When three patients die after taking a cutting-edge drug, most companies hit the brakes. Not Sarepta Therapeutics. The Massachusetts-based biotech company is under fire for refusing a request from the U.

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

The company had previously halted shipments to certain older patients following the deaths of two teenagers treated with the therapy, Elevidys.