clemidsogene lanparvovec (RGX-121) - (CAMPSIITE)

Aug. 24, 2026: REGENXBIO (NASDAQ: RGNX) said the FDA placed a clinical hold on RGX-121 (clemidsogene lanparvovec) for MPS II/Hunter syndrome after asymptomatic spine MRI findings were seen in five participants in the CAMPSIITE study, and the company does not expect to resubmit the RGX-121 BLA in the near term.

The findings were detected under expanded MRI monitoring introduced after the RGX-111 clinical hold. Five patients treated via intracisternal or intraventricular RGX-121 about three to six years earlier had either a small nodule or small cystic mass on spine MRI. Investigators considered the findings nonserious, radiologists believe they are likely benign, and no brain nodules or masses were seen. All five participants reportedly remain clinically well with overall stability to improvement on neurocognitive and neurobehavioral assessments. REGENXBIO said there is no clinical or pathological evidence confirming the nature or cause of the spine findings, and patients will continue periodic imaging observation.

The company and partner NS Pharma are evaluating additional imaging and longer-term follow-up data and plan to incorporate FDA feedback, including the full clinical hold letter, into next steps for RGX-121.

Other upcoming catalysts mentioned: planned RGX-202 Duchenne BLA submission this quarter and topline pivotal wet AMD data for surabgene lomparvovec (ABBV-RGX-314) in the fourth quarter.