Rituximab


Truxima - biosimilar

FDA Approved uses

  • Pemphigus vulgaris
  • ANCA vasculitis
  • Rheumatoid arthritis
  • Lymphoma


Off label uses

  • APL syndrome
  • Cryoglobulinemia
  • Lupus
  • ITP
  • Autoimmune hemolytic anemia

Is Rituximab more effective in seropositive RA than seronegative?

Is Rituximab a risk for severe Covid infection?
Are infusion reactions the same as allergic reactions and do they preclude using it? Most infusion reactions occur with the first dose. Most occur after the first or second dose but 10 and 30 percent occur during subsequent treatments so in general, the likelihood of an infusion reaction declines with each subsequent course of therapy. The majority of reactions are mild and not life threatening, serious reactions can occur and may be fatal. [1]

Of all monoclonal ab reactions, the incidence of an infusion reaction during the first drug administration  is highest for rituximab (both intravenous and subcutaneous) and alemtuzumab (≥50 percent each). 


Signs and symptoms of infusion reaction

Intravenous infusion reactions may affect any organ system in the body. Most are mild in severity, although severe and even fatal reactions occur. The most common signs and symptoms of infusion reactions are: 

  • Fever and/or shaking chills
  • Flushing and/or itching
  • Alterations in heart rate and blood pressure
  • Dyspnea or chest discomfort
  • Back or abdominal pain
  • Nausea, vomiting, and/or diarrhea
  • Various types of skin rashes 

 Proposed mechanisms of infusion reaction

The exact mechanism responsible for infusion reactions caused by any of the MoAbs is unclear, although understanding of the pathophysiology is an area of active research. Several different types of reactions to MoAbs have been identified, which may have overlapping clinical features and pathophysiology. 


Antigen-ab reaction

Most reactions appear to be the result of antibody-antigen interactions resulting in cytokine release. The most predictable reaction occurs with rituximab and is thought to be caused by the interaction of the drug with the target antigen (CD20) on circulating lymphocytes, followed by cytokine release from these cells as they are destroyed. Evidence for this mechanism includes the observation that severe and fatal reactions have typically occurred in patients with high numbers of circulating lymphocytes bearing the target antigen. 

Type 1 hypersensitvity reaction

Rituximab can also cause type I reactions involving activation of mast cells and basophils. 

Diagnostic criteria for hypersensitivity reactions

Anaphylaxis is highly likely when any ONE of the following three criteria is fulfilled:
   AND AT LEAST ONE OF THE FOLLOWING:
    A. Respiratory compromise
    B. Reduced BP or associated symptoms of end-organ dysfunction (eg, hypotonia, collapse, syncope, incontinence)

References
[1] A Lacasce et al. Infusion-related reactions to therapeutic monoclonal antibodies used for cancer therapy. Uptodate. 

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