REGENXBIO Inc. (NASDAQ:RGNX) shares are lower during Tuesday's premarket session as the company faces challenges following a recent Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) regarding its Biologics License Application (BLA) for RGX-121, for Mucopolysaccharidosis II (MPS II), an ultra-rare neurodegenerative disease also known as Hunter syndrome.
In May 2025, the FDA accepted the RGX-121 BLA under the accelerated approval pathway; however, the Prescription Drug User Fee Act (PDUFA) goal date was extended from November 9, 2025, to February 8, 2026.
The Catalyst
The FDA issued a CRL for RGX-121, citing concerns about the study eligibility criteria and the appropriateness of a surrogate endpoint for predicting clinical benefit.
The CRL lists several potential paths forward, including a new study, treating additional patients, conducting longer-term follow-up, and using an untreated control arm, all of which would be challenging in an ultra-rare disease population, like MPS II.
REGENXBIO plans to request a Type A meeting to discuss the CRL and aims to resubmit the BLA with additional evidence from global experts to clarify the neuronopathic patient population.
The BLA for RGX-121 for MPS II was supported by positive biomarker, functional, and safety data from the CAMPSIITE I/II/III trial, including out to 12 months.
RGX-121 has been well tolerated in all patients dosed across all phases of the CAMPSIITE trial.
Analyst Take
William Blair notes that rather than safety issues related to the clinical hold, the CRL notes several structural reasons for not approving the gene therapy.
Analyst Myles R. Minter wrote, "While we believe the CRL should be considered in the context of the clinical hold on the program and that there is nuance here in clinical trial designs, we acknowledge that the CRL indicates the FDA is clearly being cautious on granting accelerated approvals without placebo-controlled data."
In January, the FDA placed a clinical hold on REGENXBIO's RGX-111 and RGX-121 programs, prompted by a case of neoplasm detected in a participant treated with RGX-111, leading to scrutiny over the safety of both therapies.
Investors should also note, the FDA also extended Denali Therapeutics Inc.'s (NASDAQ:DNLI) review timeline of the BLA, seeking accelerated approval of tividenofusp alfa for MPS II.
Analyst Consensus & Recent Actions
The stock carries a Buy Rating with an average price target of $31.38. Recent analyst moves include:
- Chardan Capital: Buy (Maintains Target to $52.00) (January 29)
- Stifel: Buy (Raises Target to $45.00) (December 19, 2025)
- Leerink Partners: Outperform (Raises Target to $20.00) (December 15, 2025)
Benzinga Edge Rankings
Below is the Benzinga Edge scorecard for REGENXBIO, highlighting its strengths and weaknesses compared to the broader market:
- Momentum: Strong (Score: 82.9) — Stock is outperforming the broader market.
The Verdict: REGENXBIO's Benzinga Edge signal reveals a strong momentum score, indicating that while the stock is facing significant challenges with regulatory approvals, it is still showing resilience in terms of market performance. Investors should remain cautious but may find opportunities if the company can successfully navigate its current hurdles.
RGNX Price Action: Regenxbio shares were down 10.99% at $9.17 during premarket trading on Tuesday, according to Benzinga Pro data.
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