REGENXBIO Faces Class Action After FDA Clinical Holds on RGX-111 and RGX-121
A class action lawsuit was filed against REGENXBIO covering the period from February 9, 2022 to January 27, 2026, following FDA clinical holds on gene therapies RGX-111 and RGX-121 after a CNS tumor was discovered in a trial participant.
A class action lawsuit was filed on behalf of investors who purchased or acquired REGENXBIO, Inc. (NASDAQ: RGNX) securities between February 9, 2022 and January 27, 2026. REGENXBIO is a clinical-stage biotechnology company providing gene therapies that deliver functional genes to cells with genetic defects in the United States.
The complaint alleges that defendants continually touted RGX-111 as one of its lead clinical-stage AAV therapeutic product candidate for the treatment of MPS I using its proprietary NAV AAVP vector. Defendants announced in 2018 that RGX-111 had been granted Fast Track designation by the FDA and repeatedly represented that the Phase I/II RGX-111 studies were reporting positive results consistently highlighting "positive interim safety, tolerability, and biomarker data."
The complaint alleges that in truth, defendants were aware of the serious safety issues relating to the RGX-111 study including the potential for CNS neoplasm and in November 2023 abruptly decided to de-prioritize its second-most advanced clinical candidate, RGX-111, and seek "strategic alternatives" for the program.
On January 28, 2026, REGENXBIO issued a press release announcing that the U.S. Food and Drug Administration (FDA) placed a clinical hold on its investigational gene therapy, RGX-111, for the treatment of MPS I, also known as Hurler syndrome, following preliminary analysis of a single case of neoplasm (intraventricular CNS tumor) in a participant treated in its Phase I/II study. The press release also disclosed that the FDA also placed a clinical hold on RGX-121, for the treatment of MPS II, also known as Hunter Syndrome, citing the similarities in products, study populations, and shared risk between the clinical studies.
Following this news, the price of REGENXBIO's common stock declined from a closing market price of $13.41 per share on January 27, 2026 to $11.01 per share on January 28, 2026, a decline of 17.8% in the span of just a single day.
The court-appointed lead plaintiff is the investor with the largest financial interest in the relief sought by the class who is adequate and typical of class members who directs and oversees the litigation on behalf of the putative class. Shareholders who wish to serve as lead plaintiff for the class must submit their papers to the court by April 14, 2026.