Continuing Education Activity
Ocrelizumab is a medication used in the management and treatment of primary progressive and relapsing multiple sclerosis. It is in the anti-CD20 monoclonal antibody class of medications. This activity describes the indications, action, and contraindications for ocrelizumab as a valuable agent in multiple sclerosis management. This activity will highlight the mechanism of action, adverse event profile, and other key factors (e.g., administration, contraindications, monitoring, toxicity) pertinent for interprofessional team members in the care of patients with multiple sclerosis.
- Identify the mechanism of action of ocrelizumab.
- Describe the possible adverse effects of ocrelizumab.
- Review the toxicity of ocrelizumab.
- Summarize interprofessional team strategies for improving care coordination and communication to advance ocrelizumab and improve outcomes.
Ocrelizumab is an FDA-approved CD20-directed humanized monoclonal antibody indicated to treat adult patients with primary progressive or relapsing multiple sclerosis; it received approval from the FDA on March 28, 2017.
FDA-approved indications (with clinical trial summaries):
Multiple Sclerosis (MS)
- ORATORIO study: In this double-blinded study, 732 patients were randomly assigned 2 to 1 to either ocrelizumab (two intravenous 300 mg doses given 14 days apart every 24 weeks) or placebo for at least 120 weeks until a prespecified number of disability events occurred. The study's primary endpoint was the percentage of patients with 12-week confirmed disability progression. Ocrelizumab showed a 12-week confirmed disability progression of 32.9%, whereas the placebo arm showed a 39.3% rate (hazard ratio = 0.76, p=0.03).
- OPERA I study: In this double-blinded study, 821 patients were randomly assigned 1 to 1 to either ocrelizumab (two intravenous 300 mg doses given 14 days apart and then a single 600 mg doses every 24 weeks) or interferon beta-1a (subcutaneous 44 microgram dose three times weekly) for 96 weeks with a primary endpoint of annualized relapse rate. Results showed that ocrelizumab has a statistically significantly lower annualized relapse rate at 0.16 vs. interferon beta-1a at 0.29 (46% reduction, p<0.001).
- OPERA II study: In this double-blinded study, 835 patients were randomly assigned 1:1 to either Ocrelizumab(two intravenous 300mg doses given 14 days apart and then a single 600mg dose every 24 weeks) or interferon beta-1a (subcutaneous 44 microgram dose three times weekly) for 96 weeks with a primary endpoint of annualized relapse rate. Results showed that ocrelizumab has a statistically significantly lower annualized relapse rate at 0.16 vs. Interferon beta-1a at 0.29 (47% reduction, p<0.001).
At the time of launch, ocrelizumab had a list price of $65000 annually. It is generally covered by commercial insurance and by Medicare. The manufacturer provides patient payment assistance in the form of a co-pay program and referrals to a patient payment assistance foundation.
Mechanism of Action
Ocrelizumab is a second-generation anti-CD20 recombinant monoclonal antibody with a molecular mass of 145kDa. It is a follow-up to the anti-CD20 monoclonal antibody rituximab but with a humanized IgG1 tail. Humanization of the antibody is expected to reduce antigenicity and improve CD20 binding. CD20 is a phosphoprotein expressed on a broad range of human B-cells. However, it is not present in the early lineage (stem cells and pro-B-cells) or late lineage (plasmablasts and plasma cells). Ocrelizumab binds to CD20 on B-lymphocytes leading to antibody-dependent cellular cytolysis and complement-mediated lysis. While the precise method by which ocrelizumab exerts its effect on multiple sclerosis is unknown, it depletes B-cells which are thought to affect the pathogenesis of multiple sclerosis using cytokine regulation, antigen presentation, autoantibody production.
Ocrelizumab is FDA-approved for intravenous infusion. It is supplied in 300 mg/mL single-dose vials. The initial dose is given as a 300 mg intravenous infusion over 2.5 hours, followed up with an additional 300 mg intravenous infusion 14 days later. Subsequent doses are given every six months as a 600 mg intravenous infusion over 3.5 hours. Maintenance doses of ocrelizumab should be at a minimum of five months apart. Some argue that dosing should not be on a fixed schedule but based on CD19/20 counts to optimize dosing to minimize unnecessary patient exposure and allow for significant cost savings. For mild to moderate adverse events, a reduction in infusion rate is indicated if tolerated. Severe and life-threatening reactions indicate interruption or discontinuation of the drug.
