Ocrelizumab (Ocrevus) is a CD20-targeted B-cell depleting agent used for the treatment of relapsing multiple sclerosis (RMS) and primary progressive multiple sclerosis (PPMS). It is administered via intravenous infusion, and strict adherence to dosage regimens and monitoring requirements is necessary.
How to Use Ocrelizumab (Ocrevus)
Administration Regimen
Initial Dose: Administered as two infusions, 300 mg each, with a 2-week interval (total dose of 600 mg). Each infusion takes approximately 2.5 hours.
Subsequent Maintenance Dose: A single 600 mg infusion every 6 months. The infusion time can be shortened to 2 hours (for patients with no previous severe infusion reactions) or maintained at 3.5 hours.
Pre-infusion Prophylaxis: Before each infusion, intravenous methylprednisolone (or an equivalent glucocorticoid) and an antihistamine (e.g., diphenhydramine) must be administered to reduce the risk of infusion reactions.
Infusion Precautions
Monitoring Requirements: During the infusion and for at least 1 hour after completion, closely monitor the patient for infusion reactions (such as pruritus, rash, dyspnea, etc.).
Dilution and Storage: The medication must be diluted with 0.9% sodium chloride injection to a final concentration of 1.2 mg/mL. The diluted solution must be used within 8 hours (including infusion time) at room temperature, or refrigerated for no more than 24 hours.
Dosage Adjustment of Ocrelizumab (Ocrevus)
Management of Infusion Reactions
Mild to Moderate Reactions: Reduce the infusion rate to 50%. The rate can be gradually restored after symptoms resolve.
Severe Reactions: Immediately discontinue the infusion and provide symptomatic treatment. After symptoms are completely resolved, restart the infusion at 50% of the original rate.
Life-Threatening Reactions: Permanently discontinue Ocrevus.
Ocrelizumab (Ocrevus) Use in Special Populations
Pregnancy and Lactation
Pregnancy: May cause fetal harm based on animal data; contraindicated during pregnancy. Women of childbearing age must use effective contraceptive measures during treatment and for 6 months after the last dose.
Lactation: Whether ocrelizumab is excreted in human milk is unknown. It is recommended to weigh the pros and cons before deciding to discontinue the medication or stop breastfeeding.
Pediatric and Geriatric Patients
Pediatric Patients: Efficacy has not been established; use is not recommended.
Geriatric Patients: Clinical data are limited. No dosage adjustment is required, but enhanced monitoring for infections is necessary.
Patients with Hepatic or Renal Impairment
Hepatic Impairment: Before treatment, test ALT, AST, alkaline phosphatase, and bilirubin. If symptoms of liver injury (such as jaundice, abdominal pain) occur during treatment, discontinue the medication.
Renal Impairment: No dosage adjustment is needed for mild impairment. Data on moderate to severe impairment are insufficient, so caution is required.
Patients at Risk of Infections
Active Infections: Delay administration until the infection is resolved.
Hepatitis B Carriers (HBcAb+ or HBsAg+): Treatment must be conducted under the guidance of a hepatologist, and HBV DNA should be monitored.
Hypogammaglobulinemia: For patients with baseline IgG < lower limit of normal (LLN), assess the risk of infection and regularly monitor immunoglobulin levels during treatment.
Vaccination
Live Vaccines: Complete vaccination 4 weeks before treatment. Live vaccines are contraindicated during treatment and before B-cell recovery.
Inactivated Vaccines: Administer 2 weeks before treatment. Efficacy may be reduced during treatment.
