A long-term follow-up study to obtain safety and efficacy data in subjects who completed phase 1/2a clinical trial of NEUROSTEM® (NCT02054208), comparing NEUROSTEM and placebo groups for up to 36 months after the initial administration in patients suffering from Alzheimer's disease

The subjects will be followed up at 12-month, 24-month, and 36-month (phone call) after the initial administration of NEUROSTEM®.

Inclusion Criteria:

• Assessment of safety and exploratory treatment efficacy in subjects who were enrolled and completed phase 1/2a clinical trial of NEUROSTEM®.
• Subjects who have been treated with either NEUROSTEM® or placebo at least 12 months ago.
• Subjects who voluntarily decided to participate and signed the consent form after receiving explanations on the clinical trial (in case it is difficult for the participant to sign, the consent of the legal representative)

Exclusion Criteria:

• Subjects who were not enrolled in phase 1/2a clinical trial of Neurostem® for assessing safety and exploratory treatment efficacy
• Other subjects, excluding those listed above, who were deemed unsuitable by the PI