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Sylvant

siltuximab
Used for Castleman Disease
Used for Castleman Disease

Sylvant (siltuximab) is a preferred infusion treatment for idiopathic multicentric Castleman disease (iMCD). This medication is given once every 3 weeks by a healthcare provider. It's brand only and might be expensive.

Last reviewed on April 21, 2022
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What is Sylvant (siltuximab)?

What is Sylvant (siltuximab) used for?

  • Multicentric Castleman disease (MCD) in people who don't have human immunodeficiency virus (HIV) and human herpesvirus‑8 (HHV‑8), or idiopathic MCD (iMCD)

How Sylvant (siltuximab) works

Sylvant (siltuximab) is an interleukin-6 (IL-6) antagonist. In multicentric Castleman disease (MCD), the body makes too much of a chemical called IL-6. This causes abnormal signaling and inflammation, leading to organ damage and other harmful conditions. Sylvant (siltuximab) binds directly to IL-6 and stops it from interacting with its target receptor on immune cells. It's thought that this helps relieve common symptoms of MCD.

Are you looking for information on Rituxan (rituximab) instead?

Drug Facts

Common BrandsSylvant
Drug ClassInterleukin-6 (IL-6) antagonist
Controlled Substance ClassificationNot a controlled medication
Generic StatusNo lower-cost generic available
AvailabilityPrescription only
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What are the side effects of Sylvant (siltuximab)?

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

  • Skin rash (28%)
  • Itchy skin (28%)
  • Upper respiratory tract infection (e.g., common cold, 26%)
  • Swelling (26%)
  • Weight gain (19%)
  • High uric acid level in the blood (11%)

Other Side Effects

  • Headache
  • Lower respiratory tract infection (e.g., bronchitis, pneumonia)
  • Mouth and throat pain
  • Constipation
  • Kidney damage
  • Low platelet count
  • High triglycerides (fat in the blood)

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following.
  • Severe allergic reaction: trouble breathing, swelling of the lips, tongue, or face, chest tightness, rash
  • Stomach or intestinal damage: sudden, severe pain or tenderness in your stomach

Source: DailyMed

The following side effects have also been reported

Side effects that you should report to your care team as soon as possible:

Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):

pros-and-cons

Pros and cons of Sylvant (siltuximab)

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Pros

First-choice treatment for idiopathic multicentric Castleman disease (iMCD)

Only have to get it once every 3 weeks

Might be able to receive the infusion in your home

Dose can be adjusted based on your weight

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Cons

Must be given by a healthcare provider as an infusion into the veins

Must get regular bloodwork done before and during treatment to make sure Sylvant (siltuximab) is safe for you to receive

Not well studied in people over the age of 65, so it's unknown how well it works for them

Only available as a brand medication, so it can be expensive

pharmacist-tips

Pharmacist tips for Sylvant (siltuximab)

pharmacist
  • Try not to make any other plans for the rest of the day after your first infusion, because you won’t know how your body will react to Sylvant (siltuximab). Your provider will be available to monitor you for any serious reactions.

    • Make sure to tell your provider all of the medications you're taking before starting treatment. Sylvant (siltuximab) can interact with several medications, and your provider might need to adjust your dose accordingly.

      • Mark your next Sylvant (siltuximab) infusion appointment on your calendar so you don't miss it. Even if you start to feel better, treatment typically continues every 3 weeks until your symptoms return. If your symptoms come back, it means the medication might not work as well anymore and your provider will discuss alternative treatment options with you.

        • Remember to get your bloodwork done on time during treatment with Sylvant (siltuximab). For the first year, you'll need to get these blood tests done before each infusion. After this time, you'll need to get these tests done every 3 dosing cycles. Your provider must check your blood counts to make sure Sylvant (siltuximab) is safe for you to receive.

          • Sylvant (siltuximab) can make it harder for you to fight off infections. Tell your healthcare provider right away if you feel sick during treatment so that you can be checked and treated for any infections.

            • Since there's a potential risk of harm to your unborn baby if you receive Sylvant (siltuximab) while pregnant, use birth control during treatment and for 3 months after your last dose. Some forms of birth control might not work as well while you're receiving Sylvant (siltuximab), so ask your provider about birth control that's right for you. If you do become pregnant while receiving this medication, tell your provider.

