Role of Interleukin 6 Inhibitors in the Management of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a multisystem disease that affects the joints and various organs, resulting in compromised quality of life and increased mortality. A wide spectrum of treatment options is available for RA. Conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) are the first-line of treatment for RA, whereas tumor necrosis factor α inhibitors are commonly used as a second-line biological disease-modifying antirheumatic drug following inadequate response to csDMARDs. However, remission remains difficult to achieve. No single agent is effective for all patients. It is important to consider patients' comorbidities, perspectives, and preferences when selecting treatment.Interleukin 6 (IL-6) plays a prominent role in the pathophysiology of RA and is an important therapeutic target for RA. Tocilizumab and sarilumab are approved IL-6 inhibitors, which have demonstrated good efficacy and tolerability as combination therapy or monotherapy in RA patients with inadequate response to csDMARDs or tumor necrosis factor α inhibitors. Apart from alleviating joint symptoms, inducing remission, and reducing structural damage, tocilizumab and sarilumab exhibit additional advantages in alleviating extra-articular symptoms, such as fatigue and morning stiffness, and have positive effect on anemia and glucose metabolism. Additionally, evidence showed that certain patient subgroups, such as those with comorbidities including anemia and diabetes mellitus, those with early RA, those with high baseline IL-6 levels, those at high risk of tuberculosis infection, or those intolerant to methotrexate monotherapy, may benefit from IL-6 inhibition. Given these advantages, tocilizumab and sarilumab can be considered earlier as a rational choice for treating RA in suitable patients. Future clinical investigations will help refine the use of these agents.