Vector-based Genetic Vaccines: The Ebola story
Stefano Colloca
AMCLI - U. di Cagliari, 4 Dicembre 2014
PATHOGENS
Antibodies
T CD4
T CD8
Antibodies
T CD4
T CD8
Antibodies
T CD4
No CD8
Attenuated Inactivated
MICROORGANISMS
VACCINES
(I° generation)
RECOMBINANT PROTEINS
(II° generation)
Pathogens and Vaccines may induce different immunity
3
CD8 T cell induction requires intracellular synthesis of the antigen
MHC-I
TCR
Endogenous
Antigen synthesis
CD8 T cell response
4
Gene encoding
Pathological Antigen
Antibodies
T CD8
mRNA
MHC I
Antigenic
peptide Antigen
Genetic Vaccines induce both T cells and Antibodies
5
BUT DNA does NOT efficiently transfect human cells in vivo
Why Adeno?
• Viral Vectors are efficient Genetic Vaccine carriers
Pre-clinical and clinical studies with non replicating human Adenovirus 5 have shown it to be safe and highly immunogenic
6
8
Adenovirus vectors from rare human serotypes are weak immunogens in mice and NHP*
* Colloca et al. Science Translational Medicine, 2012
Ad5 Ad6 Ad24 Ad35 Ad3410 - 1 1
10 - 1 0
10 - 9
10 - 8
10 - 7
10 - 6group B
group C
group Dre
cip
roca
l o
f ve
cto
r d
ose
(vp
)
Ad5 Ad6 Ad26 Ad24 Ad35 Ad340
200
400
600
800
1,000
1,0001,500 1010vp
108 vp
IFN S
FC
/10
6 P
BM
C
A B
Human Ad
mice macaques
Okairos’ Ad vectors derived from chimpanzees
• Okairos isolated and screened samples from over 700 chimpanzees
• All primates were healthy and well cared for in US and EU facilities
• High frequency of adenovirus isolation – strains belonging to species B, C and E
Okairos’
chimpanzee Ad vectors
10
High
productivity
High
potency
Low
pre-existing
immunity
Clinical
safety
11
Phylogenetic tree of human and chimpanzee Ad vectors
Human Adeno
Chimp Adeno
Structurally similar
Serologically distinct
12
ChAd vectors are potent immunogens in mice and NHP*
* Colloca et al. Science Translational Medicine, 2012
Ad5 Ad6 Ad24 Ad35 Ad3410 - 1 1
10 - 1 0
10 - 9
10 - 8
10 - 7
10 - 6group B
group C
group Dre
cip
roca
l o
f ve
cto
r d
ose
(vp
)
Ad5 Ad6 Ad26 Ad24 Ad35 Ad340
200
400
600
800
1,000
1,0001,500 1010vp
108 vp
IFN S
FC
/10
6 P
BM
C
A B
Human Ad
macaques mice
Ch
Ad
3
Pan
Ad
3
Ch
Ad
63
Pan
Ad
1
Pan
Ad
2
Ch
Ad
83
Ch
Ad
11
Ch
Ad
19
Ch
Ad
20
Ch
Ad
24
Ch
Ad
31
Ch
Ad
6
Ch
Ad
9
Ch
Ad
10
Ch
Ad
43
Ch
Ad
55
Ch
Ad
14
7
Ch
Ad
4
Ch
Ad
5
Ch
Ad
7
Ch
Ad
16
Ch
Ad
38
Ch
Ad
14
6
Ch
Ad
14
9
Ch
Ad
15
0
Ch
Ad
30
10 - 1 0
10 - 9
10 - 8
10 - 7
10 - 6group B
group C
group E
recip
roca
l o
f ve
cto
r d
ose
(vp
)
A B
ChAd3 PanAd30
500
1,000
1,500
