Ocrelizumab

Relapsing Forms of Multiple Sclerosis

Ocrelizumab is used to treat adults with relapsing forms of multiple sclerosis (MS). This category includes several specific types of the disease:

• Clinically isolated syndrome: This refers to the first episode of neurologic symptoms that may lead to an MS diagnosis.
• Relapsing-remitting disease: This is characterized by clearly defined attacks of new or increasing neurologic symptoms, followed by periods of partial or complete recovery.
• Active secondary progressive disease: This occurs when the disease begins to worsen more steadily following an initial relapsing-remitting course, while still showing signs of active relapses or new activity on imaging.

Primary Progressive Multiple Sclerosis

Ocrelizumab is also approved for the treatment of primary progressive multiple sclerosis (PPMS) in adults. PPMS is a form of the disease where symptoms and physical disability gradually worsen from the beginning, typically without distinct relapses or periods of remission.

The goal of treatment with ocrelizumab is to reduce the frequency of clinical relapses and slow the progression of physical disability associated with the disease.

Mechanism of Action

Ocrelizumab is a humanized monoclonal antibody. It is designed to target and bind to a specific protein called CD20, which is found on the surface of B cells, a type of white blood cell in the immune system.

In multiple sclerosis (MS), the immune system mistakenly attacks the protective coating (myelin) that surrounds nerves in the brain and spinal cord. B cells are believed to play a significant role in this immune response and the resulting nerve damage. By binding to the CD20 protein, ocrelizumab causes these specific B cells to be depleted or removed from the body.

By reducing the number of these B cells, the medication helps to:

• Reduce inflammation: Lowering the immune system's activity in the central nervous system.
• Prevent nerve damage: Limiting the attacks on the myelin sheath that covers nerve fibers.
• Slow disease progression: Decreasing the frequency of relapses and the worsening of physical disability.

While the exact way ocrelizumab works to treat MS is not fully understood, its primary effect is the targeted reduction of B cells involved in the disease process.

Common Side Effects

Many people experience infusion-related reactions during or shortly after receiving ocrelizumab. Other common side effects include:

• Upper respiratory tract infections, such as the common cold or sinus infections
• Skin infections
• Lower respiratory tract infections
• Headache
• Tiredness

Serious Side Effects

Ocrelizumab can cause serious side effects that require immediate medical attention. These include:

• Infusion Reactions: Severe reactions can occur during the infusion or up to 24 hours later. Symptoms may include fever, chills, dizziness, wheezing, nausea, or swelling of the face and tongue.
• Infections: There is an increased risk of serious infections, including the reactivation of hepatitis B or a rare brain infection called progressive multifocal leukoencephalopathy (PML). Symptoms of PML may include weakness on one side of the body, vision changes, or confusion.
• Cancer Risk: An increased risk of certain types of cancer, including breast cancer, has been reported in clinical studies.
• Immune-Mediated Colitis: This is an inflammation of the colon that can cause severe diarrhea, stomach pain, or bloody stools.
• Severe Skin Reactions: Rare but serious skin conditions involving blistering, peeling, or sores in the mouth or nose may occur.

Infusion Reactions

Infusion-related reactions are common and can be severe. These typically occur during or within 24 hours of the infusion. Symptoms may include itchy skin, rash, hives, tiredness, coughing, wheezing, shortness of breath, throat irritation, flushing, fast heartbeat, fever, headache, dizziness, or nausea. Healthcare providers usually administer medications such as corticosteroids and antihistamines before the infusion to reduce this risk and monitor patients closely during and after the procedure.

Infections

Ocrelizumab affects the immune system, which may increase the risk of developing infections or worsening existing ones. Serious concerns include:

• Progressive Multifocal Leukoencephalopathy (PML): A rare but serious brain infection caused by the JC virus that can lead to disability or death.
• Hepatitis B Virus (HBV) Reactivation: If a person has had hepatitis B in the past, the virus can become active again. Screening for HBV is required before starting treatment.
• Herpes Infections: An increased risk of shingles (herpes zoster) and cold sores (herpes simplex) has been observed.
• Respiratory and Skin Infections: Common infections include the flu, upper respiratory tract infections, and skin infections.

