Efficacy and Safety of DMB-I (INN: Latrepirdine) in Patients With Alzheimer Type Dementia

Inclusion Criteria: * Inclusion Criteria (Group 1 and Group 2): 1. Informed consent to participate in the study. 2. Patients of any gender aged 60 to 90 years inclusive. 3. Patients diagnosed with mild to moderate Alzheimer type dementia according to the NINCDS-ADRDA criteria, receiving basic treatment with memantine at a daily dose of 20 mg for at least 2 months. 4. The MMSE score is in the range of 10-23 inclusive. 5. The ADAS-Cog score is in the range of 20-54 inclusive. 6. No signs of dementia of vascular origin according to CT/MRI data. Repeated Acute Cerebrovascular Accidents (focal infarctions) in brain areas that are critical for cognitive functions and behavior are the mandatory neuroimaging signs of vascular dementia. 7. The Modified Hachinski Ischemic Scale (HIS) score is \< 7. 8. The presence of a caregiver who is in contact with the patient a significant part of the time, agrees to accompany the patient to all visits, monitor the intake of the study drug and fill out the patient's diary. 9. An ability to comply with all Protocol requirements. * Inclusion Criteria (Group 3): 1. Informed consent to participate in the study. 2. Patients of any gender aged 60 to 90 years inclusive. 3. Patients diagnosed with mild to moderate Alzheimer type dementia according to the NINCDS-ADRDA criteria, who are not receiving dementia-contolling medications (memantine, donepezil, rivastigmine, or galantamine) at screening or for the last two (or more) months prior to screening; however, taking such medications for more than two months prior to screening does not limit a patient's participation in the study. 4. The MMSE score is in the range of 10-23 inclusive. 5. The ADAS-Cog score is in the range of 20-54 inclusive. 6. No signs of dementia of vascular origin according to CT/MRI data. Repeated Acute Cerebrovascular Accidents (focal infarctions) in brain areas that are critical for cognitive functions and behavior are the mandatory neuroimaging signs of vascular dementia. 7. The Modified Hachinski Ischemic Scale (HIS) score is \< 7. 8. The presence of a caregiver who is in contact with the patient a significant part of the time, agrees to accompany the patient to all visits, monitor the intake of the study drug and fill out the patient's diary. 9. An ability to comply with all Protocol requirements. Exclusion Criteria: 1. Patients diagnosed with other diseases that cause dementia (severe hypothyroidism, anemia, brain tumor, neuroinfections, etc.) at screening. 2. History of other neurodegenerative diseases of the brain, Parkinson's disease, multiple sclerosis, demyelinating diseases of the nervous system, hereditary degenerative diseases of the central nervous system, abnormalities of the nervous system, uncontrolled epilepsy, hallucinations, other neurological disorders seriously affecting motor or cognitive function, in the opinion of the investigator. 3. History of intolerance to any of the components of the study drug. 4. History of stroke. 5. Active oncological process. 6. The need for surgeries on the vessels of the neck or brain, including endovascular interventions, during the study. 7. Signs of significant uncontrolled concomitant disease that, in the opinion of the Investigator, could prevent the patient from participating in the study, including: * Respiratory system disorders; * Cardiovascular system disorders; * Severe renal impairment (glomerular filtration rate \<30ml/min); * Severe liver dysfunction (ALT, AST \> 2 times the upper limit of normal); * Endocrine system disorders; * Gastrointestinal disorders. 8. Systemic autoimmune diseases or vascular collagenoses requiring previous or current treatment with systemic drugs. 9. Myocardial infarction within 12 months prior to screening. 10. Known systemic infection (viral hepatitis, HIV, tuberculosis, syphilis). 11. Life expectancy less than a year after randomization. 12. Use of drugs that negatively affect cognitive function (tricyclic antidepressants, benzodiazepines, antipsychotics, hypnotics, etc.), as well as drugs of prohibited therapy (including Cerebrolysin, preparations of ginkgo biloba extract, any other drugs with nootropic, antioxidant, metabolic effects, as well as drugs used to treat dementia) within 1 month prior to screening. 13. Moderate to severe depression (Hamilton scale score of 18 or more). 14. Smoking. 15. Episodes of alcohol or drug abuse within the last 6 months. 16. Inability to comply with study procedures even with the assistance, in the opinion of the investigator. 17. Participation in another clinical trial within the last 6 months. 18. Episodes of other serious or unstable psychiatric conditions that make the patient unsuitable for participation in a clinical study, alter the validity of obtaining an informed consent, or may affect the patient's ability to participate in the trial.