Phase 1/2 Open-Label Dose-Escalation Study to Evaluate Safety of a Single Intravitreal Injection of RTx-021 in Patients With Stargardt Disease

Inclusion Criteria:

• Male and female patients >= 16 years of age

• Able to comply with the study visit schedule and all protocol assessments

• Diagnosis of Stargardt Disease (genetic testing required)

• Study eye and fellow eye Best Corrected Visual Acuity meeting study criteria

• Presence of retinal ganglion cells and/or retinal nerve fiber layer on SpectralDomain Optical Coherence Tomography testing at Screening confirmed by central imagereading center

• Adequate organ function and general good health

Exclusion Criteria:

• Participation in a clinical study (ocular or non-ocular) with an investigationaldrug, agent, or therapy in the past six months

• Concurrent participation in another interventional clinical ocular study

• Prior receipt of any gene therapy (ocular or other), retinal implant, or ocular celltherapy

• Pre-existing eye conditions in either eye that would preclude the planned treatmentor are significant enough to interfere with the interpretation of study endpoints orprocedural complications

• Known steroid responders if their intraocular pressure was not able to be managedeffectively with topical pressure-lowering medications after prior use of steroidmedications

• Complicating systemic diseases including those in which the disease itself, or thetreatment of the disease, can alter ocular and/or central nervous system function (e.g. radiation treatment of the orbit; leukemia with optic nerve involvement)

• Any immunological response dysfunction including, immuno-compromising diseases oruse of immunosuppressive medications, among others

• Cataract or other ocular (including refractive) surgery, intraocular and/orperi-ocular injection in either eye within the prior four months (i.e. 120 days)prior to screening

• Prior vitrectomy or aphakia in the study eye

• Known sensitivity to any component of the study treatment or contraindication tomedications planned for use in the peri-procedural period (e.g. povidone-iodine toprep for intravitreal injection)

• Known contraindication to prophylactic steroid regimen

• Current pregnancy or breastfeeding

• Any other condition that would not allow the patient to complete follow-upexaminations during the study