# Siltuximab

Source: https://onco.cc/drugs/siltuximab/  
OnCo record `siltuximab` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Siltuximab (Sylvant) is an antibody that neutralises the inflammatory messenger interleukin-6. It is the only approved treatment for multicentric Castleman disease, a rare lymph node disorder, in people without HIV or HHV-8 infection.

## Summary

Siltuximab was approved by the FDA in April 2014 and by the EU in the same year for multicentric Castleman disease in HIV-negative and HHV-8-negative patients, on a randomised placebo-controlled phase 2 trial of 79 patients in which durable tumour and symptomatic responses occurred only in the siltuximab arm. Castleman disease is a lymphoproliferative disorder rather than a cancer, but it is managed by haematologist-oncologists and the NCI lists siltuximab among cancer drugs. Infusion is every three weeks indefinitely in responders. Because IL-6 blockade suppresses C-reactive protein and fever, infections may be masked; hypertriglyceridaemia and neutropenia occur. Tocilizumab, which blocks the IL-6 receptor, is used in the same disease off label.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-10
- Tags: nci-list
- Brand: Sylvant
- Modality: Monoclonal antibody (anti-IL-6, chimeric IgG1)
- Mechanism: Binds interleukin-6 directly and prevents it engaging soluble and membrane-bound IL-6 receptors, cutting the cytokine drive behind Castleman disease.
- Approvals: US 2014: Multicentric Castleman disease in HIV-negative and HHV-8-negative patients; EU 2014: Multicentric Castleman disease in HIV-negative and HHV-8-negative adults

## Notes

- Multicentric Castleman disease is a lymphoproliferative disorder with no cancer record.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Siltuximab
- US label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=siltuximab
- NCI drug page: https://www.cancer.gov/about-cancer/treatment/drugs/siltuximab
- EPAR: https://www.ema.europa.eu/en/medicines/human/EPAR/sylvant

## Connected records

- drugs: [Tocilizumab](https://onco.cc/drugs/tocilizumab/)
- technologies: [Monoclonal antibodies](https://onco.cc/technologies/monoclonal-antibody/)
- targets: [Interleukin-6 and IL-6 receptor](https://onco.cc/targets/il6/)
- companies: [Johnson & Johnson](https://onco.cc/companies/johnson-johnson/), [Recordati](https://onco.cc/companies/recordati/)
- trials: [A Clinical Trial of MK-1045 in People With B-cell Acute Lymphoblastic Leukemia (MK-1045-005)](https://onco.cc/trials/nct07570173/), [A Study of Melphalan With or Without Siltuximab in People With Multiple Myeloma Having an Autologous Stem Cell Transplant](https://onco.cc/trials/nct06679829/), [Siltuximab to Decrease Symptom Burden After Autologous Stem Cell Transplantation for Patients With Multiple Myeloma and AL Amyloidosis](https://onco.cc/trials/nct03315026/)

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