Generic Name: siltuximab
Date of Approval: April 22,2014
Company: Janssen Biotech, Inc.

FDA Approves Janssen’s Sylvant for Rare Castleman’s Disease

The U.S. Food and Drug Administration (FDA) has approved Janssen Biotech’s Sylvant (siltuximab), an orphan drug for patients with multicentric Castleman’s disease (MCD). MCD is a rare disorder resembling cancer of the lymph nodes (lymphoma). Siltuximab is a prescription interleukin-6 (IL-6) antagonist that blocks a protein (human‑mouse chimeric monoclonal antibody) to help slow abnormal growth of immune cells. In clinical trials, a tumor response was seen in roughly one-third of 79 participants treated with siltuximab and best supportive care (BSC); however, no participant treated with placebo and BSC had a tumor response. Sylvant is used in patients who do not have HIV or human herpes virus 8. The FDA approved Sylvant on April 22, 2014.

Generic formulations of siltuximab are not yet available on the U.S. market.

Sylvant is indicated for the treatment of adults with multicentric Castleman’s disease (MCD) who are human immunodeficiency virus (HIV) negative and human herpesvirus-8 (HHV-8) negative. It is not approved for use in children.

Siltuximab Formulations Available in the U.S.

Generic Name Brand Name FDA-Approved Uses Formulations
Siltuximab Sylvant multicentric Castleman’s disease (MCD) 100 and 400 mg lyophilized powder in a single-use vial; given as an IV infusion.

Siltuximab Uses

Multicentric Castleman’s disease (MCD)

Patients with MCD have multiple groups of lymph nodes affected in different anatomical areas, compared to unicentric Castleman disease which is localized in one  group of lymph nodes. The focus of care in patients with MCD is to reduce lymph node growths, and aim for disease remission through a combination of treatments; however, the disease often recurs after going to remission. MCD can also cause internal organs to enlarge, and may be life-threatening. Castleman disease is diagnosed through a biopsy of affected lymph nodes.

Common side effects of MCD include:

  • fever
  • weakness
  • fatigue
  • night sweats
  • weight loss
  • loss of appetite
  • nausea
  • vomiting
  • nerve damage that leads to numbness and weakness

Read More: Simultaneous Applications Submitted to FDA and EMA (European Medicines Agency) for Siltuximab

Siltuximab Dosing for Multicentric Castleman’s Disease

Drug Adult Maintenance Dosage Average Monthly Retail Cost
Siltuximab 11 milligrams per kilogram (mg/kg) is given over 1 hour as an infusion into the vein every 3 weeks. N/A; Patients and providers can contact SylvantOne Support by calling 1-855-299-8844.

Other medications used in the adjunctive treatment of Multicentric Castleman’s Disease include:

Siltuximab may be prescribed for purposes other than those listed in the Patient Information. If you have additional questions, you can ask your healthcare provider or pharmacist for a package insert that is written for healthcare providers.

What information should I tell my doctor or other healthcare provider before receiving treatment with siltuximab?

Before you receive siltuximab, tell your healthcare professional about all of your medical conditions. This includes:

  • if you have an infection.
  • if you have recently been vaccinated or are scheduled for one.
  • have or have had any stomach or bowel (intestine) problems, such as diverticulitis or ulcers, or have stomach pain.
  • are pregnant or plan to become pregnant. It is not known if siltuximab will harm your unborn baby. You should use effective birth control during treatment, and for 3 months after stopping treatment with siltuximab.
  • are breastfeeding or plan to breastfeed. It is not known if siltuximab passes into your breast milk. You should not breastfeed while receiving siltuximab.

Siltuximab Side Effects

Siltuximab common side effects may include:

  • a skin rash
  • itching (pruritus)
  • upper respiratory tract infection, such as a sinus infection
  • weight gain
  • elevated blood levels of uric acid

Read More: See Common and Serious Skin Rashes, Prevention and Treatment

More serious, but often less frequent, siltuximab side effects may include:

  • serious infections
  • infusion reactions while you are receiving the drug in your vein, or allergic reactions. Tell your healthcare provider or get medical help right away if you have any of these symptoms during or after your infusion: difficult breathing, tightness in the chest area, wheezing, feeling dizzy or lightheaded, swelling of the lips or face, or a skin rash.

Read More: Understand the Causes, Symptoms and First Aid for Allergic Reactions

This is not a complete list of all possible side effects. Call your doctor for medical advice about side effects. You can report side effects to FDA by calling 1-800-FDA-1088.

See also: Side effects (in more detail)

Siltuximab Drug Interactions

Tell your healthcare provider about all of the medicines you take, including prescription drugs, over-the-counter (OTC), and herbal or dietary products. Specific drug interactions may occur between siltuximab and the following drugs, but other drug interactions can occur, too.

Read More: Atorvastatin: Are Generic Drugs Worth the Risk?

Are there specific people who should not receive siltuximab? What are the ingredients?

This medicine should not be given if you have had a severe allergic reaction to the active ingredient siltuximab or any of the other active or inactive ingredients.

  • Active ingredient: siltuximab
  • Inactive ingredients: L-histidine and L-histidine monohydrochloride monohydrate, polysorbate 80, and sucrose.

Last updated: 2014-05-01 by Leigh Anderson, PharmD.