FILE PHOTO: Signage is seen outside of the Food and Drug Administration (FDA) headquarters in White Oak, Maryland, U.S., August 29, 2020. REUTERS/Andrew Kelly/File Photo

(Reuters) -The U.S. health regulator has allowed a study of Rocket Pharmaceuticals' gene therapy to resume, less than three months after halting it following a patient's death.

The drugmaker's shares soared over 30% in morning trading on Wednesday.

Rocket's mid-stage trial, testing its experimental therapy, RP-A501, for a genetic disorder called Danon disease, was halted in May by the Food and Drug Administration after a patient died from a rare complication.

The company said on Wednesday that the FDA has lifted its clinical hold on the trial, to be resumed with a revised pre-treatment regime and a lower dose of the gene therapy.

Rocket said it will discontinue prophylactic use of drugs that inhibit the C3 protein, which is part of the immune system, as part of the pre-treatment regime.

The patient who died in the May trial was one of two who were administered the C3 inhibitors. The patient had suffered from capillary leak syndrome, which can cause organ failure.

In the new trial, three patients, at least four weeks apart, are expected to receive a lower dose of its therapy. Rocket said the adjusted dose was proposed based on data from an early-stage study, which showed a better safety profile.

Danon disease, which affects males more severely than females, causes heart muscle damage and progressive muscle weakness. Fewer than 1,000 people in the United States are currently known to have the condition, according to National Institutes of Health.

(Reporting by Kamal Choudhury and Padmanabhan Ananthan in Bengaluru; Editing by Sahal Muhammed)