Pronunciation: en-spryng
Generic name: satralizumab-mwge
Dosage form: single-dose prefilled syringe for subcutaneous use (120 mg/mL)
Drug class: Interleukin inhibitors

Medically reviewed by Carmen Pope, BPharm. Last updated on Aug 31, 2025.

What is Enspryng? Understanding Satralizumab for Neuromyelitis Optica

Enspryng is used to treat neuromyelitis optica spectrum disorder (NMOSD) in adults who are aquaporin-4 (AQP4) antibody-positive. It can be self-administered as a subcutaneous injection every 4 weeks after an initial loading dose phase.

Key Information at a Glance

• Generic name: satralizumab-mwge
• Dosage form: 120 mg/mL single-dose prefilled syringe
• Administration: Subcutaneous injection every 4 weeks
• Drug class: Interleukin inhibitors
• FDA approval: August 14, 2020.

How does Enspryng Work for NMOSD Treatment?

Enspryng works by targeting the interleukin-6 (IL-6) pathway, which plays a crucial role in the inflammatory processes associated with NMOSD. This medication binds to both soluble and membrane-bound IL-6 receptors, effectively disrupting the inflammatory cascade that damages the optic nerves and spinal cord in neuromyelitis optica patients.

Enspryng Side Effects

Common Side Effects

The most common side effects of Enspryng are:

• Upper respiratory infections (nasopharyngitis, sore throat, runny nose)
• Skin reactions (rash, injection site reactions)
• General symptoms (fatigue, headache)
• Musculoskeletal effects (extremity pain, joint pain)
• Gastrointestinal issues (nausea, gastritis).

Serious Side Effects and Warnings

Infection Risk Warning

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, a 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 urinate 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 this medicine. 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 this medication. 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.

Liver Function Monitoring

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.

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 this medication.

Serious allergic reactions

Serious allergic reactions that may be life-threatening have happened with other medicines like Enspryng. Tell your healthcare provider before taking your next dose if you have had hives, rash, or flushing after your injection. Seek medical attention right away if you have any symptoms of a serious allergic reaction, such as:

• shortness of breath or trouble breathing
• swelling of your lips, face, or tongue
• dizziness or feeling faint
• moderate or severe stomach (abdominal) pain or vomiting
• chest pain.

It is not known if this medication is safe and effective in children.

These are not all the possible side effects of Enspryng. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects to Genentech at 1-888-835-2555.

Related/similar drugs

Before taking

Do not take Enspryng if you:

• are allergic to satralizumab-mwge, Enspryng, or any of the excipients in the injection
• 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
• 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
• are breastfeeding or plan to breastfeed.

If you have an active infection, your healthcare provider should delay Enspryng administration until the infection is resolved.

Pregnancy

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.

Breastfeeding

It is not known if Enspryng passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby if you receive this medicine.

Tell your healthcare provider about all the medicines you are taking, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

How is Enspryng administered?

See the Instructions for Use provided with the medication guide for instructions about the right way to prepare and inject Enspryng.

• Enspryng is given by an injection under the skin (subcutaneously).
• It may be administered into the abdomen (but not within 2 inches of the navel) or the upper, outer thigh.
• Rotate injection sites with each administration. Do not give an injection into moles, scars, or areas where the skin is tender, bruised, red, hard, or not intact.
• If your healthcare provider decides that you or your caregiver can give your injections of Enspryng, you or your caregiver should receive training on the right way to prepare and inject Enspryng.

Always inject all of the medicine in the syringe.

• The first 3 injections (loading period) of Enspryng are administered once every 2 weeks.
• After this, an injection of Enspryng is given every 4 weeks (maintenance period).
• Keep taking Enspryng once every 4 weeks for as long as your healthcare provider tells you to.

Dosing information

Loading Dose Phase of Enspryng for NMOSD (First 3 Injections)

• Week 0: 120 mg subcutaneous injection
• Week 2: 120 mg subcutaneous injection
• Week 4: 120 mg subcutaneous injection

Maintenance Phase Enspryng Dose for NMOSD (Ongoing Treatment)

• Every 4 weeks: 120 mg subcutaneous injection

What happens if I miss a dose?

If you miss a dose of Enspryng, talk to your healthcare provider about restarting dosing.

What other drugs will affect this medicine?

Tell your healthcare provider about all the medicines you are taking, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Storage

Store Enspryng in the refrigerator between 36°F to 46°F (2°C to 8°C) in the original carton.

• Protect from light.
• Do not freeze or use the syringe if it has been frozen.
• Do not shake.

Enspryng, if unopened, can be removed from and returned to the refrigerator, if needed. The total combined time out of the refrigerator should not be more than 8 days at a temperature that does not go above 86°F (30°C).

Ingredients

Active ingredient: satralizumab-mwge

Inactive ingredients: L-arginine, L-histidine, poloxamer 188, L-aspartic acid, and Water for Injection.

Available as a 120 mg/mL injection in a single-dose prefilled syringe.

Manufacturer

Enspryng (satralizumab) is manufactured by Genentech Inc., a member of the Roche Group with headquarters in South San Francisco, California. Enspryng was developed by Chugai Pharmaceutical, a Japanese subsidiary of Roche.

Frequently Asked Questions About Enspryng

How long does Enspryng take to work?

Individual response varies, but clinical benefits may be observed within the first few months of treatment.

Can I travel with Enspryng?

Yes, with proper cold storage arrangements. Consult your healthcare provider for travel guidelines.

Enspryng Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for Enspryng.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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