How it is administered

Rituximab is given as an intravenous (IV) infusion, meaning it is administered directly into a vein by a healthcare professional in a clinic or hospital setting. The dose and schedule depend on the specific blood cancer being treated, such as Non-Hodgkin's Lymphoma (NHL), Chronic Lymphocytic Leukemia (CLL), or other indications. For some conditions, rituximab may also be given in combination with chemotherapy.

For pediatric patients with certain types of lymphoma or leukemia, the dosing and schedule are adjusted based on body surface area and chemotherapy regimen. Premedication with acetaminophen and an antihistamine is recommended before each infusion to help reduce the risk of infusion-related reactions.

How it works

Rituximab is a monoclonal antibody that targets a protein called CD20, which is found on the surface of certain B-cells (a type of white blood cell involved in many blood cancers). By binding to CD20, rituximab helps the immune system recognize and destroy these B-cells.

The destruction of B-cells occurs through several mechanisms, including complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC). This means that rituximab not only directly marks the cancerous B-cells for destruction but also recruits other parts of the immune system to help eliminate them. Over time, this leads to a reduction in the number of abnormal B-cells, which can help control or eliminate certain blood cancers.

After treatment, B-cell levels in the blood typically decrease and may remain low for several months. Eventually, healthy B-cells usually recover, but this can take 6 to 12 months or longer in some patients.

Who Should take it

Rituximab is used to treat adults and some children with certain blood cancers, including:

• Non-Hodgkin's Lymphoma (NHL): For relapsed or refractory, low-grade or follicular, CD20-positive B-cell NHL as a single agent; in combination with chemotherapy for previously untreated follicular or diffuse large B-cell lymphoma (DLBCL); and as maintenance therapy after initial treatment.
• Chronic Lymphocytic Leukemia (CLL): In combination with chemotherapy (fludarabine and cyclophosphamide) for previously untreated or previously treated CD20-positive CLL.
• Pediatric patients (aged 6 months and older): For previously untreated, advanced stage, CD20-positive DLBCL, Burkitt lymphoma, Burkitt-like lymphoma, or mature B-cell acute leukemia in combination with chemotherapy.

Rituximab may also be used for other autoimmune conditions, but for blood cancers, it is primarily indicated for the above conditions.

Who should not take it

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

Caution should be used in patients with active, severe infections, as rituximab can further suppress the immune system. It is not recommended for use in patients with severe, active infections.

Patients with hepatitis B infection (current or past) should be carefully screened and monitored, as rituximab can cause reactivation of hepatitis B, which may be life-threatening. Rituximab should be used with caution in pregnant women, as it can harm the fetus, and in breastfeeding women, as it is not recommended to breastfeed during treatment and for 6 months after the last dose.

Live virus vaccines should not be given before or during rituximab treatment.

Commonly used with

Rituximab is often used in combination with chemotherapy regimens, such as:

• CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) for DLBCL
• CVP (cyclophosphamide, vincristine, prednisone) for follicular lymphoma
• Fludarabine and cyclophosphamide (FC) for CLL

It may also be used with other supportive medications, such as acetaminophen, antihistamines, and corticosteroids, to reduce infusion reactions and manage side effects.

Commonly tested with

Rituximab has been tested in clinical trials with various chemotherapy agents, including CHOP, CVP, fludarabine, cyclophosphamide, and bendamustine. It has also been studied in combination with other targeted therapies and as maintenance therapy after initial chemotherapy.

In pediatric studies, rituximab has been combined with LMB chemotherapy regimens for advanced stage B-cell lymphomas and leukemias.