Sarilumab

• Rheumatoid arthritis (moderate-to-severe)
• Second-line treatment after inadequate DMARD response
• Alternative to TNF inhibitors
• Monotherapy when methotrexate is not tolerated
• Combination therapy with conventional DMARDs

Sarilumab is a fully human monoclonal antibody that blocks interleukin-6 (IL-6) signaling by binding to the IL-6 receptor. It is used to treat moderate-to-severely active rheumatoid arthritis in patients who have had inadequate response to disease-modifying antirheumatic drugs (DMARDs).

How Sarilumab Works

Sarilumab binds to both soluble and membrane-bound IL-6 receptors, preventing IL-6 from transmitting inflammatory signals. IL-6 is a key driver of inflammation and joint destruction in rheumatoid arthritis. By blocking this cytokine pathway, sarilumab reduces synovial inflammation and slows joint damage progression.

Available Formulation

Sarilumab (Kevzara) is available as:

• 150 mg/1.14 mL prefilled syringe
• 200 mg/1.14 mL prefilled syringe
• 150 mg/1.14 mL prefilled pen
• 200 mg/1.14 mL prefilled pen

All formulations are for subcutaneous injection.

Medical Uses

Sarilumab is FDA-approved for adults with moderately-to-severely active rheumatoid arthritis who have had inadequate response or intolerance to one or more DMARDs. It can be used as monotherapy or in combination with methotrexate or other conventional DMARDs.

Dosing Information

The recommended dose is 200 mg subcutaneously every two weeks. Dose reduction to 150 mg every two weeks may be considered for management of neutropenia, thrombocytopenia, or liver enzyme elevations. Some patients may start at 150 mg based on clinical considerations.

Laboratory Monitoring

Regular monitoring is essential due to effects on blood counts and liver function. Check neutrophil count, platelet count, and liver enzymes before starting, 4-8 weeks after initiation, and every 3 months thereafter. Do not start if ANC <2000/mm³ or platelets <150,000/mm³.

Important Safety Information

Sarilumab increases risk of serious infections. Screen for tuberculosis before starting and monitor for infections during treatment. Do not start during active infection. Live vaccines should be avoided. Monitor for GI perforation, especially in patients with history of diverticulitis.

Drug Interactions

IL-6 inhibition can affect CYP450 enzyme activity. When starting or stopping sarilumab, monitor drugs with narrow therapeutic index metabolized by CYP450 enzymes, including warfarin, theophylline, and certain immunosuppressants. Avoid combination with other biologic DMARDs.

Special Populations

Use during pregnancy should weigh benefits against potential risks. Sarilumab may affect infant immune development if used during pregnancy. Women of childbearing potential should use contraception during and for 3 months after treatment. Use caution in patients with hepatic impairment.

Comparison with Other IL-6 Inhibitors

Sarilumab binds the IL-6 receptor like tocilizumab but with potentially higher affinity. Both are effective for rheumatoid arthritis. The choice between them often depends on practical factors including dosing preference, insurance coverage, and individual patient response.

Learn more at MedlinePlus