Enspryng Satralizumab 120 mg/mL Injection, Solution, 1 syringe
🆔 Identity & classification
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🏷️ RxNorm drug class
This medicine belongs to the Interleukin inhibitors class.
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🏭 Manufacturer & labeler
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🩺 Clinical
Satralizumab-mwge injection is used to treat neuromyelitis optica spectrum disorder (NMOSD; an autoimmune disorder of the nervous system that affects eye nerves and the spinal cord) in certain adults. Satralizumab-mwge is in a class of medications called interleukin-6 (IL-6) receptor inhibitors. It works by blocking the activity of the part of the immune system that may damage certain areas of the nervous system in people with NMOSD.
Read the full MedlinePlus article ↗Patient education
Supplement & herbal interactions
Some supplements/herbs that may interact with Satralizumab — tap one for details:
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🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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26.1 mg / 1 mL
UNII 94ZLA3W45F
Arginine is an amino acid used in medicines as a buffer and pH adjuster. It helps maintain the proper acidity level and stability of liquid formulations.
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UNII 30KYC7MIAI
Aspartic acid is an amino acid used in pharmaceutical formulations as a pH buffer and to help stabilize active ingredients. It works to maintain the proper acidity level in the medicine.
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3.1 mg / 1 mL
UNII 4QD397987E
An amino acid used as a buffer and stabilizer in medications. It helps maintain the pH balance and protects the active drug from breaking down during storage and use.
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0.5 mg / 1 mL
UNII LQA7B6G8JG
A synthetic polymer made by combining water-soluble compounds. It acts as a surfactant and solubilizer to help mix oil and water-based ingredients, improving the medicine's texture and how active ingredients dissolve.
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UNII 059QF0KO0R
Water is a liquid solvent that dissolves and mixes ingredients together in liquid medicines, syrups, and injections. It helps distribute the active drug evenly throughout the product.
5 inactive ingredients listed in the exact product block matched to this NDC.
Where does this data come from?
ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per mL | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | Not in the retail survey — common for institutional, discontinued, or low-volume packs. | |
| Medicaid paysCMS SDUD · 12 mo | $16,787.15 | $16,787.15 / 1 ml |
| Medicare drug plans payPart D · Q2 2026 | $17,541.31 | $17,541.31 / 1 ml |
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Enspryng 120 mg/mLthis 50242-0007-01 | Genentech, | 1 syringe | — | — | FDA listed | — |
Where does this data come from?
⏳ Availability & biosimilar status
Biologics have no small-molecule generics; biosimilar competition is tracked in the FDA Purple Book.
Why the date isn’t exact: Biosimilar timing can change because patents may be challenged, settled, licensed, added or removed, and litigation can move the real date earlier or later.
🛈 What do these terms mean?
- Biologic patent
- A patent the reference product’s maker has publicly listed. A biosimilar generally can’t launch until these expire — unless they’re invalidated or resolved in a settlement.
- Reference-product exclusivity
- A flat 12 years of FDA market protection from the biologic’s first licensure (the BPCIA). No biosimilar can be licensed before it ends, regardless of patents.
- Interchangeable exclusivity
- The first interchangeable biosimilar can earn a period as the only interchangeable version (pharmacists can substitute it without the prescriber).
- Earliest biosimilar (LOE)
- The latest of all the dates above — the soonest a biosimilar can realistically reach the market. Litigation and settlements can move it earlier.
Biologics have no small-molecule “generics” — competition comes from FDA-licensed biosimilars, tracked in the FDA Purple Book.
| Code | What it grants | Expires |
|---|---|---|
| RefProduct | Reference-product exclusivity (12-year, BPCIA) — no biosimilar can be licensed before this date | Aug 14, 2032 |
Is there a biosimilar for ENSPRYNG 120 MG/ML SYRINGE?
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Can a biosimilar launch before the last patent expires?
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What does a patent or protection date mean here?
Where does this data come from?
🗺️ Medicaid utilization & spend
💊 Medicaid utilization by pack size
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
🔬 Reported adverse events (FAERS)
Top reported reactions
Age at onset
Reporter sex
Serious outcomes
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📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 50242-0007-01 You're viewing this | 1 SYRINGE, PLASTIC in 1 CARTON (50242-007-01) / 1 mL in 1 SYRINGE, PLASTIC | 2020-08-14 | Active |
| 50242-0007-86 | 1 SYRINGE, PLASTIC in 1 CARTON (50242-007-86) / 1 mL in 1 SYRINGE, PLASTIC | 2021-08-13 | Active |
| 50242-0007-33 | 1 SYRINGE in 1 CARTON (50242-007-33) / 1 mL in 1 SYRINGE | 2026-06-10 | Active |
| 50242-0007-55 | 1 SYRINGE, PLASTIC in 1 CARTON (50242-007-55) / 1 mL in 1 SYRINGE, PLASTIC | 2026-06-10 | Active |
In Medicaid, this is the most-dispensed pack of this product — about 100% of fills over the last four reported quarters. See all packs ↓
Pack size FAQ
What quantity is in NDC 50242-0007-01?
