Rituximab

Class

• • Anti-CD20 chimeric monoclonal

Indications

• lymphomas

• leukemias

• transplant rejection

• some autoimmune disorders

Administration/Absorption

Dosage

Distribution

Mechanism

• Destroys both normal and malignant B cells that have CD20 on their surfaces

• binds to the cluster of differentiation 20 (CD20) molecule

  • widely expressed on B cells, from early pre-B cells to later in differentiation

  • absent on terminally differentiated plasma cells

  • Function unknown

    • may play a role in Ca²⁺ influx across plasma membranes

    • maintaining intracellular Ca²⁺ concentration and allowing activation of B cells

  • Effects:

    • Fc portion => antibody-dependent cellular cytotoxicity (ADCC) / complement-dependent cytotoxicity (CDC).

    • General regulatory effect on the cell cycle.

    • Increases MHC II and adhesion molecules LFA-1 and LFA-3 (lymphocyte function-associated antigen).

    • Elicits shedding of CD23.

    • Downregulates the B cell receptor.

    • Induces apoptosis of CD20+ cells.

• Affects and entirely depletes peripheral B cells

• Only depletes 60-70% of B cells within in the lymphatics system

• Rarely affects those present in the bone marrow.

Excretion

Side effects

• • Severe infusion reactions

• Cardiac arrest

  • Tumor lysis syndrome, causing acute renal failure

  • Infections

  • Hepatitis B reactivation

  • Other viral infections

  • Progressive multifocal leukoencephalopathy (PML)

  • Immune toxicity, with depletion of B cells in 70% to 80% of lymphoma patients

  • Pulmonary toxicity

Interactions

Contraindications