Enspryng

Approved Uses

Enspryng is used to treat neuromyelitis optica spectrum disorder (NMOSD) in adults. It is specifically indicated for patients who are anti-aquaporin-4 (AQP4) antibody positive. NMOSD is a rare and serious autoimmune condition that primarily affects the central nervous system, specifically the optic nerves and the spinal cord.

The medication is used to help reduce the risk of relapses, also known as attacks or flares. In people with NMOSD, the immune system mistakenly attacks healthy cells, which can lead to permanent damage. These attacks may cause symptoms such as:

• Vision loss or blindness
• Muscle weakness or paralysis in the limbs
• Loss of sensation
• Bladder and bowel problems

Before starting treatment, a healthcare provider will perform a blood test to confirm the presence of AQP4 antibodies, as Enspryng is only approved for patients who test positive for this biomarker.

Mechanism of Action

Enspryng belongs to a class of drugs known as interleukin-6 (IL-6) receptor antagonists. It is a laboratory-made protein called a monoclonal antibody that is designed to recognize and attach to a specific target in the body.

The target for Enspryng is the IL-6 receptor. IL-6 is a naturally occurring protein that acts as a chemical messenger in the immune system. While IL-6 helps the body fight infections, having too much of it can lead to excessive inflammation and cause the immune system to attack the body's own healthy tissues.

Reducing Immune Attacks

In neuromyelitis optica spectrum disorder (NMOSD), the immune system attacks the optic nerves and the spinal cord. This often involves the production of harmful antibodies and significant inflammation. By blocking the IL-6 receptor, Enspryng prevents the IL-6 protein from triggering these inflammatory responses.

This process helps to:

• Limit inflammation in the central nervous system.
• Reduce the activity of immune cells that contribute to nerve damage.
• Lower the frequency of disease relapses or attacks.

Enspryng is used specifically in adults who have a certain type of NMOSD where the body produces antibodies against a protein called aquaporin-4 (AQP4).

Common Side Effects

Many people using Enspryng experience mild side effects. These may include:

• Injection site reactions, such as redness, itching, pain, or swelling where the shot was given
• Joint or muscle pain
• Headache
• Common cold symptoms, including sore throat and runny or stuffy nose
• Rash or itchy skin
• Fatigue
• Nausea or stomach inflammation (gastritis)

Serious Side Effects

While less common, some side effects can be serious and require medical attention. These include:

• Serious infections: Because this medication affects the immune system, it may increase the risk of infections. Symptoms can include fever, chills, persistent cough, or burning during urination.
• Liver problems: This medication can cause changes in liver function. Seek medical help for yellowing of the skin or eyes (jaundice), dark urine, or pain in the upper right stomach area.
• Allergic reactions: Signs of a severe reaction include hives, swelling of the face or throat, and difficulty breathing.
• Laboratory changes: Enspryng may cause a decrease in white blood cell counts or an increase in cholesterol and triglyceride levels.

Infection Risk

Enspryng may lower the immune system's ability to fight infections. Treatment should not be started if there is an active, serious infection. Healthcare providers typically screen for tuberculosis and Hepatitis B before the first dose is administered.

Liver Function and Blood Monitoring

This medication can cause changes in certain laboratory test results. Regular blood tests are usually required to monitor for the following:

• Liver enzymes: Increases in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels may occur.
• Neutrophil counts: A decrease in white blood cells (neutropenia) can happen, which may increase the risk of infection.

Vaccinations

Live or live-attenuated vaccines should not be given during treatment with Enspryng. It is recommended that all required immunizations be completed at least four weeks before starting the medication.

Hypersensitivity Reactions

Serious allergic reactions are possible. Enspryng should not be used by individuals with a known hypersensitivity to satralizumab or any of the ingredients in the formulation.

Pregnancy

The safety of Enspryng during pregnancy has not been fully established. There are no adequate and well-controlled studies in pregnant women to determine if the drug poses a risk to the fetus. Animal studies involving monkeys did not show adverse effects on pregnancy or fetal development, but animal results do not always predict human response.

If you are of childbearing potential, your healthcare provider may recommend using effective contraception during treatment and for at least 3 months after your last dose. If you become pregnant while taking Enspryng, you should inform your doctor right away.

Breastfeeding

It is unknown if Enspryng passes into breast milk or if it could affect a nursing baby. Because the potential for serious adverse reactions in a breastfed infant is unknown, you should discuss the risks and benefits of breastfeeding with your healthcare provider. The decision to breastfeed while using this medication should consider the clinical need for the drug and the health benefits of breastfeeding for the infant.

Dosage Forms

Enspryng is supplied as a sterile, preservative-free solution for subcutaneous injection. It is available in the following delivery format:

• Single-dose prefilled syringe: A ready-to-use syringe intended for injection into the fatty tissue under the skin.

This medication is designed for single use. Each syringe should be disposed of after use, even if medication remains in the syringe.

FDA Approval Status

Enspryng (satralizumab-mwge) received FDA approval in August 2020. It is classified as an interleukin-6 (IL-6) receptor antagonist and was the first subcutaneous treatment approved for neuromyelitis optica spectrum disorder (NMOSD) that allows for self-administration at home.

Approved Indications

The medication is specifically approved for use in adult patients who have tested positive for the anti-aquaporin-4 (AQP4) antibody. It is not approved for patients who are AQP4 antibody negative.

Regulatory Designations and Safety

During the approval process, the FDA granted Enspryng Orphan Drug designation, which is a status given to drugs intended to treat rare diseases. There are currently no boxed warnings or Risk Evaluation and Mitigation Strategy (REMS) requirements associated with this drug. However, regulatory labeling includes warnings about the risk of serious infections and the need to monitor liver enzymes and neutrophil counts during treatment.

Factors Affecting Cost

Several factors can influence the total cost of Enspryng treatment:

• Insurance Coverage: Your out-of-pocket expenses, such as copays or coinsurance, depend on your specific health insurance plan and its formulary.
• Specialty Pharmacy: Enspryng is a specialty medication and is typically dispensed through specialty pharmacies rather than standard retail pharmacies.
• Administration: While Enspryng is designed for subcutaneous injection and can be self-administered at home, costs may vary if it is administered by a healthcare professional in a clinic or office setting.

Generic and Biosimilar Status

Enspryng is a brand-name biologic medication. There are currently no biosimilar or generic versions available. Brand-name specialty drugs generally have higher costs because they lack competition from lower-cost alternatives.

Financial Assistance Programs

The manufacturer may offer support programs to help manage the cost of Enspryng. These options often include:

• Copay Cards: Eligible patients with commercial insurance may be able to use copay cards to reduce their monthly out-of-pocket costs.
• Patient Assistance Programs: Programs may be available for individuals who are uninsured or underinsured to help them access the medication at a lower cost or for free.

It is recommended to contact your insurance provider or the manufacturer directly to understand the specific costs and assistance options available for your situation.