A Study to Evaluate Rocatinlimab (AMG 451) in Healthy Chinese Participants

- Participants must be a resident in mainland China, and of Chinese ancestry (participants whose parents within 3 generations are of Chinese ancestry). - Healthy male or female participants, between 18 and 65 years of age (inclusive) at the time of screening. - Body mass index between 18 and 30 kg/m^2 (inclusive) at the time of screening and check-in. - Provide signed informed consent.

- History or evidence, at screening or check-in, of clinically significant disorder, condition, or disease not otherwise excluded that, in the opinion of the investigator (or designee), would pose a risk to participant safety or interfere with the study evaluation, procedures, or completion. - Evidence of any active bacterial, viral, or fungal infection at screening including but not limited to upper or lower respiratory tract infection, conjunctivitis, acute otitis media, gastritis, enteritis, skin infections, infections requiring treatment with systemic therapy (antibiotics, antiviral, antiparasitic, antiprotozoal, or antifungals) for which therapy has not been completed within 4 weeks before enrollment. - Immunocompromised participants at risk for viral reactivation including participants with history of solid organ transplantation, hematopoietic stem cell transplantation, or cellular therapy. - Participants with disrupted skin integrity (apparent burn or dermatitis). - Prior history of autoimmune disease including but not limited to inflammatory bowel disease (e.g., Crohn’s disease or ulcerative colitis), lupus, rheumatoid arthritis, psoriasis/psoriatic arthritis, multiple sclerosis. - Positive hepatitis B surface antigen (HBsAg)/hepatitis B core antibody (HBcAb) or hepatitis C virus antibody and/or positive human immunodeficiency virus test, at screening. Participants whose hepatitis B and C results are compatible with prior immunity (resulting from inoculation) may be included. - Positive T-spot test at screening. - Participants who have received live vaccines within 5 weeks prior to screening, or plan to receive live vaccines within 120 days after administration of an investigational product. - Participants who have received coronavirus disease 2019 vaccine within 30 days prior to check-in, or plan to receive a coronavirus disease 2019 vaccine within 120 days post-dose. - Use of any over-the-counter or prescription medications within 30 days or 5 half-lives (whichever is longer) before check-in. a. Acetaminophen (paracetamol; up to 2 g/day) for analgesia will be allowed. b. Hormone replacement therapy (e.g., estrogen) and hormonal contraceptives will be allowed. - Participant has received a dose of an investigational drug within the past 90 days or 5 half-lives, whichever is longer, prior to check-in. - Have previously completed or withdrawn from this study or any other study investigating rocatinlimab or have previously received the investigational product.