Sarepta Posts Striking siRNA Data for FSHD and DM1, Signaling a Pivot After a Brutal 2025

By FieldPulse Editorial · March 25, 2026

Tags: Clinical Trials, Pipeline

Sarepta Therapeutics released early human data showing a 90-93% reduction in disease-linked gene expression from a single dose of its FSHD drug candidate — a dramatic turn for a company that endured patient deaths and mass layoffs in 2025.

Sarepta Therapeutics is trying to write a new chapter.

On March 25, the company released the first human clinical data from two siRNA programs — SRP-1001 for facioscapulohumeral muscular dystrophy type 1 (FSHD1) and SRP-1003 for myotonic dystrophy type 1 (DM1) — and the early numbers were striking enough to send the stock up more than 20 percent.

For SRP-1001, a single dose produced a 90 to 93 percent reduction in expression of the genes abnormally activated in FSHD1.

The data also showed favorable tolerability and dose-dependent muscle exposure, two critical early signals that a drug is behaving as designed in the target tissue.

SRP-1003 data were also disclosed as part of the readout.

Both programs are currently in Phase 1/2 trials, and Sarepta said it expects to initiate registrational trials for both by the end of 2026.

The context matters enormously here.

Sarepta's 2025 was one of the most turbulent years any mid-sized biotech has endured in recent memory.

The company faced patient deaths linked to its gene therapy programs and responded with a reduction in force of more than 33 percent of its workforce.

The combination of safety concerns and operational contraction raised serious questions about whether Sarepta could rebuild investor and clinical community confidence.

These siRNA results are an attempt to answer those questions.

The mechanism is fundamentally different from gene therapy — siRNA works by silencing specific messenger RNA transcripts, a more targeted and reversible approach that carries a different risk profile.

FSHD and DM1 are both devastating progressive muscle diseases with no approved disease-modifying treatments, making them high-value targets for any developer who can demonstrate clinical proof of concept.

For reps in the rare disease or neuromuscular space — or those watching the broader muscle disease landscape — Sarepta's trajectory is worth monitoring closely.

The company's commercial infrastructure and relationships with neuromuscular.

Source: https://www.statnews.com/2026/03/25/sarepta-therapeutics-fshd-dm1-study-results/