Ocrelizumab (Ocrevus) is a CD20-targeted B-cell depleting agent, indicated 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 mandatory.

How to Administer Ocrelizumab (Ocrevus)

Administration Regimen

Initial Dose: Administered as two separate infusions, 300 mg each, with a 2-week interval (total dose: 600 mg). Each infusion takes approximately 2.5 hours.

Subsequent Maintenance Dose: A single 600 mg infusion every 6 months. The infusion duration can be shortened to 2 hours (for patients with no history of 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: Closely monitor patients for infusion reactions (e.g., pruritus, rash, dyspnea) during the infusion and for at least 1 hour after completion.

Dilution and Storage: The drug 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% of the original speed; the rate can be gradually restored once symptoms resolve.

Severe Reactions: Immediately discontinue the infusion and provide symptomatic treatment. After complete resolution of symptoms, restart the infusion at 50% of the original rate.

Life-Threatening Reactions: Permanently discontinue Ocrevus.

Administration of Ocrelizumab (Ocrevus) 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 benefits and risks before deciding to discontinue the drug 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 alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase, and bilirubin. If symptoms of liver injury (e.g., jaundice, abdominal pain) occur during treatment, discontinue the drug.

Renal Impairment: No dosage adjustment is needed for mild impairment. Data on moderate to severe impairment are insufficient, so caution is advised.

Patients at Risk of Infections

Active Infections: Delay drug administration until the infection is fully resolved.

Hepatitis B Carriers (HBcAb+ or HBsAg+): Treatment must be conducted under the guidance of a hepatologist, and HBV DNA levels should be monitored.

Hypogammaglobulinemia: For patients with baseline IgG levels below the 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 starting treatment. Live vaccines are contraindicated during treatment and before B-cell recovery.

Inactivated Vaccines: Administer 2 weeks before treatment; vaccine efficacy may be reduced during treatment.