SAR441566 is an experimental medication that works by blocking a specific protein called TNFR1, which is involved in inflammation. It is being studied as a new treatment for rheumatoid arthritis. This medication is taken together with methotrexate to potentially improve its effectiveness in treating joint inflammation and pain.

Methotrexate is a commonly used medication for treating rheumatoid arthritis. It helps reduce inflammation and slow down joint damage by affecting the immune system. It is considered a standard treatment for rheumatoid arthritis and in this study is used in combination with SAR441566.

Rheumatoid Arthritis – A chronic inflammatory condition that primarily affects the joints throughout the body. The disease occurs when the immune system mistakenly attacks the body’s own tissues, particularly the joint linings, causing inflammation, swelling, and pain. Over time, this inflammation can lead to deterioration of joint cartilage and bones, resulting in joint deformity and reduced mobility. The condition typically affects multiple joints symmetrically, meaning the same joints on both sides of the body are affected. Common symptoms include joint stiffness (especially in the morning), swelling, warmth in affected areas, and fatigue. The disease usually develops gradually, starting with smaller joints in the fingers and toes before potentially progressing to larger joints like knees, hips, and shoulders.