Design Therapeutics surges on positive RESTORE-FA trial data for Friedreich Ataxia lead

Design Therapeutics (NASDAQ:DSGN) announced positive biomarker and clinical findings from its ongoing Phase 1/2 RESTORE-FA clinical trial evaluating DT-216P2 in individuals with Friedreich ataxia (FA).

The data, reflecting a four-week multiple-ascending dose (MAD) intravenous regimen, showed that the therapeutic candidate successfully translated molecular target engagement into measurable, rapid symptomatic relief for patients living with the degenerative genetic disease.

Friedreich ataxia is caused by a GAA repeat expansion mutation in the FXN gene, which severely impairs the transcription of frataxin (FXN)—a vital mitochondrial protein.

DT-216P2, a second-generation GeneTAC® (gene targeted chimera) small molecule, is engineered to bind specifically to this expansion sequence and recruit the cellular machinery required to restore endogenous FXN expression.

The initial 16-patient trial evaluated weekly intravenous infusions across four escalating dose cohorts: 0.1, 0.3, 0.6, and 1 mg/kg (mpk).

In the highest cohort (1 mpk), patients demonstrated profound functional improvements after just four weeks of treatment.

Mean scores on the modified Friedreich's Ataxia Rating Scale (mFARS) improved by 6.4 points from baseline, alongside a 2.7-point improvement in the Upright Stability Score.

Additionally, patient-reported fatigue—assessed via the PROMIS Fatigue Scale—declined by more than 5 points at the end of the treatment window and remained sustained two weeks post-dose.

This drop comfortably cleared the 3-point threshold widely recognized as the minimal important clinical change.

Concurrently, the trial met its key mechanistic objectives, documenting concordant, dose-dependent increases in endogenous frataxin across multiple tissue assays.

In whole blood, treatment yielded a 65% increase in FXN mRNA (p<0.001) and a 22% to 27% increase in mature FXN protein variants (p <0.001).

Crucially, the small molecule demonstrated effective tissue penetration into affected deep systems, generating a 42% increase in FXN mRNA within skeletal muscle biopsies (p= 0.015).

DT-216P2 was generally well-tolerated, with no serious adverse events, dose-limiting toxicities, or treatment discontinuations reported.

The most notable safety findings were mild-to-moderate, transient elevations in alanine transaminase (ALT) in three patients who were also taking background omaveloxolone therapy.