Enspryng Satralizumab Injection

1. Indications and Usage
Neuromyelitis Optica Spectrum Disorder (NMOSD):
Indicated for the treatment of adult and pediatric patients (12 years of age and older and weighing at least 40 kg) with AQP4-IgG-positive NMOSD.
2. Dosage and Administration
Route of Administration:
For Subcutaneous Injection ONLY.
Recommended Dosage:
Loading Doses: 120 mg administered at Week 0, Week 2, and Week 4.
Maintenance Dose: 120 mg administered every 4 weeks thereafter.
Administration:
Patients may self-inject if their physician determines it is appropriate and they receive proper training.
If a dose is missed, administer as soon as possible and resume dosing every 4 weeks.
3. Mechanism of Action
IL-6 Receptor Blockade:
Satralizumab is a recombinant humanized IgG2 monoclonal antibody that binds to both membrane-bound and soluble interleukin-6 receptors (IL-6R).
Blocking Signaling:
By binding to IL-6R, satralizumab inhibits the binding of IL-6 to its receptor, thereby blocking the IL-6 signaling pathway, which is involved in inflammation and immune responses.
Antibody Recycling:
Satralizumab is designed to dissociate from the IL-6 receptor in a pH-dependent manner and be recycled back to the peripheral blood, which prolongs its elimination half-life (approximately 11 to 13 days) and allows for less frequent dosing.
4. Safety and Warnings
Infections (Boxed Warning):
Satralizumab may increase the risk of infections. Screen for tuberculosis (TB) and Hepatitis B (HBV) prior to initiation. Do not administer during active infection.
Hepatitis B Reactivation:
Monitor HBV viral load and liver function in carriers.
Elevated Liver Enzymes:
Monitor ALT and AST levels. Dose interruption or discontinuation may be necessary if significant elevations occur.
Neutropenia:
Monitor neutrophil counts during treatment.
Vaccinations:
Avoid live vaccines during treatment. Complete necessary vaccinations at least 4 weeks prior to initiating therapy.
5.Adverse Reactions
Most Common (Incidence ≥15%):
Nasopharyngitis, headache, upper respiratory tract infection, gastritis, rash, arthralgia, extremity pain, fatigue, and nausea.
6.Drug Interactions
CYP450 Substrates:
Chronic inflammation can increase IL-6 levels, which may suppress CYP450 enzyme activity. Blocking IL-6 signaling with satralizumab may normalize CYP450 activity.
Caution: Monitor dosage of CYP1A2, CYP2C9, or CYP3A4 substrates (e.g., theophylline, warfarin) when starting or stopping satralizumab.
7.Pharmaceutical Information
Chemical Composition:
Active Ingredient: Satralizumab.
Available Strength: 120 mg/1 mL in a single-use prefilled syringe.
Appearance: Clear to slightly opalescent, colorless to pale yellow liquid.
Storage: Store at 2°C to 8°C (36°F to 46°F) in the original carton to protect from light.