Design Therapeutics expands at-the-market stock sale program to $200 million

Design Therapeutics, Inc. filed a prospectus supplement dated November 4, 2026 to update an earlier sales agreement prospectus tied to its Form S-3 registration statement. The supplement updates and amends information in a sales agreement prospectus that was originally filed with the SEC earlier in 2025.¹

The arrangement runs through an Open Market Sale Agreement with Jefferies LLC. The company entered into the agreement, dated April 27, 2022, with Jefferies LLC relating to the offer and sale of shares of common stock from time to time through Jefferies acting as agent.¹

Before this filing, the program had a lower cap. Prior to the filing of this prospectus supplement, the sales agreement prospectus covered the offer and sale of up to $100,000,000 of shares of common stock pursuant to the Sale Agreement.¹ As of the date of this prospectus supplement, Design Therapeutics had sold an aggregate of $66,330,496.30 of shares of its common stock pursuant to the sales agreement prospectus.¹

With the new supplement in place, the total authorized amount rises. After giving effect to this prospectus supplement, the company may offer and sell up to $200,000,000 of shares of common stock pursuant to the sales agreement prospectus and this prospectus supplement, inclusive of the $66,330,496.30 already sold.¹

Design Therapeutics' common stock trades on Nasdaq. The stock is listed on the Nasdaq Global Select Market under the symbol "DSGN," and on November 3, 2026, its last reported sale price was $10.34 per share.¹

The filing notes that regulators have not reviewed the offering's accuracy or completeness, a standard disclosure under securities law, and that any claim to the contrary would be a criminal offense. Neither the SEC nor any state securities regulator has passed judgment on whether the sales agreement prospectus and this supplement are truthful or complete, and any statement suggesting otherwise is a criminal offense.¹