How long does it take for Rituxan to work?
Rituxan (rituximab) is a monoclonal antibody therapy that targets CD20, a protein found on B-cells, a type of white blood cell involved in the immune response. It is used to treat:
- Non-Hodgkin’s lymphoma (NHL) and chronic lymphocytic leukemia (CLL) – blood cancers affecting B-cells
- Mature B-cell NHL and mature B-cell acute leukemia
- Autoimmune disorders like rheumatoid arthritis (RA) – where B-cells mistakenly attack the body’s own tissues
Rituxan is administered via intravenous (IV) infusion and works by depleting B-cells, reducing cancer growth and autoimmune activity.
How Fast Does Rituxan Work for Non-Hodgkin’s Lymphoma and Chronic Lymphocytic Leukemia?
Rituxan starts working quickly in patients with NHL and CLL:
- Within 24–72 hours: CD20+ B-cells in the bloodstream are rapidly depleted.
- Within 2 weeks: Rituxan binds to tumor cells and reduces B-cell numbers in tumor biopsies.
- Within 3 weeks: Further reduction of B-cells is confirmed.
When will cancer symptoms improve?
In addition to these immediate effects of Rituxan on the body, researchers have investigated how long it takes for the drug to cause signs of cancer to decrease and disappear.
- In a clinical trial with 166 NHL patients, 48% of patients responded to Rituxan, with a median time to response of 50 days (about 7 weeks).
Rituxan also works in the same way to cause a rapid depletion of B-cells in patients with CLL.
Your doctor will monitor your progress and check for side effects.
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How Fast Does Rituxan Work for Rheumatoid Arthritis?
Rituxan also depletes B-cells quickly in RA patients, but symptom relief takes longer. One dose of Rituxan is enough to deplete a patient’s B-cells.
- First effects within 8 weeks: Some patients notice early symptom relief due to glucocorticoid pre-medication, not Rituxan itself.
- Noticeable improvement by 16 weeks: Most patients experience reduced pain and inflammation by this time.
- Slower than other biologic DMARDs: Rituxan has a delayed onset compared to other disease-modifying anti-rheumatic drugs (DMARDs).
Your healthcare provider will assess your response to Rituxan and adjust your treatment plan as needed.
References
- Maloney DG, Liles TM, Czerwinski DK, et al. Phase I clinical trial using escalating single-dose infusion of chimeric anti-CD20 monoclonal antibody (IDEC-C2B8) in patients with recurrent B-cell lymphoma. Blood. 1994 Oct 15;84(8):2457-66.
- Maloney DG, Grillo-Lopez AJ, White CS, et al. IDEC-C2B8 (Rituximab) anti-CD20 monoclonal antibody therapy in patients with relapsed low-grade non-Hodgkin's lymphoma. Blood. 1997 Sep 15;90(6):2188-95.
- DailyMed. Rituxan. Highlights of Prescribing Information. [Accessed March 7, 2025]. Available online at: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b172773b-3905-4a1c-ad95-bab4b6126563
- Bryan J, Borthakur G. Role of rituximab in first-line treatment of chronic lymphocytic leukemia. Ther Clin Risk Manag. 2011; 7: 1–11. doi: 10.2147/TCRM.S5855.
- Hainsworth JD. Safety of rituximab in the treatment of B cell malignancies: implications for rheumatoid arthritis. Arthritis Res Ther. 2003; 5(Suppl 4): S12–S16. doi: 10.1186/ar1008.
- Randall KL. Rituximab in autoimmune diseases. Aust Prescr. 2016 Aug; 39(4): 131–134. doi: 10.18773/austprescr.2016.053.
- Buch MH, Smolen JS, Betteridge N, et al. Updated consensus statement on the use of rituximab in patients with rheumatoid arthritis. Annals of the Rheumatic Diseases 2011;70:909-920.
Read next
What are biosimilar drugs and how do they compare to biologics?
A biosimilar is a biological product that is similar to a reference biologic (usually the originally approved product) and for which there are no clinically meaningful differences in terms of safety, purity, and potency. The most recently approved biosimilar is Starjemza (ustekinumab-hmny), an interchangeable biosimilar to Stelara, cleared by the FDA on May 22, 2025.
Continue reading
Does Rituxan cause hair loss?
It’s possible for Rituxan (rituximab) to cause hair loss. This includes losing hair anywhere on your body, such as your head, legs, eyebrows, and eyelashes. Hair loss (alopecia) does not seem to be a common side effect of Rituxan. Continue reading
How does the drug Rituxan work?
Rituxan (rituximab) is a monoclonal antibody that targets the CD20 protein found on the surface of B-cells, a type of white blood cell involved in immune responses. By binding to CD20, Rituxan helps eliminate these cells, which is beneficial in treating certain cancers and autoimmune disorders. Continue reading
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Drug information
- Rituxan Information for Consumers
- Rituxan prescribing info & package insert (for Health Professionals)
- Side Effects of Rituxan (detailed)
- Rituxan user reviews (53)
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