Transcript Feb 8 2011 PD Day Oncolytic Viruses

ONCOLYTIC VIRUSES
BIOTHERAPEUTICS AGAIN
73,000 CANADIANS WILL DIE THIS YEAR
GENES CONTROL ALL ASPECTS OF GROWTH
Hours
Weeks
Decades
Normal Cell Growth and Death
Cell Death (controlled by “cell death” genes)
Cell Divides
Tumour Cell Growth
Cigarette smoke, UV,
pollutants, bad luck
Immortalized cells form
tumour
Cell Death Genes Mutated
Cell Divides
And Divides
And Divides
And Divides…….
CHEMOTHERAPY
CANCER TARGETED
THERAPIES
Our bodies are made of billions and billions
of cells
Cell
Genetic
Material
Virus
u
VIRUS
MULTIPLIES
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
Immunology 101
Note : The immune system can also be trained to recognize tumors!
Antiviral defense: The “Achilles Heel” of Cancer
Normal Cell
Mutations
in
individual
genes
Tumour Cell
Some of the same genes that control cell
growth/death are also involved in cellular
anti-viral programs
~70% of Cancer cells have defects in
anti-viral programs !!!
Virus
Cancer
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
thymidine
kinase
vaccine strain
genome
GM
GM-CSF
payload
lac-Z
lac-Z
marker
engineered product:
JX-594
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
Vaccinia Virus (JX-594) cancer targeting &
three-pronged MOA
EGFR
IFN
JX
JX
X
T K
NORMAL
X
E 2F
EGFR
IFN
GM
JX
JX
JX
JX
ras
JX
JX
JX
JX
JX
JX
TK
E2F
GM
JX
JX
JX
JX
JX
JX
JX
JX
GM
JX
JX
JX
GM
GM
JX
JX
JX
JX
GM
GM
GM
JX
JX
JX
JX
JX
GM
JX
JX
JX
JX
GM
JX
JX
JX
GM
GM
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
JX
CANCER
JX
JX
GM
JX
JX
ONCOLYTIC
VIRUSES
GROW IN AND KILL TUMOURS
Phase 1: RECIST tumor response in
HCC patient
Baseline
4 cycles
Phase 2: RECIST responses in HCC tumors
located
at periphery of cirrhotic liver
Baseline
Week 8
Week 8
Baseline
Baseline
Day 12
ONCOLYTIC VIRUSES
SELF AMPLIFYING DOSING
JX-594 activity
Amplification, spread, cell killing within human tumors
Stanford Bio-Imaging Center:
(S Thorne - Jennerex virus labeled green)
Pharmacokinetic Profile: Waves of 1˚+ 2˚ Vaccinia Spread in
Human Cancer Patients
Hours, post administration
Hours, post administration
108
4.5 x
107
genome
107
106
105
0
2
4
6
8
10 12 14 16 18 20 22 24
Days, Post JX594 injection
Genomes/ 5L Whole Blood
Genomes/ 5L Whole Blood
01201C1
1011
1010
8.8 x 109 genome
109
108
107
106
105
0
2
4
6
8
10 12 14 16 18 20 22 24
Days, Post JX594 injection
Days post tumour injection with
vaccinia virus
ONCOLYTIC VIRUSES
MINIATURE “BIOLOGICAL
BATTLESHIPS” ATTACK TUMOURS IN
MULTIPLE WAYS
VIRUS ENTERS THROUGH LEAKY
VASCULATURE (24 Hr PI)
Oncolytic Virus Initial Sites of Infection
in Mouse Tumour
Tumor
Vasculature
CD31-red
Steve Thorne University of Pittsburgh
Virus-GFP-green
Tumour Vasculature Infection in Patients Treated IV in Ottawa
VV positive tumor
VV
infected
vessel
VV
positive
tumor
VV
negative
stroma
Necrotic response in distant non-injected
tumor
Baseline
Pt 1304
Day 5
Week 8
Immunity and OV therapy
Colon
Cancer
tumour
Challenge with
Colon Cancer
cells
IV VSV
“Cured” mouse
wait 7 months
Mice reject
Tumours!
