REGENXBIO Inc. 8-K

What Happened REGENXBIO Inc. announced on January 28, 2026 (via Form 8-K) that the U.S. Food and Drug Administration informed the company that its Investigational New Drug (IND) applications for RGX-111 and RGX-121 were placed on clinical hold. RGX-111 is being developed for Mucopolysaccharidosis type I (MPS I) in a Phase I/II trial, and RGX-121 is being developed for Mucopolysaccharidosis type II (MPS II) in a Phase I/II/III trial. A press release dated January 28, 2026 was filed as Exhibit 99.1 and is incorporated by reference.

Key Details

• FDA placed the INDs for both RGX-111 (Phase I/II for MPS I) and RGX-121 (Phase I/II/III for MPS II) on clinical hold.
• The company reported the action via a Current Report on Form 8-K filed January 28, 2026 (Exhibit 99.1 contains the press release).
• The 8-K was signed by Patrick J. Christmas II, Executive Vice President, Chief Strategy & Legal Officer.

Why It Matters A clinical hold stops the initiation or continuation of the affected clinical trials until the FDA’s concerns are resolved. For investors, this can delay development timelines, regulatory milestones, and any potential value inflection points tied to these programs. The filing does not state the reason for the holds or a timeline for resolution; investors should watch for company updates and additional FDA communications for next steps.