The document summarizes recent developments in cancer immunotherapy, focusing on immune checkpoint blockade and the potential role of mesenchymal stem cells. It notes that between 2011-2016, the FDA approved several immune checkpoint inhibitors (targeting PD-1, PD-L1, CTLA-4) for various cancer types including melanoma, lung cancer, kidney cancer, and Hodgkin's lymphoma. While these drugs have shown success, many patients still do not respond. The document discusses using engineered mesenchymal stem cells to deliver immunotherapeutic agents directly to tumors, with the goal of overcoming adaptive immune resistance in the tumor microenvironment and improving response rates to immunotherapy.

2.  US FDA approved immune checkpoint blockers:
 2011  ipilimumab (anti-CTLA-4)  melanoma
 2014  pembrolizumab (anti-PD-1) melanoma
 2014  nivolumab (anti-PD-1)  melanoma
 2015  pembrolizumab (anti-PD-1)  lung cancer
 2015  nivolumab (anti-PD-1)  lung cancer
 2015  nivolumab + ipilimumab combo  melanoma
 2016  nivolumab (anti-PD-1)  kidney cancer
 2016  nivolumab (anti-PD-1)  Hodgkin’s lymphoma
 2016  atezolizumab (anti-PD-L1)  bladder cancer
 PD-1 or PD-L1 clinical trials:
 ≥ 700 registered trials for PD-1 or PD-L1 blockers.
 ≥ 10 PD-1 or PD-L1 trials for mesothelioma.
Recent Breakthroughs in
Cancer Immunotherapy

3. Programmed death-1 (PD-1) and programmed
death ligand-1 immune checkpoints.
PD-1/PD-L1 Immune Checkpoint
Blockers for Cancer
PD-1 or PD-L1
blockers
TCR
MHC
PD-L1
CD80
PD-L1
PD-L1
PD-1
PD-1
CD80
PD-L1
T Cell
Antigen Presenting Cell
(lymphoid organs)
Tumor “Microenvironment”
(periphery)

4.  Nivolumab / pembrolizumab / atezolizumab.
 Extended overall survival.
 Tumor shrinkage in select cases (15-25%).
• For most cancers complete remission is rare.
• Nivolumab + ipilimumab = 10-20% complete remission in melanoma
(Larkin, et al., 2015 & Postow et al., 2015).
 Responding patients experience durable benefit that can last years
after stopping treatment.
 Pembrolizumab (PD-1) in pleural mesothelioma (AACR 2015):
 Partial response in 28% patients (25 patients treated; Alley, et. al).
 Avelumab (PD-L1) in pleural/peritoneal mesothelioma (ASCO
2016):
 Partial response in 9.4% patients (53 patients treated; Hassan, et. al).
Clinical Effects of
PD-1/PD-L1 Blockers

5. Galectin-9
TCR
MHC
PD-L1
PD-1/PD-L1
blockers
PD-L1
CD80
T cell
Tumor
Adaptive Immune Resistance in
the Tumor Microenvironment
PD-1 TIM-3
upregulate
Modified from Wong et al., 2016

6. Combination Immunotherapy
to Combat Immune Resistance
PD-1 blocker
“common denominator”
CTLA-4 blocker
Other Biological
Response Modifiers
TIM-3 blocker PD-L1 blocker

7. Biological Response Modifiers
for Enhancing T Cells
Modulate the activity of T cells in tumor tissue:
 Promote T cell trafficking (influx to tumors)
• Chemokines
 Promote T cell survival and effector function
• Cytokines
Tumor-targeted delivery methods:
 Novel fusion proteins
 Nanoparticles
 Mesenchymal stem cells
• Natural tumor homing properties
• Possibly “universally compatible”

8.  Multi-potent  can develop into different cell types
 Fat
 Cartilage
 Bone
 Muscle (e.g., heart)?
 Neurons?
 Blood vessels?
 Can be harvested from:
 Bone marrow
 Body fat
 Umbilical cord blood
 Term placenta
Mesenchymal Stem Cell
Properties
Tissue maintenance / regeneration
Mesenchymal stem cells in culture

