Antibody-Based Therapy to Combat Staphylococcus Aureus Infections

Antibody-based therapy to combat Staphylococcus aureus infections

New perspectives on therapeutic antibodies and vaccines ECCMID - Vienna April 24th, 2017

B. François – CHU Limoges (France) ESCMID eLibrary ECCMID_Vienna_April 2017 © by author Transparency declaration

• Over the past 2 years, steering committee and/or advisory board member for Inotrem, Lascco pharma, GSK, The MedCo, Arsanis, Ferring, Daiichi-Sankyo, Asahi-Kasai • Coordinating principal investigator of an ongoing international phase 2 trial within COMBACTE, an IMI-funded program testing a mAb against S. aureus to prevent VAP in ICU patients in collaboration with MedImmune • Coordinating principal investigator of a recently terminated international phase 1b trial testing a mAb against S. aureus to treat VAP in ICU patients in collaboration with Aridis ESCMID eLibrary ECCMID_Vienna_April 2017 © by author Antibiotic resistance Bigger Toll Than Cancer ?

ESCMID eLibrary ECCMID_Vienna_April 2017 © by author Multidrug resistant bacteria

• Gram-negative - Pseudomonas aeruginosa - Klebsiella pneumoniae - Acinetobacter baumanni - Enterobacteriaceae - Stenotrophomonas maltophilia

• Gram-positive - MRSA - Methicillin-resistant coagulase negative staphylococci - ResistantESCMID Enterococci eLibrary ECCMID_Vienna_April 2017 © by author Targeting resistance or virulence ?

1. Bacterial species 2. Mechanisms 3. Ecological niche 4. Host

ESCMID eLibrary ECCMID_Vienna_April 2017 © byBeceiro, author CMR 2013 ; Rudkin, JID 2012 Anti-infective alternatives to antibiotics

• Bacteriophages • Lysins • Immune stimulation • Toxin sequestration (liposomes) • Antimicrobial peptides • Anti-biofilm peptides • Vaccination • Probiotics  Monoclonal antibodies (mAb) ESCMID eLibrary ECCMID_Vienna_April 2017 © by authorCzaplewski, Lancet ID 2016 A German story !

"for his work on serum therapy, especially its application against diphtheria”

"in recognition of their work on immunity“

Mechinov discovered phagocytosis ESCMIDErlich discovered eLibrary antibodies ECCMID_Vienna_April 2017 © by author Why antibodies for bacterial infections?

• Specificity - No impact on the beneficial microbiome - No environmental exposure • Safety - Not targeting host mechanisms - No drug-drug interactions with small molecules

• Long half-life - Potential single dose protection for 1-3 months • Antibiotic preservation - mAb MOAs will not select antibiotic cross resistance - Antibody prophylaxis could decrease antibiotic use - Adjunctive use could reduce resistance • MAb ESCMIDMOAs can complement antibiotics eLibrary - Mabs can enable host to better fight infection and limit damage ECCMID_Vienna_April18 2017 © by author New mAb lead generation strategy

• Hybridoma technology - Murine and humanized • Human-derived mAb phage libraries - “Normal human” - Patient-derived • In licensing and collaboration • Human B-cell technology - Healthy immunized and convalescent

• Multiple animal models to emphasize different aspects of pathogen infection and disease • Fc engineering to further enhance activities and half lives • Multi -ESCMIDspecific, multi-functional emphasis foreLibrary mAb candidates ECCMID_Vienna_April 2017 © by author mAb-based AVAs provide multiple immunological MOA