2,000
2,0003,000
1010vp
108 vp
IFN S
FC
/10
6 P
BM
C
Chimp Ad
mice macaques
Weak
Potent
Potent
Chimp Adeno are insensitive to pre-existing anti-Adeno immunity present in in humans (data from HCV vaccine program*)
13 * Barnes et al. Science Translational Medicine, 2012
High Ad5 NAb No Ad5 NAb
10
100
1000
10000 IF
N
SF
C/1
06 P
BM
C
Multiple clinical studies have validated safety and potency of ChAd vectors in humans
HCV
Phase I trial
Malaria
Phase I trials
10
100
1,000
10,000
hAd6
HCV
Okairos’ ChAd3
Okairos’ ChAd63
Okairos’ ChAd63
Okairos’ ChAd63
HCV Malaria
Antigen 1 Malaria
Antigen 2 Malaria
Antigen 3 Antigen:
Vector:
Dose (viral particles): 2.5x1010 2.5x1010 5x1010 5x1010 5x1010
IFN
SF
C/1
06 P
BM
C
• Barnes et al. Science Translational Medicine, 2012; O’Hara J.Infect. Disease, 2012; • Sheehy et al. Molecular Therapy, 2011; collaboration with T. Hanke, U. Oxford
HIV
Phase I trial
Okairos’ ChAd63
HIVcons
5x1010
14
Immunological goal is induction of effective
antibody and CD8 T cell responses for
both short and long term protection
The Okairos vaccine is based on the surface glycoprotein GP
ChAd3*
BGH poly A HCMV promoter
E4 Orf6 from Ad5
Gene inserts Replace E1
Okairos/NIH ChAd3 Ebola Vaccine
17
• E3 deleted in SUDV, but not EBOV.
1976 Mayinga strain of
EBOZ
Adapted from Tran E E H et al. J. Virol. 2014;88:10958-10962
RBS FL
18
The primate model of Ebola infection and Ad-based vaccine
• Infected by the human filoviruses (Ebola, Marburg)
• Similar infection kinetics and disease
• 100% mortality rate
• Most likely animal model for FDA vaccine approval (“animal rule”)
• Immunological assays available
• Mechanism of protection based on CD8 T cells*
MODEL:
VECTOR:
• ChAd3 encoding the Ebola glycoprotein GP
*Sullivan NJ, Nat Med. 2011 Aug 21;17(9):1128-31
Strategy to Identify a Lead Ebola Vaccine Candidate
Weeks
rAd Ebola virus challenge
1 2 3 4 0
1: Identify prime(s) that provides uniform protection against short term challenge
2: Define regimen that induces durable immunity
Weeks
Ebola virus
challenge
52 0 4 8
or MVA
20
Ad-vectored Ebola vaccine mechanism of protection
0
20
40
60
80
100
120
CD4+ T cells CD8+ T cells
No depletion cM-T807
% p
re-d
ep
leti
on
No depletion cM-T807*
Time after infection (d)
None (n=5)
cM-T807 (n=5)
Control (n=2)
Pe
rce
nta
ge s
urv
ival
P = 0.01
0
50
100
10 20 30
rAd5-GP Ebola vaccinated macaques treated with cM-T807 become susceptible to Ebola virus infection
suggesting the protective role of CD8+ T cell response.