              • It's not recommended to breastfeed while receiving Sylvant (siltuximab) and for 3 months after your last dose. If you have questions or concerns, speak with your provider.

                faqs

                Frequently asked questions about Sylvant (siltuximab)

                What is multicentric Castleman disease?
                Multicentric Castleman disease (MCD) is a subtype of Castleman disease, a condition where immune cells from the lymph nodes grow quickly. This causes an overgrowth of immune cells that release inflammatory chemicals into your body. The overgrowth of immune cells also causes your lymph nodes to swell. With MCD, these enlarged lymph nodes appear in several areas in the body, and the rapid release of inflammatory chemicals can cause organ failure or other harmful conditions. When the cause of MCD isn't known and people don't have HHV-8 and HIV infection, it's called idiopathic multicentric Castleman disease (iMCD).
                How long does a Sylvant (siltuximab) infusion take?
                Sylvant (siltuximab) is typically infused through your vein over 1 hour. If you experience any infusion-related reactions, your provider might slow down or stop the infusion, which can help, but will make it take longer to complete the treatment dose.
                Can I give Sylvant (siltuximab) to myself?
                No. Sylvant (siltuximab) is given by a healthcare provider at their office or at an infusion center. After the first couple doses, your provider might allow you to continue getting your infusions at home. Talk to your provider to see if it's an option for you to have a nurse administer your infusion at home.
                Does Sylvant (siltuximab) cause weight gain?
                In a clinical study, 19% of participants experienced weight gain during treatment with Sylvant (siltuximab). Talk with your provider if this is a concern for you. They might weigh you periodically, as your dose is based on your body weight.
                Can I receive Sylvant (siltuximab) if I'm pregnant?
                In animal studies, medications like Sylvant (siltuximab) caused harm to pregnant females and their unborn babies. More studies are needed to confirm this risk in pregnant women. But because of this potential risk of harm to the unborn baby, make sure to have a discussion with your provider if you're pregnant or planning to get pregnant during your Sylvant (siltuximab) treatment. It's recommended to avoid becoming pregnant by using birth control during treatment and for 3 months after your last dose.
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                What are the risks and warnings for Sylvant (siltuximab)?

                Sylvant (siltuximab) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

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                Infection risk

                You shouldn't receive Sylvant (siltuximab) if you have a severe infection. This medication can hide signs of an infection (e.g., fever), which can prevent you from getting the proper treatment you might need to get healthy again. Additionally, Sylvant (siltuximab) can make it harder for you to fight off infections. Your provider might have you wait until your infection gets better before giving you Sylvant (siltuximab). Tell your healthcare provider right away if you feel sick anytime during treatment.

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                Avoid live vaccines

                During Sylvant (siltuximab) treatment, you can receive most vaccines, but be sure to avoid any live vaccines. This is because Sylvant (siltuximab) can interfere with your immune system's normal response, so your body might respond to vaccines differently compared to healthy people. Make sure your vaccinations are up to date before starting Sylvant (siltuximab). Tell your provider that you're receiving Sylvant (siltuximab) before you get any vaccines so they can make sure which vaccines are appropriate for you.

                risk-warning

                Infusion-related reactions

                Let your provider know if you start to feel unwell during your Sylvant (siltuximab) infusion. These infusion-related symptoms can include back pain, chest pain or discomfort, nausea and vomiting, flushing, skin redness, and feeling like your heart is racing.

                If any of these reactions occur, your provider might need to adjust how fast you get Sylvant (siltuximab) through your vein (the infusion rate), temporarily stop the infusion, or give you medications (like acetaminophen (Tylenol), antihistamines, or steroids) to manage your symptoms. This might also mean you need to have these medications before your next infusion to prevent or lessen the severity of these symptoms. If you've previously had an infusion-related reaction, your provider may want to observe you for a little while to see how you respond to the infusion in case they need to give you appropriate treatment.

                Rarely, Sylvant (siltuximab) can cause anaphylaxis (closing of the throat). If you experience trouble breathing, swelling of your lips, tongue, or face, chest tightness, or rash after receiving this medication, get medical help right away. If this happens during your infusion, your provider will stop the infusion and you won't receive Sylvant (siltuximab) anymore.

                risk-warning

                Risk of damage in stomach and intestines

                • Risk factors: High risk for a stomach bleed

                  Although rare, Sylvant (siltuximab) can damage your stomach or intestines, which can result in serious bleeds. Let your provider know if you had any recent stomach surgery or have any problems with your gut. You should only use this medication if the benefit is greater than the risk for stomach damage. Call 911 if you get sudden, severe pain or tenderness in your stomach while taking Sylvant (siltuximab), because this could be a sign of stomach or intestinal damage.

                  dosage

                  Sylvant (siltuximab) dosage forms

                  Typical dosing for Sylvant (siltuximab)

                  Sylvant (siltuximab) is only available as an intravenous (IV) infusion that's administered by a healthcare provider. The dose depends on your body weight. In general, the typical dose is 11 mg/kg of body weight given over 1 hour through an infusion into your veins every three weeks.

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