Siltuximab

How it works

It binds and neutralises interleukin-6 (IL-6), preventing IL-6 from binding its receptor and interrupting the IL-6-driven inflammatory and proliferative signalling that characterises Castleman disease.

Prescribing in practice

• Do not give to patients with a severe active infection, as IL-6 blockade can mask the usual signs of infection and impair the response to it; defer treatment until the infection has resolved.
• Because it suppresses acute-phase responses, C-reactive protein becomes unreliable as a marker of infection during therapy.
• Administered by intravenous infusion under specialist supervision, with monitoring for infusion-related and hypersensitivity reactions.

Monitoring

Monitor the full blood count, for signs of infection, and clinical disease response, recognising that inflammatory markers such as CRP are blunted during treatment.

Counselling the patient

• Report any signs of infection such as fever, sore throat or cough promptly, as your usual symptoms may be masked.
• Avoid live vaccines while receiving this treatment.
• Attend scheduled infusions and blood tests so your response and safety can be tracked.

Evidence & guidelines

Approval was based on a randomised placebo-controlled trial showing improved durable tumour and symptomatic response in multicentric Castleman disease.