From the Guidelines
Rituximab is a monoclonal antibody medication that targets and destroys B cells with the CD20 protein, primarily used to treat non-Hodgkin lymphoma, chronic lymphocytic leukemia, and autoimmune disorders, with a common dosing regimen of 375 mg/m² once weekly for four weeks.
Key Points
- Rituximab works by binding to CD20 on the surface of B cells, facilitating their destruction 1.
- It is commonly prescribed for non-Hodgkin lymphoma, chronic lymphocytic leukemia, rheumatoid arthritis, granulomatosis with polyangiitis, and other autoimmune conditions.
- The medication is typically administered intravenously in a hospital or clinic setting, with dosing regimens varying by condition.
- Patients should be aware that rituximab suppresses the immune system, increasing infection risk, and may take several months to show full therapeutic effect.
- Regular blood tests are necessary to monitor blood cell counts during treatment.
Administration and Monitoring
- For lymphoma, a common regimen is 375 mg/m² once weekly for four weeks, while for rheumatoid arthritis, it's often given as two 1000 mg infusions separated by two weeks.
- The first infusion is usually given slowly to monitor for infusion reactions, which can include fever, chills, and breathing difficulties.
- Rituximab has been associated with rare but potentially fatal complications, including severe mucocutaneous reactions, reactivation of hepatitis B, and multifocal leukoencephalopathy 1.
Special Considerations
- Patients with hepatitis B are at high risk of reactivation when treated with rituximab, and screening and anti-viral prophylaxis are recommended 1.
- Rituximab may also increase the risk of neutropenia and infection, particularly in patients who have previously or concurrently received cytotoxic chemotherapy 1.
From the FDA Drug Label
Rituximab is a genetically engineered chimeric murine/human monoclonal IgG1 kappa antibody directed against the CD20 antigen. Rituximab has an approximate molecular weight of 145 kD. Rituximab is produced by mammalian cell (Chinese Hamster Ovary) suspension culture in a nutrient medium that may contain the antibiotic gentamicin. Gentamicin is not detectable in the final product. RITUXAN (rituximab) injection is a sterile, preservative-free, clear, colorless solution for intravenous infusion. RITUXAN is supplied at a concentration of 10 mg/mL in either 100 mg/10 mL or 500 mg/50 mL single-dose vials. Each mL of solution contains 10 mg rituximab, polysorbate 80 (0.7 mg), sodium chloride (9 mg), sodium citrate dihydrate (7.35 mg), and Water for Injection, USP. The pH is 6.5.
Rituximab (Rituxan) is a monoclonal antibody that targets the CD20 antigen expressed on the surface of pre-B and mature B-lymphocytes. It is used to treat various conditions, including:
- Non-Hodgkin's Lymphoma (NHL)
- Chronic Lymphocytic Leukemia (CLL)
- Rheumatoid Arthritis (RA)
- Granulomatosis with Polyangiitis (GPA)
- Microscopic Polyangiitis (MPA)
- Pemphigus Vulgaris (PV)
It works by depleting B-cells, which are believed to play a role in the pathogenesis of these conditions 2.
From the Research
Definition and Mechanism of Action
- Rituximab is an anti-CD20 monoclonal antibody that targets the CD20 antigen found on the surface of malignant and normal B lymphocytes 3.
- It induces lysis and apoptosis of normal and malignant human B cells, and sensitises malignant B cells to the cytotoxic effect of chemotherapy 4.
- The cytotoxic effects of rituximab on CD20-positive malignant B cells appear to involve complement-dependent cytotoxicity, complement-dependent cellular cytotoxicity, antibody-dependent cellular cytotoxicity, and induction of apoptosis 3.
Clinical Uses
- Rituximab is used for the treatment of non-Hodgkin's lymphoma (NHL), chronic lymphocytic leukemia (CLL), and autoimmune diseases 3, 5, 6.
- It is approved for the treatment of patients with low-grade or follicular, relapsed or refractory, CD20-positive B-cell NHL, and for use in combination with CHOP chemotherapy for the treatment of diffuse large B-cell lymphoma 3.
- Rituximab is also used for the treatment of CLL, particularly in combination with chemotherapy such as fludarabine or fludarabine and cyclophosphamide (R-FC regimen) 5, 7.
Efficacy and Safety
- Rituximab has been shown to be effective in achieving objective response rates in patients with indolent and aggressive forms of B-cell NHL, as well as in patients with CLL 3, 5, 7.
- The combination of rituximab with chemotherapy has been shown to be more effective than chemotherapy alone in providing tumor remission and patient survival in patients with NHL and CLL 3, 4.
- Rituximab is generally well tolerated, with infusion-related reactions being the most common adverse effect 3, 4.
- Serious and severe side effects are rare, but systemic infection remains a major concern and may result in death 6.