Heather McKenzie

REGENXBIO was down 22% in premarket trading Monday after the FDA placed a clinical hold on its embattled Hunter syndrome gene therapy—eschewing the biotech’s plans to refile for approval of the asset in the third quarter. The FDA implemented the hold after the discovery of asymptomatic MRI findings in the spines of five participants in the Phase 1/2/3 CAMPSIITE study—the basis of REGENXBIO’s biologics license application (BLA) for RGX-121, which was rejected by the agency in February.

After the PDUFA date for Capricor Therapeutics’ Duchenne muscular dystrophy cell therapy came and went this weekend without any word, the biotech announced a three-month extension granted by the FDA to review additional data supporting a refined indication.

REGENXBIO was down 22% in premarket trading Monday after the FDA placed a clinical hold on its embattled Hunter syndrome gene therapy—eschewing the biotech’s plans to refile for approval of the asset in the third quarter. The FDA implemented the hold after the discovery of asymptomatic MRI findings in the spines of five participants in the Phase 1/2/3 CAMPSIITE study—the basis of REGENXBIO’s biologics license application (BLA) for RGX-121, which was rejected by the agency in February.