Safety and Dose Escalation Study of AAV2-hCHM in Subjects With CHM (Choroideremia) Gene Mutations

The primary objective is to evaluate the safety and tolerability of subretinal administration
of AAV2-hCHM, in an inter-subject group dose escalation in individuals with choroideremia,
based on a comprehensive clinical monitoring plan. The secondary objectives are to define the
dose of AAV2-hCHM required to achieve stable, or improved, visual function/functional vision
and to assess development of immune responses to AAV2 and REP-1.

Inclusion Criteria:

- Male at least 18 years of age diagnosed with CHM gene mutation

- Central visual field (VF) < 30° in any of the 24 meridians (using Goldmann perimetry
III4e isopter) in the eye to be injected

- Any evidence of functioning outer retinal cells within the central 10°

Exclusion Criteria:

- Previous history of ocular inflammatory disease (uveitis)

- Prior intraocular surgery within six months

- Participation in a previous gene therapy research trial within one year of enrollment
or participation in any other ocular gene therapy trial

- Participation in a clinical study with an investigational drug in the past six months

- Grossly asymmetrical disease, or other eye morbidity, which may render the
contralateral eye ineffective as a control

- Visual acuity < 20/200 on standard ETDRS testing in the eye to be injected

- Presence of disease which may preclude the subject from participation in this trial

- Use of medications known to be neuroprotective or retino-toxic that could potentially
interfere with the disease process and/or cause ocular adverse events; individuals who
discontinue use of these compounds for 6 months may become eligible

- Identification by the investigator as being unable or unwilling to perform / be
compliant with study procedures.