Module 2 Lecture 8 Cancer Immunotherapy PDF

Module 2 Lecture 8 Cancer Immunotherapy  Sci Transl Med. 2013 March 20; 5(177): 177ra38 The pdf of the article is found in the files folder for module 2. Students should read and understand this article  Topics/What to...

Module 2 Lecture 8 Cancer Immunotherapy  Sci Transl Med. 2013 March 20; 5(177): 177ra38 The pdf of the article is found in the files folder for module 2. Students should read and understand this article  Topics/What to Know/Understand Students should concentrate their study of this publication to the aspects discussed during the lecture, including: 1. How was the immune system directed to target the cancer? What immune cells, where did they come from, how were they modified to target the cancer? 2. On what basis was it possible to target an immunotherapy to the cancer cells and not affect normal cells too severely? 3. Did it work? 4. Pitfalls and implications for trying the same strategy on other cancers.  Background Patients with relapsed B-cell ALL (B-ALL) have a very poor prognosis – 4.5 months avg survival, 10% after 5 years. Long term survival depends on achieving complete remission (CR) which only then can receive transplant of allogeneic HSCs – Repopulates the hematopoietic niche Most patients cannot achieve CR, so are not eligible to receive the transplant  Terminology & Strategy Tumor-associated antigens are molecules expressed by tumor cells and not by normal cells in the body – Or at least not too many normal cells.... (risks?) Genetically construct a chimeric antigen receptor (a TCR) that is designed to specifically bind to a tumor-associated antigen Train the T-cells and re-introduce them into the patient so that they target cells expressing the tumor-associated antigen  CD19: Tumor Associated Antigen Cluster of differentiation 19 (CD19) is normally expressed on B-cells both immature naïve and non-naïve – Also on some dendritic cells Is a receptor that binds complement proteins and co-stimulates B-cells that have bound antigens via the BCR – If complement has been activated, this will influence the threshold for activating a naïve B-cell or re- activating a memory B cell Highly expressed on many varieties of lymphomas and leukemias, including B-ALL  Methods I: T-cell Isolation Isolated peripheral blood mononuclear cells (PBMCs) from each patient and sort them based on CD3 and CD28 (T-cells) – CD3 recognizes all T-cells – CD28 does similar, but antibody binding to CD28 activates the T-cells (superagonist for co-stimulatory receptor) Procedure: 1. Mix fluorescently tagged antibodies (anti-CD3 and anti-CD28) with PBMCs 2. Run through FACS sorter, that selectively isolates the CD3+/CD28+ population This process also activates the T-cells  Methods II: Engineering a CAR Use a virus that has been genetically engineered to deliver a gene into T cells that codes for a chimeric antigen receptor (CAR) – What kind of virus would you use? CAR is a Franken protein consisting of an external domain based of the antigen- binding domain of an antibody and a cytoplasmic domain that stimulates T-cell mediated killing of any cell displaying the ligand that binds the CAR – Binds with specificity of antibody – Functions like a TCR, but engineered to be more potent in terms of signaling to the T- cell to kill the cell with the ligand In the case of this paper, the ligand is CD19, a protein on surface of B-ALL cells (and normal cells too!) Juno therapeutics  Methods III: Getting Enough Cells “Transduced” T-cells (infected with the virus to express the CAR) are proliferated in a bioreactor system to generate enough of the T-cells to achieve the required dose  Now Again, Simple this Time Chimeric receptor has external domain that recognizes the tumor associated antigen and internal domain that stimulates the cell to attack the target Leukemia & lymphoma society  Methods IV: Treatment Patients matching the entry criteria (relapsed B-ALL without CR) for the clinical trial were first administered cyclophosphamide – DNA alkylating agent (guanine) that interferes with DNA replication Patients infused with 1.5 to 3 x 106 T-cells (called 19-28z+ T-cells) Treatment Schemes  Response: Bone marrow aspirates Prior to treatment: Lots of the same type of cell (cancer) D11: Depletion of cells within bone marrow D59: Repopulation of normal hematopoietic niche  Response: Circulating Cell Types The makeup of the blood cells labeled for CD19 (x-axis) ad CD10 (another marker of cancerous cells) shows a rapid and prolonged decline in the proportion of cells within the blood that express these two receptors  Response: Adverse Events * Corresponds with initiation of steroids for some patients (blue, red) MSK-All04 & 05 had the highest disease burden of all the patients (63% & 70% blast rate) Persistent fever is very common in patients Febrile neutropenia is fever with low neutrophil count Why/how would this occur as a result of the treatment? Response: Circulating Inflammatory Cytokines * Corresponds with initiation of steroids for some patients (blue, red) MSK-All04 & 05 had the highest disease burden of all the patients (63% & 70% blast rate) Cytokine levels correlate with the tumor burden at the time of CAR treatment  Outcomes 4 of 5 patients became eligible for allo-HSC transplant MSK-ALL01 died of suspected pulmonary embolus 2 months after allo-HSC while in CR MSK-ALL03, 05 & 06 remain in CR at time of publication (18 months, 3 months & 6 weeks) MSK-ALL04 went into CR, but couldn’t get the allo- HSC due to co-morbidities. Relapse occurred 13 weeks after T-cell infusion and the patient expired MSK-ALL04 After Relapse (2nd) After relapse, blood was taken from ALL04 & assessed if the cancer cells were still expressing CD19 – They did What might it mean if they no longer expressed CD19? Patient Characteristics & Outcomes MRD = Minimal residual disease (+ means yes, - means no)  Conclusions? Did the CAR therapy eliminate cancer cells preferentially? Was CAR therapy safe? Did the CAR therapy prolong lifespan? Did the CAR therapy increase quality of life? What was this study missing that would have made it easier to draw these conclusion? If you had a relative with refractory B-ALL, would you suggest they participate in the phase II clinical trial? Could this treatment be used directly on other types of cancer? – What modifications would need to occur to use this to treat other types of cancer?  Update FDA grants approval (Aug 30th, 2017) to CAR T- cell therapy for children and young adults with B-cell acute ALL. Product commercial name is Kymriah – Product of Novartis First gene therapy product approved in US https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm574058.htm http://www.cnn.com/2017/08/30/health/fda-first-gene-therapy-leukemia/index.html End Lecture