Rituximab, also known as Rituxan, is a monoclonal antibody that can be used to treat several kinds of cancers like non-Hodgkin lymphoma and chronic lymphocytic leukemia. It can also be combined with other medications to treat certain autoimmune diseases like rheumatoid arthritis (RA) when combined with methotrexate, and granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) when combined with steroids. (Mayo Clinic). Rituximab combines both κ light-chains and γ heavy-chain constants from human components and light and heavy-chain variable domains of 2B8 from mouse components. This means that this -mAb is considered a chimeric monoclonal antibody. (Cartron, et. al. 2004). For this drug to take effect, it must be put directly into the bloodstream. This can be done in a simple procedure called an infusion, also known as intravenous (IV) therapy. For some lymphoma, like follicular lymphoma, a patient would need to have a steady routine of infusions over a certain period. In this case, there would need to be one infusion, every three weeks, for up to 8 cycles. For RA, a patient would need to receive four infusions over the course of a year, typically given every six months. Rituximab can also cause certain side effects that may lead to serious health conditions. Severe mouth and skin reactions like sores, ulcers, blisters, rash, peeling skin, or pustules may occur. Those who have or had hepatitis B (HBV) or are carriers of it may experience a reactivation of HBV which could lead to liver failure. With this risk, it is recommended that those with HBV or carriers of hepatitis B do not take rituximab. (RITUXAN®)
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The National Cancer Institute (NCI) developed and funded the making of rituximab, finding that this drug can be used to target a specific protein that can help in cancer treatments. Rituximab plays an important role in the survival of patients with non-Hodgkins lymphoma (NHL). To be able to have it kill the lymphoma, researchers found that there was a specific protein that could easily be identified in an NHL B cell. Rituximab binds CD20, a surface protein, that is located on mature B cells. It is known to specifically target CD20, which can be found on mature B lymphocytes. The antibody uses three potential mechanisms to destroy the cancerous lymphocytes which include complement-dependent cytotoxicity, stimulation of apoptosis, or antibody-dependent cytotoxicity. Each of these processes results in cell death, but the most common method is antibody-dependent cytotoxicity. This method can be summarized as an immune response in which the Fc receptors of the IgG recognize and kill the B cell lymphocytes by targeting the CD20 that are on the cell surface. (Selewski et.al., 2010). After seeing the success of rituximab in treating cancerous diseases, researchers were curious to see if it could be used to treat certain autoimmune diseases as well. In diseases like rheumatoid arthritis (RA), it can reduce the symptoms and prevent further joint damage. Since rituximab targets B cells by locating the CD20 proteins, it reduces the number of B cells, which can lead to a reduction of inflammation, swelling, pain, and joint damage. This technique is also used in the treatment of granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). (NCI, 2014) & (Verses Arthritis).
Resources:
Rituximab (Intravenous Route) Side Effects – Mayo Clinic. (n.d.). Www.mayoclinic.org. https://www.mayoclinic.org/drugs-supplements/rituximab-intravenous-route/side-effects/drg-20068057?p=1#:~:text=It%20helps%20the%20immune%20system
Cartron, G., WatierH., GolayJ., & Solal-Celigny, P. (2004). From the bench to the bedside: ways to improve rituximab efficacy. Blood, 104(9), 2635–2642. https://doi.org/10.1182/blood-2004-03-1110
RA | RITUXAN® (rituximab) Infusions & Dosing Schedule. (n.d.). Rituxan. https://www.rituxan.com/ra/treatment/dosing.html#:~:text=Rituxan%20must%20be%20given%20directly
Selewski, D. T., Shah, G. V., Mody, R. J., Rajdev, P. A., & Mukherji, S. K. (2010). Rituximab (Rituxan). American Journal of Neuroradiology, 31(7), 1178–1180. https://doi.org/10.3174/ajnr.A2142
Discovery – Development of Rituximab – NCI. (2014, March 7). Www.cancer.gov. https://www.cancer.gov/research/progress/discovery/blood-cancer#:~:text=Rituximab%20binds%20to%20a%20surface
Rituximab. (n.d.). Versus Arthritis. https://versusarthritis.org/about-arthritis/treatments/drugs/rituximab/#:~:text=Rituximab%20works%20by%20lowering%20the
Rituximab. (n.d.). Medscape. https://www.medscape.com/viewarticle/406941_8?form=fpf
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