FDA places clinical hold on Regenxbio's gene therapy for Hunter Syndrome
RGNX•FDA halts RGX-121 after scan abnormalities
Aug. 24 (Reuters) - Regenxbio RGNX.O said on Monday the U.S. FDA has placed its experimental gene therapy for a rare inherited disorder on clinical hold after spinal scans found abnormalities in five study participants, sending its shares down more than 24% in premarket trading.
The therapy, RGX-121, was being developed as a one-time treatment for Hunter Syndrome, also known as MPS II, which can cause progressive damage to the brain and other organs and tissues.
The spinal scans identified a small lump or fluid-filled mass in the patients who received the treatment, RGX-121, about three to six years ago, the biotech said.
Regulatory setback adds to prior approval concerns
The setback adds to Regenxbio's regulatory troubles after the U.S. Food and Drug Administration declined to approve RGX-121 earlier this year over concerns about the trial design and supporting evidence.
RGX-121 was also subject to the health regulator's previous clinical hold on the company's two gene therapy programs.
The therapy uses a harmless virus known as AAV9 vector to deliver the gene needed to produce the missing enzyme in patients with Hunter syndrome.
Current treatment options include Takeda Pharmaceutical's Elaprase, a weekly infusion that treats the physical effects of Hunter syndrome, and Denali Therapeutics' Avlayah, approved in March, to treat neurological symptoms in certain children.
Company says patients were stable and next steps are pending
Regenxbio said the five patients remained asymptomatic and were clinically stable or showed improvements in cognitive and behavioral assessments. Trial investigators deemed the findings to be non-serious and radiologists believed they were likely benign.
