)

Controlled Human Malaria Infection:

Strength of a human challenge model

Robert Sauerwein

2

Plasmodium life cycle in human host

Clinical symptoms

& Pathology

Controlled Human Malaria Infection (CHMI)

Infective

mosquito bite

Microscopy positive

treatment

Liver stage Blood stage

End of

study

R. Sauerwein et al. Nat Rev Immunol 2011

Parasitaemia after CHMI

RTQ-PCR N=48

Microscopy N=48

• Parasitemia in 100% of the volunteers

• Microscopy: Thick smear positive day 7-12

• RTQ-PCR: Cyclic growth of parasites

Treatment

Treatment

Parasitaemia after CHMI

RTQ-PCR N=48

Microscopy N=48

• Parasitemia in 100% of the volunteers

• Microscopy: Thick smear positive day 7-12 (sensitivity

4000 par/ml)

• RTQ-PCR: Cyclic growth of parasites (sensitivity 20 par/ml)

Treatment

Treatment

Hermsen C et al. MBP: 2001

Parasitaemia by qPCR after bites of 5 infected mosquitoes

in 7 CHMI trials in a total of 64 volunteers.

post- infection

Sauerwein R et al, unpublished

+ microscopy

for parasites

Controlled Human Malaria infection (CHMI)

bites of 5 Pf NF54 infected mosquitoes

2 4 6 8 10 12 14 16 18 20 22 24

qPCR (20 Pf/ml)

blood-stage

Thick smear (4000Pf/ml))

Liver-stage

Treatment at thick-smear positive

Data from 48 volunteers in 7 CHMI trials

Roestenberg et al., JID, 2012

Sauerwein R et al, Nat Rev Immunol 2011

1

10

100

1000

10000

100000

4 5 6 7 8 9 10 11

1 +

# P

f /

ml

Days after infection

Statistical model Fitting the data into THE MODEL

Hermsen C et al AMJTMH 2004

# Hepatocytes infected: 207 (29-560)

Asexual cycle 43.7 hrs (42.2-45.6)

rings 28.3 hrs

mature trophs 15.4 hrs

Multiplication factor : 7.50 (6.1-9.6)

Pre-patent period :

MPS 8.8 days (7.3-10.3)

PCR 6.8 days (6.7-7.3)

Estimated parasitological parameter values

Hermsen C et al AMJTMH 2004:71:196

(a) Pre-erythrocytic vaccine

1

10

100

1000

10000

100000

1000000

4 6 8 10 12

Days after infection

1 +

# P

f /

ml

(b) A-sexual stage vaccine

1

10

100

1000

10000

100000

1000000

4 6 8 10 12

Days after infection

1 +

# P

f /

ml

0 %

60%

95%

99%

0 %

30%

60%

90%

Simulated kinetics of parasitemia for different vaccine efficacies

Hermsen C et al AMJTMH 2004:71:196

Bloodstage vaccine

Liver-stage vaccine

Harmonization of Design and Conduct of CHMI

by Mosquito bite

CHMI Mosquito Centers in the world:

1. USMMVP, US

2. Sanaria/ NIH/ University of Maryland, US

3. Seattle Biomedical Research Institute , US

4. Oxford University, UK

5. Radboud University Medical Centre,NL

Input from USAID, US FDA, NIAID, PATH MVI, EC and EVI. Input from WHO committees

Meetings: Bethesda, MD, USA in March 2009; Arusha, Tanzania March 2010 ; Washington, DC in June

2010 (WHO); Amsterdam, June 2011 (EMVDA)

PfSPZChallenge: aseptic cryopreserved sporozoites

(Sanaria)

PfSPZ challenge

• Advantage: • Easy access for global application in appropriate clinical settings. • RadboudUMC, NL, Oxford University, UK, Tuebingen University, Germ. CRESIB, Spain, NIH, US. U. Maryland, US, IHC,

Tanzania, KEMRI, Kenya ,MRTC, Mali, etc

•

: However:

30-100 fold less potent compared to Pf-infected mosquitoes bites: • Viability/potency • Administration (route, device, volume)

13

In vivo imaging of Pb GFP-Luccon parasites

Intravenous versus intradermal injection of sporozoites

i.v injection

i.d injection

44 hrs post

infection

Ploemen I. et al: Vaccine 2103

Administration of aseptic cryopreserved sporozoites

(Sanaria)

Direct intravenous inoculation

Bypass the skin

3200 Spz (30-60 mosquitoes)

•5-10x more potent than ID or IM

•Bypass of immune interference

against spz in the skin

Administration of Pf-infected red blood cells intravenously

Centres:

•QIMR, Austr.

•Oxford University, UK

•RadboudUMC, NL

Cheng AMJTMH 1997; Pombo Lancet 2002

Sanderson AMJTMH 2008, Bijker PNAS 2013

Parasite growth after blood stage infection

PCR determined parasite growth curves

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9

Days after inoculation

Pa

ras

ite

s/m

l Subject 1

Subject 2

Subject 3

Subject 4

Subject 5

Sanderson et al. AJTMH 2008; 878

Blood stage challenge

• Advantage: • Measurement of 4-5 asexual multiplication cycles (compared to 2-3

cycles after mosquito challenge) • However:

• Inoculum (1800 iRBC) is unphysiologically low:

10-20x lower than iRBC from 1 infective spz • Is missing sporo/pre-erythrocytic and cross stages antigens

• blood stage and sporo/liver stages: LSA3, AMA1, MSP1……

• Potential induction of immune responses by very low

parasitemia trivial?