Long-term Survivors Disease-Free after Vaccinia
Phase I Clinical Trial Metastatic Melanoma
Pre-treatment
32 year-old woman:
• Refractory, widespread met
• Complete tumor regressions:
• Injected
• Distant dermal, chest (surg)
• Disease-free 1.5+ years
75 year-old man:
• Multiple met sites (n=24)
• Complete tumor regressions:
• Injected
• Distant dermal
• Disease-free 3+ years
After
vaccinia
JX-594: novel 3-pronged mechanism-of-action
Replication & GM-CSF expression dependent
primary MOA:
1. Infection & cell lysis
leads to complementary:
2. Immune response
stimulation
3. Vascular disruption
JX 594 Clinical Activity
Ph 1 long-term survival: many cancer types
+
+
renal
melanoma
lung
melanoma
+
melanoma
melanoma
patients
+
thyroid
liver
thymic
melanoma
colon
colon
melanoma
melanoma
colon
Survival (years)
3-4 months
life expectancy
>/= 8 months
survival
(1) Based on data from ~43 8-mo evaluable patients to date.
15
long-term
Survivors(1)
7
cancer types
Intra-hepatic injection of JX-594 for Phase II clinical trial
Promising Ph 2 survival in advanced liver cancer
Superior to internal & historical controls, including sorafenib
Lancet Oncology
2009 (n=226)
Hep007
2010 (n=22)
% patients
IV response summary
(n=6)
(n=4)
(n=4)
Full dose
(n=9)*
*Note: Response rate
assessment incomplete
IV delivery: biopsy-proven cancer-specific
targeting
Colon cancer
glandular structures
= infected (IHC+)
& evolving necrotic
tumor tissue
Clinical data so far with JX-594 and
other oncolytic viruses suggest that
significant therapeutic responses can
be obtained in a subset of patients
But What do we do
when tumors resist
infection with OVs?
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
VSVD51 : Mutation in M protein at methionine 51
prevents interaction with nuclear machinery
=> Sensitivity to antiviral signaling eg. Interferon
Tumor Cells
V
V
V
V
Highly
Sensitive
Normal Cell
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
= Antiviral defense pathway
V
V
Moderately
Sensitive
V
Resistant
Can we complement the defects of
VSVD51 in resistant tumors using a
chemical complementation
strategy?
Tumor Cells
V
V
V
V
Highly
Sensitive
Normal Cell
V
V
V
V
Drugs?
V
V
V
V
V
V
V
V
V
Resistant
V
V
V
V
V
= Antiviral defense pathway
V
V
Moderately
Sensitive
V
Resistant
High Throughput screen identifies novel “virus sensitizer” or VSe drugs
In vitro validation of VSe compounds
Screen design
4T1 mouse
breast
cancer cells
Library Compounds
4h pre-treat
Controls (SAHA/DMSO)
Add control (media)
Add VSVD51at 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
Identification of VSe candidates
VSe1 increases viral replication in cancer
but not normal cells
Up to > 1000-fold increase in virus
in cancer cells !
VSe1 represses VSVD51-induced genes
Overall # of genes affected by VSe1 = 111
VSe1 enhances VSVd51 efficacy in a
resistant CT26 syngenic colon tumor model
VSe1 + VSVD51
VSVD51
PBS
VSe1 enhances VSVd51 replication in human clinical samples
immune cells
shutting off
tumor blood supply
tumor-targeting
antibodies
virus infection & cell lysis
Acknowledgements
Bell/Atkins lab
Dr. John Bell
Dr. Harry Atkins
Dr. Fabrice LeBoeuf
Dr. Markus Vaha-Koskela
Heather MacTavish
Theresa Falls
Julie Cox
Alanah Kemp
Nicayla Keath
Jad Farah
Institutions
OHRI
University of Ottawa
McMaster University
Funding Agencies
FRSQ
OICR
Lichty Lab
Dr. Brian Lichty
Frances Lai
Auer Lab
Dr.Rebecca Auer
Lisa Mackenzie
Jennerex Biotherapeutics
David Kirn
Caroline Breitbach
Tae Ho Hwang
Theresa Hickman
Adina Peluso
Kelley Parato
Ann Moon
Manijeh Daneshmand
HTS Facility (McMaster)
Jenny Wang
Jan Blanchard
Ryan Brown
Dr.Eric Brown