Inclusion Criteria:
* Male or female subjects aged ≥ 50 years at the time of providing informed consent.
* Diagnosis of AD based on the National Institute on Ageing and the Alzheimer's Association criteria, supported by the presence of a Core 1 AD biomarker, specifically elevated plasma ptau217.
* MMSE score between 10 and 26, inclusive, at baseline, corresponding to mild to moderate AD.
* Subjects may be either treatment-naïve or currently receiving stable symptomatic treatment for AD for at least the 2 months prior to screening, including AChEIs, memantine, or a combination of both.
* Subjects must have a designated study partner who provides ongoing support during the study and interacts with the subject for a minimum of 8 hours per week, and will accompany the subject to study visits or be available by telephone at designated times. A second study partner may serve as backup. If the original study partner withdraws from participation, a replacement study partner may be permitted at the investigator's discretion. The replacement study partner must provide informed consent prior to their first study visit with the subject.
* Both the subject (or their legally authorized representative) and the study partner(s) must be capable of providing informed consent.
* Subjects must have adequate literacy, vision, and hearing, in the opinion of the investigator at the time of screening, to allow for valid administration of the clinical outcome assessments.
Exclusion Criteria:
* Presence of any neurological disorder contributing to cognitive impairment other than AD, including but not limited to: Parkinson's disease, Dementia with Lewy bodies, and epilepsy or recurrent seizures.
* Evidence of other clinically significant cerebrovascular disease or intracranial abnormalities based on the latest brain CT or MRI, including but not limited to: multiple lacunar infarcts, large territorial infarcts, severe small vessel or white matter disease, normal pressure hydrocephalus, space occupying lesions.
The most recent available scan (obtained at diagnosis or subsequently) is usually sufficient for screening eligibility to exclude these other conditions. Repeat imaging may need in some cases to be considered if there is clinically significant deterioration or new neurological signs suggestive of a cerebrovascular event.
* Presence of any serious or unstable medical illnesses, including but not limited to: cardiovascular, respiratory, gastroenterological, endocrinologic, immunologic, hematologic, hepatic, or renal and other conditions, that, in the investigator's judgment, may interfere with study participation or compromise subject safety.
* Patients with a CDR Global Score of 0, 0.5 or 3 at the Screening Phase, corresponding to no, very mild or severe dementia, respectively, will be excluded from the study.
* Severe visual or hearing impairment that would prevent the subject from accurately completing clinical outcome assessments.
* Serum creatinine \> 130 µmol/L at baseline, which may affect plasma biomarker analysis.
* Female subjects who are pregnant at screening.
* Participation in another clinical trial or receipt of any investigational product within 60 days or 5 half-lives (whichever is longer) prior to screening.
* Current use at baseline of any AD disease-modifying therapies or neuroprotective/nootropic agents, including Ginkgo biloba, Neurotain, Citicoline, Cerebrolysin, or Piracetam.
* Known hypersensitivity or allergic reaction to MLC901 or any of its components. Any known food allergy or hypersensitivity to Astragalus membranaceus, Ligusticum chuanxiong, Polygala tenuifolia, Angelica sinensis or members of the Fabaceae/Leguminosae family (e.g., legume, pea, bean), Polygalaceae family (e.g., milkwort, snakeroot), Apiaceae/Umbelliferae family (e.g., anise, caraway, carrot, celery, dill, parsley, parsnip) or Quillaja bark (soapbark).
