Rituximab
A chimeric anti-CD20 antibody used for B-cell lymphomas, chronic lymphocytic leukemia, rheumatoid arthritis and ANCA vasculitis.
Drug card
- How it works
- Binding CD20 on B lymphocytes so that the B cells are destroyed
- Used for
- CD20-positive B-cell non-Hodgkin lymphoma
- Chronic lymphocytic leukemia
- Rheumatoid arthritis, after a TNF inhibitor fails
- ANCA vasculitis (GPA and microscopic polyangiitis)
- Known for
- Infusion reactions, worst with the first infusion
- Hepatitis B reactivation
- JC virus brain infection (PML)
- Its name
- -mab means a monoclonal antibody; -ximab means a chimeric monoclonal antibody
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does rituximab work?
Rituximab is a chimeric mouse-human IgG1 antibody that binds CD20 on pre-B and mature B lymphocytes, normal or malignant. The bound cells are lysed by complement (CDC) and by immune effector cells (ADCC), depleting B cells. In rheumatoid arthritis it removes B cells thought to drive the disease by making rheumatoid factor and other autoantibodies and by presenting antigen.
Uses
What is rituximab used for?
- CD20-positive B-cell non-Hodgkin lymphoma
- Chronic lymphocytic leukemia
- Rheumatoid arthritis, after a TNF inhibitor fails
- ANCA vasculitis (GPA and microscopic polyangiitis)
- Pemphigus vulgaris
Side effects
Side effects of rituximab
- Infusion reactions, worst with the first infusionKnown forSerious
- Hepatitis B reactivationKnown forSerious
- JC virus brain infection (PML)Known forSerious
- Severe skin and mouth reactions (SJS, TEN)Serious
- Tumor lysis syndromeSerious
- Serious bacterial, fungal and viral infectionsSerious
- Low blood counts (neutropenia, lymphopenia)Serious
- Heart rhythm problems during infusionSerious
- Kidney damageSerious
- Bowel obstruction or perforationSerious
- Swelling of face or throat (angioedema) on infusionSerious
- Bronchospasm during infusionSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Hepatitis B (HBsAg and anti-HBc) is tested for before starting, and carriers are monitored for reactivation during and after treatment.
- Premedication with an antihistamine and paracetamol (plus a glucocorticoid outside cancer) comes before each infusion.
- Many circulating cancer cells raise the risk of tumor lysis syndrome, so hydration and drugs that lower uric acid are given.
- Live vaccines are not given before or during treatment.
Good to know: Obinutuzumab is a newer, humanized anti-CD20 antibody engineered to trigger stronger ADCC.
Remember it
A way to remember it
Wipe out the B cells, check for hepatitis B
Anti-CD20 antibodies deplete B cells, and one of their boxed warnings is hepatitis B reactivation, so every patient is tested for hepatitis B before the first dose.
Written for biofideX
Its name
-mab means monoclonal antibody
Older names show the source: -ximab chimeric, -zumab humanized, -umab human. WHO stopped adding that part in 2017 and dropped -mab in 2021; new names end in -tug, -bart, -ment or -mig.
-ximab means chimeric monoclonal antibody
Chimeric antibodies join mouse variable regions to human constant regions, as in rituximab (against CD20) and infliximab (against TNF). WHO stopped adding this part to names in 2017.
- Every drug name stem
Its class
CD20-targeted antibodies
CD20 is a surface protein on B lymphocytes, from the pre-B stage to mature B cells, and on B-cell lymphomas and leukemias. These antibodies bind CD20 and get the cell killed by complement (complement-dependent cytotoxicity), by immune effector cells (ADCC) and by apoptosis, depleting B cells. That treats B-cell cancers and damps autoimmune diseases in which B cells and their autoantibodies play a part.
Easily mixed up with HER2-targeted antibodies, TNF inhibitors and PD-1 checkpoint inhibitors.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Rituximab-abbs injection: label (DailyMed)
- Rituximab (NCI Thesaurus)
- Rituximab (NCI)
- Obinutuzumab (NCI Thesaurus)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Targeted therapy and the immune system
Rituximab is one of 13 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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