Design Therapeutics (DSGN) Corporate presentation summary

Platform and pipeline overview

• Developing GeneTACⓇ small molecules to modulate gene transcription for monogenic disorders.

• Advancing four programs: Friedreich Ataxia (FA), Fuchs Endothelial Corneal Dystrophy (FECD), Myotonic Dystrophy Type 1 (DM1), and Huntington's Disease (HD).

• GeneTACⓇ molecules offer broad tissue distribution, overcoming delivery limitations of traditional genomic medicines.

• Three clinical-stage programs (FA, FECD, DM1) active in 2026, with HD in preclinical development.

• Cash position of $219.8M as of December 2025, expected to fund operations into 2029.

Friedreich Ataxia (FA) program (DT-216P2)

• FA caused by GAA repeat expansion in FXN gene, leading to multi-organ dysfunction.

• DT-216P2 aims to restore endogenous frataxin levels, normalizing FXN in patient cells without affecting healthy cells.

• Prior formulation showed dose-dependent FXN mRNA increase in muscle; new DT-216P2 offers improved exposure and tolerability.

• RESTORE-FA MAD trial ongoing; 12-week patient data expected 2H 2026.

• FA market estimated at $7.3B, with significant unmet need despite existing therapies.

Fuchs Endothelial Corneal Dystrophy (FECD) program (DT-168)

• FECD mainly caused by CTG repeat expansion in TCF4 gene, leading to corneal endothelial dysfunction.

• DT-168 eye drops selectively block mutant TCF4 RNA, reducing nuclear foci and improving spliceopathy in patient cells.

• Phase 1 SAD/MAD study showed DT-168 was well-tolerated with no serious or ocular adverse events.

• Phase 2 biomarker trial ongoing, with data expected 2H 2026; RNA biomarkers developed for clinical proof-of-concept.

• Over 1 million TCF4 expansion patients in the US, representing a multi-billion dollar opportunity.