A Study to Evaluate Safety and Pharmacokinetics of ZB002 in Healthy Participants and Participants With Rheumatoid Arthritis

This study tests the safety and how the body processes a new drug called ZB002 — first in healthy volunteers, then in people with rheumatoid arthritis (an autoimmune condition that causes painful joint inflammation). It is an early-phase safety and dosing study. **You may be eligible if...** - For healthy volunteers: you are between 18 and 55 years old, weigh at least 50 kg (men) or 45 kg (women), and have a normal body mass index - For the rheumatoid arthritis group: you have a confirmed diagnosis of RA and meet additional criteria to be confirmed by your doctor - You are in generally good health aside from RA (for the RA group) **You may NOT be eligible if...** - You have significant chronic illnesses (for the healthy volunteer group) - You are outside the specified weight or age range - You have active infections or conditions that make this drug unsafe Talk to your doctor to see if this trial is right for you.