Diagnosing a disease that mimics many other conditions

The symptoms of idiopathic multicentric Castleman disease (iMCD) can look like those seen in cancer, autoimmune diseases, and infectious disorders, which can make it challenging to diagnose. After years of research, doctors finally have access to diagnostic guidelines that can help identify this rare disease early so that you or your loved one can receive the right treatment as soon as possible.

Let’s start by helping you understand iMCD, its subtypes, how it differs from other conditions, and how it affects people regardless of their age, gender, or race.

iMCD can mimic over 15 conditions
Doctor feels the neck of a patient exhibiting iMCD symptoms
Yankee, iMCD patient patient testimonial Sylvant

I had so many symptoms that my doctor said are common with other diseases, including cancer. But he said that I didn’t have cancer, I had iMCD, which is rare but treatable.

– Yankee, iMCD patient

iMCD is a subtype of Castleman disease

Castleman disease (CD) is a rare condition that affects the immune system and is characterized by multiple swollen lymph nodes. Bone marrow normally creates immune cells that help our bodies fight infections. In CD, there is an abnormal overgrowth of these cells, causing lymph nodes to swell and resemble a tumor. Groups of swollen lymph nodes may be found in different parts of the body, but these growths are not cancerous.

There are 2 main types of Castleman disease:

Unicentric Castleman disease (UCD)

UCD involves a single group of lymph nodes and can be treated by surgically removing the swollen lymph nodes.

Multicentric Castleman disease (MCD)

MCD affects multiple groups of lymph nodes and can be treated with the help of a targeted therapy.

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There are two subtypes of MCD:

Human herpesvirus-8 (HHV-8)–positive MCD: This can cause Kaposi’s sarcoma—a rare cancer in which lesions grow on the skin, mouth, nose, throat, and other parts of the body.

iMCD: Idiopathic means the cause or origin of the disease is unknown. People with iMCD are human immunodeficiency virus (HIV) negative and HHV-8 negative.

Facts about iMCD

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  • iMCD is estimated to be the most common form of CD, affecting approximately 60% of patients
  • 1000 to 1100 patients in the United States are diagnosed with new cases of iMCD every year
  • iMCD can affect a person regardless of their age, gender, or race
Close-up of interleukin-6 cytokine, the elevation of which can lead to iMCD symptoms.

Interleukin-6 may be elevated during iMCD flare-ups

iMCD is linked to an elevation of one cytokine called interleukin-6 (IL-6).The cause of this overproduction is unknown, but IL-6 may be elevated during flare-ups, and can lead to symptoms of iMCD such as fever, night sweats, and unexplained weight loss.

It is believed that IL-6 is a common disease driver and may be associated with the intensity of symptoms of iMCD.

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Important Safety Information

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

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.

Who should not take SYLVANT?

Do not take SYLVANT if you have had a severe allergic reaction to siltuximab or any of the ingredients in SYLVANT. See the Patient Information for a complete list of ingredients in SYLVANT.

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
  • 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 doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Before you take SYLVANT, tell your healthcare provider about all of your medical conditions, including if you:

  • have an infection. You should not take 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 any pain or discomfort in your stomach.
  • 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 prescription and over-the-counter medicines, vitamins, and herbal supplements.

Please see full Prescribing Information for additional Important Safety Information.