Passive transfer of high concentration anti-Ebola IgG doesn’t protect macaques from challenge
Sullivan NJ, Nat Med. 2011 Aug 21;17(9):1128-31
Depletion of CD8+ cells abrogates protective immunity against Ebola virus
*Depleting anti-CD8α antibody (cM-T807)
Protection Against Ebola Challenge
After rAd5-GP Vaccination in Preimmune Subjects
Prior Ad5 immunity reduces the potency of rAd5-based
Ebola vaccines
0
50
100
Vaccine:
Ad5 Immunity:
Ad5-GP
Naive
Ad5-GP
Pre-immune
Su
rviv
al (%
pro
tec
ted
)
21
ChAd3-ZEBOV is immunogenic in non human primates
Experimental design
1010 or 1011 vp ChAd3 (N=4)
Weeks 0 4 5
Plasma IgG ELISA PBMC ICS
1000 pfu ZEBOV
ChAd3 induced anti-GP IgG titers above the correlate cut-off that predicts 100% protection for Ad5
Ad5 average
B cell response
ChAd3 and Ad5 induce comparable levels of anti-GP CD4 and CD8 T cells
T cell response
Ad5 average
Ad5 average
% P
r o t e
c t io
n
100
80
60
40
20
0
Ad5 ChAd3
Acute protection
ChAd3-ZEBOV induces 100% protection from EBOV challenge
Ebo l a v ir us ch all en g e
V a cc i n a t e ChAd Ebo l a G P n = 4 / g r oup
W ee k s : 0 1 2 3 4 5 One year
Ebolavirus challenge
Ebo l a v ir us ch all en g e
collaboration with N.Sullivan, VRC – NIH
Durable protection Acute protection
Durable protection
ChAd3
Ebo l a v ir us ch all en g e
ChAd3 GP n = 4 / g r oup
Months : 0 1 2 3 4 5 One year
Ebo l a v ir us ch all en g e
collaboration with N.Sullivan, VRC – NIH
% P
r o t e
c t io
n
100
80
60
40
20
0
Ad5 ChAd3
Acute protection
ChAd3-ZEBOV priming induces 50% protection from EBOV challenge at one year: need for boosting
The Okairos genetic vaccine is delivered by ChAd3 and MVA vectors
Chimp Adeno MVA
33 105 158 227 313 464 501
502
672
GP2 GP1
Furin cleavage
554
651 1
676 SP RBS Glycan Cap Mucin IFL TM
SP: signal peptide
RBS: receptor binding site
IFL: internal fusion loop
TM: transmembrane anchor
Guinea 2014 changes shown in red
Ebola Zaire GP DNA
Durable protection
ChAd3
Ebo l a v ir us ch all en g e
ChAd3 GP n = 4 / g r oup
Months : 0 1 2 3 4 5 One year
Ebo l a v ir us ch all en g e
MVA GP
collaboration with N.Sullivan, VRC – NIH
% P
r o t e
c t io
n
100
80
60
40
20
0
Ad5 ChAd3
Acute protection
ChAd3-ZEBOV prime/MVA-ZEBOV boost induces 100% protection from EBOV at one year
ChAd3/MVA
Relative Potency of ChAd3 and ChAd3/MVA for Durable Immune Memory
CD8
Ab
CD4
ChAd3 ChAd3/MVA
Peak Memory Peak Memory
ChAd3 ChAd3/MVA
Peak Memory Peak Memory
ChAd3 ChAd3/MVA
Peak Memory Peak Memory
Ebola Vaccine – Current status
• On September 4-5 the WHO recommended and
started to support ‘accelerated’ development of
vaccines
• 3000 doses of the Okairos candidate Ebola vaccine
were produced in the GMP labs in Pomezia in 2013
• In September 2014 two trials (US and UK) have been
launched for testing safety and immunogenicity of
this vaccine
29
2014
2015
• Phase I clinical trials for SAFETY, IMMUNOGENICITY, DOSE FINDING
Ebola Vaccine Clinical Development Program: Overall Strategy
2016
• Phase IIa clinical trials for SAFETY, IMMUNOGENICITY in NON ENDEMIC western African countries
• Phase IIb clinical trials for SAFETY, IMMUNOGENICITY and EFFICACY in HCW of ENDEMIC countries
Clinical trials underway or pending
Trial Site PI Product (dose) Phase N Start Date
VRC 207 NIH CC Ledgerwood Bivalent
2e10 & 2e11 I 20 Sept 2014
VRC 207 Part 2 UMD Lyke Monovalent
1e10 & 1e11 I 20 Oct 2014
VRC 207 Part 2 Emory Mulligan Bivalent
2e11 Ib 40-100 Oct 2014
cAd3-EBOZ Lau Lausanne Genton Monovalent
