REGENXBIO Faces FDA Setback on RGX-121 Gene Therapy

RegenXBio ( (RGNX) ) has issued an update.

On February 9, 2026, REGENXBIO Inc. reported that the U.S. Food and Drug Administration had issued a Complete Response Letter for its Biologics License Application for RGX-121, a one-time gene therapy for the ultra-rare neurodegenerative disorder Mucopolysaccharidosis II, or Hunter syndrome. The FDA’s February 7, 2026 letter cited concerns over defining the neuronopathic patient population, the comparability of the external natural history control group, and the use of CSF HS D2S6 as a surrogate endpoint for clinical benefit.

The setback halts near-term approval plans for RGX-121 despite a decade of development and positive biomarker, functional, and safety data from the CAMPSIITE I/II/III trial, and it underscores the regulatory challenges of demonstrating efficacy in ultra-rare diseases. REGENXBIO said it will seek a Type A meeting and pursue a path to resubmit the application, as clinicians and patient advocates warned that delays in access to innovative gene therapies could have severe consequences for children with rapidly progressive Hunter syndrome.

The most recent analyst rating on (RGNX) stock is a Hold with a $12.00 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.

The score is weighed down primarily by weak financial performance (ongoing losses, negative cash flow, and higher leverage) and a materially negative corporate event (FDA clinical holds). Technicals are mixed with near-term weakness but some longer-term support, while valuation remains challenging due to negative earnings. The earnings call provides a partial offset via strong cash runway and multiple near-term pipeline catalysts, but regulatory risk remains the dominant concern.

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

More about RegenXBio

REGENXBIO Inc. is a biotechnology company focused on advancing adeno-associated virus (AAV) gene therapies as one-time treatments for rare and retinal diseases. Its late-stage pipeline includes RGX-202 for Duchenne muscular dystrophy, clemidsogene lanparvovec (RGX-121) for MPS II, RGX-111 for MPS I with Nippon Shinyaku, and surabgene lomparvovec (ABBV-RGX-314) for wet AMD and diabetic retinopathy with AbbVie.

The company’s AAV platform underpins both its own programs and licensed products, including Novartis’ Zolgensma, positioning REGENXBIO as a key player in the emerging gene therapy market. Its therapies target serious unmet medical needs in ultra-rare neurodegenerative conditions and prevalent retinal diseases, with multiple regulatory designations that underscore the potential impact on patients and long-term industry adoption.

Average Trading Volume: 815,452

Technical Sentiment Signal: Sell

Current Market Cap: $522.9M

See more data about RGNX stock on TipRanks’ Stock Analysis page.