Shares of Sarepta Therapeutics declined 17% in early trading on Friday after another patient who had received an experimental gene therapy died, deepening investor concerns over the use of the company's treatments.

The death of a 51-year-old man in the study follows two other deaths of Duchenne patients treated with Sarepta’s marketed gene therapy Elevidys.

The FDA will request Sarepta Therapeutics stop all shipments of Elevidys, its gene therapy for Duchenne muscular dystrophy, following two deaths tied to the product.

On an investor call Friday, analysts grilled the company over its apparent lack of transparency on the matter.

The restructuring enacted by Sarepta Therapeutics is expected to save up to $400 million in annual costs. Read why I'm downgrading SRPT stock from Hold to Sell.

One of biotech’s highest fliers, Sarepta Therapeutics, lost more than a third of its market value on Friday after executives said that one of its experimental gene-replacement therapies was linked to the death of a 51-year-old man last month who received the treatment in a clinical trial.

Sarepta Therapeutics, Inc. (NASDAQ:SRPT), the leader in precision genetic medicine for rare diseases, today issued the following statement:

As mothers of children with this disease, we have wept helplessly in recent months as friends — fellow members of a club we never asked to join — said goodbye to their sons, the babies they once held in their arms, whose dreams they held in their hearts until Duchenne robbed them of working muscles or a healthy future.