FDA Halts Regenxbio's RGX-121 Study After 5 Spine MRI Findings, Sending Shares Down 22%
Updated
Updated · Yahoo Finance · Aug 24
FDA Halts Regenxbio's RGX-121 Study After 5 Spine MRI Findings, Sending Shares Down 22%
3 articles · Updated · Yahoo Finance · Aug 24
Summary
Five of 13 patients in Regenxbio's Campsiite study showed unusual spine MRI findings, prompting the FDA to place RGX-121 on clinical hold and stop dosing for new and existing participants.
Three to six years after receiving the Hunter syndrome gene therapy, those patients had small nodules or cyst-like masses but no related symptoms, while investigators called the findings non-serious and radiologists said they were likely benign.
Nearly 22% premarket share losses pushed Regenxbio to more than two-month lows as the company said it no longer expects a near-term resubmission of RGX-121's marketing application after a July FDA meeting had pointed to a third-quarter filing.
Regenxbio and partner NS Pharma are reviewing additional scans and longer-term follow-up data while awaiting the FDA's full hold letter, with the company shifting investor focus to Duchenne and retinal programs that remain on track.
Are viral vectors triggering long-term spinal abnormalities, or is the FDA overreacting to benign growths in rare disease patients?
With a Q3 2026 FDA resubmission looming, will asymptomatic spinal cysts overshadow the cognitive improvements seen in treated Hunter syndrome patients?