HSV-2 therapeutic vaccine program. Subunit vaccine candidates

Transcription

1 HSV-2 therapeutic vaccine program Subunit vaccine candidates

2 Our HSV-2 vaccine program Therapeutic subunit vaccine T-cell-based Aim: Best-in-class antigens by engineering Excellent standing (Sept 2017): Redbiotec preclinical vaccine leads show > 90% reduction of lesion score (vs. approx. 50% for GEN-003 of Genocea) 2

3 HSV-2: Opportunity for a new vaccine Seroprevalence HSV-2, y/o: 16 % (U.S.) New genital herpes cases / year (U.S.): High number of symptomatic patients: 10-25% Standard treatment: antivirals Economic burden (U.S.): > 1 bn USD/year 3

4 Track record of Redbiotec in novel proteins Deals closed with pharma companies in U.S., Asia and Europe Trade sale of spin-off Redvax to Pfizer for its CMV vaccine program Internationally recognized scientists as scientific advisors Engineering and production of >100 novel proteins and protein complexes First company having successfully developed stable CMV pentamer at >95% purity 4

5 HSV-2 therapeutic vaccine program Preclinical data

6 Redbiotec s HSV-2 preclinical program Our goals: To develop a potent T-cell-based therapeutic vaccine against HSV-2, that: - reduces frequency of genital lesion recurrences, and/or - reduces symptoms & time to lesion healing, and/or - decreases duration of shedding and eventually prevents transmission Our tools: Immunogenicity prediction tools Human PBMC database of HSV-2/-1, HSV-2 and HSV-1 samples The guinea pig model of genital infection Set of new immunological assays /reagents Our target sites: Primary infection: epithelial cells Recurrent herpetic disease: genital tract Back to latency Primary herpetic disease: genital tract RBT Reactivation and re-infection Nearby nerve endings Anterograde transport RBT Latency in sensory ganglia Retrograde transport Our products: Recombinantly produced HSV-2 antigens (RBT-x) (22 different purified antigens) 6

7 Overview of Redbiotec s HSV-2 preclinical stages antigen selection process in silico immunogenicity in vitro immunogenicity in vivo immunogenicity & protection in vivo protection & MOA lead candidate(s) Q1-Q Q Q Q3-Q Q data mining searches 35 antigenic sequences selected web-based prediction tools different prediction methods 22 recombinant antigens generated screens with human PBMC samples cytokine profile assays 12 antigens further selected animal studies in guinea pigs (phase 1+2) disease markers immunogenicity markers 4 antigens further selected antigen combinations tested in animals (phase 3) specific antigens to be further selected final selection: 1-2 antigens evaluation of pharma partners 7

8 in vivo STUDIES with the guinea pig model 8

9 In vivo study design: therapeutic protective efficacy of RBT antigens against recurrent infection and disease Days ACUTE INFECTION LATENCY End of Study Guinea pig groups 1-14 HSV-2 infection Immunization with adjuvanted RBT antigens Boost Daily lesion scoring (from D27): frequency and severity Viral shedding determination CD4 + / CD8 + T-cells: frequency and function Acute vaginal infection following intravaginal inoculation of HSV-2 (virus titers shed & severity (clinical score 0-4)) Schematic view of the guinea pig study. Twelve recombinant antigens were tested for protection against recurrent genital herpes in 2 different studies using 5-6 animals per vaccination group in each study. 9

10 Summary of the performance of RBT antigens in the guinea pig model of genital HSV-2 infection Antigen for immunization + No. of animals Frequency of recurrencies * Days with Positive days * Therapeutic Disease recurrencies per animal severity efficacy (D27 to 85) (D27 to 85) (D27 to 85) Severity of disease Mean score per animal (by D85) Therapeutic efficacy RBT % % RBT % % RBT % % RBT % % RBT % % RBT % % RBT % % RBT % % RBT % % RBT % % RBT % % RBT-25a % % RBT-25b % % HSV-2 dl % % Adjuvant alone % % * scores were done every day between Day 27 and 85 (85 days p.i.) + data points of antigens that were tested in both phases (using 10 or 12 animals in total) were pooled to calculate the therapeutic efficacy RBT-23 corresponds to Redbiotec s gd, RBT-25a and b correspond to different formulation of the same antigen Results were obtained with either 12, 10 or 6 animals per vaccination group. Shown are a) the mean of the days with recurrent events in each group and b) the mean of the severity of the events in each group, within Day 27 and Day 85 (p.i.). 10

