This study aims to investigate the effects of SHR-1222 on vascular inflammatory factors in patients with low bone mass.

In this study, total 50 patients with low bone mass will be enrolled and divided into 5 dose groups. In the lowest dose group 6 subjects will be recruited, among whom 4 will receive SHR-1222 and the other 2 will receive placebo. In each of the other 4 groups, 11 subjects will be recruited, among whom 9 will be administered with SHR-1222 and the other 2 with placebo.

Levels of nitric oxide (NO), Endothelin-1 (ET-1), plasminogen activator inhibitor-1 (PAI-1) and hypersensitivity C-reactive protein (hs-CRP) will be detected in patients before and after the SHR-1222 injection.

Inclusion Criteria:

• Signed informed consent;
• Male or postmenopausal female;
• Age ≥45 and ≤59 years old;
• The body mass index (BMI) ≥18.5kg/m2 and ≤28 kg/m2;
• T value of areal bone mineral density on any lumbar spine (L1-L4) or collum femoris>-2.5 and <-1;
• The comprehensive physical examination is eligible or slightly abnormal but the researchers determine no clinical implication;
• No smoking, alcohol or drugs abuse.

Exclusion Criteria:

• Any disease affecting bone metabolism;
• Past medical history of cerebral infarction or cerebral arterial thrombosis;
• Past medical history of myocardial infarction;
• Administration of the following drugs within 6m: Hormone replacement therapy, Calcitonin Parathyroid hormone (or any derivative), Supplemental Vitamin D>1,000 IU/day, Glucocorticosteroids (inhaled or topical corticosteroids administered more than 2 weeks before the enrollment date are allowed), Anabolic steroids, Calcitriol and available analogues, thiazide diuretics;
• Administration of the following drugs within 12m: Bisphosphonates, Fluoride for osteoporosis;
• A bone fracture within the previous 6 months;
• A lumbar spine L1-L4 or femoral neck T-score ≤-2.5;
• Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) or gamma pancreatic acyl transferase (GGT) or total bilirubin, more than 1.5 x ULN during screening;
• 3 months prior to screening involved in any drug clinical subjects;
• Subjects determined by the researchers have any food, dietary supplement or drugs that affect SHR-1222 absorption, distribution, metabolism and excretion in 4 weeks prior to screening or within 5 half-lives;
• Serious infection, trauma or major surgery in 4 weeks prior to screening;
• A surgery plan during the study;
• Blood donation and transfusion in 3 months prior to screening;
• Unstable thyroid dysfunction in 6 months prior to screening;
• Human immunodeficiency virus antibody (HIV-ab), syphilis serological examination, hepatitis b virus surface antigen (HBsAg), hepatitis c virus antibody (HCV-ab) were positive;
• Intolerant to venous blood collection;
• A clinical history of drug allergy or a history of atopic allergic diseases (asthma, urticaria, eczema dermatitis) or a known allergy to experimental or similar；
• Subjects with any other situation should not be involved, which determined by the researchers.