Open Label Study of ATH-1017 for Treatment of Mild to Moderate Alzheimer's Disease

Inclusion Criteria:

• Subject has completed the Week 26 visit of either of the two blinded parent studies (ATH-1017-AD-0201 or ATH-1017-AD-0202).

• Reliable and capable support person/caregiver who is willing to acceptresponsibility for supervising the daily treatment or, if required, administeringstudy drug.

• Subject capable of giving signed informed consent, or by a legally acceptablerepresentative.

• Subjects must be in generally good health.

• Male subjects and their partners must agree to continue to use a double-barriermethod of contraception during the study, including the follow-up period, unless thepartner is not of childbearing potential.

Exclusion Criteria:

• Subject has experienced a serious adverse event during the parent study, which couldpresent an increased safety risk during the open label extension.

• New diagnosis of severe major depressive disorder even without psychotic features.

• Any subject with formalized delusions or hallucinations.

• Significant suicide risk.

• Newly-diagnosed malignant tumor, except for the following conditions that are stablein the judgement of the investigator:

• Adequately treated squamous and basal cell carcinoma, or squamous and basalcell carcinoma in situ

• Prostate carcinoma in situ