Satralizumab

Satralizumab (brand name Enspryng) is a prescription medicine used to treat two conditions in adults: neuromyelitis optica spectrum disorder (NMOSD) and thyroid eye disease (TED).

In NMOSD, a rare autoimmune disease that inflames the central nervous system and can damage the optic nerves, spinal cord, and brain, satralizumab lowers the risk of relapse. It is prescribed for adults who are anti-aquaporin-4 (AQP4) antibody positive, so your doctor will test for this antibody before you start.

In thyroid eye disease (TED), an autoimmune condition that inflames the tissue around the eyes and can cause eye bulging (proptosis), double vision, and pain, satralizumab is approved for adults at any level of disease activity or duration.

Satralizumab is an interleukin-6 (IL-6) receptor antagonist, a type of interleukin inhibitor. It blocks IL-6, an immune system protein that drives the inflammation seen in both conditions. The medicine is given as a subcutaneous (under-the-skin) injection, starting with three loading doses and then a maintenance dose every 4 weeks, and it can be self-injected at home after training.

Enspryng is made by Genentech, a member of the Roche Group. It first received FDA approval on August 14, 2020, for NMOSD in anti-AQP4 antibody-positive adults, based on the SAkuraStar (NCT02073279) and SAkuraSky (NCT02028884) trials, which showed a significant reduction in relapse risk versus placebo. The FDA later expanded approval to include thyroid eye disease in adults.

Use satralizumab exactly as prescribed. Follow all directions on your prescription label and read all medication guides and Instructions for Use. Ask your doctor or pharmacist if you do not understand any instructions.

Satralizumab is injected under the skin. Your healthcare provider will give the first injection and can teach you or your caregiver how to inject it correctly at home.

Satralizumab is given as 3 loading doses, each 2 weeks apart (at Weeks 0, 2, and 4), followed by maintenance doses once every 4 weeks. For TED, the dose depends on your body weight. Your doctor will decide how long to treat you.

Take satralizumab out of the refrigerator and let it reach room temperature for 30 minutes before injecting. Do not warm it in any other way. Use the prefilled syringe or autoinjector within 5 minutes of removing the cap, and do not remove the cap until you are ready to inject. Do not touch the green needle shield of the autoinjector or put the cap back on after it has been removed, as this may accidentally activate it.

Do not shake. Do not use the medicine if it is cloudy or discolored, has particles in it, or if the prefilled syringe or autoinjector is damaged or has been dropped. The solution should be clear and colorless to slightly yellow.

Inject satralizumab into the abdomen (stomach area) or thigh. Do not inject into the 2-inch (5 cm) area around your navel. Change (rotate) injection sites each time, keeping each injection at least 1 inch (2.5 cm) from your last one. Do not inject into moles, scars, or skin that is tender, bruised, red, hard, or broken.

Inject all of the medicine in the prefilled syringe or autoinjector. Each one is for a single use only; throw it away after use, even if some medicine is left inside. Tell your doctor if you did not receive the full dose.

Do not inject this medicine while you have signs of an active infection. Call your doctor if you have any signs of infection (fever, chills, cough, sore throat). You will need frequent medical tests, including blood tests to check your liver enzymes and neutrophil counts.

If you stop using satralizumab for a period of time, you may need to restart with loading doses. Follow your doctor's instructions carefully.

Satralizumab affects your immune system. You may get infections more easily, even serious or fatal infections. Call your doctor if you have signs of infection, such as fever, chills, cough, tiredness, muscle pain, diarrhea, stomach cramps, increased or painful urination, or skin sores, redness, swelling, or tenderness. Your healthcare provider will check for an infection and treat it if needed before you start or continue this medicine.

Your healthcare provider should test you for hepatitis B and tuberculosis (TB) before you start satralizumab. You should not use satralizumab if you have an active hepatitis B infection or active or untreated latent tuberculosis.

Satralizumab can raise your liver enzymes and lower your neutrophil (white blood cell) counts, so you will need blood tests before and during treatment.

You should not use satralizumab if you are allergic to it or to any of its ingredients, or if you have:

• an active hepatitis B infection; or
• active or untreated latent tuberculosis.

Tell your doctor if you have ever had tuberculosis, if anyone in your household has tuberculosis, or if you have recently traveled to an area where tuberculosis is common.

Tell your doctor if you have ever had:

• an active or chronic infection;
• liver problems, or hepatitis B (or if you are a carrier of hepatitis B); or
• a recent vaccine, or a vaccine that is scheduled.

Make sure you are up to date on your vaccines before you begin treatment with satralizumab. You should not receive a "live" vaccine for at least 4 weeks before starting satralizumab. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and the nasal flu (influenza) vaccine.

Whenever possible, you should not receive a "non-live" (inactivated) vaccine for at least 2 weeks before starting satralizumab. Non-live vaccines include the flu (influenza) shot and injected vaccines for hepatitis A, polio, and rabies.

