A Phase I/II Dose-escalating Study of the Safety, Tolerability and Efficacy of KIO-301 Administered Intravitreally to Patients with Retinitis Pigmentosa and Choroideremia (ABACUS)

Inclusion Criteria:

1. Have a clinical diagnosis of retinitis pigmentosa (Cohorts 1 - 3) or choroideremia (Cohort 3 only).

2. Have a visual acuity of:

3. no light perception for Cohort 3 or

4. no light perception or bare light perception for Cohort 1 confirmed with aLogMar >2.9 using the Berkeley Rudimentary Vision Test (BRVT), or

5. count fingers or hand motion for Cohort 2 as confirmed by a LogMar ≤ 2.9 and > 1.6 using the BRVT.

6. Have similar visual acuity in both eyes as defined as a LogMar difference betweeneyes of < 0.05 using the BRVT.

Exclusion Criteria:

1. Have evidence of material/substantial optic nerve disease.

2. Have a history of retinal detachments.

3. Have clinically significant ocular disease (e.g., corneal oedema, uveitis, severekeratoconjunctivitis sicca) which might interfere with the study or clinicallysignificant opacities of the media.

4. Have high intraocular pressure (IOP) >22 mm Hg.

5. Have had a previous intraocular surgery (excluding phakocataract surgery).

6. Have aphakia.