ESCMID eLibrary ECCMID_Vienna_April 2017 © bySellmann author, Caister Academic Press 2011 Prior experiences…..which failed ! Only S. aureus surface components targeted ! • Pagibaximab (humanized monoclonal antibody targeting lipoteichoic acid)  Positive trend but failed to reduce staphylococcal sepsis in neonates • AltaStaph (hyperimmune polyclonal antibodies from individuals vaccinated with StaphVAX)  Failed to reduce incidence of S. aureus bacteremia in neonates or to improve the outcome of patients with persistent bacteremia • Tefibazumab (humanized monoclonal antibodies targeting clumping factor A)  Failed to prevent S. aureus bacteremia relapse, complications or death • Veronate (pooled human hyperimmune preparation targeting clumping factor A)  Failed to reduce the incidence of late-onset sepsis in premature neonates • Aurograb (single-chain fragment of Ig region specific for S. aureus transporter GrfA)  Failed to show efficacy as add-on therapy in deep-seated staphylococcal infections • StaphVAX (bivalent vaccine composed of capsular polysaccharide 5 and CP8)  Failed to reduce the incidence of bacteremia in patients undergoing hemodialysis • V710 (monovalent vaccine composed of the iron-responsive surface determinant B)  FailedESCMIDto reduce incidence of post-operative eLibraryS. aureus bacteremia and major wound infection, associated with an increased incidence of multi-organ dysfunction and mortality ECCMID_Vienna_April 2017 © bySalgado author-Pabon, Nat Rev Microbiol 2014 Nevertheless……increasing focus on antibodies for antibacterial therapy • Staphylococcus aureus * Kenta/Aridis : alpha toxin * Alopexx/Sanofi : PNAG * Xbiotech : protein A * Arsanis : 6 toxins * MedImmune/AstraZeneca : alpha toxin • Pseudomonas aeruginosa * Kalobios/Sanofi : PcrV mAbs * Symphogen/Meiji : 5-10 mixed mAbs * Daiichi-Sankyo : LPS O11 * MedImmune/AstraZeneca : PcrV/Psl bispecific mAbs * Aridis : Alginate mAb • Clostridium difficile * MassBio/Medarex/Merck : Toxin A&B mAbs ESCMIDOther preclinical programs eLibrary ongoing : Klebsiella pneumoniae, E. coli, Acinetobacter baumanii… ECCMID_Vienna_April 2017 © by author Unmet need

Most common pathogens in ICU pneumonia

Total US HAP/VAP/HCAP population: ~645,000 • 10 to 15 % of ventilated patients • 1st cause of nosocomial infection in the ICU • Overcost of 10,000 to 20,000 euros per episode ESCMID• Risk factor for increasedeLibrarymortality in the ICU (attributable around 10 to 15%) ECCMID_Vienna_April 2017 EPIC II.© Vincent JL,by JAMA 2009 author ; NHSN CDC Report 2009-2010 Alternative therapeutic approach

Microbiological Clinical VAP Relapse diagnosis diagnosis Resolution Pre-Colonization Colonization Pneumonia (VAP)

Prevention Pre-emption Treatment Secondary Prevention

Surveillance ESCMID eLibrary ECCMID_Vienna_April 2017 © by authorFrançois, Intensive Care Med 2016 Virulence

Virulence Factor Mechanism of Action

Autolysins Enzymes involved in cell-cell cleavage and eDNA release in biofilm production

Adhesins Polysaccharide intercellular adhesion and fibronectin-binding proteins

Cell lysis by alpha-hemolysin (Hla) and leukocidins, HlgAB, HlgCB, LukED, and LukSF Leukocidins Panton-Valentine leukocidin, LukGH (LukAB), and phenol-soluble modulins

Proteases (eg, GluV8) Digest IgG antibody components and diminish effector function

Superantigens Endotoxin B and exofoliative enterotoxin

Quorum-sensing factors Regulate transcription of RNAII and RNAIII (arg locus) and alpha-hemolysin production Ig binding ESCMID factors Immobilize IgGs and Inhibit engagementeLibrary of host immune factors ECCMID_Vienna_April 2017 ©François, by Semin Respir author Crit Care Med 2017 (submitted) Rationale for alpha-toxin target

• Rationale for anti-exotoxin approach - Neutralization of soluble exo-toxin(s) by antibodies reduces virulence, tissue damage, inflammation, dissemination, and attributable mortality of S. aureus infections - Antibodies targeting exo-toxin virulence factors are not affected by defense mechanisms nor resistance profile of S. aureus - All previous S. aureus mAbs directed against cell-associated targets failed clinically

• Rationale for anti-alphatoxin target - Widely expressed (>90%) in S. aureus strains, genetically stable, no mutation was identified for the past ~40yrs - α-Toxin expression increases with antibiotics exposure - α -Toxin gene knockout or mutant forms of α-toxin lose their virulence ESCMIDin animals eLibrary Anti-toxin antibodies during severe infections associated with improved outcome ! ECCMID_Vienna_April 2017 © by authorFritz, CID 2013 Anti-S. aureus mAb under clinical development

