CAR-T Cell Therapy

Question 1

What do helper T cells do?

Answer 1

Upon binding a specific antigen, helper T cells secrete cytokines to stimulate the differentiation of B cells into plasma cells (antibody-producing cells)

Question 2

What do cytotoxic T cells do?

Answer 2

Upon activation, cytotoxic T cells bind and kill infected cells and cancer cells

Question 3

What is the TCR-CD3 complex?

Answer 3

TCR is noncovalently associated with a signaling complex consisting of:
* CD3EY heterodimer
* CD3ED heterodimer
* CD3SS homodimer

Question 4

What is ITAM?
What does it do?

Answer 4

Immunoreceptor tyrosine-based activation motif
- Bind ZAP70 to initiate the TCR signaling pathway → activation of T cells

Question 5

Upon exposure to target cells (infected cells and cancer cells), activated cytotoxic T cells release perforin, granzyme and granulysin. What do these do?

Answer 5

1. Perforin: forming pores on target cell membranes
2. Granzyme: inducing apoptosis of target cells
3. Granulysin: forming pores in microbial cell walls

Question 6

Explain the mechanisms of evasion of cancer cells from immunosurveillance (5)

Answer 6

1. Overexpression of CD47 expression → binds SIRPα on macrophages and reduces the attack on cancer cells
2. Downregulation of MHC I molecules → unrecognition of antigens
3. Lack of costimulatory signals → example: downregulation of CD80
4. Secretion of immunosuppressive molecules
5. Modulation of antigens

Question 7

What are 4 strategies in developing immunotherapy against cancer?

Answer 7

1. Bring cytotoxic T cells to cancer cells via an interaction other than TCR-MHC I
   - Overexpression of cancer antigens on cancer cell surface
   - Develop binding options against cancer antigens
   - Express cancer antigen-specific receptor on the surface of
   cytotoxic T cells (outside of cytotoxic T cells)
2. Maintain and enhance the stimulatory signals within cytotoxic T cells
   - Keep CD3S (inside of cytotoxic T cells)
3. Add a hinge and transmembrane domain to link the surface receptor and CD3S
4. Leading to the development of first-generation CAR*

Question 8

What is CAR?

Answer 8

Chimeric antigen receptor (targeting a specific antigen in cancer cells, such as CD19)

Question 9

What is a CAR T cell?

Answer 9

Engineered T cell with CAR on the surface

Question 10

What is CAR T cell therapy? (4)

Answer 10

1. Collect T cells from a patient’s blood
2. Add the chimeric gene (encoding CAR) into the T cells in a laboratory
3. Grow and collect CAR T cells in the laboratory
4. Infuse CAR T cells into the patient

Question 11

What is the core of CAR (first generation) (4)

Answer 11

1. scFv: single-chain variable fragment
   - Bind cancer antigen molecule
2. Hinge
3. Transmembrane domain
4. CD3S
   - Bind ZAP70 and activate TCR signaling pathway

Question 12

What is single-chain variable fragment (scFv)? (2)

Answer 12

1. Fusion protein of the variable regions of heavy chain (VH) and light chain (VL) of antibodies
2. CDR: complementarity- determining regions
   - Binding specific antigens

Question 13

What are the components that have been added to CAR since the second generation? (3 + subpoints)

Answer 13

1. Co-stimulators
   - CD28 (Ig superfamily): binding CD80/CD86
   - 4-1BB (CD137, tumor necrosis factor receptor superfamily): binding 4-1BBL
   – Second generation CAR: one co-stimulator along with CD3
   – Third generation CAR: two co-stimulators along with CD3
2. NFAT transcription factor: stimulating IL-12 production
   - Fourth generation of CAR
3. JAK-STAT activation domain derived from IL2Rβ: stimulating cell proliferation and inhibiting terminal differentiation by expressing JAK and STAT3
   - Fifth generation of CAR

Question 14

What are the challenges of CAR T-cell therapy? (4)

Answer 14

1. Time consuming
2. High cost
3. Hostile tumor microenvironment: interfering with T cell activity in terms of differentiation and exhaustion
4. T cell exhaustion: progressive loss of effector function due to prolonged antigen stimulation

Question 15

What are the FDA approved CAR T-cell therapies (brand names) (6)

Answer 15

1. Kymriah
2. Yescarta
3. Tecartus
4. Breyanzi
5. Abecma
6. Carvykti

Question 16

What is B-lymphocyte antigen CD19? (4)

Answer 16

1. Surface glycoprotein: ~95 kDa
2. Expressed in early stages of B cell development
3. Biomarker for lymphoma and leukemia
4. Universally expressed in B-cell acute lymphoblastic leukemia

Question 17

What is B-cell maturation antigen (BCMA) (5)

Answer 17

1. Cell surface receptor
2. A member of the TNF-receptor superfamily
3. Preferentially expressed in mature B lymphocytes
4. Overexpression and activation are associated with multiple myeloma
5. Biomarker for multiple myeloma

Question 18

What is the MOA of Kymriah (tisagenleceleucel)? (2)

Answer 18

1. 4-1BB as the co-stimulator
2. Targeting CD19 antigen

Question 19

What is the indication of Kymriah? (2)

Answer 19

1. B-cell precursor acute lymphoblastic leukemia
2. Diffuse large B-cell lymphoma

Question 20

What is the MOA of Yescarta? (2)

Answer 20

1. CD28 as the co-stimulator
2. Targeting CD19 antigen

Question 20

What is the indication of Yescarta? (2)

Answer 20

1. Diffuse large B-cell lymphoma
2. Follicular lymphoma

Question 21

What is the MOA of Tecartus? (2)

Answer 21

1. CD28 as the co-stimulator
2. Targeting CD19 antigen

Question 22

What is the indication of Tecartus?

Answer 22

Mantle cell lymphoma

Question 23

What is the MOA of Breyanzi?

Answer 23

1. 4-1BB as the co-stimulator
2. Targeting CD19 antigen

Question 24

What is the indication of Breyanzi?

Answer 24

Diffuse large B-cell lymphoma

Question 25

What is the MOA of Abecma? (2)

Answer 25

1. 4-1BB as the co-stimulator
2. Targeting B-cell maturation antigen (BCMA)

Question 26

What is the indication of Abecma?

Answer 26

Multiple myeloma

Question 27

What is the MOA of Carvykti? (2)

Answer 27

1. 4-1BB as the co-stimulator
2. Targeting B-cell maturation antigen (BCMA)

Question 28

What is the indication of Carvykti?

Answer 28

Relapsed/refractory multiple myeloma