What is the difference between NDC 50242-0007-01 and NDC 50242-0007-86?
What NDC number is used to bill for this package of Enspryng Satralizumab 120 mg/mL Injection, Solution?
🧭 About this NDC listing & data coverage
What data is (and isn’t) available for this NDC — tap to expand
| NDC identity (package / product / labeler codes) | ✓ Available |
| Labeler | ✓ Available |
| Product & package description | ✓ Available |
| Marketing category & status | ✓ Available |
| Active ingredient / dosage form / route | ✓ Available |
| FDA label (SPL via DailyMed) | ✓ Available |
| Package photos | ✓ Available |
| Inactive ingredients (structured) | ✓ Available |
| NADAC pharmacy acquisition price (CMS) | — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey. |
| Orange Book / therapeutic-equivalence data | ✓ Available |
| HCPCS J-code billing crosswalk | — Not published for this NDC Most self-administered / retail products have no J-code — that is normal. |
| Medicaid utilization (CMS SDUD) | ✓ Available |
Questions about this listing
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📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
1 INDICATIONS AND USAGE ENSPRYNG is indicated for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in adult patients who are anti-aquaporin-4 (AQP4) antibody positive. ENSPRYNG is an interleukin-6 (IL-6) receptor antagonist indicated for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in adult patients who are anti-aquaporin-4 (AQP4) antibody positive. ( 1 )
⏱️ Dosage and Administration ▾
2 DOSAGE AND ADMINISTRATION Hepatitis B virus, tuberculosis, and liver transaminase screening is required before the first dose. ( 2.1 ) Prior to every use, determine if there is an active infection. ( 2.2 ) The recommended loading dosage of ENSPRYNG for the first three administrations is 120 mg by subcutaneous injection at Weeks 0, 2, and 4, followed by a maintenance dosage of 120 mg every 4 weeks.
( 2.2 ) See Full Prescribing Information for important preparation and administration instructions. ( 2.3 )
2.1Assessments Prior to the First Dose of ENSPRYNG Hepatitis B Virus Screening Prior to initiating ENSPRYNG, perform Hepatitis B virus (HBV) screening. ENSPRYNG is contraindicated in patients with active HBV confirmed by positive results for surface antigen [HBsAg] and anti-HBV tests. For patients who are negative for HBsAg and positive for HB core antibody [HBcAb+] or are carriers of HBV [HBsAg+], consult liver disease experts before starting and during treatment with ENSPRYNG [see Contraindications (4) and Warnings and Precautions (5.1) ] .
Tuberculosis Screening Prior to initiating ENSPRYNG, evaluate for active tuberculosis and test for latent infection. For patients with active tuberculosis or positive tuberculosis screening without a history of appropriate treatment, consult infectious disease experts before initiating treatment with ENSPRYNG [see Contraindications (4) and Warnings and Precautions (5.1) ] . Liver Transaminase Screening Liver transaminases and serum bilirubin should be assessed prior to initiation of treatment with ENSPRYNG [see Warnings and Precautions (5.2) ] .
Caution should be exercised when considering initiation of ENSPRYNG treatment in patients whose aspartate aminotransferase (AST) or alanine aminotransferase (ALT) levels are greater than 1.5 times the upper limit of normal (ULN). Vaccinations Because vaccination with live-attenuated or live vaccines is not recommended during treatment with ENSPRYNG, administer all immunizations according to immunization guidelines at least 4 weeks prior to initiation of ENSPRYNG for live or live-attenuated vaccines and, whenever possible, at least 2 weeks prior to initiation of ENSPRYNG for non-live vaccines [see Warnings and Precautions (5.1) ].
2.2Recommended Dosage For subcutaneous use only. Prior to every use of ENSPRYNG, advise patients to consult with their healthcare professional (HCP) if they suspect an active infection, including localized infections. In case of active infection, delay use of ENSPRYNG until the infection is resolved [see Warnings and Precautions (5.1) ] .