Anti-S. aureus mAbs AR-301 MEDI4893 514G3 ASN100

Company Aridis Medimmune Xbiotech Arsanis

Target Alphatoxin Alphatoxin Protein A 6 toxins Fully human mAb? Yes Yes Yes Humanized % S. aureus strain coverage >95% >95% Unpublished Unpublished Potency Pico-molar Pico-molar Unknown Pico-molar Time to Phase 2 data in Oct. 2016 2Q ‘19 4Q ‘17 2Q ‘18 patients ESCMID eLibrary ECCMID_Vienna_April 2017 © by author AR-301 Efficacy in pneumonia

In vitro Animal model

Time post-dosing 12 hrs 24 hrs

72 hrs % A549 cells killed cells A549 %

20 mg/kg ESCMIDAR-301 (mg/ml) eLibrary MRSA (USA100) data ECCMID_Vienna_April 2017 © by author AR-301 Adjunctive approach: Phase 2a Trial

. Randomized, double-blind, placebo-controlled, single Design ascending dose Number of Patients . 48 patients with HAP or VAP caused by S. aureus . 1 mg/kg or placebo (8 patients) Groups . 3 mg/kg or placebo (10 patients) (all groups received standard of care antibiotics) . 10 mg/kg or placebo (16 patients) . 20 mg/kg or placebo (14 patients) Primary Endpoint . Safety and pharmacokinetics

ESCMID eLibrary ECCMID_Vienna_April 2017 © by author AR-301 Adjunctive approach: Phase 2a Trial

Cohort 1 1 mg/kg Placebo Cohort 1 Cohort 2 Cohort 3 Cohort 4 AR-301/placebo (6:2) 52 65 49 62 61 Age [years (SD)] (25-80) (50-78) (21-69) (47-74) (39-76) Cohort 2 VABP (%) 31 83 50 78 63 3 mg/kg AR-301/placebo 17,5 18,3 21,5 17,9 19,3 (8:4) Apache II (8-25) (16-24) (15-28) (9-23) (12-24)

Cohort 3 AEs related to treatment 2 (2,4%) 1 (3,3%) 0 (0%) 1 (1,3%) 4 (6,8%) 10 mg/kg AR-301/placebo (10:5) SAE 8 (9,8%) 4 (13,3%) 10 (10,9%) 13 (16,3%) 1 (1,7%)

Cohort 4 SAE related to treatment N.A. 0 0 0 0 20 mg/kg AR-301/placebo Death 1 1 2 2 0 (8:5)ESCMID eLibrary ECCMID_Vienna_April 2017 © by authorFrançois, ECCMID 2017 MEDI4893 Murine pneumonia model

Improved Survival

100

12 mpk Bacterial Load (CFU) 80 3 mpk

al c o n t r o l m A b

v MEDI4893* 10 i Lungs

v 1.5 mpk MEDI4 89 3 * mg/k g r

u 60 s 0.5 mpk

t 8

)

n n

15 mpk Control mAb a P=0.011 g

40 r

erce

O /

P 6

F C

20 ( 0

1 4

o L 0 0 1 2 3 4 5 6 2 Day elapsed USA300 3.1x108 mAb administered 24h prior to IN challenge IN = Intranasal ESCMID eLibrary ECCMID_Vienna_April 2017 © by authorHua, AAC 2014 MEDI4893 Reduces lung damage and inflammation

IgG Isotype Control MEDI4893

8000 IL-1 1500 IL-17 40000 MIP-2

6000 30000

l l

1000 l

m m

0 m

/ /

4000 / 20000

pg pg pg 500 2000 10000 # # # # # # 0 0 0

ESCMIDN e g C o n t. Ig G 1 5 m g /k g M E D I4 8 9 3 1eLibrary5 m g /k g U n tre a te d Iso g e n ic A T -K O #p-value< 0.0001 ECCMID_Vienna_April 2017 © by authorHua, AAC 2014 MEDI4893 Adjunctive Therapy in pneumonia 100

l 80

i v

r 60 Cont. IgG 15 mpk u p=0.026*

s VAN 40 mpk/day t n 40

ce MEDI4893* 15 mpk

r e

P 20 VAN-40/anti-AT 15

0 0 1 2 3 4 6 7 VAN q12 for 3 days 5 Day Post-infection 100

l 80

i v r 60

u p=0.027* Cont. IgG 15 mpk s

t LZD 5 mpk/day

n 40 ce

r MEDI4893* 15 mpk e

P 20 LZD-5 + anti-AT 15

0 LZD q12 for 2 days ESCMID0 1 2 3 4 6 eLibrary7 5 Day Post Infection ECCMID_Vienna_April 2017 © by authorHua, AAC 2014 MEDI4893 Immunocompromised pneumonia model

