COLYTIC VIRUSES BIOTHERAPEUTICS AGAINST CA
Tumour Cell Growth
Cell Divides
Cell Death Genes Mutated
Cigarette smoke, UV, pollutants, bad luck
And Divides
And Divides
And Divides…….
Immortalized cells form tumour
u
Genetic Material
Virus
Cell
VIRUS MULTIPLIES
Our bodies are made of billions and billions of cells
Viruses are parasites and can only reproduce inside of cells
Cellular Antiviral Programs… neighbourhood blockwatch!
• Interferon (IFN) is secreted by infected cells• Alerts neighbouring cells to presence of virus• Leads to death of infected cells, prevents growth
of surrounding cells and raises their defenses against infection
IFN
IFN
IFN
Normal Cell Tumour Cell
Mutations in individual genes
Some of the same genes that control cell growth/death are also involved in cellular
anti-viral programs
Antiviral defense: The “Achilles Heel” of Cancer
~70% of Cancer cells have defects in anti-viral programs !!!
Cancer
Virus
Oncolytic Viruses : A targeted approach to Cancer therapy
Because cancers have defects in antiviral responses, this makes it possible to create viruses that replicate in and specifically kill cancer cells!
In addition to antiviral defects, the typical tumor cell…
• Grows rapidly and generates tumors with leaky vasculature
• Expresses high levels of enzymes involved in nucleic acid metabolism (eg. Thymidine kinase or TK)
• Has Hyperactive growth receptor pathways (eg. EFGR, Ras)
Vaccinia Virus
1.Large double-stranded DNA poxvirus ~ 200 kbp
2.Replicates exclusively in the cytoplasm of cells
3.Can’t recombine with cellular DNA in the nucleus
4.Large amount of genes which can be removed or replaced to accomodate transgenes
5.One of the best studied viruses known to man
Vaccinia Virus engineered from live vaccine
Given to > 100 million healthy children world-wide
1800 1980
The JX-594 Oncolytic Vaccinia strain
vaccine straingenome
thymidine kinase
engineered product:JX-594
lac-Zmarker
GMGM-CSFpayload
lac-Z
B18R mutation
1. Viral gene expressing the cellular equivalent of Thymidine kinase has been removed => dependence on high TK levels provided by tumor cells
2. Mutation in B18R gene required to overcome IFN-mediated antiviral response => no consequence in tumor cells have defects in this pathway
3. Added GM-CSF transgene to stimulate an anti-tumor immune response
NORMAL
CANCER
JX
IFN EGFR
JX
JX
TK
E2F
E 2F
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JXJX
JX
JX JX
JXJX
JX
JX
JX
GMGM
GM
GM
JX
JX
JX
JX
JX
JXJX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
GM
GM
GM
GM
GM
GM
GM
JX
JXJXJX
JX
IFN EGFR
X
GM
GM
JX
JX
ras
Vaccinia Virus (JX-594) cancer targeting & three-pronged MOA
T KX
Phase 2: RECIST responses in HCC tumors located
at periphery of cirrhotic liver
Baseline Week 8
Baseline Day 12
Baseline Week 8
JX-594 activity
Stanford Bio-Imaging Center: (S Thorne - Jennerex virus labeled green)
Amplification, spread, cell killing within human tumors
Days, Post JX594 injection
0 2 4 6 8 10 12 14 16 18 20 22 24
Gen
omes
/ 5L
Who
le B
lood
105
106
107
108
Hours, post administration Hours, post administration
4.5 x 107 genome
01201C1
Days, Post JX594 injection
0 2 4 6 8 10 12 14 16 18 20 22 24
Ge
no
mes/
5L
Wh
ole
Blo
od
105
106
107
108
109
1010
1011
8.8 x 109 genome
Pharmacokinetic Profile: Waves of 1˚+ 2˚ Vaccinia Spread in Human Cancer Patients
Days post tumour injection with vaccinia virus
Oncolytic Virus Initial Sites of Infection in Mouse Tumour
CD31-red Virus-GFP-green
TumorVasculature
Steve Thorne University of Pittsburgh
Tumour Vasculature Infection in Patients Treated IV in Ottawa
VV positive tumor
VV infected vessel
VV positive tumor
VV negative stroma
Immunity and OV therapy
IV VSV
Colon Cancer tumour Challenge with
Colon Cancer cells
“Cured” mouse wait 7 months Mice reject
Tumours!
