Ocrelizumab

Indications

• Relapsing forms of multiple sclerosis (RMS) in adults
• Early primary progressive multiple sclerosis (PPMS) in adults

Dosage

Children: null

Adults: Initially, 300 mg by intravenous infusion, followed by a second dose of 300 mg after 2 weeks. For maintenance, administer 600 mg every 6 months, with the first maintenance dose given 6 months after the initial dose. A minimum interval of 5 months should be maintained between each maintenance dose.

Mechanism of action

Ocrelizumab binds to the CD20 antigen on B lymphocytes, leading to B cell depletion through mechanisms such as antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and apoptosis. This reduction in B cells is believed to contribute to the therapeutic effects in autoimmune conditions like multiple sclerosis by decreasing the inflammatory response.

Pharmacodynamics

Ocrelizumab's pharmacodynamics are characterized by its ability to decrease the number of circulating B cells. This depletion helps to reduce the relapses and disease progression in multiple sclerosis. The therapeutic effects are thought to stem from the modulation of B cell function and the resultant reduction in antibody production and inflammatory mediators involved in the pathophysiology of MS.

Pharmacokinetics

Ocrelizumab is administered via intravenous infusion. The drug has a terminal half-life of approximately 26 days post-initial dosing. It achieves steady-state plasma concentrations by the time of the second maintenance dose. The drug is primarily eliminated via the reticuloendothelial system and its clearance is influenced by B cell depletion status and other patient-specific factors.

Contra-indications

• Active hepatitis B infection
• Severe active infections
• Severe immunocompromised status
• History of progressive multifocal leukoencephalopathy (PML)
• Malignancies

Adverse effects

• Catarrh
• Cystitis
• Increased risk of infections
• Infusion-related reactions
• Malignancy
• Progressive multifocal leukoencephalopathy (PML)

Interactions

• Live vaccines should not be administered during treatment
• Monoclonal antibodies may interact with other immunomodulatory therapies

Precautions

• Complete vaccinations at least 6 weeks before treatment initiation
• Monitor for signs of PML
• Consider contraception in women of childbearing potential during treatment and for 12 months after
• Monitor patients for infusion-related reactions and adjust infusion rates accordingly

Pregnancy

Manufacturer advises avoiding use unless the potential benefit outweighs the risk due to limited information available.

Breast-feeding

Manufacturer advises avoiding use as it may be present in breast milk in animal studies.

Storage

Store in a refrigerator (2°C to 8°C). Do not freeze. Protect from light.

Formulations

• {'form': 'Solution for infusion', 'strength': '300 mg/10 ml', 'packaging': 'Vials'}