Radioimmunotherapy

1. Radioimmunotherapy Allison Spencer July 27, 2006

2. Radioimmunotherapy • Uses the body’s immune system to deliver toxic radiation to cancerous cells • Special combination of factors: • Tumor antigen targeting • Monoclonal antibodies • Radionuclides • Localized treatment

3. Bio 101: Antigens • Molecules that stimulate an immune response • Proteins or polysaccharides on cell surfaces • Many different types • Tumor Antigens • Tumor Associated • Tumor Specific

4. Bio 101: Antibodies • Large, Y shaped proteins • Identify and neutralize antigens • Induce apoptosis • Cell cycle redistribution • Multiple antibodies for every antigen

5. Monoclonal Antibodies • Highly specific • Clones of single cell • Fuse B cell and tumor cell • Screen for antibody production

6. Radioimmunotherapy • Adds a radioactive molecule to a monoclonal antibody (MoAb) Yttrium 90 labeled MoAb

7. Non-Hodgkin’s Lymphoma • 58,870 cases will be diagnosed in 2006 • 5th leading cause of cancer death • Traditionally treated with: • Chemotherapy • External beam therapy • Immunotherapy

8. RIT and Non-Hodgkin’s 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

9. Process of Attack Cancerous B Cell 90Y

10. 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

11. 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

12. Radioimmunotherapy Allison Spencer