This is a randomized, double-blind, placebo-controlled phase I clinical study to evaluate the safety, tolerability, pharmacokinetics and immunogenicity of single ascending IV doses of CGB3002 in healthy participants. CGB3002 is being developed to treat Alzheimer's Disease.

This study includes 5 planned sequential cohorts. Participants will be randomized to receive a single IV dose of CGB3002, active comparator or placebo, with doses administered in ascending order. Based on the emerging data, there will be options to adjust the number of participants on active or placebo per subsequent dose level, and doses may be repeated or adjusted based on safety, tolerability and plasma pharmacokinetic data. Optional cohorts may be added to evaluate an intermediate dose level or to expand the dose level by SRC.

Inclusion Criteria:

• Must have signed written informed consent before any study-related activities are carried out and must be able to understand the full nature and purpose of the trial, including possible risks and adverse effects. Be willing and able to comply with all study assessments and adhere to the protocol schedule and restrictions.
• Age≥18 years and<55 years at the time of consent, healthy participants, male or female.
• A body mass index (BMI) of 18 to 32 kg/m2 (cutoff inclusive), with male participants weighing no less than 50 kg, female participants weighing no less than 40 kg.
• Males and females of childbearing potential agree to have no plans for childbearing, use reliable contraceptive measures and not to donate sperm or ova from 30 days prior to dosing until 120 days after dosing. For females of childbearing potential, hormonal contraceptives should begin at least 1 month prior to screening to ensure contraceptive is in full effect.

Exclusion Criteria:

• A known history of clinically significant drug allergy or atopic allergic disease (asthma, urticaria, eczematous dermatitis) or a known history of allergy to biologics or any excipients in biologics, fully resolved childhood asthma can be enrolled.
• Any disease that may affect the safety evaluation of the participants or the in vivo process of the investigational product, including the central nervous system, cardiovascular system, digestive system, respiratory system, urinary system, hematopoietic system, metabolic endocrine system, etc.
• Use of prescription drugs within 14 days or five half-lives (whichever is longer) prior study drug administration, unless determined by the Investigator and Sponsor to be non-interfering (e.g., hormonal contraceptives).
• Use of over-the-counter (OTC) or Chinese herbal medicine within 7 days or 5 half-lives (whichever is longer) prior to study drug administration, unless determined by the Investigator and Sponsor to be non-interfering.
• With a history of drug abuse within 12 months prior to dosing.
• Cannot tolerate punction, have a history of needle fainting or blood fainting.
• Have participated in clinical trials, whether for drugs or medical devices, within 30 days prior to administration or within 7 times the known elimination half-life, whichever is longer.
• Blood donation or significant blood loss (> 300 mL) within 30 days prior to dosing, and planning to blood donate during the study.
• Any vaccinations with a live vaccine (excluding influenza vaccine) within 60 days prior to dosing.
• Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) ≥1.5×ULN at screening or Day -2. Total bilirubin (TBIL) > ULN at screening or Day -2(except in those due to findings consistent with Gilbert's disease).
• Estimated creatinine clearance < 80 mL/ min (Cockroft-Gault equation) at screening or Day-2.
• Test positive for syphilis, hepatitis B virus surface antigen (HbsAg), hepatitis B core antibody (HBcAb), hepatitis C virus antibody (HCV-Ab) or HIV antibody at screening.
• Urine drug screening positive at screening or Day-2.
• Have a head MRI demonstrating either cerebral microhemorrhages, or superficial siderosis, or prior evidence of microhemorrhage, or any other major intracranial pathology.
• Still needed or planned to engage in vigorous physical activity or exercise during study participation.
• Other conditions deemed inappropriate by the investigator to participate in the clinical trial.