FDA Halts RegenXBio MPS Gene Therapy Trials

An announcement from RegenXBio ( (RGNX) ) is now available.

On January 28, 2026, REGENXBIO announced that the U.S. Food and Drug Administration placed clinical holds on its investigational gene therapies RGX-111 for MPS I (Hurler syndrome) and RGX-121 for MPS II (Hunter syndrome). The action followed detection of an intraventricular CNS tumor in a five-year-old participant who had received RGX-111 four years earlier; preliminary analysis found an AAV vector genome integration event linked to overexpression of the proto-oncogene PLAG1, though causality has not been established and the child remains asymptomatic with developmental gains. No neoplasms have been seen in nine other RGX-111 recipients or in 32 patients treated with RGX-121, and management publicly questioned the FDA’s decision to halt RGX-121 given its safety record and pivotal-trial efficacy to date. The holds temporarily stall two cornerstone ultra-rare disease programs that target critical unmet neurological needs in MPS I and II, introducing regulatory uncertainty for REGENXBIO’s CNS gene therapy platform while heightening scrutiny of AAV vector integration risks across the gene therapy field.

The most recent analyst rating on (RGNX) stock is a Buy with a $37.00 price target. To see the full list of analyst forecasts on RegenXBio stock, see the RGNX Stock Forecast page.

Spark’s Take on RGNX Stock

According to Spark, TipRanks’ AI Analyst, RGNX is a Neutral.

RegenXBio’s overall score is driven by strong technical momentum and positive earnings call sentiment, offset by financial challenges and valuation concerns. The company’s strategic advancements in clinical trials and financial stability are promising, but profitability and cash flow issues remain significant risks.

To see Spark’s full report on RGNX stock, click here.

More about RegenXBio

REGENXBIO Inc. is a biotechnology company focused on adeno-associated virus (AAV) gene therapies, developing one-time treatments for rare diseases and retinal disorders. Its late-stage pipeline includes RGX-202 for Duchenne muscular dystrophy, NAVSUNLI for MPS II and RGX-111 for MPS I in partnership with Nippon Shinyaku, and surabgene lomparvovec (ABBV-RGX-314) for wet age-related macular degeneration and diabetic retinopathy in collaboration with AbbVie, leveraging an AAV platform that has been used to treat thousands of patients, including those receiving Novartis’ Zolgensma.

Average Trading Volume: 689,179

Technical Sentiment Signal: Hold

Current Market Cap: $701.4M

Learn more about RGNX stock on TipRanks’ Stock Analysis page.