The recommended loading dosage of ENSPRYNG for the first three administrations is 120 mg by subcutaneous injection at Weeks 0, 2, and 4, followed by a maintenance dosage of 120 mg every 4 weeks. Missed Dose If a dose of ENSPRYNG is missed for any reason other than increases in liver enzymes [see Dosage and Administration (2.4) ] , administer as described in Table 1 . Table 1 Recommended Dosage for Delayed or Missed Doses Last Dose Administered Recommended Dosage for Delayed or Missed Doses Less than 8 weeks during the maintenance period or missed a loading dose Administer 120 mg by subcutaneous injection as soon as possible, and do not wait until the next planned dose.
Maintenance period After the delayed or missed dose is administered, reset the dose schedule to every 4 weeks. Loading period If the second loading dose is delayed or missed, administer as soon as possible and administer the 3 rd and final loading dose 2 weeks later. If the third loading dose is delayed or missed, administer as soon as possible and administer the 1 st maintenance dose 4 weeks later.
8 weeks to less than 12 weeks 120 mg by subcutaneous injection at 0 "0 weeks" refers to time of the first administration after the missed dose. and 2 weeks, followed by 120 mg every 4 weeks. 12 weeks or longer 120 mg by subcutaneous injection at 0 , 2, and 4 weeks followed by 120 mg every 4 weeks.
2.3 Important Administratio…
💊 Dosage Forms and Strengths ▾
3 DOSAGE FORMS AND STRENGTHS Injection: 120 mg/mL clear, and colorless to slightly yellow solution in single-dose prefilled syringe or single-dose autoinjector. Injection: 120 mg/mL in a single-dose prefilled syringe ( 3 ) Injection: 120 mg/mL in a single-dose prefilled autoinjector ( 3 )
⛔ Contraindications ▾
4 CONTRAINDICATIONS ENSPRYNG is contraindicated in patients with: A known hypersensitivity to satralizumab or any of the inactive ingredients [see Warnings and Precautions (5.4) ] Active Hepatitis B infection [see Warnings and Precautions (5.1) ] Active or untreated latent tuberculosis [see Warnings and Precautions (5.1) ] Known hypersensitivity to satralizumab or any of the inactive ingredients ( 4 ) Active Hepatitis B infection ( 4 ) Active or untreated latent tuberculosis ( 4 )
⚠️ Warnings and Cautions ▾
5 WARNINGS AND PRECAUTIONS Infections: Delay ENSPRYNG administration in patients with an active infection until the infection is resolved. Vaccination with live or live-attenuated vaccines is not recommended during treatment. ( 5.1 ) Elevated Liver Enzymes: Monitor ALT and AST levels during treatment; interruption of ENSPRYNG may be required. ( 5.2 ) Decreased Neutrophil Counts: Monitor neutrophils during treatment. ( 5.3 )
5.1Infections An increased risk of infections, including serious and potentially fatal infections, has been observed in patients treated with IL-6 receptor antagonists, including ENSPRYNG. The most common infections reported in a randomized clinical trial of patients treated with ENSPRYNG who were not on other chronic immunosuppressant therapies (Study 1), and that occurred more often than in patients receiving placebo, were nasopharyngitis (12%) and cellulitis (10%). The most common infections in patients who were on an additional concurrent immunosuppressant, and that occurred more often than in patients receiving placebo, were nasopharyngitis (31%), upper respiratory infection (19%), and pharyngitis (12%).
Delay ENSPRYNG administration in patients with an active infection, including localized infections, until the infection is resolved. Hepatitis B Virus (HBV) Reactivation Risk of HBV reactivation has been observed with other immunosuppressant therapies. Patients with chronic HBV infection were excluded from clinical trials.
Perform HBV screening in all patients before initiation of treatment with ENSPRYNG. Do not administer ENSPRYNG to patients with active hepatitis. For patients who are chronic carriers of HBV [HBsAg+] or are negative for HBsAg and positive for HB core antibody [HBcAb+], consult liver disease experts before starting and during treatment with ENSPRYNG.
Tuberculosis Tuberculosis has occurred in patients treated with other interleukin-6 receptor antagonists. Patients should be evaluated for tuberculosis risk factors and tested for latent infection prior to initiating ENSPRYNG. Consider anti-tuberculosis therapy prior to initiation of ENSPRYNG in patients with a history of latent or active tuberculosis in whom an adequate course of treatment cannot be confirmed, and for patients with a negative test for latent tuberculosis but having risk factors for tuberculosis infection.
