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sylvant

Sylvant (Siltuximab) is a medication used to treat Castleman Disease.

Siltuximab · by Recordati Rare Diseases, Inc.

Not yet rated· sourced from the FDA label
Rated against independent regulatory sources·Last updated June 7, 2026·How we rate
Verified againstopenFDANIH DailyMedRxClass

Key facts

Active ingredient
Siltuximab
Form
Injectable
Strength
Siltuximab 100MG · Siltuximab 400MG
Type
Prescription (Rx)
Brand or generic
Brand-name
FDA application
BLA125496

What is Sylvant?

From the FDA label:Siltuximab is a human-mouse chimeric monoclonal antibody that binds human interleukin-6 (IL-6) and is produced by Chinese hamster ovary cells. SYLVANT (siltuximab) for injection is supplied as a sterile, white, preservative free, lyophilized powder in single-dose vials. Each SYLVANT 100 mg single-dose vial contains 100 mg siltuximab, 3.7 mg L-histidine (from L-histidine and L-histidine monohydrochloride monohydrate), 0.8 mg polysorbate 80, and 169 mg sucrose. Each SYLVANT 400 mg single-dose vial contains 400 mg siltuximab, 14.9 mg L-histidine (from L-histidine and L-histidine monohydrochloride monohydrate), 3.2 mg polysorbate 80, and 677 mg sucrose. Following reconstitution with Sterile Water for Injection, USP (per section 2.2), the resulting pH is approximately 5.2. The resulting solution contains 20 mg/mL siltuximab to be administered by intravenous infusion following dilution [see Dosage and Administration (2.2) ] .

How to use

For intravenous infusion only. Administer as an 11 mg/kg dose given over 1 hour by intravenous infusion every 3 weeks. ( 2 ) 2.1 Recommended Dosage Administer SYLVANT 11 mg/kg over 1 hour as an intravenous infusion every 3 weeks until treatment failure. Perform hematology laboratory tests prior to each dose of SYLVANT therapy for the first 12 months and every 3 dosing cycles thereafter. If treatment criteria outlined in Table 1 are not met, consider delaying treatment with SYLVANT. Do not reduce dose. Table 1: Treatment Criteria Laboratory parameter Requirements before first SYLVANT administration Retreatment criteria Absolute Neutrophil Count ≥1.0 × 10 9 /L ≥1.0 × 10 9 /L Platelet count ≥75 × 10 9 /L ≥50 × 10 9 /L Hemoglobin SYLVANT may increase hemoglobin levels in MCD patients <17 g/dL <17 g/dL Do not administer SYLVANT to patients with severe infections until the infection resolves. Discontinue SYLVANT in patients with severe infusion related reactions, anaphylaxis, severe allergic reactions, or cytokine release syndromes. Do not reinstitute treatment. 2.2 Instructions for Preparation and Administration Use aseptic technique for reconstitution and preparation of dosing solution. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit 1. Calculate the dose (mg), total…

Side effects

The following clinically significant adverse reactions are also discussed in other sections of the labeling: Concurrent active severe infections [see Warnings and Precautions (5.1) ] Infusion-related reactions and hypersensitivity [see Warnings and Precautions (5.3) ] Gastrointestinal perforation [see Warnings and Precautions (5.4) ] The most common adverse reactions (>10% of patients) were rash, pruritus, upper respiratory tract infection, increased weight, and hyperuricemia. To report SUSPECTED ADVERSE REACTIONS, contact Recordati Rare Diseases Inc., at 1-888-575-8344 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. Study 1, in MCD, was an international, multicenter, randomized Phase 2 study of every 3 week infusions comparing SYLVANT and best supportive care (BSC) to placebo and BSC. There were 53 patients randomized to the SYLVANT arm at a dosage of 11 mg/kg and 26 patients randomized to the placebo arm. Of the 26 placebo-treated patients, 13 patients subsequently crossed-over to receive SYLVANT. The median age was 48 years (range 20 to 78), 66% male, 48% Asian, 39% White,…

