RGX-121 is a gene therapy which is intended to deliver a functional copy of the iduronate-2-sulfatase gene (IDS) to the central nervous system. This study is a safety and efficacy, dose ranging study to determine whether RGX-121 is safe, effective and well-tolerated by patients with MPS II.
Phase 2 trials begin testing efficacy in a larger patient group (100–300). This is often where biotech binary events occur — positive Phase 2 data can significantly advance a company's pipeline narrative, while failures can be terminal for a program.
Phase 3 trials are pivotal studies with large patient populations (hundreds to thousands) designed to prove efficacy and safety for FDA submission. A successful Phase 3 readout is typically the last major hurdle before a New Drug Application (NDA) or BLA filing.
Enrollment is complete. The trial is in its follow-up or data collection phase — a readout may occur on or near the primary completion date.
REGENXBIO Inc (RGNX) is the sponsoring company for this trial. BiotechSign currently grades this company D (42/100) based on composite catalyst signals across its full pipeline. This trial is one data point in that overall catalyst picture.