The Food and Drug Administration won’t sign off on Sarepta Therapeutics Inc. bringing its controversial gene therapy back to the market until the company can persuade US regulators that it won’t cause more deaths,

For Sarepta, the hits keep coming, with several downgrades in the past week after it was forced to temporarily take its top-selling drug off the market.

After the FDA request, Cambridge, Massachusetts-based Sarepta said in a statement that it will continue to ship the therapy to ambulatory people but maintain a halt it implemented June 15 for non-ambulatory patients after reporting to the FDA a case of acute liver failure in a patient who could not walk.

Sarepta faces an “arduous and treacherous path” to try to get its Duchenne muscular dystrophy therapy Elevidys back onto the market

Sarepta would need to conduct new analyses to validate the safety of Elevidys—which has had U.S. shipments paused by the company over a mounting string of controversies—to the FDA, Endpoints News reported Thursday, citing an unnamed senior FDA official.

Analysts downgraded Sarepta as FDA pause on Elevidys raises regulatory uncertainty, leading to significant stock pressure and valuation cuts.

Sarepta stock plunged again Thursday on a report that the Food and Drug Administration will require additional clinical testing to validate the safety profile of its controversial gene therapy, Elevidys.

Bank of America downgraded Sarepta Therapeutics (NASDAQ:SRPT) to Underperform from Neutral on Wednesday, becoming the latest brokerage to issue a bearish view on the company, citing safety concerns related to its Elevidys gene therapy marketed with Roche (OTCQX:RHHBY).