Warnings

Important safety information

Concurrent Active Severe Infections: Do not administer SYLVANT to patients with severe infections, monitor for infections, institute prompt treatment, and interrupt SYLVANT until resolution of infection. ( 2 , 5.1 ) Vaccinations: Do not administer live vaccines because IL-6 inhibition may interfere with the normal immune response to new antigens. ( 5.2 ) Infusion Related Reactions: Administer SYLVANT in a setting that provides resuscitation equipment, medication, and personnel trained to provide resuscitation. ( 5.3 , 6.1 ) Gastrointestinal (GI) perforation: Promptly evaluate patients presenting with symptoms that may be associated or suggestive of GI perforation. ( 5.4 ) 5.1 Concurrent Active Severe Infections Do not administer SYLVANT to patients with severe infections until the infection resolves. SYLVANT may mask signs and symptoms of acute inflammation including suppression of fever and of acute Phase reactants such as C-reactive protein (CRP). Monitor patients receiving SYLVANT closely for infections. Institute prompt anti-infective therapy and do not administer further SYLVANT until the infection resolves. 5.2 Vaccinations Do not administer live vaccines to patients or infants born to patients receiving SYLVANT because IL-6 inhibition may interfere with the normal immune response to new antigens [see Use in Specific Populations (8.1) ]. 5.3 Infusion Related Reactions and Hypersensitivity SYLVANT may cause infusion related reactions and anaphylaxis. Approximately 945 patients have been treated with SYLVANT in clinical trials. Of these, one patient experienced an anaphylactic reaction. Data from 254 patients treated with SYLVANT monotherapy forms the basis of the safety evaluation of infusion related reactions. Infusion related reactions were reported in 5.1% of these patients. Two (0.8%) were Grade 3 or higher, and 1 (0.4%) was serious; none were fatal. Symptoms of infusion reactions consisted of back pain, chest pain or discomfort, nausea and vomiting, flushing, erythema, and palpitations. In long-term treatment of MCD patients with siltuximab at the recommended dosage of 11 mg/kg every 3 weeks, infusion related reactions or hypersensitivity reactions occurred at a frequency of 6.3% (1.3% for severe reactions). Stop the infusion of SYLVANT if the patient develops signs of anaphylaxis. Discontinue further therapy with SYLVANT. Stop the infusion if the patient develops a mild to moderate infusion reaction. If the reaction resolves, the SYLVANT infusion may be restarted at a lower infusion rate. Consider medication with antihistamines, acetaminophen, and corticosteroids. Discontinue SYLVANT if the patient does not tolerate the infusion following these interventions [see Adverse Reactions (6) ]. Administer SYLVANT in a setting that provides resuscitation equipment, medication, and personnel trained to provide resuscitation. 5.4 Gastrointestinal Perforation Gastrointestinal (GI) perforation has been reported in clinical trials although not in MCD trials. Use with caution in patients who may be at increased risk for GI perforation. Promptly evaluate patients presenting with symptoms that may be associated or suggestive of GI perforation.

Who should not take Sylvant

Severe hypersensitivity reaction to siltuximab or any of the excipients in SYLVANT [see Warnings and Precautions (5.3) ] . Hypersensitivity reactions, including anaphylactic reaction, hypersensitivity, and drug hypersensitivity have been reported in patients treated with siltuximab. Severe hypersensitivity reaction to siltuximab or any of the excipients in SYLVANT. ( 4 )

Interactions

7.1 Cytochrome P450 Substrates Cytochrome P450s in the liver are down regulated by infection and inflammation stimuli including cytokines such as IL-6. Inhibition of IL-6 signaling in patients treated with SYLVANT may restore CYP450 activities to higher levels leading to increased metabolism of drugs that are CYP450 substrates compared to metabolism prior to treatment with SYLVANT. Upon initiation or discontinuation of SYLVANT, in patients being treated with CYP450 substrates with a narrow therapeutic index, perform therapeutic monitoring of effect (e.g., warfarin) or drug concentration (e.g., cyclosporine or theophylline) as needed and adjust dose. The effect of SYLVANT on CYP450 enzyme activity can persist for several weeks after stopping therapy. Exercise caution when SYLVANT is co-administered with CYP3A4 substrate drugs where a decrease in effectiveness would be undesirable (e.g., oral contraceptives, lovastatin, atorvastatin).

May treat (source: NIH RxClass)

Dosage forms

Injectable

The forms currently marketed in the U.S., per the FDA National Drug Code Directory.

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Frequently asked questions

What does Sylvant treat?
Sylvant (Siltuximab) may be used to treat castleman disease, based on NIH RxClass drug-classification data (conditions a drug may treat — not a verbatim copy of the FDA-approved label). This is general reference, not medical advice.
Is there a coupon or discount for Sylvant?
pharmaranks is an independent ratings site, not a pharmacy — we don't issue coupons or sell Sylvant. To pay less, ask your prescriber or pharmacist whether a generic equivalent exists, check the manufacturer's copay/savings card and patient-assistance program, and compare a pharmacy discount card against your insurance copay. Prices vary by pharmacy, insurance, and location, so always confirm at the counter. This is general reference, not medical or financial advice.
Who makes Sylvant?
Sylvant is marketed by Recordati Rare Diseases, Inc.. You can see Recordati Rare Diseases, Inc.'s full profile, rating, and other products on pharmaranks.
Is Sylvant a brand-name or generic drug?
Sylvant is a brand-name product with the active ingredient Siltuximab.
Is Sylvant available over the counter?
No. Sylvant is a prescription (Rx) medication in the US — you need a prescription from a licensed clinician (in person or via telehealth); it isn't sold over the counter. For some conditions there are OTC alternatives — ask your pharmacist.
What forms does Sylvant come in?
Sylvant is currently marketed as injectable, per the FDA's National Drug Code Directory.
Is Sylvant FDA-registered?
Sylvant is on record with the U.S. FDA under application number BLA125496. You can verify this on its official FDA label.
Is Sylvant safe?
There's no single safe-or-not verdict, and we don't yet have a composite recall-safety score for Sylvant. Review its FDA-label side effects and warnings below, and always consult a licensed professional.
What are the side effects of Sylvant?
Sylvant's side effects are taken directly from its FDA label. From the label: The following clinically significant adverse reactions are also discussed in other sections of the labeling: Concurrent active severe infections [see Warnings and Precautions (5.1) ] Infusion-related reactions and hypersensitivity [see Warnings and Precautions (5.3) ] Gastrointestinal perforation [s… Both common and serious reactions are documented in full on this page. This is general reference from the FDA, not medical advice — always consult a professional.

Clinical content sourced from the FDA label via openFDA (U.S. FDA). View the FDA label on DailyMed → Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.

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