9. Pre-Clinical Efficacy of
MSCs in Mesothelioma Model
Sage et al., 2014
Intrapleural
treatment
Systemic
treatment

10. Isolating Mesenchymal Stem
Cells From Primary Tissue
Digest / Separate
Adherent Cell Mixture
+ MSC Growth Medium
~4 weeks
(clear unwanted
cells)
Expanded / Pure MSCs
Cryopreserve
Placenta / Bone Marrow
(or other sources)

11. Engineered MSCs to
Produce Human Cytokines
 Producing MSC prototype therapeutics:
 Adenoviral-mediated genetic engineering of mesenchymal stem cells.
• Interleukin-12
• Interferon-α
Adenovirus-IFN-α
or
Adenovirus-IL-12
MSCs
IFN-α or IL-12
secretion
In Vitro Screen
Enhance human T cells?

12. IL-12-Producing MSCs
Boost Human T Cells
Ad-IL-12 Ad-IFN-α
Ad-Mock
(control)
Unmodified
(control)
CD8
CFSE proliferation
77.4% 22.8% 34.1% 39.2%
CD4
19.4% 10.5% 12.1%4.71%
Ad-IL-12 Ad-IFN-α
Ad-Mock
(control)
Unmodified
(control)

13. 0.1
1
10
100
1000
10000 Mock Virus
Ad-IFN-a2
IL-12
Alterations in MSC
Secretome BiologyFGF-2
Eotaxin
TGF-a
G-CSF
Flt-3L
GM-CSF
Fractalkine
IFN-a2
IFN-g
GRO
IL-10
MCP-3
IL-12(p40)
MDC
IL-12(p70)
IL-13
IL-15
sCD40L
IL-17A
IL-1RA
IL-1a
IL-9
IL-1b
IL-2
IL-3
IL-4
IL-5
IL-6
IL-7
IL-8
IP-10
MCP-1
MIP-1a
MIP-1b
TNF-a
TNF-b
VEGF
EGF
Ad-IL-12
IFN-α
FoldChangevs.Control

14. Pleural Effusion After
P/D Surgery in Meso Patients
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
Meso Pt #1
FGF-2
TGF-a
G-CSF
Flt-3L
GM-CSF
Fractalkine
IFN-a2
IFN-g
GRO
IL-10
MCP-3
IL-12(p40)
MDC
IL-12(p70)
IL-13
IL-15
sCD40L
IL-17A
IL-1RA
IL-1a
IL-9
IL-1b
IL-2
IL-3
IL-4
IL-5
IL-6
IL-7
IL-8
IP-10
MCP-1
MIP-1a
MIP-1b
TNF-a
TNF-b
VEGF
EGF
Eotaxin
Meso Pt #2
Meso Pt #3
Control #1
Control #2
pg/ml
No detectable IL-12

15. Other Biological
Response Modifiers
Immune checkpoint
blockers
T cell activity
- LIGHT
- CCL chemokine family
- CXCL chemokine family
- IL-12
- IL-2
- IL-15
- Soluble CD80
- High affinity PD-1 variant
T cell trafficking
Suicide gene
Clinical safety testing
+

16. Key Points
 Immunotherapy rapidly moving forward as new option for
treating diverse cancers.
 PD-1 / PD-L1 immune checkpoint blockers.
 Combination immunotherapies moving forward.
 Many cancer patients do not respond to immune
checkpoint blockers (≥ 50%).
 Complete regression / disease remission still rare.
 Countering adaptive immune resistance via combination
immunotherapy is likely key to improve tumor responses.
 Mesenchymal stem cells as vectors for countering immune
resistance in tumor microenvironment.
 Deliver immunotherapeutic agents specifically to tumor tissue.

17. Acknowledgements
Pacific Mesothelioma Center
Irina Ianculescu, PhD
Steven Ching
Tonya Lee
Blair Kimble
UCLA / West Los Angeles VA
Robert Cameron, MD
Research Funding
Pacific Heart, Lung & Blood Institute
Richard M. Shulze Family Foundation
H.N. & Frances C. Berger Foundation
Kazan McClain Partners’ Foundation

18. Personalized vs. Off-The-Shelf
Stem Cell Manufacturing
Personalized
Therapy
10 weeks
Off-The-Shelf
Therapy
Healthy DonorPatient
Immediately
Available
Compatibility?