Radioimmunotherapy

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Radioimmunotherapy

• Allison Spencer
• July 27, 2006

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Radioimmunotherapy

• Uses the bodys immune system to deliver toxic
  radiation to cancerous cells
• Special combination of factors
• Tumor antigen targeting
• Monoclonal antibodies
• Radionuclides
• Localized treatment

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Bio 101 Antigens

• Molecules that stimulate an immune response
• Proteins or polysaccharides on cell surfaces
• Many different types
• Tumor Antigens
• Tumor Associated
• Tumor Specific

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Bio 101 Antibodies

• Large, Y shaped proteins
• Identify and neutralize antigens
• Induce apoptosis
• Cell cycle redistribution
• Multiple antibodies for every antigen

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Monoclonal Antibodies

• Highly specific
• Clones of single cell
• Fuse B cell and tumor cell
• Screen for antibody production

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Radioimmunotherapy

• Adds a radioactive molecule to a monoclonal
  antibody (MoAb)

Yttrium 90 labeled MoAb
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Non-Hodgkins Lymphoma

• 58,870 cases will be diagnosed in 2006
• 5th leading cause of cancer death
• Traditionally treated with
• Chemotherapy
• External beam therapy
• Immunotherapy

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RIT and Non-Hodgkins Lymphoma

• Specific antigen targeted CD20
• Tumor associated
• Does not shed or internalize
• Isotopes used
• Yttrium-90 half life 64 hours, beta emitter
• Iodine-131 half life 8 days, alpha and gamma
• Vary in conjugation

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Process of Attack
Cancerous B Cell
90Y
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Advantages of RIT

• Precision of treatment
• Less damage to healthy tissue
• Irradiation of nearby, unbound cells
• Patient comfort
• 1 hour intravenous procedure
• Y-90 outpatient administration

Unbound cells receive toxic radiation
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RIT Success in NHL

• With traditional treatments
• Low grade kills 95 of patients in first 5 years
• Aggressive kills 50 of patients in first 5
  years
• Yttrium-90 labeled Zevalin
• 80 overall response rate with Y-90 Zevalin
• 34 complete response
• 32 still in remission 3-4 years later

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Radioimmunotherapy

• Allison Spencer