How it is administered

Rituximab is administered as an intravenous (IV) infusion by a healthcare professional. It is available in single-dose vials containing a clear, colorless to pale yellow solution. The medication must be diluted before infusion and is never given as a rapid injection or IV push.

For Chronic Lymphocytic Leukemia (CLL), the typical dosing schedule is:

• 375 mg/m² IV the day before starting chemotherapy, then 500 mg/m² IV on Day 1 of cycles 2–6 (every 28 days), in combination with fludarabine and cyclophosphamide.

Premedication with acetaminophen and an antihistamine is recommended before each dose to reduce the risk of infusion reactions.

How it works

Rituximab is a monoclonal antibody that specifically targets the CD20 antigen found on the surface of pre-B and mature B-lymphocytes, which are a type of white blood cell involved in certain blood cancers, including Chronic Lymphocytic Leukemia (CLL).

When rituximab binds to CD20, it triggers the destruction of these B-cells through several mechanisms:

• Complement-dependent cytotoxicity (CDC): Activates the immune system to attack and destroy the targeted cells.
• Antibody-dependent cell-mediated cytotoxicity (ADCC): Recruits other immune cells to help eliminate the B-cells.

By depleting abnormal B-cells, rituximab helps control the progression of CLL and other B-cell malignancies. After treatment, B-cell levels typically begin to recover within 6–12 months.

Who Should take it

Rituximab is indicated for adults with Chronic Lymphocytic Leukemia (CLL), both previously untreated and previously treated, in combination with fludarabine and cyclophosphamide (FC).

It is also used for other B-cell cancers, such as non-Hodgkin's lymphoma, and for certain autoimmune diseases. For CLL, rituximab is part of a combination chemotherapy regimen and is not used alone. Your doctor will determine if rituximab is appropriate based on your diagnosis, overall health, and prior treatments.

Who should not take it

Rituximab should not be used in patients who have had a severe allergic reaction (hypersensitivity) to rituximab or any of its components.

It is not recommended for patients with severe, active infections. Patients with active hepatitis B infection or a history of hepatitis B should be carefully evaluated and monitored, as rituximab can cause reactivation of hepatitis B. Vaccination with live virus vaccines is not recommended before or during treatment with rituximab. Always inform your healthcare provider about your medical history before starting rituximab.

Commonly used with

For CLL, rituximab is most commonly used in combination with fludarabine and cyclophosphamide (the FC regimen). In other blood cancers, it may be combined with chemotherapy regimens such as CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) or CVP (cyclophosphamide, vincristine, prednisone).

Rituximab is not typically used as a single agent for CLL.

Commonly tested with

Rituximab has been tested in combination with various chemotherapy regimens, most notably fludarabine and cyclophosphamide (FC) for CLL. It has also been studied with CHOP, CVP, and other regimens in different types of blood cancers.

In clinical trials, rituximab is often compared to chemotherapy alone to evaluate its added benefit.