Consult infectious disease experts regarding whether initiating anti-tuberculosis therapy is appropriate before starting treatment. Patients should be monitored for the development of symptoms and signs of tuberculosis with ENSPRYNG, even if initial tuberculosis testing is negative. Vaccinations Live or live-attenuated vaccines should not be given concurrently with ENSPRYNG because clinical safety has not been established.
Administer all immunizations according to immunization guidelines at least 4 weeks prior to initiation of ENSPRYNG for live or live-attenuated vaccines and, whenever possible, at least 2 weeks prior to initiation of ENSPRYNG for non-live vaccines.
5.2Elevated Liver Enzymes Mild and moderate elevations of liver enzymes have been observed in patients treated with ENSPRYNG at a higher incidence than in patients receiving placebo [see Adverse Reactions (6.1) ] . ALT and AST levels should be monitored every 4 weeks for the first 3 months of treatment, followed by every 3 months for one year, and thereafter, as clinically indicated [see Dosage and Administration (2.4) ].
5.3Decreased Neutrophil Counts Decreases in neutrophil counts were observed in patients treated with ENSPRYNG at a higher incidence than placebo [see Adverse Reactions (6.1) ]. Neutrophil counts should be monitored 4 to 8 weeks after initiation of therapy, and thereafter at regular clinically determined intervals [see Dosage and Administration (2.4) ].
5.4Hypersensitivity Reactions Hypersensitivity reactions, including rash, urticaria, and fatal anaphylaxis, have occurred with other interleukin-6 receptor antagonists.
🤒 Adverse Reactions ▾
6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Infections [see Warnings and Precautions (5.1) ] Elevated Liver Enzymes [see Warnings and Precautions (5.2) ] Decreased Neutrophil Counts [see Warnings and Precautions (5.3) ] Hypersensitivity Reactions [see Warnings and Precautions (5.4) ] The most common adverse reactions (incidence at least 15%) are nasopharyngitis, headache, upper respiratory tract infection, gastritis, rash, arthralgia, extremity pain, fatigue, and nausea.
( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Genentech at 1-888-835-2555 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
6.1Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in clinical practice. The safety of ENSPRYNG was evaluated in two randomized, placebo-controlled clinical trials [Study 1 evaluated ENSPRYNG without concurrent immunosuppressive therapy (IST) and Study 2 evaluated ENSPRYNG with concurrent IST], which included 41 anti-AQP4 seropositive patients treated with ENSPRYNG in Study 1 and 26 anti-AQP4 seropositive patients treated with ENSPRYNG in Study 2 [see Clinical Studies (14) ] .
In the double-blind, controlled period, the median exposure time on ENSPRYNG treatment was approximately 2 years in Study 1 and approximately 3 years in Study 2. The median exposure time on placebo treatment was approximately 1 year in both Study 1 and Study 2. Adverse reactions that occurred in Study 1 and Study 2 in more than 5% of patients treated with ENSPRYNG, and at a greater incidence than in patients who received placebo, are shown in Table 3 and Table 4 , respectively.
The most common adverse reactions (15% or greater with ENSPRYNG in either) were nasopharyngitis, headache, upper respiratory tract infection, gastritis, rash, arthralgia, extremity pain, fatigue, and nausea. Table 3 Adverse Reactions Occurring in 4 or More Patients Treated with ENSPRYNG and Greater Incidence than Placebo in Study 1 Adverse Reaction ENSPRYNG (N = 41) % PLACEBO (N = 23) % Rash 17 0 Arthralgia 17 0 Pain in extremity 15 9 Fatigue 15 4 Nausea 15 9 Nasopharyngitis 12 4 Pruritus 10 0 Depression 10 0 Cellulitis 10 0 Neutropenia 10 4 Blood creatine phosphokinase increased 10 4 Fall 10 4 Table 4 Adverse Reactions Occurring in 3 or More Patients Treated with ENSPRYNG and Greater Incidence than Placebo in Study 2 Adverse Reaction ENSPRYNG + IST (N = 26) % PLACEBO + IST (N = 26) % Nasopharyngitis 31 15 Headache 27 12 Upper respiratory tract infection 19 12 Gastritis 15 0 Arthralgia 12 0 Pharyngitis 12 8 Injection-Related Reactions In Study 1 and Study 2, injection-related reactions were reported in 9% of patients treated with ENSPRYNG compared with 8% in patients receiving placebo.
These reactions in the ENSPRYNG-treated patients were predominantly mild to moderate in severity, and most occurred within 24 hours after the injection. The most commonly reported systemic symptom was diarrhea. The reported local injection site reactions were pruritus, injection site reaction, and skin mass.
