Rituxan 500mg Injection (rituximab)

Rituxan 500mg injection contains rituximab, a chimeric monoclonal antibody targeting the CD20 antigen on B lymphocytes. By depleting CD20-positive B cells, rituximab 500mg injection treats several B-cell cancers and autoimmune diseases. It is used in non-Hodgkin lymphomas, chronic lymphocytic leukemia (CLL), rheumatoid arthritis, granulomatosis with polyangiitis/microscopic polyangiitis, and pemphigus vulgaris under major reference labels. The 500 mg/50 mL vial is a supply presentation; dosing varies by indication and may be based on body-surface area or fixed doses.

In oncology, rituximab 500mg injection is combined with chemotherapy in CD20-positive B-cell lymphomas such as diffuse large B-cell lymphoma and follicular lymphoma and with systemic therapy in CLL. In autoimmune disease it is used after or with disease-specific therapy, including rheumatoid arthritis after inadequate TNF inhibitor response, GPA/MPA, and pemphigus vulgaris. Screening for hepatitis B is mandatory before treatment because the rituximab 500mg injection can cause severe or fatal HBV reactivation.

Rituximab 500mg injection binds CD20 on pre-B and mature B lymphocytes and triggers complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity, and apoptosis, leading to prolonged B-cell depletion.

GELA DLBCL trial: Adding rituximab 500mg to CHOP improved survival in older patients with diffuse large B-cell lymphoma and established R-CHOP.

PRIMA: Rituximab 500mg injection maintenance prolonged progression-free survival in selected follicular lymphoma patients after induction.

RA trials: Rituximab plus methotrexate improved outcomes in TNF-inhibitor-inadequate-response RA.

Just like any other medication, the Rituxan 500mg injection is also associated with some side effects. Most of the side effects are minor and usually go away within some time. Here are some of the symptoms, including:

Common side effects

• Infusion fever/chills
  
• Nausea
  
• Fatigue
  
• Headache
  
• Infections
  
• Low blood counts
  

Serious side effects

• Severe/fatal infusion reaction
  
• HBV reactivation
  
• Progressive multifocal leukoencephalopathy (PML)
  
• Tumor lysis syndrome
  
• Severe mucocutaneous reactions
  
• Serious infection/cytopenias
  

Important: Dose and regimen must be prescribed by the treating specialist. Vial strength is not necessarily the patient dose. Do not start, stop, split, combine, or substitute treatment based on website information.

If an infusion is missed, contact the treating unit. Do not simply shift the schedule because timing relative to chemotherapy or autoimmune-disease induction matters.

• HBsAg and anti-HBc before therapy
  
• CBC
  
• Infusion vital signs
  
• Infection signs
  
• Immunoglobulins in recurrent-infection risk
  
• Disease-specific response
  
  

• Current rituximab 500mg/50ml Injection prescribing information (Rituxan/MabThera reference). https://www.accessdata.fda.gov/drugsatfda_docs/label/2010/103705s5311lbl.pdf​
  
• Coiffier B, et al. R-CHOP in DLBCL. New England Journal of Medicine. https://www.nejm.org/doi/full/10.1056/NEJMoa011795​
  
• Salles G, et al. PRIMA. Lancet. https://pubmed.ncbi.nlm.nih.gov/21176949/​
  
• Current oncology/rheumatology/vasculitis guidelines. https://rheumatology.org/vasculitis-guideline​
  
• National Library of medicine. Rituximab. https://www.ncbi.nlm.nih.gov/books/NBK564374/​