Malignancies

There may be an increased risk of certain cancers, including breast cancer, associated with this medication. Patients are encouraged to follow standard breast cancer screening guidelines while receiving treatment.

Vaccinations

Live or live-attenuated vaccines should not be administered during treatment and should be completed at least four weeks before starting ocrelizumab. Non-live vaccines should be completed at least two weeks before starting the medication.

Contraindications

This medication is not used in individuals with an active hepatitis B infection or those who have a history of life-threatening infusion reactions to ocrelizumab.

Pregnancy

Ocrelizumab may cause harm to an unborn baby. If you are able to become pregnant, your healthcare provider may perform a pregnancy test before you begin treatment to confirm you are not pregnant.

It is important to use effective birth control during treatment and for at least 6 months after your last dose of ocrelizumab. If you become pregnant during this time, you should contact your healthcare provider immediately.

A pregnancy registry exists to monitor the health of individuals who use ocrelizumab during pregnancy and the health of their babies. This information helps researchers understand the drug's impact on pregnancy outcomes.

Infants who were exposed to ocrelizumab while in the womb may have a temporary reduction in B-cells, which are a type of white blood cell that helps the immune system. Because of this, it is necessary to discuss your infant's vaccination schedule with a doctor, as certain live vaccines may need to be delayed until the child's immune system recovers.

Breastfeeding

It is not known if ocrelizumab passes into breast milk or if it could affect a nursing infant. You should talk to your healthcare provider about the risks and benefits of breastfeeding while receiving this medication.

Dosage Forms

Ocrelizumab is supplied in the following form:

• Intravenous Solution: A sterile, preservative-free liquid provided in single-dose vials for infusion into a vein.

The solution is concentrated and must be diluted by a healthcare provider before use. It typically appears clear to slightly opalescent and may be colorless to pale brown.

FDA Approval and Indications

Ocrelizumab is approved by the U.S. Food and Drug Administration (FDA) for the treatment of adults with relapsing forms of multiple sclerosis (MS), which includes clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease. It is also approved for the treatment of primary progressive multiple sclerosis (PPMS).

Regulatory Safety Communications

The FDA continuously monitors the safety profile of ocrelizumab. In 2020, the FDA investigated a potential safety signal regarding breast cancer based on reports in the FDA Adverse Event Reporting System (FAERS). Following an evaluation of the available data, the FDA concluded that no regulatory action was required at that time.

Prescribing Requirements

The FDA requires specific screening and monitoring for patients prescribed ocrelizumab. Healthcare providers must screen patients for hepatitis B virus (HBV) infection prior to the first dose, as the medication can lead to virus reactivation. Additionally, the drug must be administered in a clinical setting equipped to manage serious infusion-related reactions.

Factors Influencing Cost

The total cost of ocrelizumab treatment is influenced by several variables. Because it is a biologic medication administered by a healthcare professional, the price includes both the drug itself and the services required to provide the infusion.

• Insurance Coverage: Out-of-pocket expenses depend on the specific terms of a health insurance plan, including deductibles and coinsurance rates.
• Facility Fees: Costs can vary depending on whether the infusion is received at a hospital, a specialized infusion center, or a doctor's office.
• Generic Status: There is currently no generic or biosimilar version of ocrelizumab available. Biologic medications typically maintain higher costs until biosimilar alternatives enter the market.

Financial Assistance

Patients may be able to reduce their out-of-pocket costs through manufacturer-sponsored programs. These may include copay assistance for those with private insurance or support programs for patients who are uninsured or meet specific financial need criteria. It is recommended to consult with a healthcare provider or insurance coordinator to understand specific coverage details and available support.