Infections In Study 1, the rate of patients with infections was 51 patients/100 patient-years (95% CI: 32, 78) in patients treated with ENSPRYNG compared with 108 patients/100 patient-years (95% CI: 52, 199) in patients receiving placebo. The rate of patients with serious infections was 5 patients/100 patient-years (95% CI: 1, 14) in patients treated with ENSPRYNG compared with 4 patients/100 patient-years (95% CI: 0, 21) in patients receiving placebo. In Study 2, the rate of patients with infections was 168 patients/100 patient-years (95% CI: 100, 265) in patients treated with ENSPRYNG compared with 143 patients/100 patient-years (95% CI: 83, 229) in patients treated with placebo.
The rate of pati…
👥 Use in Specific Populations ▾
8 USE IN SPECIFIC POPULATIONS
8.1Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ENSPRYNG during pregnancy. Healthcare providers are encouraged to register patients and pregnant women are encouraged to register themselves by calling 1-833-277-9338. Risk Summary There are no adequate data on the developmental risk associated with the use of ENSPRYNG in pregnant women.
In an animal reproduction study, no adverse effects on maternal animals or fetal development were observed in pregnant monkeys and their offspring, with administration of satralizumab-mwge at doses up to 50 mg/kg/week (see Data ) . In the U.S. general population, the estimated background risk of major birth defect and miscarriage in clinically recognized pregnancies is 2 – 4% and 15 – 20%, respectively. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown.
Clinical Considerations Fetal/neonatal adverse reactions Monoclonal antibodies are increasingly transported across the placenta as pregnancy progresses, with the largest amount transferred during the third trimester. Risks and benefits should be considered prior to administering live or live-attenuated vaccines to infants exposed to ENSPRYNG in utero [see Warnings and Precautions (5.1) ] . Data Animal Data Weekly subcutaneous administration of satralizumab-mwge (0, 2, or 50 mg/kg) to monkeys throughout pregnancy resulted in no adverse effects on postnatal development of the offspring; however, immune function was impaired in offspring at both doses.
Plasma exposures (C ave ) in dams at the low and high doses were approximately 3 and 100 times, respectively, that in humans at the recommended monthly maintenance dose of 120 mg.
8.2Lactation Risk Summary No information is available on the presence of satralizumab-mwge in human milk, the effects of the satralizumab-mwge on the breastfed infant, or the effects of the satralizumab-mwge on milk production. Satralizumab-mwge was excreted in the milk of lactating monkeys administered satralizumab-mwge throughout pregnancy. Human IgG is excreted in human milk and the potential for absorption in the infant is unknown.
The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for ENSPRYNG and any potential adverse effects on the breastfed infant from ENSPRYNG or from the underlying maternal condition.
8.4Pediatric Use Safety and effectiveness in pediatric patients have not been established.
8.5Geriatric Use Clinical studies of ENSPRYNG did not include sufficient numbers of patients aged 65 years and older to determine whether they respond differently from younger patients. However, population pharmacokinetic analyses in patients with NMOSD did not show that age affected the pharmacokinetics of satralizumab-mwge [see Clinical Pharmacology (12.3) ] . In general, caution should be used when dosing the elderly, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant diseases or other drug therapy.
🤰 Pregnancy ▾
8.1Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ENSPRYNG during pregnancy. Healthcare providers are encouraged to register patients and pregnant women are encouraged to register themselves by calling 1-833-277-9338. Risk Summary There are no adequate data on the developmental risk associated with the use of ENSPRYNG in pregnant women.
In an animal reproduction study, no adverse effects on maternal animals or fetal development were observed in pregnant monkeys and their offspring, with administration of satralizumab-mwge at doses up to 50 mg/kg/week (see Data ) . In the U.S. general population, the estimated background risk of major birth defect and miscarriage in clinically recognized pregnancies is 2 – 4% and 15 – 20%, respectively. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown.
Clinical Considerations Fetal/neonatal adverse reactions Monoclonal antibodies are increasingly transported across the placenta as pregnancy progresses, with the largest amount transferred during the third trimester. Risks and benefits should be considered prior to administering live or live-attenuated vaccines to infants exposed to ENSPRYNG in utero [see Warnings and Precautions (5.1) ] . Data Animal Data Weekly subcutaneous administration of satralizumab-mwge (0, 2, or 50 mg/kg) to monkeys throughout pregnancy resulted in no adverse effects on postnatal development of the offspring; however, immune function was impaired in offspring at both doses.
