How it is administered

Rituximab is administered as an intravenous (IV) infusion by a healthcare professional in a clinical setting. It is available in single-dose vials that are diluted and infused into a vein over several hours. The dosing schedule and number of infusions depend on the specific type of blood cancer being treated and the treatment protocol. For some conditions, rituximab may also be given as a subcutaneous injection (under the skin), but this is typically after at least one successful IV infusion.

For pediatric patients with mature B-cell acute lymphoblastic leukemia (B-ALL), rituximab is given in combination with chemotherapy according to a specific schedule. Premedication with acetaminophen and an antihistamine is recommended before each infusion to reduce the risk of infusion-related 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 some types of acute lymphoblastic leukemia (ALL).

When rituximab binds to the CD20 antigen on these cells, it triggers the immune system to attack and destroy the cancerous B cells. This process can occur through several mechanisms, including complement-dependent cytotoxicity (CDC), where the body's complement system helps destroy the cell, and antibody-dependent cell-mediated cytotoxicity (ADCC), where immune cells are recruited to kill the targeted B cells.

By reducing the number of abnormal B cells, rituximab helps control the progression of blood cancers. In pediatric patients with mature B-cell ALL, rituximab is used in combination with chemotherapy to improve treatment outcomes. After treatment, normal B cells typically recover over several months.

Who Should take it

Rituximab is indicated for adult and pediatric patients (aged 6 months and older) with certain types of blood cancers, including:

• Non-Hodgkin's lymphoma (NHL)
• Chronic lymphocytic leukemia (CLL)
• Pediatric patients with previously untreated, advanced stage, CD20-positive diffuse large B-cell lymphoma (DLBCL), Burkitt lymphoma (BL), Burkitt-like lymphoma (BLL), or mature B-cell acute leukemia (B-AL), in combination with chemotherapy

For acute lymphoblastic leukemia, rituximab is specifically used in pediatric patients with mature B-cell ALL (a subset of ALL that expresses CD20 on the surface of the cancer cells), as part of a combination chemotherapy regimen.

Your doctor will determine if rituximab is appropriate for you or your child based on the type of leukemia, the presence of the CD20 marker, and other health factors.

Who should not take it

Rituximab should not be used in patients who have had a severe allergic reaction (anaphylaxis) to rituximab or any of its components. There are no other absolute contraindications listed in the FDA label.

However, caution is advised in patients with active, severe infections, as rituximab can further suppress the immune system and increase the risk of serious infections. Patients should also be screened for hepatitis B virus (HBV) infection before starting treatment, as rituximab can cause reactivation of HBV, which can be life-threatening.

Live virus vaccines should not be given before or during rituximab treatment. Rituximab can cause harm to an unborn baby, so it is not recommended during pregnancy unless the potential benefit outweighs the risk. Women of childbearing potential should use effective contraception during treatment and for 12 months after the last dose.

Commonly used with

Rituximab is most commonly used in combination with chemotherapy regimens. For pediatric mature B-cell ALL, it is combined with intensive chemotherapy protocols such as LMB (Lymphome Malin B) chemotherapy, which includes drugs like cyclophosphamide, vincristine, prednisone, doxorubicin, methotrexate, cytarabine, and etoposide.

In other blood cancers, rituximab may be combined with regimens such as CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) or CVP (cyclophosphamide, vincristine, prednisone).

Commonly tested with

Rituximab has been tested in combination with various chemotherapy regimens in clinical trials for blood cancers, including:

• LMB chemotherapy for pediatric mature B-cell ALL and lymphoma
• CHOP or CVP chemotherapy for adult lymphomas
• Fludarabine and cyclophosphamide (FC) for chronic lymphocytic leukemia (CLL)

These combinations have been shown to improve outcomes compared to chemotherapy alone in patients with CD20-positive blood cancers.