Three patient deaths linked to neuromuscular drugs developed by Sarepta Therapeutics (NASDAQ:SRPT) have drawn regulatory scrutiny on the viral vector used in the company’s gene therapy platform technology.

Drugmaker Sarepta Therapeutics says it won’t comply with a request from U.S. regulators to halt all shipments of its gene therapy.

Shipments will halt by close of business Tuesday evening, the company said. Sarepta had initially rejected the agency’s request, which was issued Friday.