Insurance and Co-pay

The Support You Need to Start SYLVANT

Being diagnosed with idiopathic multicentric Castleman disease (iMCD) may come as a surprise for you or your loved one, and you may not know where to start. Patient Connect can help you begin your treatment journey.

Patient Connect is a service offered by EUSA Pharma to help people who have been prescribed SYLVANT. If your insurance doesn’t cover your medication, we might be able to help. Talk to one of our dedicated associates to see if you qualify for financial assistance. 

Our support team can also set up reminders for your upcoming infusion appointments and a lot more. Visit the Patient Connect website to learn more.

Patient Connect
Graphic of Patient Connect, a service offered by EUSA Pharma to help patients who have been prescribed SYLVANT (siltuximab) to help with their idiopathic multicentric Castleman disease symptoms.
Logo of ACCELERATE, a registry for patients with idiopathic multicentric Castleman disease.

Patient Registry

Enrolling With ACCELERATE

ACCELERATE is a registry created and maintained by the University of Pennsylvania that collects medical data about people suffering from Castleman disease. The information is then shared with researchers and doctors, with the goal of improving treatments and treatment plans. 

The Castleman Disease Collaborative Network (CDCN) is on a mission to help fight Castleman disease, and it can only be achieved with your help.

We hope you’ll consider signing up for the registry and becoming part of this initiative.

Learn More Enroll in ACCELERATE

Advocacy Groups

Advocacy groups for caregivers and patients with idiopathic multicentric Castleman disease.

Castleman Disease Collaborative Network (CDCN) is a global initiative dedicated to accelerating research and treatment for Castleman disease.

Global Genes was established to connect, empower, and inspire the rare disease community.

National Organization for Rare Disorders (NORD) is a patient advocacy organization dedicated to individuals with rare diseases and the organizations that serve them.

RareConnect is a place where rare disease patients can connect with others globally.


Frequently Asked Questions

  • What does idiopathic mean?

    The term idiopathic means that the underlying cause or origin of a disease is unknown.

  • What is Castleman disease?

    Castleman disease (CD) is a rare condition in which cells of the lymph nodes and related tissues grow rapidly but are not cancerous. If left undiagnosed and untreated, it can lead to organ failure or other harmful conditions.

  • What are the 2 main types of Castleman disease?

    Unicentric Castleman disease (UCD): Affects only a single lymph node
    Multicentric Castleman disease (MCD): Affects multiple lymph nodes

  • What is iMCD?

    Idiopathic multicentric Castleman disease (iMCD) is a rare disorder in which the body overproduces various cytokines. Cytokines are powerful molecules that are normally secreted by the cells of the immune system in response to infectious or noninfectious agents.

    If these overabundant cytokines are quickly released into the bloodstream, a cytokine storm can occur, with potentially severe or life-threatening effects. In the case of people with iMCD, the cytokine interleukin-6, or IL-6, may be responsible for the storm.

  • What causes iMCD?

    iMCD is linked to an elevation of cytokines, in particular, IL-6. The source of IL-6 overproduction in iMCD is unknown, and the abnormal signaling can lead to a cytokine storm, which can start to attack the immune system.  

  • What are the common symptoms of iMCD?
    • Swollen lymph nodes
    • Flu-like symptoms - fevers, night sweats, fatigue, loss of appetite, and weight loss
    • Fluid accumulation
    • Abnormal discomfort/tenderness
  • Is iMCD a form of cancer?

    iMCD is not cancer; however, it can mimic the symptoms of many other diseases, including some malignancies (ie, cancer), and can be challenging to diagnose.

  • Are there any treatments or medications for iMCD?

    Siltuximab (SYLVANT®) is recommended by the National Comprehensive Cancer Network® (NCCN®) as the preferred treatment option for iMCD. Siltuximab continues to be the first-line therapy recommended by the Castleman Disease Collaborative Network (CDCN) guidelines. 

    SYLVANT is also the only therapy approved by the US Food and Drug Administration (FDA) for the treatment of people with multicentric Castleman disease (MCD) who have tested negative for human immunodeficiency virus (HIV) and human herpesvirus-8 (HHV-8).

  • What is SYLVANT?

    SYLVANT is the preferred treatment for people with iMCD. It is administered via a 1-hour intravenous (IV) infusion, under the supervision of a healthcare professional at an infusion center.

  • How does SYLVANT work?

    SYLVANT works by blocking IL-6, a molecule found in overabundance in people with iMCD. SYLVANT has been shown to resolve the commonly observed symptoms of iMCD and to reduce lymph node size over time.

  • Is SYLVANT safe?

    Any medication can be associated with side effects, and it can vary from person to person. Here are some of the most common side effects observed in people taking SYLVANT:

    • Swollen lymph nodes
    • Flu-like symptoms
    • Rash
    • Itching
    • Upper respiratory tract infections
    • Swelling or fluid accumulation
    • Elevated blood levels of uric acid
    • Weight gain
    • Abnormal enlargement of organs, such as the liver and spleen

    The efficacy of SYLVANT was tested in a randomized clinical trial—the gold standard of clinical studies. 

  • What if my insurance doesn’t cover SYLVANT?

    To see if you qualify for financial assistance, visit to find out if you’re eligible for co-payment assistance.


Glossary of Terms

glossary icon

The removal and examination of tissue, cells, or fluids from the body.


Powerful molecules that are normally secreted by the cells of the immune system in response to infectious or noninfectious agents.

Cytokine storm:

An overreaction of the body’s immune system in which too many cytokines are released into the bloodstream very quickly, with potentially severe or life-threatening effects.


The underlying cause or origin of a disease is unknown.

Lymph nodes:

Lymph nodes make immune cells that help the body fight infection.

Interleukin-6 (IL-6):

A key signaling molecule that helps to regulate the body’s immune system.


A doctor who evaluates the changes caused by disease in tissues and body fluids and helps reach a diagnosis.

Intravenous (IV) infusion:

Administration of a drug solution into a vein.