Vector-based Genetic Vaccines: The Ebola story

Stefano Colloca

AMCLI - U. di Cagliari, 4 Dicembre 2014

2

The Vector-based genetic vaccine approach

The Ebola Vaccine story

Contents

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

• Most humans have neutralising antibodies against Ad5

The Problem

Vaccine is NOT effective

7

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

The Solution

9

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

The Ebola story

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

39

Grazie