Plasma exposures (C ave ) in dams at the low and high doses were approximately 3 and 100 times, respectively, that in humans at the recommended monthly maintenance dose of 120 mg.
🧒 Pediatric Use ▾
8.4Pediatric Use Safety and effectiveness in pediatric patients have not been established.
🧓 Geriatric Use ▾
8.5Geriatric Use Clinical studies of ENSPRYNG did not include sufficient numbers of patients aged 65 years and older to determine whether they respond differently from younger patients. However, population pharmacokinetic analyses in patients with NMOSD did not show that age affected the pharmacokinetics of satralizumab-mwge [see Clinical Pharmacology (12.3) ] . In general, caution should be used when dosing the elderly, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant diseases or other drug therapy.
🧬 Clinical Pharmacology ▾
12 CLINICAL PHARMACOLOGY
12.1Mechanism of Action The precise mechanism by which satralizumab-mwge exerts therapeutic effects in NMOSD is unknown but is presumed to involve inhibition of IL-6-mediated signaling through binding to soluble and membrane-bound IL-6 receptors.
12.2Pharmacodynamics The relationship between any of the pharmacodynamic effects of ENSPRYNG and clinical outcomes in NMOSD is unknown.
12.3Pharmacokinetics The pharmacokinetics of ENSPRYNG have been characterized both in Japanese and Caucasian healthy volunteers, and in NMOSD patients. The pharmacokinetics in NMOSD patients using the recommended dose were characterized using population pharmacokinetic analysis methods based on a database of 154 patients. The pharmacokinetics of satralizumab-mwge following administration of ENSPRYNG by prefilled syringe or autoinjector were comparable.
The concentration-time course of ENSPRYNG in patients with NMOSD was accurately described by a two-compartment population pharmacokinetic model with parallel linear and target-mediated (Michaelis-Menten) elimination and first-order subcutaneous absorption. ENSPRYNG clearance and volume parameters allometrically scaled by body weight (through power function with the fixed power coefficient of 0.75 and 1 for clearance and volume parameters, respectively). Body weight was shown to be a significant covariate, with clearance and V c for patients weighing 123 kg (97.5th percentile of the weight distribution) increased by 71.3% and 105%, respectively, compared to a patient weighing 60 kg.
Steady state pharmacokinetics were achieved after the loading period (8 weeks) as follows [mean (±SD)]: C min : 19.7 (12.2) mcg/mL, C max : 31.5 (14.9) mcg/mL, and AUC: 737 (386) mcg.mL/day. Absorption The bioavailability of satralizumab-mwge was 85%. Distribution Satralizumab-mwge undergoes biphasic distribution.
The central volume of distribution was
3.46 L and the peripheral volume of distribution was
2.07L. The inter-compartmental clearance was 0.336 L/day. Elimination The total clearance of satralizumab-mwge is concentration-dependent.
Linear clearance (accounting for approximately half of the total clearance at steady state using the recommended dose in NMOSD patients) is estimated to be 0.0601 L/day. The associated terminal t 1/2 is approximately 30 days (range 22 – 37 days) based on data pooled from Study 1 and Study 2. Metabolism The metabolism of satralizumab-mwge has not been directly studied, as antibodies are cleared principally by catabolism.
Excretion Monoclonal antibodies, including satralizumab-mwge, are not eliminated via renal or hepatic pathways. Specific Populations Population pharmacokinetic analyses in patients with NMOSD showed that age, gender, and race did not meaningfully influence the pharmacokinetics of satralizumab-mwge. Patients with Renal or Hepatic Impairment No formal studies of the effect of renal impairment or hepatic impairment on the pharmacokinetics of satralizumab-mwge were conducted.
Drug Interaction Studies No formal drug-drug interaction studies have been performed with ENSPRYNG. Based on population pharmacokinetic analyses of the available data, the impact of commonly used small molecule drugs on the pharmacokinetics of satralizumab-mwge remains inconclusive. Suppression of IL-6 signaling by treatment with ENSPRYNG, from the low baseline levels seen in Study 1 and Study 2, is expected to have a minor impact on exposure of concomitant medications metabolized by CYP450 enzymes.
The clinical significance of this is unknown.
🧬 Mechanism of Action ▾
12.1Mechanism of Action The precise mechanism by which satralizumab-mwge exerts therapeutic effects in NMOSD is unknown but is presumed to involve inhibition of IL-6-mediated signaling through binding to soluble and membrane-bound IL-6 receptors.
