Mechanism of Action

How SYLVANT® works as an Multicentric Castleman’s Disease treatment by working as an IL-6 Antagonist

SYLVANT® (siltuximab) Mechanism of Action

SYLVANT® (siltuximab) Mechanism of Action

Siltuximab binds human interleukin-6 (IL-6) and prevents the binding of IL-6 to both soluble and membrane-bound IL-6 receptors. IL-6 has been shown to be involved in diverse normal physiologic processes such as induction of immunoglobulin secretion. Overproduction of IL-6 has been linked to systemic manifestations in patients with Multicentric Castleman’s Disease (MCD).

Interleukin-6 (IL-6) is an important driver in the etiology of Multicentric Castleman’s Disease1

  • Clinical evidence suggests that excess IL-6, an inflammatory regulating cytokine, plays an important role in the etiology of MCD.1,2

Limitation of use:

SYLVANT® was not studied in patients with MCD who are HIV positive or HHV-8 positive because SYLVANT® did not bind to virally produced IL-6 in a nonclinical study.3

SYLVANT® (siltuximab) is an IL-6 antagonist

SYLVANT® is a monoclonal antibody that binds to human IL-6. Overproduction of IL-6 has been linked to systemic manifestations in patients with MCD.3

It is indicated for the treatment of patients with MCD who are human immunodeficiency virus (HIV) negative and human herpesvirus-8 (HHV-8) negative.3

To learn more about how SYLVANT® works, please watch this short video


  1. van Rhee F, Stone K, Szmania S, Barlogie B, Singh Z. Castleman disease in the 21st century: an update on diagnosis, assessment, and therapy. Clin Adv Hematol Oncol. 2010;8(7):486-498.
  2. El-Osta HE, Kurzrock R. Castleman’s disease: from basic mechanisms to molecular therapeutics. Oncologist. 2011;16(4):497-511.
  3. SYLVANT® [package insert]. Hertfordshire, UK: EUSA Pharma UK Ltd; June 2019.