Dysregulated secretion of IL-6 plays a pivotal role in the pathogenesis of 
Castleman disease (CD), a rare lymphoproliferative disorder. In contrast to 
unicentric CD for which surgery is considered the treatment of choice, there is 
no standard therapeutic approach for multicentric CD (MCD). Siltuximab (trade 
name: Sylvant, formerly known as CNTO 328) is a chimeric monoclonal antibody 
with high binding affinity for human IL-6. In a recent randomized 
placebo-controlled Phase II trial, subjects with HIV-negative, HHV8-negative MCD 
who received siltuximab demonstrated a significantly higher rate of durable 
tumor and symptomatic response with a tolerable safety profile, leading to its 
approval for the treatment of HIV-negative HHV8-negative MCD by the US FDA and 
the European Commission in April and May 2014, respectively. This article will 
cover the current treatment options of MCD, the drug profile of siltuximab and 
future directions in the management of MCD.