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For US Healthcare Professionals

The safety and side effects of ENSPRYNG were studied in a diverse group of people

ENSPRYNG is a treatment that can be taken long-term, backed by a median* of 5 years of safety data

Jennifer — taking ENSPRYNG since 2023

ENSPRYNG has an established safety profile, which means it has been well-studied. Two clinical studies found that side effects seen with ENSPRYNG were similar to those seen with placebo.

The rates of serious side effects were similar between ENSPRYNG and placebo†

Two charts show efficacy in two studies.

*A median is a numeric middle. That means that in a list of numbers, the median is the number in the middle.
†The safety population included patients who received at least 1 dose of ENSPRYNG or placebo and included AQP4-positive and AQP4-negative patients.

The most common side effects include:

sore throat and runny nose (nasopharyngitis)
rash
fatigue
extremity pain
headache
upper respiratory tract infection
nausea
inflammation of the stomach lining (gastritis)
joint pain (arthralgia)

Please scroll down to read the Important Safety Information for more details about common and serious side effects. 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 FDA at 800-FDA-1088. You may also report side effects to Genentech at 888-835-2555. For more information, call 844-NSPRYNG.

The possible serious side effects include:

Infections

You should call your doctor right away if you have symptoms such as chills, a cough that won't go away, skin redness, diarrhea, or other signs of infection.

Increased liver enzymes

Your doctor should order blood tests to check your liver enzymes before and while you are taking ENSPRYNG. If a blood test shows that your liver enzymes are increased before starting treatment, your doctor will let you know if you need to wait to take ENSPRYNG.

Low neutrophil counts

Neutrophils are white blood cells that help your body fight off bacterial infections. Taking ENSPRYNG may cause your neutrophil count to go down. Your healthcare provider should order blood tests to check your neutrophil count while you are taking ENSPRYNG.

Serious allergic reactions

Tell your doctor if you've experienced hives, rash, or flushing after your injection. Serious allergic reactions due to ENSPRYNG may be life-threatening, so seek medical attention right away if you notice shortness of breath or trouble breathing, dizziness or feeling faint, chest pain, or more.

Established long-term safety profile

Backed by a median of 5 years of safety data: 106 patients who completed Study 1 or Study 2 were included in a long-term, open-label study and have been taking ENSPRYNG for a median of 5 years.‡

Long-term safety rates for ENSPRYNG were similar to rates in Study 1 and Study 2. These rates included side effects, serious side effects, infections, and serious infections.

‡An open-label study means that patients and the study staff knew ENSPRYNG was the provided treatment. Conclusions should not be drawn on the basis of an open-label study, as the results from this study were not used to support the approval of ENSPRYNG.

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NEXT: Important Safety Information

Important Safety Information & Indication

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.

Who should not receive ENSPRYNG?

Do not take ENSPRYNG if you:

  • are allergic to ENSPRYNG or any of the ingredients in ENSPRYNG.
  • have an active hepatitis B infection.
  • have active or untreated inactive (latent) tuberculosis.
What is the most important information I should know about ENSPRYNG?

ENSPRYNG may cause serious side effects including:

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

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 milk. Talk to your healthcare provider about the best way to feed your baby if you take ENSPRYNG.

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

What are the most common side effects of ENSPRYNG?
The most common side effects of ENSPRYNG include:

  • sore throat, runny nose (nasopharyngitis)
  • rash
  • fatigue
  • extremity pain
  • headache
  • upper respiratory tract infection
  • nausea
  • inflammation of the stomach lining (gastritis)
  • joint pain (arthralgia)

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 FDA at 1-800-FDA-1088. You may also report side effects to Genentech at 1-888-835-2555.

For more information, call 1-844-NSPRYNG.

For additional safety information, please see the full Prescribing Information and Medication Guide.

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