Common Side Effects of Ocrevus
Ocrevus (ocrelizumab), used for multiple sclerosis (MS) and certain lymphomas, causes infusion-related reactions in over half of patients. These include itching, rash, nausea, fatigue, headache, flushing, low blood pressure, fever, shortness of breath, and dizziness. They often occur during or within 24 hours of the first two infusions and decrease with subsequent doses. Pretreatment with antihistamines, acetaminophen, and steroids reduces their severity [1][2].
Upper respiratory tract infections affect about 40-60% of users, while lower respiratory infections occur in 10-20%. Urinary tract infections are common, seen in 20-30% [1][3].
Serious Side Effects and Risks
Progressive multifocal leukoencephalopathy (PML), a rare brain infection linked to JC virus, has been reported, though cases with Ocrevus are extremely low (less than 1 in 10,000). Risk rises with prior immunosuppressant use [1][2].
Hepatitis B reactivation can lead to liver failure or death in carriers; screening is required before starting [1].
Malignancies, including breast cancer and skin cancers, show higher incidence in trials (0.5-1% vs. placebo). Long-term monitoring is advised [3].
Infusion reactions can be severe or fatal in rare cases, with anaphylaxis possible [2].
Increased infection risk overall, including herpes reactivation and sepsis [1].
Side Effects by Patient Group
In relapsing MS trials, 69.9% experienced adverse events vs. 65.7% on interferon. Discontinuation due to side effects: 1.7% vs. 6.7% [1].
Primary progressive MS: similar profile, with 69.5% adverse events [1].
Rheumatoid arthritis data (from trials) noted higher serious infections [3].
Long-Term Concerns and Management
Depletion of B-cells persists for months after stopping, raising prolonged infection risk. Vaccinations (live or live-attended) are contraindicated during and for 6 months after treatment [2].
Hepatitis B carriers need antiviral prophylaxis [1].
Regular monitoring includes blood tests for infections, liver function, and cancer screening [2].
How Side Effects Compare to Other MS Drugs
Ocrevus has fewer injection-site reactions than interferons but higher infusion risks than oral options like fingolimod. PML risk is lower than with natalizumab [1][3].
[1]: Ocrevus Prescribing Information (FDA)
[2]: Genentech Ocrevus Safety
[3]: Drugs.com Ocrevus Side Effects