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING
16.1How Supplied ENSPRYNG (satralizumab-mwge) injection is available as a sterile, preservative-free, clear, colorless to slightly yellow solution for subcutaneous injection in a single-dose prefilled syringe (PFS) with needle safety device or a single-dose autoinjector. ENSPRYNG prefilled syringe and autoinjector are not made with natural rubber latex. Each ENSPRYNG carton contains one single-dose 120 mg/mL prefilled syringe (NDC 50242-007-01) or one single-dose 120 mg/mL autoinjector (NDC 50242-007-55).
16.2Storage and Handling Refrigerate at 2°C to 8°C (36°F to 46°F) in original carton to protect from light. Do not freeze. Do not shake. ENSPRYNG can be stored out of refrigeration for a maximum of 8 days at a temperature that does not exceed 30°C (86°F). If ENSPRYNG is removed from and returned to the refrigerator, the total combined time out of refrigeration should not exceed 8 days. Always keep in the original carton to protect from light.
📦 Storage and Handling ▾
16.2Storage and Handling Refrigerate at 2°C to 8°C (36°F to 46°F) in original carton to protect from light. Do not freeze. Do not shake. ENSPRYNG can be stored out of refrigeration for a maximum of 8 days at a temperature that does not exceed 30°C (86°F). If ENSPRYNG is removed from and returned to the refrigerator, the total combined time out of refrigeration should not exceed 8 days. Always keep in the original carton to protect from light.
📋 Description ▾
11 DESCRIPTION Satralizumab-mwge is a recombinant humanized anti-human interleukin 6 (IL-6) receptor monoclonal antibody based on a human IgG2 framework. Each light chain and heavy chain consists of 214 and 443 amino acids, respectively. Satralizumab-mwge is a glycoprotein with an approximate molecular weight of 143 kDa and is produced by recombinant DNA technology in Chinese hamster ovary cells.
The binding of satralizumab-mwge to the IL-6 receptor is pH-sensitive. ENSPRYNG (satralizumab-mwge) injection for subcutaneous administration is supplied as a sterile, clear, colorless to slightly yellow solution with no preservative with an approximate pH of 6. ENSPRYNG is supplied in a single-dose 1.0 mL prefilled syringe with a needle safety device or a single-dose 1.0 mL autoinjector that contains a prefilled syringe.
Each prefilled syringe or autoinjector delivers 1 mL of solution containing 120 mg satralizumab-mwge, L-arginine (26.1 mg), L-aspartic acid (pH adjustment), L-histidine (3.1 mg), poloxamer 188 (0.5 mg), and Water for Injection, USP.
💬 Information for Patients ▾
17 PATIENT COUNSELING INFORMATION Advise the patients to read the FDA-approved patient labeling ( Medication Guide and Instructions for Use ). Infections Inform patients that an increased risk of infections, including serious and potentially fatal infections, has been observed in patients treated with IL-6 receptor antagonists, including ENSPRYNG. Instruct patients to contact their healthcare provider immediately when symptoms suggesting infection (e.g., fever, chills, constant cough, or sore throat) appear during treatment [see Warning and Precautions (5.1) ] .
Vaccinations Advise patients to complete any required vaccinations at least 4 weeks prior to initiation of ENSPRYNG for live or live-attenuated vaccines and, whenever possible, at least 2 weeks prior to initiation of ENSPRYNG for non-live vaccines [see Warnings and Precautions 5.1 ]. Elevated Liver Enzymes Inform patients on the importance of liver enzyme testing [see Warnings and Precautions (5.2) ]. Decreased Neutrophil Counts Inform patients on the importance of neutrophil count testing [see Warnings and Precautions (5.3) ].
Hypersensitivity Reactions Inform patients about the signs and symptoms of hypersensitivity reactions and anaphylaxis and advise them to contact their healthcare provider immediately if these symptoms occur [see Warnings and Precautions (5.4) ] . Instruction on Injection Technique Instruct patients and caregivers to read the Instructions for Use before the patient starts using ENSPRYNG, and each time the patient gets a refill as there may be new information they need to know. Perform the first injection under the guidance of a qualified healthcare professional.
If a patient or caregiver is to administer subcutaneous ENSPRYNG, instruct him/her in injection techniques and assess his/her ability to inject subcutaneously to ensure proper administration of subcutaneous ENSPRYNG and the suitability for home use [see Dosage and Administration (2.3) and Instructions for Use ]. Instruct patients to remove the prefilled syringe or autoinjector from the refrigerator prior to use and allow it to sit at room temperature outside of the carton for 30 minutes. Do not warm ENSPRYNG in any other way.
