Phase 2 Tolerability and Effects of ALK-001 on Stargardt Disease

Simplified Inclusion Criteria:

• Male or female between 8 and 70 years old (inclusive), with any visual acuity

• Has a clinical diagnosis of typical autosomal recessive Stargardt macular dystrophy (STGD1)

• Has provided a genetic report indicating at least two ABCA4 disease-causingmutations. When only one ABCA4 disease-causing mutation is reported, sponsor'spermission will be required.

• At least one eye (called the "primary study eye") must have at least onewell-demarcated area of significantly reduced autofluorescence as imaged by fundusautofluorescence (FAF), have decreased retinal sensitivity as measured bymicroperimetry, or have maculopathy expected to progress over the duration of thestudy

• Primary study eye must have clear ocular media and adequate pupillary dilation,including no allergy to dilating eyedrops, to permit good quality retinal imaging

• Healthy as judged by investigator

• Able and willing to comply with study requirements, restrictions and instructionsand is likely to complete the 24-month study

• Has signed and dated the informed consent forms (or assent where appropriate) toparticipate

• Female of childbearing potential has signed the informed consent about birth defectsor attestation on contraception requirements

Main Exclusion Criteria:

• Has taken disallowed items (supplement containing vitamin A or beta-carotene,liver-based products, or prescription oral retinoid medications) over the past 30days

• Is lactating, pregnant, or has a positive serum or urine pregnancy test at screeningor at randomization

• Has concurrent medical condition or history, which in the opinion of theinvestigator, is likely to prevent compliance with the protocol and/or interferewith absorption of ALK-001 or study procedures

• Has clinically significant abnormal laboratory result(s) at screening

• Has active or historical acute or chronic liver disorder

• Has active or historical ocular disorder in the primary study eye that, in theopinion of the investigator, may confound assessment of the retina morphologicallyor functionally (this could include for example cataract surgery within the past 6months, choroidal neovascularization (CNV), glaucoma, recurring uveitis, diabeticretinopathy, other retinal disease, etc.)

• Has had intraocular surgery or injections in the primary study eye within 90 days ofthe screening visit

• Has a clinically significant abnormal electrocardiogram (ECG), or has a corrected QTinterval (QTc) that is 450 ms or greater