Pre-treatmentPre-treatment After vaccinia After vaccinia
75 year-old man:• Multiple met sites (n=24)
• Complete tumor regressions:
• Injected
• Distant dermal
• Disease-free 3+ years
32 year-old woman:
• Refractory, widespread met
• Complete tumor regressions:
•Injected
•Distant dermal, chest (surg)
• Disease-free 1.5+ years
Long-term Survivors Disease-Free after Vaccinia
Phase I Clinical Trial Metastatic Melanoma
1. Infection & cell lysis
2. Immune response stimulation
3. Vascular disruption
JX-594: novel 3-pronged mechanism-of-actionReplication & GM-CSF expression dependent
primary MOA:
leads to complementary:
Survival (years)
pati
ents
3-4 months life expectancy
renal
melanoma
lung
liver
melanoma
melanoma
colon
+
+
+
+
>/= 8 monthssurvival
melanoma
thyroid
thymic
melanoma
colon
colon
melanoma
melanoma
15long-term
Survivors(1)
7
cancer types
(1) Based on data from ~43 8-mo evaluable patients to date.
Ph 1 long-term survival: many cancer types
Promising Ph 2 survival in advanced liver cancerSuperior to internal & historical controls, including sorafenib
Lancet Oncology 2009 (n=226)
Hep0072010 (n=22)
IV response summary
% p
atie
nts
(n=6) (n=4) (n=4) Full dose(n=9)*
*Note: Response rate assessment incomplete
IV delivery: biopsy-proven cancer-specific targeting
Colon cancerglandular structures = infected (IHC+)
& evolving necrotic tumor tissue
But What do we do when tumors resist infection with OVs?
Clinical data so far with JX-594 and other oncolytic viruses suggest that significant therapeutic responses can be obtained in a subset of patients
1. Negative single strand RNA virus of the Rhabdovirus family
2. Small genome, 5 gene products (N, P, M, G, L)
3. Potent cytolytic
VSV M protein
-plays a role in virion budding
-causes cell rounding and induces cell death
-interacts with nuclear export machinery prevent expression of cellular antiviral genes
VSV51 : Mutation in M protein at methionine 51 prevents interaction with nuclear machinery
=> Sensitivity to antiviral signaling eg. Interferon
V
VV V
V
V
V
V
= Antiviral defense pathway
VVV
V
V
V
V
VVV
V
V
V
V
VVV
V
V
V
V
Normal Cell
HighlySensitive
Moderately Sensitive
Tumor Cells
Resistant
V
VV V
V
V
V
V
= Antiviral defense pathway
VVV
V
V
V
V
VVV
V
V
V
V
VVV
V
V
V
V
Normal Cell
HighlySensitive
Moderately Sensitive
Tumor Cells
Resistant
Can we complement the defects of VSV51 in resistant tumors using a chemical complementation strategy?
Drugs?
Resistant
Screen design
4T1 mouse breast cancer cells
Controls (SAHA/DMSO)
Library Compounds
4h pre-treat
Add control (media) Add VSV51at low MOI (0.03)
40h incubation
Add Alamar Blue (fluorescent viability dye)
2h incubation
Measure fluorescence
Calculate normalized viability ratio (VSV-treated/Control) for each drug => Low ratio indicates viral sensitizer
High Throughput screen identifies novel “virus sensitizer” or VSe drugs
In vitro validation of VSe compounds
Identification of VSe candidates
VSe1 increases viral replication in cancer but not normal cells
Up to > 1000-fold increase in virus Up to > 1000-fold increase in virus in cancer cells !in cancer cells !
VSe1 represses VSV51-induced genes
Overall # of genes affected by VSe1 = 111Overall # of genes affected by VSe1 = 111
immune cells
virus infection & cell lysis
tumor-targeting antibodies
shutting off tumor blood supply
AcknowledgementsBell/Atkins labDr. John BellDr. Harry AtkinsDr. Fabrice LeBoeufDr. Markus Vaha-KoskelaHeather MacTavishTheresa FallsJulie CoxAlanah KempNicayla KeathJad Farah
Jennerex BiotherapeuticsDavid KirnCaroline BreitbachTae Ho HwangTheresa HickmanAdina PelusoKelley ParatoAnn MoonManijeh Daneshmand
HTS Facility (McMaster)Jenny WangJan BlanchardRyan BrownDr.Eric Brown
Lichty LabDr. Brian LichtyFrances Lai
Auer LabDr.Rebecca AuerLisa Mackenzie
InstitutionsOHRIUniversity of OttawaMcMaster University
Funding AgenciesFRSQOICR