A Study Comparing Two Doses of AGTC-501 in Male Participants With X-linked Retinitis Pigmentosa Caused by RPGR Mutations (DAWN)

Inclusion Criteria: * Be ≥12 years of age * Have one eye previously treated with an AAV vector-based gene therapy designed to provide full-length functioning RPGR protein. * Have a BCVA no better than 78 letters and no worse than 34 letters * Be able to perform all tests of visual and retinal function and structure in both eyes based on the participant's reliability and fixation, per the Investigator's discretion. * Have detectable baseline mean macular sensitivity measured by MAIA microperimetry, as determined by the Investigator and confirmed by the Central Reading Center (CRC). * Have detectable EZ line in the study eye as assessed by SD-OCT and confirmed by the CRC. Exclusion Criteria: * Have other known disease-causing mutations documented in the participant's medical history or identified through a retinal dystrophy gene panel that, in the opinion of the Investigator, would interfere with the potential therapeutic effect of the study agent or the quality of the assessments. * Have pre-existing eye conditions that would preclude the planned surgery, interfere with the interpretation of study endpoints, or increase the risk of surgical complications * Had intraocular surgery within 90 days of study treatment administration. * Have any active ocular/intraocular infection or inflammation * Have a history of steroid-induced raised IOP of \>25 mmHg following corticosteroid exposure, despite topical IOP-lowering pharmacologic therapy.