A First-in-human Study of KT501 Administered Subcutaneously to Patients With Rheumatoid Arthritis (RA).

This is a first-in-human study testing the safety of a new injectable drug called KT501 in people with moderate to severe rheumatoid arthritis (RA) — a condition where the immune system attacks the joints, causing pain and swelling. **You may be eligible if...** - You are between 18 and 75 years old - You have had a diagnosis of adult-onset rheumatoid arthritis for at least 6 months - Your RA is moderately to severely active - Previous RA treatments have not worked well enough for you - You test positive for certain RA-related antibodies (RF or ACPA) **You may NOT be eligible if...** - You have very severe functional disability from RA - You have another autoimmune disease in addition to RA - You have an active infection or history of serious recurrent infections - You have had cancer in the past 5 years (or breast cancer in the past 10 years) Talk to your doctor to see if this trial is right for you.