Cell-Based Therapeutics 3

What FDA Approved Cell Products are Non-Gene Based?

- Stem cell therapies (CD34 HSCs)

- TIL

- Cancer vaccines

What FDA Approved Cell Products are Gene Based?

- TCR T cells

- CAR-T

- CRISPR-edited CD34 HSC

What FDA Approved Cell Products are Immunotherapies?

- TIL

- TCR T cells

- CAR-T

- Cancer vaccines (prostate cancer)

What is Haploidentical Adoptive cell therapy?

- Half-matched

- Family member (mom, dad, or child)

- Parents are always a half-match for their children

- Siblings (brothers or sisters) have a 50% chance of being a half-match for each other

What is HLA-Matched Adoptive cell therapy?

- Fully-matched

- Siblings (25% of cases)

What are the Alternative Adoptive Cell therapies?

- Fully-matched unrelated donor

- Cord blood

T/F - Matching is based on HLA

True

What is HLA?

A protein expressed throughout the body

Current FDA-approved CAR-T and other cell therapies are ------- (same donor and recipient)

autologous

What is Lymphodepletion?

A medical process involving the elimination/destruction of lymphocytes and T cells, typically through chemotherapy, to prepare the body for immunotherapy → before cell therapy infusion

Describe the Lymphodepletion prior to immune cell transfer

- Chemotherapy to prime patient for cell transfer

- The process of removal of immunosuppressive subsets of immune cells, such as Tregs, from recipient (patient)

- Typically done with a combination of cyclophosphamide, fludarabine, busulfan

What are the Lymphodepleting regimens?

- Choice of Lymphodepleting agents depends on therapy and toxicity

- Tumor-infiltrating lymphocytes: Cyclophosphamide + Fludarabine (sometimes with IL-2 or total-body irradiation)

- CAR-T: Cyclophosphamide + Fludarabine

- Adoptive stem cell cell transfer (from blood to blood): Clofarabine + Busulfan; Fludarabine + Busulfan

Describe Fludarabine as a Lymphodepletion agent

- inhibits DNA polymerase, thus synthesis

- Immune cells accumulate F ara-ATP, the active metabolite of fludarabine, making them particularly sensitive to lymphodepletion

- Dosed at ≥25-40mg/m2

Describe Effector cells (E.g., T)

- infused into patients, with or without genetic modification, primarily as outpatient treatments

- Native cell therapies: unmodified immune cells (TILs, HSC transplant)

- Cell-based gene therapies: gene-modified cells (CAR-T/NK, TCR T cell therapies)

Expanded with cytokines (which are proteins, given as single or mixtures, e.g., IL-2, IL-7, IL-15) to _______________________

activate and expand T cells

T/F - Donor matching and pre-treatment of patients (lymphodepletion) are needed in all cases

True

T/F - Donor selection criteria must meet cell activation requirements and safety (e.g., HLA-matched, HLA-haploidentical)

True

T/F - Most-FDA approved cell therapies are for hematopoietic progenitor (Stem cell) transplantation (blood disorders) - HCT/HSCT or HPCT

True

T/F - CAR-T are the second largest FDA-approved group

True

All CAR-T are for blood disorders/cancers, what do CAR-T target the most?

CD19 (e.g., Kymriah)

T/F - TIL therapy is for melanoma (Amtagvi - Lifileucel)

True

T/F - TCR therapy is for synovial sarcoma (Tecelra)

True

T/F - Provenge (dendritic cell vaccine) is for prostate cancer

True

All FDA-approved CAR-T cell therapies are __________

Autologous

All FDA-approved CAR-T and cell-based therapies are ________

ex vivo

Describe Extracellular domain of a CAR

- An antibody-binding fragment

- binds antigens on cancer cells

- enables T cell to more specifically target a tumor-associated antigen once transduced

T/F - CARs are not made from patient's DNA

True

CD28, 4-1BB, and OC40 are?

CAR co-stimulatory domains

Describe All FDA-approved CAR-T cells

- Sourced from peripheral blood

- cord blood is another source; one difference is it has more immune cells than peripheral blood

Genes are most commonly engineered into immune cells virally using what?

Lentiviruses or retroviruses (for all FDA cell therapies)

Lymphodepletion is a chemotherapy given to patients prior to cell, what is the purpose?

To disable immune system to avoid rejection

GvHD and CRS are common side effects of cell therapy, what is the purpose?

- To disable immune system (removal of lymphocytes) to avoid rejection

- Removes, among others, reactive T cells (including Tregs)

What is the most common cryopreserving agent?

DMSO

Does Autologous or Allogenic Cell Therapy NOT require patient selection?

Autologous

What is the Process of Viral Vector (delivered for T cell Engineering)?

1. Apheresis

2. Cell Activation

3. Cell Engineering/Modification (Lentiviral/retroviral vector [frozen and delivered from 3rd party])

4. Expansion

5. Infusion

Describe the Manufacturing of Cell Therapy Drug Substance (viral vector for CAR-T)

- CAR-T therapy uses lentiviral or retroviral vectors as gene delivery tools → used to genetically engineer T cells

- Viral vectors are manufactured separately using a producer cell line (usually HEK293)

- Vectors are formulated and frozen, and shipped to the site of cell therapy product manufacturing

- This is only for engineered cell therapies

- Drug product is the drug substance for non-engineered cell therapies

- Third-party CMOs typically manufacture gene vector (drug substance)

What are the Challenges of Manufacturing Cell Therapies?

- Sterilization of final product not possible → aseptic processing key

- Patient are very sick → need product quickly

- Cell viability requirements cannot always be met (14 of 92 leukemia patients received a dose of Kymriah below FDA-required 80% viability)

- Donor cells cannot always expand optimally, cells are exhausted

- Complex logistics → freeze/thaw necessary multiple times

Describe Provenge

- First cell immunotherapy (dendritic cell cancer vaccine) approved in 2010

- 2014 → company went bankrupt, too expensive to manufacture

Who is not included in Trials when choosing the Study Population for Trial?

Healthy normal volunteers are generally not included in trials for cell-based therapy products

Why are Healthy Normal Volunteers not included in trials for cell-based therapy products?

- Products might have long-term risks or permanent adverse effects

- Expensive

- Invasive and complex to manufacture (autologous therapies esp.)

- Clinical trial candidate selection: likelihood and magnitude of medical benefit, sickest first, and lottery

Describe the Patient Response Rates for CAR-T trials in solid tumors

- Pooled response rate: <20%

- Cell-based therapy, though extremely effective in certain cancers, still struggles in complex cancers

- Reason: immune cells get quickly exhausted

T/F - Cell-based therapies are frozen (cryopreserved) prior to administration

True

Describe Cell Cryopreservation

- the process of freezing of the cell therapy drug product

- Required as cell therapy products cannot be lyophilized easily and enables shipment and storage of the drug product prior to administration

- Drug products are frozen from a few hours to a few days

- Has several issues

Describe the Modes of cryopreservation (LN2)

- Slow cooling → usually -1 degree C/min

- Vitrification → -15,000 degree C/min

- DMSO is most-commonly used cryoprotectant (typically 5-7.5%)