Adverse reactions in relapsing multiple sclerosis with an incidence of more than 5% and higher than interferon beta-1a:
- Back pain
- Herpes virus-associated infections
- Infusion reactions
- Lower respiratory infections
- Pain in extremities
- Upper respiratory infections
Adverse reactions in primary progressive multiple sclerosis with an incidence of more the 5% and higher than placebo:
- Edema peripheral
- Herpes virus-associated infections
- Infusion reactions
- Lower respiratory tract infections
- Skin reactions
- Upper respiratory tract infections
Ocrelizumab is contraindicated in the following patients:
- Those with a history of life-threatening infusion reactions to ocrelizumab
- Patients with active hepatitis-B infection
Before initiating ocrelizumab:
- Hepatitis B virus screening is necessary. There have been reports of ocrelizumab leading to reactivation of latent HBV in a previously resolved patient.
- All necessary immunizations should be given at least six weeks before initiating ocrelizumab, given the expected B-cell depletion.
- Consider previous immunosuppressive therapy for potential increased immunosuppressive effects.
Before every ocrelizumab infusion:
- Determine if there is an active infection; if yes, delay infusion until resolution
- Premedicate with 100 mg of methylprednisolone and an antihistamine 30 minutes before infusion
- Consider premedication with an antipyretic
- A regiment of cetirizine (10 mg), ranitidine (75 mg), increased hydration, IV diphenhydramine (50 mg), IV methylprednisolone (125 mg), and oral acetaminophen (650 mg) has been shown to reduce infusion reactions by 60% in one study.
Before initiating ocrelizumab therapy, hepatitis B virus screening is indicated.
Patients receiving an ocrelizumab infusion will require monitoring for at least the next hour for the following signs and symptoms of refusion reactions:
- Coughing or wheezing
- Fast heart rate
- Feeling faint
- Itchy skin
- Shortness of breath
- Swelling of throat
- Throat irritation or pain
- Trouble breathing
In clinical trials, there was an incidence of life-threatening bronchospasm (which recovered with treatment) with the initial infusion of ocrelizumab.
Enhancing Healthcare Team Outcomes
Ocrelizumab is a new biological agent, and even though it has shown a positive risk/benefit trade-off in clinical trials, it does require close monitoring for safety; thus, besides the prescribing clinician, both nurses and pharmacists are responsible for educating the patient on the potential side effects of the drug.
During IV administration, the drug has shown infusion reactions in more than one-third of patients; therefore, it is essential to monitor side effects such as coughing, dizziness, fast heart rate, fatigue, feeling faint, fever, flushing, headache, hives, itchy skin, nausea, rash, shortness of breath, swelling of the throat, throat irritation or pain, tiredness, trouble breathing and wheezing. In clinical trials, there was an incidence of life-threatening bronchospasm (which recovered with treatment) during the initial infusion of ocrelizumab. Therefore, because the drug can trigger a life-threatening infusion reaction, the interprofessional team needs to have the necessary medications and equipment in the room to ensure safe outcomes.
Since some adverse effects are delayed-onset, including opportunistic infections and malignancies, an outpatient neurology nurse should continue to follow the patients and coordinate additional surveillance between infusions. The nurses and pharmacists should regularly check immune titers to monitor immunosuppression. While there are no reported cases of progressive multifocal leukoencephalopathy (PML) to date (which has happened in other anti-CD20 antibodies and immunosuppressant therapies), the entire healthcare team must be on the lookout for clinical signs and symptoms, including hemiparesis, clumsiness, visual changes, memory/thinking changes, and personality changes. The clinical trial experience showed a higher rate of breast malignancy in the ocrelizumab-treated group. However, patients are not advised to undergo increased surveillance and continue to undergo routine breast cancer screening as age-appropriate.
Pharmacists should also work with the prescriber and nursing to ensure proper dosing, preclude drug interactions, and educate the patient and nursing staff on potential adverse reactions. This information will allow nursing to administer the drug effectively and monitor for any adverse reactions and inform the ordering clinician should they encounter any concerns. This collaborative paradigm exemplifies the kind of interprofessional teamwork the healthcare team requires to administer ocrelizumab effectively to achieve optimal patient outcomes while minimizing patient risks. [Level 5]
Finally, the drug is prohibitively expensive, and insurance health plans do not always cover the cost. Without long-term data available, clinicians should always consider other similar cost-effective agents first.
Interprofessional communication between the primary treatment team and the patient’s primary care provider essential to make sure such screenings occur as estimates are that roughly one-third of women do not get an appropriate annual screening.