Instruct patients to use the syringe or the autoinjector within 5 minutes of removing the cap. Do not remove the cap until ready to inject. Advise patients not to touch the green needle shield of the autoinjector or put the cap back on after it has been removed, as this may unintentionally activate the autoinjector.
Advise patients to consult their healthcare provider if the full dose is not received. A puncture-resistant container for disposal of syringes should be used and should be kept out of the reach of children. Instruct patients or caregivers in the technique as well as proper prefilled syringe or autoinjector disposal, and caution against reuse of these items.
Pregnancy Exposure Registry Encourage patients to enroll in the ENSPRYNG Pregnancy Registry if they become pregnant while taking ENSPRYNG. The Registry monitors fetal outcomes of pregnant women exposed to ENSPRYNG [see Use in Specific Populations (8.1) ].
💬 Medication Guide ▾
This Medication Guide has been approved by the U.S. Food and Drug Administration Issued: 6/2026 MEDICATION GUIDE ENSPRYNG ® (en-spryng) (satralizumab-mwge) injection, for subcutaneous use What is the most important information I should know about ENSPRYNG? ENSPRYNG may cause serious side effects including: 1.
Infections. ENSPRYNG can increase your risk of serious infections some of which can be life-threatening. Talk to your healthcare provider if you are being treated for an infection or call them right away if you think you have signs of an infection, with or without a fever, such as: chills, feeling tired, muscle aches, cough that will not go away or a sore throat. skin redness, swelling, tenderness, pain or sores on your body. diarrhea, belly pain, or feeling sick. burning when you urinate or urinating more often than usual.
Your healthcare provider will check if you have an infection and treat it if needed before you start or continue to take ENSPRYNG. Your healthcare provider should test you for hepatitis and tuberculosis (TB) before you start taking ENSPRYNG. All required vaccinations should be completed before starting ENSPRYNG.
People using ENSPRYNG should not be given 'live' or 'live-attenuated' vaccines. 'Live' or 'live-attenuated' vaccines should be given at least 4 weeks before you start ENSPRYNG. Your healthcare provider may recommend that you get a 'non-live' (inactivated) vaccine, such as some of the seasonal flu vaccines. If you plan to get a 'non-live' (inactivated) vaccine, it should be given, whenever possible, at least 2 weeks before you start ENSPRYNG.
2. Increased liver enzymes. Your healthcare provider should order blood tests to check your liver enzymes before and while you are taking ENSPRYNG.
Your healthcare provider will tell you how often you will need to have these blood tests. Make sure you get all of your follow-up blood tests as ordered by your healthcare provider. Your healthcare provider will tell you if you need to wait to start ENSPRYNG if your liver enzymes are increased.
3. Low neutrophil count. ENSPRYNG can cause a decrease in your neutrophil counts in your blood.
Neutrophils are white blood cells that help the body fight off bacterial infections. Your healthcare provider should order blood tests to check your neutrophil count while you are taking ENSPRYNG. See " What are the possible side effects with ENSPRYNG? " What is ENSPRYNG?
ENSPRYNG is a prescription medicine used to treat neuromyelitis optica spectrum disorder (NMOSD) in adults who are aquaporin-4 (AQP4) antibody positive. It is not known if ENSPRYNG is safe and effective in children. Do not take ENSPRYNG if you: are allergic to satralizumab-mwge or any of the ingredients in ENSPRYNG.
See " What are the ingredients in ENSPRYNG? " at the end of this Medication Guide for a complete list of ingredients in ENSPRYNG. have an active hepatitis B infection. have active or untreated inactive (latent) TB. Before you take ENSPRYNG, tell your healthcare provider about all of your medical conditions, including if you: have or think you have an infection. See " What is the most important information I should know about ENSPRYNG? " have liver problems. have ever had hepatitis B or are a carrier of the hepatitis B virus. have had or have been in contact with someone with tuberculosis. have had a recent vaccination or are scheduled to receive any vaccination. are pregnant, think that you might be pregnant, or plan to become pregnant.
It is not known if ENSPRYNG will harm your unborn baby. Pregnancy Registry : There is a registry for pregnant women who take ENSPRYNG. The purpose of this registry is to check the health of the pregnant mother and her baby.
If you are pregnant or become pregnant while taking ENSPRYNG, talk to your healthcare provider about how you can join this pregnancy registry, or you may contact the registry at 1-833-277-9338 to enroll. are breastfeeding or plan to breastfeed. It is not known if ENSPRYNG passes into your breast…