18

CHMI model:

Infection

but

what about protection?

The hunt for Correlate of Protection

20

Protection: • RTS/S: P. falciparum CSP fused to HBsAg/AS01E 30-50% NEJM 2011 365:1863; NEJM 2012 367 2283; NEJM 2013 368:1111 Thera et al NEJM 2011;365:1004 www.who.int/vaccine_research/links/Rainbow/en/index.html

RTS/S Sub-unit vaccine

Interim Results Efficacy Phase IIb/III trial

Efficacy CHMI parallels Phase IIb/III outcome

Limited success of these subunit vaccines

• Poor immunogenicity of individual antigens, Adjuvants; Viral platforms; Prime boost strategies

• Antigenic diversity of the selected target proteins Genetic diversity coverage • Insufficient breadth and coverage of the induced

immune response based on mostly single antigens. Antigen Mix/ Match or Attenuated whole parasite

Chemo-Prophylaxis and Sporozoites (CPS) Immunization

Chloroquine

Roestenberg & McCall et al., NEJM, 2009

Roestenberg et al., Lancet, 2011

Chloroquine Prophylaxis and Sporozoites (CPS) Immunization

Parasitemia post Challenge

qPCR

Chloroquine prophylaxis (3 months)

CPS Immunization

3 x 12-15 PfSpz infected mosquito-bites 5 PfSpz infected mosquito-bites

Protection after CPS-immunization

CPS-immunization induces 100% homologous protection.

Roestenberg & McCall et al., NEJM, 2009

CPS-induced protection is immunization dose-dependent

Roestenberg & McCall et al., NEJM, 2009

Bijker & Bastiaens et al., PNAS, 2013

Bijker & Teirlinck et al., JID 2014

5/10

3/5

8/9

19/20

1. Which immune responses are induced by CPS-immunization?

2. Can any of these immune responses correlate with sterile

protection from re-infection?

Dissect CPS-induced immune signature

CPS Immune Reactive

84 Antigens

Reactive in Both

90 Antigens

Semi-Immune Reactive

238 Antigens

CSP

LSA1

MSP2

MSP10

MSP1

MSP (H101)

MSP11

LSA3

Antigen targets of CPS-induced antibodies Comparing CPS Antibody profile with semi-immune Kenyan sera

Felgner Ph et al Sci Rep 2013

Pre-erythrocytic

antigens

Cross-stage

antigens

Blood stage

antigens

Immune Correlate of Protection

Chemo-Prophylaxis and Sporozoites (CPS)

Analysis of cellular immune responses

Antibodies

CD4 T cells: IFNγ +/- IL-2

CD8 T cells: IFNγ Cytotoxicity CD107a: degranulation marker Granulysin / Granzyme B: cytotoxic molecules

Cytotoxic immune responses in vitro

after CPS immunization (C-1).

Bijker E et al. JID 2014

The RUMC Clinical Malaria Program after >300 CHMI

Controlled human Malaria Infections (CHMI):

• Major upgrade by introduction of molecular detection of parasites by qPCR and development of statistical model

Chemo-Prophylaxis and Sporozoite (CPS) immunization :

• Simple and novel immunization regime inducing long lasting sterile protection with 95% efficacy

• “Better than Nature “ immunzation protocol challenges dogma’s on

naturally acquired malaria immunitity

• Biomarker for protection: First steps in delineation of protective immune signatures

• Identification of (new) target antigens for protection by system immunological approach

Many modalities of

Controlled Human Malaria Infections

and thus

a Fit-for-Purpose Model

Pagina 31

bbb

Clinical team

Else Bijker

Guido Bastiaens

Matthew McCall

Meta Roestenberg

Jorien Wiersma

Linda Wammes

Remko Schats

Quirijn de Mast

Andre van der Ven

Leo Visser

Perry van Genderen

Immunology team Anne Teirlinck

Wiebke Nahrendorf Marije Behet Anja Scholzen

Parasite team

Marga vd Vegte-Bolmer Rianne Siebelink-Stoter

Wouter Graumans

Mosquito team Geert-Jan van Gemert

Laura Pelser-Posthumus Astrid Pouwelsen

Jacqueline Kuhnen Jolanda Klaassen

GAP team

Ben van Schaijk Martijn Vos

Ivo Ploemen Takechi Annoura Shahid Khan Chris Janse

Diagnostic team

Rob Hermsen

Theo Arens

Karina Teelen

Lisette van Lieshout

Jaco Verweij

Jaap van Hellemond

CCMS-the Netherlands:

RUMC /LUMC/EMC

Malaria Vaccine Team

Collaborators

•Sanaria

SL Hoffman

STPH Basel/ Bagamoyo

S. Shekalaghi

C Daubenberger

INSERM

Dominique Mazier

J-F. Franetich

•UC Irvine:

Ph. Felgner

•CEVAC – Ghent

L Foquet

G Leroux-Rouls