Neutrophil Count S u r v iv a l P o s tin fe c tio n

400 1 0 0

l a

m 300 8 0

v m

CPM 150/100 i

/ v

s *** r

il 6 0

200 u

t t

oph n

r 4 0 t

e *** u

100 Neutropenia c e

r *** N e 2 0

Severe P 0 neutropenia -4 -2 0 2 4 6 0 Days 0 1 2 3 4 5 6 D a y s E la p s e d • Cyclophosphamide (CPM) administered 4 days M E D I4 8 9 3 * 4 5 m g /k g prior to infection (150 mg/kg) and day -1 of M E D I4 8 9 3 * 1 5 m g /k g infection (100 mg/kg). ESCMID eLibraryM E D I4 8 9 3 * 5 m g /k g • Mice infected day 0 with SF8300 (1 x 108 CFU) c - Ig G 4 5 m g /k g ECCMID_Vienna_April 2017 © by authorHua, AAC 2015 SAATELLITE

• Double-blind placebo-controlled phase II trial • Estimated sample size = 285 • To evaluate in mechanically ventilated ICU patients colonized with Staphylococcus aureus ‒ Safety, tolerability, and pharmacokinetics of MEDI4893 ‒ Effects of MEDI4893 on the incidence of S. aureus pneumonia ‒ Biomarkers associated with S. aureus disease severity and outcome

Hla-neutralization: human lung cells Leukocidin neutralization: human phagocytes

ESCMIDHla-only Hla- onlyeLibraryHla-only ECCMID_Vienna_April 2017 © by authorRouha, MAbs 2015 ASN100 Protection in prophylactic pneumonia model

Rabbit Necrotizing Pneumonia Model (USA300 CA-MRSA)

ASN-1: 100% Survival

Hla-only mAb: 25% Survival

Control mAb: 0% Survival ESCMID eLibrary ECCMID_Vienna_April 2017 © by authorDiep, AAC 2016 514G3 Phase 1/2 in Staphylococcal bacteremia

514G3 (XBiotech, Austin, TX) promote opsonophagocytic activity against all forms of S aureus while neutralizing immune evasion mechanism and binds to S aureus protein A

• 52 patients with confirmed blood infection (514G3 vs placebo + antibiotics). Randomized 3:1 during a dose escalation and phase II randomized 2:1 • No drug-related adverse events observed at any of the dose escalation levels and the 40 mg/kg phase II dose • 28 SAEs in 15 patients: – 4 deaths – RRR = 49% for the overall incidence of SAEs in 514G3 group compared to placebo [(8 of 36 (22%) vs 7 of 16 (44%), respectively, (p=0.11)] – RRR = 56% for the incidence of S. aureus-related SAEs in the 514G3 group [4 of 36 (11%) vs 4 of 16 (25%), respectively, (p=0.23)]. ESCMID– Duration of hospitalization reduced by 33eLibrary% in the 514G3 treatment arm compared to the placebo arm [8.6±7 days vs 12.7±9 days (p=0.092)] ECCMID_Vienna_April 2017 © by author Other indications

• Unmet need in both bacteremia and surgical site infection • Mainly adjunctive approach to be probably considered in the short term • Prevention strategy in high risk population (hemodialysis) • More complex model for clinical trial with mAbs (time for intervention and endpoints) • More virulence factors involved or at least with less « prominent role » of alpha hemolysin in disease progression ESCMIDthan in VAP eLibrary ECCMID_Vienna_April 2017 © by author Combined approach

• Anti-AT alone is likely not sufficient for all S. aureus diseases (e.g indwelling devices, hemodialysis patients) • MAb combo product targeting different S. aureus virulence mechanisms • Prevention or adjunctive treatment of serious S. aureus infections including device related infections and infections in hemodialysis patients • Anti-ClfA mAb has protective activity against most S. aureus strains in sepsis models but does not protect by itself in ESCMIDpneumonia or dermonecrosis eLibrary

