

Resources
Advocacy Groups
Living with or caring for someone with a rare disease can be challenging
Below are some advocacy groups where you can connect with others who understand what it’s like, build a support system, and stay up to date on the latest developments in the fight against idiopathic multicentric Castleman disease (iMCD).

The Castleman Disease Collaborative Network (CDCN) is a global initiative dedicated to accelerating research and treatment for Castleman disease.
Visit
The National Organization for Rare Disorders (NORD) is a patient advocacy organization dedicated to individuals with rare diseases and the organizations that serve them.
Visit
Global Genes was established to connect, empower, and inspire the rare disease community.
Visit
RareConnect is a place where people with rare diseases can connect with others globally.
VisitFrequently Asked Questions
Find quick answers to some of the most common questions we hear about SYLVANT.
IL-6, interleukin-6; R.A.R.E., Recordati Access, Resources, and Engagement.
What is SYLVANT?
SYLVANT® (siltuximab) is a prescription medicine used to treat people with multicentric Castleman’s disease (MCD) who do not have human immunodeficiency virus (HIV) and human herpesvirus-8 (HHV-8) infection. It is not known if SYLVANT is safe and effective in children.
IMPORTANT SAFETY INFORMATION
Who should not receive SYLVANT?
Do not receive SYLVANT if you have had a severe allergic reaction to siltuximab or any of the ingredients in SYLVANT. See the Patient Information leaflet for SYLVANT for a complete list of ingredients.
Before starting SYLVANT, tell your healthcare provider (HCP) about all of your medical conditions, including if you:
- have an infection. You should not receive SYLVANT if you have a severe infection.
- have had a recent vaccination or are scheduled to receive any vaccinations. You should not receive a live vaccine during your treatment with SYLVANT.
- have or have had any stomach or bowel (intestine) problems, such as diverticulitis or ulcers. Tell your healthcare provider if you have pain in your stomach area.
- are pregnant or plan to become pregnant. It is not known if SYLVANT will harm your unborn baby. You should not become pregnant while receiving treatment with SYLVANT. Females who are able to become pregnant should use effective birth control during treatment with SYLVANT and for 3 months after stopping treatment.
- are breastfeeding or plan to breastfeed. It is not known if SYLVANT passes into your breast milk. You and your healthcare provider should decide if you will take SYLVANT or breastfeed. You should not do both.Tell your healthcare provider about all the medicines you take, including any prescription and over-the-counter medicines, vitamins, and herbal supplements.
What are the possible side effects of SYLVANT?
SYLVANT may cause serious side effects, including:
- Infections. SYLVANT may lower your ability to fight infections. Tell your healthcare provider right away if you have any signs or symptoms of an infection during treatment with SYLVANT.
- Infusion and allergic reactions. If you have an infusion or allergic reaction while receiving SYLVANT, your healthcare provider will stop your infusion and treat your reaction. If you have a severe infusion or allergic reaction, your healthcare provider may stop your treatment completely. Tell your healthcare provider or get medical help right away if you have any of these symptoms during or after your infusion of SYLVANT: back pain, chest pain or tightness, nausea and vomiting, flushing, redness, irregular heart beat (palpitations), trouble breathing, wheezing, dizziness or light-headedness, swelling of the lips, skin rash, headache, or itching.
- The most common side effects of SYLVANT include rash, itching, upper respiratory tract infection, swelling, weight gain, and increased blood level of uric acid.
These are not all the possible side effects of SYLVANT. Call your HCP for medical advice about side effects. You are encouraged to report side effects of prescription drugs to the FDA. Call 1-800-FDA-1088 or visit www.fda.gov/medwatch.
SYLVANT® (siltuximab) for injection, for intravenous use, is available as 100 mg or 400 mg of lyophilized powder in a single-dose vial.
Please see full Prescribing Information, including Patient Information.