Ocrelizumab (Ocrevus) is a CD20-directed cytolytic antibody used for the treatment of relapsing multiple sclerosis (RMS) and primary progressive multiple sclerosis (PPMS) in adults. As a prescription medication, patients must fully understand its safety profile, side effects, and medication precautions.

What Are the Side Effects of Ocrelizumab (Ocrevus)

Infusion Reactions

Incidence rate: 34-40% (most common during the first infusion).

Symptoms include pruritus, rash, urticaria, erythema, bronchospasm, throat irritation or pain, dyspnea, facial flushing, hypotension, fever, fatigue, headache, dizziness, nausea, tachycardia, etc.

Infections

Upper respiratory tract infections (40% in RMS trials vs. 33% with REBIF).

Lower respiratory tract infections (8% vs. 5%).

Skin infections.

Herpes virus infections (including shingles: 2.1%, herpes simplex: 0.7%).

Other Common Adverse Reactions

Back pain (6%).

Limb pain (5%).

Depression (8%).

Cough (7%).

Diarrhea (6%).

Serious Side Effects to Watch for with Ocrelizumab (Ocrevus)

Severe Infusion Reactions

Approximately 0.3% of patients experience severe infusion reactions requiring hospitalization.

Although fatal infusion reactions have not been reported, allergic reactions may occur. Symptoms may appear within 24 hours after infusion.

Increased Infection Risk

Severe infections: Including life-threatening or fatal bacterial, viral, parasitic, and fungal infections.

Herpes infections: May cause central nervous system (CNS) infections (encephalitis and meningitis), intraocular infections, and disseminated skin and soft tissue infections.

Hepatitis B virus (HBV) reactivation: May lead to fulminant hepatitis, liver failure, and even death.

Progressive Multifocal Leukoencephalopathy (PML)

PML is a rare opportunistic brain infection caused by the JC virus, which usually results in death or severe disability.

Symptoms include progressive weakness of one side of the body, visual disturbances, and changes in thinking, memory, and orientation.

Decreased Immunoglobulins

Reduced immunoglobulin G (IgG) levels may occur during treatment, which is associated with an increased risk of severe infections.

Long-term hypogammaglobulinemia may require intravenous immunoglobulin therapy.

Ocrelizumab (Ocrevus) Medication Precautions

Contraindicated Populations

Patients with active HBV infection.

Patients with a history of life-threatening infusion reactions to ocrelizumab.

Pre-Medication Assessment

HBV screening (HBsAg and anti-HB tests).

Quantitative detection of serum immunoglobulins.

Liver function tests (ALT, AST, alkaline phosphatase, and bilirubin).

Vaccination assessment (live vaccines must be administered at least 4 weeks before medication initiation).

Monitoring Requirements

Closely monitor during infusion and for at least 1 hour after completion.

Regularly check immunoglobulin levels (especially in cases of recurrent severe infections).

Seek medical attention promptly if infection symptoms, neurological symptoms, or abnormal liver function occur.