11 RBT-3 and RBT-26 strongly reduce the number of herpetic recurrent events Days with recurrencies Severity of disease Results represent groups of the phase 2 study with either 6 or 5 animals per vaccination group. Shown are cumulatively a) the mean of the days with recurrent events in each group and b) the mean of the severity of the events in each group, from Day 27 to Day 85 (p.i.). 11

12 H S V -2 s h e d d in g (D N A c o p y n u m b e rs ) H S V -2 s h e d d in g (D N A c o p y N o.) RBT-3 very efficiently protects against virus shedding in the vaginal mucosa Virus shedding average values D a y 3 5 D a y 4 0 D a y 4 5 D a y 5 0 D a y H S V -2 s h e d d in g (D N A c o p y n u m b e rs ) R B T -3 R B T -3 R B T -5 R B T -5 R B T -1 1 R B T -1 1 R B T -1 2 R B T -1 2 R B T -1 4 R B T -1 4 R B T -2 3 R B T -2 3 R B T -2 4 R B T -2 4 R B T -2 5 R B T -2 5 R B T -2 6 R B T -2 6 d l5-2 9 d l5-2 9 A d j. a lo n e A d j. a lo n e 0 R B T -3 R B T -5 R B T -1 1 R B T -1 2 D a y 3 5 D a y 3 5 D a y 4 0 D a y 4 0 D a y 4 5 D a y 4 5 D a y 5 0 D a y 5 0 D a y 5 5 D a y 5 5 R B T -1 4 R B T -2 3 R B T -2 4 R B T -2 5 R B T -2 6 d l5-2 9 Guinea pig vaginal secretions were evaluated by qpcr every 5 days, from Day 35 to Day 55 post infection, for HSV-2 DNA shedding. Samples with <150 copies/ml by 40 cycles were reported as negative. Shown is the average value of 5-6 animals. Data points derive from Phase 2 samples. RBT-23 corresponds to Redbiotec s gd. 12

13 RBT-3 very efficiently protects against virus shedding in the vaginal mucosa Virus shedding distribution of single values D a y 4 5 Day 35 H S V -2 s h e d d in g (D N A c o p y N o.) HSV-2 shedding (DNA copy No.) H S V -2 s h e d d in g (D N A c o p y N o.) HSV-2 shedding (DNA copy No.) H S V -2 s h e d d in g (D N A c o p y N o.) HSV-2 shedding (DNA copy No.) HSV-2 shedding (DNA copy No.) D a y 3 5 H S V -2 s h e d d in g (D N A c o p y N o.) R B T -3 R B T -5 R B T -1 1 R B T -1 2 R B T -1 4 R B T -2 3 R B T -2 4 D a y 5 0 R B T -2 5 R B T -2 6 H S V -2 d l5-2 9 A d j. a lo n e R B T -3 R B T -5 R B T -1 1 R B T -1 2 Day 45 Day 50 Day 55 R B T -1 4 D a y 5 5 R B T -2 3 R B T -2 4 R B T -2 5 R B T -2 6 d l5-2 9 A d j. a lo n e R B T -3 R B T -5 R B T -1 1 R B T -1 2 R B T -1 4 R B T -2 3 R B T -2 4 R B T -2 5 R B T -2 6 H S V -2 D l5-2 9 A d j. a lo n e 0 R B T -3 R B T -5 R B T -1 1 R B T -1 2 R B T -1 4 R B T -2 3 R B T -2 4 R B T -2 5 R B T -2 6 d l5-2 9 A d j. a lo n e Guinea pig vaginal secretions were evaluated by qpcr every 5 days, from Day 35 to Day 55 post infection, for HSV-2 DNA shedding. Samples with <150 copies/ml by 40 cycles were reported as negative. Shown is examples of Days 45 and 55. Data points derive from Phase 2 samples. RBT-23 corresponds to Redbiotec s gd. 13

14 IF N - s e c r e tin g c e lls fr o m s p le n o c y te s (S F U ) RBT antigens show immunogenicity upon re-stimulation of HSV-2-infected cells RBT-3 neg. ctrl 0 R B T -3 R B T -5 R B T -6 R B T -1 1 R B T -1 2 R B T -1 4 R B T -1 5 R B T -2 1 R B T -2 3 R B T -2 4 R B T -2 5 R B T -2 6 P H A n e g. c tr l RBT-23 PHA pos. ctrl The IFN-γ secretion by splenocytes from HSV-2-infected guinea pigs after re-stimulation with 12 recombinant antigens was measured by ELISPOT. Representative images are shown. RBT-23 corresponds to Redbiotec s gd. 14

