) 474-0200, or by email at [email protected] ; LifeSci Capital LLC, Attention: LifeSci Capital LLC, 1700 Broadway, 40th Floor, New York, NY 10019, or by email at [email protected] ; or Raymond James & Associates, Inc., at 880 Carillon Parkway, St. Petersburg, Florida 33716, Attention: Equity Syndicate, by calling toll-free at 1-800-248-8863, or emailing at [email protected].

The final terms of the offering will be disclosed in a final prospectus supplement to be filed with the SEC.

This press release shall not constitute an offer to sell, or a solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

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 myotonic dystrophy type 1 (DM1) and Duchenne muscular dystrophy (DMD), and preclinical programs for facioscapulohumeral muscular dystrophy (FSHD) and Pompe disease.

At Dyne, we are on a mission to deliver functional improvement for individuals, families and communities.