2.5e10 & 5e10 IIa 100 Oct 2014
RV422 MUWRP - Uganda Kibuuka
Bivalent
2e10 & 2e11
Monovalent
1e10 & 1e11
I 90 Dec 2014
TBD UMD - Mali Sow Bivalent
2e10 & 2e11 Ib 30 Dec 2014
EBL01 Oxford - UK Hill Monovalent
2.5e10 & 5e10 I 60 Sept 2014
RPC687 Mali Sow/Levine Monovalent
2.5e10 & 5e10 I 40 Oct 2014
Ongoing Pending
Step1: Phase IIa in non endemic western African countries
Ivory Coast
Gabon Congo
Uganda
Sudan
New Epidemics
Step 2: Phase IIb in Health Care Workers of endemic countries
Ivory Coast
Gabon Congo
Uganda
Sudan
New Epidemics
Trials of the Ebola vaccine ChAd3-EBO progress at speed
Almost 200 people have received ChAd3-EBO in little more than 2 months in phase I trials in USA, UK, Mali and Switzerland:
◦ 20 people at the NIH, USA
◦ 60 people at the University of Oxford, UK
◦ 80 people at the University of Maryland School of Medicine Center for Vaccine Development in Mali
◦ 34 people out of 120 volunteers at the University of Lausanne, Switzerland
Safety and immunogenicity data available up to 4 weeks post vaccination from the first phase I trials:
EBL 01, University of Oxford, UK
Single IM vaccination with 10^10 or 2.5x10^10 or 5x10^10 pfu (EBO Zaire)
20 subjects/ group (tot 60)
VRC2017, NIH, USA
Single IM vaccination with 2x10^10 or 2x10^11 pfu (1:1 ratio of EBO Zaire & EBO Sudan) 10 subjects/ group (tot 20)
The vaccine is safe and well tolerated across different doses
◦ No serious adverse events
◦ Local and systemic reactogenicity, when present was mild to moderate and similar to what reported in previous studies with Ad-based vaccines
◦ Some dose effect (i.e. fever) observed in the VRC207 study
The vaccine is immunogenic and induces anti GP Antibodies - VRC207
VRC207 – Anti GP IgG kinetics measured against GP Zaire and GP Sudan with increasing doses of ChAd3 EBO (Z + S)
- Single vaccine dose induces a GMT at the highest dose (week 4) associated with protection in NHP
Ledgerwood JE, N Engl JMed. DOI: 10.1056/NEJMoa1410863.
The vaccine is immunogenic and induces EBOV specific CD4 and CD8 T cells – VRC207
VRC207 – T cell response measured by polyfunctional ICS on frozen cells with increasing doses of ChAd3 EBO (Z + S) – GP Z specific response is shown
- Induction of polyfunctional CD4 and CD8 T cells (100% positive responders at the highest dose)
Tota
l cyt
oki
ne
re
spo
nse
, % s
ub
set
CD4 memory cells CD8 memory cells
Ledgerwood JE, N Engl JMed. DOI: 10.1056/NEJMoa1410863.
21
ChAd3-ZEBOV is immunogenic in non human primates
Experimental design
1010 or 1011 vp ChAd3 (N=4)
Weeks 0 4 5
Plasma IgG ELISA PBMC ICS
1000 pfu ZEBOV
ChAd3 induced anti-GP IgG titers above the correlate cut-off that predicts 100% protection for Ad5
Ad5 average
B cell response
ChAd3 and Ad5 induce comparable levels of anti-GP CD4 and CD8 T cells
T cell response
Ad5 average
Ad5 average
38
Contributors
Okairos
Riccardo Cortese
Alfredo Nicosia
Virginia Ammendola
Adele Abbate
Fabiana Grazioli
Stefania Di Marco
Loredana Siani
Daniele Bonivento
NIH
Nancy J Sullivan
Richard A Koup
Daphne A Stanley
Clement Asiedu
Lingshu Wang
Cheng Cheng
Mario Roederer
Gary J Nabel
John Mascola
US Army Medical Research
John C Trefry
Anna N Honko
Joshua C Johnson
VRC 207 Trial
Julie E. Ledgerwood
Richard M. Schwartz
Barney S. Graham
Adam D. DeZure
Daphne A. Stanley
Laura Novik
Mary E. Enama
Nina M. Berkowitz
Zonghui Hu
Gyan Joshi
Aurélie Ploquin
Sandra Sitar
Ingelise J. Gordon
Sarah A. Plummer
LaSonji A. Holman
Cynthia S. Hendel
Galina Yamshchikov,
VRC 207 Study Team