RegenXBio: Clinical Hold on RGX-111/121 Seen as Manageable Timing Issue, Core Gene Therapy Platform and Key Value Drivers Remain Intact Supporting Buy Rating

Stifel Nicolaus analyst Annabel Samimy has reiterated their bullish stance on RGNX stock, giving a Buy rating today.

Annabel Samimy has given his Buy rating due to a combination of factors that mitigate the perceived impact of the recent clinical hold on RGX-111 and RGX-121. He expects a delay to the RGX-121 PDUFA date, but frames it largely as a timing issue given the FDA’s current review backlog and the need to complete additional analyses, rather than a fundamental setback to the program. Samimy underscores that RGX-121 has been produced with RegenXBio’s updated, higher-purity NAVXpress manufacturing process, which distinguishes it from RGX-111 and supports treating the safety event as program-specific rather than platform-wide. He also notes that extensive MRI monitoring of RGX-121 patients to date has not revealed tumor signals, while the strong efficacy in an ultra-rare disease and the known limitations of standard enzyme replacement therapy preserve a favorable risk-benefit profile.
At the platform level, Samimy emphasizes that the main value drivers in his RegenXBio investment thesis—RGX-202 for Duchenne muscular dystrophy and ABBV-RGX-314 for retinal diseases—are largely insulated from the RGX-111 event because they use a different AAV serotype (AAV8), employ the same modern manufacturing platform, and in the case of ABBV-RGX-314, have a large, clean safety database. He highlights that vector integration risk is a recognized, low-frequency feature of AAV gene therapy generally and is already acknowledged in labels such as Zolgensma without evidence of a systemic oncogenic signal. Furthermore, the financial exposure to RGX-121 is limited, as RegenXBio has already monetized the RGX-111/121 royalties and RGX-121 contributes only a small portion of his $45 price target. Given that the core programs and long-term revenue potential remain intact, he views the market’s negative reaction as disproportionate and sees current levels as an attractive entry point, supporting his Buy recommendation.

In another report released today, Clear Street also maintained a Buy rating on the stock with a $50.00 price target.