15 mpk 15 mpk M E D I MEDI4893* 1 0 0 Strain 4 Anti ClfA + l p = 0 .0 1 8 Anti ClfA

a 9 v

i 8 0 3 v r * * u 6 0

s 2784 CC1 + + +

t NRS382 CC5 - + + n N e g . m A b (2 m p k )

e 4 0

c M E D I4 8 9 3 * (1 m p k ) 30409043 CC5 - + + r

e a n ti-C lfA (1 m p k ) 2 0 4211 CC5 + + + P C o m b in a tio n (1 m p k ) SF8300 CC8 - + + 0 0 2 4 6 8 1 0 1 2 3049057 CC8 - - + NRS261 CC30 - - + D a y s p o s t c h a lle n g e 3049157 CC30 + - + ESCMID eLibrary3049048 CC45 - + + ECCMID_Vienna_April 2017 © by authorTkaczyk, mBio 2016. Paradigm Shift Targeted Anti-Infective Therapy

Empirical antibiotic treatment → evidence-based targeted mAb therapies

Better Outcome: Clinical Real time Targeted therapy Improved Assess- diagnostic with mAbs Survival & ment confirmation Resource Utilization ESCMID eLibrary ECCMID_Vienna_April 2017 © by author Conclusions

• Probably one of the most innovative/promising therapeutic option in S. aureus infection • Lung and SSI best indications • Alpha toxin probably the appropriate target • Both adjunctive and pre-emptive approach to be considered • Antibiotics remain central in the treatment strategies • Interest for antibiotics recently approved (Oritavancin, Tedizolid ESCMID, Dalbavancin….) especially eLibraryfor MRSA ECCMID_Vienna_April 2017 © by author Back-up slides

Nosocomial Infections ICU = 4.5 M in US ICUs (11% of NI) N = 418,000

UTI: 26% SSI: 7% Pneumonia: 26% BSI: 21% Others: 20%

N = 110,000 N = 30,000 N = 107,000 N = 87,000 N = 84,000

CoNS 3% CoNS 14% CoNS 1% CoNS 34% S. aureus 2% S. aureus 30% S. aureus 24% S. aureus 10% Enterococcus 15% Enterococcus 11% Enterococcus 1% Enterococcus 16% E. coli 21% E. coli 10% E. coli 5% E. coli 3% Klebsiella 9% Klebsiella 4% Klebsiella 10% Klebsiella 6% Enterobacter 4% Enterobacter 4% Enterobacter 8% Enterobacter 4% P. aeruginosa 10% P. aeruginosa 6% P. aeruginosa 16 % P. aeruginosa 3% AcinetobacterESCMID1% Acinetobacter 1% Acinetobacter eLibrary8% Acinetobacter 2% ECCMID_Vienna_April 2017 © byHidron ,author Infect Control Hosp Epidemiol 2008 Mechanism of nosocomial pneumonia

Colonizing Pre-invasion ICU admission Pneumonia pathogen stage with virulence and intubation with sepsis found in secretions factor production ESCMIDDay 1 Day 6 eLibraryDay 14 Day 16 ECCMID_Vienna_April 2017 © by author ESCMID eLibrary ECCMID_Vienna_April 2017 © byFraunholz, author Front Cell Infect Microbiol 2012 MEDI4893

• Is a potent S. aureus alpha toxin inhibitor • Reduces disease severity, prevents tissue damage and indirectly reduces bacterial burden in disease models. • Alpha toxin neutralization with MEDI4893 allows the host to respond in a manner appropriate to the infection site • Adjunctive activity with antibiotics • FDA Fast Track Designation • « Interesting » PK profile in phase 1– extended half ESCMIDlife eLibrary ECCMID_Vienna_April 2017 © by author MEDI4893 PK in healthy adults

MEDI4893 exposure increased with dose •Low inter-subject variability observed throughout the study across all dose cohorts •Extended half-life of 80-112 days for all dose groups •High doses of 2250 mg and 5000 mg maintained serum exposure above target level of ESCMID211 µg/mL for at least 30 days, as predicted eLibrary ECCMID_Vienna_April 2017 © by authorYu, Am J Respir Crit Care Med 2015