Siltuximab
Sylvant (siltuximab) is a monoclonal antibody medication used to treat a rare condition called multicentric Castleman disease (MCD). It works by targeting and blocking a specific protein in the body that contributes to abnormal cell growth and inflammation. This prescription medication is administered intravenously by healthcare professionals.
Sylvant is an IL-6 inhibitor monoclonal antibody used to treat multicentric Castleman disease.
Key facts at a glance
- RxNorm
- 1535243
- Generic
- Sylvant
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Sylvant is indicated for the treatment of adult patients with multicentric Castleman disease (MCD) who are HIV-negative and human herpesvirus-8 (HHV-8)-negative. MCD is a rare lymphoproliferative disorder that causes abnormal growth of cells in lymph nodes and can affect multiple organ systems.
Sylvant is a monoclonal antibody that specifically binds to and neutralizes interleukin-6 (IL-6), a signaling protein that plays a key role in immune and inflammatory responses. By blocking IL-6, the medication reduces inflammation and inhibits the abnormal cell growth characteristic of Castleman disease.
Sylvant is administered as an intravenous infusion, typically every 3 weeks. Patients should be monitored for signs of infection during treatment, as immunosuppression may occur. Infusion-related reactions can happen, and live vaccines should be avoided while on therapy. Treatment should be interrupted in patients with severe infections. Regular laboratory monitoring may be required. This medication is not indicated for patients who are HIV or HHV-8 positive.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 9, 2026. · Read our editorial policy