Tell your doctor if you are pregnant or breastfeeding. If you use satralizumab while you are pregnant, make sure any doctor caring for your new baby knows that you used satralizumab during pregnancy, because it could affect your baby's vaccination schedule. There is a pregnancy registry for women with NMOSD who are exposed to satralizumab during pregnancy; you can enroll by calling 1-833-277-9338.

Common satralizumab side effects

The most common side effects of satralizumab in people treated for NMOSD (reported in 15% or more of patients) are:

• Nasopharyngitis (cold-like symptoms)
• Headache
• Upper respiratory tract infection
• Gastritis (irritation of the stomach lining)
• Rash
• Joint pain (arthralgia)
• Pain in the arms or legs
• Fatigue (tiredness)
• Nausea

In the NMOSD study where satralizumab was used on its own (Study 1), side effects reported in at least 10% of patients included rash (17%), joint pain (17%), pain in an arm or leg (15%), fatigue (15%), nausea (15%), nasopharyngitis (12%), itchy skin (10%), depression (10%), cellulitis, a skin infection (10%), neutropenia, or low levels of neutrophils in the blood (10%), increased blood creatine phosphokinase (10%), and falls (10%).

In people treated for thyroid eye disease (TED), the most common side effects (reported in 5% or more of patients) are upper respiratory tract infection and increased alanine aminotransferase (ALT), a liver enzyme.

Serious satralizumab side effects

Allergic reactions. Stop using satralizumab and get emergency medical help if you have signs of an allergic reaction: hives; feeling light-headed; stomach pain, vomiting; difficulty breathing; or swelling of your face, lips, tongue, or throat. Serious allergic reactions, including anaphylaxis, have been reported with IL-6 receptor antagonists.

Serious infections. Satralizumab affects your immune system, so you may get infections more easily, even serious or life-threatening infections. Call your doctor right away if you have signs of infection such as:

• fever, chills, night sweats;
• sore throat, ongoing cough, feeling very tired;
• muscle pain;
• diarrhea, stomach cramps;
• loss of appetite, weight loss;
• increased urination, burning when you urinate; or
• skin sores, redness, swelling, or tenderness.

Increased liver enzymes. Satralizumab can raise the level of liver enzymes in your blood. Your healthcare provider will order blood tests to check your liver enzymes before you start and while you use satralizumab.

Low neutrophil count. Satralizumab can lower your neutrophils, a type of white blood cell that helps fight infection. Your provider will check your neutrophil count with blood tests during treatment.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Usual adult dose for neuromyelitis optica spectrum disorder (NMOSD):

Loading dose: 120 mg by subcutaneous injection at Weeks 0, 2, and 4.Maintenance dose: 120 mg by subcutaneous injection every 4 weeks.

Usual adult dose for thyroid eye disease (TED): dosing is based on body weight.

• 40 kg to 100 kg (about 88 to 220 lb): 120 mg at Weeks 0, 2, and 4, then 120 mg every 4 weeks.
• More than 100 kg (about 220 lb): 180 mg at Weeks 0, 2, and 4, then 180 mg every 4 weeks.

Satralizumab has not been studied in people with TED who weigh less than 40 kg.

Uses: treatment of neuromyelitis optica spectrum disorder (NMOSD) in adults who are anti-AQP4 antibody positive; and treatment of thyroid eye disease (TED) in adults.

Call your doctor for instructions if you miss a dose. Depending on how long it has been since your last dose, you may need to restart with loading doses. If you stopped treatment because of a side effect or infection, carefully follow your doctor's instructions about when to restart.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Do not inject satralizumab into scars, moles, broken skin, or skin that is red, bruised, tender, or hard.

Do not receive live or live-attenuated vaccines while using satralizumab.

No formal drug interaction studies have been done with satralizumab. Tell your doctor about all the medicines you use, including prescription and over-the-counter medicines, vitamins, and herbal products.

Because satralizumab blocks IL-6, it may change how your body handles certain medicines that are broken down by liver enzymes (CYP450 enzymes), especially medicines where the dose must be carefully controlled. Your doctor may need to monitor you or adjust the dose of these medicines.

Do not receive live or live-attenuated vaccines during treatment with satralizumab.

• Store Enspryng in the refrigerator between 36°F and 46°F (2°C and 8°C) in the original carton.
• Protect from light.
• Do not freeze, and do not use the medicine if it has been frozen.
• Do not shake.
• Enspryng can be kept out of the refrigerator for up to 8 days at a temperature that does not go above 86°F (30°C). If it is removed from and returned to the refrigerator, the total combined time out of the refrigerator should not be more than 8 days.
• Keep Enspryng and all medicines out of the reach of children.

Active ingredient: satralizumab-mwge

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