Design Therapeutics Announces First Quarter 2026 Financial Results and Recent Business Updates

Additional Detail Provided for RESTORE-FA (DT-216P2) Trial Design, Dosing and Endpoints

David Shapiro, M.D., Appointed to Board of Directors, Strengthening Clinical and Regulatory Expertise

Cash and Securities of $222.8 Million at Quarter-End Provide Runway to Support Ongoing Clinical Execution

CARLSBAD, Calif., April 28, 2026 — Design Therapeutics, Inc. (Nasdaq: DSGN), a clinical-stage biotechnology company developing treatments for serious degenerative genetic diseases, today reported first quarter 2026 financial results and highlighted business updates and upcoming milestones across its GeneTAC® portfolio.

“The first quarter was marked by continued operational execution across our portfolio as we progress our clinical programs, including our ongoing RESTORE-FA multiple ascending dose trial evaluating DT-216P2,” said Pratik Shah, Ph.D., chairperson and chief executive officer of Design Therapeutics. “DT-216P2 is designed to restore endogenous frataxin, with the potential to address the underlying cause of Friedreich ataxia and deliver a differentiated therapeutic approach. We believe our GeneTAC® platform represents a novel way to modulate gene expression, with the potential to unlock new therapeutic opportunities across a broad range of rare genetic diseases. We are also pleased to welcome David Shapiro, M.D., to our Board, where his experience will support the continued advancement of our clinical programs.”

Corporate Highlights

• Friedreich Ataxia (FA): Design continues to dose FA patients in its RESTORE-FA trial, a Phase 1/2 multiple ascending dose study of DT-216P2 over four- or 12-week treatment periods to evaluate safety, pharmacokinetics and biomarker endpoints assessing changes in endogenous frataxin (FXN) mRNA and protein levels in whole blood and muscle biopsy samples. Exploratory clinical endpoints include the modified Friedreich Ataxia Rating Scale (mFARS), Upright Stability Score, and PROMIS Fatigue Scale.Design anticipates providing an update on the effect of DT-216P2 on endogenous frataxin levels in the second half of 2026.
• Pipeline: Fuchs Endothelial Corneal Dystrophy (FECD): A Phase 2 biomarker trial of DT-168 is ongoing to evaluate safety, tolerability and corneal endothelium biomarkers in FECD patients who are scheduled for corneal transplant surgery, with data anticipated in the second half of 2026.Myotonic Dystrophy Type-1 (DM1): Design expects to begin dosing DM1 patients in its Phase 1 multiple-ascending dose (MAD) trial of DT-818, a GeneTAC® small molecule designed to selectively reduce transcription of the mutant DMPK allele, in the first half of 2026. The study, with results anticipated in 2027, is expected to assess safety and correction of mis-splicing.Huntington’s disease (HD): Design continues to advance preclinical characterization of several candidate molecules for its Huntington’s disease program.
• Board of Directors: In March 2026, Design appointed David Shapiro, M.D., to its board of directors. Dr. Shapiro has extensive biopharmaceutical experience, including serving as Chief Medical Officer and Head of R&D at Intercept Pharmaceuticals, where he advanced therapies through clinical development and regulatory approval, and as a member of multiple boards of directors.

First Quarter 2026 Financial Results

• R&D Expenses: Research and development (R&D) expenses were $14.4 million for the quarter ended March 31, 2026.
• G&A Expenses: General and administrative (G&A) expenses were $5.3 million for the quarter ended March 31, 2026.
• Net Loss: Net loss was $17.6 million for the quarter ended March 31, 2026.
• Cash Position and Operating Runway: Cash, cash equivalents and investment securities were $222.8 million as of March 31, 2026, which the company expects to fund its planned operations into 2029.

About Design Therapeutics

Design Therapeutics is a clinical-stage biotechnology company developing a new class of therapies based on its platform of GeneTAC® gene targeted chimera small molecules. The company’s GeneTAC® molecules are designed to either dial up or dial down the expression of a specific disease-causing gene to address the underlying cause of disease. In addition to its clinical-stage GeneTAC® programs, DT-216P2, in development for patients with Friedreich ataxia, DT-168, for Fuchs endothelial corneal dystrophy, and DT-818, for myotonic dystrophy type-1, the company is advancing a program in Huntington’s disease. Discovery efforts are underway for multiple genomic medicines. For more information, please visit designtx.com.

Contact

Renee Leck, THRUST [email protected]

DESIGN THERAPEUTICS, INC.

CONDENSED STATEMENTS OF OPERATIONS

(in thousands, except share and per share data)

Three Months Ended March 31,

2026

2025

(unaudited)

Operating expenses:

Research and development

$

14,379

$

15,377

General and administrative

5,327

5,041

Total operating expenses

19,706

20,418

Loss from operations

(19,706

)

(20,418

)

Other income, net

2,070

2,703

Net loss

$

(17,636

)

$

(17,715

)

Net loss per share, basic and diluted

$

(0.29

)

$

(0.31

)

Weighted-average shares of common stock outstanding, basic and diluted

61,434,457

56,757,827

DESIGN THERAPEUTICS, INC.

CONDENSED BALANCE SHEETS

(in thousands)

March 31,

December 31,

2026

2025

(unaudited)

Assets

Current assets:

Cash, cash equivalents and investment securities

$

222,823

$

219,845

Prepaid expenses and other current assets

4,226

3,939

Total current assets

227,049

223,784

Property and equipment, net

824

981

Right-of-use asset

2,569

1,438

Total assets

$

230,442

$

226,203

Liabilities and Stockholders’ Equity

Current liabilities:

Accounts payable

$

2,276

$

2,312

Accrued expenses and other current liabilities

7,914

10,743

Total current liabilities

10,190

13,055

Operating lease liability

2,198

645

Total liabilities

12,388

13,700

Total stockholders’ equity

218,054

212,503

Total liabilities and stockholders’ equity

$

230,442

$

226,203