15 Increased CD4 + /CD8 + responses are detected in RBT-immunized guinea pigs CD4 + frequency CD8 + frequency CD8 + /NKT activation marker Exhaustion marker 25 Pos Cont Neg Cont T-cells positive for various markers were detected in spleen samples from immunized animals using flow cytometry. Both % and absolute numbers were obtained. The bar graphs show absolute cell numbers. Statistical analysis was done with two-tailed unpaired t-test. Asterisks represent P<0.05 compared to the negative control (Adjuvant alone). Positive control is the dl5-29 virus control. RBT-23 corresponds to Redbiotec s gd. An example of the flow cytometry charts with % of CD4+/CD8+ populations is shown. 15

16 Functional T- and B-cells are identified in RBT-immunized guinea pigs Summary of immunological responses Activation markers Exhaustion markers CD8+ frequency CD4+ frequency CD69 on CD8+ CD69 on CD4+ CRTAM MHC II B220 on B-cells IgM PD-1 2B4 RBT-3 RBT-23 RBT-25 dl5-29 Adj. alone highest response lowest response Lymphocytes positive for various markers were detected in spleen samples from immunized animals with selected antigens (three and the two study controls) using flow cytometry. Both % and absolute numbers were obtained. A representation of the strength of the response is shown in form of a heat map based on absolute cell numbers. RBT-23 corresponds to Redbiotec s gd. 16

17 in vitro IMMUNOGENICITY assays with human samples 17

18 S F U / 2 x P B M C RBT antigens show immunogenicity in stimulated HSV-2 patient-derived PBMC HSV-1/-2-double infected donors HSV-2-only infected donors R B T -3 R B T -5 R B T -6 R B T -7 R B T -1 1 R B T -1 2 R B T -1 3 R B T -1 4 R B T -1 5 R B T -2 0 R B T -2 1 R B T -2 2 R B T -2 3 R B T -2 4 R B T -2 5 R B T -2 6 The IFN-γ response of donor PBMC was determined by ELISPOT (13 HSV-2-infected individuals (HSV-2-only and HSV-1/-2-double infected) and 16 antigens analyzed). Each dot represents one positive donor. In blue the HSV-2-only-infected individuals are depicted. Assay signal background is subtracted. Mean values are shown. 18

19 S F U / 2 x P B M C PBMC from HSV-1-positive donors respond with low levels of IFN-γ upon HSV-2 antigen stimulation HSV-1-only-infected donors control donors R B T -3 R B T -5 R B T -6 R B T -7 R B T -1 1 R B T -1 2 R B T -1 3 R B T -1 4 R B T -1 5 R B T -2 0 R B T -2 1 R B T -2 2 R B T -2 3 R B T -2 4 R B T -2 5 R B T -2 6 The IFN-γ response of donor PBMCs was determined by ELISPOT (11 HSV-1-infected individuals or 8 HSV-negative individuals, and 16 antigens analyzed). Each black dot represents one control donor. Assay signal background is subtracted. Mean values are shown. 19

20 RBT antigens elicit IFN-γ responses in both CD4 + and CD8 + T-cells CD4 T-cell + co-culture with or IFN-γ mature Mo-DC antigen CD8 T-cell Donor 4 Donor 23 Donor 55 Donor 75 Donor 101 Donor 125 Donor 51 RBT-3 RBT-5 RBT-14 RBT-23 RBT-25 RBT-26 CD4 responses CD8 responses n.d. strong response medium to low response no response * Donors: HSV-2-only or HSV-1/-2 double-infected Mature Mo-DCs from HSV-2-positive samples were pulsed with RBT antigens and co-cultured with donor-derived CD4 + or CD8 + T-cells. The IFN-γ response was measured by ELISPOT. 20

21 HSV-2 therapeutic vaccine program at Redbiotec: achievements as of Q Twenty two different HSV-2 recombinant antigens (RBT-x) were successfully expressed and purified In vivo guinea pig studies revealed high therapeutic protective efficacy of single antigens: - 88% and 93% efficacy of RBT-3 in reducing frequency and severity of recurrencies, respectively - virus shedding in vaginal secretions upon RBT-3 immunization below the detection limit - single antigens stimulating T-cell immune responses In vitro assays with human PBMC also revealed the immunogenicity of the RBT HSV-2 antigens Potential to increase antigen performance by: - optimization of epitope content - evaluation of adjuvant systems - combination of antigens Three patents on Means and Methods for Treating HSV were filed in March

22 Current collaboration partners UC Irvine, School of Medicine Swiss Federal Institute of Technology Blood Donation Center, Zurich Instituto de Biologia Experimental e Tecnológica Zurich University of Applied Sciences 22

23 Thank you Redbiotec AG Wagistrasse Schlieren, Switzerland (phone) (fax) Dr. Lilli Stergiou