Inclusion Criteria: - Must have completed study CN012-0026, CN012-0027 or CN012-0056. - Subject was aged 55 to 90 years, inclusive, at the time of enrollment into the parent CN012-0026, CN012-0027 or CN012-0056 study. - Can understand the nature of the study and protocol requirements and provide a signed informed consent or, if deemed not competent to provide informed consent, the subject's legally acceptable representative must provide informed consent, and the subject must provide informed assent before any study assessments are performed. - At entry into this study, or any time during the study, if a subject needs to relocate from home or residential assisted-living facility to a nursing home facility, the Sponsor/Medical Monitor must approve the subject's participation in the study. - Have an identified or proxy caregiver (spends approximately 10 hours/week with the subject). Exclusion Criteria: - Significant or severe medical conditions that, in the opinion of the Investigator, could jeopardize the safety of the subject, ability to complete or comply with the study procedures or validity of the study results. - Clinically significant abnormalities, including any finding(s) from the ECG, laboratory tests, physical examination, or vital signs, at the EOT visit of Study CN012-0026, CN012-0027 or CN012-0056 that the Investigator, in consultation with the Medical Monitor, are considered to jeopardize the safety of the subject. - Subjects participating in another investigational drug or device study or planning on participating in another clinical study during the duration of CN012-0028. - Other protocol-defined Inclusion/Exclusion criteria apply.