Lecanemab for Early-to-Moderate Alzheimer's Disease

Inclusion Criteria: * Age: 50 to 90 years old. * No gender restrictions. * Patients with MCI and mild AD. * The MMSE score is ≥20, and the overall CDR score is 0.5 or 1 point. * Positive Amyloid protein confirmed by amyloid-PET or CSF. * There is a reliable caregiver accompanying the patient during the research visit and supervising the use of the study drug during the trial. * Agree to participate in the research and sign the informed consent form. Exclusion Criteria: * Patients with cognitive impairment caused by reasons other than AD. * There was a history of transient ischemic attack (TIA), stroke, cerebral hemorrhage or epileptic seizure within 12 months prior to screening. * A Hamilton Depression Scale score of more than 17 at the time of screening, or any suicidal behavior within 6 months before screening, during screening, or at baseline visits, as well as other psychiatric diagnoses or symptoms (such as hallucinations, anxiety disorders, or delusions) that interfere with the research process of the subjects. * Patients with hemorrhagic diseases or those receiving anticoagulant therapy, as well as any patients with malignant tumors, severe gastrointestinal, kidney, liver, respiratory, immune, endocrine and cardiovascular system diseases that affect this study. * There is a hypersensitivity reaction to lecanemumab or any other component in the injection solution or any monoclonal antibody treatment. * There are contraindications for MRI scans, including the installation of cardiac pacemakers/defibrillators and ferromagnetic metal implants (except for cranial and cardiac devices approved for safe use in MRI scans). * There is a known or suspected history of drug or alcohol abuse or dependence within two years prior to screening. * Subjects who participated in clinical studies involving any therapeutic monoclonal antibodies or novel compounds for the treatment of AD within 6 months prior to screening, unless it can be demonstrated that the subjects were in the placebo treatment group. * Surgical operations under general anesthesia are planned to be performed during the research period. * Women who have positive pregnancy test results, are breastfeeding or pregnant at the time of screening or baseline.