Shares of Sarepta Therapeutics (SRPT) plunged 43.28% in pre-market trading on Monday following the company's announcement of a second patient death due to acute liver failure after receiving its gene therapy treatment, Elevidys. This tragic news has raised serious concerns about the safety of the therapy, which is the only FDA-approved gene therapy for Duchenne muscular dystrophy patients aged four and above.

In response to the incident, Sarepta has taken immediate action by suspending shipments of Elevidys for non-ambulatory patients and pausing a related clinical trial. The company is also working to convene an independent group of experts to consider an enhanced immunosuppression regimen for the therapy. Both reported fatalities occurred in non-ambulatory patients, prompting questions about the treatment's safety profile for this specific group.

The market reaction has been swift and severe, with several analysts downgrading Sarepta's stock. Piper Sandler cut its rating from Overweight to Neutral and slashed its price target from $70.00 to $36.00, while H.C. Wainwright downgraded the stock to Sell from Neutral. This second fatality, coming just three months after the first reported death in March, has significantly impacted investor confidence in Sarepta's gene therapy program and its market position in treating Duchenne muscular dystrophy.