This is a single dose-escalation phase Ⅰa clinical study to observe the safety and pharmacokinetic profiles of RBD1016 in healthy subjects.

The study consists of screening period (Day -28 to Day -1), treatment period (Day 1 to Day 2), safety assessment period (to Day 29) and safety follow-up period (up to Day 85).

It is a randomized, double-blind, placebo-controlled, single dose-escalation, phase Ia study. The study will enroll 40 healthy subjects, including 5 dose escalation cohorts for dose escalation with 0.3 mg/kg body weight as the starting dose.

After a single-dose injection, there will be a 4-week safety assessment and monitoring phase (Days 1-29). Blood samples for PK analysis will be collected within 60 minutes before dosing, and at 0.25, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 24, 48 and 72 h after dosing, respectively. According to the previous PK results, the subsequent PK blood collection points can be adjusted. Total urine samples will be collected once before dosing and in each of 2 time periods after dosing: 0~8 h and 8~24 h. The total urine output will be recorded, and some urine samples will be collected in each time period to analyze and detect the urine drug concentration.

Subjects will undergo safety follow-up from Day 29 to Day 85.

Inclusion Criteria:

1. Subjects who voluntarily participate in this clinical trial, are able to correctly understand and have signed the informed consent in writing;
2. Male or female volunteers aged between 18 and 45 years (inclusive);
3. Body weight: male ≥ 50 kg, female ≥ 45 kg; Body Mass Index (BMI) of 18-30 kg/m2 (inclusive);
4. Vital signs, physical examination, 12-lead ECG, and clinical laboratory tests results are within normal range or beyond the normal range but are not clinically significant at the discretion of the investigator.
5. Subjects who are able to use effective methods of contraception throughout the study and within 6 months after the last administration of the investigational product (refer to Appendix 3 for details);
6. Subjects who are able to cooperate with the investigator, comply with study requirements and complete the study in accordance with relevant procedures of the protocol.

Exclusion Criteria:

1. Subjects with positive hepatitis B surface antigen (HBsAg), HCV antibody or HIV antibody; or subjects with concomitant drug-induced or autoimmune hepatopathy (e.g. positive antinuclear antibody [ANA])
2. Medical history of organ transplant or malignancy.
3. Subjects with clinically significant allergic disease or allergic predisposition or with clear allergy to this product or its composition.
4. Subjects with a history of any serious clinical disease or with clear circulatory system, endocrine system, central nervous system, cardiovascular system, digestive system, respiratory system, urinary system, blood system, immune system or metabolic disorder, or with other diseases inappropriate for entry into this study (e.g. history of psychosis), which are clinically significant at the discretion of the investigator.
5. Creatinine clearance (Ccr) <60ml/min [calculation formula: Ccr: (140-age)×body weight (kg)/0.818×Scr (μmol/L), female ×0.85].
6. History of immune-mediated disease (such as: primary thrombocytopaenic purpura, systemic lupus erythematosis, rheumatoid arthritis, autoimmune hemolytic anemia, serious psoriasis, or any other autoimmune disease) which is clinically significant at the discretion of the investigator.
7. Subjects with acute infection (e.g. influenza) in recent 2 weeks.
8. Subjects who have participated in another clinical study and have received another investigational drug within 1 months before treatment initiation.
9. Subjects with other factors which are unsuitable for study participation at the discretion of the investigators.

NOTE: additional inclusion/exclusion criteria may apply, per protocol